LincRNA‐p21 alleviates atherosclerosis progression through regulating the miR‐221/SIRT1/Pcsk9 axis

Atherosclerosis (AS) is the main aetiology of coronary heart disease, cerebral infarction and peripheral vascular disease in humans. Long‐noncoding RNA (LincRNA)‐p21 has been reported to participate in the development of AS. Therefore, this study was designed to investigate the mechanism of LincRNA‐p21 on suppressing the development of AS. We fed ApoE(−/−) mice with a high‐fat diet to induce an AS mouse model where the lesion area of AS and the extent of lipid deposition were measured. The binding of LincRNA‐p21 and miR‐221 or miR‐221 and SIRT1 was measured using a dual luciferase reporter gene assay and RIP. Following loss‐ and gain‐ function assays, CCK8, EdU, Transwell assay and scratch test were performed to determine the biological processes of human aortic endothelial cells (HAECs). miR‐221 was highly expressed while SIRT1 was poorly expressed in AS. LincRNA‐p21 acted as a sponge for miR‐221. miR‐221 targeted and negatively regulated the expression of SIRT1. LincRNA‐p21 promoted the deacetylation of Pcsk9 by SIRT1 by competitively binding to miR‐221, whereby promoting HAEC proliferation, migration and tube formation. In conclusion, LincRNA‐p21 acted as a molecular sponge for miR‐221 to promote deacetylation of the promoter region of Pcsk9 by SIRT1, therefore preventing the development of AS.