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

Objective: Human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) constitute unique sources of pluripotent cells,although the molecular mechanisms involved in their differentiation into specific lineages are just beginning to be defined. Here we evaluated the ability of MEDII (medium conditioned by HepG2 cells,a human hepatocarcinoma cell line) to selectively enhance generation of mesodermal derivatives,including hematopoietic cells,from hESCs and hiPSCs. Materials and Methods: Test cells were exposed to MEDII prior to being placed in conditions that promote embryoid body (EB) formation. Hematopoietic activity was measured by clonogenic assays,flow cytometry,quantitative real-time polymerase chain reaction of specific transcript complementary DNAs and the ability of cells to repopulate sublethally irradiated nonobese diabetic/severe combined immunodeficient interleukin-2 receptor ??-chain-null mice for almost 1 year. Results: Exposure of both hESCs and hiPSCs to MEDII induced a rapid and preferential differentiation of hESCs into mesodermal elements. Subsequently produced EBs showed a further enhanced expression of transcripts characteristic of multiple mesodermal lineages,and a concurrent decrease in endodermal and ectodermal cell transcripts. Frequency of all types of clonogenic hematopoietic progenitors in subsequently derived EBs was also increased. In vivo assays of MEDII-treated hESC-derived EBs also showed they contained cells able to undertake low-level but longterm multilineage repopulation of primary and secondary nonobese diabetic/severe combined immunodeficient interleukin-2 receptor ??-chain-null mice. Conclusions: MEDII treatment of hESCs and hiPSCs alike selectively enhances their differentiation into mesodermal cells and allows subsequent generation of detectable levels of hematopoietic progenitors with in vitro and in vivo differentiating activity. ?? 2009 ISEH - Society for Hematology and Stem Cells. View Publication

BACKGROUND Ageing is a complex phenomenon that leads to decreased proliferative activity,loss of function of the cells,and cellular senescence. Senescence of the immune system exacerbates individual's immune response,both humoral and cellular but increases the frequency of infections. We hypothesized that physiological ageing of adaptive immune system occurs in recipients of allogeneic hematopoietic cells transplant (allo-HCT) at faster rate when compared to their respective donors since the small number of donor cells undergo immense proliferative stress restoring recipients hematopoiesis. We compared molecular characterizations of ageing between recipients and donors of allo-HCT: telomeric length and immunophenotypic changes in main lymphocyte subsets - CD4+,CD8+,CD19+,CD56+. RESULTS Median telomeric length (TL) of CD8+ lymphocytes was significantly longer in donors compared to recipients (on average 2,1 kb and 1,7 kb respectively,p??=??0,02). Similar trends were observed for CD4+ and CD19+ although the results did not reach statistical significance. We have also found trends in the immunophenotype between recipients and donors in the subpopulations of CD4+ (na{\{i}}ve and effector memory) CD8+ Eomes+ and B-lymphocytes (B1 and B2). Lower infection risk recipients had also a significantly greater percentage of NK cells (22 3%) than high-risk patients (9 3%) p??=??0 04. CONCLUSION Our data do not support the initial hypothesis of accelerated aging in the long term all-HCT recipients with the exception of the recipients lymphocytes (mainly CD8+) which present some molecular features characteristic for physiological ageing (telomeric shortening immunophenotype) when compared to their respective donors. However a history of lower infection numbers in HCT recipients seems to be associated with increased percentage of NK cells. The history of GVHD seems not to affect the rate of ageing. Therefore it is safe to conclude that the observed subtle differences between recipients' and donors' cells result mainly from the proliferative stress in the early period after allo-HCT and the difference between hosts' and recipients' microenvironments." View Publication

BackgroundOP9 mouse stromal cell line has been widely used to induce differentiation of human embryonic stem cells (hESCs) into hematopoietic stem/progenitor cells (HSPCs). However,the whole co-culture procedure usually needs 14–18 days,including preparing OP9 cells at least 4 days. Therefore,the inefficient differentiation system is not appreciated. We aimed to optimize the culture conditions to improve differentiation efficiency.MethodsIn the experimental group,we set six different densities of OP9 cells and just cultured them for 24 h before co-culture,and in the control group,OP9 cells were cultured for 4 days to reach an overgrown state before co-culture. Then we compared the hematopoietic differentiation efficiency among them.ResultsOP9 cells were randomly assigned into two groups. In the experimental group,six different plated numbers of OP9 cells were cultured for 1 day before co-culture with hESCs. In contrast,in the control group,OP9 cells were cultured for 4 days at a total number of 3.1 × 104 cells/cm2 in a 6-well plate to reach an overgrown state before co-culture. Hematopoietic differentiation was evaluated with CD34 immunostaining,and compared between these two groups. We could not influence the differentiation efficiency of OP9 cells with a total number of 10.4 × 104 cells/cm2 in a 6-well plate which was cultured just for 1 day,followed by co-culture with hESCs. It reached the same differentiation efficiency 5 days earlier than the control group.ConclusionThe peak of CD34 + cells appeared 2 days earlier compared to the control group. A total number of 1.0 × 106 cells in a 6-well plate for OP9 cells was appropriate to have high differentiation efficiency. View Publication

Neurogenesis in the subventricular zone (SVZ) is regulated by diffusible factors and cell-cell contacts. In vivo,SVZ stem cells are associated with the abluminal surface of blood vessels and such interactions are thought to regulate their neurogenic capacity. SVZ neural stem cells (NSCs) have been described to contact endothelial-derived laminin via α6β1 integrin. To elucidate whether heterocellular contacts with brain endothelial cells (BEC) regulate SVZ cells neurogenic capacities,cocultures of SVZ neurospheres and primary BEC,both obtained from C57BL/6 mice,were performed. The involvement of laminin-integrin interactions in SVZ homeostasis was tested in three ways. Firstly,SVZ cells were analyzed following incubation of BEC with the protein synthesis inhibitor cycloheximide (CHX) prior to coculture,a treatment expected to decrease membrane proteins. Secondly,SVZ cells were cocultured with BEC in the presence of an anti-α6 integrin neutralizing antibody. Thirdly,BEC were cultured with β1-/- SVZ cells. We showed that contact with BEC supports,at least in part,proliferation and stemness of SVZ cells,as evaluated by the number of BrdU positive (+) and Sox2+ cells in contact with BEC. These effects are dependent on BEC-derived laminin binding to α6β1 integrin and are decreased in cocultures incubated with anti-α6 integrin neutralizing antibody and in cocultures with SVZ β1-/- cells. Moreover,BEC-derived laminin sustains stemness in SVZ cell cultures via activation of the Notch and mTOR signaling pathways. Our results show that BEC/SVZ interactions involving α6β1 integrin binding to laminin,contribute to SVZ cell proliferation and stemness. View Publication

In the adult bone marrow (BM),endothelial cells (ECs) are an integral component of the hematopoietic stem cell (HSC)-supportive niche,which modulates HSC activity by producing secreted and membrane-bound paracrine signals. Within the BM,distinct vascular arteriole,transitional,and sinusoidal EC subtypes display unique paracrine expression profiles and create anatomically-discrete microenvironments. However,the relative contributions of vascular endothelial subtypes in supporting hematopoiesis is unclear. Moreover,constitutive expression and off-target activity of currently available endothelial-specific and endothelial-subtype-specific murine cre lines potentially confound data analysis and interpretation. To address this,we describe two tamoxifen-inducible cre -expressing lines,Vegfr3-creER T2 and Cx40-creER T2,that efficiently label sinusoidal/transitional and arteriole endothelium respectively in adult marrow,without off-target activity in hematopoietic or perivascular cells. Utilizing an established mouse model in which cre -dependent recombination constitutively-activates MAPK signaling within adult endothelium,we identify arteriole ECs as the driver of MAPK-mediated hematopoietic dysfunction. These results define complementary tamoxifen-inducible creER T2 -expressing mouse lines that label functionally-discrete and non-overlapping sinusoidal/transitional and arteriole EC populations in the adult BM,providing a robust toolset to investigate the differential contributions of vascular subtypes in maintaining hematopoietic homeostasis. The online version contains supplementary material available at 10.1007/s12015-024-10703-9. View Publication

Gamma-delta (??) T cells recognize antigens in a major histocompatibility complex (MHC) independent and have cytotoxic capability. Human immunodeficiency virus (HIV) infection reduces the proportion of the V?2 cell subset compared to the V?1 cell subset of ?? T cells in the blood in most infected individuals,except for elite controllers. The capacity of V?2 T cells to kill HIV-infected targets has been demonstrated in vitro,albeit in vivo confirmatory studies are lacking. Here,we provide the first characterization of ?? T cell-HIV interactions in bone marrow-liver-thymus (BLT) humanized mice and examined the immunotherapeutic potential of V?2 T cells in controlling HIV replication in vivo. We demonstrate a reduced proportion of V?2 T cells and an increased proportion of V?1 T cells in HIV-infected BLT humanized mice,like in HIV-positive individuals. HIV infection in BLT humanized mice also impaired the ex vivo expansion of V?2 T cells,like in HIV-positive individuals. Adoptive transfer of activated V?2 T cells did not control HIV replication during cell-associated HIV transmission in BLT humanized mice but instead exacerbated viremia,suggesting that V?2 T cells may serve as early targets for HIV replication. Our findings demonstrate that BLT humanized mice can model ?? T cell-HIV interactions in vivo. View Publication

Exposure of murine bone marrow (BM) cells to ionizing radiation (IR; 4 Gy) resulted in textgreater95% inhibition of the frequency of various day types of cobblestone area-forming cells in association with the induction of apoptosis in hematopoietic stem cell alike cells (Lin(-) ScaI(+) c-kit(+) cells; IR: 64.8 +/- 0.4% versus control: 20.4 +/- 0.5%; P textless 0.001) and progenitors (Lin(-) ScaI(-) c-kit(+) cells; IR: 46.2 +/- 1.4% versus control: 7.8 +/- 0.5%; P textless 0.001). Incubation of murine BM cells with busulfan (BU; 30 micro M) for 6 h also inhibited the cobblestone area-forming cell frequency but failed to cause a significant increase in apoptosis in these two types of hematopoietic cells. After 5 weeks of long-term BM cell culture,33% and 72% of hematopoietic cells survived IR- and BU-induced damage,respectively,as compared with control cells,but they could not form colony forming units-granulocyte macrophages. Moreover,these surviving cells expressed an increased level of senescence-associated beta-galactosidase,p16(Ink4a),and p19(Arf). These findings suggest that IR inhibits the function of hematopoietic stem cell alike cells and progenitors primarily by inducing apoptosis,whereas BU does so mainly by inducing premature senescence. In addition,induction of premature senescence in BM hematopoietic cells also contributes to IR-induced inhibition of their hematopoietic function. Interestingly,the induction of hematopoietic cell senescence by IR,but not by BU,was associated with an elevation in p53 and p21(Cip1/Waf1) expression. This suggests that IR induces hematopoietic cell senescence in a p53-p21(Cip1/Waf1)-dependent manner,whereas the induction of senescence by BU bypasses the p53-p21(Cip1/Waf1) pathway. View Publication

Ecotropic viral integration site-1 (Evi-1) is a nuclear transcription factor that plays an essential role in the regulation of hematopoietic stem cells. Aberrant expression of Evi-1 has been reported in up to 10% of patients with acute myeloid leukemia and is a diagnostic marker that predicts a poor outcome. Although chromosomal rearrangement involving the Evi-1 gene is one of the major causes of Evi-1 activation,overexpression of Evi-1 is detected in a subgroup of acute myeloid leukemia patients without any chromosomal abnormalities,which indicates the presence of other mechanisms for Evi-1 activation. In this study,we found that Evi-1 is frequently up-regulated in bone marrow cells transformed by the mixed-lineage leukemia (MLL) chimeric genes MLL-ENL or MLL-AF9. Analysis of the Evi-1 gene promoter region revealed that MLL-ENL activates transcription of Evi-1. MLL-ENL-mediated up-regulation of Evi-1 occurs exclusively in the undifferentiated hematopoietic population,in which Evi-1 particularly contributes to the propagation of MLL-ENL-immortalized cells. Furthermore,gene-expression analysis of human acute myeloid leukemia cases demonstrated the stem cell-like gene-expression signature of MLL-rearranged leukemia with high levels of Evi-1. Our findings indicate that Evi-1 is one of the targets of MLL oncoproteins and is selectively activated in hematopoietic stem cell-derived MLL leukemic cells. View Publication

The most frequent translocation t(8;21) in acute myeloid leukemia (AML) generates the chimeric AML1/ETO protein,which blocks differentiation and induces self-renewal in hematopoietic progenitor cells. The underlying mechanisms mediating AML1/ETO-induced self-renewal are largely unknown. Using expression microarray analysis,we identified the Groucho-related amino-terminal enhancer of split (AES) as a consistently up-regulated AML1/ETO target. Elevated levels of AES mRNA and protein were confirmed in AML1/ETO-expressing leukemia cells,as well as in other AML specimens. High expression of AES mRNA or protein was associated with improved survival of AML patients,even in the absence of t(8;21). On a functional level,knockdown of AES by RNAi in AML1/ETO-expressing cell lines inhibited colony formation. Similarly,self-renewal induced by AML1/ETO in primary murine progenitors was inhibited when AES was decreased or absent. High levels of AES expression enhanced formation of immature colonies,serial replating capacity of primary cells,and colony formation in colony-forming unit-spleen assays. These findings establish AES as a novel AML1/ETO-induced target gene that plays an important role in the self-renewal phenotype of t(8;21)-positive AML. View Publication

Juvenile myelomonocytic leukemia (JMML) is a rare aggressive myelodysplastic/myeloproliferative neoplasm of early childhood,initiated by RAS-activating mutations. Genomic analyses have recently described JMML mutational landscape; however,the nature of JMML-propagating cells (JMML-PCs) and the clonal architecture of the disease remained until now elusive. Combining genomic (exome,RNA-seq),Colony forming assay and xenograft studies,we detect the presence of JMML-PCs that faithfully reproduce JMML features including the complex/nonlinear organization of dominant/minor clones,both at diagnosis and relapse. Further integrated analysis also reveals that although the mutations are acquired in hematopoietic stem cells,JMML-PCs are not always restricted to this compartment,highlighting the heterogeneity of the disease during the initiation steps. We show that the hematopoietic stem/progenitor cell phenotype is globally maintained in JMML despite overexpression of CD90/THY-1 in a subset of patients. This study shed new lights into the ontogeny of JMML,and the identity of JMML-PCs,and provides robust models to monitor the disease and test novel therapeutic approaches. View Publication