Molecular Mechanisms of TOX-mediated Programming of CD8 T Cell Exhaustion

项目摘要 对病毒感染和肿瘤的CD 8 T细胞应答显著促进免疫应答， 决定了这些病理的临床结果。CD 8 T细胞应答的功能完整性取决于 CD 8效应子（Teff）和记忆（Teff）群体的特征性质。然而，在慢性 病毒感染和癌症，没有清除的抗原持久性排除了有效的Teff和Teff 相反，CD 8 T细胞分化偏向于表观遗传学上不同的“耗尽”谱系， （德克萨斯州）。特克斯表现出进行性功能障碍和效应器特性、增殖能力和记忆的丧失 潜在的，以及PD 1和多种其他抑制性受体（IR）的共表达的持续增加。 探究启动和维持特克斯表观遗传状态的基本机制是至关重要的 重要的是了解特克斯生物学和确定战略，以选择性地靶向或调节特克斯。 然而，该领域通常缺乏详细的机械理解纺织品特定的表观遗传过程。在 慢性感染期间的衰竭模型和功能失调的肿瘤特异性T细胞，转录因子 TOX对于Tex发育的起始、抑制终末Teff分化和增强Tex的表达是必需的。 对特克斯血统的表观遗传承诺。这项建议旨在确定和询问机械细节 Tex通过TOX调节，这将是开始开发免疫治疗方法所必需的， 表观遗传学重新编程Tex并改善免疫治疗的临床结果。 TOX用于发挥其作用的分子交易在很大程度上仍然未知。了解细节 由于缺乏其N-和C-末端结构域（“NTD”）的功能表征， 和“CTD”）。我的初步数据表明，在体外， TOX NTD或CTD足以消除表面PD 1表达的增加， 特征性地由全长（“FL”）TOX驱动，表明这些结构域的重要的、至今未知的作用。 这一建议的核心假设是，TOX活动的独特特征可归因于其N- vs. C-末端结构域和NTD-或CTD-特异性扰动将能够选择性调节 特克斯对慢性病毒感染的反应。该提案通过询问TOX的特征来检验这一假设。 在Pdcd 1基因座（编码PD 1）的相互作用和结构域水平的功能，通过定义的程度， 通过定义NTD和CTD计划如何在全球范围内发挥作用，NTD和CTD在各自的纺织品特定角色中表现出全球差异。 Tex表观遗传状态，并通过确定NTD和CTD介导的蛋白质相互作用TOX使用， 调节Tex转录。因此，这一建议将推进分子如何 调节耗竭的过程可以被操纵以改善慢性病毒感染期间的CD 8 T细胞应答。 感染和癌症。

PROJECT SUMMARY CD8 T cell responses to viral infections and tumors contribute significantly to the immune responses that dictate the clinical outcomes of such pathologies. The functional integrity of CD8 T cell responses depends on the characteristic properties of CD8 effector (Teff) and memory (Tmem) populations. However, during chronic viral infections and cancer, antigen persistence without clearance precludes effective Teff and Tmem development, instead biasing CD8 T cell differentiation towards an epigenetically distinct “exhausted” lineage (Tex). Tex exhibit progressive dysfunction and loss of effector properties, proliferation capacity, and memory potential, as well as a sustained increase in co-expression of PD1 and multiple other inhibitory receptors (IRs). Interrogating the fundamental mechanisms that initiate and maintain the Tex epigenetic state is of central importance to understanding Tex biology and identifying strategies to selectively target or modulate Tex. However, the field generally lacks a detailed mechanistic understanding of Tex-specific epigenetic processes. In models of exhaustion during chronic infection and of dysfunctional tumor-specific T cells, the transcription factor TOX is essential for the initiation of Tex development, repressing terminal Teff differentiation and potentiating epigenetic commitment to the Tex lineage. This proposal seeks to identify and interrogate the mechanistic details of Tex regulation by TOX that would be required to begin developing immunotherapy approaches to epigenetically reprogram Tex and improve immunotherapy clinical outcomes. The molecular transactions TOX employs to exert its effects remain largely unknown. Understanding the details of TOX activity remains limited by a lack of functional characterization of its N- and C-terminal domains (“NTD” and “CTD”) in relation to its HMG-box DNA binding domain. My preliminary data demonstrate in vitro that loss of either the TOX NTD or CTD is sufficient to abrogate the increase in surface PD1 expression that is characteristically driven by full-length (“FL”) TOX, suggesting important, as yet unknown roles for these domains. The central hypothesis of this proposal is that distinct features of TOX activity are attributable to its N- vs. C-terminal domains and that NTD- or CTD-specific perturbations will enable selective modulation of Tex responses to chronic viral infection. This proposal tests this hypothesis by interrogating features of TOX’s interactions and domain-level function at the Pdcd1 locus (encoding PD1), by defining the extent to which the NTD and CTD exhibit global differences in their Tex-specific roles, by defining how the NTD and CTD program the Tex epigenetic state, and by determining which NTD- and CTD-mediated protein interactions TOX uses to regulate Tex transcription. This proposal will thus advance fundamental knowledge of how the molecular processes regulating exhaustion may be manipulated to improve CD8 T cell responses during chronic viral infections and cancer.