Epigenetics finely tunes gene expression at a functionallevel without modifying the DNA sequence, thereby contributing to the complexity of genomic regulation. Satellite cells(SCs) are adult muscle stem cells that are...Epigenetics finely tunes gene expression at a functionallevel without modifying the DNA sequence, thereby contributing to the complexity of genomic regulation. Satellite cells(SCs) are adult muscle stem cells that are important for skeletal post-natal muscle growth, homeostasis and repair. The understanding of the epigenome of SCs at different stages and of the multiple layers of the post-transcriptional regulation of gene expression is constantly expanding. Dynamic interactions between different epigenetic mechanisms regulate the appropriate timing of muscle-specific gene expression and influence the lineage fate of SCs. In this review, we report and discuss the recent literature about the epigenetic control of SCs during the myogenic process from activation to proliferation and from their commitment to a muscle cell fate to their differentiation and fusion to myotubes. We describe how the coordinated activities of the histone methyltransferase families Polycomb group(Pc G), which represses the expression of developmentally regulated genes, and Trithorax group, which antagonizes the repressive activity of the Pc G, regulate myogenesis by restricting gene expression in a time-dependent manner during each step of the process. We discuss how histone acetylation and deacetylation occurs in specific loci throughout SC differentiation to enable the time-dependent transcription of specific genes. Moreover, we describe the multiple roles of micro RNA, an additional epigenetic mechanism, in regulating gene expression in SCs, by repressing or enhancing gene transcription or translation during each step of myogenesis. The importance of these epigenetic pathways in modulating SC activation and differentiation renders them as promising targets for disease interventions. Understanding the most recent findings regarding the epigenetic mechanisms that regulate SC behavior is useful from the perspective of pharmacological manipulation for improving muscle regeneration and for promoting muscle homeostasis under pathological condi展开更多
AIM: To study regeneration of damaged human and murine muscle implants and the contribution of added xenogeneic mesenchymal stem cells(MSCs).METHODS: Minced human or mouse skeletal muscle tissues were implanted togeth...AIM: To study regeneration of damaged human and murine muscle implants and the contribution of added xenogeneic mesenchymal stem cells(MSCs).METHODS: Minced human or mouse skeletal muscle tissues were implanted together with human or mouse MSCs subcutaneously on the back of non-obese diabetic/severe combined immunodeficient mice. The muscle tissues(both human and murine) were minced with scalpels into small pieces(< 1 mm3) and aliquoted in portions of 200 mm3. These portions were either cryopreserved in 10% dimethylsulfoxide or freshly implanted. Syngeneic or xenogeneic MSCs were added to the minced muscles directly before implantation. Implants were collected at 7, 14, 30 or 45 d after transplantation and processed for(immuno)histological analysis. The progression of muscle regeneration was assessed using a standard histological staining(hematoxylin-phloxinsaffron). Antibodies recognizing Pax7 and von Willebrand factor were used to detect the presence of satellite cells and blood vessels, respectively. To enable detection of the bone marrow-derived MSCs or their derivatives we used MSCs previously transduced with lentiviral vectors expressing a cytoplasmic LacZ gene. X-gal staining of the fixed tissues was used to detect β-galactosidase-positive cells and myofibers.RESULTS: Myoregeneration in implants of fresh murine muscle was evident as early as day 7, and progressed with time to occupy 50% to 70% of the implants. Regeneration of fresh human muscle was slower. These observations of fresh muscle implants were in contrast to the regeneration of cryopreserved murine muscle that proceeded similarly to that of fresh tissue except for day 45(P < 0.05). Cryopreserved human muscle showed minimal regeneration, suggesting that the freezing procedure was detrimental to human satellite cells. In fresh and cryopreserved mouse muscle supplemented with LacZ-tagged mouse MSCs, β-galactosidase-positive myofibers were identified early after grafting at the wellvascularized periphery of the implants. The contribution of human 展开更多
Background Recent studies indicate that bone marrow-derived cells may significantly contribute to atherosclerosis, post-angioplasty restenosis and transplantation-associated vasculopathy. The responsible bone marrow ...Background Recent studies indicate that bone marrow-derived cells may significantly contribute to atherosclerosis, post-angioplasty restenosis and transplantation-associated vasculopathy. The responsible bone marrow （BM） cells and mechanisms regulating the mobilization of these cells are currently unclear. The purpose of this study was to investigate the expression of granulocyte colony-stimulating factor （G-CSF） on injured arteries and its effects on mesenchymal stem cells （MSCs） differentiation into vascular smooth muscle cells （VSMCs） in the process of vascular remodeling. Methods Balloon-mediated vascular injury was established in female rats （n=100） which received radioprotective whole female BM cells by tail vein injection and male MSCs through a tibial BM injection after lethal irradiation. The injured and contralateral carotid arteries were harvested at 3, 7, 14 and 28 days after treatment. Results Morphometric analysis indicated that intima to media area-ratio （I/M ratio） significantly increased at 28 days, 0.899＋0.057 （P 〈0.01）, compared with uninjured arteries. Combining fluorescence in situ hybridization （FISH） and immunohistochemical analysis showed that a significant number of the neointimal cells derived from MSCs, （45.2~8.5）% at 28 days （P=0.01）, compared with （23.5~6.3）% at 14 days. G-CSF was induced in carotid arteries subject to balloon angioplasty （fold mRNA change=8.67＋0.63 at three days, relative G-CSF protein=0.657±0.011 at three days, P 〈0.01, respectively, compared with uninjured arteries）. G-CSF was chemotactic for MSCs but did not affect the differentiation of MSCs into smooth-muscle-like cells. Conclusion Increased expression of G-CSF by injured arteries plays an essential role in contribution to recruitment and homing of MSCs to the site of the arterial lesion.展开更多
Stress urinary incontinence(SUI), as an isolated symptom, is not a life threatening condition. However, the fear of unexpected urine leakage contributes to a significant decline in quality of life parameters for affli...Stress urinary incontinence(SUI), as an isolated symptom, is not a life threatening condition. However, the fear of unexpected urine leakage contributes to a significant decline in quality of life parameters for afflicted patients. Compared to other forms of incontinence, SUI cannot be easily treated with pharmacotherapy since it is inherently an anatomic problem. Treatment options include the use of bio-injectable materials to enhance closing pressures, and the placement of slings to bolster fascial support to the urethra. However, histologic findings of degeneration in the incontinent urethral sphincter invite the use of tissues engineering strategies to regenerate structures that aid in promoting continence. In this review, we will assess the role of stem cells in restoring multiple anatomic and physiological aspects of the sphincter. In particular, mesenchymal stem cells and CD34+cells have shown great promise to differentiate into muscular and vascular components,respectively. Evidence supporting the use of cytokines and growth factors such as hypoxia-inducible factor1-alpha, vascular endothelial growth factor, basic fi-broblast growth factor, hepatocyte growth factor and insulin-like growth factor further enhance the viability and direction of differentiation. Bridging the benefits of stem cells and growth factors involves the use of synthetic scaffolds like poly(1,8-octanediol-co-citrate)(POC) thin films. POC scaffolds are synthetic, elastomeric polymers that serve as substrates for cell growth,and upon degradation, release growth factors to the microenvironment in a controlled, predictable fashion.The combination of cellular, cytokine and scaffold elements aims to address the pathologic deficits to urinary incontinence, with a goal to improve patient symptoms and overall quality of life.展开更多
Critical Limb Ischaemia (CLI) is defined as the presence of rest pain, ulcers and/or gangrene in a limb for over 2 weeks. Associated exercise intolerance is caused by muscle fibre atrophy, fibro- fatty infiltration, n...Critical Limb Ischaemia (CLI) is defined as the presence of rest pain, ulcers and/or gangrene in a limb for over 2 weeks. Associated exercise intolerance is caused by muscle fibre atrophy, fibro- fatty infiltration, nerve dysfunction, mitochondrial damage and myofibril disorder. We aimed to determine the behaviour of satellite cells, responsible for the repair and regeneration of damaged muscle, in repairing the damage caused to critically ischaemic adult human skeletal muscle. CD34, pax7 and MyoD are all markers of satellite cells at different stages of the cell cycle and allow for an assessment of their number and activity in ischaemia. Local ethical committee approval and informed consent was obtained. Samples of harvested gastrocnemius muscle of patients undergoing major perigenicular amputation for CLI (n = 10) were analysed and compared to a control group undergoing coronary artery bypass grafting (n = 10). Using immunohistochemistry, the expression of pax7, CD34 and MyoD was assessed in five sequential blinded randomly generated fields. Statistical testing of the data collected was made via the Mann Whitney U test. Protein electrophoresis was used to confirm overall protein expression of the satellite cell markers. There was a significant increase in the number of satellite cells observed in CLI muscle sections as demonstrated by the expression of pax7 (2.4×?fold p ?Haematopoietic Stem Cells?(HSCs) and satellite cells were also more abundant, with a 2×?fold increase observed (p < 0.0001) whilst those cells expressing both CD34 and pax7 and identified as quiescent satellite cells, were significantly greater in number in the CLI samples (2.9×?fold p < 0.0001), confirmed via immunohistochemistry and protein electrophoresis. There was a significant decrease in the expression of MyoD positive or activated satellite cells (p < 0.0001). This indicates an increase in the proliferation of the satellite cell population as a response to CLI but less active cells are observed.展开更多
【目的】目前,越来越多的研究证明环状RNA(circRNA)在牛肌肉发育过程中扮演着重要的角色,但其分子调控机理尚未完善。通过挖掘与牛肌肉发育相关的circRNA的作用机制,为进一步阐明其调控牛肌肉发育的分子机制奠定基础。【方法】以前期分...【目的】目前,越来越多的研究证明环状RNA(circRNA)在牛肌肉发育过程中扮演着重要的角色,但其分子调控机理尚未完善。通过挖掘与牛肌肉发育相关的circRNA的作用机制,为进一步阐明其调控牛肌肉发育的分子机制奠定基础。【方法】以前期分析的增殖期(GM)与成肌分化期(DM)黄牛肌肉干细胞(MuSCs)的RNA-seq测序结果为基础,筛选出显著差异表达的circRNA,circCEP85L。采集新鲜黄牛胎牛的心脏、肝脏、脾脏、肺脏、肾脏、肌肉、肠和胃的组织样本,分离培养黄牛肌肉干细胞并诱导成肌分化,收集黄牛体外培养的GM与DM细胞,分别提取RNA并反转录为cDNA。通过实时荧光定量PCR(quantitative real time PCR,qRT-PCR)检测circCEP85L在不同组织及不同细胞状态的表达规律。同时,设计特异性引物扩增circCEP85L全长,构建过表达载体p-circCEP85L,质粒转染MuSCs后收集过表达circCEP85L细胞样本。以过表达质粒pCD5-ciR细胞样本为对照,采用qRT-PCR、流式细胞术、Western Blot及免疫荧光等技术检测过表达circCEP85L对黄牛MuSCs增殖、凋亡及成肌分化的影响。【结果】PCR电泳结果证明circCEP85L环化位点真实存在。CircCEP85L在多种组织中表达,并在DM期的表达量显著高于GM期(P<0.001);为了进一步探究对circCEP85L黄牛MuSCs的影响。将过表达载体p-circCEP85L与对照载体pCD5-ciR转染体外培养的黄牛MuSCs,继续培养24 h之后,EdU结果表明过表达circCEP85L能显著降低EdU阳性细胞比例(P<0.001);流式周期检测结果表明,过表达circCEP85L增加了G0/G1期细胞比例,显著减少S期细胞比例(P<0.001);流式凋亡结果表明,过表达circCEP85L显著抑制MuSCs的凋亡率(P<0.05)。QRT-PCR及Western blot检测黄牛MuSCs增殖及凋亡相关基因的表达情况,结果表明过表达circCEP85L后显著降低了黄牛MuSCs增殖及凋亡相关基因的mRNA表达水平(P<0.001),凋亡蛋白BAX的表达量也显著降低(P<0.01)。此外,为了展开更多
Dedifferentiation, as one of the mechanisms rerouting cell fate, regresses cells from a differentiated status to a more primitive one. Due to its potential of amplifying the stem/progenitor cell pool and reproducing s...Dedifferentiation, as one of the mechanisms rerouting cell fate, regresses cells from a differentiated status to a more primitive one. Due to its potential of amplifying the stem/progenitor cell pool and reproducing sizable and desirable cellular elements, it has been attended in the field of regenerative medicine, which will hopefully provide novel therapeutic strategies for currently incurable diseases, such as varieties of central nervous system (CNS) diseases and injuries. In this article, we will first discuss naturally occurring and experimentally induced dedifferentiation, and then set forth principles in stem-cell based therapy in the neural field;beyond that, we will introduce two recent studies that show dedifferentiated stem cells contribute to neural regeneration. Moreover, we also present our recent research results of dedifferentiated muscle stem cells for neurogenic differentiation study in vitro. Further work will be conducted to elucidate the mechanism underlying the dedifferentiation process to facilitate the development of new strategies in regenerative medicine.展开更多
Androgen doping in power sports is undeniably rampant worldwide. There is strong evidence that androgen administration in men increases skeletal muscle mass, maximal voluntary strength and muscle power. However, we do...Androgen doping in power sports is undeniably rampant worldwide. There is strong evidence that androgen administration in men increases skeletal muscle mass, maximal voluntary strength and muscle power. However, we do not have good experimental evidence to support the presumption that androgen administration improves physical function or athletic performance. Androgens do not increase specific force or whole body endurance measures. The anabolic effects of testosterone on the skeletal muscle are mediated through androgen receptor signaling. Testosterone promotes myogenic differentiation of multipotent mesenchymal stem cells and inhibits their differentiation into the adipogenic lineage. Testosterone binding to androgen receptor induces a conformational change in androgen receptor protein, causing it to associate with beta-catenin and TCF-4 and activate downstream Wnt target genes thus promoting myogenic differentiation. The adverse effects of androgens among athletes and recreational bodybuilders are under reported and include acne, deleterious changes in the cardiovascular risk factors, including a marked decrease in plasma high-density lipoproteins （HDL） cholesterol level, suppression of spermatogenesis resulting in infertility, increase in liver enzymes, hepatic neoplasms, mood and behavioral disturbances, and long term suppression of the endogenous hypothalamic-pituitary-gonadal axis. Androgens are often used in combination with other drugs which may have serious adverse events of their own. In spite of effective methods for detecting androgen doping, the policies for screening of athletes are highly variable in different countries and organizations and even existing policies are not uniformly enforced.展开更多
Over the last years,the existence of different stem cells with myogenic potential has been widely investigated.Be-sides the classical skeletal muscle progenitors represented by satellite cells,numerous multipotent and...Over the last years,the existence of different stem cells with myogenic potential has been widely investigated.Be-sides the classical skeletal muscle progenitors represented by satellite cells,numerous multipotent and embryologi-cally unrelated progenitors with a potential role in muscle differentiation and repair have been identified.In order to conceive a therapeutic approach for degenerative muscle disorders,it is of primary importance to identify an ideal stem cell endowed with all the features for a possible use in vivo.Among all emerging populations,vessel-associated stem cells are a novel and promising class of multipotent progenitors of mesodermal origin and with high myogenic potential which seem to best fit all the requirements for a possible cell therapy.In vitro and in vivo studies have already tested the effectiveness and safety of vessel-associated stem cells in animal models.This leads to the concrete possibility in the future to start pilot human clinical trials,hopefully opening the way to a turn-ing point in the treatment of genetic and acquired muscle disorders.展开更多
OBJECTIVE： To identify global research trends of muscle-derived stem cells （MDSCs） using a bibliometric analysis of the Web of Science, Research Portfolio Online Reporting Tools of the National Institutes of Health...OBJECTIVE： To identify global research trends of muscle-derived stem cells （MDSCs） using a bibliometric analysis of the Web of Science, Research Portfolio Online Reporting Tools of the National Institutes of Health （NIH）, and the Clinical Trials registry database （ClinicalTrials.gov）. DATA RETRIEVAL： We performed a bibliometric analysis of data retrievals for MDSCs from 2002 to 2011 using the Web of Science, NIH, and ClinicalTrials.gov. SELECTION CRITERIA： Inclusion criteria： （1） Web of Science： （a） peer-reviewed articles on MDSCs that were published and indexed in the Web of Science. （b） Type of articles： original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material and news items. （c） Year of publication： 2002-2011. （d） Citation databases： Science Citation Index-Expanded （SCI-E）, 1899-present; Conference Proceedings Citation Index-Science （CPCI-S）, 1991-present; Book Citation Index-Science （BKCI-S）, 2005-present. （2） NIH： （a） Projects on MDSCs supported by the NIH. （b） Fiscal year： 1988-present. （3） ClinicalTrials.gov： All clinical trials relating to MDSCs were searched in this database. Exclusion criteria： （1） Web of Science： （a） Articles that required manual searching or telephone access. （b） We excluded documents that were not published in the public domain. （c） We excluded a number of corrected papers from the total number of articles. （d） We excluded articles from the following databases： Social Sciences Citation Index （SSCI）, 1898-present; Arts ＆ Humanities Citation Index （A＆HCI）, 1975-present; Conference Proceedings Citation Index - Social Science ＆ Humanities （CPCI-SSH）, 1991-present; Book Citation Index - Social Sciences ＆ Humanities （BKCI-SSH）, 2005-present; Current Chemical Reactions （CCR-EXPANDED）, 1985-present; Index Chemicus （IC）, 1993-present. （2） NIH： （a） We excluded publications related to MDSCs that展开更多
Bone marrow mesenchymal stem cells (MSCs) can differentiate into smooth muscle cells (SMCs) and have tremendous potential for cell therapy and tissue engineering. In this study, to understand the effects of TGF-β3 on...Bone marrow mesenchymal stem cells (MSCs) can differentiate into smooth muscle cells (SMCs) and have tremendous potential for cell therapy and tissue engineering. In this study, to understand the effects of TGF-β3 on rat bone marrow-derived MSCs and the underlying molecular mechanism of this differentiation process, we investigated that the changes of myocardin-related transcription factors (MRTFs) at the transcriptional level after rat MSCs were treated with TGF-β3. The results showed that TGF-β3 increased the expression of contractile genes, such as SM22, smooth muscle-myosin heavy chain (SM- MHC), SM-α-actin in MSCs. When TGF-β3 induced MSCs differentiation into SMCs, myocardin and MRTF-A were activated. The data indicated that TGF-β3 induced rat bone marrow-derived MSCs differentiation into SMCs by activating mypcardin and MRTF-A.展开更多
基金SA:Sapienza University 2012(#C26A125ENW)and PRIN 2012(#2012N8YJC3)NM:Sapienza University"Avvio alla ricerca"2014VM:EU Marie Curie"Muscle repair-Mdx",Italian Ministry of Instruction,University and Research FIRB project and Italian Ministry of Health"Ricerca finalizzata"grants
文摘Epigenetics finely tunes gene expression at a functionallevel without modifying the DNA sequence, thereby contributing to the complexity of genomic regulation. Satellite cells(SCs) are adult muscle stem cells that are important for skeletal post-natal muscle growth, homeostasis and repair. The understanding of the epigenome of SCs at different stages and of the multiple layers of the post-transcriptional regulation of gene expression is constantly expanding. Dynamic interactions between different epigenetic mechanisms regulate the appropriate timing of muscle-specific gene expression and influence the lineage fate of SCs. In this review, we report and discuss the recent literature about the epigenetic control of SCs during the myogenic process from activation to proliferation and from their commitment to a muscle cell fate to their differentiation and fusion to myotubes. We describe how the coordinated activities of the histone methyltransferase families Polycomb group(Pc G), which represses the expression of developmentally regulated genes, and Trithorax group, which antagonizes the repressive activity of the Pc G, regulate myogenesis by restricting gene expression in a time-dependent manner during each step of the process. We discuss how histone acetylation and deacetylation occurs in specific loci throughout SC differentiation to enable the time-dependent transcription of specific genes. Moreover, we describe the multiple roles of micro RNA, an additional epigenetic mechanism, in regulating gene expression in SCs, by repressing or enhancing gene transcription or translation during each step of myogenesis. The importance of these epigenetic pathways in modulating SC activation and differentiation renders them as promising targets for disease interventions. Understanding the most recent findings regarding the epigenetic mechanisms that regulate SC behavior is useful from the perspective of pharmacological manipulation for improving muscle regeneration and for promoting muscle homeostasis under pathological condi
基金Supported by A scholarship to AS de la Garza-Rodea from the Universidad Autonoma de Nuevo Leon,Monterrey,Mexico
文摘AIM: To study regeneration of damaged human and murine muscle implants and the contribution of added xenogeneic mesenchymal stem cells(MSCs).METHODS: Minced human or mouse skeletal muscle tissues were implanted together with human or mouse MSCs subcutaneously on the back of non-obese diabetic/severe combined immunodeficient mice. The muscle tissues(both human and murine) were minced with scalpels into small pieces(< 1 mm3) and aliquoted in portions of 200 mm3. These portions were either cryopreserved in 10% dimethylsulfoxide or freshly implanted. Syngeneic or xenogeneic MSCs were added to the minced muscles directly before implantation. Implants were collected at 7, 14, 30 or 45 d after transplantation and processed for(immuno)histological analysis. The progression of muscle regeneration was assessed using a standard histological staining(hematoxylin-phloxinsaffron). Antibodies recognizing Pax7 and von Willebrand factor were used to detect the presence of satellite cells and blood vessels, respectively. To enable detection of the bone marrow-derived MSCs or their derivatives we used MSCs previously transduced with lentiviral vectors expressing a cytoplasmic LacZ gene. X-gal staining of the fixed tissues was used to detect β-galactosidase-positive cells and myofibers.RESULTS: Myoregeneration in implants of fresh murine muscle was evident as early as day 7, and progressed with time to occupy 50% to 70% of the implants. Regeneration of fresh human muscle was slower. These observations of fresh muscle implants were in contrast to the regeneration of cryopreserved murine muscle that proceeded similarly to that of fresh tissue except for day 45(P < 0.05). Cryopreserved human muscle showed minimal regeneration, suggesting that the freezing procedure was detrimental to human satellite cells. In fresh and cryopreserved mouse muscle supplemented with LacZ-tagged mouse MSCs, β-galactosidase-positive myofibers were identified early after grafting at the wellvascularized periphery of the implants. The contribution of human
基金This study was supported by grants from the National Natural Science Foundation of China （No. 30770899 to NIE Ru-qiong）, the Natural Science Foundation of Guangdong Province （No. 8151008901000072 to NIE Ru-qiong）.
文摘Background Recent studies indicate that bone marrow-derived cells may significantly contribute to atherosclerosis, post-angioplasty restenosis and transplantation-associated vasculopathy. The responsible bone marrow （BM） cells and mechanisms regulating the mobilization of these cells are currently unclear. The purpose of this study was to investigate the expression of granulocyte colony-stimulating factor （G-CSF） on injured arteries and its effects on mesenchymal stem cells （MSCs） differentiation into vascular smooth muscle cells （VSMCs） in the process of vascular remodeling. Methods Balloon-mediated vascular injury was established in female rats （n=100） which received radioprotective whole female BM cells by tail vein injection and male MSCs through a tibial BM injection after lethal irradiation. The injured and contralateral carotid arteries were harvested at 3, 7, 14 and 28 days after treatment. Results Morphometric analysis indicated that intima to media area-ratio （I/M ratio） significantly increased at 28 days, 0.899＋0.057 （P 〈0.01）, compared with uninjured arteries. Combining fluorescence in situ hybridization （FISH） and immunohistochemical analysis showed that a significant number of the neointimal cells derived from MSCs, （45.2~8.5）% at 28 days （P=0.01）, compared with （23.5~6.3）% at 14 days. G-CSF was induced in carotid arteries subject to balloon angioplasty （fold mRNA change=8.67＋0.63 at three days, relative G-CSF protein=0.657±0.011 at three days, P 〈0.01, respectively, compared with uninjured arteries）. G-CSF was chemotactic for MSCs but did not affect the differentiation of MSCs into smooth-muscle-like cells. Conclusion Increased expression of G-CSF by injured arteries plays an essential role in contribution to recruitment and homing of MSCs to the site of the arterial lesion.
文摘Stress urinary incontinence(SUI), as an isolated symptom, is not a life threatening condition. However, the fear of unexpected urine leakage contributes to a significant decline in quality of life parameters for afflicted patients. Compared to other forms of incontinence, SUI cannot be easily treated with pharmacotherapy since it is inherently an anatomic problem. Treatment options include the use of bio-injectable materials to enhance closing pressures, and the placement of slings to bolster fascial support to the urethra. However, histologic findings of degeneration in the incontinent urethral sphincter invite the use of tissues engineering strategies to regenerate structures that aid in promoting continence. In this review, we will assess the role of stem cells in restoring multiple anatomic and physiological aspects of the sphincter. In particular, mesenchymal stem cells and CD34+cells have shown great promise to differentiate into muscular and vascular components,respectively. Evidence supporting the use of cytokines and growth factors such as hypoxia-inducible factor1-alpha, vascular endothelial growth factor, basic fi-broblast growth factor, hepatocyte growth factor and insulin-like growth factor further enhance the viability and direction of differentiation. Bridging the benefits of stem cells and growth factors involves the use of synthetic scaffolds like poly(1,8-octanediol-co-citrate)(POC) thin films. POC scaffolds are synthetic, elastomeric polymers that serve as substrates for cell growth,and upon degradation, release growth factors to the microenvironment in a controlled, predictable fashion.The combination of cellular, cytokine and scaffold elements aims to address the pathologic deficits to urinary incontinence, with a goal to improve patient symptoms and overall quality of life.
文摘Critical Limb Ischaemia (CLI) is defined as the presence of rest pain, ulcers and/or gangrene in a limb for over 2 weeks. Associated exercise intolerance is caused by muscle fibre atrophy, fibro- fatty infiltration, nerve dysfunction, mitochondrial damage and myofibril disorder. We aimed to determine the behaviour of satellite cells, responsible for the repair and regeneration of damaged muscle, in repairing the damage caused to critically ischaemic adult human skeletal muscle. CD34, pax7 and MyoD are all markers of satellite cells at different stages of the cell cycle and allow for an assessment of their number and activity in ischaemia. Local ethical committee approval and informed consent was obtained. Samples of harvested gastrocnemius muscle of patients undergoing major perigenicular amputation for CLI (n = 10) were analysed and compared to a control group undergoing coronary artery bypass grafting (n = 10). Using immunohistochemistry, the expression of pax7, CD34 and MyoD was assessed in five sequential blinded randomly generated fields. Statistical testing of the data collected was made via the Mann Whitney U test. Protein electrophoresis was used to confirm overall protein expression of the satellite cell markers. There was a significant increase in the number of satellite cells observed in CLI muscle sections as demonstrated by the expression of pax7 (2.4×?fold p ?Haematopoietic Stem Cells?(HSCs) and satellite cells were also more abundant, with a 2×?fold increase observed (p < 0.0001) whilst those cells expressing both CD34 and pax7 and identified as quiescent satellite cells, were significantly greater in number in the CLI samples (2.9×?fold p < 0.0001), confirmed via immunohistochemistry and protein electrophoresis. There was a significant decrease in the expression of MyoD positive or activated satellite cells (p < 0.0001). This indicates an increase in the proliferation of the satellite cell population as a response to CLI but less active cells are observed.
文摘【目的】目前,越来越多的研究证明环状RNA(circRNA)在牛肌肉发育过程中扮演着重要的角色,但其分子调控机理尚未完善。通过挖掘与牛肌肉发育相关的circRNA的作用机制,为进一步阐明其调控牛肌肉发育的分子机制奠定基础。【方法】以前期分析的增殖期(GM)与成肌分化期(DM)黄牛肌肉干细胞(MuSCs)的RNA-seq测序结果为基础,筛选出显著差异表达的circRNA,circCEP85L。采集新鲜黄牛胎牛的心脏、肝脏、脾脏、肺脏、肾脏、肌肉、肠和胃的组织样本,分离培养黄牛肌肉干细胞并诱导成肌分化,收集黄牛体外培养的GM与DM细胞,分别提取RNA并反转录为cDNA。通过实时荧光定量PCR(quantitative real time PCR,qRT-PCR)检测circCEP85L在不同组织及不同细胞状态的表达规律。同时,设计特异性引物扩增circCEP85L全长,构建过表达载体p-circCEP85L,质粒转染MuSCs后收集过表达circCEP85L细胞样本。以过表达质粒pCD5-ciR细胞样本为对照,采用qRT-PCR、流式细胞术、Western Blot及免疫荧光等技术检测过表达circCEP85L对黄牛MuSCs增殖、凋亡及成肌分化的影响。【结果】PCR电泳结果证明circCEP85L环化位点真实存在。CircCEP85L在多种组织中表达,并在DM期的表达量显著高于GM期(P<0.001);为了进一步探究对circCEP85L黄牛MuSCs的影响。将过表达载体p-circCEP85L与对照载体pCD5-ciR转染体外培养的黄牛MuSCs,继续培养24 h之后,EdU结果表明过表达circCEP85L能显著降低EdU阳性细胞比例(P<0.001);流式周期检测结果表明,过表达circCEP85L增加了G0/G1期细胞比例,显著减少S期细胞比例(P<0.001);流式凋亡结果表明,过表达circCEP85L显著抑制MuSCs的凋亡率(P<0.05)。QRT-PCR及Western blot检测黄牛MuSCs增殖及凋亡相关基因的表达情况,结果表明过表达circCEP85L后显著降低了黄牛MuSCs增殖及凋亡相关基因的mRNA表达水平(P<0.001),凋亡蛋白BAX的表达量也显著降低(P<0.01)。此外,为了
文摘Dedifferentiation, as one of the mechanisms rerouting cell fate, regresses cells from a differentiated status to a more primitive one. Due to its potential of amplifying the stem/progenitor cell pool and reproducing sizable and desirable cellular elements, it has been attended in the field of regenerative medicine, which will hopefully provide novel therapeutic strategies for currently incurable diseases, such as varieties of central nervous system (CNS) diseases and injuries. In this article, we will first discuss naturally occurring and experimentally induced dedifferentiation, and then set forth principles in stem-cell based therapy in the neural field;beyond that, we will introduce two recent studies that show dedifferentiated stem cells contribute to neural regeneration. Moreover, we also present our recent research results of dedifferentiated muscle stem cells for neurogenic differentiation study in vitro. Further work will be conducted to elucidate the mechanism underlying the dedifferentiation process to facilitate the development of new strategies in regenerative medicine.
文摘Androgen doping in power sports is undeniably rampant worldwide. There is strong evidence that androgen administration in men increases skeletal muscle mass, maximal voluntary strength and muscle power. However, we do not have good experimental evidence to support the presumption that androgen administration improves physical function or athletic performance. Androgens do not increase specific force or whole body endurance measures. The anabolic effects of testosterone on the skeletal muscle are mediated through androgen receptor signaling. Testosterone promotes myogenic differentiation of multipotent mesenchymal stem cells and inhibits their differentiation into the adipogenic lineage. Testosterone binding to androgen receptor induces a conformational change in androgen receptor protein, causing it to associate with beta-catenin and TCF-4 and activate downstream Wnt target genes thus promoting myogenic differentiation. The adverse effects of androgens among athletes and recreational bodybuilders are under reported and include acne, deleterious changes in the cardiovascular risk factors, including a marked decrease in plasma high-density lipoproteins （HDL） cholesterol level, suppression of spermatogenesis resulting in infertility, increase in liver enzymes, hepatic neoplasms, mood and behavioral disturbances, and long term suppression of the endogenous hypothalamic-pituitary-gonadal axis. Androgens are often used in combination with other drugs which may have serious adverse events of their own. In spite of effective methods for detecting androgen doping, the policies for screening of athletes are highly variable in different countries and organizations and even existing policies are not uniformly enforced.
文摘Over the last years,the existence of different stem cells with myogenic potential has been widely investigated.Be-sides the classical skeletal muscle progenitors represented by satellite cells,numerous multipotent and embryologi-cally unrelated progenitors with a potential role in muscle differentiation and repair have been identified.In order to conceive a therapeutic approach for degenerative muscle disorders,it is of primary importance to identify an ideal stem cell endowed with all the features for a possible use in vivo.Among all emerging populations,vessel-associated stem cells are a novel and promising class of multipotent progenitors of mesodermal origin and with high myogenic potential which seem to best fit all the requirements for a possible cell therapy.In vitro and in vivo studies have already tested the effectiveness and safety of vessel-associated stem cells in animal models.This leads to the concrete possibility in the future to start pilot human clinical trials,hopefully opening the way to a turn-ing point in the treatment of genetic and acquired muscle disorders.
基金supported by the National Natural Science Foundation of China, No. 30772190Creative Group Project from Education Department of Liaoning Province, No.2009T063
文摘OBJECTIVE： To identify global research trends of muscle-derived stem cells （MDSCs） using a bibliometric analysis of the Web of Science, Research Portfolio Online Reporting Tools of the National Institutes of Health （NIH）, and the Clinical Trials registry database （ClinicalTrials.gov）. DATA RETRIEVAL： We performed a bibliometric analysis of data retrievals for MDSCs from 2002 to 2011 using the Web of Science, NIH, and ClinicalTrials.gov. SELECTION CRITERIA： Inclusion criteria： （1） Web of Science： （a） peer-reviewed articles on MDSCs that were published and indexed in the Web of Science. （b） Type of articles： original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material and news items. （c） Year of publication： 2002-2011. （d） Citation databases： Science Citation Index-Expanded （SCI-E）, 1899-present; Conference Proceedings Citation Index-Science （CPCI-S）, 1991-present; Book Citation Index-Science （BKCI-S）, 2005-present. （2） NIH： （a） Projects on MDSCs supported by the NIH. （b） Fiscal year： 1988-present. （3） ClinicalTrials.gov： All clinical trials relating to MDSCs were searched in this database. Exclusion criteria： （1） Web of Science： （a） Articles that required manual searching or telephone access. （b） We excluded documents that were not published in the public domain. （c） We excluded a number of corrected papers from the total number of articles. （d） We excluded articles from the following databases： Social Sciences Citation Index （SSCI）, 1898-present; Arts ＆ Humanities Citation Index （A＆HCI）, 1975-present; Conference Proceedings Citation Index - Social Science ＆ Humanities （CPCI-SSH）, 1991-present; Book Citation Index - Social Sciences ＆ Humanities （BKCI-SSH）, 2005-present; Current Chemical Reactions （CCR-EXPANDED）, 1985-present; Index Chemicus （IC）, 1993-present. （2） NIH： （a） We excluded publications related to MDSCs that
文摘Bone marrow mesenchymal stem cells (MSCs) can differentiate into smooth muscle cells (SMCs) and have tremendous potential for cell therapy and tissue engineering. In this study, to understand the effects of TGF-β3 on rat bone marrow-derived MSCs and the underlying molecular mechanism of this differentiation process, we investigated that the changes of myocardin-related transcription factors (MRTFs) at the transcriptional level after rat MSCs were treated with TGF-β3. The results showed that TGF-β3 increased the expression of contractile genes, such as SM22, smooth muscle-myosin heavy chain (SM- MHC), SM-α-actin in MSCs. When TGF-β3 induced MSCs differentiation into SMCs, myocardin and MRTF-A were activated. The data indicated that TGF-β3 induced rat bone marrow-derived MSCs differentiation into SMCs by activating mypcardin and MRTF-A.
