1-磷酸鞘胺醇通过其受体3改善压力超负荷诱导的病理性心肌肥厚

Role of sphingosine-1-phosphate on amelioration of pressure overload-induced pathological myocardial hypertrophy through sphingosine-1-phosphate receptor 3

目的研究1-磷酸鞘胺醇(S1P)与其受体3(S1PR3)在压力超负荷诱导的病理性心肌肥厚的作用及其机制。方法将10~12周龄的雄性C57BL/6野生型小鼠和S1PR3基因敲除纯合子(S1PR3-/-)小鼠分为4组:假手术(sham)组、sham+S1P裂解酶抑制剂(THI)组、胸主动脉缩窄术(TAC)组和TAC+THI组。各组小鼠检测血浆和心脏组织中S1P的水平;测量心脏重量和胫骨长度;心脏超声检测心功能;苏木素-伊红(HE)染色与麦胚凝集素(WGA)染色观察心肌细胞横截面积大小;二氢乙啶(DHE)染色检测心脏组织活性氧(ROS)水平;蛋白质印迹法(Western blot)和反转录聚合酶链反应(qPCR)检测心脏组织中心肌肥厚标志物和磷酸化STAT3的表达变化情况。AC16人心肌细胞处理分为4组:对照组、AngⅡ/H_(2)O_(2)组、AngⅡ/H_(2)O_(2)+S1P组和AngⅡ/H_(2)O_(2)+S1P+S3I-201(STAT3抑制剂)组。鬼笔环肽(Phalloidin)染色观察各组心肌细胞横截面积大小;Western blot检测各组心肌肥厚标志物的表达变化;DHE染色检测各组ROS水平。结果动物实验结果显示,THI显著提高小鼠血浆和心脏中S1P水平,差异有统计学意义(均为P<0.001)。与野生型小鼠相比,THI并不能改善S1PR3-/-小鼠的心功能和病理性心肌肥厚,以及减少心脏组织中的ROS生成。此外,在S1PR3-/-小鼠中,THI不能逆转压力超负荷诱导的心脏组织中的磷酸化STAT3水平的降低。细胞实验结果表明,S1P能显著抑制AngⅡ诱导的心肌细胞肥大和心肌肥厚标志物的表达,且能显著减少H_(2)O_(2)诱导的ROS生成,差异有统计学意义(均为P<0.001)。但均可被S3I-201逆转,差异有统计学意义。结论S1P通过S1PR3改善压力超负荷诱导的病理性心肌肥厚并减少心脏组织中ROS的生成,可能是通过激活JAK/STAT3信号通路发挥该效应。

Objective To study the role and mechanism of sphingosine-1-phosphate(S1P)and its receptor 3(S1PR3)on amelioration of pressure overload-induced pathological myocardial hypertrophy.Methods Male C57BL/6 wild-type mice and S1PR3 knockout homozygous mice(S1PR3-/-)(10-12 weeks old)were divided into 4 groups:sham,sham+2-acetyl-4(5)-tetrahydroxybutyl imidazole(THI),thoracic artery coarctation(TAC),TAC+THI.The levels of S1P in the plasma and heart were tested;the weight of heart and the length of tibia were measured;cardiac function of mice was detected by echocardiography;the cross-sectional area of cardiomyocytes was observed by hematoxylin-eosin(HE)and wheat germ agglutinin(WGA)staining;the levels of reactive oxygen species(ROS)in the heart were detected by dihydroethidium(DHE)staining;western blot and qPCR were used to detect the changes of myocardial hypertrophy markers and the phosphorylation changes of STAT3 in each group.AC16 human cardiomyocytes were divided into 4 groups:control group,AngⅡ/H_(2)O_(2) group,AngⅡ/H_(2)O_(2)+S1P group,AngⅡ/H_(2)O_(2)+S1P+S3I-201(STAT3 inhibitor)group.Phalloidin staining was used to observe the cross-sectional area of cardiomyocytes;western blot was used to detect the changes of myocardial hypertrophy markers;DHE staining was used to detect the levels of ROS.Results The results of animal experiments showed that THI significantly elevated the levels of S1P in the plasma and heart of mice,the difference was statistically significant(all P<0.001).Compared with wild-type mice,THI did not improve cardiac function induced by pressure overload,amelioration of pathological myocardial hypertrophy and reduction of ROS production of heart in S1PR3-/-mice.Furthermore,in S1PR3-/-mice,THI did not increase the level of p-STAT3 in the heart induced by pressure overload.Cell experiment results showed that S1P significantly ameliorated AngⅡ-induced cardiomyocytes hypertrophy,reduced the expression of myocardial hypertrophy markers and production of ROS induced by H_(2)O_(2) with significant difference(all P<0.001).However,all of these were reversed by S3I-201,the difference was statistically significant.Conclusions S1P may ameliorate pressure overload-induced pathological myocardial hypertrophy and reduce the ROS production of heart through S1PR3,which may activate the JAK/STAT3 signalling pathway to exert this effect.