MicroRNA-142-3p Induces Atherosclerosis-Associated Endothelial Cell Apoptosis by Directly Targeting Rictor

Atherosclerosis, a multifactorial chronic disease, is the main cause of death and impairment in the world. Endothelial cells (ECs) apoptosis plays a crucial role in the onset and development of atherosclerosis, whereas the underlying molecular mechanisms are unclear. MicroRNA-142-3p (miR-142-3p) is a well-defined tumor suppressor in several types of cancer, while the role of miR-142-3p in ECs apoptosis and the development of atherosclerosis has yet to be elucidated. Therefore, the present study aimed to investigate the role of miR-142-3p in ECs apoptosis during atherosclerosis and the underlying mechanism.

Human aortic endothelial cells (HAECs) were treated with oxidized low-density lipoprotein (ox-LDL). The expression level of miR-142-3p was detected using qRT-PCR. Apoptosis was determined via flow cytometry and Caspase-3 activity assay. Prediction of the binding between miR-142-3p and 3'-UTR of Rictor mRNA was performed by bioinformatics analyses and confirmed by a dual luciferase reporter assay. The effects of miR-142-3p on endothelial apoptosis and atherosclerosis were further analyzed in an in vivo model using ApoE-/- mice fed with high-fat diet (HFD).

MiR-142-3p expression was substantially up-regulated during the ox-LDL-elicited apoptosis in HAECs. Forced expression of miR-142-3p exacerbated apoptosis in ECs whereas inhibition of miR-142-3p could partly alleviate apoptotic cell death mediated by ox-LDL. Further analysis identified Rictor as a direct target of miR-142-3p, and Rictor knockdown abolished the anti-apoptotic effect of miR-142-3p inhibitor. Moreover, the Akt/endothelial nitric oxide synthase (eNOS) signaling pathway was found to mediate the beneficial effect of miR-142-3p inhibitor on endothelial apoptosis. Finally, systemic treatment with miR-142-3p antagomir attenuated endothelial apoptosis and retarded the progression of atherosclerosis in the aorta of ApoE-/- mice.

Down-regulation of miR-142-3p inhibited ECs apoptosis and atherosclerotic development by up-regulating the expression of Rictor and activating the Akt/eNOS signaling pathway. This indicates that miR-142-3p may be a potential target for the prevention and treatment of atherosclerosis.