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

Umbilical cord blood (UCB) is increasingly being used for human hematopoietic stem cell (HSC) transplantation in children but often requires pooling multiple cords to obtain sufficient numbers for transplantation in adults. To overcome this limitation,we have used an ex vivo two-week culture system to expand the number of hematopoietic CD34(+) cells in cord blood. To assess the in vivo function of these expanded CD34(+) cells,cultured human UCB containing 1 x 10(6) CD34(+) cells were transplanted into conditioned NOD-scid IL2rgamma(null) mice. The expanded CD34(+) cells displayed short- and long-term repopulating cell activity. The cultured human cells differentiated into myeloid,B-lymphoid,and erythroid lineages,but not T lymphocytes. Administration of human recombinant TNFalpha to recipient mice immediately prior to transplantation promoted human thymocyte and T-cell development. These T cells proliferated vigorously in response to TCR cross-linking by anti-CD3 antibody. Engrafted TNFalpha-treated mice generated antibodies in response to T-dependent and T-independent immunization,which was enhanced when mice were co-treated with the B cell cytokine BLyS. Ex vivo expanded CD34(+) human UCB cells have the capacity to generate multiple hematopoietic lineages and a functional human immune system upon transplantation into TNFalpha-treated NOD-scid IL2rgamma(null) mice. View Publication

Aldehyde dehydrogenase 1A1 (ALDH) activity is one hallmark of human bone marrow (BM),umbilical cord blood (UCB),and peripheral blood (PB) primitive progenitors presenting high reconstitution capacities in vivo. In this study,we have identified ALDH(+) cells within human skeletal muscles,and have analyzed their phenotypical and functional characteristics. Immunohistofluorescence analysis of human muscle tissue sections revealed rare endomysial cells. Flow cytometry analysis using the fluorescent substrate of ALDH,Aldefluor,identified brightly stained (ALDH(br)) cells with low side scatter (SSC(lo)),in enzymatically dissociated muscle biopsies,thereafter abbreviated as SMALD(+) (for skeletal muscle ALDH(+)) cells. Phenotypical analysis discriminated two sub-populations according to CD34 expression: SMALD(+)/CD34(-) and SMALD(+)/CD34(+) cells. These sub-populations did not initially express endothelial (CD31),hematopoietic (CD45),and myogenic (CD56) markers. Upon sorting,however,whereas SMALD(+)/CD34(+) cells developed in vitro as a heterogeneous population of CD56(-) cells able to differentiate in adipoblasts,the SMALD(+)/CD34(-) fraction developed in vitro as a highly enriched population of CD56(+) myoblasts able to form myotubes. Moreover,only the SMALD(+)/CD34(-) population maintained a strong myogenic potential in vivo upon intramuscular transplantation. Our results suggest that ALDH activity is a novel marker for a population of new human skeletal muscle progenitors presenting a potential for cell biology and cell therapy. View Publication

Neuronal conversion from human fibroblasts can be induced by lineage-specific transcription factors; however,the introduction of ectopic genes limits the therapeutic applications of such induced neurons (iNs). Here,we report that human fibroblasts can be directly converted into neuronal cells by a chemical cocktail of seven small molecules,bypassing a neural progenitor stage. These human chemical-induced neuronal cells (hciNs) resembled hiPSC-derived neurons and human iNs (hiNs) with respect to morphology,gene expression profiles,and electrophysiological properties. This approach was further applied to generate hciNs from familial Alzheimer's disease patients. Taken together,our transgene-free and chemical-only approach for direct reprogramming of human fibroblasts into neurons provides an alternative strategy for modeling neurological diseases and for regenerative medicine. View Publication

Efficient derivation of endothelial cells and their progenitors from human pluripotent stem cells (hPSCs) can facilitate studies of human vascular development,disease modeling,drug discovery,and cell-based therapy. Here we provide a detailed protocol for directing hPSCs to functional endothelial cells and their progenitors in a completely defined,growth factor- and serum-free system by temporal modulation of Wnt/$$-catenin signaling via small molecules. We demonstrate a 10-day,two-stage process that recapitulates endothelial cell development,in which hPSCs first differentiate to endothelial progenitors that then generate functional endothelial cells and smooth muscle cells. Methods to characterize endothelial cell identity and function are also described. View Publication

The creation of a humanized chimeric mouse nervous system permits the study of human neural development and disease pathogenesis using human cells in vivo. Humanized glial chimeric mice with the brain and spinal cord being colonized by human glial cells have been successfully generated. However,generation of humanized chimeric mouse brains repopulated by human neurons to possess a high degree of chimerism have not been well studied. Here we created humanized neuronal chimeric mouse brains by neonatally engrafting the distinct and highly neurogenic human induced pluripotent stem cell (hiPSC)-derived rosette-type primitive neural progenitors. These neural progenitors predominantly differentiate to neurons,which disperse widely throughout the mouse brain with infiltration of the cerebral cortex and hippocampus at 6 and 13 months after transplantation. Building upon the hiPSC technology,we propose that this potentially unique humanized neuronal chimeric mouse model will provide profound opportunities to define the structure,function,and plasticity of neural networks containing human neurons derived from a broad variety of neurological disorders. View Publication

Aging is known to be the single most important risk factor for multiple diseases. Sirtuin 6,or SIRT6,has recently been identified as a critical regulator of transcription,genome stability,telomere integrity,DNA repair,and metabolic homeostasis. A knockout mouse model of SIRT6 has displayed dramatic phenotypes of accelerated aging. In keeping with its role in aging,we demonstrated that human dermal fibroblasts (HDFs) from older human subjects were more resistant to reprogramming by classic Yamanaka factors than those from younger human subjects,but the addition of SIRT6 during reprogramming improved such efficiency in older HDFs substantially. Despite the importance of SIRT6,little is known about the molecular mechanism of its regulation. We show,for the first,time posttranscriptional regulation of SIRT6 by miR-766 and inverse correlation in the expression of this microRNA in HDFs from different age groups. Our results suggest that SIRT6 regulates miR-766 transcription via a feedback regulatory loop,which has implications for the modulation of SIRT6 expression in reprogramming of aging cells. View Publication

Human pluripotent stem cell (hPSC) differentiation typically yields heterogeneous populations. Knowledge of signals controlling embryonic lineage bifurcations could efficiently yield desired cell types through exclusion of alternate fates. Therefore,we revisited signals driving induction and anterior-posterior patterning of definitive endoderm to generate a coherent roadmap for endoderm differentiation. With striking temporal dynamics,BMP and Wnt initially specified anterior primitive streak (progenitor to endoderm),yet,24 hr later,suppressed endoderm and induced mesoderm. At lineage bifurcations,cross-repressive signals separated mutually exclusive fates; TGF-?? and BMP/MAPK respectively induced pancreas versus liver from endoderm by suppressing the alternate lineage. We systematically blockaded alternate fates throughout multiple consecutive bifurcations,thereby efficiently differentiating multiple hPSC lines exclusively into endoderm and its derivatives. Comprehensive transcriptional and chromatin mapping of highly pure endodermal populations revealed that endodermal enhancers existed in a surprising diversity of pre-enhancer" states before activation� View Publication

Incurable neurological disorders such as Parkinson's disease (PD),Huntington's disease (HD),and Alzheimer's disease (AD) are very common and can be life-threatening because of their progressive disease symptoms with limited treatment options. To provide an alternative renewable cell source for cell-based transplantation and as study models for neurological diseases,we generated induced pluripotent stem cells (iPSCs) from human dermal fibroblasts (HDFs) and then differentiated them into neural progenitor cells (NPCs) and mature neurons by dual SMAD signaling inhibitors. Reprogramming efficiency was improved by supplementing the histone deacethylase inhibitor,valproic acid (VPA),and inhibitor of p160-Rho associated coiled-coil kinase (ROCK),Y-27632,after retroviral transduction. We obtained a number of iPS colonies that shared similar characteristics with human embryonic stem cells in terms of their morphology,cell surface antigens,pluripotency-associated gene and protein expressions as well as their in vitro and in vivo differentiation potentials. After treatment with Noggin and SB431542,inhibitors of the SMAD signaling pathway,HDF-iPSCs demonstrated rapid and efficient differentiation into neural lineages. Six days after neural induction,neuroepithelial cells (NEPCs) were observed in the adherent monolayer culture,which had the ability to differentiate further into NPCs and neurons,as characterized by their morphology and the expression of neuron-specific transcripts and proteins. We propose that our study may be applied to generate neurological disease patient-specific iPSCs allowing better understanding of disease pathogenesis and drug sensitivity assays. View Publication

BACKGROUND: Endothelial cells line the luminal surface of blood vessels and form a barrier between the blood and other tissues of the body. Ets variant 2 (ETV2) is transiently expressed in both zebrafish and mice and is necessary and sufficient for vascular endothelial cell specification. Overexpression of this gene in early zebrafish and mouse embryos results in ectopic appearance of endothelial cells. Ectopic expression of ETV2 in later development results in only a subset of cells responding to the signal.backslashnbackslashnFINDINGS: We have examined the expression pattern of ETV2 in differentiating human embryonic stem cells (ESCs) to determine when the peak of ETV2 expression occurs. We show that overexpression of ETV2 in differentiating human ESC is able to increase the number of endothelial cells generated when administered during or after the endogenous peak of gene expression.backslashnbackslashnCONCLUSIONS: Addition of exogenous ETV2 to human ESCs significantly increased the number of cells expressing angioblast genes without arterial or venous specification. This may be a viable solution to generate in vitro endothelial cells for use in research and in the clinic. View Publication

Zika virus (ZIKV) infection has been associated with severe complications both in the developing and adult nervous system. To investigate the deleterious effects of ZIKV infection,we used human neural progenitor cells (NPC),derived from induced pluripotent stem cells (iPSC). We found that NPC are highly susceptible to ZIKV and the infection results in cell death. ZIKV infection led to a marked reduction in cell proliferation,ultrastructural alterations and induction of autophagy. Induction of apoptosis of Sox2 + cells was demonstrated by activation of caspases 3/7,8 and 9,and by ultrastructural and flow cytometry analyses. ZIKV-induced death of Sox2 + cells was prevented by incubation with the pan-caspase inhibitor,Z-VAD-FMK. By confocal microscopy analysis we found an increased number of cells with supernumerary centrosomes. Live imaging showed a significant increase in mitosis abnormalities,including multipolar spindle,chromosome laggards,micronuclei and death of progeny after cell division. FISH analysis for chromosomes 12 and 17 showed increased frequency of aneuploidy,such as monosomy,trisomy and polyploidy. Our study reinforces the link between ZIKV and abnormalities in the developing human brain,including microcephaly. View Publication