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

Priming of human NK cells with IL-2 is necessary to render them functionally competent upon NKG2D engagement. We examined the underlying mechanisms that control NKG2D responsiveness in NK cells and found that IL-2 upregulates expression of the amino acid transporters SLC1A5 and CD98. Using specific inhibitors to block SLC1A5 and CD98 function,we found that production of IFN-γ and degranulation by CD56bright and CD56dim NK cells following NKG2D stimulation were dependent on both transporters. IL-2 priming increased the activity of mTORC1,and inhibition of mTORC1 abrogated the ability of the IL-2-primed NK cells to produce IFN-γ in response to NKG2D-mediated stimulation. This study identifies a series of IL-2-induced cellular changes that regulates the NKG2D responsiveness in human NK cells. View Publication

Differentiating embryonic stem (ES) cells are an increasingly important source of hematopoietic progenitors,useful for both basic research and clinical applications. Besides their characterization in colony assays,protocols exist for the cultivation of lymphoid,myeloid,and erythroid cells. With the possible exception of mast cells,however,long-term expansion of pure hematopoietic progenitors from ES cells has not been possible without immortalization caused by overexpression of exogenous genes. Here,we describe for the first time an efficient yet easy strategy to generate mass cultures of pure,immature erythroid progenitors from mouse ES cells (ES-EPs),using serum-free medium plus recombinant cytokines and hormones. ES-EPs represent long-lived,adult,definitive erythroid progenitors that resemble immature erythroid cells expanding in vivo during stress erythropoiesis. When exposed to terminal differentiation conditions,ES-EPs differentiated into mature,enucleated erythrocytes. Importantly,ES-EPs injected into mice did not exhibit tumorigenic potential but differentiated into normal erythrocytes. Both the virtually unlimited supply of cells and the defined culture conditions render our system a valuable tool for the analysis of factors influencing proliferation and maturation of erythroid progenitors. In addition,the system allows detailed characterization of processes during erythroid proliferation and differentiation using wild-type (wt) and genetically modified ES cells. View Publication

Dax-1 (Nr0b1) is an orphan member of the nuclear hormone receptor superfamily that has a key role in adrenogonadal development and function. Recent studies have also implicated Dax-1 in the transcriptional network controlling embryonic stem (ES) cell pluripotency. Here,we show that Dax-1 expression is affected by differentiating treatments and pharmacological activation of beta-catenin-dependent transcription in mouse ES cells. Furthermore,Dax-1 knockdown induced upregulation of multilineage differentiation markers,and produced enhanced differentiation and defects in ES viability and proliferation. Through RNA interference and transcriptome analysis,we have identified genes regulated by Dax-1 in mouse ES cells at 24 and 48 hours after knockdown. Strikingly,the great majority of these genes are upregulated,showing that the prevalent function of Dax-1 is to act as a transcriptional repressor in mouse ES cells,as confirmed by experiments using the Gal4 system. Genes involved in tissue differentiation and control of proliferation are significantly enriched among Dax-1-regulated transcripts. These data show that Dax-1 is an essential element in the molecular circuit involved in the maintenance of ES cell pluripotency and have implications for the understanding of stem cell function in both physiological (adrenal gland) and clinical (Ewing tumors) settings where Dax-1 plays a pivotal role in development and pathogenesis,respectively. View Publication

Understanding human embryonic ventral midbrain is of major interest for Parkinson's disease. However,the cell types,their gene expression dynamics,and their relationship to commonly used rodent models remain to be defined. We performed single-cell RNA sequencing to examine ventral midbrain development in human and mouse. We found 25 molecularly defined human cell types,including five subtypes of radial glia-like cells and four progenitors. In the mouse,two mature fetal dopaminergic neuron subtypes diversified into five adult classes during postnatal development. Cell types and gene expression were generally conserved across species,but with clear differences in cell proliferation,developmental timing,and dopaminergic neuron development. Additionally,we developed a method to quantitatively assess the fidelity of dopaminergic neurons derived from human pluripotent stem cells,at a single-cell level. Thus,our study provides insight into the molecular programs controlling human midbrain development and provides a foundation for the development of cell replacement therapies. View Publication

In the field of hematopoietic regeneration,deriving hematopoietic stem cells (HSCs) from pluripotent stem cells with engraftment potential is the central mission. Unstable hematopoietic differentiation protocol due to variation factors such as serums and feeder cells,remains a major technical issue impeding the screening of key factors for the derivation of HSCs. In combination with hematopoietic cytokines,UM171 has the capacity to facilitate the maintenance and expansion of human primary HSCs in vitro. Here,using a serum-free,feeder-free,and chemically defined induction protocol,we observed that UM171 enhanced hematopoietic derivation through the entire process of hematopoietic induction in vitro. UM171 facilitated generation of robust CD34(+)CD45(+) derivatives that formed more and larger sized CFU-GM as well as larger sized CFU-Mix. In our protocol,the derived hematopoietic progenitors failed to engraft in NOG mice,indicating the absence of long-term HSC from these progenitors. In combination with other factors and protocols,UM171 might be broadly used for hematopoietic derivation from human pluripotent stem cells in vitro. View Publication

Excessive accumulation of smooth-muscle cells (SMCs) has a key role in the pathogenesis of vascular diseases. It has been assumed that SMCs derived from the outer medial layer migrate,proliferate and synthesize extracellular matrix components on the luminal side of the vessel. Although much effort has been devoted to targeting migration and proliferation of medial SMCs,there is no effective therapy that prevents occlusive vascular remodeling. We show here that in models of post-angioplasty restenosis,graft vasculopathy and hyperlipidemia-induced atherosclerosis,bone-marrow cells give rise to most of the SMCs that contribute to arterial remodeling. Notably,purified hematopoietic stem cells differentiate into SMCs in vitro and in vivo. Our findings indicate that somatic stem cells contribute to pathological remodeling of remote organs,and may provide the basis for the development of new therapeutic strategies for vascular diseases through targeting mobilization,homing,differentiation and proliferation of bone marrow-derived vascular progenitor cells. View Publication

The balance of self-renewal and differentiation in long-term repopulating hematopoietic stem cells (LT-HSC) must be strictly controlled to maintain blood homeostasis and to prevent leukemogenesis. Hematopoietic cytokines can induce differentiation in LT-HSCs; however,the molecular mechanism orchestrating this delicate balance requires further elucidation. We identified the tumor suppressor GADD45G as an instructor of LT-HSC differentiation under the control of differentiation-promoting cytokine receptor signaling. GADD45G immediately induces and accelerates differentiation in LT-HSCs and overrides the self-renewal program by specifically activating MAP3K4-mediated MAPK p38. Conversely,the absence of GADD45G enhances the self-renewal potential of LT-HSCs. Videomicroscopy-based tracking of single LT-HSCs revealed that,once GADD45G is expressed,the development of LT-HSCs into lineage-committed progeny occurred within 36 hr and uncovered a selective lineage choice with a severe reduction in megakaryocytic-erythroid cells. Here,we report an unrecognized role of GADD45G as a central molecular linker of extrinsic cytokine differentiation and lineage choice control in hematopoiesis. View Publication

The detection of primitive hematopoietic cells based on repopulation of immune-deficient mice is a powerful tool to characterize the human stem-cell compartment. Here,we identify a newly discovered human repopulating cell,distinct from previously identified repopulating cells,that initiates multilineage hematopoiesis in NOD/SCID mice. We call such cells CD34neg-SCID repopulating cells,or CD34neg-SRC. CD34neg-SRC are restricted to a Lin-CD34-CD38- population without detectable surface markers for multiple lineages and CD38 or those previously associated with stem cells (HLA-DR,Thy-1 and CD34). In contrast to CD34+ subfractions,Lin-CD34-CD38- cells have low clonogenicity in short-and long-term in vitro assays. The number of CD34neg-SRC increased in short-term suspension cultures in conditions that did not maintain SRC derived from CD34+ populations,providing independent biological evidence of their distinctiveness. The identification of this newly discovered cell demonstrates complexity of the organization of the human stem-cell compartment and has important implications for clinical applications involving stem-cell transplantation. View Publication