ABSTRACT
Introduction: In this study, we investigated the role of the long non-coding RNA GAPLINC in atherosclerosis under oxidized low-density lipoprotein (ox-LDL) treatment. Material and methods: We utilized ox-LDL exposed human aortic endothelial cells as an in-vitro model. The expression level of GAPLINC was quantified by qPCR in different times and concentrations of ox-LDL treatment conditions. Cell apoptosis rate and cell cycle profiles were assessed by flow cytometry and TUNEL assay. The target association was confirmed using a luciferase reporter assay and Western blot. Results: We found that GAPLINC expression was induced by ox-LDL treatment, but cell proliferation ability was significantly inhibited. We further confirmed that overexpressing of lncRNA GAPLINC in ox-LDL-exposed HAECs decreased cell proliferation by increasing cell apoptosis and arresting cell cycle in G2/M and S phase. Importantly, the detailed mechanistic analysis elucidated that LncRNA GAPLINC acts as a decoy to sequester miR-183-5p to prevent it from binding to target PDCD4. MiR-183-5p targets GAPLINC, and PDCD4 is a downstream target of miR-183-5p, and the cellular effects of this direct interaction were confirmed by a rescue assay experiment. Conclusions: The present study demonstrates that upregulation of lncRNA GAPLINC represses the binding of miR-183-5p to the PDCD4 promoter region and then promotes PDCD4 expression, thereby inducing cell apoptosis and suppressing endothelial cell proliferation.
ABSTRACT
Vascular endothelial dysfunction is associated with the progress of many diseases. Circular RNAs (circRNAs) take part in the dysfunction of vascular endothelium. CircRNA hsa_circ_0008360 (circ_0008360) is dysregulated in high glucose-treated vascular endothelium, while the role and mechanism of circ_0008360 in high glucose-induced dysfunction remain unknown. Human umbilical vascular endothelium cells (HUVEC) were stimulated via high glucose. The abundances of circ_0008360, miR-186-5p and cyclin D2 (CCND2) were examined via quantitative real-time polymerase chain reaction or western blot. Vascular endothelial dysfunction was assessed via cell viability, apoptosis, migration and tube formation. The target relationship between miR-186-5p and circ_0008360 or CCND2 was analyzed via dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation analyses. Circ_0008360 expression was enhanced in high-glucose-treated HUVEC. Circ_0008360 silence mitigated high glucose-induced suppression of viability, migration, tube formation, and increase in apoptosis in HUVEC. MiR-186-5p was sponged by circ_0008360, and miR-186-5p inhibition reversed the effect of circ_0008360 silence on high glucose-induced vascular endothelial dysfunction. MiR-186-5p alleviated high glucose-induced vascular endothelial dysfunction via targeting CCND2. CCND2 interference abolished the aggravated effect of circ_0008360 on high glucose-induced vascular endothelial dysfunction. Circ_0008360 knockdown attenuated high glucose-induced vascular endothelial dysfunction via regulating miR-186-5p and CCND2, indicating circ_0008360 might act as a target for the treatment of vascular endothelial dysfunction.Abbreviations: circRNAs, circular RNAs; HUVEC, human umbilical vascular endothelium cells; CCND2, cyclin D2; XPNPEP3, X-prolyl aminopeptidase 3; ceRNAs, competing endogenous RNAs; miRNAs, microRNAs; qRT-PCR, quantitative real-time polymerase chain reaction; RIP, RNA immunoprecipitation; HIF-1α, hypoxia inducible factor 1 alpha; TLR3, toll-like receptor 3; AKAP12, A-Kinase Anchoring Protein 12; ox-LDL, oxidized low-density lipoprotein; HG, high glucose; NG, normal glucose.
