CTLA-4 is thought to inhibit effector T cells both intrinsically, by competing with CD28 for B7 ligands, and extrinsically, through the action of regulatory T cells. We studied in vivo responses of normal and CTLA-4-deficient antigen-specific murine effector CD4+ T cells. In order to do these studies in a physiological model of immunity to foreign antigen, we transferred small numbers of congenically marked RAG2-deficient 5C.C7 T cells with either a normal or knockout allele of CTLA-4 into normal syngeneic B10.A recipient mice. The T cells were then activated by immunization with MCC peptide and LPS. To look for transcriptional signatures of negative regulation of T cell responses by CTLA-4, we used microarray analysis to compare transcripts in wild type and CTLA-4 KO 5C.C7 T cells four days after immunization. This is the first instance in which differences are observed in extent of accumulation of wild type and CTLA-4 KO 5C.C7 T cells.
Cutting edge: CTLA-4 on effector T cells inhibits in trans.
Specimen part
View SamplesA LHX4 transgenic reporter line with high specificity for developing mouse cone photoreceptors was identified and used to purify early stage cone photoreceptors for profiling by single cell RNA sequencing. Overall design: Collection of FACS-sorted LHX4::GFP+ E14.5 early cones and LHX4::GFP- retinal cells for further analysis.
Identification of Genes With Enriched Expression in Early Developing Mouse Cone Photoreceptors.
Specimen part, Cell line, Subject
View SamplesCure rates for patients with acute myeloid leukemia (AML) remain low despite ever-increasing dose intensity of cytotoxic therapy. In an effort to identify novel approaches to AML therapy, we recently reported a new method of chemical screening based on the modulation of a gene expression signature of interest. We applied this approach to the discovery of AML-differentiation-promoting compounds. Among the compounds inducing neutrophilic differentiation was DAPH1 (4,5-dianilinophthalimide), previously reported to inhibit epidermal growth factor receptor (EGFR) kinase activity. Here we report that the Food and Drug Administration (FDA)-approved EGFR inhibitor gefitinib similarly promotes the differentiation of AML cell lines and primary patient-derived AML blasts in vitro. Gefitinib induced differentiation based on morphologic assessment, nitro-blue tetrazolium reduction, cell-surface markers, genome-wide patterns of gene expression, and inhibition of proliferation at clinically achievable doses. Importantly, EGFR expression was not detected in AML cells, indicating that gefitinib functions through a previously unrecognized EGFR-independent mechanism. These studies indicate that clinical trials testing the efficacy of gefitinib in patients with AML are warranted.
Gefitinib induces myeloid differentiation of acute myeloid leukemia.
Disease, Disease stage, Cell line
View SamplesVarious mesenchymal cell types have been identified as critical components of the hematopoietic stem/progenitor cell (HSPC) niche. Although several groups have described the generation of mesenchyme from human pluripotent stem cells (hPSC), the capacity of such cells to support hematopoiesis has not been reported. Here we have demonstrated that distinct mesenchymal subpopulations co-emerge from mesoderm during hPSC differentiation. Despite co-expression of common mesenchymal markers (CD73, CD105, CD90, PDGFRß), a subset of cells defined as CD146++CD140alow supported functional HSPC ex vivo while CD146-CD140a+ cells drove differentiation. The CD146++ subset expressed genes associated with the HSPC niche and high levels of the Wnt inhibitors. HSPC support was contact-dependent and was mediated in part through JAG1 expression. Molecular profiling revealed remarkable transcriptional similarity between hPSC-derived CD146++ and primary human CD146++ perivascular cells. The derivation of diverse pools of mesenchymal populations from hPSC opens potential avenues to model their developmental and functional differences and to improve cell-based therapeutics from hPSC. Overall design: Our goal was to analyze and compare transcriptome of human pluripoten stem cell-derived mesenchyme (CD146++ and CD146-) with primary human lipoaspirate tissue-derived pericyte (CD146+) and CD146- mesenchymal populations.
Transcriptionally and Functionally Distinct Mesenchymal Subpopulations Are Generated from Human Pluripotent Stem Cells.
Specimen part, Subject
View SamplesWe used microarrays to determine how the quality and quantity of peptide-MHC impact TCR-induced gene expression in vivo.
Distinct influences of peptide-MHC quality and quantity on in vivo T-cell responses.
No sample metadata fields
View SamplesAlthough clonal studies of lineage potential have been extensively applied to organ specific stem and progenitor cells, much less is known about the clonal origins of lineages formed from the germ layers in early embryogenesis. We applied lentiviral tagging followed by vector integration site analysis (VISA) with high-throughput sequencing to investigate the ontogeny of the hematopoietic, endothelial and mesenchymal lineages as they emerge from human embryonic mesoderm. In contrast to studies that have used VISA to track differentiation of self-renewing stem cell clones that amplify significantly over time, we focused on a population of progenitor clones with limited self-renewal capability. Our analyses uncovered the critical influence of sampling on the interpretation of lentiviral tag sharing, particularly among complex populations with minimal clonal duplication. By applying a quantitative framework to estimate the degree of undersampling we revealed the existence of tripotent mesodermal progenitors derived from pluripotent stem cells, and the subsequent bifurcation of their differentiation into exclusively bipotent endothelial/hematopoietic or endothelial/mesenchymal progenitors. Overall design: Our goal was to analyze transcriptome changes of mesoderm commitment during human embyronic stem cells differentiation. RNA were extracted and sequenced from two populations, human embryonic stem cells (H1 line) and the human early mesodermal progenitors (hEMP) differentiated from H1.
Transcriptionally and Functionally Distinct Mesenchymal Subpopulations Are Generated from Human Pluripotent Stem Cells.
No sample metadata fields
View SamplesAnalysis of knockdown of SDHD with or without knockdown of CDKN1C or SLC22A18 at gene expression level.
Parent-of-origin tumourigenesis is mediated by an essential imprinted modifier in SDHD-linked paragangliomas: SLC22A18 and CDKN1C are candidate tumour modifiers.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification of AML1-ETO modulators by chemical genomics.
Cell line
View SamplesSomatic rearrangements of transcription factors are common abnormalities in the acute leukemias. With rare exception, however, the resultant protein products have remained largely intractable as pharmacologic targets. One example is AML1-ETO, the most common translocation reported in acute myeloid leukemia (AML). To identify AML1-ETO modulators, we screened a small molecule library using a chemical genomic approach. Gene expression signatures were used as surrogates for the expression versus loss of the translocation in AML1-ETO-expressing cells. The top classes of compounds that scored in this screen were corticosteroids and dihydrofolate reductase (DHFR) inhibitors. In addition to modulating the AML1-ETO signature, both classes induced evidence of differentiation, dramatically inhibited cell viability, and ultimately induced apoptosis via on-target activity. Furthermore, AML1-ETO-expressing cell lines were exquisitely sensitive to the effects of corticosteroids on cellular viability compared with nonexpressers. The corticosteroids diminished AML1-ETO protein in AML cells in a proteasome- and glucocorticoid receptor-dependent manner. Moreover, these molecule classes demonstrated synergy in combination with standard AML chemotherapy agents and activity in an orthotopic model of AML1-ETO-positive AML. This work suggests a role for DHFR inhibitors and corticosteroids in treating patients with AML1-ETO-positive disease.
Identification of AML1-ETO modulators by chemical genomics.
Disease, Disease stage, Cell line
View SamplesU937 AML cells that express an inducible AML1-ETO construct under the control of the tetracycline promoter.
Identification of AML1-ETO modulators by chemical genomics.
Cell line
View Samples