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

To test the hypothesis that aging has negative effects on stem-cell homing and engraftment,young or old C57BL/6 bone marrow (BM) cells were injected,using a limiting-dilution,competitive transplantation method,into old or young Ly5 congenic mice. Numbers of hematopoietic stem cells (HSCs) and progenitor cells (HPCs) recovered from BM or spleen were measured and compared with the numbers initially transplanted. Although the frequency of marrow competitive repopulation units (CRUs) increased approximately 2-fold from 2 months to 2 years of age,the BM homing efficiency of old CRUs was approximately 3-fold lower than that of young CRUs. Surprisingly,the overall size of individual stem-cell clones generated in recipients receiving a single CRU was not affected by donor age. However,the increased ages of HSC donors and HSC transplant recipients caused marked skewing of the pattern of engraftment toward the myeloid lineage,indicating that HSC-intrinsic and HSC-extrinsic (microenvironmental) age-related changes favor myelopoiesis. This correlated with changes after transplantation in the rate of recovery of circulating leukocytes,erythrocytes,and platelets. Recovery of the latter was especially blunted in aged recipients. Collectively,these findings may have implications for clinical HSC transplantation in which older persons increasingly serve as donors for elderly patients. View Publication

Stem cell leukemia/T cell acute leukemia 1 (SCL/TAL1) plays a key role in the development of murine primitive hematopoiesis but its functions in adult definitive hematopoiesis are still unclear. Using lentiviral delivery of TAL1-directed shRNA in human hematopoietic cells,we show that decreased expression of TAL1 induced major disorders at different levels of adult hematopoietic cell development. Erythroid and myeloid cell production in cultures was dramatically decreased in TAL1-directed shRNA-expressing cells,whereas lymphoid B-cell development was normal. These results confirm the role of TAL1 in the erythroid compartment and show TLA1's implication in the function of myeloid committed progenitors. Moreover,long-term cultures and transplantation of TAL1-directed shRNA-expressing CD34+ cells into irradiated nonobese diabetic-severe combined immunodeficient (NOD-SCID) mice led to dramatically low levels of human cells of all lineages including the B-lymphoid lineage,strongly suggesting that TAL1 has a role in the early commitment of hematopoietic stem cells (HSCs) in humans. Cultures and transplantation experiments performed with mouse Sca1+ cells gave identical results. Altogether,these observations definitively show that TAL1 participates in the regulation of hematopoiesis from HSCs to myeloid progenitors,and pinpoint TAL1 as a master protein of human and murine adult hematopoiesis. 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

Air-liquid interface (ALI) culture of nasal epithelial cells is a valuable tool in the diagnosis and research of primary ciliary dyskinesia (PCD). Ex vivo samples often display secondary dyskinesia from cell damage during sampling,infection or inflammation confounding PCD diagnostic results. ALI culture enables regeneration of healthy cilia facilitating differentiation of primary from secondary ciliary dyskinesia. We describe a revised ALI culture method adopted from April 2018 across three collaborating PCD diagnostic sites,including current University Hospital Southampton COVID-19 risk mitigation measures,and present results. Two hundred and forty nasal epithelial cell samples were seeded for ALI culture and 199 (82.9{\%}) were ciliated. Fifty-four of 83 (63.9{\%}) ex vivo samples which were originally equivocal or insufficient provided diagnostic information following in vitro culture. Surplus basal epithelial cells from 181 nasal brushing samples were frozen in liquid nitrogen; 39 samples were ALI-cultured after cryostorage and all ciliated. The ciliary beat patterns of ex vivo samples (by high-speed video microscopy) were recapitulated,scanning electron microscopy demonstrated excellent ciliation,and cilia could be immuno-fluorescently labelled (anti-alpha-tubulin and anti-RSPH4a) in representative cases that were ALI-cultured after cryostorage. In summary,our ALI culture protocol provides high ciliation rates across three centres,minimising patient recall for repeat brushing biopsies and improving diagnostic certainty. Cryostorage of surplus diagnostic samples was successful,facilitating PCD research. View Publication

To search for new indicators of self-renewing hematopoietic stem cells (HSCs),highly purified populations were isolated from adult mouse marrow,micromanipulated into a specially designed microscopic array,and cultured for 4 days in 300 ng/ml Steel factor,20 ng/ml IL-11,and 1 ng/ml flt3-ligand. During this period,each cell and its progeny were imaged at 3-min intervals by using digital time-lapse photography. Individual clones were then harvested and assayed for HSCs in mice by using a 4-month multilineage repopulation endpoint (textgreater1% contribution to lymphoid and myeloid lineages). In a first experiment,6 of 14 initial cells (43%) and 17 of 61 clones (28%) had HSC activity,demonstrating that HSC self-renewal divisions had occurred in vitro. Characteristics associated with HSC activity included longer cell-cycle times and the absence of uropodia on a majority of cells within the clone during the final 12 h of culture. Combining these criteria maximized the distinction of clones with HSC activity from those without and identified a subset of 27 of the 61 clones. These 27 clones included all 17 clones that had HSC activity; a detection efficiency of 63% (2.26 times more frequently than in the original group). The utility of these characteristics for discriminating HSC-containing clones was confirmed in two independent experiments where all HSC-containing clones were identified at a similar 2- to 3-fold-greater efficiency. These studies illustrate the potential of this monitoring system to detect new features of proliferating HSCs that are predictive of self-renewal divisions. 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

The maintenance of a basal immunoinflammatory signature in hematopoietic stem/progenitor cells (HSPCs) constitutes a fundamental regulatory axis governing hematopoietic competence and immune effector generation. While epigenetic repressors constrain this inflammatory phenotype,the molecular amplifiers that preserve this critical state remain undefined. Through integrated single-cell transcriptomic/epigenomic profiling and functional interrogation,we identify Setd2-mediated H3K36me3 as an indispensable epigenetic amplifier sustaining baseline inflammation in murine HSPCs. Setd2 ablation specifically eliminated interferon (IFN)-enriched HSPC subpopulations and attenuated inflammatory signaling cascades. Functionally,Setd2-deficient HSPCs exhibited impaired IFNγ responsiveness,compromised B-lymphopoiesis,and diminished reconstitution capacity due to Lin−c-Kit+Sca1high cell depletion. Paradoxically,Setd2 loss conferred resistance to IFNγ-induced HSPCs exhaustion,which may contribute to the maintenance of Setd2-deficient HSPCs in our myelodysplastic syndrome (MDS) model under the inflammatory milieu. Mechanistically,Setd2 sustained chromatin accessibility and enhancer (H3K27ac) activity at inflammatory gene loci. This work delineates a critical link between Setd2-mediated chromatin regulation,baseline inflammation,HSPC function,and immune competence,providing insights into inflammatory dysregulation in hematopoietic malignancies like MDS. View Publication

Epstein-Barr virus (EBV) persistently infects more than 90% of the human population,causing infectious mononucleosis,susceptibility to autoimmune diseases and multiple malignancies of epithelial or B cell-origin. EBV infects epithelial cells and B cells through interaction between viral glycoproteins and different host receptors,but it has remained unknown whether a common receptor mediates infection of its two major host cell targets. Here,we establish R9AP as a crucial EBV receptor for entry into epithelial and B cells. R9AP silencing or knockout,R9AP-derived peptide and R9AP monoclonal antibody each significantly inhibit,whereas R9AP overexpression promotes,EBV uptake into both cell types. R9AP binds directly to the EBV glycoprotein gH/gL complex to initiate gH/gL-gB-mediated membrane fusion. Notably,the interaction of R9AP with gH/gL is inhibited by the highly competitive gH/gL-neutralizing antibody AMMO1,which blocks EBV epithelial and B cell entry. Moreover,R9AP mediates viral and cellular membrane fusion in cooperation with EBV gp42-human leukocyte antigen class II or gH/gL-EPHA2 complexes in B cells or epithelial cells,respectively. We propose R9AP as the crucial common receptor of B cells and epithelial cells and a potential prophylactic and vaccine target for EBV. View Publication

Pluripotent or multipotent cell-based therapeutics are vital for skeletal reconstruction in non-healing critical-sized defects since the local endogenous progenitor cells are not often adequate to restore tissue continuity or function. However,currently available cell-based regenerative strategies are hindered by numerous obstacles including inadequate cell availability,painful and invasive cell-harvesting procedures,and tumorigenesis. Previously,we established a novel platform technology for inducing a quiescent stem cell-like stage using only a single extracellular proteoglycan,fibromodulin (FMOD),circumventing gene transduction. In this study,we further purified and significantly increased the reprogramming rate of the yield multipotent FMOD reprogrammed (FReP) cells. We also exposed the 'molecular blueprint' of FReP cell osteogenic differentiation by gene profiling. Radiographic analysis showed that implantation of FReP cells into a critical-sized SCID mouse calvarial defect,contributed to the robust osteogenic capability of FReP cells in a challenging clinically relevant traumatic scenario in vivo. The persistence,engraftment,and osteogenesis of transplanted FReP cells without tumorigenesis in vivo were confirmed by histological and immunohistochemical staining. Taken together,we have provided an extended potency,safety,and molecular profile of FReP cell-based bone regeneration. Therefore,FReP cells present a high potential for cellular and gene therapy products for bone regeneration. View Publication

Stem cells hold great promise for therapies aimed at regenerating damaged tissue,drug screening and studying in vitro models of human disease. However,many challenges remain before these applications can become a reality. One such challenge is developing chemically defined and scalable culture conditions for derivation and expansion of clinically viable human pluripotent stem cells,as well as controlling their differentiation with high specificity. Interaction of stem cells with their extracellular microenvironment plays an important role in determining their differentiation commitment and functions. Regenerative medicine approaches integrating cell-matrix and cell-cell interactions,and soluble factors could lead to development of robust microenvironments to control various cellular responses. Indeed,several of these recent developments have provided significant insight into the design of microenvironments that can elicit the targeted cellular response. In this article,we will focus on some of these developments with an emphasis on matrix-mediated expansion of human pluripotent stem cells while maintaining their pluripotency. We will also discuss the role of matrix-based cues and cell-cell interactions in the form of soluble signals in directing stem cell differentiation into musculoskeletal lineages. View Publication

The potential for human disease treatment using human pluripotent stem cells,including embryonic stem cells and induced pluripotent stem cells (iPSCs),also carries the risk of added genomic instability. Genomic instability is most often linked to DNA repair deficiencies,which indicates that screening/characterization of possible repair deficiencies in pluripotent human stem cells should be a necessary step prior to their clinical and research use. In this study,a comparison of DNA repair pathways in pluripotent cells,as compared to those in non-pluripotent cells,demonstrated that DNA repair capacities of pluripotent cell lines were more heterogeneous than those of differentiated lines examined and were generally greater. Although pluripotent cells had high DNA repair capacities for nucleotide excision repair,we show that ultraviolet radiation at low fluxes induced an apoptotic response in these cells,while differentiated cells lacked response to this stimulus,and note that pluripotent cells had a similar apoptotic response to alkylating agent damage. This sensitivity of pluripotent cells to damage is notable since viable pluripotent cells exhibit less ultraviolet light-induced DNA damage than do differentiated cells that receive the same flux. In addition,the importance of screening pluripotent cells for DNA repair defects was highlighted by an iPSC line that demonstrated a normal spectral karyotype,but showed both microsatellite instability and reduced DNA repair capacities in three out of four DNA repair pathways examined. Together,these results demonstrate a need to evaluate DNA repair capacities in pluripotent cell lines,in order to characterize their genomic stability,prior to their pre-clinical and clinical use. View Publication

miRNA,short non-coding RNA,are rapidly emerging as important regulators in cell homeostasis,as well as potential players in cellular degeneration. The latter has led to interest in them as both biomarkers and as potential therapeutics. Retinal ganglion cells (RGC),whose axons connect the eye to the brain,are central nervous system cells of great interest,yet their study is largely restricted to animals due to the difficulty in obtaining healthy human RGC. Using a CRISPR/Cas9-based reporter embryonic stem cell line,human RGC were generated and their miRNA profile characterized using NanoString miRNA assays. We identified a variety of retinal specific miRNA upregulated in ESC-derived RGC,with half of the most abundant miRNA also detectable in purified rat RGC. Several miRNA were however identified to be unique to RGC from human. The findings show which miRNA are abundant in RGC and the limited congruence with animal derived RGC. These data could be used to understand miRNA’s role in RGC function,as well as potential biomarkers or therapies in retinal diseases involving RGC degeneration. View Publication