先心病致病基因Tbx1在心梗后再生修复中作用的机制研究

The anatomic abnormalities of congenital heart disease (CHD) patients can be remedied through surgery. However, it is still largely unknown whether the underlying genetic lesion affects the occurrence and prognosis of acquired cardiovascular disease in adulthood. TBX1 is a well known CHD gene and a key regulator of cardiac progenitor development, but it is rarely expressed in adult heart. Recently, we found that Tbx1 is activated to express in cells like lymphatic endothelial cells after infarction. Hearts with the lymphatic endothelial cell specific deletion of Tbx1 have worse cardiac function than those in control group, indicating a critical role of Tbx1 in cardiac regeneration and repair following infarction. In this project, we propose to further delineate the role of Tbx1 in cardiac repair and to clarify the roles of Tbx1 in neo-lymphangiogenesis and in regulating biological behavior of lymphatic endothelial cells following infarction, using molecular genetics and cell biology techniques etc. Furthermore, we are planning to dissect the molecular mechanisms how Tbx1 regulates downstream targets and how Tbx1 itself is activated in the lymphatic endothelial cells after infarction. In this way, we look forward to elucidating the effect of Tbx1 absence on the adult cardiovascular disease and providing knowledge for better management of adult CHD patients.

先心病患者的解剖畸形可以手术矫正，但致病的遗传损害仍然存在，该损害是否影响成年心血管疾病的发生和预后？目前所知甚少。先心致病基因TBX1是心脏祖细胞发育的关键调控因子，但其在成体心脏中基本不表达。申请人最近发现，心梗后Tbx1在包括淋巴管内皮在内的心脏细胞中激活表达，而且淋巴管内皮特异性敲除Tbx1小鼠心梗后的心功能较对照组更为恶化，提示Tbx1在心梗后的再生修复中有重要作用。本项目拟用分子遗传、细胞生物学等方法明确Tbx1在心梗后损伤修复中的作用，阐明Tbx1对心脏淋巴管增生的作用及对淋巴管内皮细胞生物学行为的影响。并通过RNA-Seq、ChIP-Seq、4C-Seq等方法相结合，系统研究转录因子Tbx1在心梗后淋巴管内皮细胞中调控下游基因表达以及自身被激活表达的分子调控机制。借此，希望了解TBX1缺失对成年心血管疾病的影响，为更好地做好成年先心患者的疾病管理打下理论基础。

先心病患者的解剖畸形可以手术矫正，但致病的遗传损害仍然存在，该损害是否影响成年心血管疾病的发生和预后? 目前所知甚少。先心致病基因TBX1是心脏祖细胞发育的关键调控因 子，但其在成体心脏中基本不表达。本项目通过构建小鼠心肌梗死模型发现Tbx1在心梗损伤后在心脏淋巴管内皮中特异性激活。应用内皮和淋巴内皮条件性敲除小鼠发现,Tbx1对心梗损伤后淋巴管再生有促进作用,Tbx1缺失会造成心脏功能恶化明显,心肌梗死面积加大。通过分子生物学手段揭示了Tbx1在淋巴管内皮中的转录调控机制及其调控靶点基因。进一步应用心脏组织学分析和单细胞转录组技术发现Tbx1基因缺陷小鼠心肌梗死后心脏免疫反应出现异常,提示心脏淋巴内皮具有重要的免疫调控功能。这些结果揭示了TBX1缺失对成年心血管疾病的影响，为发现心脏损伤后新的治疗靶点以及更好地做好成年先心患者的疾病管理打下理论基础。