棕榈酸通过激活 C/EBPβ 介导的 G0S2 表达诱导 HepG2 细胞脂肪积累。

Palmitate induces fat accumulation by activating C/EBPβ-mediated G0S2 expression in HepG2 cells.

机构信息

Department of Gerontology, the Second Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China.

Department of Infectious Diseases, the First People's Hospital of Jinzhong, Jinzhong 030600, Shanxi Province, China.

出版信息

World J Gastroenterol. 2017 Nov 21;23(43):7705-7715. doi: 10.3748/wjg.v23.i43.7705.

AIM

To determine the role of G0/G1 switch gene 2 (G0S2) and its transcriptional regulation in palmitate-induced hepatic lipid accumulation.

METHODS

HepG2 cells were treated with palmitate, or palmitate in combination with CCAAT/enhancer binding protein (C/EBP)β siRNA or G0S2 siRNA. The mRNA expression of C/EBPβ, peroxisome proliferator-activated receptor (PPAR)γ and PPARγ target genes (, , and ) was examined by qPCR. The protein expression of C/EBPβ, PPARγ, and G0S2 was determined by Western blotting. Lipid accumulation was detected with Oil Red O staining and quantified by absorbance value of the extracted Oil Red O dye. Lipolysis was evaluated by measuring the amount of glycerol released into the medium.

RESULTS

Palmitate caused a dose-dependent increase in lipid accumulation and a dose-dependent decrease in lipolysis in HepG2 cells. In addition, palmitate increased the mRNA expression of C/EBPβ, PPARγ, and PPARγ target genes (, , , and ) and the protein expression of C/EBPβ, PPARγ, and G0S2 in a dose-dependent manner. Knockdown of C/EBPβ decreased palmitate-induced PPARγ and its target genes (, , , and ) mRNA expression and palmitate-induced PPARγ and G0S2 protein expression in HepG2 cells. Knockdown of C/EBPβ also attenuated lipid accumulation and augmented lipolysis in palmitate-treated HepG2 cells. G0S2 knockdown attenuated lipid accumulation and augmented lipolysis, while G0S2 knockdown had no effects on the mRNA expression of C/EBPβ, PPARγ, and PPARγ target genes (, and ) in palmitate-treated HepG2 cells.

CONCLUSION

Palmitate can induce lipid accumulation in HepG2 cells by activating C/EBPβ-mediated G0S2 expression.

目的

探讨 G0/G1 开关基因 2（G0S2）及其转录调控在软脂酸诱导的肝脂质积累中的作用。

方法

用软脂酸或软脂酸联合 CCAAT/增强子结合蛋白（C/EBP）βsiRNA 或 G0S2siRNA 处理 HepG2 细胞。用 qPCR 检测 C/EBPβ、过氧化物酶体增殖物激活受体（PPAR）γ及其靶基因（、、和）的 mRNA 表达。用 Western blot 检测 C/EBPβ、PPARγ和 G0S2 的蛋白表达。用油红 O 染色检测脂滴积累，并通过提取的油红 O 染料的吸光度值进行定量。通过测量释放到培养基中的甘油量来评估脂解作用。

结果

软脂酸呈剂量依赖性增加 HepG2 细胞的脂质积累，呈剂量依赖性降低脂解作用。此外，软脂酸呈剂量依赖性增加 C/EBPβ、PPARγ及其靶基因（、、、和）的 mRNA 表达和 C/EBPβ、PPARγ和 G0S2 的蛋白表达。C/EBPβ 敲低降低了软脂酸诱导的 PPARγ及其靶基因（、、、和）的 mRNA 表达和软脂酸诱导的 PPARγ和 G0S2 蛋白表达。C/EBPβ 敲低还减弱了软脂酸处理的 HepG2 细胞中的脂质积累并增强了脂解作用。G0S2 敲低减弱了脂质积累并增强了脂解作用，而 G0S2 敲低对软脂酸处理的 HepG2 细胞中 C/EBPβ、PPARγ和 PPARγ靶基因（、和）的 mRNA 表达没有影响。