Abstract 12009: Micro-RNA-93 Enhances Endothelial Cell and Myocyte Survival and is a Powerful Inducer of Angiogenesis in Peripheral Arterial Disease
Introduction:MicroRNAs (miRs) are key regulators of gene expression during development and in response to injury, but there is limited knowledge of their role in peripheral arterial disease (PAD). Femoral artery ligation and excision (HLI) in mouse is a widely used pre-clinical model to study PAD. Different in-bred mouse strains show differential response in recovery from HLI. C57Bl/6 (B6) mice recover remarkably well with perfusion reaching ∼80% of its pre-surgical value at 21-days, while BALB/C (BC) mice recover poorly and have increased limb loss. Using this differential phenotypic response to HLI, this study was designed to identify miRs that play a significant role in tissue adaptation to ischemia and adaptive angiogenesis in PAD.
Methods and Results:Comparative miR microarray profiling between BC and B6 mice non-ischemic and ischemic muscle (n=3/group) revealed miR-93 as one of the microRNAs with most consistent difference between the two strains (p<0.0001, >2-fold). Confirmation by real-time-PCR showed that miR-93 increases to∼5-folds at day3 post-HLI, and remains elevated until day10 in B6 mice, but miR-93 does not increase in BC mice (n=5/group). In-vitro, both endothelial cells (HUVEC) and myocytes (C2C12) express miR-93, both up-regulate miR-93 in response to hypoxia and serum starvation. Over-expression of miR-93 in HUVECs promotes cell proliferation, prevents hypoxia-induced apoptosis and enhances tube formation. Knockdown of miR-93 in HUVECs results in increased hypoxia-induced apoptosis and decreased tube formation. The over-expression or knockdown of miR-93 in myocytes results in reduced or increased hypoxia-induced apoptosis, respectively. In-vivo, downregulation of miR-93 in B6 mice decreased perfusion recovery (% non-ischemic leg, day21: Scramble 85.2±2.9 vs. AntagomiR-93 67.9±6). The over-expression of miR-93 in BC mice improved perfusion recovery (%non-ischemic leg, day21: PremiR-93 75±7.5 vs. Scramble 59.6±2.5).
Conclusions: Results from our study show that miR-93 mediates improved functional recovery by enhancing endothelial cell and myocyte survival, and by enhancing angiogenesis. This data suggest that miR-93 may play a role as potential new therapy for PAD.
- © 2012 by American Heart Association, Inc.