Exendin-4 Inhibits Hepatic Lipogenesis by Increasing beta-Catenin Signaling
- Authors
- Seo, Mi Hae; Lee, Jinmi; Hong, Seok-Woo; Rhee, Eun-Jung; Park, Se Eun; Park, Cheol Young; Oh, Ki Won; Park, Sung Woo; Lee, Won-Young
- Issue Date
- 1-Dec-2016
- Publisher
- Public Library of Science
- Keywords
- Exendin-4 Hepatic Lipogenesis β-Catenin Signaling
- Citation
- PLoS ONE, v.11, no.12
- Journal Title
- PLoS ONE
- Volume
- 11
- Number
- 12
- URI
- https://scholarworks.bwise.kr/sch/handle/2021.sw.sch/8466
- DOI
- 10.1371/journal.pone.0166913
- ISSN
- 1932-6203
- Abstract
- The aim of this study is to investigate whether the beneficial effect of exendin-4 on hepatic steatosis is mediated by beta-catenin signaling. After the HepG2 human hepatoma cells were treated with PA for 24 hours, total triglycerides levels were increased in a dose-dependent manner, and the expression levels of perilipin family members were upregulated in cells treated with 400 mu M PA. For our in vitro model of hepatic steatosis, HepG2 cells were treated with 400 mu M palmitic acid (PA) in the presence or absence of 100 nM exendin-4 for 24 hours. PA increased the expression of lipogenic genes, such as sterol regulatory element- binding protein 1c (SREBP-1c), peroxisome proliferator-activated receptor gamma (PPAR.), stearoyl-CoA desaturase 1 (SCD1), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) and triglyceride synthesis-involved genes, such as diacylglycerol acyltransferase 1 (DGAT1) and diacylglycerol acyltransferase 2 (DGAT2) in HepG2 cells, whereas exendin-4 treatment significantly prevented the upregulation of SREBP-1c, PPAR gamma, SCD1, FAS, ACC, DGAT1 and DGAT2. Moreover, exendin-4 treatment increased the expression of phosphorylated glycogen synthase kinase-3 beta (GSK-3 beta) in the cytosolic fraction and the expression of beta-catenin and transcription factor 4 (TCF4) in the nuclear fraction. In addition, siRNA-mediated inhibition of beta-catenin upregulated the expression of lipogenic transcription factors. The protective effects of exendin-4 on intracellular triglyceride content and total triglyceride levels were not observed in cells treated with the beta-catenin inhibitor IWR-1. These data suggest that exendin-4 treatment improves hepatic steatosis by inhibiting lipogenesis via activation of Wnt/beta-catenin signaling.
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Collections - College of Medicine > Department of Internal Medicine > 1. Journal Articles
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