系统性红斑狼疮患者外周血T细胞磷酸肌醇3激酶信号通路异常活化

Abnormal signaling activity of phosphatidyfinositol 3-kinase pathway in peripheral blood T cells from patients with systemic lupus erythematosus 2036

目的研究系统性红斑狼疮（SLE）患者外周血T细胞中磷酸肌醇3激酶（PI3K）信号通路活化情况及其临床意义。方法检测28例SLE患者的T细胞PI3K通路活性。8例类风湿关节炎患者为对照，另以15名健康者为正常对照组。外周血T细胞分离采用RosettSep T细胞提取试剂盒提取，PI3K活性采用免疫沉淀和ELISA法，Akt及其磷酸化蛋白运用免疫印迹法，T细胞增殖采用MTT法，细胞因子水平采用ELISA检测。结果新鲜分离的SLE患者外周血T细胞PI3K和Akt活性均显著高于正常对照组和类风湿关节炎组；SLE患者T细胞在体外培养24h后PI3K和Akt活性与正常对照组差异无统计学意义，而正常对照组T细胞用SLE患者血清孵育24h后PI3K和Akt活性显著增高；PI3K特异性抑制剂LY294002显著抑制SLE患者T细胞增殖（125±21vs197±26，P〈0．05）及分泌白细胞介素（IL）-6和IL-10[分别为（425±69）ng／Lvs（816±116）ng／L，P〈0．05；（114±18）ng／LV8（207±31）ng／L，P〈0．05]。新鲜分离的SLE患者外周血T细胞PI3K和Akt活性与SLEDM无相关关系。结论SLE患者T细胞存在PI3K信号通路异常活化，并与T细胞增殖和细胞因子分泌有关，SLE外周血中可能存在激活该通路的血清因子。

Objective To investigate the activity of phosphatidylinesitol 3-kinase （PDK） signal pathway, a cytoplasmic signaling pathway known to play an important role in T cell activation, in peripheral blood T cells from systemic lupus erythematosus （SLE） patients. Methods T cells were isolated from the peripheral blood samples of 28 SLE patients, 5 males and 23 females, with ResettSep T cell purification kit. PI3K activity was determined by immunoprecipitation and ELISA, and Western blotting was used to measure the Akt and phesphorylated Akt protein expression. T cell proliferation and cytokine production was examined by MTT test and ELISA respectively. Fifteen healthy adults and 8 active rheumatoid arthritis patients were used as controls. The T cells from the SLE patients and normal controls were treated with 10% normal control serum of SLE serum for 24 h （ ＂rest＂ ） and then to detect the PI3K and Akt activity. Some T cells from the SLE patients were stimulated with CD3/CD28 mono-antibodies or CD3/CD28 monoantibodies ＋ LY294002, a specific PI3K inhibitor, and then the proliferation and secretion of IL-6 and IL-10 were analyzed. Results Compared with the healthy controls and rheumatoid arthritis patients, the activity levels of PI3K and Akt in the T cells of peripheral blood from the SLE patients were significantly increased. T cells allowed to ＂rest＂ for 24 hours in culture medium showed a reversal of the changes in activity of PI3K and Akt. The activity of PI3K pathway was increased in the T cells from healthy controls when cultured with SLE serum. The proliferation and IL-6 and IL-10 secretion of the T cells from SLE patients cultured with LY294002 were inhibited. The PI3K and Akt activity levels of the T cells from SLE patients were not related to SLE disease activity index （SLEDM）. Conclusion The T cells from SLE patients show an abnormal activation of PI3K pathway which may be due, at least in part, to their exposure to relevant serum factors.