技术资料

Mesenchymal stem cells (MSCs) may be used as powerful tools for the repair and regeneration of damaged tissues. However,isolating tissue specific-derived MSCs may cause pain and increased infection rates in patients,and repetitive isolations may be required. To overcome these difficulties,we have examined alternative methods for MSC production. Here,we show that induced pluripotent stem cells (iPSCs) may be differentiated into mesenchymal stem cells (iMSCs) following exposure to SB431542. Purified iMSCs were administered to mdx mice to study skeletal muscle regeneration in a murine model of muscular dystrophy. Purified iMSCs displayed fibroblast-like morphology,formed three-dimensional spheroid structures,and expressed characteristic mesenchymal stem cell surface markers such as CD29,CD33,CD73,CD90,and CD105. Moreover,iMSCs were capable of differentiating into adipogenic,osteogenic,and chondrogenic lineages. Transplanting iMSC cells to tibialis anterior skeletal muscle tissue in mdx mice lowered oxidative damage as evidenced by a reduction in nitrotyrosine levels,and normal dystrophin expression levels were restored. This study demonstrates the therapeutic potential of purified iMSCs in skeletal muscle regeneration in mdx mice,and suggests that iPSCs are a viable alternate source for deriving MSCs as needed. textcopyright 2014 Elsevier Inc. View Publication

BACKGROUND Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are in the foreground as a preferable application for treating diseases. However,the safety of hUC-MSCs after long-term culturing in vitro in serum-free medium remains unclear. METHODS hUC-MSCs were separated by adherent tissue culture. hUC-MSCs were cultured in serum-free MesenCult-XF medium and FBS-bases DMEM complete medium. At the 1st,3rd,5th,8th,10th,and 15th passage,the differentiation of MSCs into osteogenic,chondrogenic,and adipogenic cells was detected,and MTT,surface antigens were measured. Tumorigenicity was analyzed at the 15th passage. Conventional karyotyping was performed at passage 0,8,and 15. The telomerase activity of hUC-MSCs at passage 1-15 was analyzed. RESULTS Flow cytometry analysis showed that very high expression was detected for CD105,CD73,and CD90 and very low expression for CD45,CD34,CD14,CD79a,and HLA-DR. MSCs could differentiate into osteocytes,chondrocytes,and adipocytes in vitro. There was no obvious chromosome elimination,displacement,or chromosomal imbalance as determined from the guidelines of the International System for Human Cytogenetic Nomenclature. Telomerase activity was down-regulated significantly when the culture time was prolonged. Further,no tumors formed in rats injected with hUC-MSCs (P15) cultured in serum-free and in serum-containing conditions. CONCLUSION Our data showed that hUC-MSCs met the International Society for Cellular Therapy standards for conditions of long-term in vitro culturing at P15. Since hUC-MSCs can be safely expanded in vitro and are not susceptible to malignant transformation in serum-free medium,these cells are suitable for cell therapy. View Publication

PURPOSE Demonstrate a novel manufacturing method to generate extracellular matrix scaffolds from cardiac fibroblasts (CF-ECM) as a therapeutic mesenchymal stem cell-transfer device. MATERIALS AND METHODS Rat CF were cultured at high-density (˜1.6×10(5)/cm(2)) for 10-14 days. Cell sheets were removed from the culture dish by incubation with EDTA and decellularized with water and peracetic acid. CF-ECM was characterized by mass spectrometry,immunofluorescence and scanning electron microscopy. CF-ECM seeded with human embryonic stem cell derived mesenchymal stromal cells (hEMSCs) were transferred into a mouse myocardial infarction model. 48 hours later,mouse hearts were excised and examined for CF-ECM scaffold retention and cell transfer. RESULTS CF-ECM scaffolds are composed of fibronectin (82%),collagens type I (13%),type III (3.4%),type V (0.2%),type II (0.1%) elastin (1.3%) and 18 non-structural bioactive molecules. Scaffolds remained intact on the mouse heart for 48 hours without the use of sutures or glue. Identified hEMSCs were distributed from the epicardium to the endocardium. CONCLUSIONS High density cardiac fibroblast culture can be used to generate CF-ECM scaffolds. CF-ECM scaffolds seeded with hEMSCs can be maintained on the heart without suture or glue. hEMSC are successfully delivered throughout the myocardium. View Publication

The purpose of this study was to examine the in vitro and in vivo osteogenic potential of human induced pluripotent stem cells (hiPSCs) against that of human bone marrow mesenchymal stem cells (hBMMSCs). Embryoid bodies (EBs),which were formed from undifferentiated hiPSCs,were dissociated into single cells and underwent osteogenic differentiation using the same medium as hBMMSCs for 14 days. Osteoinduced hiPSCs were implanted on the critical-size calvarial defects and long bone segmental defects in rats. The healing of defects was evaluated after 8 weeks and 12 weeks of implantation,respectively. Osteoinduced hiPSCs showed relatively lower and delayed in vitro expressions of the osteogenic marker COL1A1 and bone sialoprotein,as well as a weaker osteogenic differentiation through alkaline phosphatase staining and mineralization through Alizarin red staining compared with hBMMSCs. Calvarial defects treated with osteoinduced hiPSCs had comparable quality of new bone formation,including full restoration of bone width and robust formation of trabeculae,to those treated with hBMMSCs. Both osteoinduced hiPSCs and hBMMSCs persisted in regenerated bone after 8 weeks of implantation. In critical-size long bone segmental defects,osteoinduced hiPSC treatment also led to healing of segmental defects comparable to osteoinduced hBMMSC treatment after 12 weeks. In conclusion,despite delayed in vitro osteogenesis,hiPSCs have an in vivo osteogenic potential as good as hBMMSCs. View Publication

Mesenchymal stem cells (MSCs) are being tested in a wide range of human diseases; however,loss of potency and inconsistent quality severely limit their use. To overcome these issues,we have utilized a developmental precursor called the hemangioblast as an intermediate cell type in the derivation of a highly potent and replenishable population of MSCs from human embryonic stem cells (hESCs). This method circumvents the need for labor-intensive hand-picking,scraping,and sorting that other hESC-MSC derivation methods require. Moreover,unlike previous reports on hESC-MSCs,we have systematically evaluated their immunomodulatory properties and in vivo potency. As expected,they dynamically secrete a range of bioactive factors,display enzymatic activity,and suppress T-cell proliferation that is induced by either allogeneic cells or mitogenic stimuli. However,they also display unique immunophenotypic properties,as well as a smaller size and textgreater30,000-fold proliferative capacity than bone marrow-derived MSCs. In addition,this is the first report which demonstrates that hESC-MSCs can inhibit CD83 up-regulation and IL-12p70 secretion from dendritic cells and enhance regulatory T-cell populations induced by interleukin 2 (IL-2). This is also the first report which shows that hESC-MSCs have therapeutic efficacy in two different autoimmune disorder models,including a marked increase in survival of lupus-prone mice and a reduction of symptoms in an autoimmune model of uveitis. Our data suggest that this novel and therapeutically active population of MSCs could overcome many of the obstacles that plague the use of MSCs in regenerative medicine and serve as a scalable alternative to current MSC sources. View Publication

Mesenchymal stem cells (MSCs) have a high potential for therapeutic efficacy in treating diverse musculoskeletal injuries and cardiovascular diseases,and for ameliorating the severity of graft-versus-host and autoimmune diseases. While most of these clinical applications require substantial cell quantities,the number of MSCs that can be obtained initially from a single donor is limited. Reports on the derivation of MSC-like cells from pluripotent stem cells (PSCs) are,thus,of interest,as the infinite proliferative capacity of PSCs opens the possibility to generate large amounts of uniform batches of MSCs. However,characterization of such MSC-like cells is currently inadequate,especially with regard to the question of whether these cells are equivalent or identical to MSCs. In this study,we have derived MSC-like cells [induced PSC-derived MSC-like progenitor cells (iMPCs)] using four different methodologies from a newly established induced PSC line reprogrammed from human bone marrow stromal cells (BMSCs),and compared the iMPCs directly with the originating parental BMSCs. The iMPCs exhibited typical MSC/fibroblastic morphology and MSC-typical surface marker profile,and they were capable of differentiation in vitro along the osteogenic,chondrogenic,and adipogenic lineages. However,compared with the parental BMSCs,iMPCs displayed a unique expression pattern of mesenchymal and pluripotency genes and were less responsive to traditional BMSC differentiation protocols. We,therefore,conclude that iMPCs generated from PSCs via spontaneous differentiation represent a distinct population of cells which exhibit MSC-like characteristics. View Publication

Administration of bone marrow-derived mesenchymal stem cells (MSCs) is an innovative approach for the treatment of a range of diseases that are not curable by current therapies including heart failure. A number of clinical trials have been completed and many others are ongoing; more than 2,000 patients worldwide have been administered with culture-expanded allogeneic or autologous MSCs for the treatment of various diseases,showing feasibility and safety (and some efficacy) of this approach. However,protocols for isolation and expansion of donor MSCs vary widely between these trials,which could affect the efficacy of the therapy. It is therefore important to develop international standards of MSC production,which should be evidence-based,regulatory authority-compliant,of good medical practice grade,cost-effective,and clinically practical,so that this innovative approach becomes an established widely adopted treatment. This review article summarizes protocols to isolate and expand bone marrow-derived MSCs in 47 recent clinical trials of MSC-based therapy,which were published after 2007 onwards and provided sufficient methodological information. Identified issues and possible solutions associated with the MSC production methods,including materials and protocols for isolation and expansion,are discussed with reference to relevant experimental evidence with aim of future clinical success of MSC-based therapy. View Publication

Many different culture systems have been developed for expanding human pluripotent stem cells (hESCs and hiPSCs). In general,4-10 ng/ml of bFGF is supplemented in culture media in feeder-dependent systems regardless of feeder cell types,whereas in feeder-free systems,up to 100 ng/ml of bFGF is required for maintaining long-term culture on various substrates. The amount of bFGF required in native hESCs growth niche is unclear. Here we report using inactivated adipose-derived human mesenchymal stem cells as feeder cells to examine long-term parallel cultures of two hESCs lines (H1 and H9) and one hiPSCs line (DF19-9-7T) in media supplemented with 0,0.4 or 4 ng/ml of bFGF for up to 23 passages,as well as parallel cultures of H9 and DF19 in media supplemented with 4,20 or 100 ng/ml bFGF for up to 13 passages for comparison. Across all cell lines tested,bFGF supplement demonstrated inhibitory effect over growth expansion,single cell colonization and recovery from freezing in a dosage dependent manner. In addition,bFGF exerted differential effects on different cell lines,inducing H1 and DF19 differentiation at 4 ng/ml or higher,while permitting long-term culture of H9 at the same concentrations with no apparent dosage effect. Pluripotency was confirmed for all cell lines cultured in 0,0.4 or 4 ng/ml bFGF excluding H1-4 ng,as well as H9 cultured in 4,20 and 100 ng/ml bFGF. However,DF19 demonstrated similar karyotypic abnormality in both 0 and 4 ng/ml bFGF media while H1 and H9 were karyotypically normal in 0 ng/ml bFGF after long-term culture. Our results indicate that exogenous bFGF exerts dosage and cell line dependent effect on human pluripotent stem cells cultured on mesenchymal stem cells,and implies optimal use of bFGF in hESCs/hiPSCs culture should be based on specific cell line and its culture system. View Publication

Mesenchymal stem cells (MSCs) are multipotent adult stem cells that have an immunosuppressive effect. The biological stability of MSCs in serum-free medium during long-term culture in vitro has not been elucidated clearly. The morphology,immunophenotype and multi-lineage potential were analyzed at passages 3,5,10,15,20,and 25 (P3,P5,P10,P15,P20,and P25,respectively). The cell cycle distribution,apoptosis,and karyotype of human umbilical cord-derived (hUC)-MSCs were analyzed at P3,P5,P10,P15,P20,and P25. From P3 to P25,the three defining biological properties of hUC-MSCs [adherence to plastic,specific surface antigen expression,multipotent differentiation potential] met the standards proposed by the International Society for Cellular Therapy for definition of MSCs. The cell cycle distribution analysis at the P25 showed that the percentage of cells at G0/G1 was increased,compared with the cells at P3 (P textless 0.05). Cells at P25 displayed an increase in the apoptosis rate (to 183 %),compared to those at P3 (P textless 0.01). Within subculture generations 3-20 (P3-P20),the differences between the cell apoptotic rates were not statistically significant (P textgreater 0.05). There were no detectable chromosome eliminations,displacements,or chromosomal imbalances,as assessed by the karyotyping guidelines of the International System for Human Cytogenetic Nomenclature (ISCN,2009). Long-term culture affects the biological stability of MSCs in serum-free MesenCult-XF medium. MSCs can be expanded up to the 25th passage without chromosomal changes by G-band. The best biological activity period and stability appeared between the third to 20th generations. View Publication

There is a great deal of uncertainty on how low (≤ 0.1 Gy) doses of ionizing radiation (IR) affect human cells,partly due to a lack of suitable experimental model systems for such studies. The uncertainties arising from low-dose IR human data undermine practical societal needs to predict health risks emerging from diagnostic medical tests' radiation,natural background radiation,and environmental radiological accidents. To eliminate a variability associated with remarkable differences in radioresponses of hundreds of differentiated cell types,we established a novel,human embryonic stem cell (hESC)-based model to examine the radiobiological effects in human cells. Our aim is to comprehensively elucidate the gene expression changes in a panel of various hESC lines following low IR doses of 0.01; 0.05; 0.1 Gy; and,as a reference,relatively high dose of 1 Gy of IR. Here,we examined the dynamics of transcriptional changes of well-established IR-responsive set of genes,including CDKN1A,GADD45A,etc. at 2 and 16 h post-IR,representing early" and "late" radioresponses of hESCs. Our findings suggest the temporal- and hESC line-dependence of stress gene radioresponses with no statistically significant evidence for a linear dose-response relationship within the lowest doses of IR exposures." View Publication

Structural bone allografts are widely used in the clinic to treat critical sized bone defects,despite lacking the osteoinductive characteristics of live autografts. To address this,we generated revitalized structural allografts wrapped with mesenchymal stem/progenitor cell (MSC) sheets,which were produced by expanding primary syngenic bone marrow derived cells on temperature-responsive plates,as a tissue-engineered periosteum. In vitro assays demonstrated maintenance of the MSC phenotype in the sheets,suggesting that short-term culturing of MSC sheets is not detrimental. To test their efficacy in vivo,allografts wrapped with MSC sheets were transplanted into 4-mm murine femoral defects and compared to allografts with direct seeding of MSCs and allografts without cells. Evaluations consisted of X-ray plain radiography,3D microCT,histology,and biomechanical testing at 4- and 6-weeks post-surgery. Our findings demonstrate that MSC sheets induce prolonged cartilage formation at the graft-host junction and enhanced bone callus formation,as well as graft-host osteointegration. Moreover,a large periosteal callus was observed spanning the allografts with MSC sheets,which partially mimics live autograft healing. Finally,biomechanical testing showed a significant increase in the structural and functional properties of MSC sheet grafted femurs. Taken together,MSC sheets exhibit enhanced osteogenicity during critical sized bone defect repair,demonstrating the feasibility of this tissue engineering solution for massive allograft healing. View Publication

Findings from studies on stem cells have been applied to cancer stem cell (CSC) research,but little is known about the relationship between ES cell-related cell surface markers and CSCs. In this study,we focused on stage-specific embryonic antigen 3 (SSEA-3),a marker of mesenchymal stem cells and Muse cells in colorectal cancer (CRC). Expression of SSEA-3 in human CRC cell lines and clinical specimens,specifically the relationship of SSEA-3 expression and the representative CSC markers (CD44,CD166,ALDH,CD24 and CD26) as well as with mesenchymal stem cell/Muse cell marker (CD105) were assessed. To characterize SSEA-3-expressing cells,tumorigenicity,sphere formation ability,expression of iPS genes (Oct4,NANOG,SOX2 and c-Myc),cell proliferation and cell cycle status were assessed. SSEA-3 expression was identified in Caco-2,DLD-1,HT-29,SW480 and HCT116,but not in CaR-1 cells. No significant relationship between SSEA-3 and other stem cell markers was detected. SSEA-3+ cells showed increased tumorigenicity in vivo,but lower sphere formation ability in vitro than SSEA-3-. iPS gene expression was not correlated with SSEA-3 expression status. SSEA-3+ cells showed higher proliferative ability than SSEA-3- through enhanced cell cycles by decreased expression of p21Cip1/Waf1 and p27Kip1. Immunofluorescence analysis in clinical specimens indicated that expression of SSEA-3 is limited to stromal cells in normal mucosa but broad in poorly differentiated adenocarcinoma. These observations indicated that SSEA-3+ cells in CRC have immature phenotype but decreased self-renewal ability and may function as tumor transient amplifying cells or delayed contributing tumor-initiating cells. View Publication