Expression profiling of ETO2-regulated miRNAs in erythroid cells: Possible influence on miRNA abundance.
FEBS Open Bio. 2013;3:428-32
Authors: Fujiwara T, Okitsu Y, Katsuoka Y, Fukuhara N, Onishi Y, Ishizawa K, Harigae H
ETO2 is a component of a protein complex containing master regulators of hematopoiesis, including GATA-1 and SCL/TAL1, and also has RNA binding properties. Although ETO2 has been reported to repress GATA-1 target genes through histone deacetylation of the target gene loci in erythroid cells, little is known about the contribution of ETO2 to microRNA (miRNA) regulation. Here, we conducted miRNA profiling in ETO2-overexpressing and ETO2-silenced K562 cells. The analysis suggests that ETO2 positively regulates the abundance of mature miRNAs, including miR-21, miR-29b and let-7e. Our data suggest a novel mode of ETO2-mediated target gene repression via effects on miRNA expression.
PMID: 24251106 [PubMed]
Porcine synapsin 1: SYN1 gene analysis and functional characterization of the promoter.
FEBS Open Bio. 2013;3:411-20
Authors: Hedegaard C, Kjaer-Sorensen K, Madsen LB, Henriksen C, Momeni J, Bendixen C, Oxvig C, Larsen K
Synapsin 1 (SYN1) is a phosphoprotein involved in nerve signal transmission. The porcine SYN1 promoter orthologue was cloned and characterized to provide a means of expressing a transgene specifically in neurons. The nucleotide sequence of the promoter displayed a high degree of conservation of elements responsible for neuron-specific expression. Expression analysis of SYN1 demonstrated presence of transcript during embryonic development. Analysis of GFP expression in transgenic zebrafish embryos suggests that the pig SYN1 promoter directs expression in neuronal cells. Thus, the SYN1 promoter is a good candidate for use in the generation of pig models of human neurodegenerative disorders.
PMID: 24251104 [PubMed]
Therapeutic potential of umbilical cord blood stem cells on brain damage of a model of stroke.
J Cardiovasc Thorac Res. 2011;3(4):117-22
Authors: Nikravesh MR, Jalali M, Ghafaripoor HA, Sanchooli J, Hamidi D, Mohammadi S, Seghatoleslam M
INTRODUCTION: Human cord blood-derived stem cells are a rich source of stem cells as well as precursors. With regard to the researchers have focused on the therapeutic potential of stem cell in the neurological disease such as stroke, the aim of this study was the investiga-tion of the therapeutic effects of human cord blood-derived stem cells in cerebral ischemia on rat.
METHODS: This study was carried out on young rats. Firstly, to create a laboratory model of ischemic stroke, carotid artery of animals was occluded for 30 minutes. Then, umbilical cord blood cells were isolated and labeled using bromodeoxyuridine and 2×10(5) cells were injected into the experimental group via the tail vein. Rats with hypoxic condi-tions were used as a sham group. A group of animals did not receive any injection or sur-geries were used as a control.
RESULTS: Obtained results were evaluated based on behavioral responses and immunohistochemistry, with emphasis on areas of putamen and caudate nucleus in the control, sham and experimental groups. Our results indicated that behavioral recovery was observed in the experimental group compared to the either the sham or the control group. However, histological studies demonstrated a low percent of tissue injury in the experimental group in comparison with the sham group.
CONCLUSION: Stem cell transplantation is beneficial for the brain tissue reparation after hypoxic ischemic cell death.
PMID: 24250968 [PubMed]
Double edged effect of gum-resin of ferula assa-foetida on lifespan of neurons.
Iran J Basic Med Sci. 2013 Apr;16(4):668-71
Authors: Homayouni Moghadam F, Vakili Zarch B, Shafiei M
Objective(s): Based on knowledge from traditional herbal medicine, Ferula assa-foetida (asafoetida) has several therapeutic applications but there is less knowledge about its effect on neurons. Materials and Methods: In order to evaluate neuronal differentiation, neuronal like cells were stained against neuronal specific markers β-Tubulin III and MAP2. After establishment of neuronal differentiation in cultured cells, aqueous extract of gum-resin of asafoetida were applied on culture medium of neurons with different concentrations then survival rate of neurons were evaluated by cell counting and methyl tetrazolium bromide (MTT) tests. Results: The results showed that asafoetida gum resin particularly with 0.01 and 1 µg/ml concentrations could improve survival rate of neurons, while10 µgr/ml treated group was toxic. Conclusion: Results of this study indicated that gum resin of asafoetida in low doses has neuroprotective effect on neurons and improves survival rate of them, however in higher concentrations it is toxic for neurons.
PMID: 24250950 [PubMed]
Double edged effect of gum-resin of ferula assa-foetida on lifespan of neurons.
Iran J Basic Med Sci. 2013 Apr;16(4):660-3
Authors: Homayouni Moghadam F, Vakili Zarch B, Shafiei M
Objective(s): Based on knowledge from traditional herbal medicine, Ferula assa-foetida (asafoetida) has several therapeutic applications but there is less knowledge about its effect on neurons. Materials and Methods: In order to evaluate neuronal differentiation, neuronal like cells were stained against neuronal specific markers β-Tubulin III and MAP2. After establishment of neuronal differentiation in cultured cells, aqueous extract of gum-resin of asafoetida were applied on culture medium of neurons with different concentrations then survival rate of neurons were evaluated by cell counting and methyl tetrazolium bromide (MTT) tests. Results: The results showed that asafoetida gum resin particularly with 0.01 and 1 µg/ml concentrations could improve survival rate of neurons, while10 µgr/ml treated group was toxic. Conclusion: Results of this study indicated that gum resin of asafoetida in low doses has neuroprotective effect on neurons and improves survival rate of them, however in higher concentrations it is toxic for neurons.
PMID: 24250948 [PubMed]
The molecular study of IFNβ pleiotropic roles in MS treatment.
Iran J Neurol. 2013;12(4):149-156
Authors: Kay M, Hojati Z, Dehghanian F
Multiple sclerosis (MS) is one of the most important autoimmune diseases recognized by demyelination and axonal lesion. It is the most common cause of disability in the young population. Various immunomodulatory and immunosuppressive therapies, including different formulations of interferon beta (IFNβ), glatiramer acetate (GA), mitoxantrone, and natalizumab are available for this disease. However, interferon has been the best prescribed. Although the precise mechanism of IFNβ is unclear, many studies indicate some potential mechanism including blocking T cells activation, controlling pro- and anti-inflammatory cytokine secretion, preventing activated immune cell migration through BBB, and inducing repair activity of damaged nerve cells by differentiating neural stem cells into oligodendrocytes. These molecular mechanisms have significant roles in IFNβ therapy. More researches are required in order for us to comprehend the mechanism of action of IFNβ, and improve and develop drugs for more efficient MS treatment.
PMID: 24250925 [PubMed - as supplied by publisher]
The Transcriptional Co-Regulator HCF-1 Is Required for INS-1 β-cell Glucose-Stimulated Insulin Secretion.
PLoS One. 2013;8(11):e78841
Authors: Iwata TN, Cowley TJ, Sloma M, Ji Y, Kim H, Qi L, Lee SS
The transcriptional co-regulator host cell factor-1 (HCF-1) plays critical roles in promoting cell cycle progression in diverse cell types, and in maintaining self-renewal of embryonic stem cells, but its role in pancreatic β-cell function has not been investigated. Immunhistochemistry of mouse pancreas revealed nuclear expression of HCF-1 in pancreatic islets. Reducing HCF-1 expression in the INS-1 pancreatic β-cell line resulted in reduced cell proliferation, reduced glucose-stimulated insulin secretion, and reduced expression of the critical β-cell transcription factor Pdx1. HCF-1 is a known co-activator of the E2F1 transcription factor, and loss of E2F1 results in pancreatic β-cell dysfunction and reduced expression of Pdx1. Therefore we wondered whether HCF-1 might be required for E2F1 regulation of Pdx1. Chromatin immunoprecipitation experiments revealed that HCF-1 and E2F1 co-localize to the Pdx1 promoter. These results indicate that HCF-1 represents a novel transcriptional regulator required for maintaining pancreatic β-cell function.
PMID: 24250814 [PubMed - in process]
MiR-223 Regulates Human Embryonic Stem Cell Differentiation by Targeting the IGF-1R/Akt Signaling Pathway.
PLoS One. 2013;8(11):e78769
Authors: Yu YH, Zhang L, Wu DS, Zhang Z, Huang FF, Zhang J, Chen XP, Liang DS, Zeng H, Chen FP
Currently, there are difficulties associated with the culturing of pluripotent human embryonic stem cells (hESCs), and knowledge regarding their regulatory mechanisms is limited. MicroRNAs (miRNAs) regulate gene expression and have critical functions in stem cell self-renewal and differentiation. Moreover, fibroblast growth factor (FGF) and the insulin-like growth factor receptor (IGF-1R) are key activators of signaling in hESCs. Based on the identification of complementary binding sites in miR-223 and IGF-1R mRNA, it is proposed that miR-223 acts as a local regulator of IGF-1R. Therefore, levels of miR-223 were detected in differentiated versus undifferentiated hESCs. In addition, proliferation, apoptosis, and differentiation were assayed in these two hESC populations and were compared in the presence of exogenous miR-223 and miR-223 inhibitor. Inhibition of miR-223 was found to maintain the undifferentiated state of hESCs, while addition of miR-223 induced differentiation. Furthermore, these effects were found to be likely dependent on IGF-1R/Akt signaling.
PMID: 24250812 [PubMed - in process]
The RNA Binding Protein RBM38 (RNPC1) Regulates Splicing during Late Erythroid Differentiation.
PLoS One. 2013;8(10):e78031
Authors: Heinicke LA, Nabet B, Shen S, Jiang P, van Zalen S, Cieply B, Russell JE, Xing Y, Carstens RP
Alternative pre-mRNA splicing is a prevalent mechanism in mammals that promotes proteomic diversity, including expression of cell-type specific protein isoforms. We characterized a role for RBM38 (RNPC1) in regulation of alternative splicing during late erythroid differentiation. We used an Affymetrix human exon junction (HJAY) splicing microarray to identify a panel of RBM38-regulated alternatively spliced transcripts. Using microarray databases, we noted high RBM38 expression levels in CD71(+) erythroid cells and thus chose to examine RBM38 expression during erythroid differentiation of human hematopoietic stem cells, detecting enhanced RBM38 expression during late erythroid differentiation. In differentiated erythroid cells, we validated a subset of RBM38-regulated splicing events and determined that RBM38 regulates activation of Protein 4.1R (EPB41) exon 16 during late erythroid differentiation. Using Epb41 minigenes, Rbm38 was found to be a robust activator of exon 16 splicing. To further address the mechanism of RBM38-regulated alternative splicing, a novel mammalian protein expression system, followed by SELEX-Seq, was used to identify a GU-rich RBM38 binding motif. Lastly, using a tethering assay, we determined that RBM38 can directly activate splicing when recruited to a downstream intron. Together, our data support the role of RBM38 in regulating alternative splicing during erythroid differentiation.
PMID: 24250749 [PubMed - in process]
Plerixafor in the treatment of stem cell mobilization failure; first experience in iran.
Iran J Pharm Res. 2013;12(Suppl):189-91
Authors: Mehdizadeh M, Hajifathali A, Tabarraee M, Tavakoli-Ardakani M
High-dose chemotherapy and autologous stem cell transplantation (SCT) have become an effective care for many patients with hematological malignancies. Harvesting the stem cells is one the most important parts of SCT. The two most commonly used mobilization regimens are the use of granulocyte colony-stimulating factor (G-CSF) or G-CSF plus chemotherapy. However, about 10-30% of patients are unable to collect enough cells to support HSCT due to previous chemotherapies, radiation, marrow involvement or fibrosis. In multiple myeloma patients, it is hard to collect enough stem cells when the bone marrow is extensively involved. Plerixafor has emerged as a novel mobilizing agent and its efficacy has been shown in two phase III studies. Considering the importance of autologous SCT in patients with multiple myeloma, we report the first successful Iranian experience at Tehran Taleghani bone marrow transplantation center using plerixafor to mobilize stem cells in a patient with refractory multiple myeloma with extensive bone marrow involvement who failed mobilization with G-CSF.
PMID: 24250688 [PubMed]
Evaluation of an Aqueous-Ethanolic Extract from Rosmarinus officinalis (Rosemary) for its Activity on the Hormonal and Cellular Function of Testes in Adult Male Rat.
Iran J Pharm Res. 2013;12(2):445-51
Authors: Heidari-Vala H, Ebrahimi Hariry R, Sadeghi MR, Akhondi MM, Ghaffari Novin M, Heidari M
Rosmarinus officinalis has been used in traditional medicine extensively. This study evaluated the hormonal and cellular effects of Rosmarinus officinalis extract on testes of adult rats. Thirty male Wistar rats (in three groups) received 50 or 100 mg/Kg b.w of Rosmarinus officinalis extract (made from the plant's leaves, flower and stem) (treatment groups) and 10 mL/Kg b.w normal saline (control group) respectively, on a daily bases by gavage route for 60 days. Then, spermatological properties, histometric parameters and sperm dynamics, testis and body weight, testicular cell population and serum testosterone level were analyzed by an acceptable method. Results showed that the mean serum testosterone level was decreased significantly in both treatment groups (50 and 100 mg/Kg b.w) during the experiment time, compared with control group (p < 0.05). However, Rosmarinus officinalis did not change the total count, motility and viability of sperm. In addition, Rosmarinus officinalis at both doses did not change body and testes weight and their ratio. Furthermore, Rosmarinus officinalis increased the number of Spermatogonia at both doses, Spermatocyte at doses of 50 mg/Kg b.w, Leydig cell and Spermatid at dose of 100 mg/Kg b.w significantly (p < 0.05). Rosmarinus officinalis did not significantly affect the number of Spermatozoid and Sertoli cells. In conclusion, it seems that Rosmarinus officinalis may have some hormonal and cellular effects on the testes which can contribute the spermatogenesis process in rat. Rosmarinus officinalis may have antiandrogenic effect potentially indicating the possibility of developing herbal male contraceptive.
PMID: 24250620 [PubMed]
Biotechnological Approach to Evaluate the Immunomodulatory Activity of Ethanolic Extract of Tinospora cordifolia Stem (Mango Plant Climber).
Iran J Pharm Res. 2012;11(3):863-72
Authors: Aher V, Kumar Wahi A
The present study was designed to investigate the immunomodulatory activity of the ethanolic extract of Tinospora cordifolia (Family: Menispermaceae) stem (climbing shrub, mango plant) at cellular level. For antioxidant study, the liver mitochondria were separated and the concentration of enzymes like lipid peroxidation (LPO), reduced glutathione (GSH), catalase (CAT) and superoxide Dismutase (SOD) were estimated; melatonin secretion characterization was carried out through SDS-PAGE. The spleen lymphocyte proliferation assay was performed through measuring its optical density at 570 nm using Elisa Reader. The cytokines viz. IL-2, IL-10 and TNF-α expression in spleen cells were determined through Real Time PCR. Tinospora cordifolia (Tc) ethanolic extract (100 mg/Kg/p.o.) increased the level of liver mitochondrial enzymes like GSH, CAT and SOD but decreased the level of LPO in liver as compared to the vehicle, SRBC and cyclophosphamide-treated groups. The secretion of melatonin via pineal gland was enhanced with Tc treatment. The extract also increased the spleen lymphocyte proliferation. In RT-PCR analysis, the expression of cytokines viz. IL-2, IL-10 and TNF-α was more in Tc-treated animals than vehicle and cyclophosphamide treatment. Hence, the study confirms the immunomodulatory activity of Tc stem through altering the concentration of antioxidant enzymes, increasing T and B cells and antibody which play an important role in immunity, enhancing the concentration of melatonin in pineal gland and increasing the level of cytokines like IL-2, IL-10 and TNF-α which plays an important role in immunity.
PMID: 24250513 [PubMed]
Glandular Trichomes and Essential Oil of Thymus quinquecostatus.
Authors: Jia P, Liu H, Gao T, Xin H
The distribution and types of glandular trichomes and essential oil chemistry of Thymus quinquecostatus were studied. The glandular trichomes are distributed on the surface of stem, leaf, rachis, calyx and corolla, except petiole, pistil and stamen. Three morphologically distinct types of glandular trichomes are described. Peltate trichomes, consisting of a basal cell, a stalk cell and a 12-celled head, are distributed on the stem, leaf, corolla and outer side of calyx. Capitate trichomes, consisting of a unicellular base, a 1-2-celled stalk and a unicellular head, are distributed more diffusely than peltate ones, existing on stem, leaf, rachis and calyx. Digitiform trichomes are just distributed on the outer side of corolla, consisting of 1 basal cell, 3 stalk cells and 1 head cell. All three types of glandular trichomes can secrete essential oil, and in small capitate trichomes of rachis, all peltate trichomes and digitiform trichomes, essential oil is stored in a large subcuticular space, released by cuticle rupture, whereas, in other capitate trichomes, essential oil crosses the thin cuticle. The essential oil of T. quinquecostatus is yellow, and its content is highest in the growth period. 68 constituents were identified in the essential oils. The main constituent is linalool.
PMID: 24250266 [PubMed - in process]
Cells Isolated from Human Periapical Cysts Express Mesenchymal Stem Cell-like Properties.
Int J Biol Sci. 2013;9(10):1070-8
Authors: Marrelli M, Paduano F, Tatullo M
We provide a detailed description of mesenchymal stem cells (MSCs) isolated from human periapical cysts, which we have termed hPCy-MSCs. These cells have a fibroblast-like shape and adhere to tissue culture plastic surfaces. hPCy-MSCs possess high proliferative potential and self-renewal capacity properties. We characterised the immunophenotype of hPCy-MSCs (CD73(+), CD90(+), CD105(+), CD13(+), CD29(+), CD44(+), CD45(-), STRO-1(+), CD146(+)) by flow cytometry and immunofluorescence. hPCy-MSCs possess the potential to differentiate into osteoblast- and adipocyte-like cells in vitro. Multi-potentiality was evaluated with culture-specific staining and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis for osteo/odontogenic and adipogenic markers. This is the first report to indicate that human periapical cysts contain cells with MSC-like properties. Taken together, our findings indicate that human periapical cysts could be a rich source of MSCs.
PMID: 24250252 [PubMed - in process]
The Hedgehog inhibitor cyclopamine antagonizes chemoresistance of breast cancer cells.
Onco Targets Ther. 2013;6:1643-7
Authors: Chai F, Zhou J, Chen C, Xie S, Chen X, Su P, Shi J
Chemoresistance of cancer cells has been a severe problem in multiple types of cancers. One possibility is to combine different drugs with chemotherapy for improved efficacy. Cyclopamine blocks Hedgehog signaling by antagonizing Smo function, which induces tumor apoptosis. Here, we show that the combined use of cyclopamine and paclitaxel (chemotherapy drugs) was able to induce breast cancer cell apoptosis both in vivo and in vitro. The results suggest that Hedgehog signaling is a prospective drug target for chemoresistant cancer cells.
PMID: 24250231 [PubMed]
Primary systemic amyloidosis of tongue with chondroid metaplasia.
J Oral Maxillofac Pathol. 2013 May;17(2):266-8
Authors: Vasudevan JA, Somanathan T, Patil SA, Kattoor J
Amyloid is a pathologic proteinaceous substance deposited between cells in various tissues in a variety of clinical conditions. We report a case of amyloidosis of tongue with extensive chondroid metaplasia diagnosed on incisional biopsy in a multiple myeloma patient, who underwent autologous peripheral blood stem cell transplant for the same in 2010 and now presented with disease relapse after 2 years.
PMID: 24250091 [PubMed]
Study of immunohistochemical demonstration of Bcl-2 protein in ameloblastoma and keratocystic odontogenic tumor.
J Oral Maxillofac Pathol. 2013 May;17(2):176-80
Authors: Sindura C, Babu C, Mysorekar V, Kumar V
BACKGROUND: The Bcl-2 (B-cell lymphoma) gene product also known as apoptotic inhibitor is expressed in many normal and tumor tissues. This Bcl-2 gene protects the cell by blocking postmitotic differentiation from apoptosis, thus maintaining the stem cell pool.
OBJECTIVE: To study the expression of Bcl-2 protein in ameloblastoma and keratocystic odontogenic tumor (KCOT) to determine their apoptotic behaviors and to analyze biological nature of KCOT, which has higher proliferative potential and aggressive clinical behavior like odontogenic tumors.
MATERIALS AND METHODS: Formalin-fixed paraffin sections of ameloblastoma (n = 20) and KCOT (n = 20) are considered for immunohistochemical analysis using monoclonal antibody against antihuman Bcl-2 oncoprotein. Lymphomas (n = 3) were used as controls.
STATISTICAL ANALYSIS: The statistical analysis was performed using software package of social science version 16. The data were analyzed using Chi-square test and Student's t test. In all the above tests, P < 0.05 was accepted as statistically significant.
RESULTS: The positive ratio of Bcl-2 was 85% (17/20) in ameloblastoma, 85% (17/20) in KCOT and 100% (3/3) in lymphomas. Bcl-2 was expressed in peripheral cells and few scattered cells of stellate reticulum in ameloblastoma. KCOT showed strong positivity for Bcl-2 mainly in the basal layer.
INTERPRETATION AND CONCLUSION: The present study demonstrates the aggressive nature of KCOT and intrinsic growth potential of its lining epithelium. This study clearly demonstrates that KCOT like ameloblastoma demonstrates aggressive clinical and noticeable invasive behavior. Therefore, it is now considered as no longer a developmental cyst but as odontogenic tumor.
PMID: 24250074 [PubMed]
Mesenchymal stem cells administered in the early phase of tumorigenesis inhibit colorectal tumor development in rats.
J Clin Biochem Nutr. 2013 Nov;53(3):170-5
Authors: Katsuno T, Ochi M, Tominaga K, Tanaka F, Sogawa M, Tanigawa T, Yamagami H, Shiba M, Watanabe K, Watanabe T, Fujiwara Y, Arakawa T
To investigate the differences between the effects of mesenchymal stem cells (MSCs) administered in the early and late phases of tumorigenesis, MSCs were isolated from bone marrow and colorectal tumors were produced by exposing 7-week-old F344 rats to 1,2-dimethylhydrazine and dextran sulfate sodium. We evaluated tumor number and volume (week 25), MSC localization, number of aberrant crypt foci (ACF), transforming growth factor (TGF)-β1 protein levels in the rectum after administration of MSCs (week 5 or 15), and the effects of MSC-conditioned medium on ACL15 cell proliferation. Administered MSCs labeled with PKH26 were observed in the rectum. Administered MSCs in the early phase (week 5) before tumor occurrence (week 12) significantly decreased tumor number and volume (1.5 vs 4 and 21 mm(3) vs 170 mm(3); p<0.01), but not administered MSCs in the late phase (week 15). Administered MSCs in the early phase reduced ACF number on days 14 and 35 (1.9 vs 4.1 and 3.7 vs 7.3; p<0.01). Rectal TGF-β1 increased 1.3 fold on day 3, and MSC-conditioned medium containing TGF-β1 abundantly inhibited ACL15 cell proliferation. MSCs administered in the early phase but not late phase inhibited colorectal tumor development in a rat model.
PMID: 24249972 [PubMed]
Growth Properties of Cardiac Stem Cells Are a Novel Biomarker of Patients' Outcome After Coronary Bypass Surgery.
Circulation. 2013 Nov 18;
Authors: D'Amario D, Leone AM, Iaconelli A, Luciani N, Gaudino M, Kannappan R, Manchi M, Severino A, Shin SH, Graziani F, Biasillo G, Macchione A, Smaldone C, De Maria GL, Cellini C, Siracusano A, Ottaviani L, Massetti M, Goichberg P, Leri A, Anversa P, Crea F
BACKGROUND: The efficacy of bypass surgery in patients with ischemic cardiomyopathy is not easily predictable; preoperative clinical conditions may be similar, but the outcome may differ significantly. We hypothesized that the growth reserve of cardiac stem cells (CSCs) and circulating cytokines promoting CSC activation are critical determinants of ventricular remodeling in this patient population.
METHODS AND RESULTS: To document the growth kinetics of CSCs, population-doubling time, telomere length, telomerase activity, and insulin-like growth factor-1 receptor expression were measured in CSCs isolated from 38 patients undergoing bypass surgery. Additionally, the blood levels of insulin-like growth factor-1, hepatocyte growth factor, and vascular endothelial growth factor were evaluated. The variables of CSC growth were expressed as a function of the changes in wall thickness, chamber diameter and volume, ventricular mass-to-chamber volume ratio, and ejection fraction, before and 12 months after surgery. A high correlation was found between indices of CSC function and cardiac anatomy. Negative ventricular remodeling was not observed if CSCs retained a significant growth reserve. The high concentration of insulin-like growth factor-1 systemically pointed to the insulin-like growth factor-1-insulin-like growth factor-1 receptor system as a major player in the adaptive response of the myocardium. hepatocyte growth factor, a mediator of CSC migration, was also high in these patients preoperatively, as was vascular endothelial growth factor, possibly reflecting the vascular growth needed before bypass surgery. Conversely, a decline in CSC growth was coupled with wall thinning, chamber dilation, and depressed ejection fraction.
CONCLUSIONS: The telomere-telomerase axis, population-doubling time, and insulin-like growth factor-1 receptor expression in CSCs, together with a high circulating level of insulin-like growth factor-1, represent a novel biomarker able to predict the evolution of ischemic cardiomyopathy following revascularization.
PMID: 24249720 [PubMed - as supplied by publisher]
Predicting the Future With Stem Cells.
Circulation. 2013 Nov 18;
Authors: Mohsin S, Wu JC, Sussman MA
PMID: 24249719 [PubMed - as supplied by publisher]
Mesenchymal stem cell response to conformal sputter deposited calcium phosphate thin films on nanostructured titanium surfaces.
J Biomed Mater Res A. 2013 Nov 1;
Authors: McCafferty MM, Burke GA, Meenan BJ
Biomaterial surfaces that can directly induce the osteogenic differentiation of mesenchymal stem cells (MSCs) present an exciting strategy for bone tissue engineering and offers significant benefits for improving the repair or replacement of damaged or lost bone tissue. In this study, titanium nanostructures with distinctive topographical features were produced by radio frequency magnetron sputtering. The response of MSCs to the nanostructured titanium (Ti) surfaces before and after augmentation by a sputter deposited calcium phosphate (CaP) coating has been investigated. The sputtered CaP has the characteristics of a calcium enriched hydroxyapatite surface layer, as determined by X-ray photoelectron spectroscopy and X-ray diffraction studies. The sputter deposited Ti has a polycrystalline surface morphology, as confirmed by atomic force microscopy, and CaP layers deposited thereon (TiCaP) conform to this topography. The effects of these surfaces on MSC focal adhesion formation, actin cytoskeleton organization and Runx2 gene expression were examined. The Ti and TiCaP surfaces were found to promote changes in MSC morphology and adhesion known to be associated with subsequent downstream osteogenic differentiation; however, the equivalent events were not as pronounced on the CaP surface. A significant increase in Runx2 expression was observed for CaP compared to Ti, but no such difference was seen between either Ti and TiCaP, nor CaP and TiCaP. Importantly, the Ti surface engendered the expected contribution of nanoscale features to the MSC response; moreover, the CaP layer when used in combination with this topography has been found to cause no adverse effects in respect of MSC behavior. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
PMID: 24249697 [PubMed - as supplied by publisher]
Interaction of delta-like 1 homolog (Drosophila) with prohibitins and its impact on tumor cell clonogenicity.
Mol Cancer Res. 2013 Nov 18;
Authors: Begum A, Lin Q, Yu C, Kim Y, Yun Z
Cancer stem cell characteristics, especially their self-renewal and clonogenic potentials, play an essential role in malignant progression and response to anti-cancer therapies. Currently, it remains largely unknown what pathways are involved in the regulation of cancer cell stemness and differentiation. Previously, we found that delta-like 1 homolog (Drosophila) or DLK1, a developmentally regulated gene, plays a critical role in regulation of differentiation, self-renewal, and tumorigenic growth of neuroblastoma cells. Here, we show that DLK1 specifically interacts with the prohibitin 1 (PHB1) and PHB2, two closely related genes with pleiotropic functions including regulation of mitochondrial function and gene transcription. DLK1 interacts with the PHB1-PHB2 complex via its cytoplasmic domain and regulates mitochondrial functions including mitochondrial membrane potential and production of reactive oxygen species (ROS). We have further found that PHB1 and especially PHB2 regulate cancer cell self-renewal as well as their clonogenic potential. Hence, the DLK1-PHB interaction constitutes a new signaling pathway that maintains clonogenicity and self-renewal potential of cancer cells. Implications: This study provides a new mechanistic insight into the regulation of the stem cell characteristics of cancer cells.
PMID: 24249679 [PubMed - as supplied by publisher]
Skin progenitor cells contribute to bleomycin-induced skin fibrosis.
Arthritis Rheum. 2013 Nov 18;
Authors: Liu S, Herault Y, Pavlovic G, Leask A
BACKGROUND: The origin of the cells that contribute to skin fibrosis is unclear. Herein, we assess the contribution of sox2-expressing skin progenitor cells to bleomycin-induced skin scleroderma.
METHODS: We subject wild-type mice and mice in which CCN2 is deleted in sox2-expressing cells to bleomycin-induced skin scleroderma. We also conduct lineage tracing analysis to assess whether cells expressing sox2 are recruited to fibrotic lesions in response to bleomycin-induced scleroderma.
RESULTS: In response to bleomycin, sox2-positive/α-smooth muscle actin-positive cells are recruited to fibrotic tissue. Conditional CCN2 knockout mice in which CCN2 is deleted in sox2-expressing cells exhibit resistance to bleomycin-induced skin fibrosis. Collectively, these results indicate that CCN2 is required for the recruitment of progenitor cells and that CCN2-expressing progenitor cells are essential for bleomycin-induced skin fibrosis. Lineage tracing using mice in which a tamoxifen-dependent cre recombinase is expressed under the control of the sox2 promoter confirm that progenitor cells are recruited to the fibrotic lesion in response to bleomycin, but not in CCN2-knockout mice. CCN2 is required for the ability of serum to induce α-smooth muscle actin expression in skin progenitor cells.
CONCLUSION: Sox2-positive skin progenitor cells are required for bleomycin-induced skin fibrosis and CCN2 is required for their recruitment to the fibrotic lesion. Targeting stem cell recruitment or CCN2 may therefore represent useful targets in combating fibrotic skin disease. © 2013 American College of Rheumatology.
PMID: 24249432 [PubMed - as supplied by publisher]
Symplast domains in extrastelar tissues of Egeria densa Planch.
Planta. 1985 Jan;163(1):9-19
Authors: Erwee MG, Goodwin PB
A set of hydrophilic fluorescent dyes of known molecular weight has been used to determine the molecular exclusion limit and the extent of apical, epidermal and cortical symplasts in the root, stem and leaf of Egeria densa. These dyes are unable to pass the plasmalemma, so that any cell-to-cell movement of injected dye must occur via the symplast. The shoot-apex symplast has a high molecular exclusion limit, excluding dyes with a molecular weight of 749 dalton (fluorescein hexaglycine) and greater but allowing dyes of up to 665 dalton (fluorescein diglutamic acid) to pass. The leaf epidermal symplast is similar to that in the apex: fluorescein pentaglycine (674 dalton) moves to a limited extent, but fluorescein hexaglycine is immobile. Stem and root epidermal cells have a lower molecular exclusion limit, only the dye 6-carboxyfluorescein (376 dalton) is able to move from cell-to-cell. Cortical and epidermal tissues in both the stem and the root have similar symplast permeabilities. However, a barrier to dye (6-carboxyfluorescein) movement is found between the epidermis and the cortex in both organs. Barriers are also found at the nodes between expanded internodes. The stem barriers are not found in the unexpanded nodes near the shoot tip; apparently they are formed early during internode expansion. In the root tip, a barrier to the movement of dye is found between the root cap and the remainder of the root. Plasmodesmata are found linking all cell types studied, even cells where barriers to dye movement occur. Thus, the plant, far from being one uniform symplast, consists of a large number of symplast domains, which may or may not differ in molecular exclusion limit.
PMID: 24249262 [PubMed - in process]
Clinical application of circulating tumor cells in breast cancer.
Cell Oncol (Dordr). 2013 Nov 19;
Authors: Broersen LH, van Pelt GW, Tollenaar RA, Mesker WE
Circulating tumor cells (CTCs) play a major role in the metastatic spread of breast cancer. CTC detection has proven to be an important parameter for predicting progression free and overall survival. Collection of CTCs is minimally invasive and can be performed more often than disseminated tumor cell (DTC) collection from bone marrow, thus providing a real-time "liquid biopsy". In this review, the most important techniques for enrichment and detection of CTCs are discussed for clinical application in low and higher staged breast cancer, as well as the genetic and molecular characterization of CTCs. For CTCs, the use of immunology-based enrichment techniques with multiple antibodies is recommended in a clinical setting, as well as the use of cytometric detection techniques, combined with RT-PCR for confirmation. Special attention is given to the value of cancer stem cell (CSC) activity, which may be the main cause of ineffectiveness of the control over metastatic lesions due to intratumor heterogeneity. Accumulating information on CSCs offers new paradigms to generate effective targets for the treatment of metastatic disease. Genetic and molecular characterization of CTCs has potential to stratify patients for optimal personalized treatment regimens. CTCs can be used for monitoring patients during treatment schedules.
PMID: 24249155 [PubMed - as supplied by publisher]
Humanized mice: novel model for studying mechanisms of human immune-based therapies.
Immunol Res. 2013 Nov 19;
Authors: Gonzalez L, Strbo N, Podack ER
The lack of relevant animal models is the major bottleneck for understanding human immunology and immunopathology. In the last few years, a novel model of humanized mouse has been successfully employed to investigate some of the most critical questions in human immunology. We have set up and tested in our laboratory the latest technology for generating mice with a human immune system by reconstituting newborn immunodeficient NOD/SCID-γ c (-/-) mice with human fetal liver-derived hematopoietic stem cells. These humanized mice have been deemed most competent as human models in a thorough comparative study with other humanized mouse technologies. Lymphocytes in these mice are of human origin while other hematopoietic cells are chimeric, partly of mouse and partly of human origin. We demonstrate that human CD8 T lymphocytes in humanized mice are fully responsive to our novel cell-based secreted heat shock protein gp96(HIV)-Ig vaccine. We also show that the gp96(HIV)-Ig vaccine induces powerful mucosal immune responses in the rectum and the vagina, which are thought to be required for protection from HIV infection. We posit the hypothesis that vaccine approaches tested in humanized mouse models can generate data rapidly, economically and with great flexibility (genetic manipulations are possible), to be subsequently tested in larger nonhuman primate models and humans.
PMID: 24248605 [PubMed - as supplied by publisher]
Effects of octylphenol on the expression of cell cycle-related genes and the growth of mesenchymal stem cells derived from human umbilical cord blood.
Int J Mol Med. 2013 Nov 14;
Authors: Lee HR, Kim TH, Choi KJ, Choi KC
Umbilical cord blood (UCB) is defined as blood that exists in the placenta and in the attached umbilical cord following childbirth. Cord blood is now used for research purposes as it contains mesenchymal stem cells (MSCs), multipotent stromal cells which have the ability to differentiate into a variety of cell types. Among endocrine disrupting chemicals (EDCs), octylphenol (OP) is one of the alkylphenols, which are widely used industrial chemicals; these chemicals cause a number of serious side-effects, such as reproductive abnormalities. In this study, we isolated human MSCs from UCB and demonstrate that cultured MSCs express the surface marker, CD34, but not CD105. We further examined the effects of OP on human UCB-derived MSCs following exposure to OP by cell proliferation assay, semi-quantitative RT-PCR and western blot analysis. The results revealed that the transcriptional and translational levels of cyclin D1 were increased, while the levels of p21 were suppressed in the MSCs treated with OP compared with the negative controls. This collapse of the regulation of the cell cycle may directly stimulate the growth of the MSCs under culture conditions. The results from the present study provide further insight into the effects of common EDCs on MSCs derived from human UCB. However, further studies are required to identify the signaling pathways which mediate the effects of EDCs on MSCs.
PMID: 24248536 [PubMed - as supplied by publisher]
High efficiency Agrobacterium-mediated transformation of Lycopersicon based on conditions favorable for regeneration.
Plant Cell Rep. 1987 Apr;6(2):105-8
Authors: Chyi YS, Phillips GC
A successful Agrobacterium-mediated transformation system involving a disarmed Ti plasmid is composed of two stages: transformation of cells and recovery of transformed plants. A tissue transformation system with 34% efficiency was developed using stem segments of the interspecific tomato hybrid Lycopersicon esculentum × L. pennellii. This transformation system emphasizes three factors favoring the recovery of transformed plants: 1) promotion of cell division activity at the inoculation site with kinetin in the incubation medium, 2) promotion of adventitious bud initiation by using organized tissue explants in culture, and 3) application of selection at the shoot development stage of adventitious regeneration.
PMID: 24248488 [PubMed - in process]
Clonal variability and light induction of betalain synthesis in red beet cell cultures.
Plant Cell Rep. 1987 Feb;6(1):27-30
Authors: Girod PA, Zryd JP
When calli from a green habituated cell culture of red beet (Beta vulgaris L.) are transfered from dim-light to high-light intensity, red colored spots appear on the surface. Not all cells express the pigmented phenotype, giving rise to variegated patches. The pattern of patch formation is different from one callus to another, although all calluses stem from the same original clone. This clonal variability is an intrinsic property of the tissue and is not affected by light which is only needed for the induction of pigment synthesis, and therefore acts as a revealing factor.
PMID: 24248443 [PubMed - in process]
A fully defined and scalable 3D culture system for human pluripotent stem cell expansion and differentiation.
Proc Natl Acad Sci U S A. 2013 Nov 18;
Authors: Lei Y, Schaffer DV
Human pluripotent stem cells (hPSCs), including human embryonic stem cells and induced pluripotent stem cells, are promising for numerous biomedical applications, such as cell replacement therapies, tissue and whole-organ engineering, and high-throughput pharmacology and toxicology screening. Each of these applications requires large numbers of cells of high quality; however, the scalable expansion and differentiation of hPSCs, especially for clinical utilization, remains a challenge. We report a simple, defined, efficient, scalable, and good manufacturing practice-compatible 3D culture system for hPSC expansion and differentiation. It employs a thermoresponsive hydrogel that combines easy manipulation and completely defined conditions, free of any human- or animal-derived factors, and entailing only recombinant protein factors. Under an optimized protocol, the 3D system enables long-term, serial expansion of multiple hPSCs lines with a high expansion rate (∼20-fold per 5-d passage, for a 10(72)-fold expansion over 280 d), yield (∼2.0 × 10(7) cells per mL of hydrogel), and purity (∼95% Oct4+), even with single-cell inoculation, all of which offer considerable advantages relative to current approaches. Moreover, the system enabled 3D directed differentiation of hPSCs into multiple lineages, including dopaminergic neuron progenitors with a yield of ∼8 × 10(7) dopaminergic progenitors per mL of hydrogel and ∼80-fold expansion by the end of a 15-d derivation. This versatile system may be useful at numerous scales, from basic biological investigation to clinical development.
PMID: 24248365 [PubMed - as supplied by publisher]
Polyamine delivery as a tool to modulate stem cell differentiation in skeletal tissue engineering.
Amino Acids. 2013 Nov 19;
Authors: Borzì RM, Guidotti S, Minguzzi M, Facchini A, Platano D, Trisolino G, Filardo G, Cetrullo S, D'Adamo S, Stefanelli C, Facchini A, Flamigni F
The first step in skeleton development is the condensation of mesenchymal precursors followed by any of two different types of ossification, depending on the type of bone segment: in intramembranous ossification, the bone is deposed directly in the mesenchymal anlagen, whereas in endochondral ossification, the bone is deposed onto a template of cartilage that is subsequently substituted by bone. Polyamines and polyamine-related enzymes have been implicated in bone development as global regulators of the transcriptional and translational activity of stem cells and pivotal transcription factors. Therefore, it is tempting to investigate their use as a tool to improve regenerative medicine strategies in orthopedics. Growing evidence in vitro suggests a role for polyamines in enhancing differentiation in both adult stem cells and differentiated chondrocytes. Adipose-derived stem cells have recently proved to be a convenient alternative to bone marrow stromal cells, due to their easy accessibility and the high frequency of stem cell precursors per volume unit. State-of-the-art "prolotherapy" approaches for skeleton regeneration include the use of adipose-derived stem cells and platelet concentrates, such as platelet-rich plasma (PRP). Besides several growth factors, PRP also contains polyamines in the micromolar range, which may also exert an anti-apoptotic effect, thus helping to explain the efficacy of PRP in enhancing osteogenesis in vitro and in vivo. On the other hand, spermidine and spermine are both able to enhance hypertrophy and terminal differentiation of chondrocytes and therefore appear to be inducers of endochondral ossification. Finally, the peculiar activity of spermidine as an inducer of autophagy suggests the possibility of exploiting its use to enhance this cytoprotective mechanism to counteract the degenerative changes underlying either the aging or degenerative diseases that affect bone or cartilage.
PMID: 24248311 [PubMed - as supplied by publisher]
Production of the triterpenoid quassin in callus and cell suspension cultures of Picrasma quassioides Bennett.
Plant Cell Rep. 1986 Oct;5(5):356-9
Authors: Scragg AH, Allan EJ
Plant cell and suspension cultures have been established from stem cuttings of Picrasma quassioides Bennett. The effect of 244 different types/concentrations of plant growth regulators on growth and quassin accumulation in callus tissue was investigated. Best growth, in terms of wet/dry weight after four weeks growth, was obtained on B5 media supplemented with 2% glucose, 10% coconut milk, 0.5 mg.l(-1) zeatin riboside and 1.5 mg.l(-1) IBA. The highest yields of quassin (0.014-0.018%) were detected on this same media supplemented with 1.0 mg.l(-1) IBA and varying concentrations of zeatin riboside. Suspension cultures were easily established on B5 media supplemented with 2% glucose, 1.0 mg.l(-1) 2,4-D and 0.5 mg.l(-1) kinetin. The carbon source had a marked effect on quassin accumulation with 0.32% quassin being detected when cells were grown in 2% galactose. This is comparable to the highest reported quassin yield for the whole plant.
PMID: 24248298 [PubMed - in process]
Cancer stem cell characteristics, ALDH1 expression in the invasive front of nasopharyngeal carcinoma.
Virchows Arch. 2013 Nov 19;
Authors: Luo WR, Yao KT
The invasive tumor front underlies the biological aggressiveness and epithelial-mesenchymal transition (EMT) in various human malignances. However, the molecular and biological characteristics of invasive tumor front in NPC have rarely been described. Additionally, the features of cancer stem cells (CSCs) in the invasive front of tumors and its correlation with EMT also remain elusive. Our study was to investigate the expression of CSCs marker aldehyde dehydrogenase 1 (ALDH1) in the invasive front of nasopharyngeal carcinoma (NPC) and its clinical significance. Immunohistochemistry was mainly used to detect ALDH1 expression in the invasive front of NPC. The relationship between ALDH1 expression and EMT-associated markers was also examined. ALDH1 expression in the invasive front correlated strongly with lymphatic invasion (p < 0.001), T classification (p = 0.001), M classification (p < 0.001), clinical stage (p < 0.001), and local recurrence (p = 0.008). ALDH1 overexpression in the invasive front contributed to worse survival of NPC, particularly in patients with early stage (T1-T2 or N0-N1) (p < 0.001 and p = 0.002, respectively), though it was not an independent prognostic factor (p = 0.196). Furthermore, in the invasive front of NPC, ALDH1 expression correlated significantly with EMT-related biomarkers E-cadherin (p = 0.026), Vimentin (p < 0.001), Periostin (p < 0.001), and Snail (p < 0.001), but not with β-catenin (p = 0.143). Our findings demonstrate first that ALDH1 expression in the invasive front links closely with EMT characteristics and tumor aggressiveness, which might provide a useful prognostic marker for NPC patients.
PMID: 24248285 [PubMed - as supplied by publisher]
Basic fibroblast growth factor increases the transplantation‑mediated therapeutic effect of bone mesenchymal stem cells following traumatic brain injury.
Mol Med Rep. 2013 Nov 15;
Authors: Liu Y, Yi XC, Guo G, Long QF, Wang XA, Zhong J, Liu WP, Fei Z, Wang DM, Liu J
Basic fibroblast growth factor (bFGF) has proven useful for neural stem and progenitor cells during the transplantation‑mediated therapeutic effect of bone mesenchymal stem cells (BMSCs). Endogenous bFGF expression levels increase during brain development and gradually diminish with aging. To date, few studies have been conducted on exogenous bFGF promoting BMSC transplantation‑mediated functional recovery in adult rats following traumatic brain injury (TBI). The results of the present study showed that BMSCs in the TBI cortex and dentate gyrus showed differentiation along the glial and neuronal lines, which are possibly enhanced by bFGF. The neuronal differentiation rate was not consistent with neurological functional recovery rate over time. bFGF may promote the transplantation‑mediated therapeutic effect of BMSCs more significantly and rapidly in rats following TBI, with a small proportion of differentiated neurons. In conclusion, exogenous bFGF functions as a booster of the transplantation‑mediated therapeutic effect of BMSCs following TBI.
PMID: 24248266 [PubMed - as supplied by publisher]
Ganetespib blocks HIF-1 activity and inhibits tumor growth, vascularization, stem cell maintenance, invasion, and metastasis in orthotopic mouse models of triple-negative breast cancer.
J Mol Med (Berl). 2013 Nov 20;
Authors: Xiang L, Gilkes DM, Chaturvedi P, Luo W, Hu H, Takano N, Liang H, Semenza GL
Targeted therapy against triple-negative breast cancers, which lack expression of the estrogen, progesterone, and HER2 receptors, is not available and the overall response to cytotoxic chemotherapy is poor. One of the molecular hallmarks of triple-negative breast cancers is increased expression of genes that are transcriptionally activated by hypoxia-inducible factors (HIFs), which are implicated in many critical aspects of cancer progression including metabolism, angiogenesis, invasion, metastasis, and stem cell maintenance. Ganetespib is a second-generation inhibitor of heat shock protein 90 (HSP90), a molecular chaperone that is essential for the stability and function of multiple client proteins in cancer cells including HIF-1α. In this study, human MDA-MB-231 and MDA-MB-435 triple-negative breast cancer cells were injected into the mammary fat pad of immunodeficient mice that received weekly intravenous injections of ganetespib or vehicle following the development of palpable tumors. Ganetespib treatment markedly impaired primary tumor growth and vascularization, and eliminated local tissue invasion and distant metastasis to regional lymph nodes and lungs. Ganetespib treatment also significantly reduced the number of Aldefluor-positive cancer stem cells in the primary tumor. Primary tumors of ganetespib-treated mice had significantly reduced levels of HIF-1α (but not HIF-2α) protein and of HIF-1 target gene mRNAs encoding proteins that play key roles in angiogenesis, metabolism, invasion, and metastasis, thereby providing a molecular basis for observed effects of the drug on the growth and metastasis of triple-negative breast cancer.
KEY MESSAGES: Triple-negative breast cancers (TNBCs) respond poorly to available chemotherapy. TNBCs overexpress genes regulated by hypoxia-inducible factors (HIFs). Ganetespib induces degradation of HSP90 client proteins, including HIF-1α. Ganetespib inhibited TNBC orthotopic tumor growth, invasion, and metastasis. Ganetespib inhibited expression of HIF-1 target genes involved in TNBC progression.
PMID: 24248265 [PubMed - as supplied by publisher]
Osmotic adjustment and the inhibition of leaf, root, stem and silk growth at low water potentials in maize.
Planta. 1985 Jul;164(4):540-9
Authors: Westgate ME, Boyer JS
The expansion growth of plant organs is inhibited at low water potentials (Ψ w), but the inhibition has not been compared in different organs of the same plant. Therefore, we determined elongation rates of the roots, stems, leaves, and styles (silks) of maize (Zea mays L.) as soil water was depleted. The Ψ w was measured in the region of cell expansion of each organ. The complicating effects of transpiration were avoided by making measurements at the end of the dark period when the air had been saturated with water vapor for 10 h and transpiration was less than 1% of the rate in the light. Growth was inhibited as the Ψ w in the region of cell expansion decreased in each organ. The Ψ w required to stop growth was-0.50,-0.75, and-1.00 MPa, in this order, in the stem, silks, and leaves. However, the roots grew at these Ψ w and ceased only when Ψ w was lower than-1.4 MPa. The osmotic potential decreased in each region of cell expansion and, in leaves, roots and stems, the decrease was sufficient to maintain turgor fully. In the silks, the decrease was less and turgor fell. In the mature tissue, the Ψ w of the stem, leaves and roots was similar to that of the soil when adequate water was supplied. This indicated that an equilibrium existed between these tissues, the vascular system, and the soil. At the same time, the Ψ w was lower in the expanding regions than in the mature tissues, indicating that there was a Ψ w disequilibrium between the growing tissue and the vascular system. The disequilibrium was interpreted as a Ψ w gradient for supplying water to the enlarging cells. When water was withheld, this gradient disappeared in the leaf because Ψ w decreased more in the xylem than in the soil, indicating that a high flow resistance had developed in the xylem. In the roots, the gradient did not decrease because vascular Ψ w changed about the same amount as the soil Ψ w. Therefore, the gradient in Ψ w favored water uptake by roots but not leaves at low Ψ w. The data show that expansion growth responds to low Ψ w differently in different growing regions of the plant. Because growth depends on the maintenance of turgor for extending the cell walls and the presence of Ψ w gradients for supplying water to the expanding cells, several factors could have been responsible for these differences. The decrease of turgor in the silks and the loss of the Ψ w gradient in the leaves probably contributed to the high sensitivity of these organs. In the leaves, the gradient loss was so complete that it would have prevented growth regardless of other changes. In the roots, the maintenance of turgor and Ψ w gradients probably allowed growth to continue. This difference in turgor and gradient maintenance could contribute to the increase in root/shoot ratios generally observed in water-limited conditions.
PMID: 24248230 [PubMed - in process]
Cytotoxic effects of acrylonitrile on human umbilical cord mesenchymal stem cells in vitro.
Mol Med Rep. 2013 Nov 15;
Authors: Sun X, Sun M, Xie Y, Zhai W, Zhu W, Ma R, Lu R, Xu W
The effects of acrylonitrile (ACN) on human umbilical cord mesenchymal stem cells (hUC‑MSCs) remain unknown. The proliferation, differentiation, clonogenicity and apoptosis effects of ACN and/or N‑acetyl‑L‑cysteine (NAC) on hUC‑MSCs were investigated. The results showed that although ACN at a concentration of 0.1 µg/ml did not affect proliferation or the morphology of hUC‑MSCs compared with the control, osteogenic differentiation and the positive rate of alkaline phosphatase staining in the experimental group were significantly lower compared with the control (P<0.01). All of the effects of ACN were counteracted using NAC, a typical antioxidant. Using a flow cytometry assay, it was observed that ACN induced apoptosis in hUC‑MSCs. The results indicated that the toxic effect produced by ACN on hUC‑MSCs is based on a redox mechanism.
PMID: 24248151 [PubMed - as supplied by publisher]
Transformation of Medicago by Agrobacterium mediated gene transfer.
Plant Cell Rep. 1986 Apr;5(2):97-100
Authors: Deak M, Kiss GB, Koncz C, Dudits D
Shoot segments of Medicago varia genotype A2 were co-cultivated with Agrobacterium tumefaciens strain bo42 carrying pGA471, a plasmid coding for the kanamycin resistant determinant as transferable positive selection marker in plant cells (An et al., 1985). Resistant plants were regenerated at high frequency from green calli developed on inoculated stem cuttings under kanamycin selection. DNA-DNA hybridization analysis showed the presence of the structural gene of the kanamycin resistant determinant in total DNA isolated from several independent transformants. All data presented clearly demonstrate the transfer, stable maintenance and functional expression of the kanamycin resistance marker in Medicago varia cells which retain their morphogenic property.
PMID: 24248043 [PubMed - in process]
Neurotrophin 3 Transduction Augments Remyelinating and Immunomodulatory Capacity of Neural Stem Cells.
Mol Ther. 2013 Oct 17;
Authors: Yang J, Yan Y, Xia Y, Kang T, Li X, Ciric B, Xu H, Rostami A, Zhang GX
Neural stem cells (NSCs) have therapeutic potential in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS); however, to date, their use has resulted in only limited clinical and pathological improvement. To enhance their therapeutic capacity, in the present study, we transduced bone marrow-derived NSCs (BM-NSCs) with neurotrophin 3 (NT-3), a potent neurotrophic factor that is both neuroprotective and immunomodulatory. We found that BM-NSCs transduced with NT-3 reduced central nervous system (CNS) inflammation and neurological deficits in ongoing EAE significantly more than conventional NSC therapy, and, in addition, had the following advantages: (i) enhanced BM-NSC proliferation and differentiation into oligodendrocytes and neurons, as well as inhibited differentiation into astrocytes, thus promoting remyelination and neuronal repopulation, and reducing astrogliosis; (ii) enhanced anti-inflammatory capacity of BM-NSCs, thus more effectively suppressing CNS inflammation and accelerating remyelination; (iii) the easy accessibility of BM-NSCs provides another advantage over brain-derived NSCs for MS therapy; and (iv) a novel Tet-on system we used enables efficient control of NT-3 expression. Thus, our study provides a novel approach to break the vicious inflammation-demyelination cycle, and could pave the way to an easily accessible and highly effective therapy for CNS inflammatory demyelination.Molecular Therapy (2013); doi:10.1038/mt.2013.241.
PMID: 24247929 [PubMed - as supplied by publisher]
Local control of hepatic phenotype with growth factor-encoded surfaces.
Integr Biol (Camb). 2013 Nov 19;
Authors: Patel D, Haque A, Jones CN, Tuleouva N, Foster E, Vu T, Reddi AH, Revzin A
The goal of the present study was to modulate the phenotype expression of hepatocytes in vitro on surfaces imprinted with growth factors (GFs). Hepatocyte growth factor (HGF) or transforming-growth factor-β1 (TGF-β1) were mixed with collagen (I) and robotically printed onto standard glass slides to create arrays of 300 μm or 500 μm diameter spots. Primary rat hepatocytes were seeded on top of the arrays, forming clusters corresponding in size to the underlying protein spots. The TGF-β1 spots appeared to downregulate markers of hepatic (epithelial) phenotype while upregulating expression of mesenchymal markers. Conversely, hepatocytes cultured on HGF spots maintained high level of epithelial markers. When hepatocytes were seeded onto alternating spots of HGF and TGF-β1, their phenotype was found to depend on center-to-center distance between the spots. At shorter distances cross-expression of epithelial and mesenchymal markers was observed while at distances exceeding 1.25 mm divergence of phenotypes, epithelial on HGF and mesenchymal on TGF-β was seen. Overall, our results demonstrate that GF-encoded surfaces can modulate phenotype within groups of cells cultured on the same surface. Given the importance of phenotype switching in development, fibrosis and cancer, this platform may be used to gain useful insights into the mechanisms of processes such as epithelial-to-mesenchymal transition or stem cell fate selections.
PMID: 24247788 [PubMed - as supplied by publisher]
Differentiation of human hair follicle stem cells into endothelial cells induced by vascular endothelial and basic fibroblast growth factors.
Mol Med Rep. 2013 Nov 14;
Authors: Xu ZC, Zhang Q, Li H
Hair follicle stem cells (HFSCs) possess powerful expansion and multi‑differentiation potential, properties that place them at the forefront of the field of tissue engineering and stem cell‑based therapy. The aim of the present study was to investigate the differentiation of human HFSCs (hHFSCs) into cells of an endothelial lineage. hHFSCs were expanded to the second passage in vitro and then induced by the addition of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) to the culture medium. The expression levels of endothelial cell (EC)‑related markers, including von Willebrand factor (vWF), vascular endothelial cadherin (VE)‑cadherin and cluster of differentiation (CD)31, were detected by immunofluorescence staining, flow cytometric analysis and reverse transcription‑polymerase chain reaction. The hHFSCs expressed vWF, VE‑cadherin and CD31 when exposed to a differentiation medium, similar to the markers expressed by the human umbilical vein ECs. More significantly, differentiated cells were also able to take up low‑density lipoprotein. The data of the present study demonstrated that an efficient strategy may be developed for differentiating hHFSCs into ECs by stimulation with VEGF and bFGF. Thus, hHFSCs represent a novel cell source for vascular tissue engineering and studies regarding the treatment of various forms of ischaemic vascular disease.
PMID: 24247660 [PubMed - as supplied by publisher]
Selenium improves stem cell potency by stimulating the proliferation and active migration of 3T3-L1 preadipocytes.
Int J Oncol. 2013 Nov 15;
Authors: Park SH, Kim JH, Nam SW, Kim BW, Kim GY, Kim WJ, Choi YH
Selenium is a trace nutrient element that protects cells against oxidative damage. In this study, the potential of selenium to improve stem cell potency through active proliferation and migration of 3T3-L1 preadipocytes was investigated, together with the underlying molecular mechanisms. The results indicated that selenium applied for 24 h stimulated cell proliferation up to 20% compared to untreated control cells. Selenium induced the expression of cyclin-dependent kinase (CDK) 1 and CDK2, which are known to regulate G2/M progression, and significantly downregulated the CDK inhibitors p21 and p27. Selenium also activated the expression of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, as well as extracellular signal-regulated kinase (ERK). Although LY294002, an inhibitor of PI3K, significantly inhibited the selenium-induced cell proliferation of the 3T3-L1 preadipocytes, PD98059, an inhibitor of ERK, did not affect selenium-induced active proliferation. These results clearly indicate that selenium stimulated cell proliferation through cell cycle progression and PI3K/Akt activation, but not through ERK activation. Furthermore, selenium increased 3T3-L1 cell migration, which was associated with the induction of matrix metalloproteinase (MMP)-2 and MMP-9. Taken together, the current findings suggest that selenium can stimulate stem cell potency by increasing the proliferation and active migration of 3T3-L1 cells.
PMID: 24247590 [PubMed - as supplied by publisher]
Transendocardial Mesenchymal Stem Cells and Mononuclear Bone Marrow Cells for Ischemic Cardiomyopathy: The TAC-HFT Randomized Trial.
JAMA. 2013 Nov 18;
Authors: Heldman AW, Difede DL, Fishman JE, Zambrano JP, Trachtenberg BH, Karantalis V, Mushtaq M, Williams AR, Suncion VY, McNiece IK, Ghersin E, Soto V, Lopera G, Miki R, Willens H, Hendel R, Mitrani R, Pattany P, Feigenbaum G, Oskouei B, Byrnes J, Lowery MH, Sierra J, Pujol MV, Delgado C, Gonzalez PJ, Rodriguez JE, Bagno LL, Rouy D, Altman P, Foo CW, da Silva J, Anderson E, Schwarz R, Mendizabal A, Hare JM
IMPORTANCE Whether culture-expanded mesenchymal stem cells or whole bone marrow mononuclear cells are safe and effective in chronic ischemic cardiomyopathy is controversial. OBJECTIVE To demonstrate the safety of transendocardial stem cell injection with autologous mesenchymal stem cells (MSCs) and bone marrow mononuclear cells (BMCs) in patients with ischemic cardiomyopathy. DESIGN, SETTING, AND PATIENTS A phase 1 and 2 randomized, blinded, placebo-controlled study involving 65 patients with ischemic cardiomyopathy and left ventricular (LV) ejection fraction less than 50% (September 1, 2009-July 12, 2013). The study compared injection of MSCs (n=19) with placebo (n = 11) and BMCs (n = 19) with placebo (n = 10), with 1 year of follow-up. INTERVENTIONS Injections in 10 LV sites with an infusion catheter. MAIN OUTCOMES AND MEASURES Treatment-emergent 30-day serious adverse event rate defined as a composite of death, myocardial infarction, stroke, hospitalization for worsening heart failure, perforation, tamponade, or sustained ventricular arrhythmias. RESULTS No patient had a treatment-emergent serious adverse events at day 30. The 1-year incidence of serious adverse events was 31.6% (95% CI, 12.6% to 56.6%) for MSCs, 31.6% (95% CI, 12.6%-56.6%) for BMCs, and 38.1% (95% CI, 18.1%-61.6%) for placebo. Over 1 year, the Minnesota Living With Heart Failure score improved with MSCs (-6.3; 95% CI, -15.0 to 2.4; repeated measures of variance, P=.02) and with BMCs (-8.2; 95% CI, -17.4 to 0.97; P=.005) but not with placebo (0.4; 95% CI, -9.45 to 10.25; P=.38). The 6-minute walk distance increased with MSCs only (repeated measures model, P = .03). Infarct size as a percentage of LV mass was reduced by MSCs (-18.9%; 95% CI, -30.4 to -7.4; within-group, P = .004) but not by BMCs (-7.0%; 95% CI, -15.7% to 1.7%; within-group, P = .11) or placebo (-5.2%; 95% CI, -16.8% to 6.5%; within-group, P = .36). Regional myocardial function as peak Eulerian circumferential strain at the site of injection improved with MSCs (-4.9; 95% CI, -13.3 to 3.5; within-group repeated measures, P = .03) but not BMCs (-2.1; 95% CI, -5.5 to 1.3; P = .21) or placebo (-0.03; 95% CI, -1.9 to 1.9; P = .14). Left ventricular chamber volume and ejection fraction did not change. CONCLUSIONS AND RELEVANCE Transendocardial stem cell injection with MSCs or BMCs appeared to be safe for patients with chronic ischemic cardiomyopathy and LV dysfunction. Although the sample size and multiple comparisons preclude a definitive statement about safety and clinical effect, these results provide the basis for larger studies to provide definitive evidence about safety and to assess efficacy of this new therapeutic approach. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00768066.
PMID: 24247587 [PubMed - as supplied by publisher]
Engraftment Efficacy of Human Hematopoietic Stem Cells Transplanted into NOD/SCID Mice Using Two Methods: Intra-Bone Marrow Transplantation of Hematopoietic Stem Cells and Intravenous Co-Transplantation with Mesenchymal Stem Cells.
Engraftment Efficacy of Human Hematopoietic Stem Cells Transplanted into NOD/SCID Mice Using Two Methods: Intra-Bone Marrow Transplantation of Hematopoietic Stem Cells and Intravenous Co-Transplantation with Mesenchymal Stem Cells.
Acta Haematol. 2013 Nov 12;131(3):179-182
Authors: Kim DS, Lee MW, Noh YH, Jang MC, Lee SH, Son MH, Jung HL, Yoo KH, Sung KW, Koo HH
PMID: 24247560 [PubMed - as supplied by publisher]
Loss of GADD34 induces early age-dependent deviation to the myeloid lineage.
Immunol Cell Biol. 2013 Nov 19;
Authors: Nishio N, Ito S, Isobe KI
Hematopoietic stem cells (HSCs) generate all known hematopoietic lineages and are capable of self-renewal. Upon aging, myeloid-biased HSCs are maintained, whereas lymphoid-biased HSCs are lost. GADD34 protein is expressed in myeloid-lineage cells and has been cloned from them. However, the function of GADD34 in the myeloid lineage has not yet been elucidated. Here, we show that early age-dependent deviation to the myeloid lineage occurs in GADD34-deficient mice. Early increases of GR-1(int)CD11b(+) and GR-1(high)CD11b(+) neutrophils were observed in the spleen, bone marrow (BM) and blood of GADD34-deficient mice. We found that BM Lin(-) c-Kit(+) Sca1(+) and Lin(-) c-Kit(+) Sca1(-)cells expressed GADD34 protein without stimulation and increased GADD34 expression following intravenous injection of Staphylococcus aureus (S.aureus). These cell populations were high in GADD34-deficient BM and were increased by the injection of S. aureus. Because of the increase in granulocyte colony-stimulating factor (G-CSF) induced by S. aureus injection, we examined the signaling pathway from the G-CSF receptor (G-CSFR). We found that phosphorylation of signal transducer and activator of transcription factor 3 was highly increased in GADD34-deficient Lin(-) BM cells by the stimulation of G-CSF. These results indicate that GADD34 binds to Lyn and inhibit G-CSFR signaling. We show here that GADD34 works to inhibit the proliferation and differentiation of HSCs or myeloid precursor cells and maintains homeostatic differentiation of neutrophil-lineage cells to avoid early immunological senescence.Immunology and Cell Biology advance online publication, 19 November 2013; doi:10.1038/icb.2013.78.
PMID: 24247289 [PubMed - as supplied by publisher]
Casticin suppresses self-renewal and invasion of lung cancer stem-like cells from A549 cells through down-regulation of pAkt.
Acta Biochim Biophys Sin (Shanghai). 2013 Nov 17;
Authors: Liu F, Cao X, Liu Z, Guo H, Ren K, Quan M, Zhou Y, Xiang H, Cao J
A subpopulation of cancer stem cells is recognized as the cause of tumorigenesis and spreading. To investigate the effects of casticin (5,3'-dihydroxy-3,6,7,4'-tetramethoxyflavone), derived from Fructus Viticis Simplicifoliae, on lung cancer stem cells, we isolated and identified a subpopulation of lung cancer stem-like cells (LCSLCs) from non-small-cell lung carcinoma A549 cells with the features including self-renewal capacity and high invasiveness in vitro, elevated tumorigenic activity in vivo, and high expression of stemness markers CD133, CD44, and aldehyde dehydrogenase 1 (ALDH1), using serum-free suspension sphere-forming culture method. We then found that casticin could suppress the proliferation of LCSLCs in a concentration-dependent manner with an IC50 value of 0.4 μmol/L, being much stronger than that in parental A549 cells. In addition, casticin could suppress the self-renewal and invasion of LCSLCs concomitant with decreased CD133, CD44, and ALDH1 protein expression and reduced MMP-9 activity. Further experiments showed that casticin suppressed self-renewal and invasion at least partly through down-regulation of Akt phosphorylation. In conclusion, casticin suppressed the characteristics of LCSLCs, suggesting that casticin may be a candidate compound for curing lung cancer via eliminating cancer stem cells.
PMID: 24247269 [PubMed - as supplied by publisher]
Lapatinib inhibits stem/progenitor proliferation in preclinical in vitro models of ductal carcinoma in situ (DCIS).
Cell Cycle. 2013 Feb 1;13(3)
Authors: Farnie G, Johnson RL, Williams K, Clarke RB, Bundred NJ
Breast-conserving surgery for ductal carcinoma in situ (DCIS) is often combined with irradiation, reducing recurrence rates to 20% within 10 years; however, there is no change in overall survival. Evidence in the invasive breast indicates that breast cancer stem cells (CSCs) are radiotherapy-resistant and are capable of re-initiating a tumor recurrence; hence, targeting CSCs in high risk DCIS patient may improve survival. HER2 is overexpressed in 20% of DCIS and is known to be highly active in breast CSCs; we therefore investigated the effect of Lapatinib on DCIS CSC activity using 2 in vitro culture systems. Two DCIS cell lines DCIS.com (HER2 normal) and SUM225 (HER2 overexpressed) as well as DCIS cells from patient samples (n = 18) were cultured as mammospheres to assess CSC activity and in differentiated 3D-matrigel culture to determine effects within the non-CSCs. Mammosphere formation was reduced regardless of HER2 status, although this was more marked within the HER2-positive samples. When grown as differentiated DCIS acini in 3D-matrigel culture, Lapatinib only reduced acini size in the HER2-positive samples via decreased proliferation. Further investigation revealed lapatinib did not reduce self-renewal activity in the CSC population, but their proliferation was decreased regardless of HER2 status. In conclusion we show Lapatinib can reduce DCIS CSC activity, suggesting that the use of Lapatinib in high-risk DCIS patients has the potential to reduce recurrence and the progression of DCIS to invasive disease.
PMID: 24247151 [PubMed - as supplied by publisher]
Intestinal stem cells.
Dig Dis. 2013;31(3-4):293-8
Authors: Stange DE
The intestine has become a prime model system to study stem cell biology. Intestinal stem cells can be identified based on the expression of a unique marker gene, namely Lgr5. A transgenic mouse model expressing green fluorescent protein in intestinal stem cells has allowed their visualization, isolation, molecular characterization and use in generating organoids: small mini-guts that contain all cell types of the intestine. Detailing the behavior of intestinal stem cells has also led to new insights concerning the mechanism of self-renewal versus differentiation. Genes and pathways directing daughter cells of stem cells towards the differentiated lineages of the intestine are getting better defined. Of all differentiated cells, Paneth cells play a distinguished role: they emerged from pure bystanders to the guardians of the stem cell. Taken together, a detailed molecular picture emerges that describes the mechanisms of intestinal homeostatic self-renewal and outlines new therapeutic avenues. © 2013 S. Karger AG, Basel.
PMID: 24246977 [PubMed - in process]
Hydrogen sulfide promotes proliferation and neuronal differentiation of neural stem cells and protects hypoxia-induced decrease in hippocampal neurogenesis.
Pharmacol Biochem Behav. 2013 Nov 15;
Authors: Liu D, Wang Z, Zhan J, Zhang Q, Wang J, Zhang Q, Xian X, Luan Q, Hao A
Accumulating evidence has suggested that hydrogen sulfide (H2S) acts as a novel neuro-modulator and neuroprotective agent; however, it remains to be investigated whether H2S has a direct effect on neural stem cells (NSCs). In the present study, we examined the effects of H2S donor, sodium hydrosulfide (NaHS) on mouse NSCs and hippocampal neurogenesis. We report here that NaHS promoted proliferation and neuronal differentiation of NSCs. Further analysis revealed that NaHS-induced proliferation was associated with phosphorylation of extracellular signal-regulated kinases (ERK) 1/2 and neuronal differentiation was linked to altered expression of differentiation-related genes. In addition, C57BL/6 mice (1day old) subjected to hypoxia were treated with NaHS to explore whether H2S would influence the neurogenesis of hippocampus. BrdU incorporation assay results showed that administration of NaHS could increase the number of proliferating cells in the dentate gyrus of hippocampus in the mice after hypoxia. Moreover, Morris water maze test showed that treatment with NaHS improved cognitive impairment after hypoxia in mice. These findings suggest that H2S may afford a novel therapeutic strategy to intervene in the progression of brain diseases.
PMID: 24246910 [PubMed - as supplied by publisher]
[In vitro study on expression of tumor stem cell biomarker and transdifferentiation towards endothelial cells of retinoblastoma cells under hypoxia condition].
Zhonghua Yan Ke Za Zhi. 2013 Aug;49(8):736-48
Authors: Zhang LN, Zhao GQ, Wang Q, Niu YJ, Xu Q, Yang WY
OBJECTIVE: To investigate the capability of RB cells that represent characteristics of tumor stem cell and trans-differentiate towards endothelial cells under hypoxia microenvironment, as well as their mechanism.
METHODS: Experimental research. RB cell line Y79 was cultured in hypoxia environment with or without rapamycin treatment. Morphological changes, expression of neuron specipic enolase (NES) and ATP binding cassette transporters G2 (ABCG2), and expression of HIF-1α protein and mRNA were detected. After been induced toward endothelial cells, expression of CD31 and vWF, up-taking of Dil-acLDL, vasculogenic mimicry (VM) formation in 3D culture and expression of HIF-1α,EphA2 and PI3K were detected. The ANOVA test was performed to compare the differences among groups, and SNK-q test was performed to further comparison.
RESULTS: Y79 cells in normal oxygen group were single or agminated suspending cells. In hypoxia group, part of Y79 cells became adherent. No adherent cells were observed in rapamycin fore-treated group. Positive rates of NES and ABCG2 had significant difference among these three groups (FNES = 698.45, FABCG2 = 864.48, all P < 0.01). Compared with normal group [(98.2 ± 2.5)%, (2.1 ± 2.1)%],NES positive rate [(35.1 ± 3.4)%] was significantly reduced and ABCG2 positive rate [(67.4 ± 3.6)%] was significantly enhanced in hypoxia group (q = 46.11, 50.89; both P < 0.01), no significant changes were observed in rapamycin fore-treated group(P > 0.05). Expressions of HIF-1α protein and mRNA showed significant difference among these three groups (Fprotein = 314.85, FmRNA = 132.01, all P < 0.01). Compared with normal oxygen group (0.165 ± 0.056,0.927 ± 0.715) , HIF-1α protein (1.094 ± 0.077) and mRNA (6.408 ± 0.686) were significantly increased in hypoxia group(q = 31.81, 18.40; both P < 0.01), HIF-1α mRNA (7.219 ± 0.591) was significantly increased but no increased protein expression (0.218 ± 0.061) was observed in rapamycin fore-treated group. After transdifferentiating induction,Y79 cell in hypoxia group expressed CD31 and vWF, acquired the abilities of acLDL up-taking and VM formation. Compared with normal group(0.327 ± 0.108, 0.194 ± 0.033, 0.402 ± 0.068), expression of HIF-1α,EphA2 and PI3K protein (1.440 ± 0.089,0.377 ± 0.056,0.762 ± 0.090) was significant increased in hypoxia group(q = 8.72-23.00, all P < 0.01).
CONCLUSIONS: Under hypoxic condition, part of RB cells can express tumor stem cell markers, transdifferentiate towards endothelial cells and acquire part of endothelial cell function and VM formation capability. HIF-1α through EphA2/PI3K pathway may play an important role in VM formation.
PMID: 24246814 [PubMed - in process]
Role of interferon-inducible protein 202 (p202) in the regulation of adipogenesis in mouse adipose-derived stem cells.
Mol Cell Endocrinol. 2013 Nov 15;
Authors: Li H, Liu F, Guo H, Zhu Z, Jiao Y
The interferon-inducible protein 202 (p202) has emerged as a key regulator of cell proliferation and differentiation. To explore the role of p202 in adipocyte differentiation, p202 mRNA and protein levels in differentiating mouse adipose-derived stem cells (mASCs) were examined, and were found to continuously increase during mASC adipogenesis. The nuclear and cytoplasmic distribution of p202 in the differentiation process was also determined. In addition, suppression and overexpression of p202 impaired and enhanced the differentiation process, respectively. Further, results of co-immunoprecipitation and co-immunofluorescence showed the interaction and intracellular co-localization of p202 with C/EBPβ, C/EBPα, and PPARγ at intermediate and/or late differentiation stages. Knockdown of p202 interfered with the elevated expression of C/EBPβ, C/EBPα, and PPARγ. In conclusion, the temporal and spatial profiles of p202 and the observed manner in which p202 affected the expression of these transcription factors provided evidence that p202 plays a role during mASC adipogenesis.
PMID: 24246779 [PubMed - as supplied by publisher]
Stem cells in preclinical spine studies.
Spine J. 2013 Nov 15;
Authors: Werner BC, Li X, Shen FH
BACKGROUND CONTEXT: The recent identification and characterization of mesenchymal stem cells have introduced a shift in the research focus for future technologies in spinal surgery to achieve spinal fusion and treat degenerative disc disease. Current and past techniques use allograft to replace diseased tissue or rely on host responses to recruit necessary cellular progenitors. Adult stem cells display long-term proliferation, efficient self-renewal, and multipotent differentiation.
PURPOSE: This review will focus on two important applications of stem cells in spinal surgery: spine fusion and the management of degenerative disc disease.
STUDY DESIGN: Review of the literature.
METHODS: Relevant preclinical literature regarding stem cell sources, growth factors, scaffolds, and animal models for both osteogenesis and chondrogenesis will be reviewed, with an emphasis on those studies that focus on spine applications of these technologies.
RESULTS: In both osteogenesis and chondrogenesis, adult stem cells derived from bone marrow or adipose show promise in preclinical studies. Various growth factors and scaffolds have also been shown to enhance the properties and eventual clinical potential of these cells. Although its utility in clinical applications has yet to be proven, gene therapy has also been shown to hold promise in preclinical studies.
CONCLUSIONS: The future of spine surgery is constantly evolving, and the recent advancements in stem cell-based technologies for both spine fusion and the treatment of degenerative disc disease is promising and indicative that stem cells will undoubtedly play a major role clinically. It is likely that these stem cells, growth factors, and scaffolds will play a critical role in the future for replacing diseased tissue in disease processes such as degenerative disc disease and in enhancing host tissue to achieve more reliable spine fusion.
PMID: 24246748 [PubMed - as supplied by publisher]
Changes in the frequencies of human hematopoietic stem and progenitor cells with age and site.
Exp Hematol. 2013 Nov 15;
Authors: Farrell TL, McGuire TR, Bilek L, Brusnahan SK, Jackson JD, Lane JT, Garvin KL, O'Kane BJ, Berger AM, Tuljapurkar SR, Kessinger MA, Sharp JG
This study enumerated CD45hi/CD34+ and CD45hi/CD133+ human hematopoietic stem cells (HSC) and granulocyte-monocyte colony forming (GM-CFC) progenitor cells in blood and trochanteric and femoral bone marrow in 233 individuals. Stem cell frequencies were determined by multi-parameter flow cytometry employing an internal control to determine the intrinsic variance of the assays. Progenitor cell frequency was determined using a standard colony assay technique. The frequency of outliers from undetermined methodological causes was highest for blood but less than 5% for all values. The frequency of CD45hi/CD133+ cells correlated highly with the frequency of CD45hi/CD34+ cells in trochanteric and femoral bone marrow. The frequency of these HSC populations in trochanteric and femoral bone marrow rose significantly with age. In contrast, there was no significant trend of either of these cell populations with age in the blood. Trochanteric marrow GM-CFC progenitor cells showed no significant trends with age, but femoral marrow GM-CFC trended downward with age, potentially because of the reported conversion of red marrow at this site to fat with age. Hematopoietic stem and progenitor cells exhibited changes in frequencies with age that differed between blood and bone marrow. We previously reported that side population (SP) multipotential HSC, that include the precursors of CD45hi/CD133+ and CD45hi/CD34+, decline with age. Potentially the increases in stem cell frequencies in the intermediate compartment between SP and GM progenitor cells observed in this study represent a compensatory increase for the loss of more potent members of the HSC hierarchy.
PMID: 24246745 [PubMed - as supplied by publisher]
Induced neural stem cells: Methods of reprogramming and potential therapeutic applications.
Prog Neurobiol. 2013 Nov 15;
Authors: Ruggieri M, Riboldi G, Brajkovic S, Bucchia M, Bresolin N, Comi GP, Corti S
Developmental studies and experimental data have enabled us to assert that the terminal cell differentiation state is reversible, and that altering the balance of specific transcription factors could be a powerful strategy for inducing pluripotency. Due to the risks related to using induced pluripotent cells in clinical applications, biologists are now striving to develop methods to induce a committed differentiated cell type by direct conversion of another cell line. Several reprogramming factors have been discovered, and some cellular phenotypes have been obtained by novel transdifferentiation processes. It has been recently demonstrated that induced neural stem cells (iNSCs) can be obtained from rodent and human somatic cells, like fibroblasts, through the forced expression of defined transcription factors. To date, two different approaches have been successfully used to obtain iNSCs: a direct method and an indirect method that involves an intermediate destabilized state. The possibility to induce characterised iNSCs from human cells, e.g. fibroblasts, has opened new horizons for research in human disease modelling and cellular therapeutic applications in the neurological field. This review focuses on reported reprogramming techniques and innovative techniques that can be further explored in this area, as well as on the criteria for the phenotypic characterization of iNSCs and their use in developing novel therapeutic strategies for neurological diseases.
PMID: 24246715 [PubMed - as supplied by publisher]
Immunosuppression does not affect human bone marrow mesenchymal stromal cell efficacy after transplantation in traumatized mice brain.
Neuropharmacology. 2013 Nov 15;
Authors: Pischiutta F, D'Amico G, Dander E, Biondi A, Biagi E, Citerio G, De Simoni MG, Zanier ER
The need for immunosuppression after allo/xenogenic mesenchymal stromal cell (MSC) transplantation is debated. This study compared the long-term effects of human (h) bone marrow MSC transplant in immunocompetent or immunosuppressed traumatic brain injured (TBI) mice. C57Bl/6 male mice were subjected to TBI or sham surgery followed 24h later by an intracerebroventricular infusion of phosphate buffer saline (PBS, control) or hMSC (150,000/5μl). Immunocompetent and cyclosporin-A immunosuppressed (CsA) mice were analyzed for gene expression at 72h, functional deficits and histological analysis at five weeks. Gene expression analysis showed the effectiveness of immunosuppression (INFγ reduction in CsA treated groups), with no evidence of early rejection (no changes of MHCII and CD86 in all TBI groups) and selective induction of Treg (increase of Foxp3) only in the TBI hMSC group. Five weeks after TBI, hMSC had comparable efficacy, with functional recovery (on both sensorimotor and cognitive deficits) and structural protection (contusion volume, vessel rescue effect, gliotic scar reduction, induction of neurogenesis) in immunosuppressed and immunocompetent mice. Therefore, long-term hMSC efficacy in TBI is not dependent on immunosuppressive treatment. These findings could have important clinical implication since immunosuppression in acute TBI patients may increase their risk of infection and not be tolerated.
PMID: 24246661 [PubMed - as supplied by publisher]
Molecular mechanisms of anticancer action and cell selectivity of short α-helical peptides.
Biomaterials. 2013 Nov 15;
Authors: Chen C, Hu J, Zeng P, Pan F, Yaseen M, Xu H, Lu JR
Development of functional biomaterials and drugs with good biocompatibility towards host cells but with high potency against cancer cells is a challenging endeavor. By drawing upon the advantageous features of natural antimicrobial peptides and α-helical proteins, we have designed a new class of short α-helical peptides G(IIKK)nI-NH2 (n = 1-4) with different potency and high selectivity against cancer cells. We show that the peptides with n = 3 and 4 kill cancer cells effectively whilst remaining benign to the host cells at their working concentrations, through mechanistic processes similar to their bactericidal effects. The high cell selectivity could stem from their preferential binding to the outer cell membranes containing negative charges and high fluidity. In addition to rapid membrane-permeabilizing capacities, the peptides can also induce the programmed cell death of cancer cells via both mitochondrial pathway and death receptor pathway, without inducing non-specific immunogenic responses. Importantly, these peptides can also inhibit tumor growth in a mouse xenograft model without eliciting side effects. Whilst this study reveals the clinical potential of these peptides as potent drugs and for other medical and healthcare applications, it also points to the significance of fundamental material research in the future development of highly selective peptide functional materials.
PMID: 24246647 [PubMed - as supplied by publisher]
Sensitive in vivo cell detection using size-optimized superparamagnetic nanoparticles.
Biomaterials. 2013 Nov 15;
Authors: Trekker J, Leten C, Struys T, Lazenka VV, Argibay B, Micholt L, Lambrichts I, Van Roy W, Lagae L, Himmelreich U
Magnetic nanoparticle (MNP) enabled cell visualization with magnetic resonance imaging (MRI) is currently an intensively studied area of research. In the present study, we have synthesized polyethylene glycolated (PEG) MNPs and validated their suitability as MR cell labeling agents in in vitro and in vivo experiments. The labeling of therapeutic potent mesenchymal stem cells (MSCs) with small core and large core MNPs was evaluated. Both MNPs were, in combination with a transfection agent, stably internalized into the MSCs and didn't show an effect on cell metabolism. The labeled cells showed high contrast in MRI phantom studies. For quantification purposes, the MRI contrast generating properties of cells labeled with small core MNPs were compared with large core MNPs and with the commercial contrast agent Endorem. MSCs labeled with the large core MNPs showed the highest contrast generating properties in in vitro phantom studies and in in vivo intracranial stereotactic injection experiments, confirming the size-relaxivity relationship in biological systems. Finally, the distribution of MSCs pre-labeled with large core PEGylated MNPs was visualized non-invasively with MRI in a glioma model.
PMID: 24246643 [PubMed - as supplied by publisher]
Novel evidence for enhanced stem cell trafficking in antipsychotic-naïve subjects during their first psychotic episode.
J Psychiatr Res. 2013 Nov 5;
Authors: Kucharska-Mazur J, Tarnowski M, Dołęgowska B, Budkowska M, Pędziwiatr D, Jabłoński M, Pełka-Wysiecka J, Kazimierczak A, Ratajczak MZ, Samochowiec J
In this study, we tested the novel hypothesis that stem cells and those factors that modulate their trafficking may be biological markers for acute psychosis. Twenty-eight subjects during their first nonaffective psychotic episode were investigated before and after antipsychotic treatment and were compared with 35 healthy controls (CG); the psychotic group (PG) was divided into "schizophrenic" (SG) and "non-schizophrenic" (NG) subgroups. We examined the number of circulating Lin(-)/CD45(-)/CD34(+) and Lin(-)/CD45(-)/CD133(+) very small embryonic-like stem cells (VSELs), which express markers of the neural lineage, and also the plasma levels of factors that modulate their trafficking: the C3a, C5a, and C5b-9 activated complement cascade components, stromal-derived factor 1, and sphingosine-1-phosphate (S1P). We found that the mean numbers of Lin(-)/CD45(-)/CD34(+) VSELs and the plasma levels of S1P prior to treatment differ between the CG and PG and that these cells express markers of neural lineage. The number of Lin(-)/CD45(-)/CD133(+) VSELs in peripheral blood differed between the SG and NG prior to treatment. Using logistic regression analysis, we found that C3a and S1P are the best predictors of risk and are potential markers for the first psychotic episode. Furthermore, in the SG, the number of circulating Lin(-)/CD45(-)/CD34(+) VSELs and the S1P plasma level are the best predictors of risk and are proposed as novel markers for the first "schizophrenic" episode of psychosis.
PMID: 24246416 [PubMed - as supplied by publisher]
The high-affinity CXCR4 antagonist BKT140 is safe and induces a robust mobilization of human CD34+ cells in patients with multiple myeloma.
Clin Cancer Res. 2013 Nov 18;
Authors: Peled A, Abraham M, Avivi I, Rowe JM, Beider K, Wald H, Tiomkin L, Ribakovsky L, Ribak Y, Ramati Y, Aviel S, Galun E, Shaw HL, Eizenberg O, Hardan I, Shimoni A, Nagler A
PURPOSE: CXCR4 plays an important role in the retention of stem cells (SCs) within the bone marrow. BKT140 is a 14-residue bio stable synthetic peptide which binds CXCR4 with a greater affinity compared with plerixafor (4nM vs 84nM). Studies in mice demonstrated the efficient and superior mobilization and transplantation of SCs collected with GCSF-BKT140, compared with those obtained when using SCs obtained with each one of these mobilizing agent alone. These results have served as a platform for the present clinical phase I study.
EXPERIMENTAL DESIGN: Eighteen patients with multiple myeloma (MM) who were preparing for their first autologous stem cell transplantation (ASCT) were included. Patients received a standard MM mobilization regimen, consisting of 3-4 gr/m2 cyclophosphamide (Day 0), followed by G-CSF at 5 μg/kg/d starting on day 5 and administered between 8 and 10 PM until the end of stem cell collection. A single injection of BKT140 (0.006, 0.03, 0.1, 0.3 and 0.9 mg/kg) was administered subcutaneously (SC) on day 10 in the early morning, followed by G-CSF 12 hr later.
RESULTS: BKT140 was well tolerated at all concentrations, and none of the patients developed grade III-IV toxicity. A single administration of BKT140 at the highest dose, 0.9 mg/kg, resulted in a robust mobilization and collection of CD34+ cells (20.6± 6.9x106/kg), which were obtained through a single apheresis. All transplanted patients received ~5.3x106 CD34+ cells/kg, which rapidly engrafted (n=17). The median time to neutrophil and platelet recovery was 12 and 14 days, respectively, at the highest dose (0.9 mg/kg).
PMID: 24246358 [PubMed - as supplied by publisher]
The Lgr5 Transgene is Expressed Specifically in Glycinergic Amacrine Cells in the Mouse Retina.
Exp Eye Res. 2013 Nov 15;
Authors: Sukhdeo K, Koch CE, Miller TE, Zhou H, Rivera M, Yan K, Cepko CL, Lathia JD, Rich JN
Retinal amacrine cells are a diverse set of interneurons within the inner nuclear layer. The canonical Wnt pathway is highly active within mature amacrine cells, but its role remains unclear. Leucine-rich repeat containing G-protein receptor 5 (Lgr5) is a newly identified component of the Wnt receptor complex that potentiates beta-catenin signaling. In multiple epithelial organs Lgr5 marks adult tissue stem cells. We investigated the expression of this gene using Lgr5-eGFP-IRES-CreER transgenic reporter mice. In the eye, Lgr5 was exclusively expressed in glycinergic amacrine cells in adult mice. Amacrine cells are post-mitotic and represent the first neuronal and non-stem cell lineage to express Lgr5. We further interrogated the spatiotemporal labeling of individual amacrine cells with controlled fluorophore expression. This "fluorofilling" technique provides a tool to study amacrine morphology and dissect neural networks.
PMID: 24246263 [PubMed - as supplied by publisher]
Mesenchymal stromal cells for the treatment of critical limb ischemia: context and perspective.
Stem Cell Res Ther. 2013 Nov 18;4(6):140
Authors: Gremmels H, Fledderus JO, Teraa M, Verhaar MC
Cell therapy using mesenchymal stromal cells (MSCs) is a promising new avenue of treatment for critical limb ischemia (CLI). Preclinical studies have suggested that MSCs enhance neovascularization in ischemic limbs. In this commentary, we discuss a recent study by Gupta and colleagues, one of the first human trials using allogeneic MSCs for CLI, in relation to the current state of knowledge regarding cell therapy for CLI.
PMID: 24246031 [PubMed - as supplied by publisher]
Antiangiogenic Tocotrienol Derivatives from Garcinia amplexicaulis.
J Nat Prod. 2013 Nov 18;
Authors: Lavaud A, Richomme P, Litaudon M, Andriantsitohaina R, Guilet D
Phytochemical investigation of a dichloromethane extract from Garcinia amplexicaulis stem bark led to the isolation of four new tocotrienols (1-4); two known tocotrienols, two triterpenes, and a xanthone were also isolated. Their structures were mainly established using NMR and MS methods. The main compounds isolated, δ-amplexichromanol (1) and γ-amplexichromanol (2), were evaluated on VEGF-induced angiogenesis using a Matrigel assay. Compounds 1 and 2 inhibited in vitro angiogenesis of VEGF-induced human primary endothelial cells in the low nanomolar range. Their capacity to inhibit VEGF-induced proliferation of endothelial cells partially explained this activity, although δ-amplexichromanol (1) also prevented adhesion and migration processes.
PMID: 24245984 [PubMed - as supplied by publisher]
Therapeutic potential of placenta-derived stem cells for liver diseases: Current status and perspectives.
J Obstet Gynaecol Res. 2013 Nov 18;
Authors: Miki T, Grubbs B
Over the last decade, there has been a growing interest in the human placenta as a unique source of stem cells. The placenta is a fetal organ that is normally discarded following delivery. Therefore, it is readily available as a source of cells without the ethical concerns normally associated with embryonic stem cells. These cells also carry less risk for age- and environmental-related DNA damage. In addition to these practical advantages of placenta-derived cells, amniotic epithelial cells possess unique stem cell-like biological characteristics. In contrast to other parts of the placenta, cells from the amniotic epithelium are derived from pluripotent epiblasts and possess the ability to differentiate into all three germ layers. From a translational perspective, amnion-derived stem cells are very attractive candidates for clinical application. These cells are genetically stable and do not demonstrate tumorigenicity upon transplantation, and may be endowed with immunomodulatory and/or anti-inflammatory properties. These unique characteristics have made amniotic epithelial cells attractive for use as stem cell-based therapies for liver disease. Human and rodent amniotic epithelial cells have already demonstrated their therapeutic efficacy in multiple animal models. Although the detailed mechanism by which the transplanted cells generate a therapeutic effect is not yet totally understood, these dramatic results have generated significant interest for consideration of these amnion-derived stem cells for clinical applications. This review covers recent findings of the therapeutic potential of amnion-derived stem cells for liver diseases, and provides perspectives for future developments.
PMID: 24245961 [PubMed - as supplied by publisher]
Study for the improvement of umbilical cord blood sampling using a new trial apparatus.
J Obstet Gynaecol Res. 2013 Nov 18;
Authors: Masaoka N, Morooka M, Nakajima Y, Ogata H, Kodo H, Kato S
AIM: The aim of this study was to evaluate the usefulness of the trial umbilical cord blood sampling bag for unrelated cord blood transplantation.
MATERIAL AND METHODS: Data were obtained from 100 vaginal deliveries. In 50 cases, umbilical cord blood (UCB) was taken with the traditional Kawasumi type UCB sampling bag. In another 50 cases, UCB were taken with trial UCB sampling bag offered by NIPRO Co. We compared the sampling volume between the two groups. Furthermore, 10 cases in each group were matched by sampling volume; we examined the quality of UCB on the number and concentration of nucleated cells, mononuclear cells, CD34+ cells and colony-forming unit granulocyte macrophage and the numbers tested positive for bacteria.
RESULTS: Whereas there were no significant differences in gestational weeks at sampling, the ratio of primipara women to multipara women, maternal age, and neonatal weight between the two groups, the sampling UCB volumes with the trial sampling bag were significantly higher than those with traditional sampling bags (P < 0.05). In addition, this phenomenon was more significant in the latter part of the study period (P < 0.05). On the other hand, there were no significant differences in the quality of UCB between the two groups.
CONCLUSION: Once clinicians have become accustomed to the trial UBC sampling bag, this method might be a useful method for collecting UCB for unrelated cord blood transplantation.
PMID: 24245945 [PubMed - as supplied by publisher]
Reprogram or reboot: small molecule approaches for the production of induced pluripotent stem cells and direct cell reprogramming.
ACS Chem Biol. 2013 Nov 18;
Authors: Jung DW, Kim WH, Williams DR
Stem cell transplantation is a potential therapy for regenerative medicine, which aims to restore tissues damaged by trauma, aging and diseases. Since its conception in the late 1990s, chemical biology has provided powerful and diverse small molecule tools for modulating stem cell function. Stem cell transplantation is a potential therapy for regenerative medicine, which aims to restore tissues damaged by trauma, aging and diseases. Embryonic stem cells could be an ideal source for transplantation, but ethical concerns restrict their development for cell therapy. The seminal advance of induced pluripotent stem cell (iPSC) technology provided an attractive alternative to human embryonic stem cells. However, iPSCs are not yet considered an ideal stem cell source, due to limitations associated with the reprogramming process and their potential tumorigenic behavior. This is an area of research where chemical biology has made a significant contribution to facilitate the efficient production of high quality iPSCs and elucidate the biological mechanisms governing their phenotype. In this review, we summarize these advances and discuss the latest progress in developing small molecule modulators. Moreover, we also review a new trend in stem cell research, which is the direct reprogramming of readily accessible cell types into clinically useful cells, such as neurons and cardiac cells. This is a research area where chemical biology is making a pivotal contribution and illustrates the many advantages of using small molecules in stem cell research.
PMID: 24245936 [PubMed - as supplied by publisher]
The effect of TGF-β1 and BMP-4 on bone marrow-derived stem cell morphology on a novel bioabsorbable nanocomposite material.
Artif Cells Nanomed Biotechnol. 2013 Nov 19;
Authors: Lakhani HA, de Mel A, Seifalian AM
Context: Congenital heart disease is a leading cause of death in the first year, with an incidence of 1.5 million worldwide. It can be treated with bypass surgery, but due to the limited availability of autologous grafts, there has been research into developing a completely tissue-engineered vascular graft. Our group has developed a small diameter, biodegradable nanocomposite graft which is non-thrombogenic and biostable. Objectives: This study looks at the effects of the growth factors, TGF-β1 and BMP-4 on bone marrow-derived stem cell (BMSC) morphology on a POSS PCL scaffold. Materials and methods: BMSCs were seeded onto a new nanocomposite of POSS (polyhedral oligomeric silsesquioxane) and PCL (poly[caprolactone-urea]urethane) and TGF-β1 and BMP-4 were used to induce differentiation of the cells to smooth muscle cells. The distribution of the cells was examined using confocal and electron microscopies and the phenotype of the cells was assessed using immunohistochemistry. Results: It was found that growth factor induction led to a decrease in cell growth on POSS PCL as compared to that of the control surface, and confocal microscopic analysis showed less cytoskeleton reorganization of these cells. After immunohistochemistry analysis, the BMSCs showed no differentiation to smooth muscle cells. Discussion: Growth factor induction on the static scaffold discs led to a change in morphology, with less spreading of the cells, a lower proliferation rate and no differentiation into SMCs. These findings can be attributed to the POSS PCL being manufactured by a coagulation technique, resulting in a structure with low stiffness.
PMID: 24245787 [PubMed - as supplied by publisher]
Data and implication based comparison of two chronic myeloid leukemia models.
Math Biosci Eng. 2013 Oct-Dec;10(5-6):1501-18
Authors: Everett RA, Zhao Y, Flores KB, Kuang Y
Chronic myeloid leukemia, a disorder of hematopoietic stem cells, is currently treated using targeted molecular therapy with imatinib. We compare two models that describe the treatment of CML, a multi-scale model (Model 1) and a simple cell competition model (Model 2). Both models describe the competition of leukemic and normal cells, however Model 1 also describes the dynamics of BCR-ABL, the oncogene targeted by imatinib, at the sub-cellular level. Using clinical data, we analyze the differences in estimated parameters between the models and the capacity for each model to predict drug resistance. We found that while both models fit the data well, Model 1 is more biologically relevant. The estimated parameter ranges for Model 2 are unrealistic, whereas the parameter ranges for Model 1 are close to values found in literature. We also found that Model 1 predicts long-term drug resistance from patient data, which is exhibited by both an increase in the proportion of leukemic cells as well as an increase in BCR-ABL/ABL Model 2, however, is not able to predict resistance and accurately model the clinical data. These results suggest that including sub-cellular mechanisms in a mathematical model of CML can increase the accuracy of parameter estimation and may help to predict long-term drug resistance.
PMID: 24245631 [PubMed - in process]
A calibrated agent-based computer model of stochastic cell dynamics in normal human colon crypts useful for in silico experiments.
Theor Biol Med Model. 2013 Nov 18;10(1):66
Authors: Bravo R, Axelrod DE
BACKGROUND: Normal colon crypts consist of stem cells, proliferating cells, and differentiated cells. Abnormal rates of proliferation and differentiation can initiate colon cancer. We have measured the variation in the number of each of these cell types in multiple crypts in normal human biopsy specimens. This has provided the opportunity to produce a calibrated computational model that simulates cell dynamics in normal human crypts, and by changing model parameter values, to simulate the initiation and treatment of colon cancer.
RESULTS: An agent-based model of stochastic cell dynamics in human colon crypts was developed in the multi-platform open-source application NetLogo. It was assumed that each cell's probability of proliferation and probability of death is determined by its position in two gradients along the crypt axis, a divide gradient and in a die gradient. A cell's type is not intrinsic, but rather is determined by its position in the divide gradient. Cell types are dynamic, plastic, and inter-convertible. Parameter values were determined for the shape of each of the gradients, and for a cell's response to the gradients. This was done by parameter sweeps that indicated the values that reproduced the measured number and variation of each cell type, and produced quasi-stationary stochastic dynamics. The behavior of the model was verified by its ability to reproduce the experimentally observed monocolonal conversion by neutral drift, the formation of adenomas resulting from mutations either at the top or bottom of the crypt, and by the robust ability of crypts to recover from perturbation by cytotoxic agents. One use of the virtual crypt model was demonstrated by evaluating different cancer chemotherapy and radiation scheduling protocols.
CONCLUSIONS: A virtual crypt has been developed that simulates the quasi-stationary stochastic cell dynamics of normal human colon crypts. It is unique in that it has been calibrated with measurements of human biopsy specimens, and it can simulate the variation of cell types in addition to the average number of each cell type. The utility of the model was demonstrated with in silico experiments that evaluated cancer therapy protocols. The model is available for others to conduct additional experiments.
PMID: 24245614 [PubMed - as supplied by publisher]
Apoptosis in capillary endothelial cells in ageing skeletal muscle.
Aging Cell. 2013 Nov 19;
Authors: Wang H, Listrat A, Meunier B, Gueugneau M, Coudy-Gandilhon C, Combaret L, Taillandier D, Polge C, Attaix D, Lethias C, Lee K, Goh KL, Béchet D
The age-related loss of skeletal muscle mass and function (sarcopenia) is a consistent hallmark of ageing. Apoptosis plays an important role in muscle atrophy, and the intent of this study was to specify whether apoptosis is restricted to myofibre nuclei (myonuclei) or occurs in satellite cells or stromal cells of extracellular matrix (ECM). Sarcopenia in mouse gastrocnemius muscle was characterized by myofibre atrophy, oxidative type grouping, delocalization of myonuclei and ECM fibrosis. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) indicated a sharp rise in apoptosis during ageing. TUNEL coupled with immunostaining for dystrophin, paired box protein-7 (Pax7) or laminin-2α, respectively, was used to identify apoptosis in myonuclei, satellite cells and stromal cells. In adult muscle, apoptosis was not detected in myofibres, but was restricted to stromal cells. Moreover, the age-related rise in apoptotic nuclei was essentially due to stromal cells. Myofibre-associated apoptosis nevertheless occurred in old muscle, but represented < 20% of the total muscle apoptosis. Specifically, apoptosis in old muscle affected a small proportion (0.8%) of the myonuclei, but a large part (46%) of the Pax7(+) satellite cells. TUNEL coupled with CD31 immunostaining further attributed stromal apoptosis to capillary endothelial cells. Age-dependent rise in apoptotic capillary endothelial cells was concomitant with altered levels of key angiogenic regulators, perlecan and a perlecan domain V (endorepellin) proteolytic product. Collectively, our results indicate that sarcopenia is associated with apoptosis of satellite cells and impairment of capillary functions, which is likely to contribute to the decline in muscle mass and functionality during ageing.
PMID: 24245531 [PubMed - as supplied by publisher]
The effects of C60(C(COOH)2)2-FITC on proliferation and differentiation of human mesenchymal stem cells in vitro.
J Nanosci Nanotechnol. 2013 Oct;13(10):6517-21
Authors: Li J, Song Y, Liu X, Zhang M, He R, Chang Y, Jin J, Xing GM, Zhang J
As manufactured nanoparticles, fullerene nanoparticles were used as the model to research the manufactured nanoparticles entering into cells and hence have been rapidly developed for biomedical uses. Human mesenchymal stem cells (hMSCs) have become the most widely used seeding cells in tissue engineering because they are readily obtained without ethical problems and are multipotent with regard to adipogenic, chondrogenic, and osteogenic lineages. Because of their favorable biological and cellular activities, C60 carboxyl derivatives are among the most widely studied C60 derivatives. FITC labeled C60(C(COOH)2)2 nanoparticles were charactered by FTIR, ESI-MS, XPS and DLS. The effects of C60(C(COOH)2)2-FITC on proliferation and differentiation of human mesenchymal stem cells (hMSCs) in vitro were observed. The fullerene nanoparticles are quickly internalized by the cells and they had low toxicity to proliferation of hMSCs. The C60(C(COOH)2)2 nanoparticles could promote cell proliferation, enhance osteoclast differentiation of hMSCs.
PMID: 24245108 [PubMed - in process]
Advances in Single-cell Tracking of Mesenchymal Stem Cells (MSCs) During Musculoskeletal Regeneration.
Orthop J Harv Med Sch. 2012 Dec 1;14:22-28
Authors: Phillips JA, Mortensen LJ, Ruiz JP, Sridharan R, Kumar S, Torres M, Sharma P, Lin CP, Karp JM, Hauschka PV
PMID: 24244929 [PubMed - as supplied by publisher]
Tumor-targeting vaccination instructs graft-vs.-tumor immune responses.
Oncoimmunology. 2013 Oct 1;2(10):e25996
Authors: Manzo T, Michelini RH, Sturmheit T, Basso V, Bellone M, Mondino A
Anticancer vaccines hold the potential to promote tumor eradication by immune effector cells. We have recently found dendritic cell-based vaccines to instruct graft-vs.-tumor responses following allogeneic hematopoietic stem cell transplantation and donor lymphocyte infusion. Vaccination was essential to elicit the intratumoral expression of interferon γ, promote local inflammation, and stimulate therapeutic T-cell infiltration.
PMID: 24244899 [PubMed - as supplied by publisher]
Intranasal Delivery of Neural Stem Cells: A CNS-specific, Non-invasive Cell-based Therapy for Experimental Autoimmune Encephalomyelitis.
J Clin Cell Immunol. 2013 Jun 1;4(3)
Authors: Wu S, Li K, Yan Y, Gran B, Han Y, Zhou F, Guan YT, Rostami A, Zhang GX
The therapeutic potential of adult neural stem cells (aNSCs) has been shown in EAE, an animal model of MS, administered by either i.c.v. or i.v. injection. However, i.c.v. is an invasive approach, while the i.v. route of aNSCs is associated with a non-specific immune suppression in the periphery. Here we demonstrate that intranasal (i.n.) delivery of fluorescently labeled aNSCs resulted in their appearance in the olfactory bulb, cortex, hippocampus, striatum, brainstem, and spinal cord. These cells induce functional recovery from ongoing EAE similar to that achieved with i.v. injected aNSCs, with comparable anti-inflammatory and remeylination effects in CNS inflammatory foci. Importantly, unlike the peripheral immune suppression brought about by i.v. NSCs, intranasal delivery did not influence peripheral immune responses. We conclude that aNSCs can be reliably delivered to the CNS via the nasal route to induce functional recovery and confer immunomodulation and remyelination in EAE. Intranasal administration of NSCs provides a highly promising, noninvasive and CNS-specific alternative to current cell-based approaches in treating EAE.
PMID: 24244890 [PubMed - as supplied by publisher]
Single site-specific integration targeting coupled with embryonic stem cell differentiation provides a high-throughput alternative to in vivo enhancer analyses.
Biol Open. 2013;2(11):1229-38
Authors: Wilkinson AC, Goode DK, Cheng YH, Dickel DE, Foster S, Sendall T, Tijssen MR, Sanchez MJ, Pennacchio LA, Kirkpatrick AM, Göttgens B
Comprehensive analysis of cis-regulatory elements is key to understanding the dynamic gene regulatory networks that control embryonic development. While transgenic animals represent the gold standard assay, their generation is costly, entails significant animal usage, and in utero development complicates time-course studies. As an alternative, embryonic stem (ES) cells can readily be differentiated in a process that correlates well with developing embryos. Here, we describe a highly effective platform for enhancer assays using an Hsp68/Venus reporter cassette that targets to the Hprt locus in mouse ES cells. This platform combines the flexibility of Gateway® cloning, live cell trackability of a fluorescent reporter, low background and the advantages of single copy insertion into a defined genomic locus. We demonstrate the successful recapitulation of tissue-specific enhancer activity for two cardiac and two haematopoietic enhancers. In addition, we used this assay to dissect the functionality of the highly conserved Ets/Ets/Gata motif in the Scl+19 enhancer, which revealed that the Gata motif is not required for initiation of enhancer activity. We further confirmed that Gata2 is not required for endothelial activity of the Scl+19 enhancer using Gata2(-/-) Scl+19 transgenic embryos. We have therefore established a valuable toolbox to study gene regulatory networks with broad applicability.
PMID: 24244860 [PubMed]
A stem cell proliferation burst forms new layers of P63 expressing suprabasal cells during zebrafish postembryonic epidermal development.
Biol Open. 2013;2(11):1179-86
Authors: Guzman A, Ramos-Balderas JL, Carrillo-Rosas S, Maldonado E
Organ growth during development is a highly regulated process with both temporal and spatial constraints. Epidermal stratification is essential for skin growth and development. Although the zebrafish has been well studied, it is not known when and how epidermal stratification occurs. This is because beyond the first five days of development our knowledge is currently limited. We found that epidermal stratification in zebrafish begins when the larvae reach a standard length (SL) of 6 mm at approximately 25 days of age. Over the next four days (from a SL of 6 to 9 mm), epidermis thickness increases almost four-fold. This represents a sudden increase in organ size, since for the previous 20 days of development, the epidermis has been only two layers thick. This pattern is different from that observed in mammals that undergo continuous stratification from E14.5-E18.5. To study how stem cell proliferation gives rise to the new epidermal layers, we used a combination of markers: one for cell proliferation (proliferating cell nuclear-antigen PCNA) and one for epidermal stem cells (P63 transcription factor). We identified, throughout the stratification process, two different waves of cell division. Initially, the most basal epidermal cells divided and generated a subset of suprabasal cells (possibly transient-amplifying cells); within the next several days, the basal cells stopped dividing, and the suprabasal cells began proliferation, giving rise to most of the cell types in the new layers. This part of the process is similar to what has been recently found during epidermal stratification in mammals.
PMID: 24244854 [PubMed]
EDA-Containing Fibronectin Increases Proliferation of Embryonic Stem Cells.
PLoS One. 2013;8(11):e80681
Authors: Losino N, Waisman A, Solari C, Luzzani C, Espinosa DF, Sassone A, Muro AF, Miriuka S, Sevlever G, Barañao L, Guberman A
Embryonic stem cells (ESC) need a set of specific factors to be propagated. They can also grow in conditioned medium (CM) derived from a bovine granulosa cell line BGC (BGC-CM), a medium that not only preserves their main features but also increases ESC´s proliferation rate. The mitogenic properties of this medium were previously reported, ascribing this effect to an alternative spliced generated fibronectin isoform that contains the extra domain A (FN EDA(+)). Here, we investigated if the FN EDA(+) isoform increased proliferation of mouse and human ES cells. We analyzed cell proliferation using conditioned media produced by different mouse embryonic fibroblast (MEF) lines genetically engineered to express FN constitutively including or excluding the EDA domain (FN EDA(-)), and in media supplemented with recombinant peptides containing or not the EDA. We found that the presence of EDA in the medium increased mouse and human ESC's proliferation rate. Here we showed for the first time that this FN isoform enhances ESC's proliferation. These findings suggest a possible conserved behavior for regulation of ES cells proliferation by this FN isoform and could contribute to improve their culturing conditions both for research and cell therapy.
PMID: 24244705 [PubMed - in process]
Mesenchymal Stem Cell Transplantation Enhancement in Myocardial Infarction Rat Model under Ultrasound Combined with Nitric Oxide Microbubbles.
PLoS One. 2013;8(11):e80186
Authors: Tong J, Ding J, Shen X, Chen L, Bian Y, Ma G, Yao Y, Yang F
OBJECTIVE: This study evaluated the effects of ultrasound combined with the homemade nitric oxide (NO) micro-bubble destruction on the in vitro proliferation, apoptosis, and migration of mesenchymal stem cells (MSCs). Furthermore, we studied whether or not irradiation of the NO micro-bubble combined with bone-marrow derived MSC infusion had a better effect on treating myocardial infarction. The possible mechanism of MSC delivery into the infarcted myocardium was also investigated.
METHODS: The murine bone marrow-derived MSCs were isolated, cultured, irradiated, and combined with different concentrations of NO microbubbles. MTT proliferation assay, annexin V-FITC apoptosis detection, migration assay, and RT-PCR were performed 24 h after the irradiation. The NO micro-bubbles was a intravenously injected, followed by the infusion of MSCs, which were labeled by CM-Dil. Myocardium was harvested 48 h later and the distribution of MSCs was observed by laser scanning confocal microscope after frozen sectioning. Echocardiography, histological examination, RT-PCR, and western blotting were performed four weeks after the cell transplantation.
RESULTS: Ultrasound combined with 1:70 NO micro-bubbles had no significant impact on the proliferation or apoptosis of MSCs. Transwell chamber findings demonstrated that MSCs migrated more efficiently in group that underwent ultrasound combined with 1:70 NO micro-bubbles. The Real-time PCR results indicated that the expression of CXCR4 was much higher in the group undergoing ultrasound combined with 1:70 NO micro-bubbles. The normalized fluorescence intensity greatly increased in the group of US+NO micro-bubbles and the cardiac function was also markedly improved. Immunohistochemical staining showed that the capillary density was much greater in the group of US+NO micro-bubbles as compared to that of the other groups. RT-PCR and western blotting also revealed a higher SDF-1 and VEGF expression in the group of US+NO micro-bubbles.
CONCLUSIONS: NO micro-bubbles could be used in the cell transplantation, which efficiently promoted the MSC homing into the infarcted myocardium.
PMID: 24244646 [PubMed - in process]
Lin28B Is an Oncofetal Circulating Cancer Stem Cell-Like Marker Associated with Recurrence of Hepatocellular Carcinoma.
PLoS One. 2013;8(11):e80053
Authors: Cheng SW, Tsai HW, Lin YJ, Cheng PN, Chang YC, Yen CJ, Huang HP, Chuang YP, Chang TT, Lee CT, Chao A, Chou CY, Chan SH, Chow NH, Ho CL
By using an expressed sequence tag bioinformatic algorithm, we identified that Lin28 homolog B (Lin28B) may have an oncofetal expression pattern which may facilitate detecting cancer cells in adults. It is also reported to be a potential marker for cancer stem cells. Therefore, we sought to verify oncofetal-stemness characters of Lin28B and test its potential as a circulating cancer stem cell-like marker in adult HCC patients. Lin28B mRNA was examined in a panel of fetal tissue, adult tissue and tumors. Lin28B was over-expressed or knocked down in HepG2 cells to evaluate its potential as a stem cell-like marker. RT-qPCR for Lin28B was performed in the peripheral blood mononuclear cells from patients with HCC receiving surgery (n=96) and non-HCC controls (n=60) and analyzed its clinical significance. Lin28B showed an oncofetal expression pattern. Its overexpression could upregulate stemness markers (OCT4, Nanog and SOX2) and enhance tumorsphere formation in vitro. Lin28B knockdown had opposite effects. Circulating Lin28B was detected in peripheral blood mononuclear cells in 3 cases (5%) of non-HCC controls and 32 cases (33.3%) of HCC patients. In HCC patients, circulating Lin28B was associated with high tumor grade (P=0.046), large size (P=0.005), high AJCC stage (P=0.044) and BCLC stage (P=0.017). Circulating Lin28B was significantly associated with decreased recurrence-free survival (P<0.001). Circulating Lin28B separated early stage HCC into 2 recurrence-free survival curves (P=0.003). In multivariate analysis, circulating Lin28B was an independent variable associated with early recurrence (P=0.045) and recurrence in early stage HCC (P=0.006). In conclusion, the oncofetal gene Lin28B is a potential oncofetal cancer-stem-cell-like circulating tumor cell marker that correlates with HCC recurrence after hepatectomy. Circulating Lin28B could refine early AJCC stages. Our finding supports the possible use of a TNMC (C for circulating tumor cells) staging system in HCC.
PMID: 24244607 [PubMed - in process]
Mouse-induced pluripotent stem cells differentiate into odontoblast-like cells with induction of altered adhesive and migratory phenotype of integrin.
PLoS One. 2013;8(11):e80026
Authors: Ozeki N, Mogi M, Kawai R, Yamaguchi H, Hiyama T, Nakata K, Nakamura H
Methods for differentiating induced pluripotent stem (iPS) cells into odontoblasts generally require epithelial-mesenchymal interactions. Here, we sought to characterize the cells produced by a 'hanging drop' technique for differentiating mouse iPS cells into odontoblast-like cells that requires no such interaction. Cells were cultured by the hanging drop method on a collagen type-I (Col-I) scaffold (CS) combined with bone morphogenetic protein (BMP)-4 (CS/BMP-4) without an epithelial-mesenchymal interaction. We evaluated the expression of odontoblast-related mRNA and protein, and the proliferation rate of these cells using reverse-transcription polymerase chain reaction, immunofluorescence staining, and BrdU cell proliferation enzyme-linked immunosorbent assay, respectively. The differentiated cells strongly expressed the mRNA for dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (Dmp-1), which are markers of mature odontoblasts. Osteopontin and osteocalcin were not expressed in the differentiated cells, demonstrating that the differentiated iPS cells bore little resemblance to osteoblasts. Instead, they acquired odontoblast-specific properties, including the adoption of an odontoblastic phenotype, typified by high alkaline phosphatase (ALP) activity and calcification capacity. The cell-surface expression of proteins such as integrins α2, α6, αV and αVβ3 was rapidly up-regulated. Interestingly, antibodies and siRNAs against integrin α2 suppressed the expression of DSPP and Dmp-1, reduced the activity of ALP and blocked calcification, suggesting that integrin α2 in iPS cells mediates their differentiation into odontoblast-like cells. The adhesion of these cells to fibronectin and Col-I, and their migration on these substrata, was significantly increased following differentiation into odontoblast-like cells. Thus, we have demonstrated that integrin α2 is involved in the differentiation of mouse iPS cells into odontoblast-like cells using the hanging drop culture method, and that these cells have the appropriate physiological and functional characteristics to act as odontoblasts in tissue engineering and regenerative therapies for the treatment of dentin and/or dental pulp damage.
PMID: 24244598 [PubMed - in process]
Inhibition of the CXCL12/CXCR4-Axis as Preventive Therapy for Radiation-Induced Pulmonary Fibrosis.
PLoS One. 2013;8(11):e79768
Authors: Shu HK, Yoon Y, Hong S, Xu K, Gao H, Hao C, Torres-Gonzalez E, Nayra C, Rojas M, Shim H
BACKGROUND: A devastating late injury caused by radiation is pulmonary fibrosis. This risk may limit the volume of irradiation and compromise potentially curative therapy. Therefore, development of a therapy to prevent this toxicity can be of great benefit for this patient population. Activation of the chemokine receptor CXCR4 by its ligand stromal cell-derived factor 1 (SDF-1/CXCL12) may be important in the development of radiation-induced pulmonary fibrosis. Here, we tested whether MSX-122, a novel small molecule and partial CXCR4 antagonist, can block development of this fibrotic process.
METHODOLOGY/PRINCIPAL FINDINGS: The radiation-induced lung fibrosis model used was C57BL/6 mice irradiated to the entire thorax or right hemithorax to 20 Gy. Our parabiotic model involved joining a transgenic C57BL/6 mouse expressing GFP with a wild-type mouse that was subsequently irradiated to assess for migration of GFP+ bone marrow-derived progenitor cells to the irradiated lung. CXCL12 levels in the bronchoalveolar lavage fluid (BALF) and serum after irradiation were determined by ELISA. CXCR4 and CXCL12 mRNA in the irradiated lung was determined by RNase protection assay. Irradiated mice were treated daily with AMD3100, an established CXCR4 antagonist; MSX-122; and their corresponding vehicles to determine impact of drug treatment on fibrosis development. Fibrosis was assessed by serial CTs and histology. After irradiation, CXCL12 levels increased in BALF and serum with a corresponding rise in CXCR4 mRNA within irradiated lungs consistent with recruitment of a CXCR4+ cell population. Using our parabiotic model, we demonstrated recruitment of CXCR4+ bone marrow-derived mesenchymal stem cells, identified based on marker expression, to irradiated lungs. Finally, irradiated mice that received MSX-122 had significant reductions in development of pulmonary fibrosis while AMD3100 did not significantly suppress this fibrotic process.
CONCLUSIONS/SIGNIFICANCE: CXCR4 inhibition by drugs such as MSX-122 may alleviate potential radiation-induced lung injury, presenting future therapeutic opportunities for patients requiring chest irradiation.
PMID: 24244561 [PubMed - in process]
Rhizoctonia Bataticola Lectin (RBL) Induces Caspase-8-Mediated Apoptosis in Human T-Cell Leukemia Cell Lines but Not in Normal CD3 and CD34 Positive Cells.
PLoS One. 2013;8(11):e79311
Authors: Pujari R, Eligar SM, Kumar N, Barkeer S, Reddy V, Swamy BM, Inamdar SR, Shastry P
We have previously demonstrated immunostimulatory activity of a fungal lectin, Rhizoctonia bataticola lectin (RBL), towards normal human peripheral blood mononuclear cells. The present study aimed to explore the anticancer activities of RBL using human leukemic T-cell lines, Molt-4, Jurkat and HuT-78. RBL exhibited significant binding (>90%) to the cell membrane that was effectively inhibited by complex glycoproteins such as mucin (97% inhibition) and asialofetuin (94% inhibition) but not simple sugars such as N-acetyl-D-galactosamine, glucose and sucrose. RBL induced a dose and time dependent inhibition of proliferation and induced cytotoxicity in the cell lines. The percentage of apoptotic cells, as determined by hypodiploidy, was 33% and 42% in Molt-4 and Jurkat cells, respectively, compared to 3.11% and 2.92% in controls. This effect was associated with a concomitant decrease in the G0/G1 population. Though initiator caspase-8 and -9 were activated upon exposure to RBL, inhibition of caspase-8 but not caspase-9 rescued cells from RBL-induced apoptosis. Mechanistic studies revealed that RBL induced cleavage of Bid, loss of mitochondrial membrane potential and activation of caspase-3. The expression of the anti-apoptotic proteins Bcl-2 and Bcl-X was down regulated without altering the expression of pro-apoptotic proteins- Bad and Bax. In contrast to leukemic cells, RBL did not induce apoptosis in normal PBMC, isolated CD3+ve cells and undifferentiated CD34+ve hematopoietic stem and progenitor cells (HSPCs). The findings highlight the differential effects of RBL on transformed and normal hematopoietic cells and suggest that RBL may be explored for therapeutic applications in leukemia.
PMID: 24244478 [PubMed - in process]
Requirement of SLD5 for Early Embryogenesis.
PLoS One. 2013;8(11):e78961
Authors: Mohri T, Ueno M, Nagahama Y, Gong ZY, Asano M, Oshima H, Oshima M, Fujio Y, Takakura N
SLD5 forms a GINS complex with PSF1, PSF2 and PSF3, which is essential for the initiation of DNA replication in lower eukaryotes. Although these components are conserved in mammals, their biological function is unclear. We show here that targeted disruption of SLD5 in mice causes a defect in cell proliferation in the inner cell mass, resulting in embryonic lethality at the peri-implantation stage, indicating that SLD5 is essential for embryogenesis. Moreover, this phenotype of SLD5 mutant mice is quite similar compared with that of PSF1 mutant mice. We have previously reported that haploinsufficiency of PSF1 resulted in failure of acute proliferation of bone marrow hematopoietic stem cells (HSCs) during reconstitution of bone marrow ablated by 5-FU treatment. Since SLD5 was highly expressed in bone marrow, we investigated its involvement in bone marrow reconstitution after bone marrow ablation as observed in PSF1 heterozygous mutant mice. However, heterozygous deletion of the SLD5 gene was found not to significantly affect bone marrow reconstitution. On the other hand, abundant SLD5 expression was observed in human cancer cell lines and heterozygous deletion of the gene attenuated tumor progression in a murine model of spontaneous gastric cancer. These indicated that requirement and dependency of SLD5 for cell proliferation is different in different cell types.
PMID: 24244394 [PubMed - in process]
Normal Hematopoietic Stem Cells within the AML Bone Marrow Have a Distinct and Higher ALDH Activity Level than Co-Existing Leukemic Stem Cells.
PLoS One. 2013;8(11):e78897
Authors: Schuurhuis GJ, Meel MH, Wouters F, Min LA, Terwijn M, de Jonge NA, Kelder A, Snel AN, Zweegman S, Ossenkoppele GJ, Smit L
Persistence of leukemic stem cells (LSC) after chemotherapy is thought to be responsible for relapse and prevents the curative treatment of acute myeloid leukemia (AML) patients. LSC and normal hematopoietic stem cells (HSC) share many characteristics and co-exist in the bone marrow of AML patients. For the development of successful LSC-targeted therapy, enabling eradication of LSC while sparing HSC, the identification of differences between LSC and HSC residing within the AML bone marrow is crucial. For identification of these LSC targets, as well as for AML LSC characterization, discrimination between LSC and HSC within the AML bone marrow is imperative. Here we show that normal CD34+CD38- HSC present in AML bone marrow, identified by their lack of aberrant immunophenotypic and molecular marker expression and low scatter properties, are a distinct sub-population of cells with high ALDH activity (ALDH(bright)). The ALDH(bright) compartment contains, besides normal HSC, more differentiated, normal CD34+CD38+ progenitors. Furthermore, we show that in CD34-negative AML, containing solely normal CD34+ cells, LSC are CD34- and ALDH(low). In CD34-positive AML, LSC are also ALDH(low) but can be either CD34+ or CD34-. In conclusion, although malignant AML blasts have varying ALDH activity, a common feature of all AML cases is that LSC have lower ALDH activity than the CD34+CD38- HSC that co-exist with these LSC in the AML bone marrow. Our findings form the basis for combined functionally and immunophenotypically based identification and purification of LSC and HSC within the AML bone marrow, aiming at development of highly specific anti-LSC therapy.
PMID: 24244383 [PubMed - in process]
The Enhanced Metastatic Potential of Hepatocellular Carcinoma (HCC) Cells with Sorafenib Resistance.
PLoS One. 2013;8(11):e78675
Authors: Chow AK, Ng L, Lam CS, Wong SK, Wan TM, Cheng NS, Yau TC, Poon RT, Pang RW
Acquired resistance towards sorafenib treatment was found in HCC patients, which results in poor prognosis. To investigate the enhanced metastatic potential of sorafenib resistance cells, sorafenib-resistant (SorR) cell lines were established by long-term exposure of the HCC cells to the maximum tolerated dose of sorafenib. Cell proliferation assay and qPCR of ABC transporter genes (ABCC1-3) were first performed to confirm the resistance of cells. Migration and invasion assays, and immunoblotting analysis on the expression of epithelial to mesenchymal transition (EMT) regulatory proteins were performed to study the metastatic potential of SorR cells. The expression of CD44 and CD133 were studied by flow cytometry and the gene expressions of pluripotency factors were studied by qPCR to demonstrate the enrichment of cancer stem cells (CSCs) in SorR cells. Control (CTL) and SorR cells were also injected orthotopically to the livers of NOD-SCID mice to investigate the development of lung metastasis. Increased expressions of ABCC1-3 were found in SorR cells. Enhanced migratory and invasive abilities of SorR cells were observed. The changes in expression of EMT regulatory proteins demonstrated an activation of the EMT process in SorR cells. Enriched proportion of CD44(+) and CD44(+)CD133(+) cells were also observed in SorR cells. All (8/8) mice injected with SorR cells demonstrated lung metastasis whereas only 1/8 mouse injected with CTL cells showed lung metastasis. HCC cells with sorafenib resistance demonstrated a higher metastatic potential, which may be due to the activated EMT process. Enriched CSCs were also demonstrated in the sorafenib resistant cells. This study suggests that advanced HCC patients with acquired sorafenib resistance may have enhanced tumor growth or distant metastasis, which raises the concern of long-term sorafenib treatment in advanced HCC patients who have developed resistance of sorafenib.
PMID: 24244338 [PubMed - in process]
Transcriptional Basis for the Inhibition of Neural Stem Cell Proliferation and Migration by the TGFβ-Family Member GDF11.
PLoS One. 2013;8(11):e78478
Authors: Williams G, Zentar MP, Gajendra S, Sonego M, Doherty P, Lalli G
Signalling through EGF, FGF and endocannabinoid (eCB) receptors promotes adult neurogenesis, and this can be modelled in culture using the Cor-1 neural stem cell line. In the present study we show that Cor-1 cells express a TGFβ receptor complex composed of the ActRIIB/ALK5 subunits and that a natural ligand for this receptor complex, GDF11, activates the canonical Smad2/3 signalling cascade and significantly alters the expression of ∼4700 gene transcripts within a few hours of treatment. Many of the transcripts regulated by GDF11 are also regulated by the EGF, FGF and eCB receptors and by the MAPK pathway - however, in general in the opposite direction. This can be explained to some extent by the observation that GDF11 inhibits expression of, and signalling through, the EGF receptor. GDF11 regulates expression of numerous cell-cycle genes and suppresses Cor-1 cell proliferation; interestingly we found down-regulation of Cyclin D2 rather than p27kip1 to be a good molecular correlate of this. GDF11 also inhibited the expression of numerous genes linked to cytoskeletal regulation including Fascin and LIM and SH3 domain protein 1 (LASP1) and this was associated with an inhibition of Cor-1 cell migration in a scratch wound assay. These data demonstrate GDF11 to be a master regulator of neural stem cell transcription that can suppress cell proliferation and migration by regulating the expression of numerous genes involved in both these processes, and by suppressing transcriptional responses to factors that normally promote proliferation and/or migration.
PMID: 24244313 [PubMed - in process]
Dose dependent side effect of superparamagnetic iron oxide nanoparticle labeling on cell motility in two fetal stem cell populations.
PLoS One. 2013;8(11):e78435
Authors: Diana V, Bossolasco P, Moscatelli D, Silani V, Cova L
Multipotent stem cells (SCs) could substitute damaged cells and also rescue degeneration through the secretion of trophic factors able to activate the endogenous SC compartment. Therefore, fetal SCs, characterized by high proliferation rate and devoid of ethical concern, appear promising candidate, particularly for the treatment of neurodegenerative diseases. Super Paramagnetic Iron Oxide nanoparticles (SPIOn), routinely used for pre-clinical cell imaging and already approved for clinical practice, allow tracking of transplanted SCs and characterization of their fate within the host tissue, when combined with Magnetic Resonance Imaging (MRI). In this work we investigated how SPIOn could influence cell migration after internalization in two fetal SC populations: human amniotic fluid and chorial villi SCs were labeled with SPIOn and their motility was evaluated. We found that SPIOn loading significantly reduced SC movements without increasing production of Reactive Oxygen Species (ROS). Moreover, motility impairment was directly proportional to the amount of loaded SPIOn while a chemoattractant-induced recovery was obtained by increasing serum levels. Interestingly, the migration rate of SPIOn labeled cells was also significantly influenced by a degenerative surrounding. In conclusion, this work highlights how SPIOn labeling affects SC motility in vitro in a dose-dependent manner, shedding the light on an important parameter for the creation of clinical protocols. Establishment of an optimal SPIOn dose that enables both a good visualization of grafted cells by MRI and the physiological migration rate is a main step in order to maximize the effects of SC therapy in both animal models of neurodegeneration and clinical studies.
PMID: 24244310 [PubMed - in process]
Ectopically expressed variant form of sperm mitochondria-associated cysteine-rich protein augments tumorigenicity of the stem cell population of lung adenocarcinoma cells.
PLoS One. 2013;8(11):e69095
Authors: Takahashi A, Hirohashi Y, Torigoe T, Tamura Y, Tsukahara T, Kanaseki T, Kochin V, Saijo H, Kubo T, Nakatsugawa M, Asanuma H, Hasegawa T, Kondo T, Sato N
Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are defined as a small population of cancer cells that have self-renewal ability, differentiation ability and high tumor-initiating ability. CSCs/CICs are resistant to cancer therapies including chemotherapy and radiotherapy. Therefore, CSCs/CICs are thought to be responsible for cancer recurrence and distant metastasis after treatment. However, the molecular mechanisms of CSCs/CICs are still elusive. In this study, we isolated CSCs/CICs as side population (SP) cells from lung carcinoma, colon carcinoma and breast carcinoma cells and analyzed the molecular mechanisms of CSCs/CICs. cDNA micro-array screening and RT-PCR analysis revealed that sperm mitochondria-associated cysteine-rich protein (SMCP) is ectopically expressed in SP cells. 5'-Rapid amplification of cDNA end (RACE) analysis revealed that the SMCP transcript in SP cells was a variant form (termed vt2) which is composed from only one exon. SMCP vt2 was detected in only cancer cells, whereas the wild-type (vt1) form of SMCP was expressed in the testis. SMCP was shown to have a role in tumor initiation by SMCP overexpression and SMCP knockdown using siRNAs in lung cancer cells. Taken together, the initiation results indicate that an ectopically expressed variant form of SMCP has a role in tumor initiation of CSCs/CICs and that the variant form of SMCP might be a novel CSC/CIC marker and a potential and promising target of CSC/CIC-targeting therapy.
PMID: 24244262 [PubMed - in process]
Correction: Established Thymic Epithelial Progenitor/Stem Cell-Like Cell Lines Differentiate into Mature Thymic Epithelial Cells and Support T Cell Development.
PLoS One. 2013;8(11)
Authors: Chen P, Zhang J, Zhan Y, Su J, Du Y, Xu G, Shi Y, Siebenlist U, Zhang X
[This corrects the article on p. e75222 in vol. 8.].
PMID: 24244256 [PubMed - as supplied by publisher]
Oct4 is required ∼e7.5 for proliferation in the primitive streak.
PLoS Genet. 2013 Nov;9(11):e1003957
Authors: Deveale B, Brokhman I, Mohseni P, Babak T, Yoon C, Lin A, Onishi K, Tomilin A, Pevny L, Zandstra PW, Nagy A, van der Kooy D
Oct4 is a widely recognized pluripotency factor as it maintains Embryonic Stem (ES) cells in a pluripotent state, and, in vivo, prevents the inner cell mass (ICM) in murine embryos from differentiating into trophectoderm. However, its function in somatic tissue after this developmental stage is not well characterized. Using a tamoxifen-inducible Cre recombinase and floxed alleles of Oct4, we investigated the effect of depleting Oct4 in mouse embryos between the pre-streak and headfold stages, ∼E6.0-E8.0, when Oct4 is found in dynamic patterns throughout the embryonic compartment of the mouse egg cylinder. We found that depletion of Oct4 ∼E7.5 resulted in a severe phenotype, comprised of craniorachischisis, random heart tube orientation, failed turning, defective somitogenesis and posterior truncation. Unlike in ES cells, depletion of the pluripotency factors Sox2 and Oct4 after E7.0 does not phenocopy, suggesting that ∼E7.5 Oct4 is required within a network that is altered relative to the pluripotency network. Oct4 is not required in extraembryonic tissue for these processes, but is required to maintain cell viability in the embryo and normal proliferation within the primitive streak. Impaired expansion of the primitive streak occurs coincident with Oct4 depletion ∼E7.5 and precedes deficient convergent extension which contributes to several aspects of the phenotype.
PMID: 24244203 [PubMed - in process]
A Genetic Approach to the Recruitment of PRC2 at the HoxD Locus.
PLoS Genet. 2013 Nov;9(11):e1003951
Authors: Schorderet P, Lonfat N, Darbellay F, Tschopp P, Gitto S, Soshnikova N, Duboule D
Polycomb group (PcG) proteins are essential for the repression of key factors during early development. In Drosophila, the polycomb repressive complexes (PRC) associate with defined polycomb response DNA elements (PREs). In mammals, however, the mechanisms underlying polycomb recruitment at targeted loci are poorly understood. We have used an in vivo approach to identify DNA sequences of importance for the proper recruitment of polycomb proteins at the HoxD locus. We report that various genomic re-arrangements of the gene cluster do not strongly affect PRC2 recruitment and that relatively small polycomb interacting sequences appear necessary and sufficient to confer polycomb recognition and targeting to ectopic loci. In addition, a high GC content, while not sufficient to recruit PRC2, may help its local spreading. We discuss the importance of PRC2 recruitment over Hox gene clusters in embryonic stem cells, for their subsequent coordinated transcriptional activation during development.
PMID: 24244202 [PubMed - in process]
The Histone Variant His2Av is Required for Adult Stem Cell Maintenance in the Drosophila Testis.
PLoS Genet. 2013 Nov;9(11):e1003903
Authors: Morillo Prado JR, Srinivasan S, Fuller MT
Many tissues are sustained by adult stem cells, which replace lost cells by differentiation and maintain their own population through self-renewal. The mechanisms through which adult stem cells maintain their identity are thus important for tissue homeostasis and repair throughout life. Here, we show that a histone variant, His2Av, is required cell autonomously for maintenance of germline and cyst stem cells in the Drosophila testis. The ATP-dependent chromatin-remodeling factor Domino is also required in this tissue for adult stem cell maintenance possibly by regulating the incorporation of His2Av into chromatin. Interestingly, although expression of His2Av was ubiquitous, its function was dispensable for germline and cyst cell differentiation, suggesting a specific role for this non-canonical histone in maintaining the stem cell state in these lineages.
PMID: 24244183 [PubMed - in process]
Ash1l methylates lys36 of histone h3 independently of transcriptional elongation to counteract polycomb silencing.
PLoS Genet. 2013 Nov;9(11):e1003897
Authors: Miyazaki H, Higashimoto K, Yada Y, Endo TA, Sharif J, Komori T, Matsuda M, Koseki Y, Nakayama M, Soejima H, Handa H, Koseki H, Hirose S, Nishioka K
Molecular mechanisms for the establishment of transcriptional memory are poorly understood. 5,6-dichloro-1-D-ribofuranosyl-benzimidazole (DRB) is a P-TEFb kinase inhibitor that artificially induces the poised RNA polymerase II (RNAPII), thereby manifesting intermediate steps for the establishment of transcriptional activation. Here, using genetics and DRB, we show that mammalian Absent, small, or homeotic discs 1-like (Ash1l), a member of the trithorax group proteins, methylates Lys36 of histone H3 to promote the establishment of Hox gene expression by counteracting Polycomb silencing. Importantly, we found that Ash1l-dependent Lys36 di-, tri-methylation of histone H3 in a coding region and exclusion of Polycomb group proteins occur independently of transcriptional elongation in embryonic stem (ES) cells, although both were previously thought to be consequences of transcription. Genome-wide analyses of histone H3 Lys36 methylation under DRB treatment have suggested that binding of the retinoic acid receptor (RAR) to a certain genomic region promotes trimethylation in the RAR-associated gene independent of its ongoing transcription. Moreover, DRB treatment unveils a parallel response between Lys36 methylation of histone H3 and occupancy of either Tip60 or Mof in a region-dependent manner. We also found that Brg1 is another key player involved in the response. Our results uncover a novel regulatory cascade orchestrated by Ash1l with RAR and provide insights into mechanisms underlying the establishment of the transcriptional activation that counteracts Polycomb silencing.
PMID: 24244179 [PubMed - in process]
RNAi-Dependent and Independent Control of LINE1 Accumulation and Mobility in Mouse Embryonic Stem Cells.
PLoS Genet. 2013 Nov;9(11):e1003791
Authors: Ciaudo C, Jay F, Okamoto I, Chen CJ, Sarazin A, Servant N, Barillot E, Heard E, Voinnet O
In most mouse tissues, long-interspersed elements-1 (L1s) are silenced via methylation of their 5'-untranslated regions (5'-UTR). A gradual loss-of-methylation in pre-implantation embryos coincides with L1 retrotransposition in blastocysts, generating potentially harmful mutations. Here, we show that Dicer- and Ago2-dependent RNAi restricts L1 accumulation and retrotransposition in undifferentiated mouse embryonic stem cells (mESCs), derived from blastocysts. RNAi correlates with production of Dicer-dependent 22-nt small RNAs mapping to overlapping sense/antisense transcripts produced from the L1 5'-UTR. However, RNA-surveillance pathways simultaneously degrade these transcripts and, consequently, confound the anti-L1 RNAi response. In Dicer(-/-) mESC complementation experiments involving ectopic Dicer expression, L1 silencing was rescued in cells in which microRNAs remained strongly depleted. Furthermore, these cells proliferated and differentiated normally, unlike their non-complemented counterparts. These results shed new light on L1 biology, uncover defensive, in addition to regulatory roles for RNAi, and raise questions on the differentiation defects of Dicer(-/-) mESCs.
PMID: 24244175 [PubMed - in process]
Comparing algorithms that reconstruct cell lineage trees utilizing information on microsatellite mutations.
PLoS Comput Biol. 2013 Nov;9(11):e1003297
Authors: Chapal-Ilani N, Maruvka YE, Spiro A, Reizel Y, Adar R, Shlush LI, Shapiro E
Organism cells proliferate and die to build, maintain, renew and repair it. The cellular history of an organism up to any point in time can be captured by a cell lineage tree in which vertices represent all organism cells, past and present, and directed edges represent progeny relations among them. The root represents the fertilized egg, and the leaves represent extant and dead cells. Somatic mutations accumulated during cell division endow each organism cell with a genomic signature that is unique with a very high probability. Distances between such genomic signatures can be used to reconstruct an organism's cell lineage tree. Cell populations possess unique features that are absent or rare in organism populations (e.g., the presence of stem cells and a small number of generations since the zygote) and do not undergo sexual reproduction, hence the reconstruction of cell lineage trees calls for careful examination and adaptation of the standard tools of population genetics. Our lab developed a method for reconstructing cell lineage trees by examining only mutations in highly variable microsatellite loci (MS, also called short tandem repeats, STR). In this study we use experimental data on somatic mutations in MS of individual cells in human and mice in order to validate and quantify the utility of known lineage tree reconstruction algorithms in this context. We employed extensive measurements of somatic mutations in individual cells which were isolated from healthy and diseased tissues of mice and humans. The validation was done by analyzing the ability to infer known and clear biological scenarios. In general, we found that if the biological scenario is simple, almost all algorithms tested can infer it. Another somewhat surprising conclusion is that the best algorithm among those tested is Neighbor Joining where the distance measure used is normalized absolute distance. We include our full dataset in Tables S1, S2, S3, S4, S5 to enable further analysis of this data by others.
PMID: 24244121 [PubMed - in process]
Differential Clinical Benefits of 5-Fluorouracil-based Adjuvant Chemotherapy for Patients with Stage III Colorectal Cancer According to CD133 Expression Status.
Jpn J Clin Oncol. 2013 Nov 14;
Authors: Shikina A, Shinto E, Hashiguchi Y, Ueno H, Naito Y, Okamoto K, Kubo T, Fukazawa S, Yamamoto J, Hase K
OBJECTIVE: CD133 has been recently identified as a marker of putative cancer stem cells in colorectal tumors. The ability of cancer stem cells to resist chemotherapy was clinically highlighted; however, whether CD133 expression can predict chemoresistance remains controversial. The objective of the study was to determine the relationship between clinical benefits of adjuvant chemotherapy and CD133 expression status in colorectal cancer.
METHODS: We enrolled 234 patients with Stage III colorectal cancer who underwent curative resection. Among them, 149 received 5-fluorouracil-based adjuvant chemotherapy (chemotherapy group) and 85 did not (surgery-alone group). We immunohistochemically stained the specimens for CD133 on specimens evaluated the benefits of adjuvant chemotherapy according to CD133 expression using the Kaplan-Meier method and log-rank test.
RESULTS: A comparison of disease-free survival between both the groups revealed a significant 3-year disease-free survival benefit of adjuvant chemotherapy in CD133-negative (92.2% versus 74.5%; P = 0.004), but not in CD133-positive patients (46.8% versus 52.9%; P = 0.67). Multivariate analysis corroborated the benefits of adjuvant chemotherapy in CD133-negative (P = 0.003, hazard ratio = 0.26), but not in CD133-positive patients.
CONCLUSIONS: CD133-positive patients showed resistance to 5-FU-based chemotherapy, while CD133-negative patients experienced significant survival benefits from adjuvant chemotherapy not shared by CD133-positive patients.
PMID: 24244031 [PubMed - as supplied by publisher]
Correction: mesenchymal stem cells inhibit human th17 cell differentiation and function and induce a T regulatory cell phenotype.
J Immunol. 2013 Dec 1;191(11):5777
Authors: Ghannam S, Pène J, Moquet-Torcy G, Jorgensen C, Yssel H
PMID: 24244029 [PubMed - in process]
Differences in the Phenotype, Cytokine Gene Expression Profiles, and In Vivo Alloreactivity of T Cells Mobilized with Plerixafor Compared with G-CSF.
J Immunol. 2013 Nov 15;
Authors: Lundqvist A, Smith AL, Takahashi Y, Wong S, Bahceci E, Cook L, Ramos C, Tawab A, McCoy JP, Read EJ, Khuu HM, Bolan CD, Joo J, Geller N, Leitman SF, Calandra G, Dunbar C, Kurlander R, Childs RW
Plerixafor (Mozobil) is a CXCR4 antagonist that rapidly mobilizes CD34(+) cells into circulation. Recently, plerixafor has been used as a single agent to mobilize peripheral blood stem cells for allogeneic hematopoietic cell transplantation. Although G-CSF mobilization is known to alter the phenotype and cytokine polarization of transplanted T cells, the effects of plerixafor mobilization on T cells have not been well characterized. In this study, we show that alterations in the T cell phenotype and cytokine gene expression profiles characteristic of G-CSF mobilization do not occur after mobilization with plerixafor. Compared with nonmobilized T cells, plerixafor-mobilized T cells had similar phenotype, mixed lymphocyte reactivity, and Foxp3 gene expression levels in CD4(+) T cells, and did not undergo a change in expression levels of 84 genes associated with Th1/Th2/Th3 pathways. In contrast with plerixafor, G-CSF mobilization decreased CD62L expression on both CD4 and CD8(+) T cells and altered expression levels of 16 cytokine-associated genes in CD3(+) T cells. To assess the clinical relevance of these findings, we explored a murine model of graft-versus-host disease in which transplant recipients received plerixafor or G-CSF mobilized allograft from MHC-matched, minor histocompatibility-mismatched donors; recipients of plerixafor mobilized peripheral blood stem cells had a significantly higher incidence of skin graft-versus-host disease compared with mice receiving G-CSF mobilized transplants (100 versus 50%, respectively, p = 0.02). These preclinical data show plerixafor, in contrast with G-CSF, does not alter the phenotype and cytokine polarization of T cells, which raises the possibility that T cell-mediated immune sequelae of allogeneic transplantation in humans may differ when donor allografts are mobilized with plerixafor compared with G-CSF.
PMID: 24244025 [PubMed - as supplied by publisher]
Blood stem cell fate regulation by Delta-1 mediated rewiring of IL-6 paracrine signaling.
Blood. 2013 Nov 15;
Authors: Csaszar E, Wang W, Usenko T, Qiao W, Delaney C, Bernstein ID, Zandstra PW
Increasing evidence supports the importance of cell extrinsic regulation in stem cell fate control. Hematopoietic stem cells (HSC) are responsive to local signals from their niche and to systemic feedback from progenitors and mature cells. The Notch ligand Delta-1 (DL1), a key component of the stem cell niche, regulates human hematopoietic lineage development in a dose-dependent manner and has been used clinically for primitive progenitor expansion. How DL1 acts to regulate HSC fate, and whether these actions are related to its lineage skewing effects, is poorly understood. Herein we demonstrate that although DL1 activates STAT3 signaling similarly to the gp130-activating cytokine IL-6, it has opposite effects on myeloid cell production. Mechanistically, these different outcomes are attributable to a DL1-mediated reduction in membrane (m) bound IL-6R expression, converting progenitor cells from being directly IL-6 responsive, to requiring both IL-6 and the soluble (s) IL-6R for activation. Concomitant reduction of both mIL-6R (by DL1 supplementation) and sIL6R (using dynamically fed cultures) reduced myeloid cell production and led to enhanced outputs of human HSCs. This work describes a new mode of cytokine action wherein DL1 changes cytokine receptor distributions on hematopoietic cells, altering feedback networks and their impact on stem cell fate.
PMID: 24243972 [PubMed - as supplied by publisher]
Mortalin and DJ-1 coordinately regulate hematopoietic stem cell function through the control of oxidative stress.
Blood. 2013 Nov 15;
Authors: Tai-Nagara I, Matsuoka S, Ariga H, Suda T
Hematopoietic stem cells (HSCs) maintain stemness through various mechanisms that protect against stressful conditions. Heat shock proteins (HSPs) preserve cell homeostasis during stress responses through protein quality control, suggesting that HSPs may safeguard HSCs against numerous traumata. Here, we show that mortalin, a mitochondrial HSP, plays an essential role in maintaining HSC properties by regulating oxidative stress. Mortalin is primarily localized in hematopoietic stem and progenitor cell (HSPC) compartments. In this study, the inhibition of mortalin function caused abnormal reactive oxygen species (ROS) elevation in HSCs and reduced HSC numbers. Knockdown (KD) of mortalin in HSPCs impaired their ability to repopulate and form colonies. Moreover, mortalin-KD HSCs could not maintain quiescence and showed severe downregulation of cyclin-dependent kinase inhibitor- and antioxidant-related genes. Conversely, HSCs that overexpressed mortalin maintained a high reconstitution capacity and low ROS levels. Furthermore, DJ-1, one of the genes responsible for Parkinson's disease, directly bound to mortalin and acted as a negative ROS regulator. Using DJ-1 deficient mice, we demonstrated that mortalin and DJ-1 coordinately maintain normal ROS levels and HSC numbers. Collectively, these results indicate that the mortalin/DJ-1 complex guards against mitochondrial oxidative stress and is indispensable for the maintenance of HSCs.
PMID: 24243970 [PubMed - as supplied by publisher]
Chondrogenic differentiation of mesenchymal stem cells in a hydrogel system based on an enzymatically crosslinked tyramine derivative of hyaluronan.
J Biomed Mater Res A. 2013 Nov 6;
Authors: Dvořáková J, Kučera L, Kučera J, Svík K, Foglarová M, Muthný T, Pravda M, Němcová M, Velebný V, Kubala L
Hyaluronan-based tissue substitutes are promising materials in cartilage reconstruction surgery. Herein, the chondrogenesis of human mesenchymal stem cells (MSC) in a hydrogel based on a tyramine derivative of hyaluronan crosslinked by hydrogen peroxidase (HA-TA) was evaluated. Human MSC seeded in the scaffold were incubated in standard chondrogenic medium and medium enriched with bone morphogenetic protein-6 (BMP6). Cell viability, the gene expression of selected markers (collagen type II, aggrecan, SOX9, collagen type X, and osteopontin), and the histological characteristics were examined during three weeks of in vitro cultivation. The tissue reaction of both unseeded and MSC seeded HA-TA scaffolds were tested in vivo after subcutaneous application in rats for 12 weeks. The data showed that cells resisted the process of crosslinking and remained viable for the whole time while exhibiting changes in cell organization. Human MSC cultivated in HA-TA hydrogel expressed genes of both chondrogenic and osteogenic differentiation and the addition of BMP6 revealed a tendency to potentiate both processes. Histological analysis of HA-TA in vivo implants did not reveal a chronic inflammatory reaction. In both cases, in vivo HA-TA implants were continuously degraded and MSC-seeded hydrogels tended to form clusters similar to in vitro samples. In conclusion, MSC chondrogenic differentiation may proceed in a HA-TA scaffold that is biocompatible. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
PMID: 24243864 [PubMed - as supplied by publisher]