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

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

Human pluripotent stem cells (hPSCs) and their differentiated derivatives represent valuable tools for studying development,modeling diseases,and advancing cell therapy. Recent improvements in genome engineering allow for precise modifications of hPSCs,further enhancing their utility in basic and translational research. Here we describe a Recombinase-Mediated Cassette Exchange (RMCE) platform in hPSCs that allows for the highly efficient,rapid,and specific integration of transgenes. The RCME-mediated DNA integration process is nearly 100% efficient,without negatively affecting the pluripotency or karyotypic stability of hPSCs. Taking advantage of this convenient system,we first established a dual inducible expression system based on the Tet-On and Cumate-On systems,allowing for the inducible expression of two transgenes independently. Secondly,we incorporated a Tet-on inducible system,driving the expression of three genes simultaneously. However,two genes also contain independent degron sequences,allowing for precise control over the expression of each gene individually. We demonstrated the utility of these systems in hPSCs,as well as their functionality after differentiation into cells that were representative of the three germ layers. Lastly,we used the triple inducible system to investigate the lineage commitment induced by the pancreatic transcription factors NKX6.1 and PDX1. We found that controlled dual expression,but not individual expression,biases hPSC embryoid body differentiation towards the pancreatic lineage by inducing the expression of the NeuroD program. In sum,we describe a novel genetic engineering platform that allows for the efficient and fast integration of any desired transgene(s) in hPSCs using RMCE. We anticipate that the ability to modulate the expression of three transgenes simultaneously will further accelerate discoveries using stem cell technology. View Publication

Hematopoietic stem and progenitor cells (HSPCs) are critical for the treatment of blood diseases in clinic. However,the limited source of HSPCs severely hinders their clinical application. In the embryo,hematopoietic stem cells (HSCs) arise from hemogenic endothelial (HE) cells lining the major arteries in vivo. In this work,by engineering vascular niche endothelial cells (VN-ECs),we generated functional HSPCs in vitro from ECs at various sites,including the aorta-gonad-mesonephros (AGM) region and the placenta. Firstly,we converted mouse embryonic HE cells from the AGM region (aHE) into induced HSPCs (iHSPCs),which have the abilities for multilineage differentiation and self-renewal. Mechanistically,we found that VN-ECs can promote the generation of iHSPCs via secretion of CX3CL1 and IL1A. Next,through VN-EC co-culture,we showed that placental HE (pHE) cells,a type of extra-embryonic HE cells,were successfully converted into iHSPCs (pHE-iHSPCs),which have multilineage differentiation capacity,but exhibit limited self-renewal ability. Furthermore,comparative transcriptome analysis of aHE-iHSPCs and pHE-iHSPCs showed that aHE-iHSPCs highly expressed HSC-specific and self-renewal-related genes. Moreover,experimental validation showed that retinoic acid (RA) treatment promoted the transformation of pHE cells into iHSPCs that have self-renewal ability. Collectively,our results suggested that pHE cells possess the potential to transform into self-renewing iHSPCs through RA treatment,which will facilitate the clinical application of placental endothelial cells in hematopoietic cell generation. Subject terms: Haematopoietic stem cells,Haematopoietic stem cells View Publication

AIMS The aim of this study was to improve a method that induce cartilage differentiation of human embryoid stem cells (hESCs) in vitro,and test the effect of in vivo environments on the further maturation of hESCs derived cells. MAIN METHODS Embryoid bodies (EBs) formed from hESCs,with serum-free KSR-based medium and mesodermal specification related factors,CHIR,and Noggin for first 8days. Then cells were digested and cultured as micropellets in serum-free KSR-based chondrogenic medium that was supplemented with PDGF-BB,TGF β3,BMP4 in sequence for 24days. The morphology,FACS,histological staining as well as the expression of chondrogenic specific genes were detected in each stage,and further in vivo experiments,cell injections and tissue transplantations,further verified the formation of chondrocytes. KEY FINDINGS We were able to obtain chondrocyte/cartilage from hESCs using serum-free KSR-based conditioned medium. qPCR analysis showed that expression of the chondroprogenitor genes and the chondrocyte/cartilage matrix genes. Morphology analysis demonstrated we got PG+COL2+COL1-particles. It indicated we obtained hyaline cartilage-like particles. 32-Day differential cells were injected subcutaneous. Staining results showed grafts developed further mature in vivo. But when transplanted in subrenal capsule,their effect was not good as in subcutaneous. Microenvironment might affect the cartilage formation. SIGNIFICANCE The results of this study provide an absolute serum-free and efficient approach for generation of hESC-derived chondrocytes,and cells will become further maturation in vivo. It provides evidence and technology for the hypothesis that hESCs may be a promising therapy for the treatment of cartilage disease. 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

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

Due to widespread applications of human embryonic stem (hES) cells,it is essential to establish effective protocols for cryopreservation and subsequent culture of hES cells to improve cell recovery. We have developed a new protocol for cryopreservation of dissociated hES cells and subsequent culture. We examined the effects of new formula of freezing solution containing 7.5% dimethylsulfoxide (DMSO) (v/v %) and 2.5% polyethylene glycol (PEG) (w/v %) on cell survival and recovery of hES cells after cryopreservation,and further investigated the role of the combination of Rho-associated kinase (ROCK) inhibitor and p53 inhibitor on cell recovery during the subsequent culture. Compared with the conventional slow-freezing method which uses 10% DMSO as a freezing solution and then cultured in the presence of ROCK inhibitor at the first day of culture,we found out that hES cell recovery was significantly enhanced by around 30 % (P textless 0.05) by the new freezing solution. Moreover,at the first day of post-thaw culture,the presence of 10 microM ROCK inhibitor (Y-27632) and 1 microM pifithrin-mu together further significantly improved cell recovery by around 20% (P textless 0.05) either for feeder-dependent or feeder-independent culture. hES cells remained their undifferentiated status after using this novel protocol for cryopreservation and subsequent culture. Furthermore,this protocol is a scalable cryopreservation method for handling large quantities of hES cells. View Publication

Prolonged in vitro culture of human embryonic stem (hES) cells can result in chromosomal abnormalities believed to confer a selective advantage. This potential occurrence has crucial implications for the appropriate use of hES cells for research and therapeutic purposes. In view of this,time-point karyotypic evaluation to assess genetic stability is recommended as a necessary control test to be carried out during extensive 'passaging'. Standard techniques currently used for the cytogenetic assessment of ES cells include G-banding and/or Fluorescence in situ Hybridization (FISH)-based protocols for karyotype analysis,including M-FISH and SKY. Critical for both banding and FISH techniques are the number and quality of metaphase spreads available for analysis at the microscope. Protocols for chromosome preparation from hES and human induced pluripotent stem (hiPS) cells published so far appear to differ considerably from one laboratory to another. Here we present an optimized technique,in which both the number and the quality of chromosome metaphase spreads were substantially improved when compared to current standard techniques for chromosome preparations. We believe our protocol represents a significant advancement in this line of work,and has the required attributes of simplicity and consistency to be widely accepted as a reference method for high quality,fast chromosomal analysis of human ES and iPS cells. View Publication

SummaryHere,we present a protocol to generate craniofacial cartilage organoids from human stem cells via neural crest stem cells (NCSCs). We describe steps for inducing human embryonic stem cells (hESCs) or induced pluripotent stem cells (iPSCs) to form NCSCs using sequential treatments of small molecules and growth factors and isolating NCSCs by magnetic bead sorting. We then detail procedures for defining conditions where NCSCs migrate together and self-organize into craniofacial cartilage organoids. Recapitulating craniofacial chondrogenesis will facilitate craniofacial reconstruction and disease modeling.For complete details on the use and execution of this protocol,please refer to Foltz et al.1 Graphical abstract Highlights•Protocol for inducing hESCs or iPSCs to form neural crest stem cells (NCSCs)•Steps for differentiating NCSCs into craniofacial cartilage organoids•Instructions for preparing appropriate media and conditions for differentiation•Guidance for assessing changes in cell and organoid morphology during differentiation Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics. Here,we present a protocol to generate craniofacial cartilage organoids from human stem cells via neural crest stem cells (NCSCs). We describe steps for inducing human embryonic stem cells (hESCs) or induced pluripotent stem cells (iPSCs) to form NCSCs using sequential treatments of small molecules and growth factors and isolating NCSCs by magnetic bead sorting. We then detail procedures for defining conditions where NCSCs migrate together and self-organize into craniofacial cartilage organoids. Recapitulating craniofacial chondrogenesis will facilitate craniofacial reconstruction and disease modeling. View Publication

We have developed a synthetic polymer interface for the long-term self-renewal of human embryonic stem cells (hESCs) in defined media. We successfully cultured hESCs on hydrogel interfaces of aminopropylmethacrylamide (APMAAm) for over 20 passages in chemically-defined mTeSR™1 media and demonstrated pluripotency of multiple hESC lines with immunostaining and quantitative RT-PCR studies. Results for hESC proliferation and pluripotency markers were both qualitatively and quantitatively similar to cells cultured on Matrigel™-coated substrates. Mechanistically,it was resolved that bovine serum albumin (BSA) in the mTeSR™1 media was critical for cell adhesion on APMAAm hydrogel interfaces. This study uniquely identified a robust long-term culture surface for the self-renewal of hESCs without the use of biologic coatings (e.g.,peptides,proteins,or Matrigel™) in completely chemically-defined media that employed practical culturing techniques amenable to clinical-scale cell expansion. View Publication