巨噬细胞TSP1在血管紧张素II诱导的心肌纤维化中的作用与机制研究

Cardiac fibrosis is a significant global health problem associated with nearly all forms of heart diseases such as heart failure. It usually appears in the end stage of cardiovascular diseases and contributes to irreversible damage to heart function. Macrophages which are recruited into the interstitial myocardium promotes the transdifferentiation of cardiac fibroblast (CF) to myofibroblast via releasing inflammatory factors and cytokines, but the underlying mechanisms aren’t fully understood. Our preliminary experiments found 1) TSP1 was highly expressed in myocardial interstitial macrophages in the cardiac fibrosis model induced by angiotensin II (Ang II); 2) Ang II upregulated TSP1 expression in macrophage in a STAT3-dependent manner; 3) Knockdown of TSP1 in macrophages blunted TGFβ1 signaling in CFs co-cultured. Therefore, we hypothesize that Ang II increases TSP1 expression in macrophage through STAT3 and release of TSP1 leads to activation of the TGFβ1 pathway in CFs, which in turn promotes the transdifferentiation of CF to myofibroblasts and accelerates cardiac fibrosis. In this study, we’ll validate the hypothesis via performing bone marrow transplantation, cell co-culture and lentivirus transfection and so on. Our results will provide a new therapeutic strategy for cardiac fibrosis and related diseases.

心肌纤维化是心力衰竭等心血管疾病的病理生理学基础，通常出现在疾病进程终末阶段，对心脏功能造成不可逆性损伤。巨噬细胞被募集到心肌间质，并通过释放炎症因子和细胞因子等方式促进心脏成纤维细胞向肌成纤维细胞转化是心肌纤维化的重要发病机制，但具体分子机制尚不清楚。预实验研究发现血管紧张素II（AngII）诱导的心肌纤维化模型中TSP1在心肌间质巨噬细胞中高表达，细胞实验证实AngII可以在巨噬细胞中以STAT3依赖的方式上调TSP1的表达，共培养实验证实敲除TSP1抑制TGFβ1信号通路激活。因此我们提出科学假说，即AngII通过STAT3上调巨噬细胞TSP1表达，导致TGFβ1通路激活，进而促进成纤维细胞的表型转化，加重心肌纤维化进程。拟通过骨髓移植、细胞共培养等技术研究巨噬细胞TSP1在AngII介导的心肌纤维化过程中作用与机制，以期为相关疾病的治疗提供新思路和潜在靶点。

心脏纤维化是心力衰竭等心血管疾病的病理生理学基础，通常出现在疾病进程终末阶段，对心脏功能造成不可逆性损伤。因此，探讨心脏纤维化的分子机制将为临床相关疾病的防治提供理论基础。本项目检测了睡眠呼吸暂停的患者及间歇性缺氧暴露的小鼠血浆TSP1水平，通过体内和体外实验验证了TSP1对心脏成纤维细胞激活和心脏纤维化的促进作用。进一步，通过细胞及分子生物学实验阐明了间歇性缺氧通过激活JAK2介导STAT3 Tyr705位点磷酸化，从而调控TSP1表达的分子机制。同时，药理性抑制STAT3和PostnPromoter-AAV9靶向敲除心脏成纤维细胞中的STAT3改善了间歇性缺氧加重的血管紧张素II诱导心脏纤维化和心功能障碍。本研究阐明了STAT3/TSP1/Smad通路在心脏成纤维细胞激活和心脏纤维化中的作用，揭示了TSP1上游新的调控方式，拓展了领域内对JAK2/STAT3信号通路的认识，为特异性改善心脏纤维化相关疾病的治疗提供新的思路和策略。该研究成果于2020年在Elife杂志上发表。本项目整体上，发表基金标注论文6篇，其中项目负责人作为第一作者或通讯作者的SCI论文4篇；相关研究成果申请国家发明专利1项。