Many studies have indicated that microRNAs are closely related to the process of peripheral arterial disease (PAD). Previously, we found that microRNA-125a-3p (miR-125a-3p) in restenotic arteries after interventional therapy of lower extremity vessels was notably decreased compared with that of normal control arteries. However, its role in the development of vascular stenosis is not yet clearly understood. The purpose of this study was to investigate the expression, regulatory mechanism and function of miR-125a-3p in the process of vascular stenosis. Methods and results: Quantitative reverse-transcription polymerase chain reaction assays indicated that miR-125a-3p in restenotic arteries after interventional therapy was significantly lower than that in normal control arteries. Immunofluorescence and in situ hybridization co-staining assays in arterial sections demonstrated that miR-125a-3p was mainly expressed in the medial smooth muscle layer. Transfection of miR-125a-3p mimics into cultured vascular smooth muscle cells (VSMCs) effectively inhibited cell proliferation and migration. Then, western blot and luciferase activity assays showed that recombinant human mitogen-activated protein kinase 1 (MAPK1) was a functional target of miR-125a-3p and was involved in miR-125a-3p-mediated cell effects. Finally, the lentiviral infection of miR-125a-3p in balloon-injured rat carotid vascular walls showed that miR-125a-3p overexpression significantly reduced the probability of neointimal membrane production. Conclusions: miR-125a-3p can effectively inhibit the function of VSMCs and the occurrence of vascular stenosis by targeting MAPK1. This study introduces a new molecular mechanism of PAD. We show that regulation of the miR-125a-3p level has the potential to provide a new treatment for PAD and other proliferative vascular diseases. MicroRNAs are highly conserved single-stranded, non-coding RNA

The long non-coding RNA plasmacytoma variant translocation 1 (lncRNA PVT1) has been implicated in the progression of abdominal aortic aneurysms (AAA). However, the detailed mechanism requires further analysis. Our study was aimed at interrogating the mechanism of PVT1 in an H 2 O 2 -induced AAA model in vitro . The expression of lncRNA PVT1, microRNA miR-3127-5p, and NCK-associated protein 1-like (NCKAP1L) was examined in AAA tissues and H 2 O 2 -treated vascular smooth muscle cells (VSMCs). Cell proliferation was assayed using Cell Counting Kit-8 (CCK8) and 5-Bromodeoxyuridine (BrdU) assays. Meanwhile, 5-Ethynyl-2′-deoxyuridine (EdU) staining was performed to assess cell apoptosis and caspase-3 activity. IL-1β and caspase-1 expression was also assessed using Western blotting to determine inflammasome activation in H 2 O 2 -treated VSMCs. Luciferase reporter assays addressed the possible interaction between miR-3127-5p and PVT1 or NCKAP1L, which was predicted by starBase analysis. PVT1 and NCKAP1L expression was elevated in AAA tissues and induced the AAA model in vitro , whereas miR-3127-5p showed the opposite trend. Functionally, PVT1 silencing promoted cell proliferation and reduced the apoptotic rate and inflammasome activation in H 2 O 2 -treated VSMCs. Mechanical investigation demonstrated that PVT1 acted as a sponge of miR-3127-5p to modulate NCKAP1L expression, resulting in suppression of VSMC proliferation, induction of apoptosis, and activation of inflammation. In conclusion, PVT1 participates in AAA progression through the miR-3127-5p/NCKAP1L axis and may be a promising biosignature and therapeutic target for AAA.