TGF-β通路对心脏弓动脉发育稳态的调控作用及机制

Abnormal development of the cardiac arch artery (known as pharyngeal arch artery, PAA) can lead to congenital heart defects. Normal development and remodeling of PAA at least include two important steps: angiogenic precursor cell formation, and the assembly of great vasculature by precursor cells and the extension to connect the dorsal aorta. Although we have found that Stat4 downstream of Nkx2.5 regulates the proliferation of great vascular endothelial progenitor cells, and its deletion leads to PAA 3-6 branch stenosis, the development of PAA is regulated by various signals from different germ layers. TGF-beta signaling is an important mechanism for regulating angiogenesis and remodeling of PAA. Its role may involve many developmental links and precursor cell types of PAA, but the specific mechanism remains unclear. In this study, we intend to use single cell sequencing technique to reveal the profile of arch artery cell lineage, dynamically track the regulatory role of TGF-beta signal in PAA development and remodeling, and establish transgenic models to identify the biological functions and regulatory mechanisms of TGF-beta signaling in various PAA precursor cells. Thus, we could reveal how TGF-beta signaling regulates the fate of precursor cells in PAA, and how to coordinate these cells to form the arch arteries. This work will improve our understanding of the regulation of PAA developmental homeostasis and provide theoretical support for the etiology and early prevention of congenital heart defects.

心脏弓动脉（PAA）发育异常可致先天性心脏缺损，PAA发育和重构包括两个重要步骤：成血管前体细胞形成、前体细胞生成血管并延伸连接背侧主动脉。我们已发现Nkx2.5下游Stat4分子调控PAA内皮前体细胞增殖，其缺失导致PAA3-6分支狭窄。但PAA发育其实受到了多个胚层众多信号的调控。其中, TGF-β信号是调控PAA血管发生、重构的重要机制，其作用可能涉及PAA发育多个环节和多个前体细胞类型，但具体机制仍未阐明。本研究拟采用单细胞测序技术揭示PAA发育各细胞类群谱系概貌，动态追踪TGF-β信号对PAA发育的调控作用；拟运用已建立转基因模型，甄别各类前体细胞中，TGF-β信号行使的生物学功能和调控机制，从而揭示TGF-β信号如何调控PAA各前体细胞的命运，以及如何调控它们协同发育形成弓动脉。该工作将丰富我们对弓动脉发育稳态调控的认识，也可为先天心脏缺损的发病机制和早期预防提供理论支持。

通过实施本项目，发现生命早期低剂量环境化学物暴露会导致子代心血管发育稳态扰动，并发现影响心血管疾病风险的若干环境危险因子，如金属混合物，醛类物质，双酚系化学物以及咖啡代谢物等。通过描绘胚胎心脏的单细胞转录组图谱，揭示了在心脏发育过程中生命早期的铅暴露引起的细胞关键事件。包括肌小节发育异常、线粒体结构功能异常、内皮细胞功能障碍和心肌纤维化，从而影响心脏发育和功能。铅会导致子代小鼠出现心脏收缩功能障碍。尽管在出生后第4周已经停止了铅暴露，生命早期的因铅暴露出现的心脏病理变化对成年期子代的心脏仍具有长期的危害作用，使它们对血管紧张素II诱导的心脏压力更加敏感，出现心脏的收缩功能减弱、心肌肥厚、纤维化、凋亡、血管损伤等心脏损伤。此外，发现尿液金属镉暴露与心血管疾病的发生风险相关，尿镉的增加与高密度脂蛋白胆固醇降低有关，高密度脂蛋白胆固醇能够介导4.91%的尿镉与心血管疾病患病率之间的关联。发现血清金属混合暴露与主动脉夹层的发生风险相关，其中金属铜的贡献程度最大，血清铜水平与高密度脂蛋白胆固醇水平呈显著负相关；还证实双酚系化合物BPAF可通过激活氧化应激导致心脏发育异常。并使用斑马鱼胚胎和人类血管内皮细胞评估了BPA 、BPF、BPS 和BPAF的发育血管毒性，主要表现为阻碍节段间血管（ISV）生长、延迟总主静脉（CCV）重塑和减少肠下血管（SIV）。.本研究将丰富我们对心脏发育稳态调控的认识，并证明了生命早期的低剂量危险因子暴露会损害胚胎期的心脏血管发育，加剧成年后第二次外界环境刺激引起的心脏病理反应，并评价了若干环境危险因子与心血管疾病发病风险的关联。 .