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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Physiol. | doi: 10.3389/fphys.2019.01077

Inhibited lipophagy suppresses lipid metabolism in zebrafish liver cells

Jing Wang1, Si-Lan Han1, Dong-Liang Lu1, Ling-Yu Li1,  Samwel M. Limbu1, 2,  Dongliang Li1,  Meiling Zhang1 and  Zhen-Yu Du1*
  • 1School of Life Sciences, East China Normal University, China
  • 2Department of Aquatic Sciences and Fisheries Technology, University of Dar es Salaam, Tanzania

Lipophagy degrades lipid droplets (LDs) through the lysosomal degradative pathway, thus plays important roles in regulating lipid metabolism in mammals. However, information on the existence and functions of lipophagy in fish lipid metabolism is still limited. In the present study, we confirmed the existence of lipophagy by observing the structures of LDs sequestered in autophagic vacuoles in the zebrafish liver cell line (ZFL) via electronic microscopy. Moreover, starved cells increased the mRNA expression of the microtubule-associated protein 1A/1B light chain 3 beta (LC3), which is a marker protein for autophagy and protein conversion from LC3-I to LC3-II. Inhibiting autophagy with chloroquine increased significantly the LDs content and decreased fatty acid β-oxidation and esterification activities in the ZFL cells cultured in the fed state. Furthermore, inhibiting autophagy function downregulated the mRNA expression of the genes and their proteins related to lipid metabolism. Altogether, the present study verified the existence of lipophagy and its essential regulatory roles in lipid metabolism in fish cells.

Keywords: Zebrafish liver cells, Lipophagy, Lipid Metabolism, Esterification, FATTY ACID β-OXIDATION

Received: 26 Apr 2018; Accepted: 06 Aug 2019.

Copyright: © 2019 Wang, Han, Lu, Li, Limbu, Li, Zhang and Du. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Zhen-Yu Du, East China Normal University, School of Life Sciences, Shanghai, 200241, China, zydu@bio.ecnu.edu.cn