NF-κB途径介导硫酸吲哚酚抑制THP-1源性巨噬泡沫细胞SR-B1的表达

Indoxyl sulfate inhibits SR-B1 expression in THP-1 derived macrophage foam cells through NF-κB pathway

目的观察尿毒症毒素硫酸吲哚酚(IS)是否促进巨噬泡沫细胞脂滴的蓄积,以及对细胞内B类1型清道夫受体(SR-B1)表达和核因子NF-κB活化的影响。方法体外佛波酯(PMA)诱导人源单核细胞系THP-1分化为巨噬细胞,加入氧化低密度脂蛋白(ox-LDL)培养促进巨噬细胞泡沫化,随后以不同浓度的IS干预巨噬泡沫细胞,油红O染色观察细胞内脂滴变化,实时PCR和Western blotting检测SR-B1 m RNA和蛋白表达的水平,ELISA法检测NF-κB活化情况;经NF-κB抑制剂四氢化吡咯二硫代氨基甲酸酯(PDTC)预处理后IS再干预,实时PCR检测巨噬泡沫细胞内SR-B1 m RNA表达的变化。结果与对照组(IS 0μmol/L)比较,IS干预后巨噬泡沫细胞内脂滴明显增加,随着IS浓度的升高,细胞内脂滴逐渐增加;IS干预后巨噬泡沫细胞的NF-κB活化程度增高,差异有统计学意义(P<0.05)。与对照组比较,细胞在不同浓度的IS(2.5、25、250μmol/L)处理下,SR-B1 m RNA和蛋白的表达下降,随着IS浓度的增加,SR-B1和蛋白逐渐减少,呈现浓度依赖性,差异有统计学意义(P<0.05)。PDTC预处理后SR-B1m RNA表达增加,差异有统计学意义(P<0.05)。结论 IS抑制SR-B1 m RNA和蛋白的表达,增加THP-1源性巨噬泡沫细胞胆固醇的蓄积,促进巨噬细胞泡沫化,从而促进动脉粥样硬化。NF-κB活化可能是IS抑制SR-B1 m RNA表达的可能机制之一。

Objective To investigate the regulatory effects of indoxyl sulfate（IS） on lipid droplets accumulation and Scavenger Receptor Class B Type 1（SR-B1） expression as well as the activation of nuclear factor-kappa B（NF-κB） in macrophage foam cells. Methods THP-1 monocytes were induced to differentiate to macrophages by using phorbol myristate acetate（PMA）. Afterwards, the macrophages were treated with ox-LDL to form macrophage foam cells and then were treated with different concentrations of indoxyl sulfate（IS）. The changes in intracellular lipid droplets were observed by using oil red O staining.Real-time PCR and Western blotting were used to detect the expression of SR-B1 m RNA and protein.Sandwich ELISA was used to measure the NF-κB activation in foam cells. The change of SR-B1 level in the foam cells were examined by RT-PCR after pretreated with NF-κB inhibitor PDTC. Results Compared with the control group（IS 0 μmol / L）,IS increased the accumulation of lipid droplets, promoted NF-κB activation, and down-regulated the expression of SR-B1 m RNA and protein, which were in dose-dependent manner（P〈0.05）. After treated with PDTC, the IS-induced inhibition of SR-B1 expression was reversed（P〈0.05）. Conclusions Indoxyl sulfate promotes atherosclerosis by down-regulating the expression of SR-B1. NF-κB activation may be one of the signaling pathways by which IS inhibits the SR-B1 m RNA expression.