艾塞那肽通过激活AMPK抑制脂肪酸诱导肝细胞脂肪沉积及炎症反应

Exenatide inhibits fatty acid induced hepatocyte steatosis and inflammation through activating AMPK

目的:探讨胰高血糖素样肽-1(glucagonlike peptide-1,GLP-1)受体激动剂艾塞那肽(exenatide,EXE)对肝细胞脂肪沉积作用及机制.方法:采用棕榈酸(palmitic acid,PA)诱导HepG2细胞沉积模型,将不同剂量的EXE(25-100 nmoL/L)与PA(500μmoL/L)共同孵育24 h.采用油红O染色及细胞内甘油三酯(triglyceride,TG)含量检测观察脂肪沉积程度;实时定量PCR检测(real-time quantitative PCR,qRT-PCR)脂肪酸合酶(fatty acid synthase,FAS)以及肿瘤坏死因子-α(tumor necrosis factorα,TNF-α)、白介素-6(interleukin-6,IL-6)的表达;Western blot检测p-腺苷酸激活的蛋白激酶(AMP-activated protein kinase,AMPK)及AMPK表达.我们还采用AMPK抑制剂对调控AMPK在EXE抑制脂肪沉积及炎症反应中的作用进一步的验证.结果:PA显著升高HepG2细胞中的TG及油红O含量,增加FAS的表达,与对照组比较有统计学差异(均P<0.05).EXE能剂量依赖性抑制PA诱导的TG及油红O含量升高及FAS基因激活,与PA组比较有统计学差异(均P<0.05).PA处理组TNF-α、IL-6的表达较对照组显著升高,与对照组比较有统计学差异(均P<0.05).EXE能剂量依赖性抑制PA诱导TNF-α、IL-6的表达升高,与PA组比较有统计学差异(均P<0.05).AMPK抑制剂能显著降低EXE对AMPK的激活作用,还显著降低了EXE对PA诱导脂肪沉积及FAS激动的抑制作用,与EXE单独作用组比较有统计学差异(均P<0.05).此外,AMPK抑制剂能显著降低EXE对PA诱导TNF-α、IL-6激活的抑制作用,与EXE单独作用组比较差异有统计学意义(均P<0.05).结论:EXE可能通过激活AMPK减少脂肪酸诱导肝细胞脂肪沉积及炎症反应.

AIM： To detect the effect of glucagon-like peptide-1（GLP-1） agonist exenatide（EXE）on fat deposition in liver cells and explore the underlying mechanism.METHODS： A HepG2 cell deposition model was induced with palmitic acid（PA）. After cells were incubated with different doses of EXE（25-100nmoL/L） and PA（500 μmoL/L） for 24 h, fatty deposition was assessed by oil red O staining and the level of intracellular triglyceride（TG）.Real-time quantitative PCR（qRT-PCR） was used to detect the expression of lipid metabolism related genes, including fatty acid synthase（FAS）,tumor necrosis factor α（TNF-α）, and interleukin6（IL-6）. The expression of p-AMPK and AMPK protein was tested by Western blot. An AMPK inhibitor was used to explore the role of AMPK in fat deposition and inflammation.RESULTS： Compared with the control group,PA significantly elevated TG and oil red O content, as well as the expression of FAS in HepG2 cells（P 〈0.05）. EXE significantly inhibited PA induced elevation of TG and oil red O content, as well as FAS gene expression in adose dependent manner（P 〈0.05）. The expression of TNF-α and IL-6 significantly increased in the PA treated group（P 〈0.05）. EXE significantly inhibited the expression of TNF-α and IL-6 in PA treated HepG2 cells（P 〈0.05）. Co-treatment with AMPK inhibitor significantly reduced the effect of EXE on AMPK, and reduced the inhibitory effect of EXE on fatty deposition and PA induced FAS activation（P 〈0.05）. AMPK inhibitor significantly diminished the inhibitory effect of EXE on TNF-α and IL-6 activation induced by PA（P〈 0.05）.CONCLUSION： EXE reduces fatty acid induced fatty deposition and inflammatory response in liver cells through activation of AMPK.