Rapamycin attenuates a murine model of thoracic aortic aneurysm by downregulating the miR-126–3p mediated activation of MAPK/ERK signalling pathway

Thoracic aortic aneurysm (TAA) is fatal diseases, which leads to aortic rupture and sudden death. Blood pressure-lowering drugs are ineffective for most of the patients. Our previous study demonstrated the inhibition of endothelial secreted miR-126e3p by rapamycin ameliorate the aneurysmal phenotype of smooth muscle cells (SMCs) in vitro. Hence, this study aimed to evaluate the modulation and mechanism of miR-126e3p in a murine model of TAA (Fbn1C1039G/þ). Our results showed that noticeable disturbed flow (DF) was observed in the aorta of Fbn1C1039G/þ mice, and the expression of miR-126e3p was significantly increased under the DF in the cell chamber. This finding was also confirmed by tests in the corresponding DF area of the human aortic aneurysm tissue. Constant rapamycin administration significantly ameliorates the incidence and severity of Fbn1C1039G/þ mice characterized by decreased aortic media degradation, macrophage infiltration and MMP2/9 expression in the aortic wall. Mecha- nistic studies showed that rapamycin attenuates TAA progression by inhibiting miR-126e3p through ERK1/2 inactivation.