MicroRNA-365 promotes the contractile phenotype of venous smooth muscle cells and inhibits neointimal formation in rat vein grafts

The Etiology and Molecular Mechanism Underlying Smooth Muscle Phenotype Switching in Intimal Hyperplasia of Vein Graft and the Regulatory Role of microRNAs

Mounting evidence suggests that the phenotypic transformation of venous smooth muscle cells (SMCs) from differentiated (contractile) to dedifferentiated (proliferative and migratory) phenotypes causes excessive proliferation and further migration to the intima leading to intimal hyperplasia, which represents one of the key pathophysiological mechanisms of vein graft restenosis. In recent years, numerous miRNAs have been identified as specific phenotypic regulators of vascular SMCs (VSMCs), which play a vital role in intimal hyperplasia in vein grafts. The review sought to provide a comprehensive overview of the etiology of intimal hyperplasia, factors affecting the phenotypic transformation of VSMCs in vein graft, and molecular mechanisms of miRNAs involved in SMCs phenotypic modulation in intimal hyperplasia of vein graft reported in recent years.

miR-16-5p Is a Novel Mediator of Venous Smooth Muscle Phenotypic Switching

Vein graft failure after coronary artery bypass grafting (CABG) is primarily caused by intimal hyperplasia, which results from the phenotypic switching of venous smooth muscle cells (SMCs). This study investigates the role and underlying mechanism of miR-16-5p in the phenotypic switching of venous SMCs. In rats, neointimal thickness and area increased over time within 28 days after CABG, as did the time-dependent miR-16-5p downregulation and SMC phenotypic switching. Platelet-derived growth factor-BB-induced miR-16-5p downregulation in HSVSMCs was accompanied by and substantially linked with alterations in phenotypic switching indicators. Furthermore, miR-16-5p overexpression increased SMCs differentiation marker expression while suppressing HSVSMCs proliferation and migration and drastically inhibiting neointimal development in vein grafts. The miR-16-5p inhibited zyxin expression, which was necessary for HSVSMCs phenotypic switching. The miR-16-5p/zyxin axis is a novel, potentially therapeutic target for preventing and treating venous graft intimal hyperplasia.

Upregulation of miR‑423 improves autologous vein graft restenosis via targeting ADAMTS‑7

Coronary artery bypass graft (CABG) is one of the primary methods of treating coronary heart disease (CHD); however, vein graft restenosis is a major limiting factor of the effectiveness of CABG. Emerging evidence has indicated that miR‑423 is associated with vascular diseases. Additionally, upregulation of a disintegrin and metalloproteinase with thrombospondin motifs‑7 (ADAMTS‑7) contributes to neointima formation by promoting the proliferation and migration of vascular smooth muscle cells and inhibiting the proliferation and migration of endothelial cells. The aim of the present study was to examine the effects of miR‑423 target, ADAMTS‑7, on regulating vein graft disease and identify novel biomarkers for use in therapy of vein graft failure (VGF). Aberrant expression of miR‑423 in plasma of patients with CHD prior to and following CABG confirms that miR‑423 may be a suitable target for preventing VGF. Furthermore, a dual‑luciferase reporter gene assay indicated that miR‑423 directly interacted with ADAMTS‑7 and suppressed its expression. Ectopic expression of miR‑423 suppressed ADAMTS‑7, resulting in decreased proliferation and migration rates of human umbilical vein smooth muscle cells by targeting ADAMTS‑7, but resulted in increased proliferation and migration of human umbilical vein endothelial cells in vitro. Overexpression of miR‑423 also enhanced re‑endothelialization and decreased neointimal formation in a rat vein graft model. In conclusion, the results of the present study demonstrated that the miR‑423/ADAMTS‑7 axis may possess potential clinical value for the prevention and treatment of restenosis in patients with CHD following CABG.