HMGB1/TLR4介导狼疮性肾炎肾小球细胞增殖和细胞外基质沉积

目的探究高迁移率族蛋白1(high mobility group protein B1,HMGB1)和其受体Toll样受体4(Toll like receptor 4,TLR4)介导狼疮性肾炎(lupus nephritis,LN)肾小球细胞增殖和细胞外基质沉积机制。方法采用免疫组化、免疫细胞化学技术检测LN患者肾穿标本和MRL/lpr小鼠肾小球细胞中TLR4表达水平;重组HMGB1刺激人肾小球系膜细胞(human mesangial cell,HMC),运用Western blot技术检测TLR4和髓样分化因子88(myeloid differentiation factor 88,Myd88)表达水平;LN患者置换血浆刺激HMC,采用CCK8试剂盒检测细胞增殖水平,Western blot技术检测纤连蛋白(fibronectin,FN)表达水平,ELISA技术检测HMC培养上清中FN水平。结果与对照组相比,LN患者及小鼠肾小球细胞中TLR4水平均上调;与对照组相比,重组HMGB1刺激HMC后,TLR4和Myd88水平上调;而抑制HMGB1及TLR4均可改善LN患者置换血浆介导的HMC增殖水平升高及FN合成和分泌增加(均P<0.05)。结论HMGB1可能通过激活其受体TLR4介导LN系膜细胞的增殖活性增强及细胞外基质沉积增加。

HMGB1/TLR4 mediates proliferation and extracellular matrix deposition of glomerular mesangial cells in LN

Aim To investigate the mechanism of the mediation of high mobility group protein B1(HMGB1)and Toll like receptor 4(TLR4)in the proliferation and extracellular matrix deposition of glomerular mesangial cells in lupus nephritis.Methods Immunohistochemistry and immunocytochemistry were employed to detect the TLR4 expression levels in the LN clinical specimens and MRL/lpr mice.Western blot was used to detect the TLR4 and Myd88 expression levels in human mesangial cells stimulated by recombinant HMGB1.Cell counting kit-8,Western blot and ELISA were employed to detect the proliferation and FN expression levels in HMCs stimulated by the exchange plasma of LN patients.Results Immunohistochemistry and immunocytochemistry results showed that compared with control groups,the expression levels of TLR4 in glomeruli cells of LN patients and MRL/lpr mice were up-regulated.Western blot showed that compared with control groups,the expression levels of TLR4 and Myd88 increased in HMCs stimulated by recombinant HMGB1.While the inhibition of HMGB1 and TLR4 both improved the proliferation,FN synthesis and FN secretion of HMCs induced by the exchange plasma of LN patients(both P<0.05).Conclusion HMGB1 may participate in the pathogenesis of LN by activating TLR4 to mediate the proliferation and extracellular matrix deposition of mesangial cells.