敲除NLRP3通过增加Treg细胞减轻右旋糖酐硫酸钠盐诱导的肠道炎症

NLRP3 Deficiency Alleviates DSS Induced Intestinal Inflammation via Increasing Treg Cells

目的探讨NLRP3炎症小体在急性结肠炎中的作用。方法通过饲喂右旋糖酐硫酸钠盐(DSS)在野生型(WT)与NLRP3缺陷型(NLRP3^-/-)小鼠中建立炎症性肠病(IBD)模型。而后将小鼠分为4组:WT对照组、WT肠炎组、NLRP3^-/-对照组和NLRP3^-/-肠炎组。DSS饲喂期间记录小鼠体重,7 d后处死小鼠,收集其血清、肠系膜淋巴结(mLN)、派伊尔结(PPs)、脾脏以及结肠等标本;苏木精-伊红染色、TUNEL染色评估其炎症损伤以及细胞凋亡情况;流式细胞术检测各组小鼠T、B淋巴细胞比例差异;ELISA检测血清细胞因子水平;Western blot检测各组小鼠结肠中细胞因子表达水平;体外诱导初始CD4+T细胞向Treg分化,比较WT小鼠与NLRP3^-/-小鼠Treg分化能力。结果NLRP3的缺失通过增加PPs和脾脏中Foxp3+Treg细胞的比例减轻DSS诱导的小鼠结肠炎。NLRP3^-/-结肠炎小鼠结肠中转录因子Foxp3和抗炎细胞因子IL-10的表达明显高于野生型结肠炎小鼠。进一步的体外研究表明,NLRP3缺失促进初始CD4+T细胞向Treg细胞分化。结论NLRP3缺失可以通过促进Treg细胞分化来减轻肠道炎症。

Objective To investigate the role of NLRP3 inflammasome in inflammatory bowel disease(IBD).Methods IBD model was established in wild-type(WT)mice and NLRP3 defective(NLRP3^-/-)mice by feeding dextran sodium sulfate(DSS).Then mice were divided into four groups:WT control group,WT IBD group,NLRP3^-/-control group and NLRP3^-/-IBD group.During DSS feeding,the weight of mice was recorded every day.After 7 days,the mice were sacrificed,and their serum,mesenteric lymph node(mLN),Payer’s Patches(PPs),spleen and colon were collected.HE and TUNEL staining were used to evaluate intestinal inflammatory damage and apoptosis.Flow cytometry was used to detect the proportions of T cells and B cells in each group.Serum proinflammatory cytokines levels were detected by ELISA.The expression of proinflammatory cytokine in colon of mice in each group was measured by Western blotting.The differentiation of naive CD4+T cells into Treg was induced in WT mice and NLRP3^-/-mice in vitro,and their differentiation ability was compared.Results The deficiency of NLRP3 alleviated DSS induced experimental mouse colitis by increasing the proportion of Foxp3+Treg cells in both Payer’s Patches and spleen.The expression levels of transcription factor Foxp3 and anti-inflammatory cytokine IL-10 in the colon from the colitis NLRP3^-/-mice were significantly higher than those from the WT mice.Further investigation indicated that the deletion of NLRP3 in naive CD4+T cells predominantly supported Treg differentiation in vitro.Conclusion The deficiency of NLRP3 could regulate intestinal inflammation through promoting Treg cell differentiation.