lncRNA-TUG1通过影响eNOS和BDNF介导小鼠心肌梗死后心功能损伤

lncRNA-TUG1 mediates cardiac dysfunction after myocardial infarction in mice by affecting eNOS and BDNF

目的:探讨长链非编码RNA-牛磺酸上调基因1(long non-coding RNA-taurine up-regulated gene 1,lncRNA-TUG1)通过影响内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)和脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)在小鼠心肌梗死(myocardial infarction,MI)后心肌损伤中的作用。方法:将40只C57BL/6小鼠随机分为假手术组、MI组、空载体组及lncRNA-TUG1沉默组(构建lncRNA-TUG1沉默腺病毒并感染小鼠心肌,1周后通过冠状动脉左前降支结扎法构建MI模型)。模型构建1周后使用小动物超声仪测定小鼠心功能变化,检测结束后进行眼眶取血并收集心脏组织。RT-qPCR检测心脏梗死区lncRNA-TUG1的表达;ELISA测定心脏损伤标志物水平;TTC染色比较梗死心肌面积差异;Western blot检测梗死区心肌组织eNOS和BDNF的变化;Western blot、ELISA和RT-qPCR检测炎症因子和线粒体生物合成相关蛋白水平,评估炎症和线粒体生物合成水平。结果:(1)MI后梗死区心脏组织中lncRNA-TUG1的表达显著增多(P<0.01),腺病毒感染能有效减少lncRNATUG1表达(P<0.01);(2)与空载体组相比,沉默lncRNA-TUG1能使小鼠心肌损伤标志物下降,心功能改善,梗死心肌面积显著减少(P<0.05);(3)下调lncRNA-TUG1能显著升高MI后eNOS和BDNF水平(P<0.05);(4)沉默lncRNATUG1能减轻MI诱导的炎症反应,促进线粒体生物合成(P<0.05)。结论:抑制lncRNA-TUG1可以通过影响eNOS和BDNF介导的炎症反应和线粒体生物合成,减轻MI后小鼠的心功能损伤。

AIM:To investigate the role of long non-coding RNA-taurine upregulated gene 1(lncRNATUG1)in myocardial injury after myocardial infarction(MI)in mice.METHODS:Forty C57BL/6 mice were randomly divided into sham group,MI group,MI+empty vector(shNC)group,and MI+lncRNA-TUG1 silencing(shTUG1)group.A lncRNA-TUG1 silencing adenovirus was constructed,and the mouse myocardium was infected.Mouse MI model was established by ligation of the left anterior descending branch of the coronary artery one week later.One week after the model was established,the changes of cardiac function in mice were measured by a small-animal ultrasound apparatus.Subsequently,orbital blood and cardiac tissue were collected.The expression of lncRNA-TUG1 in the MI area was detected by RT-qPCR.The levels of cardiac injury markers were assessed by ELISA.The MI area was compared by TTC staining.The changes of myocardial endothelial nitric oxide synthase(eNOS)and brain-derived neurotrophic factor(BDNF)levels in the MI area were detected by Western blot.Inflammatory cytokines and mitochondrial biosynthesis-related proteins were detected by Western blot,ELISA and RT-qPCR to evaluate the levels of inflammation and mitochondrial biosynthesis.RE⁃SULTS:(1)lncRNA-TUG1 expression was increased in heart tissue in the infarcted area after MI(P<0.01),and adenovirus infection effectively reduced lncRNA-TUG1 expression(P<0.01).(2)Compared with MI+shNC group,silencing of lncRNA-TUG1 decreased myocardial injury marker levels,improved cardiac function,and significantly reduced the infarcted area(P<0.05).(3)Down-regulation of lncRNA-TUG1 significantly reversed the decreases in eNOS and BDNF levels caused by MI(P<0.05).(4)Silencing of lncRNA-TUG1 attenuated inflammatory response and improved mitochondrial biosynthesis after MI(P<0.05).CONCLUSION:Inhibition of lncRNA-TUG1 attenuates cardiac function injury in mice after MI by affecting eNOS/BDNF-mediated inflammatory response and mitochondrial biosynthesis.