A Novel Angiotensin II Induced Long Non‐coding RNA GIVER Regulates Oxidative Stress, Inflammation, and Proliferation in Vascular Smooth Muscle Cells

Abstract

Angiotensin II (Ang II)‐mediated vascular smooth muscle cell (VSMC) dysfunction plays a major role in the pathogenesis of hypertension. Long non‐coding RNAs (lncRNAs) have recently elicited much interest, but their roles in Ang II actions and hypertension are not well understood. We aim to investigate the regulation and functions of a novel lncRNA “Growth factor‐ and pro‐Inflammatory cytokine‐induced Vascular cell‐Expressed lncRNA (Giver)”, in Ang II‐mediated VSMC dysfunction. RNA‐seq and RT‐qPCR analyses revealed that Ang II stimulation of rat VSMC increased expression of Giver, and Nr4a3, an adjacent gene which encodes a nuclear receptor. Similar changes were observed in rat and mouse aortas treated ex vivo with Ang II. Giver and Nr4a3 were also significantly induced by key mitogenic and pro‐inflammatory stimuli. RNA‐FISH and nuclear fractionations showed that Giver is localized predominantly in the nucleus. Regulation of Giver promoter in response to Ang II occurs through the binding of Nr4a3 to a consensus NBRE binding site. In vitro RNA pull down assays using biotinylated Giver combined with mass spectrometry in VSMC showed that Giver interacts with nuclear and chromatin remodeling related factors like ruvB‐like1, WD repeat‐containing protein 82, histone‐binding protein RBBP7, non‐POU domain‐containing octamer‐binding protein and other RNA binding proteins involved in splicing and RNA processing. Furthermore, microarray profiling combined with RT‐qPCR validation revealed that Giver knockdown attenuates the expression of genes involved in oxidative stress (Nox1) and inflammatation (Il6, Ccl2, and Tnf), but increases Nr4a3, in VSMC. Conversely, Giver overexpression enhanced the expression of these genes. Accordingly, Giver knockdown also inhibited Ang II‐induced oxidative stress and proliferation. Moreover, Giver overexpression in VSMC enhanced enrichment of Pol lI but decreased repressive histone modification H3K27me3 at oxidative stress and inflammatory gene promoters. Human orthologous genes GIVER and NR4A3 were also induced by Ang II in human VSMC and endothelial cells. Interestingly, GIVER and NR4A3 were also increased in arteries from hypertensive patients, but attenuated in hypertensive patients treated with Angiotensin Converting Enzyme Inhibitors or Angiotensin Receptor Blockers. Thus, LncRNA Giver and its regulator Nr4a3 are important players in Ang II‐mediated VSMC dysfunction, and can serve as novel targets for anti‐hypertensive therapy.Support or Funding InformationNIH, NHLBIThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.