TLR4介导高迁移率族蛋白致系统性红斑狼疮肾损害的作用研究

目的 探讨高迁移率族蛋白1(HMGB1)致红斑性狼疮肾损害的作用机制与Toll样受体4(Toll-like receptor 4,TLR4)表达的相关性.方法 ELISA检测12例健康对照组、16例系统性红斑狼疮(systemic lupus eqrthematosus,SLE)无肾脏损害和18例狼疮性肾炎(lupus nephritis,LN)患者血清中HMGB1、基质金属蛋白酶-2(MMP-2)和基质金属蛋白酶组织抑制剂-2(TIMP-2)的表达情况;流式细胞术检测外周血CD3/TLR4和CD14/TLR4表达情况;分离外周血单个核细胞(PBMC),RT-PCR检测HMGB1 mRNA的表达变化.结果 HMGB1 mRNA相对表达量及血清中HMGB1蛋白在LN组明显高于SLE组和健康对照组;流式细胞术显示CD14+的单核细胞表面HMGB1受体TLR4在LN组表达最高(P＜0.05),且与尿蛋白呈正相关(P＜0.01);LN患者血清中MMP-2和TIMP-2蛋白的浓度明显低于SLE和健康对照组,同时MMP-2/TIMP-2比值下降.HMGB1 mRNA及CD14+/TLR4+与MMP-2/TIMP-2比值均呈显著负相关;LN组患者血清中HMGB1蛋白水平与蛋白尿呈正相关,与MMP-2/TIMP-2比值呈显著负相关.结论 HMGB1是狼疮性肾炎发病中的重要细胞因子;HMGB1可能部分通过TLR4激活PBMC,降低MMP-2/TIMP-2的活性,从而引起蛋白尿.

The effect of HMGB1 on the renal injure of systemic lupus erythematosus mediated in part via the TLR4 pathway

Objective To investigate the relationship between the effect of high mobility group protein box 1 (HMGBI) on the renal injure of systemic lupus erythematosus (SLE) and the expression of Toll-like receptor 4(TLR4). Methods The level of HMGB1, MMP-2 and TIMP-2 in serum from 16 pa-tients with SLE, 18 patients with lupus nephritis(LN) and 12 healthy people were measured by ELISA. The fresh peripheral blood mononuelear cell (PBMC) were isolated and the total RNA was extracted. Then the mRNA expression of HMGB1 was amplified by RT-PCR. Flow cytometry analysis was performed to study cell surface markers and the expression of TLR4. Results RT-PCR and ELISA results showed that the expres-sions of mRNA and level of HMGB1 protein in serum were higher in patients with LN than those in SLE and healthy people. The expression of TLR4 in CD14+ monecytes of patients with LN was higher than that with SLE and healthy people, while there were no significance in CD3+ T cells among LN, SLE and healthy peo-ple. The expressions of MMP-2 and TIMP-2 in serum of LN was lower than that in SLE and healthy people, at the same time the ratio of MMP-2/TIMP-2 decreased in LN group. HMGB1 mRNA and CD14+/TLR4+ was negatively correlated with the ratio of MMP-2/TIMP-2, and the level of HMGB1 in serum was positively correlated with proteinuria, while negatively correlated with the ratio of MMP-2/TIMP-2 in LN. Conclusion HMGB1 is one of the important cytokine in the pathogenesis of lupus nephritis. HMGBI might play a role in proteinuria of lupus nephritis in part via TLR4 pathway to activate monocytes and decrease the expression of MMP-2/TIMP-2.