RESUMO
Proximal promoter DNA methylation has been shown to be important for regulating gene expression. However, its relative contribution to the cell-specific expression of endothelial cell (EC)-enriched genes has not been defined. We used methyl-DNA immunoprecipitation and bisulfite conversion to analyze the DNA methylation profile of EC-enriched genes in ECs vs nonexpressing cell types, both in vitro and in vivo. We show that prototypic EC-enriched genes exhibit functional differential patterns of DNA methylation in proximal promoter regions of most (eg, CD31, von Willebrand factor [vWF], VE-cadherin, and intercellular adhesion molecule-2), but not all (eg, VEGFR-1 and VEGFR-2), EC-enriched genes. Comparable findings were evident in cultured ECs, human blood origin ECs, and murine aortic ECs. Promoter-reporter episomal transfection assays for endothelial nitric oxide synthase, VE-cadherin, and vWF indicated functional promoter activity in cell types where the native gene was not active. Inhibition of DNA methyltransferase activity indicated important functional relevance. Importantly, profiling DNA replication timing patterns indicated that EC-enriched gene promoters with differentially methylated regions replicate early in S-phase in both expressing and nonexpressing cell types. Collectively, these studies highlight the functional importance of promoter DNA methylation in controlling vascular EC gene expression.
Assuntos
Metilação de DNA , Período de Replicação do DNA , Endotélio Vascular/citologia , Regulação da Expressão Gênica , Regiões Promotoras Genéticas/genética , Fase S/fisiologia , Animais , Antígenos CD/genética , Aorta/citologia , Aorta/metabolismo , Caderinas/genética , Bovinos , Moléculas de Adesão Celular/genética , Células Cultivadas , Imunoprecipitação da Cromatina , Derme/citologia , Derme/metabolismo , Endotélio Vascular/metabolismo , Hepatócitos/citologia , Hepatócitos/metabolismo , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Queratinócitos/citologia , Queratinócitos/metabolismo , Camundongos , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , Óxido Nítrico Sintase Tipo III/genética , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Fator de von Willebrand/genéticaRESUMO
PURPOSE OF REVIEW: To provide an overview of the biological processes implicated in chromatin-based pathways that control endothelial gene expression patterns in both health and disease and highlight how these processes are relevant to cardiovascular disease. RECENT FINDINGS: Epigenetics refers to chromatin-based pathways important in the regulation of gene expression and includes three distinct, but highly interrelated, mechanisms: DNA methylation, histone density and posttranslational modifications, and RNA-based mechanisms. It is of great interest that epigenetic regulation of genes enriched in the vascular endothelium is a prominent regulatory pathway. How environmental cues within the vasculature, such as hemodynamic forces or hypoxia, influence these epigenetic mechanisms will be reviewed. SUMMARY: Although a newer area for study, exciting new evidence identifies that epigenetic processes are highly dynamic and respond to a myriad of environmental stimuli. Integrating chromatin-based pathways into our understanding of gene expression offers newer insight into disease processes.