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

Understanding how hematopoietic stem cells (HSCs) are generated and the signals that control this process is a crucial issue for regenerative medicine applications that require in vitro production of HSC. HSCs emerge during embryonic life from an endothelial-like cell population that resides in the aorta-gonad-mesonephros (AGM) region. We show here that β-catenin is nuclear and active in few endothelial nonhematopoietic cells closely associated with the emerging hematopoietic clusters of the embryonic aorta during mouse development. Importantly,Wnt/β-catenin activity is transiently required in the AGM to generate long-term HSCs and to produce hematopoietic cells in vitro from AGM endothelial precursors. Genetic deletion of β-catenin from the embryonic endothelium stage (using VE-cadherin-Cre recombinase),but not from embryonic hematopoietic cells (using Vav1-Cre),precludes progression of mutant cells toward the hematopoietic lineage; however,these mutant cells still contribute to the adult endothelium. Together,those findings indicate that Wnt/β-catenin activity is needed for the emergence but not the maintenance of HSCs in mouse embryos. View Publication

Recent evidence suggests that protease release by neutrophils in the bone marrow may contribute to hematopoietic progenitor cell (HPC) mobilization. Matrix metalloproteinase-9 (MMP-9),neutrophil elastase (NE),and cathepsin G (CG) accumulate in the bone marrow during granulocyte colony-stimulating factor (G-CSF) treatment,where they are thought to degrade key substrates including vascular cell adhesion molecule-1 (VCAM-1) and CXCL12. To test this hypothesis,HPC mobilization was characterized in transgenic mice deficient in one or more hematopoietic proteases. Surprisingly,HPC mobilization by G-CSF was normal in MMP-9-deficient mice,NE x CG-deficient mice,or mice lacking dipeptidyl peptidase I,an enzyme required for the functional activation of many hematopoietic serine proteases. Moreover,combined inhibition of neutrophil serine proteases and metalloproteinases had no significant effect on HPC mobilization. VCAM-1 expression on bone marrow stromal cells decreased during G-CSF treatment of wild-type mice but not NE x CG-deficient mice,indicating that VCAM-1 cleavage is not required for efficient HPC mobilization. G-CSF induced a significant decrease in CXCL12 alpha protein expression in the bone marrow of Ne x CG-deficient mice,indicating that these proteases are not required to down-regulate CXCL12 expression. Collectively,these data suggest a complex model in which both protease-dependent and -independent pathways may contribute to HPC mobilization. View Publication

The low frequency of hematopoietic stem and progenitor cells (HSPCs) in human BM has precluded analysis of the direct biochemical effects elicited by cytokines in these populations,and their functional consequences. Here,single-cell phospho-specific flow cytometry was used to define the signaling networks active in 5 previously defined human HSPC subsets. This analysis revealed that the currently defined HSC compartment is composed of biochemically distinct subsets with the ability to respond rapidly and directly in vitro to a broader array of cytokines than previously appreciated,including G-CSF. The G-CSF response was physiologically relevant-driving cell-cycle entry and increased proliferation in a subset of single cells within the HSC compartment. The heterogeneity in the single-cell signaling and proliferation responses prompted subfractionation of the adult BM HSC compartment by expression of CD114 (G-CSF receptor). Xenotransplantation assays revealed that HSC activity is significantly enriched in the CD114(neg/lo) compartment,and almost completely absent in the CD114(pos) subfraction. The single-cell analyses used here can be adapted for further refinement of HSPC surface immunophenotypes,and for examining the direct regulatory effects of other factors on the homeostasis of stem and progenitor populations in normal or diseased states. View Publication

Human coronaviruses (HCoVs) enter cells via two distinct pathways: the endosomal pathway using cathepsins to activate spike protein and the cell-surface or early endosome pathway using extracellular proteases such as transmembrane protease serine 2 (TMPRSS2). We previously reported that clinical isolates of HCoV-229E preferred cell-surface TMPRSS2 to endosomal cathepsin for cell entry,and that they acquired the ability to use cathepsin L by repeated passage in cultured cells and were then able to enter cells via the endosomal pathway. Here,we show that clinical isolates of HCoV-OC43 and -HKU1 preferred the cell-surface TMRRSS2 to endosomal cathepsins for cell entry,similar to HCoV-229E. In addition,the cell-culture-adapted HCoV-OC43 lost the ability to infect and replicate in air-liquid interface cultures of human bronchial tracheal epithelial cells. These results suggest that circulating HCoVs in the field generally use cell-surface TMPRSS2 for cell entry,not endosomal cathepsins,in human airway epithelial cells. View Publication

The origins of the epithelial cells participating in the development,tissue homeostasis,and cancer of the human breast are poorly understood. However,emerging evidence suggests a role for adult tissue-specific stem cells in these processes. In a hierarchical manner,these generate the two main mammary cell lineages,producing an increasing number of cells with distinct properties. Understanding the biological characteristics of human breast stem cells and their progeny is crucial in attempts to compare the features of normal stem cells and cancer precursor cells and distinguish these from nonprecursor cells and cells from the bulk of a tumor. A historical overview of research on human breast stem cells in primary tissue and in culture reveals the progress that has been made in this area,whereas a focus on the cell-of-origin and reprogramming that occurs during neoplastic conversion provides insight into the enigmatic way in which human breast cancers are skewed toward the luminal epithelial lineage. View Publication

Differentiation of pluripotent cells into endoderm-related cell types initially requires in vitro gastrulation into the definitive endoderm (DE). Most differentiation protocols are initiated from colonies of pluripotent cells complicating their adaption due to insufficiently defined starting conditions. The protocol described here was initiated from a defined cell number of dispersed single cells and tested on three different human embryonic stem cell lines and one human induced pluripotent stem cell line. Combined activation of ActivinA/Nodal signaling and GSK3 inhibition for the first 24 h,followed by ActivinA/Nodal signaling efficiently induced the DE state. Activation of ActivinA/Nodal signaling alone was not effective. Efficient GSK3 inhibition allowed the reduction of the ActivinA concentration during the entire protocol. A feeder-independent cultivation of pluripotent cells was preferred to achieve the high efficiency and robustness since feeder cells hindered the differentiation process. Additionally,inhibition of the phosphatidylinositol 3-kinase (PI3K) signaling pathway was not required,nonetheless yielding high cell numbers efficiently committed toward the DE. Finally,the endoderm generated could be differentiated further into PDX1-positive pan-pancreatic cells and NGN3-positive endocrine progenitors. Thus,this efficient and robust DE differentiation protocol is a step forward toward better reproducibility due to the well-defined conditions based on dispersed single cells from feeder-free-cultivated human pluripotent cells. View Publication

SummaryStudying the cis-regulatory elements (CREs) of genes in Th17 cells during autoimmune disease progression,such as experimental autoimmune encephalomyelitis (EAE),is often limited by the availability of gene-edited mice. Here,we present a protocol for CRISPR-mediated deletion of a CRE in murine Th17 cells for in vivo assessment of effector function in EAE. We describe steps for dual U6gRNA construction,preparation of retroviruses,viral delivery,and Th17 differentiation. We then detail procedures for in vivo functionality analysis.For complete details on the use and execution of this protocol,please refer to Zhong et al.1,2 Graphical abstract Highlights•Steps for designing and cloning dual U6gRNA cassettes to delete a specific CRE•Instructions for optimized retrovirus production and transduction into CD4+ T cells•Guidance on Th17 differentiation and confirmation of CRE deletion in cultured T cells•Procedures for adoptive transfer of CRISPR-edited Th17 cells to assess in vivo function Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics. Studying the cis-regulatory elements (CREs) of genes in Th17 cells during autoimmune disease progression,such as experimental autoimmune encephalomyelitis (EAE),is often limited by the availability of gene-edited mice. Here,we present a protocol for CRISPR-mediated deletion of a CRE in murine Th17 cells for in vivo assessment of effector function in EAE. We describe steps for dual U6gRNA construction,preparation of retroviruses,viral delivery,and Th17 differentiation. We then detail procedures for in vivo functionality analysis. View Publication

Progress toward finding a cure for muscle diseases has been slow because of the absence of relevant cellular models and the lack of a reliable source of muscle progenitors for biomedical investigation. Here we report an optimized serum-free differentiation protocol to efficiently produce striated,millimeter-long muscle fibers together with satellite-like cells from human pluripotent stem cells (hPSCs) in vitro. By mimicking key signaling events leading to muscle formation in the embryo,in particular the dual modulation of Wnt and bone morphogenetic protein (BMP) pathway signaling,this directed differentiation protocol avoids the requirement for genetic modifications or cell sorting. Robust myogenesis can be achieved in vitro within 1 month by personnel experienced in hPSC culture. The differentiating culture can be subcultured to produce large amounts of myogenic progenitors amenable to numerous downstream applications. Beyond the study of myogenesis,this differentiation method offers an attractive platform for the development of relevant in vitro models of muscle dystrophies and drug screening strategies,as well as providing a source of cells for tissue engineering and cell therapy approaches. View Publication

High-titer,HIV-1-based lentiviral vector particles were found to transduce cytokine-mobilized rhesus macaque CD34(+) cells and clonogenic progenitors very poorly (textless 1%),reflecting the postentry restriction in rhesus cells to HIV infection. To overcome this barrier,we developed a simian immunodeficiency virus (SIV)-based vector system. A single exposure to a low concentration of amphotropic pseudotyped SIV vector particles encoding the green fluorescent protein (GFP) resulted in gene transfer into 68% +/- 1% of rhesus bulk CD34(+) cells and 75% +/- 1% of clonogenic progenitors. Polymerase chain reaction (PCR) analysis of DNA from individual hematopoietic colonies confirmed these relative transduction efficiencies. To evaluate SIV vector-mediated stem cell gene transfer in vivo,3 rhesus macaques underwent transplantation with transduced,autologous cytokine-mobilized peripheral blood CD34(+) cells following myeloablative conditioning. Hematopoietic reconstitution was rapid,and an average of 18% +/- 8% and 15% +/- 7% GFP-positive granulocytes and monocytes,respectively,were observed 4 to 6 months after transplantation,consistent with the average vector copy number of 0.19 +/- 0.05 in peripheral blood leukocytes as determined by real-time PCR. Vector insertion site analysis demonstrated polyclonal reconstitution with vector-containing cells. SIV vectors appear promising for evaluating gene therapy approaches in nonhuman primate models. View Publication

p18 INK4 C (CDKN2C,encoded by p18 INK4c or Cdkn2c ) is an early G1-phase cyclin-dependent kinase inhibitor protein. Previous studies demonstrated enhanced self-renewal capacity of hematopoietic stem cells (HSCs) in p18 −/− mice compared to wild-type (WT) mice. Given the critical role of bone marrow niche cells-particularly mesenchymal stromal cells (MSCs)-in hematopoiesis,this study investigated the functional alterations of p18 −/− MSCs and their impact on hematopoietic support. Bone marrow derived MSCs were isolated from p18 −/− and WT mice. Their proliferation and differentiation capacities were assessed,followed by evaluation of hematopoietic support using cobblestone area-forming cell assay and long-term culture-initiating cell assay. RNA sequencing was performed to analyze the transcriptional profile of p18 −/− MSCs,with a focus on differentially expressed genes (DEGs). Key pathways associated with hematopoietic support were identified using Ingenuity Pathway Analysis. A candidate protein was quantified by ELISA,and its functional role in hematopoietic support was validated via a modified coculture system. p18 −/− MSCs displayed an increased proliferation rate,preferential differentiation toward osteogenesis over adipogenesis,and enhanced hematopoietic support. RNA sequencing analysis identified 137 DEGs,with secreted phosphoprotein 1 ( Spp1,encoding osteopontin,Opn) being significantly upregulated in p18 −/− MSCs. Elevated Opn levels were confirmed in both bone marrow and MSC-conditioned media from p18 −/− mice. Functional validation further demonstrated that Opn enhanced the hematopoietic supportive capacity of MSCs in vitro. p18 deficiency promotes osteogenic differentiation and enhances the hematopoietic supportive function of MSCs,likely mediated by Opn upregulation. These findings suggest a potential therapeutic strategy for improving bone regeneration and HSC expansion. The online version contains supplementary material available at 10.1186/s13287-025-04402-6. View Publication