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Mirza AH, Cui L, Zhang S, Liu P. Comparative proteomics reveals that lipid droplet-anchored mitochondria are more sensitive to cold in brown adipocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158992. [PMID: 34147658 DOI: 10.1016/j.bbalip.2021.158992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/04/2021] [Accepted: 06/09/2021] [Indexed: 10/21/2022]
Abstract
Brown adipose tissue (BAT) is specialized for uncoupled heat production through mitochondrion fueled majorly from fatty acids (FAs) of lipid droplets (LDs). How the interaction between the two organelles contributes the generation of heat remains elusive. Here, we report that LD-anchored mitochondria (LDAM) were observed in the BAT of mice raised at three different temperatures, 30 °C, 23 °C, and 6 °C. The biochemical analyses including Western blotting of electron transport chain subunits showed that LDAM were functional. Comparative proteomics analysis was conducted, which revealed differential expressions of proteins between LDAM and cytoplasmic mitochondria (CM) at different temperatures. Higher expressions of proteins at low temperature were observed for i) FA β-oxidation in LDAM including FA synthesis and uncoupling, ii) pseudo-futile cycle in CM, and iii) two shuttle systems: glycerol 3-phosphate in both CM and LDAM and citrate malate in CM. Together, these results suggest that LDs and LDAM form a preorganized and functional organelle complex that permits the rapid response to cold.
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Affiliation(s)
- Ahmed Hammad Mirza
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liujuan Cui
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Shuyan Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Pingsheng Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China.
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Li JM, Li LY, Qin X, Degrace P, Demizieux L, Limbu SM, Wang X, Zhang ML, Li DL, Du ZY. Inhibited Carnitine Synthesis Causes Systemic Alteration of Nutrient Metabolism in Zebrafish. Front Physiol 2018; 9:509. [PMID: 29867554 PMCID: PMC5954090 DOI: 10.3389/fphys.2018.00509] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/20/2018] [Indexed: 12/30/2022] Open
Abstract
Impaired mitochondrial fatty acid β-oxidation has been correlated with many metabolic syndromes, and the metabolic characteristics of the mammalian models of mitochondrial dysfunction have also been intensively studied. However, the effects of the impaired mitochondrial fatty acid β-oxidation on systemic metabolism in teleost have never been investigated. In the present study, we established a low-carnitine zebrafish model by feeding fish with mildronate as a specific carnitine synthesis inhibitor [0.05% body weight (BW)/d] for 7 weeks, and the systemically changed nutrient metabolism, including carnitine and triglyceride (TG) concentrations, fatty acid (FA) β-oxidation capability, and other molecular and biochemical assays of lipid, glucose, and protein metabolism, were measured. The results indicated that mildronate markedly decreased hepatic carnitine concentrations while it had no effect in muscle. Liver TG concentrations increased by more than 50% in mildronate-treated fish. Mildronate decreased the efficiency of liver mitochondrial β-oxidation, increased the hepatic mRNA expression of genes related to FA β-oxidation and lipolysis, and decreased the expression of lipogenesis genes. Mildronate decreased whole body glycogen content, increased glucose metabolism rate, and upregulated the expression of glucose uptake and glycolysis genes. Mildronate also increased whole body protein content and hepatic mRNA expression of mechanistic target of rapamycin (mtor), and decreased the expression of a protein catabolism-related gene. Liver, rather than muscle, was the primary organ targeted by mildronate. In short, mildronate-induced hepatic inhibited carnitine synthesis in zebrafish caused decreased mitochondrial FA β-oxidation efficiency, greater lipid accumulation, and altered glucose and protein metabolism. This reveals the key roles of mitochondrial fatty acid β-oxidation in nutrient metabolism in fish, and this low-carnitine zebrafish model could also be used as a novel fish model for future metabolism studies.
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Affiliation(s)
- Jia-Min Li
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
| | - Ling-Yu Li
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
| | - Xuan Qin
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Pascal Degrace
- Team Pathophysiology of Dyslipidemia, Faculty of Sciences Gabriel, INSERM UMR1231 "Lipides, Nutrition, Cancer," Université Bourgogne Franche-Comté, Dijon, France
| | - Laurent Demizieux
- Team Pathophysiology of Dyslipidemia, Faculty of Sciences Gabriel, INSERM UMR1231 "Lipides, Nutrition, Cancer," Université Bourgogne Franche-Comté, Dijon, France
| | - Samwel M Limbu
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China.,Department of Aquatic Sciences and Fisheries Technology, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Xin Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Mei-Ling Zhang
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
| | - Dong-Liang Li
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
| | - Zhen-Yu Du
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
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