Abstract 12138: Cell Senescence Associated H3K9me3 Decline Sensitizes Aortic Valve Cell for Osteogenic Response

Introduction: Cell senescence has been identified as an impact etiological factor in cardiovascular diseases, as well as calcific aortic valve disease (CAVD) . In our previous experiment results, We found that a large number of senescent aortic valve interstitial cells (AVIC) accumulated in the calcific aortic valve tissues, especially around the calcification sites. But the role and mechanism of cellular senescence in the development of calcified aortic stenosis have not been clarified. We hypothesized valvular interstitial cell senescence sensitize interstitial cell for osteogenic response through enhancing cell senescence associated epigenetic modification. Methods and Results: Representative immunofluorescence results of the clinical samples show that p16INK4A positive cells in the calcific aortic valve expressed more osteogenic associated factors, such as Runx2 and BMP2. And RAS system hyperactivation seemed to be an impact association with aortic valve calcification. Then we found Angiotensin II (1μM, 72h) chronic irritation induces valve interstitial cell senescence associated secretion phenotype (SASP) and activates osteogenic response through ERK1/2 and NF-κB pathway. ChIP-qPCR results demonstrated H3K9Me3 modifications on the promoters of Runx2, ACTA2(also known as α-SMA), IL-6, IL-8, MCP-1 were significantly decreased in angiotensin II pretreated AVIC. Blockage of angiotensin II and ABT-263 pretreatment inhibited valvular interstitial cell to convert into osteoblast-like phenotype induced by Angiotensin II, as well as attenuating senescence associated secretion phenotype factors yield. Blockage of angiotensin II receptor and p16 INK4A knockdown contributed to recover H3K9me3 modification on the promoters of those gene in angiotensin II pretreated AVIC through attenuating angiotensin II-induced ubiquitination degradation of SUV39H1. Conclusion: p16 INK4A mediated H3K9me3 decline sensitizes aortic valvular interstitial cell for osteogenic response, which impacts on aortic valve homeostasis and aortic valve calcification. Taken together, p16 INK4A positive senescent cells would be the potential target on prevention and treatment of calcific aortic valve disease.