Studies in CRISPR-generated Mediterranean G6PD variant rats reveal G6PD orchestrates genome-wide DNA methylation and gene expression in vascular wall

Abstract

AbstractBackgroundRecent advances have revealed the importance of epigenetic modifications to gene regulation and transcriptional activity. DNA methylation, a determinant of genetic imprinting andde novosilencing of genes genome-wide, is known to be controlled by DNA methyltransferases (DNMT) and demethylases (TET) under disease conditions. However, the mechanism(s)/factor(s) influencing the expression and activity of DNMTs and TETs, and thus DNA methylation, in healthy vascular tissue is incompletely understood. Based on our recent studies, we hypothesized that glucose-6-phosphate dehydrogenase (G6PD) is a modifier of DNMT and TET expression and activity and an enabler of gene expression.MethodsIn aorta of CRISPR-edited rats with the Mediterranean G6PD variant we determined DNA methylation by whole-genome bisulfite sequencing, gene expression by RNA sequencing, and large artery stiffness by echocardiography.ResultsHere, we documented higher expression ofDnmt3a, Tet2, andTet3in aortas from Mediterranean G6PDS188Fvariant (a loss-of-function single nucleotide polymorphism) rats than their wild-type littermates. Concomitantly, we identified 17,618 differentially methylated loci genome-wide (5,787 hypermethylated loci, including down-regulated genes encoding inflammation- and vasoconstriction-causing proteins, and 11,827 hypomethylated loci, including up-regulated genes encoding smooth muscle cell differentiation- and fatty acid metabolism-promoting proteins) in aorta from G6PDS188Fas compared to wild-type rats. Further, we observed less large artery (aorta) stiffness in G6PDS188Fas compared to wild-type rats.ConclusionsThese results establish a noncanonical function of the wild-type G6PD and G6PDS188Fvariant in the regulation of DNA methylation and gene expression in healthy vascular tissue and reveals G6PDS188Fvariant contributes to reduce large artery stiffness.HighlightsThe wild-type G6PD and G6PDS188Fvariant regulates the expression and activity of nuclear DNMT and TET and selectively evokes hyper/hypo-methylation of loci/promoter regions genome-wide.G6PDS188Fvariant represses and activates genes detrimental and beneficial to vascular cell phenotype and function, respectively.G6PDS188Fvariant reduces large artery stiffness.