IL-6上调SCD1表达对HepG2细胞脂质合成功能的影响*

目的 探讨IL-6对HepG2细胞硬脂酰辅酶A去饱和酶1 （SCD1）基因的影响及其SCD1基因表达的改变对细胞脂质合成的影响。方法 应用rIL-6刺激HepG2细胞,检测细胞内脂质合成以及细胞SCD1基因水平变化。分别构建人SCD1真核表达质粒和小干扰（small interfering） RNA,转染HepG2细胞,观察改变SCD1水平后HepG2细胞脂代谢相关基因表达的变化以及细胞内脂质合成的变化。结果 rIL-6刺激HepG2细胞甘油三酯水平显著高于对照组（P<0.05）;与空质粒组比,转染真核表达质粒细胞SCD1 蛋白表达增加,细胞脂质合成相关基因SREBP1c和FASN相对水平增加1.35倍和1.27倍,脂质氧化代谢相关基因PPARα和ASCL3水平降低12.3%和13.5%;细胞甘油三酯水平显著升高（P<0.01）,而转染small interfering RNA,再用rIL-6刺激HepG2细胞SCD1蛋白表达显著降低,细胞甘油三酯水平也显著降低（P<0.05）,脂质合成相关基因SREBP1c和FASN水平显著下降了32.3%和51.9%,脂质分解相关基因PPARα相对水平也下降了80%（P<0.05）,而ASCL3水平无显著变化（P=0.832）。结论 rIL-6通过上调HepG2细胞SCD1基因表达,引起细胞内脂质合成增加,导致甘油三酯含量增多。

Upregulation of SCD1 gene-related lipid synthesis by IL-6 stimulus in HepG2 cells in vitro

Objective To investigate the upregulation of stearoyl-CoA desaturase 1（SCD1）-related lipid synthesis by IL-6 stimulus in HepG2 cells in vitro. Methods HepG2 cells were stimulated by rIL-6,and the lipid accumulation and SCD1 levels were evaluated. The SCD1 eukaryotic plasmid and small interfering RNA were conducted and transfected into HepG2 cells,respectively,and the lipid metabolism-related genes and intracellular triglyceride contents were detected. Results The intracellular triglyceride content in rIL-6-stimulated cells was significantly higher than in control group（P<0.05）;the SCD1 gene increased by 1.36 folds compared with in the control （P<0.01） and the SCD1 protein increased at the same time;the upregulation of intracellular lipid synthesis-related SREBP1c and FASN also increased by 1.35 and 1.27 folds,respectively,and the downregulation of lipid oxidation-related PPARα and ASCL3 decreased by 12.3% and 13.5%,respectively;In addition,the SCD1 transfection increased intracellular TG content in HepG2 cells（P<0.01） as compared to that in vector transfected group;conversely,after transfection with small interfering RNA and stimulation by rIL-6,the SCD1 was reduced compared with in the negative control, the intracellular TG content significantly decreased（P<0.05） and the lipid synthesis-related SREBP1c and FASN decreased by 32.3% and 51.9%, while the lipid oxidation-related PPARα also decreased by 80% （P<0.05） with the ASCL3 gene not significantly changed （P=0.832）. Conclusion rIL-6 stimulation might induce lipid synthesis and increase the triglyceride content by upregulating SCD1 expression in HepG2 cells.