Overexpression of MicroRNA-145 Promotes Ascending Aortic Aneurysm Media Remodeling through TGF-β1

ObjectiveIn this study the role of microRNA-145 expression in ascending aortic aneurysm wall media remodeling was examined.MethodsAortic wall samples were obtained from 10 patients who had undergone surgery for ascending aortic aneurysm. Control aortic tissue samples were obtained from 10 patients who had undergone coronary artery bypass graft. The levels of microRNA-145 were analyzed using real time quantitative reverse transcriptase polymerase chain reaction, and western blots were used to determine the expressions of osteopontin (OPN) and collagen. In vitro cultures of vascular smooth muscle cells (VSMCs) were established from both patient groups. The VSMCs were transfected with either microRNA-145 mimics or microRNA-145 inhibitors to determine the effect of microRNA-145 on the expression of OPN and collagen. Furthermore, cells were co-transfected with microRNA-145 mimics and TGF-β1 siRNA to investigate whether TGF-β1 is involved in the process that microRNA-145 increases the expression of OPN and collagen.ResultsAortic microRNA-145, OPN and collagen III was increased in ascending aortic aneurysm patients compared with controls (p < .05). VSMCs transfected with microRNA-145 mimics increased the expression of both OPN (average of 1.59-fold, p < .05) and collagen III (mean of 1.71-fold, p < .05). Cells transfected with microRNA-145 inhibitors decreased expression of both OPN and collagen III compared with negative controls. In addition, the inhibition of TGF-β1 decreased the positive effect of microRNA-145 on the expression of OPN and collagen III.ConclusionThe increased expression of microRNA-145 promotes media remodeling through TGF-β1 in the aortic aneurysm wall.