Ubiquitin ligase regulation of tissue-resident T cell and anti-tumor activity

项目摘要 在恶性肿瘤中，CD8+ T细胞可以识别和消除肿瘤细胞，但由于肿瘤细胞的增殖， 由于免疫抑制性肿瘤中的慢性活化导致其抗肿瘤功能的进行性丧失 微环境在健康组织中对感染的反应中，T细胞分化成组织驻留记忆 细胞（TRM），并在清除抗原后，可以留在组织中，以调查和提供保护， 再感染当在癌症患者肿瘤中发现TRM样T细胞时， 并且观察到更好的患者结果。然而，TRM样TIL是否代表衰竭的“祖细胞”， TIL，或者是耗竭谱之外的一种单独的细胞状态，目前还不清楚。 为了更好地理解TRM样TIL、衰竭状态和TRM记忆细胞之间的关系，我们 直接比较来自急性病毒感染的TRM和来自肿瘤的耗尽的TIL，以发现转录差异 这些不同的T细胞状态之间的联系。关注TRM高表达的基因，这些基因可能介导 增强组织功能，我们问，当T细胞成为终末细胞时， 筋疲力尽，同时丧失功能。这种方法鉴定了许多与蛋白质相关的基因 调节，包括多种特征不足的E3泛素连接酶。泛蛋白的蛋白质调节 蛋白酶体系统是维持体内平衡的重要生物学过程，对细胞分化和功能至关重要， 并且先前已经显示对于记忆T细胞身份是重要的。与我们的初步数据相关联， 我们发现耗尽的TIL在其胞质溶胶中有过量的未折叠蛋白，当我们强制 通过在肿瘤特异性T细胞中表达鉴定的E3泛素连接酶，它允许更好的肿瘤控制， 提高小鼠存活率。因此，我们建议探讨蛋白质稳态与 TRM、耗竭和TRM样TIL细胞命运。目的1旨在了解鉴定的E3泛素连接酶是否 通过使用小鼠癌症模型来加强表达或敲除这些基因， 连接酶和研究耗竭T细胞的命运，或在急性病毒感染中加强表达或敲除连接酶 研究TRM细胞的命运目的2试图确定这些E3泛素连接酶的蛋白质相互作用靶点， 体外BioID邻近标记试验和质谱法，然后验证体内TIL中的靶点，并确定是否 这些连接酶在TIL中的表达可降低未折叠蛋白质丰度。理解关系 T细胞耗竭和TRM之间的联系可以为这两种分化的T细胞的生物学提供重要的新见解。 细胞群和信息的努力，以操纵T细胞的命运向TRM样TIL，以造福癌症 免疫疗法

PROJECT SUMMARY In malignancies, CD8+ T cells can recognize and eliminate tumor cells, but often fail to cure disease due to their progressive loss of antitumor function resulting from chronic activation in the immunosuppressive tumor microenvironment. In response to infection in healthy tissues, T cells differentiate into tissue-resident memory cells (TRM), and after clearance of antigen can remain lodged in tissues to survey and provide protection from reinfection. When TRM-like T cells are found in cancer patient tumors, improved responses to immunotherapy and better patient outcomes are observed. However, whether TRM-like TIL represent ‘progenitors’ of exhausted TIL, or are a separate cell state outside the exhaustion spectrum is still unclear. To better understand the relationship among TRM-like TIL, exhaustion states, and TRM memory cells, we directly compared TRM from acute viral infection and exhausted TIL from tumors to find transcriptional differences between these distinct T cell states. Focusing on genes highly expressed by TRM that may mediate their enhanced functions in tissues, we asked which of those were downregulated as T cells became terminally exhausted, coincident with loss of function. This approach identified numerous genes related to protein regulation, including multiple under-characterized E3 ubiquitin ligases. Protein regulation by the ubiquitin proteosome system is an essential biological process for homeostasis, crucial for cell differentiation and function, and has been previously shown to be important for memory T cell identity. Correlated with our preliminary data, we found that exhausted TIL have an excess of unfolded proteins in their cytosol, and when we enforced expression of the identified E3 ubiquitin ligases in tumor-specific T cells, it allowed for better tumor control and improved mouse survival. Therefore, we propose to explore the relationship between protein homeostasis and TRM, exhaustion, and TRM-like TIL cell fates. Aim 1 seeks to understand if the identified E3 ubiquitin ligases influence exhaustion or TRM cell fate by using mouse models of cancer to enforce expression or knock out these ligases and study exhaustion T cell fate, or to enforce expression or knock out the ligases in acute viral infection and study TRM cell fate. Aim 2 seeks to identify the protein-interaction targets of these E3 ubiquitin ligases by in vitro BioID proximity labeling assay and mass spectrometry, then verify the targets in vivo TIL and determine if expression of these ligases in TIL can decrease unfolded protein abundance. Understanding the relationship between T cell exhaustion and TRM can provide vital new insights into the biology of these two differentiated T cell populations and inform efforts to manipulate T cell fates towards TRM-like TIL to benefit cancer immunotherapy.