Fstl1调节的TGF-β1/Smads信号通路在CTEPH所致右心衰的作用及调节机制研究

Right heart failure is a main causes of death for chronic thromboembolic pulmonary hypertension (CTEPH). Ventricular remodeling is the pathological feature of chronic heart failure. Follicle like protein 1 (Fstl) is a marker of left ventricular remodeling. The role of Fstl in right ventricular remodeling and its mechanism remain unclear. With cardiac magnetic resonance imaging (CMR), we found the right ventricular fibrosis in patients with CTEPH, meanwhile serum Fstl level elevated. Therefore, we propose that Fstl participates in the TGF-β1 /Smads.signaling pathway and promotes the activation of fibroblasts and the expression of extracellular matrix which will lead to right ventricular remodeling. From the cellular level we investigate TGF-β1 /Smads pathway in the proliferation and activation of fibroblasts through Fstl overexpression and interference. The expression of TGF- 1 and Smads in right ventricular myocardium of CTEPH in Fstl.knockout mice and wild-type mice were compared. To analyze the relationship between the expression of Fstl and the right ventricular remodeling in porcine CTPEH model. Right ventricular remodeling determined with CMR and serum Fstl1 were correlated in patients with CTEPH. We will provide a evidence for new therapeutic targets of CTEPH.

右心衰是造成慢性血栓栓塞性肺动脉高压（CTEPH）患者不良预后的关键因素，但右心衰分子机制尚不明确。研究显示卵泡抑素样蛋白1（Fstl1）参与的TGF-β1/Smads信号通路与左心衰密切相关。课题组采用心脏磁共振成像（CMR）显示CTEPH患者右心衰伴心肌纤维化且血清Fstl1升高。因此提出假设：CTEPH发展过程中Fstl1参与TGF-β1/Smads信号通路，影响心肌成纤维细胞活化及细胞外基质表达，参与右室重构。基于已有理论和前期研究，本研究拟从(1)细胞水平通过干预Fstl1表达，观察右室成纤维细胞TGF-β1/Smads变化及细胞增殖活化；(2)构建小鼠及猪CTEPH模型分析Fstl1调控TGF-β1/Smads信号通路致右室的变化；(3) CMR测定CTEPH右心衰与Fstl1表达水平的关系；为CTEPH右心衰的评估及治疗提供新靶点。

背景： FSTL1在慢性血栓栓塞性肺动脉高压（CTEPH）右室重构中的作用及调节尚不明确。研究内容：细胞水平研究Fstl1变化对心肌成纤维活化细胞的增殖的影响及TGF-β1/Smads变化。小鼠及猪CTEPH模型干预Fstl1表达，观察右室成纤维细胞TGF-β1/Smads变化与右室重构的关系；CTEPH患者血清Fstl1表达与血流动力学及右室重构的关系，CTEPH患者肺动脉血栓内膜剥脱术(PEA)前后及肺动脉球囊扩张术(BPA)治疗前后Fstl1水平的变化。结果及数据：FSTL1腺病毒载体转染成心肌纤维细胞较Fstl1 siRNA 干扰心肌成纤维细胞及空白对照组细胞FSTL1表达升高，心肌成纤维细胞迁徙能力增强。空白对照组心肌成纤维细胞的TGF-β1及Smad2 表达略高于FSTL1腺病毒载体转染组低于Fstl1 siRNA组，Smad3水平三组间无显著统计学差异。重组人Fstl1刺激心肌成纤维细胞,显著增强其增殖和迁移能力且Fstl1刺激具有浓度依赖性，当浓度100 ng/mL时心肌成纤维细胞增殖和迁移能力最为显著。小鼠CTEPH模型心肌HE染色显示右室心肌明显肥厚，Masson染色成纤维细胞增生。腹腔注射组重组Fstl1组CTEPH小鼠心肌及血清表达FSTL1水平高于空白对照组(P<0.001)，CTEPH组心肌组织FSTL1及 Smads2 表达升高（p<0.001）。猪CTEPH腹腔注射组重组心肌及血清表达FSTL1水平高于空白对照组(P<0.001)，TGFβ1 表达低于对照组(p<0.001)。CTEPH患者血清Fstl1较正常对照组明显升高，CTEPH患者血清Fstl1浓度与右室/左室面积比（r=0.976）及右心室滞留血流（r=0.67）正相关，与心室前向血流（r=-0.58）及延迟射血血流负相关（r=-0.62)。心肌纤维化患者血清Fstl1水平高于不伴随心肌纤维化患者水平（U=22.17，p=0.004），BPA后Fstl1明显减低（18.5&96.6，p<0.001）。PEA患者右心室血清Fstl1水平与肺血管阻力正相关(r=0.401).科学意义：Fstl1参与心肌成纤维细胞活化及增殖，参与CTEPH右心室重构，Fstl1可能做为评估CTEPH的血清指标。