Regulating Pathogen-induced Protective and Pathogenic CD8 T cells in the CNS

神经系统疾病是导致死亡和残疾的主要原因，尽管病因多样， 免疫功能障碍的共同主题。免疫系统和神经系统对这两者都有很好的调节 感知并协调对外界刺激的反应。大脑中有数十亿个神经元，但我们知道， 几乎没有关于大脑神经元如何与中枢神经系统中的免疫系统相互作用的知识。的最新进展 神经免疫学包括脑膜淋巴管的发现，免疫细胞在CNS稳态中的作用 以及CNS感染后在脑中持续存在的组织驻留记忆T细胞（Trm）的表征。我们 最近（Urban等人，Nature Immunology，2020）提供的证据表明，Trm也是在 大脑在外周免疫和感染后，这表明大脑独特的过程可能 在外周免疫后培养Trm在该器官中的持久性。然而，尚不清楚是否有特定的神经元 大脑中的通路有助于Trm的产生或在该器官中的持续存在， 影响CNS Trm的保护作用。 人类中的几种CNS疾病具有免疫学病因，T细胞被认为有助于免疫系统。 病毒性脑炎（VE）、脑型疟疾（CM）的发病机制。因此，第二个未知因素是脑 T细胞介导的CNS疾病中的神经元信号传导途径。 我们将用化学遗传学来解决这些问题。具体来说，有高度保守的神经元 在脑干内，如中缝背核（DR），它广泛地投射在整个CNS中，并在 对免疫相关信号的反应，如压力，疼痛和瘙痒。转基因B6小鼠表达SERT- cre靶向DR神经元。立体定向注射表达flox/stop设计者的腺相关病毒 受体专门激活的设计师药物（DREADD），导致表达的DREADD只在cre- 表达神经元。通过mCherry表达检测转导的表达cre的神经元，并且可以将其 操纵，这取决于它们的性质（由精确DREADD指定的激活或抑制信号）， 注射设计配体。我们已经获得了这些小鼠和病毒系统，并为我们的能力提供了证明 进行复杂的立体定位手术，并将DREADD结构传递到目标神经元。 我们将使用化学遗传学技术和我们的能力，以评估中枢神经系统免疫和免疫介导的 发病机制，以测试中央假设，脑神经元信号通路有助于 CNS Trm的产生、维持和功能以及T细胞介导的CNS疾病的结局。 具体目标1。确定DR神经元信号传导是否调节DR的产生、维持或保护。 脑功能Trm. 具体目标2。确定DR神经元信号传导是否调节CD8 T细胞介导的淋巴细胞 脉络丛脑膜炎病毒（LCMV）诱导的VE或实验性脑型疟疾（ECM）。

Neurological diseases are a leading cause of death and disability, and despite diverse etiologies, share a common theme of immunological dysfunction. The immune and nervous systems are finely tuned to both sense and orchestrate responses to external stimuli. There are billions of neurons in the brain, yet we know next to nothing about how brain neurons interface with the immune system in the CNS. Recent advances in neuroimmunology include the discovery of meningeal lymphatic, roles for immune cells in CNS homeostasis and characterization of tissue resident memory T cells (Trm) that persist in the brain after CNS infection. We recently (Urban et al, Nature Immunology, 2020) provided evidence that Trm were also generated uniquely in the brain after peripheral immunizations and infections, suggesting that processes unique to the brain may foster Trm persistence in this organ after peripheral immunization. However, it is unknown if specific neuronal pathways in the brain contribute to Trm generation or persistence in this organ and whether neuronal signaling influences protection by CNS Trm. Several CNS diseases in humans have immunological etiologies, with T cells thought contribute to the pathogenesis of viral encephalitis (VE), cerebral malaria (CM) Thus, a second unknown is the role of brain neuronal signaling pathways in T cell-mediated diseases of the CNS. We will attack these problems using chemogenetics. Specifically, there are highly conserved neurons within the brainstem, such as the dorsal raphe (DR), which project broadly throughout the CNS and activate in response to immunity-relevant signals such as stress, pain, and itch. Transgenic B6 mice expressing SERT- cre target DR neurons. Stereotaxic injection of adeno-associated viruses expressing flox/stop designer receptors exclusively activated by designer drugs (DREADD), results in expression of the DREADD only in cre- expressing neurons. Transduced cre-expressing neurons are detected by mCherry expression and can be manipulated, depending on their nature (activating or inhibitory signals specified by the precise DREADD), by injection of a designer ligand. We have obtained these mice and virus systems and provided proof of our ability to perform the sophisticated stereotaxic surgeries and deliver the DREADD constructs to the targeted neurons. We will use the chemogenetic technology and our capacity to evaluate CNS immunity and immune-mediated pathogenesis to test the central hypothesis that brain neuronal signaling pathways contribute to the generation, maintenance and function of CNS Trm and the outcome of T cell-mediated CNS diseases. Specific Aim 1. Determine if DR neuronal signaling regulates the generation, maintenance or protective function of brain Trm. Specific Aim 2. Determine if DR neuronal signaling regulates CD8 T cell-mediated lymphocytic choriomeningitis virus (LCMV) induced VE or experimental cerebral malaria (ECM).