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

Current approaches to reprogram human somatic cells to pluripotent iPSCs utilize viral transduction of different combinations of transcription factors. These protocols are highly inefficient because only a small fraction of cells carry the appropriate number and stoichiometry of proviral insertions to initiate the reprogramming process. Here we have generated genetically homogeneous secondary" somatic cells� View Publication

The neural crest is a source to produce multipotent neural crest stem cells that have a potential to differentiate into diverse cell types. The transcription factor SOX10 is expressed through early neural crest progenitors and stem cells in vertebrates. Here we report the generation of SOX10-Nano-lantern (NL) reporter human induced pluripotent stem cells (hiPS) by using CRISPR/Cas9 systems,that are beneficial to investigate the generation and maintenance of neural crest progenitor cells. SOX10-NL positive cells are produced transiently from hiPS cells by treatment with TGFβ inhibitor SB431542 and GSK3 inhibitor CHIR99021. We found that all SOX10-NL-positive cells expressed an early neural crest marker NGFR,however SOX10-NL-positive cells purified from differentiated hiPS cells progressively attenuate their NL-expression under proliferation. We therefore attempted to maintain SOX10-NL-positive cells with additional signaling on the plane and sphere culture conditions. These SOX10-NL cells provide us to investigate mass culture with neural crest cells for stem cell research. View Publication

We have investigated the potential of stirred suspension cultures to support hematopoiesis from starting innocula of normal human bone marrow cells. Initial studies showed that the short-term maintenance of both colony-forming cell (CFC) numbers and their precursors,detected as long-term culture-initiating cells (LTC-IC),could be achieved as well in stirred suspension cultures as in static cultures. Neither of these progenitor cell populations was affected in either type of culture when porous microcarriers were added to provide an increased surface for adherent cell attachment. Supplementation of the medium with 10 ng/ml of Steel factor (SF) and 2 ng/ml of interleukin-3 (IL-3) resulted in a significant expansion of LTC-IC,CFC and total cell numbers in stirred cultures. Both the duration and ultimate magnitude of these expansions were correlated with the initial cell density and after 4 weeks the number of LTC-IC and CFC present in stirred cultures initiated with the highest starting cell concentration tested reflected average increases of 7- and 22-fold,respectively,above input values. Stirred suspension cultures offer the combined advantages of homogeneity and lack of dependence on the formation and maintenance of an adherent cell layer. Our results suggest their applicability to the development of scaled-up bioreactor systems for clinical procedures requiring the production of primitive hematopoietic cell populations. In addition,stirred suspension cultures may offer a new tool for the analysis of hematopoietic regulatory mechanisms. View Publication

The development of novel cell-based therapies requires understanding of distinct human hematopoietic stem and progenitor cell populations. We recently isolated reconstituting hematopoietic stem cells (HSCs) by lineage depletion and purification based on high aldehyde dehydrogenase activity (ALDH(hi)Lin- cells). Here,we further dissected the ALDH(hi)-Lin- population by selection for CD133,a surface molecule expressed on progenitors from hematopoietic,endothelial,and neural lineages. ALDH(hi)CD133+Lin- cells were primarily CD34+,but also included CD34-CD38-CD133+ cells,a phenotype previously associated with repopulating function. Both ALDH(hi)CD133-Lin- and ALDH(hi)CD133+Lin- cells demonstrated distinct clonogenic progenitor function in vitro,whereas only the ALDH(hi)CD133+Lin- population seeded the murine bone marrow 48 hours after transplantation. Significant human cell repopulation was observed only in NOD/SCID and NOD/SCID beta2M-null mice that received transplants of ALDH(hi)CD133+Lin- cells. Limiting dilution analysis demonstrated a 10-fold increase in the frequency of NOD/SCID repopulating cells compared with CD133+Lin- cells,suggesting that high ALDH activity further purified cells with repopulating function. Transplanted ALDH(hi)CD133+Lin- cells also maintained primitive hematopoietic phenotypes (CD34+CD38-) and demonstrated enhanced repopulating function in recipients of serial,secondary transplants. Cell selection based on ALDH activity and CD133 expression provides a novel purification of HSCs with long-term repopulating function and may be considered an alternative to CD34 cell selection for stem cell therapies. View Publication

Low dose methotrexate (LD‐MTX) remains the gold standard in rheumatoid arthritis (RA) therapy. Multiple mechanisms on a variety of immune cells contribute to the anti‐inflammatory effects of LD‐MTX. Inflammatory signaling is deeply implicated in hematopoiesis by regulating hematopoietic stem and progenitor cell (HSPC) fate decisions; raising the question of whether HSPC are also modulated by LD‐MTX. This is the first study to characterize the effects of LD‐MTX on HSPC. CD34 + HSPC were isolated from healthy donors' non‐mobilized peripheral blood. Resting and/or cycling HSPCs were treated with LD‐MTX [dose equivalent to that used in RA patients]. Flow cytometry was performed to assess HSPC viability,cell cycle,surface abundance of reduced folate carrier 1 (RFC1),proliferation,reactive oxygen species (ROS) levels,DNA double‐strand breaks,p38 activation,and CD34 + subpopulations. HSPC clonogenicity was tested in colony‐forming cell assays. Our results indicate that in cycling HSPC,membrane RFC1 is upregulated and,following LD‐MTX treatment,they accumulate more intracellular MTX than resting HSPC. In cycling HSPC,LD‐MTX inhibits HSPC expansion by promoting S‐phase cell‐cycle arrest,increases intracellular HSPC ROS levels and DNA damage,and reduces HSPC viability. Those effects involve the activation of the p38 MAPK pathway and are rescued by folinic acid. The effects of LD‐MTX are more evident in CD34 + CD38High progenitors. In non‐cycling HSPC,LD‐MTX also reduces the proliferative response while preserving their clonogenicity. In summary,HSPC uptake LD‐MTX differentially according to their cycling state. In turn,LD‐MTX results in reduced proliferation and the preservation of HSPC clonogenicity. View Publication

Targeted nucleases,including zinc-finger nucleases (ZFNs),transcription activator-like (TAL) effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9),have provided researchers with the ability to manipulate nearly any genomic sequence in human cells and model organisms. However,realizing the full potential of these genome-modifying technologies requires their safe and efficient delivery into relevant cell types. Unlike methods that rely on expression from nucleic acids,the direct delivery of nuclease proteins to cells provides rapid action and fast turnover,leading to fewer off-target effects while maintaining high rates of targeted modification. These features make nuclease protein delivery particularly well suited for precision genome engineering. Here we describe procedures for implementing protein-based genome editing in human embryonic stem cells and primary cells. Protocols for the expression,purification and delivery of ZFN proteins,which are intrinsically cell-permeable; TALEN proteins,which can be internalized via conjugation with cell-penetrating peptide moieties; and Cas9 ribonucleoprotein,whose nucleofection into cells facilitates rapid induction of multiplexed modifications,are described,along with procedures for evaluating nuclease protein activity. Once they are constructed,nuclease proteins can be expressed and purified within 6 d,and they can be used to induce genomic modifications in human cells within 2 d. View Publication

BackgroundSickle cell disease (SCD) and β-thalassemia patients with elevated gamma globin (HBG1/G2) levels exhibit mild or no symptoms. To recapitulate this natural phenomenon,the most coveted gene therapy approach is to edit the regulatory sequences of HBG1/G2 to reactivate them. By editing more than one regulatory sequence in the HBG promoter,the production of fetal hemoglobin (HbF) can be significantly increased. However,achieving this goal requires precise nucleotide conversions in hematopoietic stem and progenitor cells (HSPCs) at therapeutic efficiency,which remains a challenge.MethodsWe employed Cas9 RNP-ssODN-mediated homology-directed repair (HDR) gene editing to mimic two naturally occurring HBG promoter point mutations; -175T > C,associated with high HbF levels,and −158 C > T,a common polymorphism in the Indian population that induces HbF under erythropoietic stress,in HSPCs.ResultsAsymmetric,nontarget ssODN induced high rates of complete HDR conversions,with at least 15% of HSPCs exhibiting both the −175T > C and −158 C > T mutations. Optimized conditions and treatment with the small molecule AZD-7648 increased this rate,with up to 57% of long-term engrafting human HSPCs in NBSGW mice containing at least one beneficial mutation. Functionally,in vivo erythroblasts exhibited high levels of HbF,which was sufficient to reverse the cellular phenotype of β-thalassemia. Further support through bone marrow MSC co-culture boosted complete HDR conversion rates to exceed 80%,with minimal InDels,improved cell viability,and induced fetal hemoglobin levels similar to those of Cas9 RNP-mediated indels at BCL11A enhancer and HBG promoter.ConclusionsCas9 RNP-ssODN-based nucleotide conversion at the HBG promoter offers a promising gene therapy approach to ameliorate the phenotypes of β-thalassemia and SCD. The developed approach can simplify and broaden applications that require the cointroduction of multiple nucleotide modifications in HSPCs.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13287-024-04117-0. View Publication

Whether cytokines can modulate the fate of primitive hematopoietic progenitor cells (HPCs) through successive in vitro cell divisions has not been established. Single human marrow CD34+CD38-/lo cells in the G0 phase of cell cycle were cultured under 7 different cytokine combinations,monitored for proliferation on days 3,5,and 7,then assayed for long-term culture-initiating cell (LTC-IC) function on day 7. LTC-IC function was then retrospectively correlated with prior number of in vitro cell divisions to determine whether maintenance of LTC-IC function after in vitro cell division is dependent on cytokine exposure. In the presence of proliferation progression signals,initial cell division was independent of cytokine stimulation,suggesting that entry of primitive HPCs into the cell cycle is a stochastic property. However,kinetics of proliferation beyond day 3 and maintenance of LTC-IC function were sensitive to cytokine stimulation,such that LTC-IC underwent an initial long cell cycle,followed by more synchronized shorter cycles varying in length depending on the cytokine combination. Nonobese diabetic/severe combined immunodeficiency (NOD/SCID) transplantation studies revealed analogous results to those obtained with LTC-ICs. These data suggest that although exit from quiescence and commitment to proliferation might be stochastic,kinetics of proliferation,and possibly fate of primitive HPCs,might be modulated by extrinsic factors. View Publication

The only cure of HIV has been achieved in a small number of people who received a hematopoietic stem cell transplant (HSCT) comprising allogeneic cells carrying a rare,naturally occurring,homozygous deletion in the CCR5 gene. The rarity of the mutation and the significant morbidity and mortality of such allogeneic transplants precludes widespread adoption of this HIV cure. Here,we show the application of CRISPR/Cas9 to achieve >90% CCR5 editing in human,mobilized hematopoietic stem progenitor cells (HSPC),resulting in a transplant that undergoes normal hematopoiesis,produces CCR5 null T cells,and renders xenograft mice refractory to HIV infection. Titration studies transplanting decreasing frequencies of CCR5 edited HSPCs demonstrate that <90% CCR5 editing confers decreasing protective benefit that becomes negligible between 54% and 26%. Our study demonstrates the feasibility of using CRISPR/Cas9/RNP to produce an HSPC transplant with high frequency CCR5 editing that is refractory to HIV replication. These results raise the potential of using CRISPR/Cas9 to produce a curative autologous HSCT and bring us closer to the development of a cure for HIV infection. Subject terms: HIV infections,CRISPR-Cas9 genome editing,Retrovirus,Translational research View Publication

Both human embryonic stem cells and induced pluripotent stem cells can self-renew indefinitely in culture; however,present methods to clonally grow them are inefficient and poorly defined for genetic manipulation and therapeutic purposes. Here we develop the first chemically defined,xeno-free,feeder-free synthetic substrates to support robust self-renewal of fully dissociated human embryonic stem and induced pluripotent stem cells. Material properties including wettability,surface topography,surface chemistry and indentation elastic modulus of all polymeric substrates were quantified using high-throughput methods to develop structure-function relationships between material properties and biological performance. These analyses show that optimal human embryonic stem cell substrates are generated from monomers with high acrylate content,have a moderate wettability and employ integrin alpha(v)beta(3) and alpha(v)beta(5) engagement with adsorbed vitronectin to promote colony formation. The structure-function methodology employed herein provides a general framework for the combinatorial development of synthetic substrates for stem cell culture. View Publication

Normal murine bone marrow (BM) cells were sorted on the basis of low forward and orthogonal light scatter properties,Sca-1 expression (Sca-1+),lack of staining with a cocktail of mature hematopoietic lineage markers (Lin-),and binding of wheat germ agglutinin (WGA+). This approach allowed the reproducible isolation of a very small subpopulation (0.037% +/- 0.023% of all nucleated BM cells) that was approximately 400-fold enriched in cells capable of reconstituting both lymphoid and myeloid lineages in lethally irradiated recipients. Transplantation of 30 or 10 of these Sca-1+Lin-WGA+ cells resulted in textgreater or = to 20% donor-derived nucleated peripheral blood cells 3 months posttransplantation in 100% and 22% of the recipients,respectively. When Sca-1+Lin-WGA+ cells were cultured in serum-free medium supplemented with Steel factor,interleukin-6 (IL-6),and erythropoietin (with or without IL-3),a large increase in total cell number,including cells with an Sca-1+Lin-WGA+ phenotype was observed. Single cell cultures showed that 90% to 95% of the input cells underwent at least one division during the first 2 weeks and the remainder died. Interestingly,this proliferative response was not accompanied by a parallel increase in the number of cells with both lymphoid and myeloid repopulating potential in vivo,as quantitation of these by limiting dilution analysis showed they had decreased slightly (1.3-fold) but not significantly below the number initially present. These results demonstrate that Sca-1+Lin-WGA+ cells with long-term repopulating potential can be maintained for 2 weeks in a serum- and stroma cell-free culture,providing a simple in vitro system to study their behavior under well-defined conditions. The observed expansion of Sca-1+Lin-WGA+ cells in vitro without a concomitant increase in reconstituting cells also shows that extensive functional heterogeneity exists within populations of cells with this surface phenotype. View Publication