The human aortic endothelium undergoes dose-dependent DNA methylation in response to transient hyperglycemia

Glycemic control is a strong predictor of long-term cardiovascular risk in patients with diabetes mellitus, and poor glycemic control influences long-term risk of cardiovascular disease even decades after optimal medical management. This phenomenon, termed glycemic memory, has been proposed to occur due to stable programs of cardiac and endothelial cell gene expression. This transcriptional remodeling has been shown to occur in the vascular endothelium through a yet undefined mechanism of cellular reprogramming. Epigenetics offers a novel mechanism whereby a transient glycemic stress is capable of modifying endothelial susceptibility to the pathological remodeling of cardiovascular disease. In the current study, we show that transient glucose exposure triggers widespread alterations in endothelial DNA methylation which may control several recognized pathological mechanisms of cardiovascular disease, such as the nitric oxide signaling cascade. Future mechanistic studies should therefore investigate the extent to which differential methylation potentiates endothelial dysfunction in response to transient glycemic stress. Whole-genome DNA methylation of human endothelial aortic cells (HAECs) was quantified using reduced-representation bisulfite sequencing (RRBS) following exposure to either diabetic (250 mg/dL) and pre-diabetic (125 mg/dL) concentrations of glucose for 24 hrs (n = 2) relative to vehicle controls. We uncovered a broad genomic distribution of changes in dose-dependent DNA methylation that disproportionately affects the coding region of genes. Among the pathways most affected by differential DNA methylation, “Endothelin Signaling” was found as the most enriched pathway, within which the promoter of Nitric Oxide Synthase 3 (NOS3) was found to be hypo-methylated only upon exposure to diabetic-range glucose concentrations (-20.3%, FDR = 0.0015).