Project description:Vascular development involves complex changes in gene expression necessary to dictate the behaviour of differentiating endothelial cells within the emerging vascular network. However, the transcriptional programs regulating vascular development are poorly understood. Here we use a DamID approach to profile for the first time the global DNA binding pattern of SOX7, FLI1 and ERG in endothelial precursor cells. We uncover that SOX7, FLI1 and ERG bind together at endothelial specific regulatory regions to drive a transcriptional program important for vascular development.
Project description:Vascular development involves complex changes in gene expression necessary to dictate the behaviour of differentiating endothelial cells within the emerging vascular network. However, the transcriptional programs regulating vascular development are poorly understood. Here we use a microarray approach to profile the genes regulated in response to SOX7 overexpression.
Project description:Although differentiation of mice embryonic stem cells into vascular endothelial cells (ECs) gives a model for investigating molecular mechanisms of vascular development in vivo, temporal dynamics of gene expressions and chromatin modifications have not been studied until now. Here, we interrogated transcriptome and two histone modifications, H3K4me3 and H3K27me3, with a genome-wide scale during ECs differentiation and elucidated epigenetic switch peculiar to ECs. We find Gata2, Fli1, Sox7, and Sox18 are master regulators from genetic and epigenetic data, these genes were induced after Etv2 activation. These genes have specific histone modification pattern which is repressed by H3K27me3 modification at Flk-sorted mesoderm and changed to the bivalent (H3K4me3 and H3K27me3 both positive) state rapidly after vascular endothelial cells growth factor (VEGF) stimuli. Using a previously reported ECs differentiation model, we demonstrate that four transcription factors are critical for ECs specific gene expressions and efficient differentiation. Moreover, from knockdown experiments using si-RNA, we discovered these factors inhibited not only TGFβ signaling pathway, that is endothelial mesenchymal transition pathway, but also other near lineage commitment, including blood cells, skeletal muscle cells, vascular smooth muscle cells, and cardiomyocytes. We further identify each factor specific target genes during ECs differentiation by microarray, including both activating and repressing genes. Together, our findings from a detailed epigenetic approach provide a basic understanding temporal regulated chromatin signatures and resulting gene expression profile during ECs commitment, which is applicable to other models of differentiation and production of mature and long lasting ECs for regenerative medicine. Total 17 samples were derived from [1] ES cells, Flk-sorted mesoderm cells, and in the absense or presence of VEGF (6, 12, 24, and 48h) to determine VEGF activated genes during endothelial cells differentiation, [2] control si-RNA, si-Gata2, si-Fli1, si-Sox7, or si-Sox18 transfected cells under VEGF stimuli, [3] control si-RNA or si-Mix (si-Gata2, si-Fli1, si-Sox7, and si-Sox18) transfected cells under VEGF stimuli for the identification of each transcription factor dependent genes during endothelial cells differentiation.
Project description:We discover that ER71/ETV2 initiates hemangiogenic program by activating blood and endothelial cell lineage specifying genes while enhancing FLK1 expression and expanding hemangioblast population. Furthermore, ER71/ETV2 establishes an ETS hierarchy by directly activating Ets genes in hematopoietic and endothelial cell lineage development. As such, ER71/ETV2-initiated blood and endothelial cell program is maintained by ER71/ETV2 downstream ETS factors through an ETS switching mechanism. ChIP-seq analysis of ER71 in differentiated embryonic stem cells
Project description:We discover that ER71/ETV2 initiates hemangiogenic program by activating blood and endothelial cell lineage specifying genes while enhancing FLK1 expression and expanding hemangioblast population. Furthermore, ER71/ETV2 establishes an ETS hierarchy by directly activating Ets genes in hematopoietic and endothelial cell lineage development. As such, ER71/ETV2-initiated blood and endothelial cell program is maintained by ER71/ETV2 downstream ETS factors through an ETS switching mechanism.
Project description:Glioblastoma multiforme (GBM) is a highly aggressive and vascularized malignant brain tumor. SoxF transcription factors consisting of Sox7, Sox17, and Sox18 are expressed specifically in endothelial cells (ECs) and contribute to vascular morphogenesis. While the role of Sox17 was found in subcutaneous ectopic tumors, Sox7 has not been studied in the context of tumor angiogenesis. Here, we investigated gene expression profile of RNA analysis of Sox7- and Sox17-deficient mouse endothelial cells from high grade glioma using RNA sequencing to validate molecular characteristics of Sox7 and Sox17 in high grade glioma.
Project description:In vertebrates, lifelong supply of all the blood cell types in suitable numbers is maintained by the hematopoietic stem cells (HSCs). During development, these HSCs emerge in the aorta-gonad-mesonephros (AGM) from specialized vascular endothelium through a transdifferentiation process, called as endothelial-to-hematopoietic transition (EHT). During this process, select endothelial cells (CD31+c-kit- or CD31PCKITN) switch to a hematopoietic transcriptional program, undergo morphological changes and become hemogenic (CD31+c-kit+ or CD31PCKITP) and gives rise to hematopoietic cells (CD31-c-kit+ or CD31NCKITP). A complex interplay of key transcription factors and signaling pathways coordinates the whole process. Specific metabolic signature of a cell can precisely define its phenotype. Evidence has emerged that cellular phenotype and function can be driven according to the changes in cellular metabolism. Metabolic programs, which are stage specific, allow stem cells to adapt their function in different microenvironments. In the present study, we performed nano LC-MS/MS based proteomic analysis to understand the molecular program involved in the transdifferentiation of endothelial to hematopoietic cells.
Project description:Specification of the mesodermal lineages requires a complex set of morphogenetic events orchestrated by interconnected signaling pathways and gene regulatory networks. The transcription factor Sox7 has critical functions in differentiation of multiple mesodermal lineages, including cardiac, endothelial, and hematopoietic. Using a doxycycline-inducible mouse embryonic stem cell (mESC) line, we have previously shown that expression of Sox7 in cardiovascular progenitor cells promotes expansion of endothelial progenitor cells. Here, we show that the ability of Sox7 to promote endothelial cell fate occurs at the expense of the cardiac lineage. Using ChIP-Seq coupled with ATAC-Seq we identify downstream target genes of Sox7 in cardiovascular progenitor cells and, by integrating these data with transcriptomic analyses, we define Sox7-dependent gene programs specific to cardiac and endothelial progenitor cells. Further, we demonstrate a protein-protein interaction between SOX7 and GATA4 and provide evidence that Sox7 interferes with the transcriptional activity of Gata4 on cardiac genes. In addition, we show Sox7 modulates WNT and BMP signaling during cardiovascular differentiation. Our data represent the first genome-wide analysis of Sox7 function and reveal a critical role for Sox7 in regulating signaling pathways that affect cardiovascular progenitor cell differentiation.
Project description:The molecular mechanisms regulating endothelial to hematopoietic transition (EHT) of hemogenic endothelium (HE) are poorly understood. Here we profile the transcriptional changes resulting from SOX7 overexpression during EHT