雷公藤抑制致敏小鼠CD4^+T细胞核因子GATA_3、NFAT的活性

Inhibition of the DNA-binding activity of GATA_3 and NFAT in CD4~ +T lymphocytes in sensitized mice by triptolide

目的探讨致敏小鼠CD4`^+ T淋巴细胞核转录因子GATA_3、NFAT活性的变化及雷公藤内酯醇(TP)的作用。方法采用卵蛋白(OVA)致敏的方法建立模型;运用panni ng法分离CD4^+T淋巴细胞;通过凝胶电泳迁移率实验(EMSA)对CD4^+T 淋巴细胞核因子GATA_3、NFAT的DNA结合活性及TP的作用进行检测,同时就TP的作用与地 塞米松(DM)相比较。结果正常小鼠CD4^+T 淋巴细胞核因子GATA_3、NFAT的活性很弱,致敏小鼠CD4^+T淋巴细胞体外经伴刀 豆蛋白A(ConA)刺激后,GATA_3、NFAT的活性与正常对照组比较显著增强,并呈时间依 赖关系。经TP、DM处理后,GATA_3、NFAT的活性显著减弱。结论 GATA_3和NFAT是调控Th2类细胞因子基因转录的重要核因子。TP、DM抑制Th 2类细胞因子基因转录的分子机制可能与其抑制GATA_3、NFAT的DNA结合活性有关。

Objective To explore the changes of nuclear factors GATA_3,NFAT activities in CD4^+ T lymphocytes in sensitized mice,and the effects of triptolide(TP ).MethodsThe peritoneal injection of ovalbumin(OVA)was used to produce the sensitized BALB/c mouse model Panning method was used to isolate CD4^+T lymphocytes.The DNA- binding activity of GATA3 and NFAT in CD4^+T lymphocytes by treatment with TP and dexamethasone(DM)were assayed by using electro phoretic mobility shift assay(EMSA).ResultsThere were faint activities of GATA_3 and NFAT activities i n CD4^+T lymphocytes in normal controls.After stimulation with ConA,DNA-binding activities of GATA_3 and NFAT in CD4^+ T lymphocytes of sensitized mice were higher than that in the normal controls.Changes of DNA-binding activities were in a time-dependent manner.TP and DM could inhibit the DNA-binding activities of GATA_3 and NFAT.ConclusionsGATA_3 and NFAT are important nuclear transcription facto rs that regulate transcription of Th_2 type cytokines.Molecular mec hanisms for the suppressed expression of Th_2 type cytokines by TP or DM may be involved in the inhibition of GATA_3 and NFAT.