穿心莲内酯对HepG2细胞SREBP表达及脂质代谢的影响
Effects of Andrographolide on Expression of SREBPs and Lipid Metabolism in HepG2 Cells
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摘要: 目的 研究穿心莲内酯对人肝癌细胞株HepG2中固醇调节元件结合蛋白(SREBP)表达及脂质代谢的影响,并探讨其作用机制。方法 应用Cell Counting Kit-8(CCK-8)试剂盒检测细胞活力;双荧光素酶报告基因实验检测穿心莲内酯对SREBP转录活性的抑制作用;实时定量PCR(RT-qPCR)法检测SREBP及其靶基因mRNA的表达;甘油三酯、总胆固醇(TG、TC)测定试剂盒检测HepG2细胞中TG、TC的含量。结果 CCK-8法结果显示穿心莲内酯在0~80 μmol/L浓度范围内对HepG2细胞活力无明显影响;穿心莲内酯能够剂量依赖性的抑制HepG2细胞中SREBP的转录活性,同时浓度在20 μmol/L条件下能显著下调SREBP靶基因mRNA的表达水平;此外,经穿心莲内酯体外干预后,HepG2细胞内TG、TC的含量明显减少。结论 穿心莲内酯可能通过抑制SREBP的转录活性及其靶基因mRNA的表达,进而减少细胞内TG、TC的含量,起到改善肝细胞的脂质代谢作用。Abstract: OBJECTIVE To explore the effects of Andrographolide on expression of SREBPs and lipid metabolism in HepG2 cells, and to study the possible mechanism. METHODS Cell viability was evaluated by Cell Counting Kit-8; Dual luciferase reporter gene assay was used to test the transcription activity of SREBP; The SREBPs target genes expressions were measured by Quantitative Real-Time PCR; The intracellular triglyceride (TG) and total cholestero l(TC) contents were measured by using commercially available test kits. RESULTS Andrographolide in 0~80 μmol/L concentration range has no effect on HepG2 cell activity; Andrographolide could markly inhibited human SRE promoter activity in a dose-dependent manner, and the mRNA level of SREBPs target genes were significantly downregulated by Andrographolide at the dose of 35 μmol/L. In addition, contents of intracellular cholesterol and triglyceride were significantly suppressed by Andrographolide treatment. CONCLUSION These results suggested that Andrographolide might improve lipid metabolism through downregulating the mRNA levels of SREBPs target genes.