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Sci Rep. 2017 Nov 27;7(1):16362. doi: 10.1038/s41598-017-16587-9.

ATF4 overexpression induces early onset of hyperlipidaemia and hepatic steatosis and enhances adipogenesis in zebrafish.

Author information

1
Division of Hemato-Oncology, Department of Internal Medicine, Chang-Chung Memorial Hospital, 222 Maijin Road, Keelung, 204, Taiwan.
2
Department of Bioscience and Biotechnology, National Taiwan Ocean University, 2, Pei Ning Road, Keelung, 202, Taiwan.
3
Department of Radiology, Buddhist Tzu Chi General Hospital, Taichung Branch, No. 66 Fēngxìng Road Section 1, Taichung, 427, Taiwan.
4
School of Medicine, Tzu Chi University, No.701, Sec. 3, Jhongyang Road, Hualien, 97004, Taiwan.
5
Department of Bioscience and Biotechnology, National Taiwan Ocean University, 2, Pei Ning Road, Keelung, 202, Taiwan. gmher@mail.ntou.edu.tw.

Abstract

Activating transcription factor 4 (ATF4) is constitutively expressed in a variety of tissues, and regulates several pathological features associated with metabolic diseases such as non-alcoholic fatty liver diseases (NAFLD) and obesity. However, the role of ATF4 in animal model systems is poorly understood. To investigate ATF4 functions in zebrafish, we conditionally expressed ATF4 proteins, using a Tet-off transgenic system. We observed early-onset hyperlipidaemia and liver steatosis in ATF4 transgenic zebrafish (ATs) without doxycycline treatment (ATs - Dox). Oil Red O (ORO)-stained signals were predominant in the intravascular blood vessels and liver buds of larval ATs - Dox, indicating that ATF4 functionally promotes lipogenesis. Further, ATF4 overexpression accompanied the stimulation of the unfolded protein response. Therefore, adult ATs - Dox showed increased lipid accumulation, which led, in turn, to liver steatosis. Liver histology and ORO staining of ATs - Dox hepatocytes also indicated oxidative stress and induced NASH-like phenotypes. Moreover, ATF4 overexpression accelerated adipocyte differentiation via CCAAT enhancer binding protein-beta and peroxisome proliferator activated receptor-gamma inducible expression. ATs-Dox zebrafish showed increased weight gain with larger fat pads due to adipocyte hyperplasia. In this study, we report that ATF4 is a potential stimulator of lipid biosynthesis and adipogenesis in zebrafish.

PMID:
29180630
PMCID:
PMC5703967
DOI:
10.1038/s41598-017-16587-9
[Indexed for MEDLINE]
Free PMC Article

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