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

Human pluripotent stem cells (hPSCs) have the potential for unlimited expansion and differentiation into cell types of all three germ layers. Cryopreservation is a key process for successful application of hPSCs. However,the current conventional method leads to poor recovery of hPSCs after thawing. Here,we demonstrate a highly efficient recovery method for hPSC cryopreservation by slow freezing and single-cell dissociation. After confirming hPSC survivability after freeze-thawing,we found that hPSCs that were freeze-thawed as colonies showed markedly decreased survival,whereas freeze-thawed single hPSCs retained the majority of their viability. These observations indicated that hPSCs should be cryopreserved as single cells. Freeze-thawed single hPSCs efficiently adhered and survived in the absence of a ROCK inhibitor by optimization of the seeding density. The high recovery rate enabled conventional colony passaging for subculture within 3 days post-thawing. The improved method was also adapted to a xeno-free culture system. Moreover,the cell recovery postcryopreservation was highly supported by coating culture surfaces with human laminin-521 that promotes adhesion of dissociated single hPSCs. This simplified but highly efficient cryopreservation method allows easy handling of cells and bulk storage of high-quality hPSCs. View Publication

Interleukin-17A (IL-17A) and IL-17F are 2 of several cytokines produced by T helper 17 cells (Th17),which are able to indirectly induce the recruitment of neutrophils. Recently,human Th17 cells have been phenotypically characterized and shown to express discrete chemokine receptors,including CCR2 and CCR6. Herein,we show that highly purified neutrophils cultured with interferon-gamma plus lipopolysaccharide produce the CCL2 and CCL20 chemokines,the known ligands of CCR2 and CCR6,respectively. Accordingly,supernatants from activated neutrophils induced chemotaxis of Th17 cells,which was greatly suppressed by anti-CCL20 and anti-CCL2 antibodies. We also discovered that activated Th17 cells could directly chemoattract neutrophils via the release of biologically active CXCL8. Consistent with this reciprocal recruitment,neutrophils and Th17 cells were found in gut tissue from Crohn disease and synovial fluid from rheumatoid arthritis patients. Finally,we report that,although human Th17 cells can directly interact with freshly isolated or preactivated neutrophils via granulocyte-macrophage colony-stimulating factor,tumor necrosis factor-alpha,and interferon-gamma release,these latter cells cannot be activated by IL-17A and IL-17F,because of their lack of IL-17RC expression. Collectively,our results reveal a novel chemokine-dependent reciprocal cross-talk between neutrophils and Th17 cells,which may represent a useful target for the treatment of chronic inflammatory diseases. View Publication

It is often predicted that stem cells divide asymmetrically,creating a daughter cell that maintains the stem-cell capacity,and 1 daughter cell committed to differentiation. While asymmetric stem-cell divisions have been proven to occur in model organisms (eg,in Drosophila),it remains illusive whether primitive hematopoietic cells in mammals actually can divide asymmetrically. In our experiments we have challenged this question and analyzed the developmental capacity of separated offspring of primitive human hematopoietic cells at a single-cell level. We show for the first time that the vast majority of the most primitive,in vitro-detectable human hematopoietic cells give rise to daughter cells adopting different cell fates; 1 inheriting the developmental capacity of the mother cell,and 1 becoming more specified. In contrast,approximately half of the committed progenitor cells studied gave rise to daughter cells,both of which adopted the cell fate of their mother. Although our data are compatible with the model of asymmetric cell division,other mechanisms of cell fate specification are discussed. In addition,we describe a novel human hematopoietic progenitor cell that has the capacity to form natural killer (NK) cells as well as macrophages,but not cells of other myeloid lineages. View Publication

Genetic diseases of blood cells are prime candidates for treatment through ex vivo gene editing of CD34+ hematopoietic stem/progenitor cells (HSPCs),and a variety of technologies have been proposed to treat these disorders. Sickle cell disease (SCD) is a recessive genetic disorder caused by a single-nucleotide polymorphism in the $\beta$-globin gene (HBB). Sickle hemoglobin damages erythrocytes,causing vasoocclusion,severe pain,progressive organ damage,and premature death. We optimize design and delivery parameters of a ribonucleoprotein (RNP) complex comprising Cas9 protein and unmodified single guide RNA,together with a single-stranded DNA oligonucleotide donor (ssODN),to enable efficient replacement of the SCD mutation in human HSPCs. Corrected HSPCs from SCD patients produced less sickle hemoglobin RNA and protein and correspondingly increased wild-type hemoglobin when differentiated into erythroblasts. When engrafted into immunocompromised mice,ex vivo treated human HSPCs maintain SCD gene edits throughout 16 weeks at a level likely to have clinical benefit. These results demonstrate that an accessible approach combining Cas9 RNP with an ssODN can mediate efficient HSPC genome editing,enables investigator-led exploration of gene editing reagents in primary hematopoietic stem cells,and suggests a path toward the development of new gene editing treatments for SCD and other hematopoietic diseases. View Publication

There is need in the pharmaceutical and chemical industries for high-throughput human cell-based assays for identifying hazardous chemicals,thereby reducing the overall reliance on animal studies for predicting the risk of toxic responses in humans. Despite instances of human-specific teratogens such as thalidomide,the use of human cell-teratogenicity assays has just started to be explored. Herein,a human pluripotent stem cell test (hPST) for identifying teratogens is described,benchmarking the in vitro findings to traditional preclinical toxicology teratogenicity studies and when available to teratogenic outcomes in humans. The hPST method employs a 3-day monolayer directed differentiation of human embryonic stem cells. The teratogenic risk of a compound is gauged by measuring the reduction in nuclear translocation of the transcription factor SOX17 in mesendodermal cells. Decreased nuclear SOX17 in the hPST model was strongly correlated with in vivo teratogenicity. Specifically,71 drug-like compounds with known in vivo effects,including thalidomide,were examined in the hPST. A threshold of 5μM demonstrated 94% accuracy (97% sensitivity and 92% specificity). Furthermore,15 environmental toxicants with physicochemical properties distinct from small molecule pharmaceutical agents were examined and a similarly strong concordance with teratogenicity outcomes from in vivo studies was observed. Finally,to assess the suitability of the hPST for high-throughput screens,a small library of 300 kinase inhibitors was tested,demonstrating the hPST platform's utility for interrogating teratogenic mechanisms and drug safety prediction. Thus,the hPST assay is a robust predictor of teratogenicity and appears to be an improvement over existing in vitro models. View Publication

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

The use of human pluripotent stem cells,including embryonic and induced pluripotent stem cells,in therapeutic applications will require the development of robust,scalable culture technologies for undifferentiated cells. Advances made in large-scale cultures of other mammalian cells will facilitate expansion of undifferentiated human embryonic stem cells (hESCs),but challenges specific to hESCs will also have to be addressed,including development of defined,humanized culture media and substrates,monitoring spontaneous differentiation and heterogeneity in the cultures,and maintaining karyotypic integrity in the cells. This review will describe our current understanding of environmental factors that regulate hESC self-renewal and efforts to provide these cues in various scalable bioreactor culture systems. View Publication

Engineered neural stem cells (NSCs) are a promising approach to treating glioblastoma (GBM). The ideal NSC drug carrier for clinical use should be easily isolated and autologous to avoid immune rejection. We transdifferentiated (TD) human fibroblasts into tumor-homing early-stage induced NSCs (h-iNSC(TE)),engineered them to express optical reporters and different therapeutic gene products,and assessed the tumor-homing migration and therapeutic efficacy of cytotoxic h-iNSC(TE) in patient-derived GBM models of surgical and nonsurgical disease. Molecular and functional analysis revealed that our single-factor SOX2 TD strategy converted human skin fibroblasts into h-iNSC(TE) that were nestin(+) and expressed pathways associated with tumor-homing migration in 4 days. Time-lapse motion analysis showed that h-iNSC(TE) rapidly migrated to human GBM cells and penetrated human GBM spheroids,a process inhibited by blockade of CXCR4. Serial imaging showed that h-iNSC(TE) delivery of the proapoptotic agent tumor necrosis factor-α-related apoptosis-inducing ligand (TRAIL) reduced the size of solid human GBM xenografts 250-fold in 3 weeks and prolonged median survival from 22 to 49 days. Additionally,h-iNSC(TE) thymidine kinase/ganciclovir enzyme/prodrug therapy (h-iNSC(TE)-TK) reduced the size of patient-derived GBM xenografts 20-fold and extended survival from 32 to 62 days. Mimicking clinical NSC therapy,h-iNSC(TE)-TK therapy delivered into the postoperative surgical resection cavity delayed the regrowth of residual GBMs threefold and prolonged survival from 46 to 60 days. These results suggest that TD of human skin into h-iNSC(TE) is a platform for creating tumor-homing cytotoxic cell therapies for cancer,where the potential to avoid carrier rejection could maximize treatment durability in human trials. View Publication

Cardiac malformations and disease are the leading causes of death in the United States in live-born infants and adults,respectively. In both of these cases,a decrease in the number of functional cardiomyocytes often results in improper growth of heart tissue,wound healing complications,and poor tissue repair. The field of cardiac tissue engineering seeks to address these concerns by developing cardiac patches created from a variety of biomaterial scaffolds to be used in surgical repair of the heart. These scaffolds should be fully degradable biomaterial systems with tunable properties such that the materials can be altered to meet the needs of both in vitro culture (e.g. disease modeling) and in vivo application (e.g. cardiac patch). Current platforms do not utilize both structural anisotropy and proper cell-matrix contacts to promote functional cardiac phenotypes and thus there is still a need for critically sized scaffolds that mimic both the structural and adhesive properties of native tissue. To address this need,we have developed a silk-based scaffold platform containing cardiac tissue-derived extracellular matrix (cECM). These silk-cECM composite scaffolds have tunable architectures,degradation rates,and mechanical properties. Subcutaneous implantation in rats demonstrated that addition of the cECM to aligned silk scaffold led to 99% endogenous cell infiltration and promoted vascularization of a critically sized scaffold (10 × 5 × 2.5 mm) after 4 weeks in vivo. In vitro,silk-cECM scaffolds maintained the HL-1 atrial cardiomyocytes and human embryonic stem cell-derived cardiomyocytes and promoted a more functional phenotype in both cell types. This class of hybrid silk-cECM anisotropic scaffolds offers new opportunities for developing more physiologically relevant tissues for cardiac repair and disease modeling. View Publication

Transient lymphopenia is a hallmark of measles virus (MV)-induced immunosuppression. To address to what extent replenishment of the peripheral lymphocyte compartment from bone marrow (BM) progenitor/stem cells might be affected,we analyzed the interaction of wild-type MV with hematopoietic stem and progenitor cells (HS/PCs) and stroma cells in vitro. Infection of human CD34(+) HS/PCs or stroma cells with wild-type MV is highly inefficient yet noncytolytic. It occurs independently of CD150 in stroma cells but also in HS/PCs,where infection is established in CD34(+) CD150(-) and CD34(+) CD150(+) (in humans representing HS/PC oligopotent precursors) subsets. Stroma cells and HS/PCs can mutually transmit MV and may thereby create a possible niche for continuous viral exchange in the BM. Infected lymphocytes homing to this compartment may serve as sources for HS/PC or stroma cell infection,as reflected by highly efficient transmission of MV from both populations in cocultures with MV-infected B or T cells. Though MV exposure does not detectably affect the viability,expansion,and colony-forming activity of either CD150(+) or CD150(-) HS/PCs in vitro,it efficiently interferes with short- but not long-term hematopoietic reconstitution in NOD/SCID mice. Altogether,these findings support the hypothesis that MV accession of the BM compartment by infected lymphocytes may contribute to peripheral blood mononuclear cell lymphopenia at the level of BM suppression. View Publication

Relative quiescence is a defining characteristic of hematopoietic stem cells. Reasoning that inhibitory tone dominates control of stem cell cycling,we previously showed that mice engineered to be deficient in the cyclin-dependent kinase inhibitor,p21Cip1/Waf1 (p21),have an increased stem cell pool under homeostatic conditions. Since p21 was necessary to maintain stem cell quiescence and its absence sufficient to permit increased murine stem cell cycling,we tested whether reduction of p21 alone in human adult-derived stem cells could affect stem cell proliferation. We demonstrate here that interrupting p21 expression ex vivo resulted in expanded stem cell number and in vivo stem cell function compared with control,manipulated cells. Further,we demonstrate full multilineage reconstitution capability in cells where p21 expression was knocked down. Therefore,lifting the brake on cell proliferation by altering cell cycle checkpoints provides an alternative paradigm for increasing hematopoietic stem cell numbers. This approach may be useful for relative ex vivo human stem cell expansion. View Publication