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

Theiler小鼠脑脊髓炎病毒（TMEV）是一种可靠的实验小鼠模型，用于研究嗜神经病毒诱导的神经退行性过程和癫痫发作。抗原提呈细胞（APC）在感染的C57 BL/6小鼠中引起神经炎症和神经元损伤。激活和抑制C型凝集素受体（CLR）是APC上的模式识别受体，其在不同感染性疾病中严格控制免疫稳态和保护性免疫;然而，它们在TMEV感染中的功能仍然未确定。基于CLRs激活失调导致脑免疫病理学和神经变性的假设，计划中的项目旨在详细分析CLRs在TMEV感染的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、Clec-12 a、Dectin-1）和衔接蛋白CARD 9的功能。将使用CLR-Fc融合蛋白文库和CCR 4报告细胞系鉴定病毒和宿主特异性配体。为了分析感染后CLR介导的对APC的效应子功能，将通过病毒和/或宿主特异性配体体外刺激来源于野生型、CARD 9-/-和CARD 9-/-小鼠的树突细胞、巨噬细胞和小胶质细胞。将使用敲除小鼠品系进行动物感染实验以确定DCIR、Clec-12 a、Dectin-1和CARD 9介导的对神经炎症和病理学的影响。将在CD 11b-白喉毒素受体（DTR）和CD 11 c-DTR转基因的混合骨髓嵌合小鼠和相应的BALB/c小鼠系中分析TMEV模型中表达CLR的APC群体在免疫调节和发病机制中的作用。结果将有助于了解病毒性脑炎神经保护和变性起始的潜在机制，并将详细了解中枢神经系统感染性疾病中先天免疫的调节。

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.