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

We have tracked the fate of immature human B cells at a critical stage in their development when the mature B cell repertoire is shaped. We show that a major subset of bone marrow emigrant immature human B cells,the transitional 2 (T2) B cells,homes to gut-associated lymphoid tissue (GALT) and that most T2 B cells isolated from human GALT are activated. Activation in GALT is a previously unknown potential fate for immature human B cells. The process of maturation from immature transitional B cell through to mature naive B cell includes the removal of autoreactive cells from the developing repertoire,a process which is known to fail in systemic lupus erythematosus (SLE). We observe that immature B cells in SLE are poorly equipped to access the gut and that gut immune compartments are depleted in SLE. Thus,activation of immature B cells in GALT may function as a checkpoint that protects against autoimmunity. In healthy individuals,this pathway may be involved in generating the vast population of IgA plasma cells and also the enigmatic marginal zone B cell subset that is poorly understood in humans. View Publication

In this study,we developed a cell system to study TCF4 in human oligodendrocyte differentiation,showed that TCF4 regulates human oligodendroglial differentiation in a dose-dependent manner,and established a system to dissect TCF4 function in a human tissue–like context. Heterozygous mutations of TCF4 in humans cause Pitt–Hopkins syndrome,a neurodevelopmental disease associated with intellectual disability and brain malformations. Although most studies focus on the role of TCF4 in neural stem cells and neurons,we here set out to assess the implication of TCF4 for oligodendroglial differentiation. We discovered that both monoallelic and biallelic mutations in TCF4 result in a diminished capacity to differentiate human neural progenitor cells toward myelinating oligodendrocytes through the forced expression of the transcription factors SOX10,OLIG2,and NKX6.2. Using this experimental strategy,we established a novel organoid model,which generates oligodendroglial cells within a human neurogenic tissue–like context. Also,here we found a reduced ability of TCF4 heterozygous cells to differentiate toward oligodendroglial cells. In sum,we establish a role of human TCF4 in oligodendrocyte differentiation and provide a model system,which allows to dissect the disease etiology in a human tissue–like context. View Publication

Human noroviruses (HuNoVs) are the leading cause of nonbacterial gastroenteritis worldwide. Histo-blood group antigen (HBGA) expression is an important susceptibility factor for HuNoV infection based on controlled human infection models and epidemiologic studies that show an association of secretor status with infection caused by several genotypes. The fucosyltransferase 2 gene (FUT2) affects HBGA expression in intestinal epithelial cells; secretors express a functional FUT2 enzyme,while nonsecretors lack this enzyme and are highly resistant to infection and gastroenteritis caused by many HuNoV strains. These epidemiologic associations are confirmed by infections in stem cell-derived human intestinal enteroid (HIE) cultures. GII.4 HuNoV does not replicate in HIE cultures derived from nonsecretor individuals,while HIEs from secretors are permissive to infection. However,whether FUT2 expression alone is critical for infection remains unproven,since routinely used secretor-positive transformed cell lines are resistant to HuNoV replication. To evaluate the role of FUT2 in HuNoV replication,we used CRISPR or overexpression to genetically manipulate FUT2 gene function to produce isogenic HIE lines with or without FUT2 expression. We show that FUT2 expression alone affects both HuNoV binding to the HIE cell surface and susceptibility to HuNoV infection. These findings indicate that initial binding to a molecule(s) glycosylated by FUT2 is critical for HuNoV infection and that the HuNoV receptor is present in nonsecretor HIEs. In addition to HuNoV studies,these isogenic HIE lines will be useful tools to study other enteric microbes where infection and/or disease outcome is associated with secretor status.IMPORTANCE Several studies have demonstrated that secretor status is associated with susceptibility to human norovirus (HuNoV) infection; however,previous reports found that FUT2 expression is not sufficient to allow infection with HuNoV in a variety of continuous laboratory cell lines. Which cellular factor(s) regulates susceptibility to HuNoV infection remains unknown. We used genetic manipulation of HIE cultures to show that secretor status determined by FUT2 gene expression is necessary and sufficient to support HuNoV replication based on analyses of isogenic lines that lack or express FUT2. Fucosylation of HBGAs is critical for initial binding and for modification of another putative receptor(s) in HIEs needed for virus uptake or uncoating and necessary for successful infection by GI.1 and several GII HuNoV strains. View Publication

Immunotherapy has increased overall survival of metastatic cancer patients,and cancer antigens are promising vaccine targets. To fulfill the promise,appropriate tailoring of the vaccine formulations to mount in vivo cytotoxic T cell (CTL) responses toward co-delivered cancer antigens is essential. Previous development of therapeutic cancer vaccines has largely been based on studies in mice,and the majority of these candidate vaccines failed to induce therapeutic responses in the subsequent human clinical trials. Given that antigen dose and vaccine volume in pigs are translatable to humans and the porcine immunome is closer related to the human counterpart,we here introduce pigs as a supplementary large animal model for human cancer vaccine development. IDO and RhoC,both important in human cancer development and progression,were used as vaccine targets and 12 pigs were immunized with overlapping 20mer peptides spanning the entire porcine IDO and RhoC sequences formulated in CTL-inducing adjuvants: CAF09,CASAC,Montanide ISA 51 VG,or PBS. Taking advantage of recombinant swine MHC class I molecules (SLAs),the peptide-SLA complex stability was measured for 198 IDO- or RhoC-derived 9-11mer peptides predicted to bind to SLA-1(*)04:01,-1(*)07:02,-2(*)04:01,-2(*)05:02,and/or -3(*)04:01. This identified 89 stable (t½ ≥ 0.5 h) peptide-SLA complexes. By IFN-$\gamma$ release in PBMC cultures we monitored the vaccine-induced peptide-specific CTL responses,and found responses to both IDO- and RhoC-derived peptides across all groups with no adjuvant being superior. These findings support the further use of pigs as a large animal model for vaccine development against human cancer. View Publication

Transplantation of engineered hematopoietic stem/progenitor cells (HSPCs) showed curative potential in patients affected by neurometabolic diseases treated in early stage. Favoring the engraftment and maturation of the engineered HSPCs in the central nervous system (CNS) could allow enhancing further the therapeutic potential of this approach. Here we unveil that HSPCs haplo-insufficient at the Cx3cr1 (Cx3cr1 −/+ ) locus are favored in central nervous system (CNS) engraftment and generation of microglia-like progeny cells (MLCs) as compared to wild type (Cx3cr1 +/+ ) HSPCs upon transplantation in mice. Based on this evidence,we have developed a CRISPR-based targeted gene addition strategy at the human CX3CR1 locus resulting in an enhanced ability of the edited human HSPCs to generate mature MLCs upon transplantation in immunodeficient mice,and in lineage specific,regulated and robust transgene expression. This approach,which benefits from the modulation of pathways involved in microglia maturation and migration in haplo-insufficient cells,may broaden the application of HSPC gene therapy to a larger spectrum of neurometabolic and neurodegenerative diseases. Subject terms: Targeted gene repair,Haematopoietic stem cells,Microglial cells View Publication

Ectopic delivery of HOXB4 elicits the expansion of engrafting hematopoietic stem cells (HSCs). We hypothesized that inhibition of tumor necrosis factor-alpha (TNF-alpha) signaling may be central to the self-renewal signature of HOXB4. Because HSCs derived from Fanconi anemia (FA) knockout mice are hypersensitive to TNF-alpha,we studied Fancc(-/-) HSCs to determine the physiologic effects of HOXB4 on TNF-alpha sensitivity and the relationship of these effects to the engraftment defect of FA HSCs. Overexpression of HOXB4 reversed the in vitro hypersensitivity to TNF-alpha of Fancc(-/-) HSCs and progenitors (P) and partially rescued the engraftment defect of these cells. Coexpression of HOXB4 and the correcting FA-C protein resulted in full correction compared with wild-type (WT) HSCs. Ectopic expression of HOXB4 resulted in a reduction in both apoptosis and reactive oxygen species in Fancc(-/-) but not WT HSC/P. HOXB4 overexpression was also associated with a significant reduction in surface expression of TNF-alpha receptors on Fancc(-/-) HSC/P. Finally,enhanced engraftment was seen even when HOXB4 was expressed in a time-limited fashion during in vivo reconstitution. Thus,the HOXB4 engraftment signature may be related to its effects on TNF-alpha signaling,and this pathway may be a molecular target for timed pharmacologic manipulation of HSC during reconstitution. View Publication

Prenatal lethality associated with mouse knockout of Mettl16,a recently identified RNA N6-methyladenosine (m 6 A) methyltransferase,has hampered characterization of the essential role of METTL16-mediated RNA m 6 A modification in early embryonic development. Here,using cross-species single-cell RNA sequencing analysis,we found that during early embryonic development,METTL16 is more highly expressed in vertebrate hematopoietic stem and progenitor cells (HSPCs) than other methyltransferases. In Mettl16-deficient zebrafish,proliferation capacity of embryonic HSPCs is compromised due to G1/S cell cycle arrest,an effect whose rescue requires Mettl16 with intact methyltransferase activity. We further identify the cell-cycle transcription factor mybl2b as a directly regulated by Mettl16-mediated m 6 A modification. Mettl16 deficiency resulted in the destabilization of mybl2b mRNA,likely due to lost binding by the m 6 A reader Igf2bp1 in vivo. Moreover,we found that the METTL16-m 6 A- MYBL2 -IGF2BP1 axis controlling G1/S progression is conserved in humans. Collectively,our findings elucidate the critical function of METTL16-mediated m 6 A modification in HSPC cell cycle progression during early embryonic development. View Publication

Deamination of the nucleoside analogues ARA-C and 5-AZA-CdR by CR deaminase results in a loss of antileukemic activity. To prevent the inactivation of these analogues,inhibitors of CR deaminase may prove to be useful agents. In the present study we investigated the effects of the deaminase inhibitors Zebularine,5-F-Zebularine,and diazepinone riboside on the deamination of CR,ARA-C,and 5-AZA-CdR using highly purified human CR deaminase (EC 3.5.4.5). These inhibitors produced a competitive type of inhibition with each substrate,the potency of which followed the patterns diazepinone riboside greater than 5-F-Zebularine and THU greater than Zebularine. 5-AZA-CdR was more sensitive than ARA-C to the inhibition produced by these deaminase inhibitors. The inhibition constants for diazepinone riboside lay in the range of 5-15 nM,suggesting that this inhibitor could be an excellent candidate for use in combination chemotherapy with either ARA-C or 5-AZA-CdR in patients with leukemia. View Publication

Pluripotent stem cell derived hepatocyte-like cells (hPSC-HLCs) are an attractive alternative to primary human hepatocytes (PHHs) used in applications ranging from therapeutics to drug safety testing studies. It would be critical to improve and maintain mature hepatocyte functions of the hPSC-HLCs,especially for long-term studies. If 3D culture systems were to be used for such purposes,it would be important that the system can support formation and maintenance of optimal-sized spheroids for long periods of time,and can also be directly deployed in liver drug testing assays. We report the use of 3-dimensional (3D) cellulosic scaffold system for the culture of hPSC-HLCs. The scaffold has a macroporous network which helps to control the formation and maintenance of the spheroids for weeks. Our results show that culturing hPSC-HLCs in 3D cellulosic scaffolds increases functionality,as demonstrated by improved urea production and hepatic marker expression. In addition,hPSC-HLCs in the scaffolds exhibit a more mature phenotype,as shown by enhanced cytochrome P450 activity and induction. This enables the system to show a higher sensitivity to hepatotoxicants and a higher degree of similarity to PHHs when compared to conventional 2D systems. These results suggest that 3D cellulosic scaffolds are ideal for the long-term cultures needed to mature hPSC-HLCs. The mature hPSC-HLCs with improved cellular function can be continually maintained in the scaffolds and directly used for hepatotoxicity assays,making this system highly attractive for drug testing applications. View Publication

A novel cardiomimetic biohybrid material,termed as the human ventricular cardiac anisotropic sheet (hvCAS) is reported. Well-characterized human pluripotent stem-cell-derived ventricular cardiomyocytes are strategically aligned to reproduce key electrophysiological features of native human ventricle,which,along with specific selection criteria,allows for a direct visualization of arrhythmic spiral re-entry and represents a revolutionary tool to assess preclinical drug-induced arrhythmogenicity. View Publication

Transcriptional profiling of differentiating human embryonic stem cells (hESCs) revealed that MIXL1-positive mesodermal precursors were enriched for transcripts encoding the G-protein-coupled APELIN receptor (APLNR). APLNR-positive cells,identified by binding of the fluoresceinated peptide ligand,APELIN (APLN),or an anti-APLNR mAb,were found in both posterior mesoderm and anterior mesendoderm populations and were enriched in hemangioblast colony-forming cells (Bl-CFC). The addition of APLN peptide to the media enhanced the growth of embryoid bodies (EBs),increased the expression of hematoendothelial genes in differentiating hESCs,and increased the frequency of Bl-CFCs by up to 10-fold. Furthermore,APLN peptide also synergized with VEGF to promote the growth of hESC-derived endothelial cells. These studies identified APLN as a novel growth factor for hESC-derived hematopoietic and endothelial cells. View Publication