Role Of Long Noncoding RNA TUG1 In Viral Myocarditis And The Underlying Mechanism

BackgroundThe pathogenesis of viral myocarditis induced by coxsackievirus B3(CVB3)infection is complex,and many lnc RNAs are involved,but the role and mechanism of taurine upregulated gene 1(lncTUG1)in VMC have not been elucidated.ObjectiveTo study the role of taurine up-regulated gene 1(lncTUG1)in viral myocarditis caused by CVB3 infection,and preliminarily clarify its role in cardiomyocyte pyroptosis induced by virus infection and its molecular mechanism.MethodsVMC animal models was constructed by intraperitoneal injection of CVB3 into 3-4 week old male Balb/c mice,and the body weight,mental status and survival rate were observed and recorded;the cardiac function was detected by echocardiography,and the inflammatory infiltration of heart tissue was observed by HE staining.Expression of CVB3 coat protein VP1 and lncTUG1 in mouse heart tissues by RT-q PCR;western blot was used to detect the expression of pyroptosis-related proteins IL-1β,ASC,Cleaved Caspase-1,Caspase-1,GSDMD,GSDMD-N,NLRP3.Expression of intracellular VP1 and lncTUG1 detected by RT-q PCR in HL-1 cells cultured in vitro and infected with CVB3;western blot was used to detect the expression of pyroptosis-related proteins.The expression of lncTUG1 was knocked down by si RNA in VMC animals and cell models,and the changes in the level of pyroptosis-related proteins were detected by western blot.Bioinformatic methods were used to find the mi RNA target(mi R-378a-3p)downstream of lncTUG1,and the downstream target molecule m RNA(Grb2)of mi R-378a-3p was screened.The effects of these targets on myocardial pyroptosis induced by CVB3 infection were analyzed by gene knockout and overexpression techniques combined with cofunctional tests.Results1.LncTUG1 expression levels were significantly increased in both cellular and animal models of VMC.2.Significant upregulation of cardiomyocyte pyroptosis-related protein levels was detected in both in vivo and in vitro VMC models.3.Knockdown of lncTUG1 expression in HL-1 cells infected with CVB3 reversed CVB3-induced cell pyroptosis.Knockdown of lncTUG1 expression in a VMC mouse model slowed body weight loss,reduced inflammatory lesions and inflammatory infiltrates in myocardial tissue,and down-regulated levels of pyroptosis-related proteins.4.The database predicted mi R-378a-3p as a downstream target of lncTUG1,and mi R-378a-3p expression was down-regulated in the VMC model.5.When mi R-378a-3p was overexpressed,the expression levels of pyroptosis-related proteins in cardiomyocytes were all decreased.When mi R-378a-3p inhibitor and si TUG1 inhibitor were cotransfected into HL-1 cells,mi R-378a-3p inhibitor could reverse the inhibitory effect of si TUG1 on CVB3-induced pyroptosis.After mi R-378a-3p mimic and si TUG1 were co-transfected into HL-1 cells,the inhibitory effect of si TUG1 on CVB3-induced pyroptosis was enhanced.6.The database predicts Grb2 as a downstream target of mi R-378a-3p,and Grb2 expression is upregulated in viral myocarditis models.Conclusion1.CVB3 induces cardiomyocyte pyroptosis in in vivo and in vitro VMC models;2.lncTUG1 is involved in CVB3-induced cardiomyocyte pyroptosis and interference with lncTUG1 expression significantly ameliorates pyroptosis in VMC;3.lncTUG1 may play a role in promoting pyroptosis of cardiomyocytes in CVB3 infected VMC through lncTUG1/mi R-378a-3p/Grb2 axis.