MicroRNA-22-3p Restrains the Proliferation, Phenotypic Transformation, and Migration of Vascular Smooth Muscle Cells by Manipulating TOMM40.

Abstract

microRNA (miR) -22-3p has been confirmed to be engaged in the phenotype transformation and proliferation of vascular smooth muscle cells (VSMCs), which is intimately correlated with restenosis. The current research set out to explore the detailed mechanism and function of miR-22-3p in VSMC proliferation, phenotype transformation, and migration via the translocase of outer mitochondrial membrane (TOMM40). Peripheral blood samples were acquired from patients with in-stent restenosis (ISR) after percutaneous coronary intervention (PCI), with subsequent quantitative reverse transcription (qRT) -polymerase chain reaction (PCR) and Western blot analyses of miR-22-3p and TOMM40 expression. After miR-22-3p-inhibitor, oe-TOMM40, and sh-TOMM40 were transfected into VSMCs, Cell Counting Kit (CCK) -8 assay, scratch test, and Western blot analysis were implemented to measure the VSMC proliferation, migration, and matrix metallopeptidase 9 (MMP9), α-smooth muscle actin (SMA), smooth muscle-myosin heavy chain (SM-MHC), and osteopontin (OPN) expressions, respectively. In addition, human umbilical vein endothelial cell (HUVEC) proliferation was examined by CCK-8 assay. The binding relationship between miR-22-3p and TOMM40 was assessed by dual luciferase reporter and RNA immunoprecipitation assays. The peripheral blood of patients with ISR after PCI had low expression of miR-22-3p and high expression of TOMM40. The mechanistic analysis reported the negative targeting relationship between miR-22-3p and TOMM40. Down-regulating miR-22-3p or up-regulating TOMM40 elevated the proliferation, migration, and phenotype transformation of VSMCs. miR-22-3p inhibitor had no evident impact on HUVEC proliferation. In addition, rescue assays displayed that TOMM40 silencing annulled miR-22-3p inhibition-enhanced VSMC proliferation, migration, and phenotype transformation. Conclusively, miR-22-3p could repress VSMC proliferation, phenotypic transformation, and migration by targeting TOMM40, which might be a possible treatment candidate for restenosis after PCI in patients with cardiovascular disease.