Abstract 85: MicroRNA-210 Induces Atherosclerotic Plaque Stability Through Repression of Apoptotic Pathways in Vascular Smooth Muscle Cells

Abstract

Aim of the present study was to explore the role of miRNAs as potential regulators in patients with carotid artery stenosis and concordant vulnerable atherosclerotic plaques. Utilizing patient material from the Biobank of Karolinska Endarterectomies (BiKE), we were able to profile the regulation of miRNAs in patients with symptomatic vs. asymptomatic carotid stenosis undergoing carotid endarterectomy. A PCR-based miRNA array discovered 8 miRNAs (miRs-15b, -29c, -30c/d, -150, -191, -210 and -500) being substantially altered in symptomatic vs. asymptomatic patients. Next we investigated miRNA expression in 2 murine models of vascular injury and plaque vulnerability; balloon injury in Sprague-Dawley rats, and a newly-developed plaque rupture model in ApoE-/- mice, using incomplete ligation of the carotid artery with consecutive cuff injury to induce lesion rupture. In both models miR-210 was significantly repressed in response to vascular injury and plaque instability. In silico analysis revealed 48 previously validated targets of miR-210 in the vasculature. Functional miR-210 modulation analyses in both murine models revealed that the expression of three known tumorsuppressor genes (Aifm3, Apc, Casp8ap2) could be substantially altered through miR-210 modulation, affecting the proliferation rate of smooth muscle cells (SMCs) and plaque stability. By utilizing an in vitro cell streamer system, we subjected human carotid artery endothelial cells (hCAECs) and hCASMCs to laminar and oscillatory flow conditions. Interestingly, laminar flow induced miR-210 up-regulation, whereas turbulent flow suppressed miR-210 expression in both cell lines, suggesting that miR-210 repression in atherosclerotic plaques is a potential result of altered shear stress and accelerated flow patterns. Aifm3, Apc and Casp8ap2 were significantly up-regulated with disturbed flow. The present study explores the role and therapeutic potential of miRNA regulation in patients with vulnerable atherosclerotic lesions, carotid artery stenosis and increased risk of stroke. We were able to identify miR-210 as a key modulator of pathologic processes in atherosclerosis-related vascular remodelling.