白细胞介素-35对效应T细胞胞质内高迁移率族蛋白B1的影响及其机制

Effects of Interleukin 35 on intracellular distribution of high mobility group protein B1 in effector T cells and its molecular mechanism

目的观察白细胞介素-35(IL-35)对效应T细胞内高迁移率族蛋白B1(HMGB1)分布的影响,进一步探索其机制。方法分离、培养并活化雄性C57BL/6小鼠脾脏中CD4+T淋巴细胞,0.025%digitonin处理3 min后固定,FAC Scan流式细胞仪检测细胞质HMGB1的表达及IL-35的影响;进一步以1μmol/L EX527及1μmol/L SRT1720调节细胞内HMGB1的分布,观察细胞内LC3-Ⅱ和Beclin 1变化;最后应用蛋白质印迹法(Western blot)检测T细胞内信号转导及转录激活因子(STAT1)-鼠双微体基因2(MDM2)-p53信号转导通路的变化。符合正态性分布数据进行进行Student’s t检验,不符合正态分布数据进行独立样本非参数检验。结果活化效应性T细胞内,HMGB1含量[(58.02±12.77)%]高于对照组[(6.03±2.35)%,t=9.809,P<0.01],50 ng/ml重组IL-35处理组细胞质HMGB1[(28.50±10.66)%]低于anti-CD3/CD28组(t=4.418,P<0.01);SRT1720抑制细胞质LC3Ⅱ和Beclin 1的表达,与EX527作用相反;活化效应性T细胞中,IL-35促进STAT1磷酸化,抑制细胞质MDM2表达,进而降低p53降解,增加细胞核及细胞质p53。结论对STAT1-MDM2-p53信号转导通路的干预可能是IL-35影响高迁移率族蛋白B1分布进而干扰效应T细胞自噬的重要机制之一。

Objective To investigate the effects of interleukin(IL)-35 on intracellular distribution of high mobility group protein B1(HMGB1)in effector T cells,and its potential mechanism.Methods Effector T cells were isolated from spleens of male C57BL/6 mice and were cultured and activated in vitro.Upon treatment of 0.025%digitonin 3 mins,cytosolic HMGB1 was detected by FAC Scan flow cytometry analysis,as well as the impact of IL-35.Distribution of intracellular HMGB1 was modified with 1μmol/L EX527 or SRT1720,and expression LC3-Ⅱand Beclin 1 were furtherly monitored.Finally,signaling pathway of signal transducer and activators of transcription 1(STAT1)-murine double minute 2(MDM2)-p53 was tested by Western blotting.Datawas processed by SPSS software,version 25.0,and analyzed with Student′s t test or Nonparametric test.Results HMGB1 expression[(58.02±12.77)%]was higher than that of control group[(6.03±2.35)%],in activated effector T cells,t=9.809,P<0.01.Upon treatment of 50 ng/ml recombinant IL-35,expression of cytosolic HMGB1[(28.50±10.66)%]was lower than that of anti-CD3/CD28 group(t=4.418,P<0.01).SRT1720 inhibited the expression of LC3-Ⅱand Beclin 1,in contrary to EX527.IL-35 resulted phosphorylation of STAT1,inhibited cytosolic expression of MDM2 and consequently declined the degradation of p53.Both cytosolic and nuclear levels of p53 were elevated.Conclusion It could be hypothesized that IL-35 interfere distribution of intracellular HMGB1 through STAT1-MDM2-p53 signaling pathway,and furtherly impair autophagy in effector T cells,which is,at least partially,the intrinsic mechanism for its immunologic effects.