Downregulation of miR-34a promotes endothelial cell growth and suppresses apoptosis in atherosclerosis by regulating Bcl-2

• Published in: Heart and vessels 2018-10, Vol.33 (10), p.1185-1194
• Main Authors: Su, Gang, Sun, Guangli, Liu, Hai, Shu, Liliang, Liang, Zhenxing
• Format: Article
• Language: English
• Subjects: 3' Untranslated regions; Aortic arch; Apolipoprotein E; Apoptosis; Arteriosclerosis; Atherosclerosis; Bcl-2 protein; Biomedical Engineering and Bioengineering; Cardiac Surgery; Cardiology; CD31 antigen; Cell cycle; Cell growth; Cholecystokinin; Cytometry; Endothelial cells; Flow cytometry; Gene expression; High fat diet; Immunoprecipitation; Lesions; Low density lipoprotein; Medicine; Medicine & Public Health; Mice; Oils & fats; Original Article; Ribonucleic acid; RNA; Target recognition; Vascular Surgery
• ISSN: 0910-8327; 1615-2573
• DOI: 10.1007/s00380-018-1169-6

Several miRNAs have been demonstrated to be involved in endothelial dysfunction during atherosclerosis (AS). However, the detailed roles and underlying mechanisms of miR-34a in AS-associated endothelial cell apoptosis are far from being addressed. Apolipoprotein E-deficient (ApoE −/− ) mice fed with high-fat diet (HFD) were used as in vivo model of AS. Oxidized low-density lipoprotein (ox-LDL)-treated human aortic endothelial cells (HAECs) were applied as in vitro model of AS. The effects of miR-34a on atherosclerotic lesions were evaluated by hematoxylin–eosin (HE) and Oil Red O staining. Pecam-1 + endothelial cells were isolated from the aortic arch with flow cytometry. qRT-PCR and western blot were employed to measure gene and protein expression. The effects of miR-34a on cell viability, cell cycle distribution, and apoptosis were assessed by Cell counting kit (CCK)-8 and flow cytometry analysis. The relationship between miR-34a and Bcl-2 was confirmed by online softwares, luciferase reporter assay, and RNA immunoprecipitation (RIP). miR-34a was upregulated in HFD-induced ApoE −/− mice and ox-LDL-treated HAECs. Anti-miR-34a decreased atherosclerotic lesions and inhibited Pecam-1 + endothelial cells apoptosis in HFD-induced ApoE −/− mice. Moreover, anti-miR-34a significantly promoted cell viability, alleviated cell cycle arrest, and restrained apoptosis in ox-LDL-treated HAECs. Furthermore, Bcl-2 was identified as a target of miR-34a, and miR-34a inhibited Bcl-2 expression via binding to its 3′UTR. Rescue experiments demonstrated that Bcl-2 overexpression dramatically reversed miR-34a-mediated inhibition of cell growth and promotion of apoptosis in ox-LDL-exposed HAECs. Depletion of miR-34a facilitated endothelial cell growth and blocked apoptosis in AS by upregulating Bcl-2, offering a promising avenue for AS therapy.