Abstract 106: Prevention of Abdominal Aortic Aneurysm by Anti-MiRNA-712 or Anti-miR-205 in Angiotensin II--Infused Mice

Abstract

Abdominal aortic aneurysm (AAA) is characterized by weakening of the vessel wall, followed by progressive expansion of the diseased aortic segment. MicroRNAs (miRNAs) have emerged as key regulator of gene expression in the cardiovascular diseases and may play a key role in therapeutically targeting AAA development. Although,vascular wall degradation by matrix metalloproteases (MMPs) is the key mechanism in AAA development, their targeting through miRNAs have never been studied. We identified microRNA-712 (miR-712) as a novel Angiotensin II(AngII)-sensitive miRNA which is upregulated in the abdominal aortic endothelium of AngII-infused mice. Mechanistically, we identified that miR-712 directly regulates two key endogenous inhibitors of MMP: tissue inhibitor of metalloproteinase 3 (TIMP3) and reversion inducing cysteine-rich protein with kazal motifs (RECK). Furthermore, inhibition of miR-712 by subcutaneous injection of anti-miR-712 significantly decreased MMP activity in the AngII-infused abdominal aorta wall, prevented the dilatation of aortae and significantly reduced AAA incidence from 80% (8/10) to 20% (2/10), compared to its mismatched control in ApoE -/- mice. Interestingly, based on the seeding sequence, we identified miR-205 as the human homolog of miR-712. miR-205 was also upregulated by AngII treatment and like miR-712 regulated MMPs activity via TIMP3 and RECK. Moreover, inhibition of miR-205 dramatically inhibits AngII-induced AAA development. We also found that miR-205 was significantly upregulated in the aortic sections of AAA patients in comparison to the healthy controls. Our findings demonstrate that AngII-sensitive miRNAs, miR-712 and miR-205, regulate MMP activity through TIMP3 and RECK and play important role in the pathogenesis of AAA. These results suggest that targeting these miRNAs using their inhibitors may hold promise as a therapeutic strategy to prevent the development of AAA.