C-type lectin receptor-mediated effects on neurodegeneration and immunopathology in the brain following neurotropic virus infection

泰勒氏小鼠脑脊髓炎病毒（TMEV）是研究嗜神经病毒引起的神经退行性过程和癫痫发作的可靠实验小鼠模型。抗原呈递细胞（APC）是C57BL/6感染小鼠神经炎症和神经元损伤的起始机制。激活和抑制c型凝集素受体（CLRs）是APC上的模式识别受体，在不同感染性疾病中密切控制免疫稳态和保护性免疫；然而，它们在TMEV感染中的作用尚未确定。基于CLR激活失调导致脑免疫病理和神经退行性变的假设，计划项目旨在详细分析CLR在TMEV感染神经发病机制中的作用。因此，(1)将鉴定病毒和/或宿主特异性配体，(2)将进行机制研究，以确定tmev感染小鼠中clr （DCIR, ecc -12a, Dectin-1）和适配器蛋白CARD9的功能。病毒和宿主特异性配体将使用CLR- fc融合蛋白文库和CLR报告细胞系进行鉴定。为了分析感染后CLR介导的效应对APC的作用，将在体外用病毒和/或宿主特异性配体刺激野生型、CLR-/-和CARD9-/-小鼠的树突状细胞、巨噬细胞和小胶质细胞。动物感染实验将通过敲除小鼠品系来确定DCIR-、ecc -12a-、Dectin-1-和card9介导的对神经炎症和病理的影响。在cd11b -白喉毒素受体（DTR）和CD11c-DTR转基因混合骨髓嵌合小鼠以及各自的CLR-/-小鼠系中，分析表达CLR- APC群体在TMEV模型中免疫调节和发病机制中的作用。研究结果将有助于了解病毒性脑炎的神经保护和变性起始的潜在机制，并将为中枢神经系统感染性疾病的先天免疫调节提供详细的见解。

The Theiler's murine encephalomyelitis virus (TMEV) represents a reliable experimental mouse model to study neurodegenerative processes and seizures induced by neurotropic viruses. Antigen presenting cells (APC) account for the initiation of neuroinflammation and neuronal damage in infected C57BL/6 mice. Activating and inhibiting C-type lectin receptors (CLRs) are pattern recognition receptors on APC that tightly control immune homeostasis and protective immunity in different infectious disorders; however, their function in TMEV infection remains as yet undetermined. Based on the hypothesis that dysregulated CLR activation causes brain immunopathology and neurodegeneration, the planned project aims to analyze the effect of CLRs in the neuropathogenesis of TMEV infection in detail. Therefore, (1) viral and/or host specific ligands will be identified and (2) mechanistic studies will be performed to determine the function of CLRs (DCIR, Clec-12a, Dectin-1) and the adaptor protein CARD9 in TMEV-infected mice. Viral and host specific ligands will be identified using a CLR-Fc fusion protein library and CLR reporter cell lines. For analyses of CLR-mediated effector functions on APC upon infection, dendritic cells, macrophages and microglia derived from wild type, CLR-/- and CARD9-/- mice will be stimulated in vitro by viral and/or host specific ligands. Animal infection experiments will be performed to determine DCIR-, Clec-12a-, Dectin-1- and CARD9-mediated effects on neuroinflammation and -pathology using knockout mouse strains. The role of CLR-expressing APC populations in immune regulation and pathogenesis in the TMEV model will be analyzed in mixed bone marrow chimeric mice of CD11b-diphtheria toxin receptor (DTR) and CD11c-DTR transgenic and the respective CLR-/- mouse lines. Results will help to understand the underlying mechanisms of neuroprotection and initiation of degeneration in viral encephalitis and will give detailed insights in the regulation of innate immunity in infectious disorders of the central nervous system.