高迁移率族蛋白B1对小鼠调节性T细胞抑制性相关分子表达的影响

Influence of high mobility group box-1 protein on immunosuppression molecules expression of splenic regulatory T cells in mice

目的观察高迁移率族蛋白B1(HMGB1)对调节性T细胞(Treg)T淋巴细胞毒性相关抗原4(CTLA-4)及叉头翼状螺旋转录因子(Foxp3)表达的影响,并对其机制进行初步探讨。方法免疫磁珠法分离正常BALB/C小鼠脾脏CD4^+ CD25^+ Treg。采用固相包被抗CD3及可溶性CD28辅助活化,观察HMGB1刺激与CTLA-4及Foxp3表达的时间-效应关系及剂量-效应关系。结果HMGB1刺激Treg时,CTLA-4表达在24～72h均有所下调(P<0.05或P<0.01),其中以作用48、72h表达下调尤为明显(P<0.01);而不同剂量HMGB1(10、100、1000μ/L)刺激均可诱导CTLA-4表达下调(P<0.05或P<0.01),其中HMGB1浓度在1000μg/L时其表达下调最明显。Foxp3表达与CTLA-4呈现出相同的趋势。结论HMGB1能诱导Treg CTLA-4表达减弱。HMGB1可能通过下调Foxp3表达进而影响Treg免疫调节活性。

Objective To investigate the influence of high mobility group box-1 protein （HMGB1） on the expression of cytotoxic T lymphocyte-aasoeiated antigen 4 （CTLA-4） and intranuclear forkhead/winged helix transcription factor （Foxp3） of sphen regulatory T cells （Treg） and its potential regulating mechanism in mice. Methods CD4^＋ CD25^＋ Treg isolated from the spleeus of male BABL/c mice by magnetic beads were seeded on 96-well （ 1 × 10^5 cells/well） cell culture plates coated with anti- CD3 （1 rag/L） and soluble anti-CD28 （1 mg/L） ,and cells were stimulated with HMGB1 for various intervals or on different concentrations. After being stimulated, the expression of CTLA-4 and Foxp3 molecules in Treg was deteertemd. The time-and dose-dependent responses between HMGB1 and CTLA-4 as well as Foxp3 were analyzed by flow cytometry. Results After stimulation with HMGB1 ,the CTLA-4 expression levels on surface of splenic Treg in mice and intranuclear Foxp3 moleeules were markedly downregulated at 24 h to 72 h （P 〈 0.05 or P 〈 0.01 ） , and the expression levels of CTLA-4 and Foxp3 were lowest at 72 h （P 〈 0.01 ）. When Treg was cultured in the presence of 10μg/L, 100 μg/L, and 1000μg/ L HMGB1 for 72 h, respectively, the expression of CTLA-4 and Foxp3 was significantly down-regulated （P〈0.05 or P〈0.01） ,and values of beth molecules were lowest in 1000 μg/L HMGBl-treated group （P 〈 0.01 ）. Conclusion HMGB1 stimulation can significantly down-regulate the expression of CTLA-4 and Foxp3 mohcules of splenic Treg in mice. HMGB1 appears to be a potential immunoregulatory signal that influences the function of Treg by inhibiting CD4^＋ CD25^＋ Treg activity.