Abstract 646: Locked Nucleic Acid miR-143 Ameliorates Aortic Valve Functions in a ROS-Mediated Murine Model of Aortic Valve Sclerosis

Abstract

Background: Calcific Aortic Valve Disease (CAVD) is the leading cause of valve replacement in the US. While the final stages (Aortic Stenosis -AS) are well described, subclinical stages (Aortic Sclerosis -AVSc) remain understudied. We reported accumulation of Reactive Oxygen Species (ROS) in subclinical stages. Adeno-delivery of antioxidant enzymes rescues Valve Interstitial Cells (VICs) from calcification and osteogenic activation. Furthermore we described OPN-CD44 axis as a calcium-derepression system in AVSc and developed a ROS-mediated murine model based on Angiotensin II infusion that mimic AV remodeling as in AVSc. Here we aim to identify oxidative products able to mediate the transition from AVSc to AS and to test them in vivo. Methods: Oxidized amino-acids were quantified by mass spectrometry (LC MS/MS) on human AVs. Osteogenic-induced VICs and explanted tissues were tested for miR143 expression. C57BL/6J mice were fed an enriched diet and infused with saline (n=24) or AngII (1,000 ng/kg/min) (n=40) for 8 weeks and injected with LNA-miR143 after the first 4 weeks. Echo data were recorded. Results: LC MS/MS revels prdicution of dityrosine in AS only (221±41 μmol/mol), while other oxidized products were undetectable. VICs were then isolated from patients with AVSc and induced to further differentiate into osteogenic VICs by TGF-β1 (10ng/ml for 12 days); In silico target prediction revels miR143 as a possible regulator of CD44. miR143 increases in stimulated cells (4.1 fold vs. untreated, p<0.05) as well as in AV human explants (6.2 fold vs controls, p<0.01). After 8 weeks of Ang II we found sustained activation of VICs (SMA+, OPN+) and ECM remodeling. Mice injected with LNA-miR143 after the development of AV thickening have reduced AV peak gradient, peak velocity, and velocity-time-interval. Conclusions: It is concluded that a) oxidative damage drives the transition between early subclinical stages to calcification and osteogenic differentiation; b) oxidized amino-acid di-tyrosine and miR143 are associated with end-stage diseases c) miR143 mediates the pathological remodeling of the AV in a murine model of subclinical CAVD. Altogether, these data suggest that oxidative damage control VIC activation and AV remodeling via miR143.