Abstract 892: Ablation of MiR-144 Increases Vimentin Expression and Atherosclerotic Plaque Formation

Objective: It has been suggested that miR-144 is pro-atherosclerotic via effects on reverse cholesterol transportation targeting the ATP binding cassette protein 1 (ABCA1). This study used proteomic analysis to identify additional cardiovascular targets of miR-144, and subsequently examined the role of a newly identified regulator of atherosclerotic burden in miR-144 KO mice receiving a high fat diet (HFD). Approach and Results: To identify affected secretory proteins, miR-144 treated endothelial cell culture medium was subjected to proteomic analysis including two-dimensional gel separation and nanospray liquid chromatography coupled to tandem mass spectrometry. We identified 5 gel spots representing 19 proteins that changed consistently across the biological replicates. One of these spots, was identified as vimentin. Atherosclerosis was induced in miR-144 KO mice by HFD and vascular lesions were quantified by Oil Red-O staining of the serial sectioned aortic root and from en-face views of the aortic tree. Unexpectedly, HFD induced extensive atherosclerosis in miR-144 KO mice in aortic root (WT 100% ± 22.71 vs miR-144 KO 256.88% ± 58.19, p < 0.05, n = 10) and arch areas (WT 100% ± 29.67 vs miR-144 KO 371.74% ± 73.48, p < 0.01, n = 10), and was accompanied by severe fatty liver disease compared with wild type littermates (WT). Vimentin levels were reduced by miR-144 and increased by antagomiR-144 in cultured cardiac endothelial cells without affecting vimentin mRNA levels. Compared with WT, ablation of the miR-144/451 cluster significantly increased plasma vimentin, while vimentin levels were decreased in control mice injected with synthetic miR-144 as double confirmed with Western blot and ELISA assays. Furthermore, increased vimentin expression was seen in the commissural regions of the aortic root (WT 100% ± 10.02 vs 164.19 ± 13.90, p < 0.01, n = 10) and collocated with other areas of aortic atherosclerosis. In contrast, neither liver ABCA1 nor circulating cholesterol levels were different between WT and miR-144/451 KO mice. Conclusion: We conclude that miR-144 is a potential regulator of the development of atherosclerosis via changes in vimentin signaling and both miR-144 and vimentin are potential therapeutic targets for atherosclerosis.