Immunoregulatory Mechanisms to Combat CNS Pathology During Infection

目的：新生隐球菌是引起中枢神经系统（CNS）相关死亡的最重要的真菌病原体 和发病率。虽然CM通常被认为是由免疫力低下引起的疾病，但证据表明， 积累了丰富的宿主免疫应答显着有助于CM的发病机制。本 最后，我们建立了一个小鼠CM模型，该模型再现了CM中炎性CNS损伤的主要特征 患者，发现由超Th 1极化T细胞驱动的旺盛的CNS炎症， 炎性单核细胞，促进严重的免疫病理学与神经恶化。 调节性T细胞（Regulatory T cells，Tcells）是这一免疫调节网络的重要组成部分， 与人类患者中CM的炎性并发症有关。我们已发表和未发表的初步报告 现在的数据支持Treg在限制肿瘤细胞内的病理性炎症中发挥关键作用。 隐球菌感染中枢神经系统。我们的初步数据进一步表明Treg特异性表达趋化因子， 受体CCR 8和Treg募集动力学是通过上调CCR 8配体趋化因子 CCL 1，支持CCL 1/CCR 8轴在介导Treg的CNS迁移中的重要性。我们证明了 在CNS内的所有细胞群中，Treg是免疫调节剂的主要（如果不是唯一的）产生者， 调节细胞因子IL-10和双调蛋白（Areg），已知促进伤口愈合和组织修复的因子。 假设：假设CCL 1/CCR 8轴募集的Treg保护免受严重的CNS损伤， 通过产生IL-10和Areg以及基于Treg免疫疗法，患有CM的小鼠随后的死亡率 将降低CM小鼠的发病率和死亡率。为了检验这一假设的不同部分，我们将： 目标1。为了证明CCR 8募集的Treg保护CM中的脑免受炎症病理学的影响， 1.a.确定Treg是否限制CM期间过度的CNS炎症，特别是减少病理因素 中枢神经系统的宿主反应 1.b.确定Treg是否以及如何减少受CM折磨的大脑中的神经病理过程 1.c.证明了CCR 8轴对CNS Treg积累的依赖性及其在CM期间的功能。 目的2：明确Treg在CM中的治疗作用 2.a.表明通过IL-2免疫复合物治疗的Treg增强保护小鼠免于致命性CM 病理 2.b.确定CCR 8+与CCR 8- Treg过继转移是否保护小鼠免于致命性CM病理 目的3：确定Treg限制CNS炎症和促进CNS炎症的机制。 CM期间的神经修复 3.a.确定Treg衍生的IL-10是否是限制CM期间病理性CNS炎症所必需的 3.b.定义Treg衍生的Areg是否在CM期间促进神经修复。 研究计划和方法：本研究将利用我们建立的CM小鼠模型， 重现了C.新生儿CNS感染。 我们将操纵Treg系统（去除或扩大T reg反应，以确定它们是否会恶化或恶化）。 分别改善CM动物状况）。我们还将进行一系列的过继转移实验 以确定其施用是否会减轻症状。最后，我们将使用T- 细胞限制性IL-10 KO小鼠和T细胞限制性双调蛋白KO小鼠，以确定分子水平 它们的抗炎和CNS保护作用的机制，以及它们如何影响 CM中的CNS病理学。总的来说，这些研究将提供关于T细胞介导的病理学的重要见解， 在中枢神经系统真菌感染过程中，Tendon如何对抗这一过程，这一研究将可能发现新的 生物标志物或治疗机会。

Objectives: Cryptococcus neoformans is the most important fungal pathogen causing CNS-related mortality and morbidity world-wide. Although CM is generally viewed as a disease caused by weak immunity, evidence accumulates that exuberant host immune responses significantly contribute to the pathogenesis of CM. To this end, we developed a murine model of CM that reproduces major features of inflammatory CNS injury in CM patients and found that the exuberant CNS inflammation, driven by ultra Th1-polarized T cells and inflammatory monocytes, promotes severe immunopathology with neurological deterioration. Regulatory T cells (Tregs) are the crucial component of this immunoregulatory network, and their dysfunction is linked to inflammatory complications of CM in human patients. Our published and unpublished Preliminary Data now support that Treg play crucial roles in limiting the pathological inflammation within the Cryptococcus-infected CNS. Our preliminary data further show that Treg specifically express chemokine receptor CCR8 and that Treg-recruitment kinetics is paralleled by the upregulation of CCR8 ligand chemokine CCL1, supporting the importance of the CCL1/CCR8 axis in mediating CNS migration of Treg. We show that among all cellular populations within the CNS, Treg are the major, if not sole producer of the immune- regulatory cytokine IL-10 and Amphiregulin (Areg), factor known to promote wound healing and tissue repair. Hypothesis: Hypothesis that CCL1/CCR8-axis-recruited Treg protect against severe CNS damage and subsequent mortality in mice with CM via production of IL-10 and Areg and that Treg-based immunotherapies will reduce morbidity and mortality in mice with CM. To test distinct parts of this hypothesis we will: Aim 1. To demonstrate that CCR8-recruited Treg protect the brain from inflammatory pathology in CM 1.a. determine if Treg limit excessive CNS inflammation during CM, especially reducing pathological elements of the CNS host response 1.b. define whether and how Treg reduce neuropathological processes in the CM-afflicted brain 1.c. demonstrate the dependence of the CCR8 axis for CNS Treg accumulation and their function during CM. Aim 2: To define the therapeutic effects of Treg in CM 2.a. demonstrate that Treg enhancement by IL-2 immune complex therapy protects mice from fatal CM pathology 2.b. determine if CCR8+ versus CCR8- Treg adoptive transfer protects mice from fatal CM pathology Aim 3: To determine the mechanisms by which Treg limit CNS inflammation and promote neurological repair during CM 3.a. determine if Treg-derived IL-10 is required for limiting pathological CNS inflammation during CM 3.b. define whether Treg-derived Areg promotes neurological repair during CM. Research Plan and Methods: This proposal will use our established mouse model of CM, which accurately recapitulates severe paradoxical immune responses experienced by patients with C. neoformans CNS infection. We will manipulate Treg system (remove or expand T reg responses, to determine if they would worsen or improve condition of CM animals, respectively). We will also perform a series of adoptive transfer experiments with isolated Tregs to determine if their administration would alleviate the symptoms. Finally, we will use T- cell restricted IL-10 KO mice and T-cell-restricted Amphiregulin KO mice to determine the molecular mechanism of their anti-inflammatory and CNS protective effect and how they will affect different aspects of CNS pathology in CM. Overall, these studies will provide significant insight on T cell mediated pathology and how Tregs oppose this process during fungal CNS infections, that down the road will likely identify new biomarkers or therapeutic opportunities.