Sox7 regulates lineage decisions in cardiovascular progenitor cells
Ontology highlight
ABSTRACT: 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:We investigated SOX7 binding events on the chromatin under basal conditions in human umbilical vein endothelial cells, upon overexpression of human SOX7-mCherry and immunoprecipitating mCherry. Cells overexpressing only the mCherry tag were used as negative control condition, and peaks called here were substracted from the SOX7-mCherry peaks.
Project description:Previous studies have demonstrated that distinct progenitor subpopulations of mesoderm display tissue specific and vascular potential: hemangioblasts, a progenitor population capable of generating cells of the hematopoietic, endothelial and vascular smooth muscle lineages, and a multipotential progenitor capable of generating progeny of the cardiac, endothelial and vascular smooth muscle lineages. Each of these populations is characterized by co-expression of brachyury (Bry) and Flk-1, although the hemangioblast population is established before the cardiovascular progenitors in ES cell differentiation cultures (e.g. d3.5 for hemagioblast, versus d4.5 for cardiovascular progenitors). To investigate the role of Notch signalling in the establishment of cardiac lineages, we used a tet-inducible ES cell line (Ainv18) engineered to express an activated form of the Notch4 receptor following doxycycline treatment. This line also expresses a GFP cDNA from the Bry locus. Following 3.0-3.5 days of serum stimulation, three distinct populations based on Flk-1 and GFP expression are observed: Bry-GFP-/Flk-1-, Bry-GFP+/Flk-1- and Bry-GFP+/Flk-1+ cells. Previous studies have shown that the Bry-GFP+/Flk-1+ population contains hemangioblasts, whereas the Bry-GFP+/Flk-1- population displays cardiac potential. Bry-GFP+/Flk-1+ cells, sorted from EB's derived from ES cell differentiation cultures exposed to serum for 3.5 days, were allowed to reaggregate for 24 in the presence or absence of doxycycline, and the total RNA harvested at 4, 12, 24, 48, and 96 hours post Dox induction for microarray analysis. The induced populations were compared to non-induced population harvested at the same time points.
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:To understand the role of Sox7 in primitive endoderm differentiation, we compare the gene expression pattern of Sox7 (+/-) and Sox7 (-/-) ES cells with or without dexamethasome (Dex) treatment. Because these ES cells harbour Gata6-GR transgene, Dex treatment forces ES cells differentate into XEN-like cells. As Sox7 (-/-) ES cells can differentiate into XEN-like cell by morphology, we assessed genome wide gene expression pattern.
Project description:Previous studies have demonstrated that distinct progenitor subpopulations of mesoderm display tissue specific and vascular potential: hemangioblasts, a progenitor population capable of generating cells of the hematopoietic, endothelial and vascular smooth muscle lineages, and a multipotential progenitor capable of generating progeny of the cardiac, endothelial and vascular smooth muscle lineages. Each of these populations is characterized by co-expression of brachyury (Bry) and Flk-1, although the hemangioblast population is established before the cardiovascular progenitors in ES cell differentiation cultures (e.g. d3.5 for hemagioblast, versus d4.5 for cardiovascular progenitors). To investigate the role of Notch signalling in the establishment of cardiac lineages, we used a tet-inducible ES cell line (Ainv18) engineered to express an activated form of the Notch4 receptor following doxycycline treatment. This line also expresses a GFP cDNA from the Bry locus. Following 3.0-3.5 days of serum stimulation, three distinct populations based on Flk-1 and GFP expression are observed: Bry-GFP-/Flk-1-, Bry-GFP+/Flk-1- and Bry-GFP+/Flk-1+ cells. Previous studies have shown that the Bry-GFP+/Flk-1+ population contains hemangioblasts, whereas the Bry-GFP+/Flk-1- population displays cardiac potential.
Project description:To understand the role of Sox7 in primitive endoderm differentiation, we compare the gene expression pattern of Sox7 (+/-) and Sox7 (-/-) ES cells with or without dexamethasome (Dex) treatment. Because these ES cells harbour Gata6-GR transgene, Dex treatment forces ES cells differentate into XEN-like cells. As Sox7 (-/-) ES cells can differentiate into XEN-like cell by morphology, we assessed genome wide gene expression pattern. Sox7 (+/-) ES cells and Sox7 (-/-) ES cells are forced to differentiate into XEN-like cells by Gata6-GR transgene. To compare the gene expression, we collected RNA samples at day4 with or without dexamethasone treatment from each genotype.
Project description:ER71 mutant embryos are nonviable and lack hematopoietic and endothelial lineages. To further define the functional role for ER71 in cell lineage decisions, we generated genetically modified mouse models. We engineered an ER71-EYFP transgenic mouse model by fusing the 3.9 kb ER71 promoter to the EYFP reporter gene. Using FACS and transcriptional profiling, we examined the EYFP+ populations of cells in ER71 mutant and wildtype littermates. In the absence of ER71, we observed an increase in the number of EYFP expressing cells, increased expression of the cardiac molecular program and decreased expression of the hemato-endothelial program compared to the wildtype littermate controls. We have also generated a novel ER71-Cre transgenic mouse model using the same 3.9 kb ER71 promoter. Genetic fate mapping studies revealed that the ER71 expressing cells daughter hematopoietic and endothelial lineages in the wildtype background. In the absence of ER71, these cell populations contributed to alternative mesodermal lineages including the cardiac lineage. To extend these analyses, we used an inducible ES/EB system and observed that ER71 overexpression repressed cardiogenesis. Together, these studies identify ER71 as a critical regulator of mesodermal fate decisions, acting to specify the hematopoietic and endothelial lineages at the expense of cardiac lineages. This enhances our understanding of the mechanisms that govern mesodermal fate decisions early during embryogenesis. 12samples were analyzed, including triplicates of WT; EYFP positive, WT EYFP negative, ER71 MT; EYFP positive and ER71 MT; EYFP negative cells
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:Self-organisation and coordinated morphogenesis of multiple cardiac lineages is essential for the development and function of the heart1-3. However, the absence of a human in vitro model that mimics the basic lineage architecture of the heart hinders research into developmental mechanisms and congenital defects4. Here, we describe the establishment of a reliable, lineage-controlled and high-throughput cardiac organoid platform. We show that cardiac mesoderm derived from human pluripotent stem cells robustly self-organises and differentiates into cardiomyocytes forming a cavity. Co-differentiation of cardiomyocytes and endothelial cells from cardiac mesoderm within these structures is required to form a separate endothelial layer. As in vivo, the epicardium engulfs these cardiac organoids, migrates into the cardiomyocyte layer and differentiates. We use this model to demonstrate that cardiac cavity formation is controlled by a mesodermal WNT-BMP signalling axis. Disruption of one of the key BMP targets in cardiac mesoderm, the transcription factor HAND1, interferes with cavity formation, which is consistent with its role in early heart tube and left chamber development5. Thus, the cardiac organoid platform represents a powerful resource for the quantitative and mechanistic analysis of early human cardiogenesis and defects that are otherwise inaccessible. Beyond understanding congenital heart disease, cardiac organoids provide a foundation for future translational research into human cardiac disorders.