Ding Huaisheng, Yao Jianhui, Xie Hongxiang, Wang Chengyu, Chen Jing, Wei Kaiyong, Ji Yangyang, Liu Lihong
Cardiovascular Department, Meishan People's Hospital, Meishan, China.
Front Physiol. 2021 Sep 30;12:709123. doi: 10.3389/fphys.2021.709123. eCollection 2021.
Diabetic cardiomyopathy (DCM) is a complication of diabetes mellitus, which is associated with fibrosis and microRNAs (miRs). This study estimated the mechanism of miR-195-5p in endothelial mesenchymal transition (EndMT) and myocardial fibrosis in DCM. After the establishment of DCM rat models, miR-195-5p was silenced by miR-195-5p antagomir. The cardiac function-related indexes diastolic left ventricular anterior wall (LVAW, d), systolic LVAW (d), diastolic left ventricular posterior wall (LVPW, d), systolic LVPW (d), left ventricular ejection fraction (LVEF), and fractional shortening (FS) were measured and miR-195-5p expression in myocardial tissue was detected. Myocardial fibrosis, collagen deposition, and levels of fibrosis markers were detected. Human umbilical vein endothelial cells (HUVECs) were exposed to high glucose (HG) and miR-195-5p was silenced. The levels of fibrosis proteins, endothelial markers, fibrosis markers, EndMT markers, and transforming growth factor beta 1 (TGF-β1)/Smads pathway-related proteins were measured in HUVECs. The interaction between miR-195-5p and Smad7 was verified. , miR-195-5p was highly expressed in the myocardium of DCM rats. Diastolic and systolic LVAW, diastolic and systolic LVPW were increased and LVEF and FS were decreased. Inhibition of miR-195-5p reduced cardiac dysfunction, myocardial fibrosis, collagen deposition, and EndMT, promoted CD31 and VE-cadehrin expressions, and inhibited α-SMA and vimentin expressions. , HG-induced high expression of miR-195-5p and the expression changes of endothelial markers CD31, VE-cadehrin and fibrosis markers α-SMA and vimentin were consistent with those after silencing miR-195-5p. In mechanism, miR-195-5p downregulation blocked EndMT by inhibiting TGF-β1-smads pathway. Smad7 was the direct target of miR-195-5p and silencing miR-195-5p inhibited EndMT by promoting Smad7 expression. Collectively, silencing miR-195-5p inhibits TGF-β1-smads-snail pathway by targeting Smad7, thus inhibiting EndMT and alleviating myocardial fibrosis in DCM.
糖尿病性心肌病（DCM）是糖尿病的一种并发症，与纤维化和微小RNA（miR）相关。本研究评估了miR-195-5p在DCM的内皮-间充质转化（EndMT）和心肌纤维化中的作用机制。建立DCM大鼠模型后，用miR-195-5p拮抗剂沉默miR-195-5p。测量心脏功能相关指标左心室前壁舒张期（LVAW，d）、左心室前壁收缩期（LVAW，s）、左心室后壁舒张期（LVPW，d）、左心室后壁收缩期（LVPW，s）、左心室射血分数（LVEF）和缩短分数（FS），并检测心肌组织中miR-195-5p的表达。检测心肌纤维化、胶原沉积及纤维化标志物水平。将人脐静脉内皮细胞（HUVECs）暴露于高糖（HG）环境中并沉默miR-195-5p。检测HUVECs中纤维化蛋白、内皮标志物、纤维化标志物、EndMT标志物及转化生长因子β1（TGF-β1）/Smads信号通路相关蛋白的水平。验证miR-195-5p与Smad7之间的相互作用。结果显示，miR-195-5p在DCM大鼠心肌中高表达。左心室前壁舒张期和收缩期、左心室后壁舒张期和收缩期均升高，而LVEF和FS降低。抑制miR-195-5p可减轻心脏功能障碍、心肌纤维化、胶原沉积和EndMT，促进CD31和血管内皮钙黏蛋白的表达，并抑制α-平滑肌肌动蛋白（α-SMA）和波形蛋白的表达。此外，HG诱导的miR-195-5p高表达以及内皮标志物CD31、血管内皮钙黏蛋白和纤维化标志物α-SMA及波形蛋白的表达变化与沉默miR-195-5p后的情况一致。机制上，下调miR-195-5p通过抑制TGF-β1-Smads信号通路阻断EndMT。Smad7是miR-195-5p的直接靶点，沉默miR-195-5p通过促进Smad7表达抑制EndMT。综上所述，沉默miR-195-5p通过靶向Smad7抑制TGF-β1-Smads-Snail信号通路，从而抑制EndMT并减轻DCM中的心肌纤维化。
