MiR-155-5p Attenuates Vascular Smooth Muscle Cell Oxidative Stress and Migration via Inhibiting BACH1 Expression.

The malfunction of vascular smooth muscle cells (VSMCs) is an initiating factor in the pathogenesis of pathological vascular remodeling, including hypertension-related vascular lesions. MicroRNAs (miRNAs) have been implicated in the pathogenesis of VSMC proliferation and migration in numerous cases of cardiovascular remodeling. The evidence for the regulatory role of miR-155-5p in the development of the cardiovascular system has been emerging. However, it was previously unclear whether miR-155-5p participated in the migration of VSMCs under hypertensive conditions. Thus, we aimed to define the exact role and action of miR-155-5p in VSMC migration by hypertension. Here, we detected that the level of miR-155-5p was lower in primary VSMCs from spontaneously hypertensive rats (SHRs). Its overexpression attenuated, while its depletion accelerated, the migration and oxidative damage of VSMCs from SHRs. Our dual-luciferase reporter assay showed that miRNA-155-5p directly targeted the 3'-untranslated region (3'-UTR) of BTB and CNC homology 1 (BACH1). The miR-155-5p mimic inhibited BACH1 upregulation in SHR VSMCs. By contrast, the deletion of miR-155-5p further elevated the upregulation of BACH1 in SHR-derived VSMCs. Importantly, the overexpression of miR-155-5p and knockdown of BACH1 had synergistic effects on the inhibition of VSMCs in hypertension. Collectively, miR-155-5p attenuates VSMC migration and ameliorates vascular remodeling in SHRs, via suppressing BACH1 expression.