干扰素调节因子8通过RORγt通路调控Th17细胞分化在白塞病发病机制中的作用

The pathogenesis of Behçet's disease (BD) is still unknown. Recent studies indicated that IRF8 may be a risk factor for BD. Single nucleotide polymorphism (SNP) of IRF8 is associated with ocular and intestinal BD. IRF8 inhibits Th17 cell differentiation via binding to RORγt, thus reduce the inflammatory response induced by Th17 cell. Our previous study has showed Th17 cells differentiation and IL-17, IL-23 expression were significantly higher in the peripheral blood monocyte cells (PBMCs) of BD patients and mouse models compared with health control. The peripheral blood leukocyte count and DAIBD score were positively correlated with IL-17 and IL-23 level, and gradually decreased after the therapeutic interventions. This study plans to detect the expression of IRF8, Th17 cells, IL-17, IL-17F and IL-22 level in BD patients and mouse model. The IRF8 single nucleotide polymorphism of ocular BD and intestinal BD will be analyzed. Adenovirus transfection will be applied to regulate the expression of IRF8 and the differentiation of Th17 cell in vitro. To detect whether the inhibiting effect of IRF8 on Th17 cell differentiation was achieved by binding to RORγt, co-immunoprecipitation will be performed in 293T cells. The aim of this study is to elucidate the role and mechanism of IRF8/RORγt signaling pathway which regulating Th17 cell differentiation in the process of BD inflammatory.

白塞病（BD）发病机制不明。近年研究提示，干扰素调节因子8（IRF8）可能为BD风险基因之一，IRF8单核苷酸多态性与BD葡萄膜炎和肠溃疡显著相关，IRF8可能通过结合RORγt抑制Th17细胞分化及其介导的炎症反应。本课题组前期发现，与健康对照比较，BD病人和小鼠模型外周血Th17细胞和相关IL-17、IL-23高表达，且与外周血白细胞计数、DAIBD评分呈正相关，经治疗干预后均呈下降趋势。本研究拟检测小鼠模型和BD患者IRF8表达、Th17细胞和IL-17、IL-17F、IL-22；分析眼BD和肠BD的IRF8单核苷酸多态性；通过腺病毒转染CD4+T细胞研究IRF8表达和Th17细胞分化调节，用免疫共沉淀技术在293T细胞中探讨IRF8通过结合RORγt调控Th17细胞分化。本研究旨在阐明IRF8/RORγt信号通路调控Th17细胞分化在BD炎症调节中的作用机制。

白塞病（Behçet Disease，BD）是一种病因不明的慢性、复发性变异性血管炎。临床上以口腔溃疡、外阴溃疡，皮肤黏膜病变为主要特征，可累及眼、胃肠、神经、血管、心脏、关节和血液等系统器官。因其累及系统之多，鉴别诊断复杂，目前在临床上仍有巨大挑战。本课题组通过建立白塞病数据，总结了BD患者的临床特征及实验室差异，将白塞病分为8型，包括：肠白塞，眼白塞，神经白塞，皮肤黏膜型白塞，关节型白塞，血液型白塞、心脏白塞以及血管型白塞。同时，收集临床病人外周血标本后，对提取的外周血中的单个核和淋巴细胞分析发现，相比健康对照组来说，BD患者淋巴细胞中IRF8蛋白表达水平降低，且IRF8可以通过RORγt通路抑制Th17细胞的分化。同时发现，不同类型的BD患者的表观遗传学具有差异，例如，肠溃疡患者血浆外泌体中的 miR-141-3p下调介导肠上皮细胞焦亡。在转录组水平上，肠上皮细胞通过TNF-α刺激或与外周血的单个核和淋巴细胞共培养会导致IFI16过表达引起肠上皮细胞凋亡。本研究为揭示BD的发病机制提供了新的方向，也为疾病的精准治疗提供了重要理论依据。