Novel mouse models for studying Tim-3 signaling

用于研究 Tim-3 信号传导的新型小鼠模型

• 批准号: 9388090
• 负责人: Lawrence P. Kane
• 金额: $ 7.71万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-18 至 2019-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9388090
• 关键词: Acute; Adverse effects; Alleles; Antibodies; Antigen Receptors; Antigens; Award; Bacteria; Biological Models; Blocking Antibodies; CD3 Antigens; CRISPR/Cas technology; Cell physiology; Cells; Chronic; Clinical Trials; Cytoplasmic Tail; Dangerousness; Data; Development; Excision; Exposure to; Functional disorder; Future; Gene Expression; Generations; Genetic; HIV; HIV Infections; Immune; Immune response; Immune system; Immunity; Immunotherapy; Impairment; Individual; Infection; Integral Membrane Protein; Knock-out; Knockout Mice; Knowledge; Length; Life; Ligands; Link; Listeria; LoxP-flanked allele; Lymphocytic choriomeningitis virus; Maintenance; Malignant Neoplasms; Malignant neoplasm of lung; Mediating; Membrane Proteins; Modeling; Mus; Mutagenesis; Nature; Outcome; Pathology; Pathway interactions; Patients; Phase; Phosphoric Monoester Hydrolases; Population; Process; Proteins; Publishing; Reagent; Recruitment Activity; Reporting; Role; Seminal; Series; Signal Transduction; Solid Neoplasm; Structure; Study models; System; T cell response; T memory cell; T-Cell Activation; T-Cell Development; T-Lymphocyte; Testing; Time; Tissues; Up-Regulation; Viral reservoir; Virus; Virus Diseases; Work; base; cell type; clinically relevant; crosslink; exhaust; exhaustion; experimental study; functional disability; melanoma; mouse model; novel; pathogen; prevent; protein biomarkers; response; targeted treatment; therapeutic target; tumor

Abstract T cell exhaustion is a state of T cell function often observed under conditions of chronic exposure to antigen, for example in some chronic viral infections and in solid tumors. However, the signals that drive and maintain exhaustion in T cells are still not well understood. Numerous surface protein markers of exhausted T cells have now been identified, including the transmembrane proteins PD-1 and Tim-3, among other markers. Antibodies that block the inhibitory effects of PD-1 are now licensed by the FDA for the treatment of melanoma and some lung cancers, with many more clinical trials still underway for other indications. Development of Tim-3 as a therapeutic target is progressing, but lags behind other targets, including PD-1, among others. Despite the extensive amount of correlative evidence linking Tim-3 expression to dysfunction of T cell activation during exhaustion, little is known about the mechanisms by which Tim-3 contributes to the development and/or maintenance of exhaustion. This has been challenging, in part due to the fact that multiple promiscuous ligands to Tim-3 have been identified. In addition, putative “blocking” antibodies to Tim-3 have not been thoroughly characterized for their effects on interactions of Tim-3 with its various ligands. Finally, we have provided evidence in multiple cell types (including T cells) that Tim-3 may actually enhance early signaling through antigen receptors, raising the question of whether some Tim-3 antibodies may actually function by actively crosslinking of Tim-3. There is therefore a need for new reagents and model systems that will allow for the more direct definition of Tim-3 function in primary T cells. Unlike PD-1 or other negative regulators of T cell activity, Tim-3 contains no motifs for recruitment of inhibitory phosphatases. Rather, our recent work suggests that Tim-3 expression actually increases signaling through pathways normally associated with positive outcomes, i.e. efficient TCR/CD3-mediated T cell activation, at least under acute conditions. Data from other groups indicate that T cell exhaustion results from chronic antigenic stimulation that extends the effector phase of T cell activation, at the expense of T cell memory. We hypothesize that signaling through the cytoplasmic tail of Tim-3 contributes to T cell exhaustion and/or the rescue of T cells in a population of exhausted T cells associated with chronic T cell activation. This hypothesis will be tested with two Specific Aims. In Aim 1, and based on our previous structure/function studies, we will generate novel mouse models for inducible knockout of Tim-3 or truncation of its cytoplasmic tail. In Aim 2, we will first determine the effects of inducible Tim-3 KO or truncation, specifically in T cells, on acute T cell responses to Listeria and LCMV; in addition, we will determine the effects of inducible, T cell-specific, KO or truncation of Tim-3 on chronic infection with LCMV-Clone 13.

摘要 T细胞耗竭是在长期暴露于抗原的条件下经常观察到的T细胞功能状态， 例如在某些慢性病毒感染和实体瘤中。然而，驱动和维持 T细胞的衰竭仍然没有得到很好的理解。许多耗尽的T细胞的表面蛋白标志物具有 现在已经鉴定出了包括跨膜蛋白PD-1和Tim-3在内的其他标志物。抗体 阻断PD-1抑制作用的药物现在已被FDA批准用于治疗黑色素瘤和一些 肺癌，还有更多的临床试验正在进行中。Tim-3作为一种 治疗目标正在取得进展，但落后于其他目标，包括PD-1等。 尽管大量相关证据表明Tim-3表达与T细胞功能障碍有关， 尽管Tim-3在疲劳期间激活，但对Tim-3促进疲劳的机制知之甚少。 发展和/或维持衰竭。这是一个挑战，部分原因是， 已经鉴定了Tim-3的混杂配体。此外，假定的Tim-3的“阻断”抗体没有 已经彻底表征了它们对Tim-3与其各种配体的相互作用的影响。我们终于有 在多种细胞类型（包括T细胞）中提供的证据表明，Tim-3实际上可以增强早期信号传导 这就提出了一个问题，即一些Tim-3抗体是否真的可以通过 Tim-3的活性交联。因此，需要新的试剂和模型系统，其将允许 Tim-3在原代T细胞中功能的更直接定义。 与PD-1或其他T细胞活性的负调节因子不同，Tim-3不包含用于募集T细胞活性的基序。 抑制性磷酸酶。相反，我们最近的研究表明，Tim-3的表达实际上增加了信号传导， 通过通常与阳性结果相关的途径，即有效的TCR/CD 3介导的T细胞 激活，至少在急性条件下。来自其他研究组的数据表明，T细胞耗竭是由以下原因引起的： 慢性抗原刺激，其延长T细胞活化的效应期，以T细胞活化为代价。 记忆我们假设通过Tim-3的胞质尾区的信号传导有助于T细胞耗竭 和/或在与慢性T细胞活化相关的耗尽的T细胞群体中拯救T细胞。 这一假设将通过两个具体目标进行检验。在目标1中，根据我们以前的 结构/功能的研究，我们将产生新的小鼠模型诱导敲除蒂姆-3或截断 它的胞质尾部。在目标2中，我们将首先确定诱导型Tim-3 KO或截短的作用， 特别是在T细胞中，对李斯特菌和LCMV的急性T细胞反应;此外，我们将确定 诱导型T细胞特异性Tim-3的KO或截短对LCMV-克隆13慢性感染的影响。