Liu Yunqi, Yin Ziwei, Xu Xueqin, Liu Chen, Duan Xiaoying, Song Qinlan, Tuo Ying, Wang Cuiping, Yang Jing, Yin Shengli
Department of Cardiac Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
NCH Key Laboratory of Assisted Circulation, Sun Yat-sen University, Guangzhou, China.
ESC Heart Fail. 2021 Feb;8(1):447-460. doi: 10.1002/ehf2.13095. Epub 2020 Nov 24.
Previous reports indicated that the Slit2-Robo signalling pathway is involved in embryonic heart development and fibrosis in other solid organs, but its function in adult cardiac fibrosis has not been investigated. Here, we investigate the role of the Slit2-Robo1 signalling pathway in cardiac fibrosis.
The right atrial tissue samples were obtained from patients with valvular heart disease complicated by atrial fibrillation during heart valve surgery and from healthy heart donors. The fibrotic animal model is created by performing transverse aortic constriction (TAC) surgery. The Robo1, Slit2, TGF-β1, and collagen I expression levels in human and animal samples were evaluated by immunohistochemistry and western blot analysis. Echocardiography measured the changes in heart size and cardiac functions of animals. Angiotensin II (Ang II), Slit2-siRNA, TGF-β1-siRNA, recombinant Slit2, and recombinant TGF-β1 were transfected to cardiac fibroblasts (CFs) respectively to observe their effects on collagen I expression level. The right atrial appendage of patients with valvular heart disease complicated by atrial fibrillation found significantly up-regulated Slit2, Robo1, TGF-β1, and collagen I expression levels. TAC surgery leads to heart enlargement, cardiac fibrosis, and up-regulation of Slit2, Robo1, TGF-β1, and collagen I expression levels in animal model. Robo1 antagonist R5 and TGF-β1 antagonist SB431542 suppressed cardiac fibrosis in TAC mice. Treatment with 100 nM Ang II in CFs caused significantly increased Slit2, Robo1, Smad2/3, TGF-β1, collagen I, PI3K, and Akt expression levels. Transfecting Slit2-siRNA and TGF-β1-siRNA, respectively, into rat CFs significantly down-regulated Smad2/3 and collagen I expression, inhibiting the effects of Ang II. Recombinant Slit2 activated the TGF-β1/Smad signalling pathway in CFs and up-regulated Periostin, Robo1, and collagen I expression.
The Slit2-Robo1 signalling pathway interfered with the TGF-β1/Smad pathway and promoted cardiac fibrosis. Blockade of Slit2-Robo1 might be a new treatment for cardiac fibrosis.
既往报道表明，Slit2-Robo信号通路参与胚胎心脏发育及其他实体器官的纤维化过程，但尚未对其在成人心脏纤维化中的作用进行研究。在此，我们研究Slit2-Robo1信号通路在心脏纤维化中的作用。
右心耳组织样本取自心脏瓣膜手术中合并房颤的瓣膜性心脏病患者以及健康心脏供体。通过进行横向主动脉缩窄（TAC）手术建立纤维化动物模型。采用免疫组织化学和蛋白质印迹分析评估人和动物样本中Robo1、Slit2、TGF-β1和I型胶原的表达水平。超声心动图测量动物心脏大小和心功能的变化。分别将血管紧张素II（Ang II）、Slit2-siRNA、TGF-β1-siRNA、重组Slit2和重组TGF-β1转染至心脏成纤维细胞（CFs），观察它们对I型胶原表达水平的影响。合并房颤的瓣膜性心脏病患者的右心耳中，Slit2、Robo1、TGF-β1和I型胶原的表达水平显著上调。TAC手术导致动物模型心脏增大、心脏纤维化，以及Slit2、Robo1、TGF-β1和I型胶原表达水平上调。Robo1拮抗剂R5和TGF-β1拮抗剂SB431542可抑制TAC小鼠的心脏纤维化。用100 nM Ang II处理CFs可导致Slit2、Robo1、Smad2/3、TGF-β1、I型胶原、PI3K和Akt的表达水平显著升高。分别将Slit2-siRNA和TGF-β1-siRNA转染至大鼠CFs中，可显著下调Smad2/3和I型胶原的表达，抑制Ang II的作用。重组Slit2激活CFs中的TGF-β1/Smad信号通路，并上调骨膜蛋白、Robo1和I型胶原的表达。
Slit2-Robo1信号通路干扰TGF-β1/Smad通路并促进心脏纤维化。阻断Slit2-Robo1可能是治疗心脏纤维化的一种新方法。
