代谢调控三型固有淋巴样细胞免疫应答效应的分子机制

Type 3 innate lymphoid cells (ILC3s) are mainly enriched in the gut, and are a group of important immune cells required for maintaining the balance of gut. However, there are still quite a few questions need to be solved about their regulatory mechanisms. My previous work systematically revealed the molecular mechanisms of transcription factor GATA-3 regulated ILC3 development, maturation, and activation. These studies have been published on the top journals in immunology, Immunity and Nature immunology, and have been cited 97 times till now. Besides transcriptional regulations, the metabolic environment in the gut also has crucial impacts on functions of the immune cells there, however, little is known about the features of ILC3 metabolism as well as their effects on the immune responses of ILC3s. Based on the established experimental resources and relative techniques we have in our lab, I hope to start the studies about it. (1) summary the features of ILC3 metabolism by combined metabolomic and proteomic analyses; (2) analyze the changes in the metabolism of ILC3 cells after their in vitro or in vivo activation; (3) demonstrate impacts of metabolisms on immune responses of ILC3s; (4) figure out the connections between small molecule metabolite or gut flora and the metabolism and function of ILC3s; (5) investigate the effect of metabolisms on epigenetic modification and gene expression in ILC3 cells.

三型固有淋巴样细胞（ILC3）主要富集于肠道，是维持肠道平衡所需的重要免疫细胞。关于其内部调控机制仍存在很多问题亟待阐明。本人之前的工作系统地揭示了转录因子GATA-3调控ILC3细胞发育、成熟及活化的分子机制，发表在免疫学顶级期刊Immunity、Nat. Immunol.上，目前引用达97次。除转录调控外，肠道中代谢环境对肠道免疫细胞的功能也有很大影响。然而关于ILC3的代谢特点及其对ILC3免疫应答效应影响的研究目前还存在很大空白。本人希望基于之前构建的实验资源和掌握的相关技术对此展开探讨。（1）结合代谢组学和蛋白质组学总结ILC3的代谢特点；（2）分析体外、体内活化过程中ILC3代谢方式的改变；（3）阐明代谢方式对ILC3免疫应答效应的影响；（4）探明小分子代谢物、肠道菌群等与ILC3代谢和功能的联系；（5）探讨ILC3代谢方式对其染色质表观遗传修饰和基因表达的影响。

1、项目背景：.三型固有淋巴样细胞（ILC3）是富集于肠道的一群天然免疫细胞，其主要产生细胞因子IL-22，对肠道稳态具有重要调节作用。关于ILC3功能的调节机制，目前仍存在很多问题需要解决。特别是肠道做为重要代谢器官，组织环境中存在大量代谢分子。代谢对免疫系统功能通常具有重要调节作用，但是其对ILC3的影响还未见报道。因此，本项目拟深入探讨ILC3的重要代谢途径及其对ILC3活化和功能的影响。..2、主要研究结果：.（1）利用代谢组学和单细胞转录组学发掘ILC3两个亚群LTi和T-bet+ ILC3的代谢特征；.（2）利用RNA-Seq、scRNA-Seq等分析ILC3在活化过程中的代谢变化；.（3）阐明了2条重要代谢通路，脂肪酸代谢、脯氨酸代谢，对ILC3活化的影响；.（4）探明脯氨酸、长链脂肪酸2种代谢物对ILC3功能、肠道稳态的影响；.（5）阐明了脯氨酸-α-酮戊二酸途径通过影响组蛋白去甲基化促进Il22转录的表观遗传调节机制。..3、重要结果：.（1）利用代谢组学、RNA-Seq、scRNA-Seq等技术，首次描绘了ILC3两个亚群的代谢特征，尤其探明ILC3活化前后主要的代谢变化。.（2）找到并阐明了脂肪酸代谢、脯氨酸代谢对ILC3活化及功能的调节作用及机制。.（3）探讨了通过干预代谢途径，促进ILC3活化，调节肠道免疫稳态的可行性。..4、关键数据及其科学意义：.（1）通过代谢组学、RNA-Seq、scRNA-Seq等分析，发现ILC3活化前后脂肪酸合成途径显著增强，为ILC3干预提供了重要依据；.（2）确定了两条干预ILC3活化和功能的有效途径，脂肪酸氧化抑制ILC3活化、脯氨酸-α-酮戊二酸途径促进ILC3活化，为炎症性肠病等的治疗提供了新的方案；.（3）阐明了脯氨酸代谢通过产生α-酮戊二酸进而影响组蛋白H3K27me3表观遗传修饰的机制，首次在ILC3中发现表观遗传对其活化具有重要影响。