MiR-126 regulates the effect of mesenchymal stem cell vascular repair on carotid atherosclerosis through MAPK/ERK signaling pathway.

BACKGROUND: Carotid atherosclerosis is a complex disease involving multiple cellular and molecular pathways. Mesenchymal stem cells (MSCs) show therapeutic potential, but their optimal targets and efficacy are still under study. MiR-126 enhances endothelial function and promotes angiogenesis by relieving vascular endothelial growth factor signaling suppression, suggesting its potential in vascular regeneration. However, its role in directing stem cell differentiation toward endothelial lineages remains unclear. We hypothesize that miR-126 may influence MSCs' immunomodulatory and vascular reparative functions via the mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/ERK) pathway, thereby improving carotid atherosclerosis. This study explores this mechanism to provide novel insights and support the development of miR-126-based therapeutic strategies. AIM: To verify if miR-126 inhibits carotid atherosclerosis via the MAPK/ERK pathway. METHODS: Rat bone marrow MSCs (product No. CP-R131, Wuhan, China) were verified by flow cytometry. The effects of miR-126 on MSCs' proliferation, migration, apoptosis, and cytokine expression were explored using microRNA mimics and inhibitors. Fluorescence staining quantified CD31+ cells to evaluate endothelial differentiation. In vivo differentiation was assessed, and MSCs were transplanted into a rat carotid artery balloon dilatation model. Rats were randomly divided into five groups: Control, negative control mimics, miR-126 mimics, negative control inhibitor, and miR-126 inhibitor. RESULTS: In vitro, MSCs treated with miR-126 mimics demonstrated enhanced proliferation, increased migration, and reduced apoptosis. These miR-126 mimics also significantly increased the secretion of vascular endothelial growth factor and basic fibroblast growth factor. Fluorescence and tissue staining indicated a higher proportion of CD31+ cells in the miR-126 mimics group. Additionally, the expression of endothelial-related genes (von Willebrand factor, endothelial nitric oxide synthase, and vascular endothelial-cadherin) was upregulated in this group. In vivo, miR-126-transfected MSCs effectively reduced neointimal thickness and promoted endothelial coverage in rats. MiR-126 stimulated MSC proliferation in a dose-dependent manner and reduced p38 and ERK1/2 phosphorylation. Conversely, miR-126 inhibition or blank controls resulted in opposing effects. CONCLUSION: MiR-126 exerts significant modulatory effects on the immunoregulatory and vascular reparative functions of MSCs through the MAPK/ERK signaling pathway, promoting their differentiation into endothelial cells and thereby mitigating atherosclerosis.