Abstract 14679: LncRNA SNHG12 Regulates Vascular Senescence and Atherosclerosis by Targeting A DNA-PK-Mediated DNA Damage Response

• Published in: Circulation (New York, N.Y.) Vol. 138; no. Suppl_1 Suppl 1; p. A14679
• Main Authors: Haemmig, Stefan, Yang, Dafeng, Das, Debapria, Ghaffari, Siavash, Deng, Yihuan, Chen, Lei, Sun, Xinghui, Moullan, Norman, Tesmenitsky, Yevgenia, Wara, A.K.M Khyrul, Shvartz, Eugenia, Sukova, Galina, Marto, Jarrod A, Stone, Peter H, Lee, Warren L, Auwerx, Johan, Libby, Peter, Feinberg, Mark W
• Format: Journal Article
• Language: English
• Published: by the American College of Cardiology Foundation and the American Heart Association, Inc 06-11-2018
• ISSN: 0009-7322; 1524-4539

IntroductionNon-coding RNAs have garnered widespread attention as emerging regulators of diverse biological processes. Herein, we identify and validate a unique role for the lncRNA Small Nucleolar Host Gene-12 (SNHG12), in the development of atherosclerosis.MethodsUsing RNA-Seq profiling to identify lncRNAs derived specifically from the aortic intima of LDLR mice during lesion progression and regression phases, we evaluated the role and underlying mechanisms for a top candidate SNHG12, a highly conserved lncRNA across mice, pigs, and humans.ResultsAortic intima expression of SNHG12 was reduced with progression and increased with regression of atherosclerosis. GapmeR-mediated silencing of SNHG12 potently accelerated atherosclerotic lesion formation by 2.4-fold in LDLR mice. Remarkably, the increased lesional effects were not driven by lipid-lowering or by inflammatory recruitment of lesional leukocytes, but rather by increased DNA damage (γH2AX) and senescence (p16, p21, p27) in the vascular endothelium and lesional macrophages. Gain- and loss-of-function studies for SNHG12 demonstrate dynamic regulation of DNA damage and markers of senescence in vitro. SNHG12 deficiency increased transcytosis of LDL by endothelial cells and impaired efferocytosis by macrophages. RNA-IP pulldowns in combination with mass spectrometry showed that SNHG12 interacts with DNA-PK, an important upstream regulator for the DNA damage response (DDR). The absence of SNHG12 reduces DNA-PK’s ability to interact with its binding partner Ku70, abrogating DNA damage repair. DNA-PK silencing blocked the SNHG12-GapmeR-mediated increase of DNA damage in endothelial cells, indicating SNHG12-dependency for DNA-PK. Moreover, rescuing the DDR in vivo, using the anti-DNA damage agent nicotinamide riboside, fully blocked the increase in lesional DNA damage, senescence, atherosclerosis, and plaque necrosis mediated by SNHG12 deficiency. Finally, pig and human atherosclerotic specimens display significantly reduced SNHG12 expression compared to controls that correlated inversely with DNA damage and senescent markers.ConclusionsDeficiency of the lncRNA SNHG12 contributes to impaired DNA damage repair, vascular senescence, and accelerated atherosclerosis independent of lipid-lowering or lesional inflammation. These findings establish a new mechanism by which a lncRNA acting as an RNA-binding protein scaffold interacts with DNA-PK to regulate the DDR in the vessel wall with broad implications for chronic disease states.