中文摘要：

目的：探讨高迁移率蛋白族B1（HMGB1）对T细胞的增殖抑制作用及其分子机制。方法：将培养的Jurkat细胞分为对照组、HMGB1（100ng／m1）12、24、48h组，HMGB1组加入HMGB1培养相应时间；将细胞分为对照组、HMGB110、100、1000ng／ml组，予不同浓度HMGB1培养24h；采用细胞计数试剂盒（CCK-8）法检测各组细胞增殖率，采用实时荧光定量-聚合酶链反应（RT-PCR）和Westernblot法检测各组细胞中p53mRNA、磷酸化p53及p53总蛋白的表达水平。将载有p53shRNA、p53mRNA表达序列及空白质料的病毒转染入Jurkat细胞中，并选择100ng／mlHMGB1刺激24h，采用同样方法检测细胞增殖率。最后，将细胞分为正常组、HMGBl组、SB203580[p38丝裂原活化蛋白激酶（p38MAPK）抑制剂]＋HMGB1组进行相应处理。收集各组细胞，RT—PCR和Westernblot法检测p53mRNA、磷酸化p53及p53总蛋白的表达水平。结果：HMGB1（100ng／m1）刺激细胞24、48h后细胞增殖率降低，较正常组差异有显著性（P〈0．05）；100、1000ng／mlHMGB1刺激细胞24h后，增殖率明显下降，与正常组相比差异具有统计学意义（P〈0．05）。HMGB1（100ng／m1）刺激细胞后，p53mRNA、磷酸化及总蛋白表达水平在24、48h逐步上升，且有明显统计学意义（P〈0．05）；HMGB1刺激24h，10、100ng／mlHMGB1刺激组细胞p53mRNA、p53磷酸化及总蛋白表达水平较正常组显著上升，但1000ng／mlHMGBl没有明显变化；在不同转染组中，予HMGB1刺激细胞，空载组增殖率降低，而p53shRNA表达组细胞增殖趋于正常，p53tuRNA过表达组增殖率较空载组下降更为明显。Jurkat细胞在p38MAPK阻断剂和HMGB1共同作用后，p53mRNA、磷酸化及总蛋白表达水平比HMGB1刺激组明显下降（P〈0．05）。结论：胞外HMGBI可通过诱导p38MAPK信号通路激活p53蛋白，抑制T细胞增殖。

英文摘要：

Objective：To investigate the inhibitory effect of high mobility group box-1 protein （HMGB1） on T cell proliferation and the regulation mechanisms thereof. Methods： Cultured Jurkat cells were divided into 4 groups： control group, HMGB1 treatment （100 ng/ml） for 12, 24 and 48 hours groups. Cells were also divided into control group, 10, 100 and 1 000 ng/ml HMGB1 treated groups, and then stimulated for 24 hours. Proliferation rates of cells were measured using cell counting kit （CCK-8）. The expression levels of p53 mRNA, phosphorylated p53 and p53 protein were determined by real-time polymerase chain reaction （RT-PCR） and Western blot respectively. Jurkat cells were transfected with lentivirus containing p53 shRNA, p53 mRNA sequence expressing plasmids or control vector. The cells were afterwards stimulated with HMGB1 （100 ng/ml）for 24 hours, and subjected to cell proliferation assay with the same methods mentioned above. In addition, Jurkat cells were divided into 3 groups： control group, HMGB1 group and HMGBl＋SB203580 group, and stimulated with indicated reagents for 24 hours. The expression levels of p53 mRNA; phosphorylated p53 and p53 protein were detected by RT-PCR and Western blot. Results： Compared to the control group, the proliferation rates of cells were decreased after HMGB 1 （100 ng/ml） stimulation for 24 and 48 hours （P〈0.05）. In dose-devendent stimulations, nroliferation rates were reduced in treatment with 100 or 1 000 ng/ml HMGB1 groups （P〈0.05）. The expression levels of p53 mRNA, phosphorylated p53 and p53 protein increased in cells after stimulation with 100 ng/ml HMGB 1 for 24 and 48 hours （P〈0.05）. The expression levels increased obviously in 10 and 100 ng/ml HMGB1 treated cells 24 hours later, but the level was not changed significantly in HMGB1 1 000 ng/ml group. After transfection, the proliferation rates of vector-expressing cells decreased obviously after HMGB1 stimulation. The proliferation of p53 shRNA-expressing cells was basically no