内质网应激协同促进脂多糖诱导的巨噬细胞炎症反应

摘要

Objective To investigate the protective mechanism of endoplasmic reticulum stress (ERS) inhibition against inflammation-induced acute liver injury using a mouse model.Methods Marrow-derived stem cells were isolated from mouse femur and used to derive macrophages for analysis in experimental inflammation conditions,established by exposure to LPS and consequent activation of TLR4.Tunicamycin,an ERS chemical inducer,was applied to interfere the inflammation model condition.Affect on the inflammation-related factor MAPK was detected by western blot,and affects on gene expression of inflammatory factors were measured by real-time quantitative PCR.Affect on TNFα was also measured by ELISA.Results Expression of TNFα,IL-6 and IL-1β was induced upon exposure to LPS,with the peak levels being reached at 4 hours of exposure (TNFα,0.82±0.24;IL-1 β,2.20±0.69;IL-6,0.330±0.150).Tunicamycin significantly enhanced the LPS-induced up-regulation of TNFα,IL-6 and IL-1β expression (TNFα,1.44±0.38,t =2.8,P ＜ 0.05;IL-1β,16.063.40,t =7.93,P ＜ 0.05;IL-6,31.1610.60,t =5.08,P ＜ 0.05).The tuniamycin treatment also enhanced the LPS-induced up-regulation of the protein expression of phospo-p38,phospho-JNK and phoshpo-ERK.Conclusion ERS collaborates with LPS to promote the TLR4-mediated inflammatory response of macrophages,and this collaboration may be a pathogenic mechanism underlying progressive development of acute liver injury.%目的 研究内质网应激对脂多糖诱导巨噬细胞引发炎症反应的影响,探讨抑制内质网应激改善急性肝衰竭肝损伤的保护机制. 方法 通过小鼠的股骨分离骨髓干细胞,经过分化培养获得骨髓来源的巨噬细胞,再通过脂多糖诱导炎症反应细胞模型.试验分为正常巨噬细胞组、脂多糖处理巨噬细胞组和衣霉素与脂多糖联合处理巨噬细胞组.通过实时定量PCR法检测巨噬细胞炎症细胞因子肿瘤坏死因子(TNF)α、白细胞介素(IL)-6和IL-1 β的基因表达水平;用酶联免疫吸附法检测巨噬细胞培养上清液中TNF α的蛋白表达水平;通过Western blot检测巨噬细胞中炎症相关信号通路细胞外信号调节蛋白激酶(ERK)、c-Jun N末端蛋白激酶(JNK)和p38丝裂原活化蛋白激酶(p-p38 MAPK)磷酸化水平的表达情况.多组之间均数的比较采用方差分析. 结果 脂多糖作用于巨噬细胞后,炎症因子TNFα、IL-1 β和IL-6的相对基因表达水平明显升高,在4h时达到最高水平,分别为0.82±0.24、2.20±0.69、0.330±0.150;在用衣霉素干预炎症细胞后,则进一步上调TNFα、IL-6和IL-1 β的表达水平(TNF α:1.44±0.38,F=9.11,P＜0.05;IL-1 β:16.00±3.40,F=12.29,P＜0.05;IL-6:31.10±10.60,F=21.37,P＜ 0.05). Western blot结果显示,衣霉素干预后进一步促进了脂多糖诱导的p-p38 MAPK、p-JNK和p-ERK的蛋白表达.结论 内质网应激显著增强脂多糖刺激巨噬细胞诱导的炎症反应,因此内质网应激协同脂多糖诱导的炎症反应可能是内质网应激促进急性肝衰竭肝损伤发生和发展的致病机制之一.