肝脏固有淋巴细胞亚群（ILC3）分泌GM-CSF促进肝癌免疫耗竭的机制研究

Liver is an important “non-professional” immune organ. The numerous natural immune cells and inflammatory signaling networks in the liver lead to immune escape. ILC3 is one of the liver innate lymphoid cells which is characterized by activation without TCR participation. So far, very few study has been done on the role of ILC3 in liver cancer development and progression. Our previous works showed ILC3 numbers in liver cancer tissue are positively correlated with tumor malignancy. IL-1βstimulates ILC3 to secrete GM-CSF which activates MDSCs. The activated MDSC, in turn, activates T cell lncRNA which targets NF-κB pathway and upregulates exhausted molecule expression. All of above lead to immune escape. In this project, we will focus on ILC3 to investigate the ILC3 local immune network composition and remodeling, its influence and regulation mechanism on tumor development, and to elucidate the key molecules which are involved in ILC3 paracrine GM-SCF activated MDSC leading to T cell exhaustion. We will also analyze the relationship between immune microenvironment and tumor immune escape induced by ILC3 in clinical samples. The study will help to reveal the new mechanism of ILC3 regulation on immune exhaustion in liver cancer and provide idea for new immunotherapy targeting drug development.

肝脏是机体重要的“非专职”免疫器官，肝内大量的天然免疫细胞及其炎症信号网络调控了肿瘤免疫逃逸。ILC3是新近发现的一种固有淋巴细胞，其特点是激活并不需要TCR的参与，目前有关ILC3在肝癌发生发展中的作用缺乏研究。我们前期研究发现，肝癌组织ILC3s含量与肿瘤恶性程度呈正相关，IL-1β刺激ILC3s分泌的GM-CSF能促进MDSC活化，进而激活T细胞内lncRNA，靶向NF-κB通路及上调耗竭分子，最终导致免疫逃逸。本课题拟以肝内ILC3s为切入点，探讨炎症微环境下肝内ILC3s区域免疫反应网络的组成、塑造、以及对肿瘤进展的影响和调控机制；明确ILC3s旁分泌的GM-CSF活化MDSCs促进T细胞免疫耗竭的关键作用分子；并利用临床样本分析ILC3s及其影响的免疫微环境与肿瘤免疫逃逸的关系。本项目的实施将有助于揭示肝脏ILC3s调控肝癌免疫耗竭的新机制，为探索新型靶向治疗药物提供新思路。

肝脏是机体重要的“非专职”免疫器官，肝内大量的天然免疫细胞及其炎症信号网络调控了肿瘤免疫逃逸。ILC3是新近发现的一种固有淋巴细胞，其特点是激活并不需要TCR的参与，目前有关ILC3在肝癌发生发展中的作用缺乏研究。我们研究发现，肝癌组织ILC3s含量与肿瘤恶性程度呈正相关，IL-1β刺激ILC3s分泌的GM-CSF能促进MDSC活化，进而激活T细胞内lncRNA，靶向NF-κB通路及上调耗竭分子，最终导致免疫逃逸。本课题以肝内ILC3s为切入点，明确ILC3s旁分泌的GM-CSF活化MDSCs促进T细胞免疫耗竭的关键作用分子；并利用临床样本分析ILC3s及其影响的免疫微环境与肿瘤免疫逃逸的关系。临床标本经流式检测ILCs细胞亚型的分布情况异常，发现ILC2s和ILC3s在肝癌肿瘤组织中大量富集。因此，在该项目基础上进行了进一步拓展，用单细胞测序技术展示肝癌组织ILCs单细胞图谱，细胞亚群存在显著差异；构建了肝癌进展不同阶段ILCs细胞发育的分化轨迹，发现其命运决定基因；探究了ICOS+ILC2细胞群基因信号与肝癌患者存活率成显著负相关；揭示HSP70可能是肝癌患者免疫治疗调节的关键靶标。本项目的实施将有助于揭示肝脏ILC3s调控肝癌免疫耗竭的新机制，为探索新型靶向治疗药物提供新思路。