肠道菌群失调与系统性红斑狼疮发病的相关性研究

Previous studies have shown that imbalance of Th17 / Treg cells is related to the onset of systemic lupus erythematosus (SLE), and present studies found that the intestinal flora imbalance shall cause immune abnormalities. This research presumes that: the intestinal flora disturbance may result in abnormal metabolic product content, affect Th17 / Treg cells balance and bring about abnormal expression of inflammatory cytokines, which play an important role in the onset of SLE. To prove the hypothesis, the project shall take new SLE patients as research objects and adopt case-control study method to compare the differences of the structure, abundance and diversity of intestinal flora and flora metabolite contents of short chain fatty acids (SCFAs) between SLE patients and the control group, analyze the relationship between the change of the structure, abundance and diversity of intestinal flora and SLE patients’ disease activity and clinical features based on the established epidemiology field high throughput sequencing and GC/MS. The project will also analyze the relationship between the change of structure, abundance and diversity of intestinal flora and SCFAs content, and Th17 and Treg cells and its related association inflammatory cytokines through flow cytometry and ELISA technology. This research shall help further reveal the pathogenesis of SLE from a new point of view and provide scientific proof for discovery of new prevention strategy.

以往研究表明Th17/Treg失衡与系统性红斑狼疮（SLE）发病相关，目前研究发现Th17/Treg平衡受肠道菌群的调节。本课题假设：肠道菌群失调可能通过引起代谢产物含量异常，打破Th17/Treg和促炎/抗炎细胞因子平衡，进而导致SLE的发生、发展。为验证假设，本课题拟在已建立的SLE流行病学现场基础上，以新发病例为研究对象，采用病例对照设计，利用高通量测序及气相色谱质谱联用技术，比较SLE患者与对照肠道菌群结构、丰度和多样性及菌群代谢产物短链脂肪酸（SCFAs）含量的差异，分析肠道菌群结构、丰度和多样性及SCFAs含量变化与SLE患者疾病活动度及临床特征的关联。同时利用流式细胞及ELISA技术，进一步探讨肠道菌群结构、丰度和多样性及SCFAs含量变化与SLE患者Th17/Treg和促炎/抗炎细胞因子失衡的关联。本课题将从一个新角度探索SLE的发病机制，为提出可能的防治策略提供科学依据。

SLE是一种以全身炎症免疫功能紊乱为特征的疾病，该病病因复杂，确定关键致病环节是SLE研究聚焦的前沿问题。申请人前期提出科学假设：肠道菌群失调可能通过引起代谢产物含量异常，打破Th17/Treg和促炎/抗炎细胞因子平衡，进而导致SLE的发生发展。为验证假设，申请人团队经过三年的流行病学调查和生物样本收集，以100名新发病例和100名健康对照为研究对象，采用病例对照设计，比较SLE患者与对照肠道菌群结构、丰度和多样性差异，结果表明，SLE患者肠道菌群alpha多样性下降（P<0.05），SLE与健康对照间beta多样性存在显著差异（均有P=0.001）。与健康对照相比，在门水平上，SLE患者肠道中的变形菌、拟杆菌和梭杆菌门丰度增加，厚壁菌、放线菌门丰度下降；在属水平上，包括多种短链脂肪酸代谢相关菌属（如粪杆菌、杆菌、罗斯伯里氏菌、Subdoligranulum、瘤胃球菌、链球菌等）在SLE患者中显著减少；在种水平上，Faecalibacterium prausnitzii、Roseburia inulinivorans以及拟杆菌属、丁酸弧菌属下物种等在SLE患者中显著减少（均有P<0.05）。与健康对照相比，SLE患者粪便中的乙酸和丁酸浓度降低（均有P<0.05）。Treg和Th17细胞相关细胞因子IL10、IL17A、IL21表达水平在SLE患者中显著增加（P<0.001, P=0.028, P=0.033）。梭杆菌门与IL17A、IL21表达呈正相关（r=0.350, P=0.036; r=0.373, P=0.042），瘤胃梭菌属与IL21表达呈负相关（r=-0.389，P=0.033），肠球菌属与IL21表达呈正相关（r=0.367，P=0.046）。综上所述，本课题已完成既定研究目标，从一个新角度探索了SLE的发病机制，为提出可能的防治策略提供了科学依据。