高迁移率族蛋白B1对大鼠脾脏树突状细胞细胞因子表达的影响

目的 观察高迁移率族蛋白B1(HMGB1)对树突状细胞(dendritic cells,DC)细胞因子蛋白合成和基因表达的影响.方法 分离正常Wistar大鼠脾脏DC后置于96孔培养板(1×105/孔),给予重组HMGB1刺激,研究HMGB1刺激与TNF-α,IL-12蛋白合成和基因表达的时间-效应关系,24孔细胞随机分为6组:正常对照24 h组(4孔/组)、正常对照48 h组(4孔/组)、正常对照72 h组(4孔/组)、HMGB1 24 h组(4孔/组)、HMGB1 48 h组(4孔/组)和HMGB1 72 h组(4孔/组),后3组分别以1 μg/mLHMGB1 刺激.刺激相应时间检测TNF-α,IL-12 mRNA的表达和蛋白水平.研究HMGB1刺激与TNF-α,IL-12蛋白合成和基因表达的剂量-效应关系,16孔细胞随机分为4组:正常对照组(4孔/组)、0.1μg/mL组(4孔/组)、1 μg/mL组(4孔/组)和10 μg/mL组(4孔/组),分别以相应剂量HMGB1刺激.刺激后48 h后检测TNF-α、IL-12 mRNA的表达和蛋白水平.应用Promega公司mRNA提取试剂盒裂解收集的DC,提取细胞mRNA.采用SYBR Green real-time(实时荧光定量)PCR技术检测TNF-α mRNA,IL-12mRNA表达水平.以三磷酸甘油脱氢酶(GAPDH)作为内参对照.扩增产物经Fast 7500 real-time PCR仪处理,作相对定量(RQ)分析.以ELISA试剂盒检测各组上清中IL-12,TNF-α蛋白水平.数据进行单因素方差分析,以P<0.05为差异具有统计学意义.结果 1 μg/mL HMGB1 刺激后,脾脏DC IL-12,TNF-α蛋白合成和基因表达均分别于24～72 h明显上调(P<0.05或P<0.01),其中以作用48 h后其表达上调尤为显著(P<0.01);0.1/.μg/mL,1 tcVmL,10μg/mL HMGB1刺激48 h均可诱导DC IL-12、TNF-α蛋白合成和基因表达增强(P<0.01),其中HMGB1浓度在1 μg/mL时,DC IL-12和TNF-α蛋白合成和基因表达表达最明显(P<0.01).结论 HMGB1诱导DC成熟分化过程中能促进DC合成、释放IL-12和TNF-α,从而发挥其免疫调节作用.

Effects of high mobility group box-1 protein on cytokine expreesion in splenic dendritic cells in rats

Objective To investigate the effect of high mobility group box-1 protein (HMGB1) on cytokine expression in splenic dendritic cell (DCs). Method DCs isolated from the spleens of male Wistar rats were seed-ed on 96-well (1×10s cells/well) cell culture plates, and the cells were stimulated with HMGB1 for various length of time or in different concentrations. (1) The time-dependent response between HMGB1 and tumor necrosis factor-α(TNF-α) as well as interleukin-12 (IL-12) gene/protein expressions: 24 wells of DCs were dividedly into six groups including 24 h-normal controls (n=4), 48 h-normal controls (n=4), 72 h-normal controls (n=4), and 24 h-HMGB1 treated group (n=4), 48 h-HMGB1 treated group (n=4) as well as 72 h-HMGB1 treated group (n=4), respectively. Among three HMGB1-treated groups, DCs were stiraulated by 1 μg/mL HMGB1. DCs were denatured in cell culture plates to determine gene expression of IL-12 as well as TNF-α, and supernatants were harvested to determine Il-12 as well as TNF-α protein levels. (2) The dose-dependent response between HMGB1 and TNF-α as well as IL-12 gene/protein expressions: 16 wells of DCs were dividedly into four groups in-cludingnormal controls (n=4), 0.1 μg/mL HMGB1 treated group (n=4), 1 μg/mL HMGB1 treated group (n =4), and 10 μg/mL HMGB1 treated group (n=4), respectively. After stimulated for 48 h, DCs were dena-tured in cell culture plates to determine gene expression of IL-12 as well as TNF-α, and supernatants were harvest-ed to determine IL-12 as well as TNF-α protein levels. Total RNA was extracted from cells using the single-step technique of acid guanidinium thiocyanate-chloroform extraction according to the manufacturer' s instruction (Promega, Madison, WI). mRNA for TNF-α and IL-12 were quantified by SYBR Green two-step, real-time re-verse transeription-polymerase chain reaction taking glyceraldehyde-3-phesphate dehydrogenase (GAPDH) as an internal standard. Levels of IL-12 and TNF-α in cell culture supernatants were determined with ELISA, strictly fol-lowing the protocols provided by the manufacturer. Data were analyzed with a one-way ANOVA. A P-values <0.05 were considered statistically significant. Results After stimulation with 1 μg/mL HMGB1, IL-12 and TNF-α protein and gene expressions in rat splenic DCs were markedly up-regulated at 24 h to 72 h (P<0.05 or P<0.01), and the expression levels of IL-12 and TNF-α peaked at 48 h (P<0.01). When DCs were cultured in the presence of 0.1 μg/mL, 1 μg/mL, and 10 μg/ml HMGBI for 48 h, expressions of IL-12 and TNF-α were also significantly up-regulated (P<0.01), and values of these cytokines were highest in 1 μg/mL HMGB1-treated group (P<0.01). Conclusions These data suggest that HMGB1 appears to be a potential immunostimulatory signal that induced DC maturation, and HMGB1 stimulation can result in marked up-regulation of IL-12 as well as TNF-α synthesis and release in splenic DCs.