Abstract 13466: In Experimental Pad miR29a Modulates Perfusion Recovery and ADAM12 Expression Through Direct Interaction With ADAM12 mRNA

Abstract

Peripheral artery disease (PAD) is caused by atherosclerotic occlusion of vessels outside the heart and most commonly affects vessels of the lower extremities. Angiogenesis is a part of the post ischemic adaption involved in restoring blood flow in PAD. Previously, in a murine hind limb ischemia (HLI) model of PAD, we identified ADAM12 as a key genetic modifier of post-ischemic perfusion recovery. However, less is known about ADAM12 regulation in ischemia. MiRNAs are a class of small, non-coding, single-stranded RNAs that regulate gene expression primarily through transcriptional repression of mRNA. We showed miR29a modulates ADAM12 expression in the setting of type 1 DM and ischemia. However, how miR29a modulates ADAM12 was not known. Moreover, the physiological effects of miR29a modulation in a non-diabetic setting was not known. Here, we demonstrate that AAV-mediated ectopic overexpression of miR29a in ischemic mouse hind limbs impairs post ischemic perfusion recovery and angiogenesis. We further demonstrate that miR29a regulates ADAM12 through direct interaction with ADAM12 mRNA. Treatment of ischemic mouse hind limbs with AAV9 particles containing miR29a (pAV-miR29a) increased miR29a expression (pAV-control vs pAV-miR29a: 3.22 ± 0.36, vs 1.0 ± 0.09, p<0.05, n=5-6,) and decreased ADAM12 mRNA expression (1.0 ± 0.31 vs 0.30 ± 0.08, p<0.05, n=7-10) resulting in decreased angiogenesis (1.0 ± 0.07 vs 0.66 ± 0.04, p<0.05, n=5), and impairment perfusion (week 3 post HLI perfusion, 101.9±5.55 vs 66.13±12.39, p<0.05, n=5-6,).AGO2 miRNA/RNA-immunoprecipitation studies showed levels of miR29a and ADAM12 mRNA in the complex decreased in samples treated with antagomiR29a (4, 40, 400nM) in a dose dependent manner (miR29a: 0.87, 0.68, 0.44, and ADAM12: 0.89, 0.78, 0.67, fold) but was unchanged by control antagomir (miR29a: 0.84, 0.84, 0.87, fold, and ADAM12: 1.11, 1.12, 1.10, fold). Taken together the data shows miR29a suppresses ADAM12 expression by directly binding to its mRNA resulting in impaired angiogenesis and poor perfusion. Hence, elevated levels of miR29a as seen in diabetes likely contributes to vascular pathology and lowering miR29a could be a therapeutic target.