Project description:<p>The vasculature represents a highly plastic compartment, capable of switching from a quiescent to an active proliferative state during angiogenesis. Metabolic reprogramming in endothelial cells (ECs) thereby is crucial to cover the increasing cellular energy demand under growth conditions. Here we assess the impact of mitochondrial bioenergetics on neovascularisation, by deleting cox10 gene encoding an assembly factor of cytochrome c oxidase (COX) specifically in mouse ECs, providing a model for vasculature-restricted respiratory deficiency. We show that EC-specific cox10 ablation results in deficient vascular development causing embryonic lethality. In adult mice induction of EC-specific cox10 gene deletion produces no overt phenotype. However, the angiogenic capacity of COX-deficient ECs is severely compromised under energetically demanding conditions, as revealed by significantly delayed wound-healing and impaired tumour growth. We provide genetic evidence for a requirement of mitochondrial respiration in vascular endothelial cells for neoangiogenesis during development, tissue repair and cancer. </p>
Project description:Endothelial differentiation occurs during normal vascular development in the developing embryo. Mouse embryonic stem (ES) cells were used to further define the molecular mechanisms of endothelial differentiation. By flow cytometry a population of VEGF-R2 positive cells was identified as early as 2.5 days after differentiation of ES cells, and a subset of VEGF-R2 + cells, that were CD41+ positive at 3.5 days. A separate population of VEGF-R2+ stem cells expressing the endothelial-specific marker CD144 (VE-cadherin) was also identified at this same time point. Microarray analysis of >45,000 transcripts was performed on RNA obtained from cells expressing VEGF-R2, CD41, and CD144. Keywords: expression analysis
Project description:Embryonic stem (ES) cells have the potential to generate a variety of cell lineages including endothelial cells, blood cells and smooth muscle cells. flk1-expressing cells derived from ES cells serve as vascular progenitors. We have used global gene expression analysis in order to establish a comprehensive list of candidate genes in the developing vasculature during ES cell differentiation in vitro. A large set of genes, including growth factors, cell surface molecules, transcriptional factors, and members of several signal transduction pathways that are known to be involved in vasculogenesis or angiogenesis, were found to have expression patterns as expected. Some unknown or functionally uncharacterized genes were differentially regulated in flk1+ cells compared with flk1 cells, suggesting possible roles for these genes in vascular commitment. Particularly, multiple components of the Wnt signaling pathway were differentially regulated in flk1+ cells, including Wnt proteins, their receptors, downstream transcriptional factors, and other components belonging to this pathway. Activation of the Wnt signal was able to expand vascular progenitor populations whereas suppression of Wnt activity reduced flk1+ populations. Suppression of Wnt signaling also inhibited the formation of matured vascular capillary-like structures during late stages of EB differentiation. These data indicate a requisite and ongoing role for Wnt activity during vascular development, and the gene expression profiles identify candidate components of this pathway that participate in vascular cell differentiation. Keywords: Time course, development, endothelial cell, angiogenesis, embryonic stem cells, mouse, vasculature, Wnt signaling
Project description:Endothelial differentiation occurs during normal vascular development in the developing embryo. Mouse embryonic stem (ES) cells were used to further define the molecular mechanisms of endothelial differentiation. By flow cytometry a population of VEGF-R2 positive cells was identified as early as 2.5 days after differentiation of ES cells, and a subset of VEGF-R2 + cells, that were CD41+ positive at 3.5 days. A separate population of VEGF-R2+ stem cells expressing the endothelial-specific marker CD144 (VE-cadherin) was also identified at this same time point. Microarray analysis of >45,000 transcripts was performed on RNA obtained from cells expressing VEGF-R2, CD41, and CD144. Experiment Overall Design: We identified four populations of cells; cells expressing VEGF-R2 (day 2.5), CD41 expressing cells (day 3.5), cells expressing CD144 (VE-Cadherin, day 3.5), and cells expressing CD144 (day 6.5). In addition to this, we have also obtained the negative control cells at each time such as VEGF-R2 (day 2.5) negative, CD41 negative (day 3.5), CD144 negative (VE-Cadherin, day 3.5), and negative CD144 (day 6.5). RNA for the microarray experiments were obtained in duplicate from two separately conducted experiments using the murine embryonic stem cells..
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.