搜索结果: 'methocult media formulations for mouse hematopoietic cells serum containing'

Human embryonic stem cells (hESCs) can be maintained in vitro as immortal pluripotent cells but remain responsive to many differentiation-inducing signals. Investigation of the initial critical events involved in differentiation induction would be greatly facilitated if a specific,robust,and quantitative assay for pluripotent hESCs with self-renewal potential were available. Here we describe the results of a series of experiments to determine whether the formation of adherent alkaline phosphatase-positive (AP(+)) colonies under conditions optimized for propagating undifferentiated hESCs would meet this need. The findings can be summarized as follows. (a) Most colonies obtained under these conditions consist of textgreateror=30 AP(+) cells that coexpress OCT4,NANOG,SSEA3,SSEA4,TRA-1-60,and TRA-1-81. (b) Most such colonies are derived from SSEA3(+) cells. (c) Primary colonies contain cells that produce secondary colonies of the same composition,including cells that initiate multilineage differentiation in embryoid bodies (EBs). (d) Colony formation is independent of plating density or the colony-forming cell (CFC) content of the test population over a wide range of cell concentrations. (e) CFC frequencies decrease when differentiation is induced by exposure either to retinoic acid or to conditions that stimulate EB formation. Interestingly,this loss of AP(+) clonogenic potential also occurs more rapidly than the loss of SSEA3 or OCT4 expression. The CFC assay thus provides a simple,reliable,broadly applicable,and highly specific functional assay for quantifying undifferentiated hESCs with self-renewal potential. Its use under standardized assay conditions should enhance future elucidation of the mechanisms that regulate hESC propagation and their early differentiation. View Publication

We have previously demonstrated that lineage negative cells (Lin(neg)) from umbilical cord blood (UCB) develop into multipotent cells capable of differentiation into bone,muscle,endothelial and neural cells. The objective of this study was to determine the optimal conditions required for Lin(neg) UCB cells to differentiate into neuronal cells and oligodendrocytes. We demonstrate that early neural stage markers (nestin,neurofilament,A2B5 and Sox2) are expressed in Lin(neg) cells cultured in FGF4,SCF,Flt3-ligand reprogramming culture media followed by the early macroglial cell marker O4. Early stage oligodendrocyte markers CNPase,GalC,Olig2 and the late-stage marker MOSP are observed,as is the Schwann cell marker PMP22. In summary,Lin(neg) UCB cells,when appropriately cultured,are able to exhibit characteristics of neuronal and macroglial cells that can specifically differentiate into oligodendrocytes and Schwann cells and express proteins associated with myelin production after in vitro differentiation. View Publication

A simple,scalable,and reproducible technology that allows direct formation of large numbers of homogeneous and synchronized embryoid bodies (EBs) of defined sizes from dissociated human induced pluripotent stem cells (hiPSCs) was developed. Non-cell-adhesive hydrogels were used to create round-bottom microwells to host dissociated hiPSCs. No Rho-associated kinase inhibitor (ROCK-i),or centrifugation was needed and the side effects of ROCK-i can be avoided. The key requirement for the successful EB formation in addition to the non-cell-adhesive round-bottom microwells is the input cell density per microwell. Too few or too many cells loaded into the microwells will compromise the EB formation process. In parallel,we have tested our microwell-based system for homogeneous hEB formation from dissociated human embryonic stem cells (hESCs). Successful production of homogeneous hEBs from dissociated hESCs in the absence of ROCK-i and centrifugation was achieved within an optimal range of input cell density per microwell. Both the hiPSC- and hESC-derived hEBs expressed key proteins characteristic of all the three developmental germ layers,confirming their EB identity. This novel EB production technology may represent a versatile platform for the production of homogeneous EBs from dissociated human pluripotent stem cells (hPSCs). View Publication

Adaptive immunity to self-antigens causes autoimmune disorders,such as multiple sclerosis,psoriasis and type 1 diabetes; paradoxically,T- and B-cell responses to amyloid-$\$(A$\$) reduce Alzheimer's disease (AD)-associated pathology and cognitive impairment in mouse models of the disease. The manipulation of adaptive immunity has been a promising therapeutic approach for the treatment of AD,although vaccine and anti-A$\$ approaches have proven difficult in patients,thus far. CD4(+) T cells have a central role in regulating adaptive immune responses to antigens,and A$\$-specific CD4(+) T cells have been shown to reduce AD pathology in mouse models. As these cells may facilitate endogenous mechanisms that counter AD,an evaluation of their abundance before and during AD could provide important insights. A$\$-CD4see is a new assay developed to quantify A$\$-specific CD4(+) T cells in human blood,using dendritic cells derived from human pluripotent stem cells. In tests of textgreater50 human subjects A$\$-CD4see showed an age-dependent decline of A$\$-specific CD4(+) T cells,which occurs earlier in women than men. In aggregate,men showed a 50% decline in these cells by the age of 70 years,but women reached the same level before the age of 60 years. Notably,women who carried the AD risk marker apolipoproteinE-ɛ4 (ApoE4) showed the earliest decline,with a precipitous drop between 45 and 52 years,when menopause typically begins. A$\$-CD4see requires a standard blood draw and provides a minimally invasive approach for assessing changes in A$\$ that may reveal AD-related changes in physiology by a decade. Furthermore,CD4see probes can be modified to target any peptide,providing a powerful new tool to isolate antigen-specific CD4(+) T cells from human subjects. View Publication

The development of xeno-free,chemically defined stem cell culture systems has been a primary focus in the field of regenerative medicine to enhance the clinical application of pluripotent stem cells (PSCs). In this regard,various electrospun substrates with diverse physiochemical properties were synthesized utilizing various polymer precursors and surface treatments. Human induced pluripotent stem cells (IPSCs) cultured on these substrates were characterized by their gene and protein expression to determine the effects of the substrate physiochemical properties on the cells' self-renewal,i.e.,proliferation and the maintenance of pluripotency. The results showed that surface chemistry significantly affected cell colony formation via governing the colony edge propagation. More importantly,when surface chemistry of the substrates was uniformly controlled by collagen conjugation,the stiffness of substrate was inversely related to the sphericity,a degree of three dimensionality in colony morphology. The differences in sphericity subsequently affected spontaneous differentiation of IPSCs during a long-term culture,implicating that the colony morphology is a deciding factor in the lineage commitment of PSCs. Overall,we show that the capability of controlling IPSC colony morphology by electrospun substrates provides a means to modulate IPSC self-renewal. View Publication

BACKGROUND: Serum-free cultures supplemented with stem cell factor (SCF) and IL-6 is reported to support the extensive growth of less functional human cord blood-derived mast cells. OBJECTIVE: To obtain more functional mast cells from cord blood,we developed a culture system combining a serum-free condition for 0-8 weeks of culture,and followed by a serum-supplemented culture condition and examined the function of the cells compared to the cells cultured continuously in serum-free condition. METHODS: Human cord blood progenitors were purified with anti-CD133 antibody. They were cultured in a serum-free medium StemSpan supplemented with SCF at 100 ng/ml and IL-6 at 50 ng/ml for 8 weeks. Then,an aliquot of the cultured cells were cultured in the above condition but further supplemented with 10% fetal calf serum (FCS). RESULTS: The addition of FCS after 8 weeks of culture significantly increased the amount of histamine per mast cell (3.8 pg/cell) when compared to the serum-free condition (0.7 pg/cell). The cells cultured with FCS after 8 weeks expressed more FcvarepsilonRI alpha and released textgreater30% of the histamine content upon anti-IgE stimulation than those cultured without serum. CONCLUSION: It is uncertain why FCS enhanced the functional maturation of mast cells when added after week 8 of culture but suppressed mast cell development when added at day 0 of culture. Yet,the present method combining a serum-free culture system with a serum-supplemented culture system seems to be beneficial for most of the laboratories to obtain functional human mast cells. View Publication

Human pluripotent stem cell (hPSC)-derived endothelial lineage cells constitutes a promising source for therapeutic revascularization,but progress in this arena has been hampered by a lack of clinically-scalable differentiation protocols and inefficient formation of a functional vessel network integrating with the host circulation upon transplantation. Using a human embryonic stem cell reporter cell line,where green fluorescent protein expression is driven by an endothelial cell-specific VE-cadherin (VEC) promoter,we screened for textgreater 60 bioactive small molecules that would promote endothelial differentiation,and found that administration of BMP4 and a GSK-3β inhibitor in an early phase and treatment with VEGF-A and inhibition of the Notch signaling pathway in a later phase led to efficient differentiation of hPSCs to the endothelial lineage within six days. This sequential approach generated textgreater 50% conversion of hPSCs to endothelial cells (ECs),specifically VEC(+)CD31(+)CD34(+)CD14(-)KDR(high) endothelial progenitors (EPs) that exhibited higher angiogenic and clonogenic proliferation potential among endothelial lineage cells. Pharmaceutical inhibition or genetical knockdown of Notch signaling,in combination with VEGF-A treatment,resulted in efficient formation of EPs via KDR(+) mesodermal precursors and blockade of the conversion of EPs to mature ECs. The generated EPs successfully formed functional capillary vessels in vivo with anastomosis to the host vessels when transplanted into immunocompromised mice. Manipulation of this VEGF-A-Notch signaling circuit in our protocol leads to rapid large-scale production of the hPSC-derived EPs by 12- to 20-fold vs current methods,which may serve as an attractive cell population for regenerative vascularization with superior vessel forming capability compared to mature ECs. View Publication

Improvement of methods to produce endoderm-derived cells from pluripotent stem cells is important to realize high-efficient induction of endodermal tissues such as pancreas and hepatocyte. Difficulties hampering such efforts include the low efficiency of definitive endoderm cell induction and establishing appropriate defined culture conditions to ensure a safe cell source for human transplantation. Based on previous studies,we revised the experimental condition of definitive endoderm induction in feeder- and serum-free culture. Our results suggested that CHIR99021 is more effective than Wnt3A ligand in feeder- and serum-free conditions. In addition,keeping cell density low during endoderm induction is important for the efficiency. On the other hand,we showed that overtreatment with CHIR99021 converted the cells into BRACHYURY-expressing posterior mesoderm cells rather than endoderm,indicating strict CHIR99021 treatment requirements for endoderm differentiation. Nevertheless,these results should enable better control in the production of definitive endoderm-derived cells. View Publication

This study was designed to investigate one component of the Wnt/beta-catenin signaling pathway that has been implicated in stem cell self-renewal. Retroviral-mediated introduction of stable beta-catenin to primitive murine bone marrow cells allowed the expansion of multipotential c-Kit(low)Sca-1(low/-)CD19(-) CD11b/Mac-1(-)Flk-2(-)CD43(+)AA4.1(+)NK1.1(-)CD3(-)CD11c(-)Gr-1(-)CD45R/B220(+) cells in the presence of stromal cells and cytokines. They generated myeloid,T,and B lineage lymphoid cells in culture,but had no T lymphopoietic potential when transplanted. Stem cell factor and IL-6 were found to be minimal requirements for long-term,stromal-free propagation,and a beta-catenin-transduced cell line was maintained for 5 mo with these defined conditions. Although multipotential and responsive to many normal stimuli in culture,it was unable to engraft several types of irradiated recipients. These findings support previous studies that have implicated the canonical Wnt pathway signaling in regulation of multipotent progenitors. In addition,we demonstrate how it may be experimentally manipulated to generate valuable cell lines. View Publication

Osteoblasts play a crucial role in the hematopoietic stem cell (HSC) niche; however,an overall increase in their number does not necessarily promote hematopoiesis. Because the activity of osteoblasts and osteoclasts is coordinately regulated,we hypothesized that active bone-resorbing osteoclasts would participate in HSC niche maintenance. Mice treated with bisphosphonates exhibited a decrease in proportion and absolute number of Lin(-)cKit(+)Sca1(+) Flk2(-) (LKS Flk2(-)) and long-term culture-initiating cells in bone marrow (BM). In competitive transplantation assays,the engraftment of treated BM cells was inferior to that of controls,confirming a decrease in HSC numbers. Accordingly,bisphosphonates abolished the HSC increment produced by parathyroid hormone. In contrast,the number of colony-forming-unit cells in BM was increased. Because a larger fraction of LKS in the BM of treated mice was found in the S/M phase of the cell cycle,osteoclast impairment makes a proportion of HSCs enter the cell cycle and differentiate. To prove that HSC impairment was a consequence of niche manipulation,a group of mice was treated with bisphosphonates and then subjected to BM transplantation from untreated donors. Treated recipient mice experienced a delayed hematopoietic recovery compared with untreated controls. Our findings demonstrate that osteoclast function is fundamental in the HSC niche. View Publication

BACKGROUND: Abnormal activation of endochondral bone formation in soft tissues causes significant medical diseases associated with disability and pain. Hyperactive mutations in the bone morphogenetic protein (BMP) type 1 receptor ACVR1 lead to fibrodysplasia ossificans progressiva (FOP),a rare genetic disorder characterized by progressive ossification in soft tissues. However,the specific cellular mechanisms are unclear. In addition,the difficulty obtaining tissue samples from FOP patients and the limitations in mouse models of FOP hamper our ability to dissect the pathogenesis of FOP.backslashnbackslashnMETHODS: To address these challenges and develop a disease model in a dish"� 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