RÉSUMÉ
Background: Coronary atherosclerotic heart disease (CAD) is an inflammatory vascular disease caused by atherosclerosis. Long non-coding RNAs are involved in the pathophysiological process of coronary heart disease. Here we investigated the regulatory effects of lncRNA PVT1 (PVT1) in human coronary artery endothelial cells (HCAECs).Methods: qRT-PCR and western blot were performed to detect gene and protein expressions. CCK-8, flow cytometry and wound healing assays were used to determine cell viability, apoptosis and migration of HCAECs. The binding relationship among miR-532-3p, PVT1 and MAPK1 was verified by dual luciferase reporter assay.Results: Overexpression of PVT1 markedly reduced cell apoptosis and increased cell proliferation and migration. However, miR-532-3p upregulation suppressed cell proliferation and migration and promoted apoptosis of HCAECs. PVT1 suppressed the expression of miR-532-3p via directly targeting miR-532-3p. And miR-532-3p overexpression abolished the effect of PVT1 upregulation on proliferation and apoptosis in HCAECs. Furthermore, MAPK1 acted as a target gene of miR-532-3p and miR-532-3p inhibited MAPK1 expression.Conclusion: PVT1 promoted MAPK1 expression by targeting miR-532-3p, thus inhibiting HCAECs apoptosis and promoting cell proliferation, suggesting PVT1 might have great potential as a therapeutic target for CAD.
RÉSUMÉ
BACKGROUND: Coronary artery disease (CAD) is a common heart disease with high incidence and mortality. Myocardial ischemia is the main type of CAD, which negatively affects health worldwide. The aim of the present study was to investigate the function and mechanism of myocardial infarction-associated transcript (MIAT) in myocardial ischemia. METHODS: Human cardiomyocytes (HCM) were treated with oxygen-glucose deprivation (OGD) to set the in vitro model and mouse myocardial ischemia/reperfusion (I/R) was set for in vivo model. Cell viability and apoptosis were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, flow cytometry, and immunofluorescence analysis. Inflammatory cytokines levels were detected by enzyme-linked immunosorbent assay. Gene and protein expressions were identified by quantitative real time-polymerase chain reaction or Western blotting. The interaction of MIAT, miR-181a-5p, and janus kinase 2 (JAK2) was identified by dual-luciferase report assay. Mouse heart tissues histopathological condition were observed by hematoxylin and eosin assays. RESULTS: Expression of MIAT and JAK2 were increased in OGD-treated HCM and mice of I/R model group, and miR-181a-5p was decreased. MIAT silencing could reverse the OGD treatment induced cell proliferation inhibition, cleaved caspase-3 and Bcl2-associated X (Bax) levels increased, while those of B-cell lymphoma-2 (Bcl-2) and mitochondria's cyt-C decreased. Besides, MIAT knockdown attenuated the OGD-induced increase of tumor necrosis factor-α, interleukin (IL)-1ß, and IL-6 levels. Moreover, MIAT targeted miR-181a-5p to enhance the expression of JAK2 and signal Transducer and Activator of Transcription 3 (STAT3), and miR-181a-5p overexpression promoted proliferation, whereas it inhibited apoptosis in OGD-induced cardiomyocytes. Furthermore, the regulatory effects of MIAT knockdown in cell proliferation, apoptosis, and inflammatory injury was reversed by inhibition of miR-181a-5p or overexpression of JAK2 in OGD-treated HCM. Knockdown of MIAT reduced myocardial injury caused by I/R treatment in vivo. CONCLUSION: MIAT knockdown inhibited apoptosis and inflammation by regulating JAK2/STAT3 signaling pathway via targeting miR-181a-5p in myocardial ischemia model. MIAT can be a possible therapeutic target for controlling the progression of myocardial ischemia.