The Role And Mechanism Of LncRNA MEG3 And MiRNA-361-5p In Coronary Atherosclerosis

Background The proliferation and apoptosis of vascular smooth muscle cells(VSMCs)are the important reasons for the occurrence and development of atherosclerosis.A repair reaction occurs when the local blood vessel is damaged,which is local vascular reconstruction and remodeling mediated by a variety of cytokines and growth factors,mainly including proliferation and apoptosis of vascular smooth muscle cells,secretion and accumulation of extracellular matrix and intimal hyperplasia.This is of great significance for atherosclerotic diseases.In recent years,studies have found that long non-coding RNAs(lnc RNAs)and Micro RNAs(mi RNAs)have important regulatory effects on the proliferation and apoptosis of VSMCs,so the studies on the relationship between lnc RNAs,mi RNAs and VSMCs have become a hot spot.At present,a large number of lnc RNAs and mi RNAs have been found,and the mechanisms of action varied.One of the research focuses is the competing endogenous RNAs(ce RNA)hypothesis.This finding is used to explain the role of RNA language in regulating RNA crosstalk and controlling biological functions.It has been determined that mi RNAs can lead to m RNAs gene silencing by binding to target m RNAs.Lnc RNAs,as a ce RNA,can interact with mi RNAs and jointly participate in the expression regulation of target m RNAs.Lnc RNAs(ce RNAs)can bind to mi RNAs by response elements,thus regulating gene silencing caused by mi RNAs.Recent studies suggest that lncRNA MEG3 may be related to the proliferation and apoptosis of VSMCs,and its possible mechanism is the focus of this study in the process of VSMCs proliferation and apoptosis.Therefore,MEG3 was selected through bioinformatics analysis,which may regulate the expression of ABCA1 through the sponge of mi R-361-5p and jointly participate in the proliferation and apoptosis of VSMCs.Objectives To investigate the relationship between MEG3,mi R-361-5p and proliferation and apoptosis of VSMCs and their interaction mechanism through the establishment of cell model.To observe the expression level of MEG3 and mir-361-5p in peripheral blood of ACS patients,as well as the relationship between different coronary artery lesion morphology,coronary intervention therapy and changes in RNAs expression.Methods and results:Methods The culture of VSMCs in vitro was used induced by oxidized low density lipoprotein(ox-LDL),the expression of MEG3,mi R-361-5p and ABCA1 was detected by real-time PCR,and ABCA1 expression was detected by Western Blot.Proliferation and apoptosis of VSMCs were measured by CCK-8 proliferative assay and flow cytometry respectively.We used knockdown and overexpression system to identify the molecular mechanism.In addition,luciferase report assay and bioinformatics analysis were used to confirm the bio-target of different factors.The clinical data of patients with chest pain were successively collected from August 2018 to October 2018 in Department of Cardiology of our hospital.Patients were divided into non-coronary heart disease group,stable angina group,unstable angina group and myocardial infarction group according to clinical symptoms,changes of ECG,changes in myocardial injury markers and results of coronary angiography.In addition to standard cardiology intensive drug therapy,percutaneous coronary intervention was performed according to coronary angiography results and patients’ wishes.The expressions of MEG3,mir-361-5p and ABCA1 in patients before and after coronary angiography or interventional therapy were detected by RT-PCR.The expression differences of the three RNAs between different groups were compared.The relationship between the morphology of coronary artery lesions and the expression level of RNAs was also analyzed.The correlation between the complexity of coronary target lesions and the stent implantation and the change in RNAs expression was studied.Results MEG3 was down-regulated and related with mi R-361-5p expression in ox-LDL injured VSMCs.Inhibition of MEG3 promotes the proliferation and decelerates apoptosis of VSMCs.Moreover,MEG3 acts as a competing endogenous RNA(ce RNA)for mi R-361-5p and further regulate ABCA1 expression regulate proliferation and apoptosis in ox-LDL injured VSMCs.Among patients with myocardial infarction,the expression level of mi R-361-5p was up-regulated compared with other groups,and the expression level of ABCA1 in the unstable angina group was lower than other groups.There was no significant difference in the expression level of lnc RNA MEG3 between the groups.In patients with collateral circulation in coronary arteries,the expression level of lnc RNA MEG3 decreased,while the expression of mi R-361-5p increased,but it was not shown to be correlated with the severity of coronary artery lesions.After PCI,the expression level of mi R-361-5p in patients was up-regulated compared with that before surgery,while the expression level of ABCA1 was decreased,and no significant changes were observed in the lnc RNA MEG3.The expressions of the three RNAs showed no correlation with the complexity of the target lesions.The expression of mi R-361-5p was positively correlated with the length of the stent,while the expression of ABCA1 was negatively correlated with the length of the it.Conclusion:1.MEG3 can be as ceRNA of mi R-361-5p to regulate the proliferation and apoptosis of VSMCs by affecting the expression of ABCA1.2.The expression level of mi R-361-5p in patients with myocardial infarction was higher than that in other groups,and the expression level of ABCA1 in the unstable angina group was lower than that in other groups.3.MEG3 and mir-361-5p may be associated with the establishment of collateral circulation of coronary arteries.4.Mi R-361-5p and ABCA1 may be involved in the process of vascular remodeling after PCI.