Tfr细胞调控Tfh细胞介导的B细胞分化在狼疮肾炎发病中的作用机制研究

Over activation of self-reactive B cell and production of autoantibody is one of the SLE characteristics. T follicular helper cells (Tfh) are the most important helper T cells that induce B cell differentiation and antibody production. Recent study found that T follicular regulatory cells (Tfr) cells play a negative regulatory role in inducing B cell maturation. In preliminary study, we found that proportion of Tfr in the peripheral blood of patients with lupus nephritis (LN) was significantly lower than that of healthy people and was negatively correlated with serum autoantibody level and disease activity. This study aims to: (1) investigate the relationship between the Tfr / Tfh cells as well as their different subgroups and the expression of B cell activation-related cytokines and the degree of disease activity in LN patients. (2) explore the regulatory role of Tfr cell on Tfh/B cell differentiation and proliferation, autoantibody production, cytokine expression by in vitro co-culture of Tfr / Tfh / B cells; (3) investigate the therapeutic effect of adoptive transfer of Tfr cells on acquired immunization and renal injury in lupus mice. The completion of this study will help to explore new targets for the treatment of LN.

自身反应性B细胞过度活化及自身抗体的产生是SLE特征之一。滤泡辅助性T细胞(Tfh)是诱导B细胞分化并且产生抗体的最重要的辅助性T细胞。最新研究发现滤泡调节性T细胞(Tfr)在Tfh细胞诱导的B细胞成熟过程中发挥负性调节作用。本研究在我们预实验发现狼疮肾炎(LN)患者外周血Tfr比例较健康人显著下降，并且与血清中自身抗体水平及疾病活动度呈负相关的基础上，探讨Tfr在LN发病中的作用。本课题拟通过：(1)分析LN患者中Tfr、Tfh细胞及其不同亚群比例与B细胞活化相关细胞因子表达及疾病活动程度的相关关系；(2)体外共培养Tfr/Tfh/B细胞探讨Tfr对Tfh及B细胞分化增殖、自身抗体生成、细胞因子表达的调控作用及相关分子机制；(3)体内过继免疫治疗探索Tfr细胞对狼疮小鼠适应性免疫的影响及对肾损害的治疗作用。本课题的完成有助于探索LN治疗新靶点。

大量自身抗体的产生是系统性红斑狼疮（SLE）特征之一。滤泡辅助性T细胞(Tfh)主要功能是促进B细胞增殖分化和产生抗体。滤泡调节性T细胞(Tfr)可以拮抗Tfh细胞功能.它们之间的平衡对维持免疫稳态至关重要。主要研究内容包括:(1)分析LN患者中Tfr、Tfh细胞及其不同亚群比例与B细胞活化相关细胞因子表达及疾病活动关系;(2)SLE患者外周血Tfh细胞NLRP3炎性小体活化情况及其与疾病活动关系;(3)用选择性NLRP3抑制剂对狼疮小鼠进行体内干预,观察对Tfh细胞分化增殖影响;(4)固有淋巴细胞（ILC）亚群在SLE患者中比例及与其疾病活动相关性;(5)NLRP炎性小体活化在小鼠急性肺损伤（ALI）中的致病作用及机制。研究发现:(1)SLE患者外周血Tfh/Tfr细胞比值高于健康对照。Tfh/Tfr比例与血清抗dsDNA抗体浓度、IL-21水平及SLE疾病活动度相关。复发的SLE患者治疗后Tfh/Tfr比值下降;(2)SLE患者外周血Tfh 细胞NLRP3炎性小体明显活化，且NLRP3炎性小体活化程度与疾病活动度正相关;(3)用选择性NLRP3抑制剂MCC950治疗后，狼疮小鼠脾脏Tfh细胞增生分化受抑制、对B细胞辅助作用及自身抗体产生减少、肾损伤减轻;(4)SLE患者体内ILC数目明显增多并伴有亚群的改变，中重度疾病活动度的SLE患者ILC1比例明显升高而ILC2和ILC3比例则下降;(5)ALI小鼠肺组织坏死性凋亡途径和NLRP炎性小体通路均明显活化,利用RIP3选择性抑制剂GSK872阻断坏死性凋亡途径后NLRP炎性小体通路活化亦受到明显抑制，ALI肺损害随之减轻。体外实验发现LPS刺激下THP-1细胞中检测到NLRP和RIP3相互作用，并且可以被GSK872所抑制。本课题的完成有助于探索将Tfh细胞和NLRP炎症体作为LN治疗新靶点。