Decoding the epigenetic landscape that delineates T cell homeostatic proliferation from uncontrolled growth”

项目摘要 T细胞耗竭的表观遗传强化是一个公认的障碍，限制了T细胞耗竭的多种模式。 癌症的免疫疗法。这项建议将调查特定的表观遗传事件， T细胞衰竭的主要特征之一; T细胞增殖潜力的降低。值得注意的是， 据报道，表观遗传调节因子DNMT3A和TET2的破坏可以保护细胞的增殖。 CD8 T细胞在嵌合抗原受体（CAR）T细胞慢性刺激和PD-1刺激的背景下的能力 1阻断介导的内源性T细胞再生。重要的是，这些基因的突变也被 与造血干细胞（HSC）的克隆扩增相关，这发生在大多数其他造血干细胞（HSC）中。 健康的老年人。这种不确定潜能的克隆性造血（CHIP）主要由突变引起 三种表观遗传调节因子（DNMT 3A、TET 2、ASXL 1）的表达。尽管DNMT3A和TET2产生了破坏， 类似T细胞表型，关键区别在于DNMT3A KO T细胞维持抗原依赖性稳态 在一些实施方案中，TET2 KO T细胞表现出过度增殖的表型，并且TET2 KO T细胞表现出过度增殖的表型。ASXL1尚未被表征，但是 我们最近确定，T细胞中ASXL1的破坏也保留了细胞的增殖潜力 在PD-1封锁的情况下我的研究计划已经做好了充分的准备， 由这些离散调节子中的每一个建立的修饰，以更好地定义分子 限制T细胞在衰竭过程中增殖潜力的机制 发展轨迹我建议检验CH相关基因破坏导致 描述记忆T细胞稳态与过度增殖状态的特定表观遗传程序。到 定义这些程序，我将追求以下目标：1）定义由CH介导的表观遗传程序- 相关的表观遗传调节剂，促进体内平衡与过度增殖状态， T细胞的抗原刺激。2)为了确定是否在幼稚与记忆人类中CH调节器的破坏 T细胞导致慢性刺激的CAR T细胞的过度增殖状态。3)为了确定T细胞是否 分离自CH相关表观遗传调节因子突变的骨髓增生异常综合征（MDS）患者 表现出与高增殖能力相一致的表观遗传程序。完成拟议的研究 将定义表观遗传检查点，其调节T细胞从不受控制的细胞生长的稳态增殖。 重要的是，成功完成这项提案将确定维持T细胞免疫的基本程序。 增殖能力，用于设计和制造下一代CAR T细胞方案。拟议 本申请中概述的职业发展和培训以及实验研究将 通过进一步建立一个新的研究项目来推进我作为临床科学家的培训， 一条通往独立的道路

PROJECT SUMMARY Epigenetic reinforcement of T cell exhaustion is a well-established barrier limiting multiple modalities of T cell- based immunotherapies for cancer. This proposal will investigate the specific epigenetic events that are coupled to one of the cardinal features of T cell exhaustion; a reduction in the T cell’s proliferative potential. Notably, disruption of the epigenetic regulators DNMT3A and TET2 has been reported to preserve the proliferative capacity of CD8 T cells in the setting of both chimeric antigen receptor (CAR) T cell chronic stimulation and PD- 1 blockade-mediated rejuvenation of endogenous T cells. Importantly, mutations in these genes have also been associated with clonal expansion of hematopoietic stem cells (HSCs) which occurs in the majority of otherwise healthy older adults. Such clonal hematopoiesis of indeterminate potential (CHIP) mainly results from mutations of three epigenetic regulators (DNMT3A, TET2, ASXL1). Despite disruption of DNMT3A and TET2 producing a similar T cell phenotype, a critical distinction is that DNMT3A KO T cells maintain antigen dependent homeostatic proliferation and TET2 KO T cells exhibit a hyperproliferative phenotype. ASXL1 has yet to be characterized, but we have recently determined that disruption of ASXL1 in T cells also preserves the cell’s proliferative potential in a PD-1 blockade setting. My research program is now well-poised to dissect the specific epigenetic modifications that are established by each of these discrete regulators to better define the molecular mechanism limiting the proliferative potential of T cells as they progress down the exhaustion developmental trajectory. I propose to test the hypothesis that CH-associated gene disruptions result in specific epigenetic programs that delineate memory T cell homeostasis versus a hyperproliferative state. To define these programs, I will pursue the following aims; 1) To define epigenetic programs mediated by CH- associated epigenetic regulators that promote a homeostatic versus hyperproliferative state during persistent antigen stimulation of T cells. 2) To determine if disruption of CH-regulators among naïve versus memory human T cells results in a hyperproliferative state in chronically stimulated CAR T cells. 3) To identify whether T cells isolated from myelodysplastic syndrome (MDS) patients with mutations in CH-associated epigenetic regulators exhibit epigenetic programs consistent with heightened proliferative ability. Completion of the proposed studies will define the epigenetic checkpoint(s) regulating T cell homeostatic proliferation from uncontrolled cell growth. Importantly, successful completion of this proposal will define the underlying programs that sustain T cell proliferative capacity for the design and manufacturing of next generation CAR T cell protocols. The proposed career development and training outlined in this application, in conjunction with the experimental studies, will advance my training as a clinician scientist by further establishing a novel research program that will put me on a path to independence.