Enhancing Treg Therapeutic Efficacy in GVHD

增强 GVHD 中 Treg 的治疗功效

• 批准号: 8837683
• 负责人: Bruce R Blazar
• 金额: $ 42.35万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-15 至 2018-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8837683
• 关键词: Acute; Adoptive Transfer; Antibodies; Antigen-Presenting Cells; Antigens; Autoimmunity; Biochemical; Biological; Biological Preservation; Biology; Blood; Buffers; Bypass; Cells; Chimera organism; Clinical Trials; Colitis; Complex; DNA; Dependency; Disease model; Distal; Dose; Event; Generations; Genetic Transcription; Goals; Graft Rejection; Health; Hematopoietic stem cells; Human; IL2 gene; Immune; Immune response; Immune system; Immunosuppression; In Vitro; Incidence; Inflammatory; Intercellular Junctions; Interleukin-2; Intestines; Life; Mass Spectrum Analysis; Mediating; Molecular; Movement; Mus; Mutant Strains Mice; Organ; Pathway interactions; Patients; Phase; Phosphorylation; Play; Protein Kinase C; Proteins; Proteomics; Recruitment Activity; Regulatory T-Lymphocyte; Rodent; Rodent Model; Route; STAT5B gene; Signal Pathway; Signal Transduction; Solid; T-Cell Receptor; T-Lymphocyte; Testing; Toxic effect; Transgenic Mice; Transplant Recipients; Transplantation; Treatment Efficacy; Viral; Viral Tumor Antigens; base; clinical application; disorder prevention; graft vs host disease; hematopoietic cell transplantation; immune function; immunological synapse; improved; in vivo; inhibitor/antagonist; insight; leukemia; member; novel; novel strategies; pathogen; peripheral blood; pre-clinical; prevent; protein complex; response; small molecule; tumor

DESCRIPTION (provided by applicant): Thymic-derived CD4+25+FoxP3+ regulatory T cells (Tregs) are required to suppress autoimmunity and limit foreign antigen responses. Our first-in-human phase I dose escalation trial of ex vivo expanded human Tregs proved efficacious in significantly reducing the incidence of acute graft-vs-host disease (GVHD). Two major limitations to uniform efficacy were identified: Problem 1 (achieving optimal suppression): The %suppression was variable. Problem 2 (maintaining adequate Treg:Teffector ratios): Ratios of 1:5.5 achieved were well below the desired ratios of e1:1 need for GVHD prevention in mice; no Tregs were detected by 2 weeks post-transfer. Aim 1 will focus on Problem 1. PKC-q coordinates immune function, which results in its movement to the immunological synapse (direct contact point between T cell and antigen-presenting cell) in Teffectors but not Tregs. PKC-q deficient murine Teffectors are unable to cause GVHD but can retain anti-tumor and anti- pathogen responses. Tregs treated with a small molecule PKC-q inhibitor had augmented suppressor function and were more effective in suppressing murine colitis. In aim 1, focused on Problem 1, we will use small molecule PKC-q inhibitors in vitro or in vivo to test the hypotheses that murine and human Treg potency for GVHD suppression is limited by movement of PKC-q into the immunological synapse. In aim 2, focused on Problem 2, we will test the hypothesis that sustained IL-2R signaling pathways will provide a PKC- q independent route to Treg expansion and GVHD suppression. We will use 3 strategies to improve Treg mediated GVHD suppression: (a) administer IL-2/anti-IL2 antibody complexes or low dose IL-2 to preferentially expand murine and human Tregs vs Teffectors; (b) Constitutively express STAT5b in murine and human Tregs based upon our findings that constitutive STAT5b promotes murine Treg generation, proliferation and function including GVHD suppression, bypassing the need for IL-2, present in limiting amounts in vivo; and (c) increase b-catenin signaling using a GSK-3b inhibitor in vitro or expressing a stabilized b-catenin in human Tregs since stabilized b-catenin reduces Treg dependency upon IL-2 and provides a marked enhancement of murine Treg survival and efficacy in preventing colitis. In aim 3, we will select the best 1-2 approaches, derived from studies in aims 1 and 2, for testing in preclinical GVHD models for the preservation of beneficial immune responses later post-transplant. Long-term chimeras that do not succumb to GVHD lethality, as a result of preferred approaches developed aims 1 and 2, will be challenged with leukemia cells or bacterial or viral pathogens to quantify the extent to which the immune system can respond to life-threatening complications post-transplant.

描述（由申请人提供）：胸腺来源的 CD4+25+FoxP3+ 调节性 T 细胞 (Treg) 需要抑制自身免疫并限制外来抗原反应。我们对离体扩增的人类 Tregs 进行的首次人体 I 期剂量递增试验被证明可以有效显着降低急性移植物抗宿主病 (GVHD) 的发生率。确定了统一功效的两个主要限制： 问题 1（实现最佳抑制）：抑制百分比是可变的。问题 2（维持足够的 Treg:Teffector 比率）：达到的 1:5.5 比率远低于预防小鼠 GVHD 所需的 e1:1 比率；转移后 2 周未检测到 Tregs。目标 1 将重点关注问题 1。PKC-q 协调免疫功能，导致其移动到 T 效应器中的免疫突触（T 细胞和抗原呈递细胞之间的直接接触点），而不是 Tregs。 PKC-q 缺陷的小鼠 T 效应子不能引起 GVHD，但可以保留抗肿瘤和抗病原体反应。用小分子 PKC-q 抑制剂治疗的 Tregs 增强了抑制功能，并且在抑制小鼠结肠炎方面更有效。在目标 1 中，重点关注问题 1，我们将在体外或体内使用小分子 PKC-q 抑制剂来测试以下假设：小鼠和人类 Treg 抑制 GVHD 的效力受到 PKC-q 进入免疫突触的运动的限制。在目标 2 中，重点关注问题 2，我们将测试以下假设：持续的 IL-2R 信号通路将为 Treg 扩增和 GVHD 抑制提供独立于 PKC-q 的途径。我们将使用 3 种策略来改善 Treg 介导的 GVHD 抑制：(a) 施用 IL-2/抗 IL2 抗体复合物或低剂量 IL-2，以优先扩增小鼠和人类 Tregs 与 Teffector； (b) 根据我们的发现，组成型 STAT5b 促进小鼠 Treg 生成、增殖和功能，包括 GVHD 抑制，从而绕过对体内限量存在的 IL-2 的需要，在小鼠和人类 Tregs 中组成型表达 STAT5b； (c) 在体外使用 GSK-3b 抑制剂增强 β-连环蛋白信号传导，或 在人Treg中表达稳定的b-连环蛋白，因为稳定的b-连环蛋白减少了Treg对IL-2的依赖性，并显着增强了小鼠Treg的存活率和预防结肠炎的功效。在目标 3 中，我们将选择源自目标 1 和 2 研究的最佳 1-2 种方法，用于在临床前 GVHD 模型中进行测试，以在移植后保留有益的免疫反应。由于目标 1 和 2 开发的首选方法，不屈服于 GVHD 致死性的长期嵌合体将受到白血病细胞或细菌或病毒病原体的挑战，以量化免疫系统对移植后危及生命的并发症的反应程度。