Achim LotherInstitute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University of Freiburg, Freiburg, Germany
Lutz HeinInstitute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
Aldosterone is a key factor in adverse cardiovascular remodeling by acting on the mineralocorticoid receptor (MR) in different cell types. Endothelial MR activation mediates hypertrophy, inflammation and fibrosis. Cardiovascular remodeling is often accompanied by impaired angiogenesis, which is a risk factor for the development of heart failure. In this study, we evaluated the impact of MR in endothelial cells on angiogenesis. Deoxycorticosterone acetate (DOCA)-induced hypertension was associated with capillary rarefaction in the heart of WT mice but not of mice with cell type-specific MR deletion in endothelial cells. Consistently, endothelial MR deletion prevented the inhibitory effect of aldosterone on the capillarization of subcutaneously implanted silicon tubes and on capillary sprouting from aortic ring segments. We examined MR-dependent gene expression in cultured endothelial cells by RNA-seq and identified a cluster of differentially regulated genes related to angiogenesis. We found opposing effects on gene expression when comparing activation of the mineralocorticoid receptor in ECs to treatment with vascular endothelial growth factor (VEGF), a potent activator of angiogenesis. In conclusion, we demonstrate here that activation of endothelial cell MR impaired angiogenic capacity and lead to capillary rarefaction in a mouse model of MR-driven hypertension. MR activation opposed VEGF-induced gene expression leading to the dysregulation of angiogenesis-related gene networks in endothelial cells. Our findings underscore the pivotal role of endothelial cell MR in the pathophysiology of hypertension and related heart disease.
Supplemental table S1: Primer sequences
Supplemental table S2: ALDO up- or downregulated genes
Supplemental table S3: MR knockdown up- or downregulated genes
Supplemental Figure S1: Putative MR target genes in endothelial cells. The promoter region (2kb from transcription start site) of ALDO-induced or –repressed genes was screened for enrichment of transcription factor binding motifs (A). mRNA expression of ALDO up- or downregulated genes containing a mineralocorticoid receptor binding motif in their promoter region was derived from RNAseq (B, mean, n =3 per group, *q<0.05, **q<0.01, ***q<0.001).
Supplemental Figure S2: Impact of MR knockdown on gene expression in endothelial cells. We identified biological processes enriched (P<0.01) among genes that were up- or downregulated in solvent- and aldosterone-treated siMR vs. siCTRL (q < 0.05) using ClueGO.
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