Extensive inflammation of endothelial cells (ECs) facilitates atherosclerotic lesion formation. Circular RNA (circRNA) participates in atherosclerosis (AS)-related inflammation responses; however, whether and how circ_0086296 regulates atherosclerotic inflammation and lesions have not been investigated. Microarray analysis, quantitative real-time polymerase chain reaction, and fluorescence in situ hybridization assay were performed to detect the expression and location of hsa_circ_0086296 in human carotid artery plaques, aorta of atherosclerotic mice, and human umbilical vein endothelial cells (HUVECs). Sanger sequencing was used to verify the loop structure of circ_0086296. The relationship among circ_0086296, miR-576-3p, IFIT1, STAT1, and EIF4A3 was validated using bioinformatics, luciferase assay, RNA pull-down assay, and RNA immunoprecipitation. The atherosclerosis mouse model was used to evaluate the function of circ_0086296 in vivo. circ_0086296 expression was significantly upregulated in human carotid artery plaques, oxidized low-density lipoprotein (ox-LDL)-treated HUVECs, and the aorta of atherosclerotic mice. Functional analysis indicated that circ_0086296 promotes ECs injury in vitro and atherosclerosis progression in vivo. The mechanism analysis indicated that circ_0086296 sponged miR-576-3p to promote IFIT1–STAT1 expression. Moreover, STAT1 upregulated circ_0086296 expression, forming the circ_0086296/miR-576-3p/IFIT1/STAT1 feedback loop. Notably, inhibition of the circ_0086296/miR-576-3p/IFIT1 axis could block atherosclerotic lesion formation both in vivo and in vitro. Finally, circ_0086296 was overexpressed in exosomes of patients with atherosclerosis and exosomes of ox-LDL-treated ECs. Therefore, the circ_0086296/miR-576-3p/IFIT1/STAT1 feedback loop participates in atherosclerosis progression and contributes to the high circ_0086296 expression observed in the exosomes of serum of patients with atherosclerosis. This study sought to provide a deep understanding of the mechanisms underlying the aberrant EC phenotype in AS.

Endothelial cell (EC) dysfunction induces atherosclerotic coronary heart disease (CHD) development. Recent studies demonstrated that lncRNA NEAT1 mediates multiple biological functions of cells. How NEAT1 regulates EC function is still unclear, so this study explored the role and mechanism of NEAT1 in oxidative stress-induced ECs. The levels of NEAT1 and miR-181d-5p were measured in serum samples from ApoE−/− mice and t-BHP-treated human umbilical vein endothelial cells (HUVECs) by qRT-PCR. The potential role of NEAT1 in viability, migration and apoptosis was analyzed by CCK-8, cell metastasis, flow cytometry, dual-luciferase reporter, RNA immunoprecipitation and Western blot assays using HUVECs overexpressing NEAT1. The expression of NEAT1 was increased, but miR-181d-5p expression was decreased in serum samples from both ApoE−/− mice and t-BHP-treated HUVECs. Overexpression of NEAT1 increased viability, migration and CDKN3 expression but decreased apoptotic rates, caspase-3 activity and miR-181d-5p expression in HUVECs. In addition, NEAT1 acted as a promoter of the proangiogenic capacity of HUVECs by targeting miR-181d-5p/CDKN3. Altogether, these findings indicate that NEAT1 may exert a protective effect on HUVECs by regulating the miR-181d-5p/CDKN3A axis.