miR-145 mediated the role of aspirin in resisting VSMCs proliferation and anti-inflammation through CD40.

Background: Aspirin (ASA) is the most widely used medicine to prevent cardiovascular diseases; however, the mechanisms by which ASA exerts its anti-proliferative effect remain not fully understood. This study was designed to investigate whether miR-145 is involved in the regulation of vascular smooth muscle cells' (VSMCs) proliferation and to determine the anti-inflammatory effects of ASA via its regulation of CD40 to provide a new theoretical basis for the pharmacological effect of aspirin.

Methods: The TNF-α induced proliferation model of VSMCs was divided into different groups with or without aspirin. Cell proliferation was detected by EdU; Real-time PCR was used to detect the mRNA expression of miR-145, CD40, and Calponin, a VSMCs differentiation marker gene. Western blot was used to detect the protein expression of CD40; ELISA was used to determine the concentrations of the inflammatory cytokine IL-6 in cell supernatants.

Results: The proliferation of VSMCs was stimulated by TNF-α and accompanied by decreased levels of Calponin. TNF-α also decreased the levels of miR-145 and increased the levels of CD40 and IL-6. Pretreatment with 20 μg/mL of aspirin in VSMCs could partially block the above-mentioned effects induced by TNF-α. The protective effects of ASA in VSMCs were reversed by a pretreatment with a miR-145 inhibitor. We also found that the expression of miR-145 in peripheral blood mononuclear cells in ischemic stroke patients was significantly increased after a 10-day treatment with aspirin.

Conclusion: miR-145 is involved in the anti-proliferation and anti-inflammation effects of aspirin on VSMCs by inhibiting the expression of CD40.