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

The response to programmed death-1 (PD-1) blockade varies in hepatocellular carcinoma (HCC). We utilize a panel of 16 serum factors to show that a circulating level of serum amyloid A (SAA) > 20.0 mg/L has the highest accuracy in predicting anti-PD-1 resistance in HCC. Further experiments show a correlation between peritumoral SAA expression and circulating SAA levels in patients with progressive disease after PD-1 inhibition. In vitro experiments demonstrate that SAA induces neutrophils to express PD-L1 through glycolytic activation via an LDHA/STAT3 pathway and to release oncostatin M,thereby attenuating cytotoxic T cell function. In vivo,genetic or pharmacological inhibition of STAT3 or SAA eliminates neutrophil-mediated immunosuppression and enhances antitumor efficacy of anti-PD-1 treatment. This study indicates that SAA may be a critical inflammatory cytokine implicated in anti-PD-1 resistance in HCC. Targeting SAA-induced PD-L1+ neutrophils through STAT3 or SAA inhibition may present a potential approach for overcoming anti-PD1 resistance. The reasons for why hepatocellular carcinoma (HCC) is unresponsive to anti-PD-1 inhibition in some patients is not fully understood. Here the authors use human samples and mice tumour models to implicate serum amyloid A and STAT3 signalling involvement in the resistance to anti-PD1 immunotherapy in HCC. View Publication

The novel immunosuppressant FTY720 activates sphingosine 1-phosphate receptors (S1PRs) that affect responsiveness of lymphocytes to chemokines such as stromal cell-derived factor 1 (SDF-1),resulting in increased lymphocyte homing to secondary lymphoid organs. Since SDF-1 and its receptor CXCR4 are also involved in bone marrow (BM) homing of hematopoietic stem and progenitor cells (HPCs),we analyzed expression of S1PRs and the influence of FTY720 on SDF-1/CXCR4-mediated effects in human HPCs. By reverse transcriptase-polymerase chain reaction (RT-PCR),S1PRs were expressed in mobilized CD34+ HPCs,particularly in primitive CD34+/CD38- cells. Incubation of HPCs with FTY720 resulted in prolonged SDF-1-induced calcium mobilization and actin polymerization,and substantially increased SDF-1-dependent in vitro transendothelial migration,without affecting VLA-4,VLA-5,and CXCR4 expression. In nonobese diabetic-severe combined immunodeficient (NOD/SCID) mice,the number of CD34+/CD38- cells that homed to the BM after 18 hours was significantly raised by pretreatment of animals and cells with FTY720,tending to result in improved engraftment. In addition,in vitro growth of HPCs (week-5 cobblestone area-forming cells [CAFCs]) was 2.4-fold increased. We conclude that activation of S1PRs by FTY720 increases CXCR4 function in HPCs both in vitro and in vivo,supporting homing and proliferation of HPCs. In the hematopoietic microenvironment,S1PRs are involved in migration and maintenance of HPCs by modulating the effects of SDF-1. View Publication

Human embryonic stem cells (hESCs) hold enormous promise for regenerative medicine. Typically,hESC-based applications would require their in vitro differentiation into a desirable homogenous cell population. A major challenge of the current hESC differentiation paradigm is the inability to effectively capture and,in the long-term,stably expand primitive lineage-specific stem/precursor cells that retain broad differentiation potential and,more importantly,developmental stage-specific differentiation propensity. Here,we report synergistic inhibition of glycogen synthase kinase 3 (GSK3),transforming growth factor β (TGF-β),and Notch signaling pathways by small molecules can efficiently convert monolayer cultured hESCs into homogenous primitive neuroepithelium within 1 wk under chemically defined condition. These primitive neuroepithelia can stably self-renew in the presence of leukemia inhibitory factor,GSK3 inhibitor (CHIR99021),and TGF-β receptor inhibitor (SB431542); retain high neurogenic potential and responsiveness to instructive neural patterning cues toward midbrain and hindbrain neuronal subtypes; and exhibit in vivo integration. Our work uniformly captures and maintains primitive neural stem cells from hESCs. View Publication

Microbial growth in damp indoor environments has been correlated with risks to human health. This study was aimed to determine the cytotoxicity of 1-octen-3-ol (mushroom alcohol")� View Publication

Physical stimuli can act in either a synergistic or antagonistic manner to regulate cell fate decisions,but it is less clear whether insoluble signals alone can direct human pluripotent stem (hPS) cell differentiation into specialized cell types. We previously reported that stiff materials promote nuclear localization of the Yes-associated protein (YAP) transcriptional coactivator and support long-term self-renewal of hPS cells. Here,we show that even in the presence of soluble pluripotency factors,compliant substrata inhibit the nuclear localization of YAP and promote highly efficient differentiation of hPS cells into postmitotic neurons. In the absence of neurogenic factors,the effective substrata produce neurons rapidly (2 wk) and more efficiently (textgreater75%) than conventional differentiation methods. The neurons derived from substrate induction express mature markers and possess action potentials. The hPS differentiation observed on compliant surfaces could be recapitulated on stiff surfaces by adding small-molecule inhibitors of F-actin polymerization or by depleting YAP. These studies reveal that the matrix alone can mediate differentiation of hPS cells into a mature cell type,independent of soluble inductive factors. That mechanical cues can override soluble signals suggests that their contributions to early tissue development and lineage commitment are profound. View Publication

Terahertz (THz) radiation was proposed recently for use in various applications,including medical imaging and security scanners. However,there are concerns regarding the possible biological effects of non-ionising electromagnetic radiation in the THz range on cells. Human embryonic stem cells (hESCs) are extremely sensitive to environmental stimuli,and we therefore utilised this cell model to investigate the non-thermal effects of THz irradiation. We studied DNA damage and transcriptome responses in hESCs exposed to narrow-band THz radiation (2.3 THz) under strict temperature control. The transcription of approximately 1% of genes was subtly increased following THz irradiation. Functional annotation enrichment analysis of differentially expressed genes revealed 15 functional classes,which were mostly related to mitochondria. Terahertz irradiation did not induce the formation of γH2AX foci or structural chromosomal aberrations in hESCs. We did not observe any effect on the mitotic index or morphology of the hESCs following THz exposure. View Publication

Human somatic stem cells such as mesenchymal stem cells (hMSCs) have the capacity to differentiate into mesenchymal tissue lineages and to alter immune regulatory functions. As such,they hold promise for use in stem cell-based therapies. However,no method is currently available to evaluate the actual differentiation capacity of hMSCs prior to cell transplantation. Previously,we performed a comprehensive glycan profiling of adipose-derived hMSCs using high-density lectin microarray and demonstrated that $$2-6-sialylation is a marker of the differentiation potential of these cells. Nevertheless,no information was available about the structural details of these of $$2-6-sialylated glycans. Here we used high performance liquid chromatography (HPLC) analysis combined with mass spectrometry (MS) to perform a structural and quantitative glycome analysis targeting both N- and O-glycans derived from early (with differentiation ability) and late (without differentiation ability) passages of adipose tissue-derived hMSCs. Findings in these cells were compared with those from human induced pluripotent stem cells (hiPSCs),human dermal fibroblasts (hFibs) and cartilage tissue-derived chondrocytes. A higher percentage of $$2-6-sialylated N-glycans was detected in early passage cells (24-28 % of sialylated N-glycans) compared with late passage cells (13-15 %). A major $$2-6-sialylated N-glycan structure detected in adipose-derived hMSCs was that of mono-sialylated biantennary N-glycan. Similar results were obtained for the cartilage tissue-derived chondrocytes,Yub621c (28 % for passage 7 and 5 % for passage 28). In contrast,no significant differences were observed between early and late passage hMSCs with respect to $$2-6-sialylated O-glycan percentages. These results demonstrate that levels of $$2-6-sialylated N-glycans,but not O-glycans,could be used as markers of the differential potential of hMSCs. View Publication

Human embryonic stem (hES) cells have enormous potential for clinical applications. However,one major challenge is to achieve high cell recovery rate after cryopreservation. Understanding how the conventional cryopreservation protocol fails to protect the cells is a prerequisite for developing efficient and successful cryopreservation methods for hES cell lines and banks. We investigated how the stimuli from cryopreservation result in apoptosis,which causes the low cell recovery rate after cryopreservation. The level of reactive oxygen species (ROS) is significantly increased,F-actin content and distribution is altered,and caspase-8 and caspase-9 are activated after cryopreservation. p53 is also activated and translocated into nucleus. During cryopreservation apoptosis is induced by activation of both caspase-8 through the extrinsic pathway and caspase-9 through the intrinsic pathway. However,exactly how the extrinsic pathway is activated is still unclear and deserves further investigation. View Publication

Induced pluripotent stem (iPS) cells derived from terminally differentiated human fibroblasts are reprogrammed to possess stem cell like properties. However,the extent to which iPS cells exhibit unique properties of the human embryonic stem (hES) cell cycle remains to be established. hES cells are characterized by an abbreviated G1 phase (∼ 2.5 h) and accelerated organization of subnuclear domains that mediate the assembly of regulatory machinery for histone gene expression [i.e.,histone locus bodies (HLBs)]. We therefore examined cell cycle parameters of iPS cells in comparison to hES cells. Analysis of DNA synthesis [5-bromo-2'-deoxy-uridine (BrdU) incorporation],cell cycle distribution (FACS analysis and Ki67 staining) and subnuclear organization of HLBs [immunofluorescence microscopy and fluorescence in situ hybridization (FISH)] revealed that human iPS cells have a short G1 phase (∼ 2.5 h) and an abbreviated cell cycle (16-18 h). Furthermore,HLBs are formed and reorganized rapidly after mitosis (within 1.5-2 h). Thus,reprogrammed iPS cells have cell cycle kinetics and dynamic subnuclear organization of regulatory machinery that are principal properties of pluripotent hES cells. Our findings support the concept that the abbreviated cell cycle of hES and iPS cells is functionally linked to pluripotency. View Publication