Involvement of MicroRNA-133a in the Development of Arteriosclerosis Obliterans of the Lower Extremities via RhoA Targeting.

Aim: RhoA is a critical factor in regulating the proliferation and migration of arterial smooth muscle cells (ASMCs) in patients with arteriosclerosis obliterans (ASO). RhoA is modulated by microRNA-133a (miR-133a) in cardiac myocytes and bronchial smooth muscle cells. However, the relationship between miR-133a and RhoA with respect to the onset of ASO in the lower extremities is uncertain.

Methods: We employed in situ hybridization (ISH) and immunohistochemistry (IHC) to detect the location of miR-133a and RhoA in ASO clinical samples, respectively. 5-ethynyl-2'-deoxyuridine (EdU), cell counting kit-8 (CCK-8), Transwell and wound closure assays were utilized to determine the features of human ASMC (HASMC) proliferation and migration. The expression of miR-133a in the HASMCs was assessed using quantitative real-time PCR (qRT-PCR), while that of RhoA was examined via qRT-PCR and Western blotting.

Results: We found miR-133a and RhoA to be primarily located in the ASMCs of ASO. miR-133a was significantly downregulated in the ASO tissues and proliferating HASMCs. In contrast, RhoA was upregulated in the ASO samples. The proliferation and migration of HASMCs was markedly promoted by the downregulation of miR-133a and inhibited by the upregulation of miR-133a. The Luciferase assay confirmed that RhoA was a direct target of miR-133a. The upregulation of miR-133a in the HASMCs decreased the RhoA expression at the protein level. Inversely, the downregulation of miR-133a increased the RhoA protein expression. Of note, the overexpression of RhoA in the HASMCs attenuated the anti-proliferative and anti-migratory effects of miR-133a.

Conclusions: Our data indicate that miR-133a regulates the functions of HASMCs by targeting RhoA and may be involved in the pathogenesis of ASO. These findings may lead to the development of potential therapeutic targets for ASO of the lower extremities.