胆汁酸膜受体TGR5在小鼠骨髓来源的树突状细胞中的表达及其相关功能

目的 通过TGR5天然激动剂石胆酸(LCA)刺激小鼠树突状细胞(DC),探讨TGR5受体在DC成熟活化及吞噬功能方面的作用.方法 体外诱导小鼠骨髓细胞形成DC,LCA 30 μmol/L预处理2h后,用CFSE标记的胸腺凋亡细胞测试其吞噬功能；加入脂多糖(LPS)1 μg/mL诱导其成熟,6h后提取细胞总RNA,PCR法检测IL-12、TNF-α和IL-10等细胞因子；48 h后以流式细胞术检测细胞表面分子MHCII、CD80、CD86表达水平.组间比较采用t检验.结果 (1)LCA可以上调DC表达TGR5,并增强DC吞噬凋亡细胞功能(P＜0.05)；(2)LCA可以降低LPS引起的DC表面MHCⅡ、CD80和CD86表达水平(均P＜0.05),提示LCA可抑制DC成熟；(3)LCA可抑制LPS诱导的DC促炎性细胞因子IL-12、IL-6、TNF-α mRNA表达,而IL-10表达水平升高(均P＜0.05).结论 TGR5受体激动剂可抑制DC成熟并增强DC吞噬功能,发挥免疫调节作用.

Expression and function of the bile acid receptor TGR5 in dendritic cells from mouse bone marrow

Objective To investigate the effects of TGR5 receptor on maturation and phagocytosis of dendritic cells.Methods Dendritic cells(DCs) were induced from mouse bone marrow cells.For stimulation studies,DCs were pretreated with natural ligand of TGR5 lithocholic acid(LCA,30μol/L) for 2 hours.To assay for phagocytic activity, apoptotic thymocytes were labeled with CFSE,and then cultured with DCs;DCs were stimulated with LPS(1μg/mL) to induce maturation,total RNA were isolated in six hours,and RT-PCR was performed to measure IL-12,TNF-a and IL- 10 mRNA levels.After 48 hours,LPS stimulation,DC surface expression of MHC class II,CD80,CD86 were analyzed by flow cytometry.Results(1) LCA increased TGR5 expression in DCs,and enhanced the phagocytosis of apoptotic cells by DC(P<0.05);(2) LCA reduced the expression of MHC II,CD80 and CD86 on DC cell surface induced by LPS (P<0.05),suggesting that LCA could inhibit DC maturation.(3) LCA attenuated the increased expression of IL-12, IL-6.and TNF-a mRNA level induced by LPS treatment,while IL-10 expression level was up-regulated(P<0.05). Conclusion Activation of TGR5 could inhibit DC maturation and enhance DC phagocytosis in vitro,suggesting that TGR5 may play an important role in immune regulation.