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Xu H, Dong X, Ai Q, Mai K, Xu W, Zhang Y, Zuo R. Regulation of tissue LC-PUFA contents, Δ6 fatty acyl desaturase (FADS2) gene expression and the methylation of the putative FADS2 gene promoter by different dietary fatty acid profiles in Japanese seabass (Lateolabrax japonicus). PLoS One 2014; 9:e87726. [PMID: 24498178 PMCID: PMC3909213 DOI: 10.1371/journal.pone.0087726] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 01/01/2014] [Indexed: 12/01/2022] Open
Abstract
The present study was conducted to evaluate the influences of different dietary fatty acid profiles on the tissue content and biosynthesis of LC-PUFA in a euryhaline species Japanese seabass reared in seawater. Six diets were prepared, each with a characteristic fatty acid: Diet PA: Palmitic acid (C16:0); Diet SA: Stearic acid (C18:0); Diet OA: Oleic acid (C18:1n-9); Diet LNA: α-linolenic acid (C18:3n-3); Diet N-3 LC-PUFA: n-3 LC-PUFA (DHA+EPA); Diet FO: the fish oil control. A 10-week feeding trial was conducted using juvenile fish (29.53 ± 0.86 g). The results showed that Japanese seabass had limited capacity to synthesize LC-PUFA and fish fed PA, SA, OA and LNA showed significantly lower tissue n-3 LC-PUFA contents compared to fish fed N-3 LC-PUFA and FO. The putative gene promoter and full-length cDNA of FADS2 was cloned and characterized. The protein sequence was confirmed to be homologous to FADS2s of marine teleosts and possessed all the characteristic features of microsomal fatty acid desaturases. The FADS2 transcript levels in liver of fish fed N-3 LC-PUFA and FO were significantly lower than those in fish fed other diets except LNA while Diet PA significantly up-regulated the FADS2 gene expression compared to Diet LNA, N-3 LC-PUFA and FO. Inversely, fish fed N-3 LC-PUFA and FO showed significantly higher promoter methylation rates of FADS2 gene compared to fish fed the LC-PUFA deficient diets. These results suggested that Japanese seabass had low LC-PUFA synthesis capacity and LC-PUFA deficient diets caused significantly reduced tissue n-3 LC-PUFA contents. The liver gene expression of FADS2 was up-regulated in groups enriched in C16:0, C18:0 and C18:1n-9 respectively but not in the group enriched in C18:3n-3 compared to groups with high n-3 LC-PUFA contents. The FADS2 gene expression regulated by dietary fatty acids was significantly negatively correlated with the methylation rate of putative FADS2 gene promoter.
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Affiliation(s)
- Houguo Xu
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) & Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
- Key Laboratory of Chinese Ministry of Agriculture for Sustainable Utilization of Marine Fisheries Resources, Yellow Sea Fisheries Research Institute, Qingdao, China
| | - Xiaojing Dong
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) & Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Qinghui Ai
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) & Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Kangsen Mai
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) & Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Wei Xu
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) & Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Yanjiao Zhang
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) & Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
| | - Rantao Zuo
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) & Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China
- Key Laboratory of Mariculture and Stock Enhancement in North China's Sea (Ministry of Agriculture), Dalian Ocean University, Dalian, China
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Ai ZL, Zhu CH, Min M, Wang J, Lan CH, Fan LL, Sun WJ, Chen DF. The Role of Hepatic Liver X Receptor α-and Sterol Regulatory Element Binding Protein-1c-Mediated Lipid Disorder in the Pathogenesis of Non-Alcoholic Steatohepatitis in Rats. J Int Med Res 2011; 39:1219-29. [PMID: 21986124 DOI: 10.1177/147323001103900410] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Liver X receptor α (LXRα) and sterol regulatory element binding protein-1c (SREBP-1c) were studied in rats with non-alcoholic steatohepatitis (NASH) induced by a high-fat diet. Forty 5-week-old rats were fed either a high-fat diet ( n = 30) or a normal diet ( n = 10) for 9, 13 or 17 weeks. The mRNA and protein levels for LXRα and SREBP-1c were measured at each time point, as was fatty acid synthase (FAS) activity and the serum levels of free fatty acid (FFA) and triglyceride (TG). The mRNA and protein levels for LXRα and SREBP-1c, FAS activity and serum levels of FFA and TG all significantly increased from week 9 in the high-fat diet rats versus controls. In conclusion, a high-fat diet upregulates LXRα which, in turn, upregulates SREBP-1c, increasing the activity of FAS and FFA and accumulation of TG in hepatocytes. Thus, LXRα and SREBP-1c contribute to the development of NASH.
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Affiliation(s)
- Z-L Ai
- Department of Gastroenterology and Hepatology, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China
| | - C-H Zhu
- Department of Gastroenterology and Hepatology, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China
- Department of Gastroenterology and Hepatology, Hospital 309 of the People's Liberation Army, Beijing, China
| | - M Min
- Department of Gastroenterology and Hepatology, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China
| | - J Wang
- Department of Gastroenterology and Hepatology, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China
| | - C-H Lan
- Department of Gastroenterology and Hepatology, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China
| | - L-L Fan
- Department of Gastroenterology and Hepatology, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China
| | - W-J Sun
- Department of Gastroenterology and Hepatology, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China
| | - D-F Chen
- Department of Gastroenterology and Hepatology, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, China
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