美国圣犹大儿童研究医院Hongbo Chi小组取得一项新突破。他们利用体内单细胞CRISPR筛选绘制了癌症中T细胞命运调节的基因组图谱。这一研究成果发表在2023年11月15日出版的国际学术期刊《自然》上。

研究人员利用体内单细胞CRISPR筛选系统地绘制了因果基因调控网络，并发现CD8⁺细胞毒性T细胞（CTL）分化的检查点。首先，前体衰竭T细胞（Tpex）退出静止状态后，开始向中间终末衰竭T细胞（Tex）连续分化。这一过程分别受到IKAROS和ETS1的调控，这两个基因的缺失分别抑制和增加了mTORC1相关的代谢活动。免疫检查点阻断（ICB）后，IKAROS缺陷细胞积累为代谢静止的Tpex细胞群，其分化潜力有限。相反，靶向ETS1可促进Tpex向中间态Tex细胞分化和代谢重构，从而提高抗肿瘤免疫和ICB的疗效。

从机理上讲，TCF-1和 BATF分别是IKAROS和ETS1的靶点。其次，RBPJ-IRF1通路促进了中间态Tex细胞向末端Tex细胞的分化。总之，该研究表明Tpex细胞从静止态释放和Tex细胞增殖状态是抗肿瘤效应的关键影响因素，并为整合细胞命运调控组和癌症免疫可重塑性的决定因素提供了一个系统框架。

据了解，CTL协调抗肿瘤免疫，并表现出固有的异质性，Tpex而非Tex能够对现有免疫疗法产生反应。人们对维持CTL分化的基因调控网络以及是否能在功能上重新活化Tex细胞反应尚不完全清楚。

附：英文原文

Title: Single-cell CRISPR screens in vivo map T cell fate regulomes in cancer

Author: Zhou, Peipei, Shi, Hao, Huang, Hongling, Sun, Xiang, Yuan, Sujing, Chapman, Nicole M., Connelly, Jon P., Lim, Seon Ah, Saravia, Jordy, KC, Anil, Pruett-Miller, Shondra M., Chi, Hongbo

Issue&Volume: 2023-11-15

Abstract: CD8+ cytotoxic Tcells (CTLs) orchestrate antitumour immunity and exhibit inherent heterogeneity1,2, with precursor exhausted T (Tpex) cells but not terminally exhausted T (Tex) cells capable of responding to existing immunotherapies3,4,5,6,7. The gene regulatory network that underlies CTL differentiation and whether Tex cell responses can be functionally reinvigorated are incompletely understood. Here we systematically mapped causal gene regulatory networks using single-cell CRISPR screens in vivo and discovered checkpoints for CTL differentiation. First, the exit from quiescence of Tpex cells initiated successive differentiation into intermediate Tex cells. This process is differentially regulated by IKAROS and ETS1, the deficiencies of which dampened and increased mTORC1-associated metabolic activities, respectively. IKAROS-deficient cells accumulated as a metabolically quiescent Tpex cell population with limited differentiation potential following immune checkpoint blockade (ICB). Conversely, targeting ETS1 improved antitumour immunity and ICB efficacy by boosting differentiation of Tpex to intermediate Tex cells and metabolic rewiring. Mechanistically, TCF-1 and BATF are the targets for IKAROS and ETS1, respectively. Second, the RBPJ–IRF1 axis promoted differentiation of intermediate Tex to terminal Tex cells. Accordingly, targeting RBPJ enhanced functional and epigenetic reprogramming of Tex cells towards the proliferative state and improved therapeutic effects and ICB efficacy. Collectively, our study reveals that promoting the exit from quiescence of Tpex cells and enriching the proliferative Tex cell state act as key modalities for antitumour effects and provides a systemic framework to integrate cell fate regulomes and reprogrammable functional determinants for cancer immunity.

DOI: 10.1038/s41586-023-06733-x

Source: https://www.nature.com/articles/s41586-023-06733-x