Flow-dependent epigenetic DNA methylation regulates endothelial gene expression and atherosclerosis
Jessilyn Dunn, … , I. King Jordan, Hanjoong Jo
Jessilyn Dunn, … , I. King Jordan, Hanjoong Jo
Published May 27, 2014
Citation Information: J Clin Invest. 2014;124(7):3187-3199. https://doi.org/10.1172/JCI74792.
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Research Article Vascular biology

Flow-dependent epigenetic DNA methylation regulates endothelial gene expression and atherosclerosis

Abstract

In atherosclerosis, plaques preferentially develop in arterial regions of disturbed blood flow (d-flow), which alters endothelial gene expression and function. Here, we determined that d-flow regulates genome-wide DNA methylation patterns in a DNA methyltransferase–dependent (DNMT-dependent) manner. Induction of d-flow by partial carotid ligation surgery in a murine model induced DNMT1 in arterial endothelium. In cultured endothelial cells, DNMT1 was enhanced by oscillatory shear stress (OS), and reduction of DNMT with either the inhibitor 5-aza-2′-deoxycytidine (5Aza) or siRNA markedly reduced OS-induced endothelial inflammation. Moreover, administration of 5Aza reduced lesion formation in 2 mouse models of atherosclerosis. Using both reduced representation bisulfite sequencing (RRBS) and microarray, we determined that d-flow in the carotid artery resulted in hypermethylation within the promoters of 11 mechanosensitive genes and that 5Aza treatment restored normal methylation patterns. Of the identified genes, HoxA5 and Klf3 encode transcription factors that contain cAMP response elements, suggesting that the methylation status of these loci could serve as a mechanosensitive master switch in gene expression. Together, our results demonstrate that d-flow controls epigenomic DNA methylation patterns in a DNMT-dependent manner, which in turn alters endothelial gene expression and induces atherosclerosis.

Authors

Jessilyn Dunn, Haiwei Qiu, Soyeon Kim, Daudi Jjingo, Ryan Hoffman, Chan Woo Kim, Inhwan Jang, Dong Ju Son, Daniel Kim, Chenyi Pan, Yuhong Fan, I. King Jordan, Hanjoong Jo

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Figure 7

D-flow induces DNA hypermethylation of the HoxA5 gene promoter and downregulates its expression in a 5Aza-dependent manner.

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D-flow induces DNA hypermethylation of the HoxA5 gene promoter and downr...
(A) DNA methylation at the HoxA5 promoter region in endothelial-enriched genomic DNA from the LCA and RCA at 1 week after partial ligation from mice treated with saline or 5Aza was further examined in independent samples by bisulfite sequencing. Black and white circles represent methylated and unmethylated cytosines, respectively. Eight CG sites (denoted by the columns) were probed in this assay, and 8 to 10 colonies (denoted by the rows) were chosen for analysis. Percentages below the figures denote the average percent methylation for this region of the HoxA5 promoter. (B and C) HoxA5 gene expression was examined in endothelial-enriched RNA from the LCA and RCA obtained at 1 week after partial ligation from saline- or 5Aza-treated mice by microarray analysis. Data for B are shown as the mean ± SEM. **P < 0.01, n = 3 each and were validated by qPCR. Data for C are shown as the mean ± SEM. **P < 0.01, n = 5 each.