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Xiao F, Chen C, Zhang W, Wang J, Wu K. FOXO3/Rab7-Mediated Lipophagy and Its Role in Zn-Induced Lipid Metabolism in Yellow Catfish ( Pelteobagrus fulvidraco). Genes (Basel) 2024; 15:334. [PMID: 38540393 PMCID: PMC10969980 DOI: 10.3390/genes15030334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 06/14/2024] Open
Abstract
Lipophagy is a selective autophagy that regulates lipid metabolism and reduces hepatic lipid deposition. However, the underlying mechanism has not been understood in fish. In this study, we used micronutrient zinc (Zn) as a regulator of autophagy and lipid metabolism and found that Ras-related protein 7 (rab7) was involved in Zn-induced lipophagy in hepatocytes of yellow catfish Pelteobagrus pelteobagrus. We then characterized the rab7 promoter and identified binding sites for a series of transcription factors, including Forkhead box O3 (FOXO3). Site mutation experiments showed that the -1358/-1369 bp FOXO3 binding site was responsible for Zn-induced transcriptional activation of rab7. Further studies showed that inhibition of rab7 significantly inhibited Zn-induced lipid degradation by lipophagy. Moreover, rab7 inhibitor also mitigated the Zn-induced increase of cpt1α and acadm expression. Our results suggested that Zn exerts its lipid-lowering effect partly through rab7-mediated lipophagy and FA β-oxidation in hepatocytes. Overall, our findings provide novel insights into the FOXO3/rab7 axis in lipophagy regulation and enhance the understanding of lipid metabolism by micronutrient Zn, which may help to reduce excessive lipid accumulation in fish.
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Affiliation(s)
- Fei Xiao
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (F.X.); (C.C.); (J.W.)
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 510642, China
| | - Chuan Chen
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (F.X.); (C.C.); (J.W.)
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 510642, China
| | - Wuxiao Zhang
- College of Marine and Biology Engineering, Yancheng Institute of Technology, Yancheng 224051, China;
| | - Jiawei Wang
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (F.X.); (C.C.); (J.W.)
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 510642, China
| | - Kun Wu
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (F.X.); (C.C.); (J.W.)
- Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 510642, China
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Xi L, Zhai G, Liu Y, Gong Y, Lu Q, Zhang Z, Liu H, Jin J, Zhu X, Yin Z, Xie S, Han D. Attenuated glucose uptake promotes catabolic metabolism through activated AMPK signaling and impaired insulin signaling in zebrafish. Front Nutr 2023; 10:1187283. [PMID: 37305084 PMCID: PMC10250679 DOI: 10.3389/fnut.2023.1187283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 05/04/2023] [Indexed: 06/13/2023] Open
Abstract
Glucose metabolism in fish remains a controversial area of research as many fish species are traditionally considered glucose-intolerant. Although energy homeostasis remodeling has been observed in fish with inhibited fatty acid β-oxidation (FAO), the effects and mechanism of the remodeling caused by blocked glucose uptake remain poorly understood. In this study, we blocked glucose uptake by knocking out glut2 in zebrafish. Intriguingly, the complete lethality, found in Glut2-null mice, was not observed in glut2-/- zebrafish. Approxiamately 30% of glut2-/- fish survived to adulthood and could reproduce. The maternal zygotic mutant glut2 (MZglut2) fish exhibited growth retardation, decreased blood and tissue glucose levels, and low locomotion activity. The decreased pancreatic β-cell numbers and insulin expression, as well as liver insulin receptor a (insra), fatty acid synthesis (chrebp, srebf1, fasn, fads2, and scd), triglyceride synthesis (dgat1a), and muscle mechanistic target of rapamycin kinase (mtor) of MZglut2 zebrafish, suggest impaired insulin-dependent anabolic metabolism. Upregulated expression of lipolysis (atgl and lpl) and FAO genes (cpt1aa and cpt1ab) in the liver and proteolysis genes (bckdk, glud1b, and murf1a) in muscle were observed in the MZglut2 zebrafish, as well as elevated levels of P-AMPK proteins in both the liver and muscle, indicating enhanced catabolic metabolism associated with AMPK signaling. In addition, decreased amino acids and elevated carnitines of the MZglut2 zebrafish supported the decreased protein and lipid content of the whole fish. In summary, we found that blocked glucose uptake impaired insulin signaling-mediated anabolism via β-cell loss, while AMPK signaling-mediated catabolism was enhanced. These findings reveal the mechanism of energy homeostasis remodeling caused by blocked glucose uptake, which may be a potential strategy for adapting to low glucose levels.
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Affiliation(s)
- Longwei Xi
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Gang Zhai
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yulong Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yulong Gong
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Qisheng Lu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhimin Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Haokun Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Junyan Jin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoming Zhu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhan Yin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Hubei Hongshan Laboratory, Huazhong Agriculture University, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Wuhan, China
| | - Shouqi Xie
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Wuhan, China
| | - Dong Han
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Hubei Hongshan Laboratory, Huazhong Agriculture University, Wuhan, China
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Li RX, Chen LY, Limbu SM, Qian YC, Zhou WH, Chen LQ, Luo Y, Qiao F, Zhang ML, Du ZY. High cholesterol intake remodels cholesterol turnover and energy homeostasis in Nile tilapia ( Oreochromis niloticus). MARINE LIFE SCIENCE & TECHNOLOGY 2023; 5:56-74. [PMID: 37073330 PMCID: PMC10077235 DOI: 10.1007/s42995-022-00158-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 12/08/2022] [Indexed: 05/03/2023]
Abstract
The roles of dietary cholesterol in fish physiology are currently contradictory. The issue reflects the limited studies on the metabolic consequences of cholesterol intake in fish. The present study investigated the metabolic responses to high cholesterol intake in Nile tilapia (Oreochromis niloticus), which were fed with four cholesterol-contained diets (0.8, 1.6, 2.4 and 3.2%) and a control diet for eight weeks. All fish-fed cholesterol diets showed increased body weight, but accumulated cholesterol (the peak level was in the 1.6% cholesterol group). Then, we selected 1.6% cholesterol and control diets for further analysis. The high cholesterol diet impaired liver function and reduced mitochondria number in fish. Furthermore, high cholesterol intake triggered protective adaptation via (1) inhibiting endogenous cholesterol synthesis, (2) elevating the expression of genes related to cholesterol esterification and efflux, and (3) promoting chenodeoxycholic acid synthesis and efflux. Accordingly, high cholesterol intake reshaped the fish gut microbiome by increasing the abundance of Lactobacillus spp. and Mycobacterium spp., both of which are involved in cholesterol and/or bile acids catabolism. Moreover, high cholesterol intake inhibited lipid catabolic activities through mitochondrial β-oxidation, and lysosome-mediated lipophagy, and depressed insulin signaling sensitivity. Protein catabolism was elevated as a compulsory response to maintain energy homeostasis. Therefore, although high cholesterol intake promoted growth, it led to metabolic disorders in fish. For the first time, this study provides evidence for the systemic metabolic response to high cholesterol intake in fish. This knowledge contributes to an understanding of the metabolic syndromes caused by high cholesterol intake or deposition in fish. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00158-7.
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Affiliation(s)
- Rui-Xin Li
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241 China
| | - Ling-Yun Chen
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241 China
| | - Samwel M. Limbu
- Department of Aquaculture Technology, School of Aquatic Sciences and Fisheries Technology, University of Dar es Salaam, P. O. Box 60091, Dar es Salaam, Tanzania
| | - Yu-Cheng Qian
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241 China
| | - Wen-Hao Zhou
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241 China
| | - Li-Qiao Chen
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241 China
| | - Yuan Luo
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241 China
| | - Fang Qiao
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241 China
| | - Mei-Ling Zhang
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241 China
| | - Zhen-Yu Du
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241 China
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Gao H, Fan X, Wu QC, Chen C, Xiao F, Wu K. Structural and Functional Analysis of SHP Promoter and Its Transcriptional Response to FXR in Zn-Induced Changes to Lipid Metabolism. Int J Mol Sci 2022; 23:ijms23126523. [PMID: 35742980 PMCID: PMC9224202 DOI: 10.3390/ijms23126523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 02/04/2023] Open
Abstract
Zinc alleviates hepatic lipid deposition, but the transcriptional regulatory mechanisms are still unclear. In this study, we characterized the promoter of an SHP (short heterodimer partner) in a teleost Pelteobagrus fulvidraco. The binding sites of an FXR (farnesoid X receptor) were predicted by the SHP promoter, indicating that the FXR mediated its transcriptional activity. The site mutagenesis and the EMSA (electrophoretic mobility shift assay) found that the -375/-384 bp FXR site on the SHP promoter was the functional binding locus responsible for the Zn-induced transcriptional activation. A further study of yellow catfish hepatocytes suggested that the activation of the FXR/SHP is responsible for the effect of Zn on the decreasing lipid content. Thus, this study provides direct evidence of the interaction between the FXR and SHP promoter in fish, and accordingly elucidates the potential transcriptional mechanism by which Zn reduces hepatic lipid accumulation.
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Affiliation(s)
- Han Gao
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (H.G.); (X.F.); (Q.-C.W.); (C.C.); (F.X.)
| | - Xing Fan
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (H.G.); (X.F.); (Q.-C.W.); (C.C.); (F.X.)
| | - Qi-Chun Wu
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (H.G.); (X.F.); (Q.-C.W.); (C.C.); (F.X.)
| | - Chuan Chen
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (H.G.); (X.F.); (Q.-C.W.); (C.C.); (F.X.)
| | - Fei Xiao
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (H.G.); (X.F.); (Q.-C.W.); (C.C.); (F.X.)
| | - Kun Wu
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; (H.G.); (X.F.); (Q.-C.W.); (C.C.); (F.X.)
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region on Marine Bioresource Conservation and Exploitation, Guangzhou 510642, China
- Correspondence: or
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Tian J, Du Y, Yu E, Lei C, Xia Y, Jiang P, Li H, Zhang K, Li Z, Gong W, Xie J, Wang G. Prostaglandin 2α Promotes Autophagy and Mitochondrial Energy Production in Fish Hepatocytes. Cells 2022; 11:cells11121870. [PMID: 35740999 PMCID: PMC9220818 DOI: 10.3390/cells11121870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/23/2022] [Accepted: 06/02/2022] [Indexed: 12/10/2022] Open
Abstract
Fatty liver, characterized by excessive lipid droplet (LD) accumulation in hepatocytes, is a common physiological condition in humans and aquaculture species. Lipid mobilization is an important strategy for modulating the number and size of cellular LDs. Cyclooxygenase (COX)-mediated arachidonic acid derivatives are known to improve lipid catabolism in fish; however, the specific derivatives remain unknown. In the present study, we showed that serum starvation induced LD degradation via autophagy, lipolysis, and mitochondrial energy production in zebrafish hepatocytes, accompanied by activation of the COX pathway. The cellular concentration of PGF2α, but not other prostaglandins, was significantly increased. Administration of a COX inhibitor or interference with PGF2α synthase abolished serum deprivation-induced LD suppression, LD–lysosome colocalization, and expression of autophagic genes. Additionally, exogenous PGF2α suppressed the accumulation of LDs, promoted the accumulation of lysosomes with LD and the autophagy marker protein LC3A/B, and augmented the expression of autophagic genes. Moreover, PGF2α enhanced mitochondrial accumulation and ATP production, and increased the transcript levels of β-oxidation- and mitochondrial respiratory chain-related genes. Collectively, these findings demonstrate that the COX pathway is implicated in lipid degradation induced by energy deprivation, and that PGF2α is a key molecule triggering autophagy, lipolysis, and mitochondrial development in zebrafish hepatocytes.
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Affiliation(s)
- Jingjing Tian
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Yihui Du
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Ermeng Yu
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Caixia Lei
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Yun Xia
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Peng Jiang
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Hongyan Li
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Kai Zhang
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Zhifei Li
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Wangbao Gong
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Jun Xie
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
- Correspondence: (J.X.); (G.W.)
| | - Guangjun Wang
- Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China; (J.T.); (Y.D.); (E.Y.); (C.L.); (Y.X.); (P.J.); (H.L.); (K.Z.); (Z.L.); (W.G.)
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
- Correspondence: (J.X.); (G.W.)
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Li L, Liu Y, Liu X, Zheng N, Gu Y, Song Y, Wang X. Regulatory roles of external cholesterol in human airway epithelial mitochondrial function through STARD3 signalling. Clin Transl Med 2022; 12:e902. [PMID: 35678098 PMCID: PMC9178408 DOI: 10.1002/ctm2.902] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/11/2022] [Accepted: 05/11/2022] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Hypercholesterolemia is found in patients with chronic lung inflammation, during which airway epithelial cells play important roles in maintenance of inflammatory responses to pathogens. The present study aims at molecular mechanisms by which cholesterol changes airway epithelial sensitivity in response to smoking. METHODS Human bronchial epithelial cells (HBEs) were stimulated with cigarette smoke extract (CSE) and mice were exposed to CS/lipopolysaccharide (LPS) as models in vitro and in vivo. Severe COPD patients and healthy volunteers were also enrolled and the level of cholesterol in plasma was detected by metabolomics. Filipin III and elisa kits were used to stain free cholesterol. Mitochondrial function was detected by mitotracker green, mitotracker green, and Seahorse. Mitochondrial morphology was detected by high content screening and electron microscopy. The mRNA and protein levels of mitochondrial dynamics-related proteins were detected by RT-qPCR and Western blot,respectively. BODIPY 493/503 was used to stain lipid droplets. Lipidomics was used to detect intracellular lipid components. The mRNA level of interleukin (IL)-6 and IL-8 were detected by RT-qPCR. RESULTS We found that the cholesterol overload was associated with chronic obstructive pulmonary disease (COPD) and airway epithelia-driven inflammation, evidenced by hypercholesterolemia in patients with COPD and preclinical models, alteration of lipid metabolism-associated genes in CSE-induced airway epithelia and production of ILs. External cholesterol altered airway epithelial sensitivity of inflammation in response to CSE, through the regulation of STARD3-MFN2 pathway, cholesterol re-distribution, altered transport and accumulation of cholesterol, activities of lipid transport regulators and disorder of mitochondrial function and dynamics. MFN2 down-regulation increased airway epithelial sensitivity and production of ILs after smoking, at least partially by injuring fatty acid oxidation and activating mTOR phosphorylation. CONCLUSIONS Our data provide new insights for understanding molecular mechanisms of cholesterol-altered airway epithelial inflammation and for developing diagnostic biomarkers and therapeutic targets to improve patient outcomes.
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Affiliation(s)
- Liyang Li
- Department of Pulmonary and Critical Care Medicine, Zhongshan HospitalFudan University Shanghai Medical CollegeShanghaiChina
| | - Yifei Liu
- Center of Molecular Diagnosis and TherapyThe Second Hospital of Fujian Medical UniversityQuanzhouFujianChina
| | - Xuanqi Liu
- Shanghai Institute of Clinical BioinformaticsShanghaiChina
| | - Nannan Zheng
- Department of Pulmonary and Critical Care Medicine, Zhongshan HospitalFudan University Shanghai Medical CollegeShanghaiChina
| | - Yutong Gu
- Department of Pulmonary and Critical Care Medicine, Zhongshan HospitalFudan University Shanghai Medical CollegeShanghaiChina
| | - Yuanlin Song
- Department of Pulmonary and Critical Care Medicine, Zhongshan HospitalFudan University Shanghai Medical CollegeShanghaiChina
| | - Xiangdong Wang
- Department of Pulmonary and Critical Care Medicine, Zhongshan HospitalFudan University Shanghai Medical CollegeShanghaiChina
- Shanghai Institute of Clinical BioinformaticsShanghaiChina
- Shanghai Engineering Research for AI Technology for Cardiopulmonary DiseasesShanghaiChina
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7
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Xu C, Fan J. Links between autophagy and lipid droplet dynamics. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2848-2858. [PMID: 35560198 DOI: 10.1093/jxb/erac003] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/06/2022] [Indexed: 06/15/2023]
Abstract
Autophagy is a catabolic process in which cytoplasmic components are delivered to vacuoles or lysosomes for degradation and nutrient recycling. Autophagy-mediated degradation of membrane lipids provides a source of fatty acids for the synthesis of energy-rich, storage lipid esters such as triacylglycerol (TAG). In eukaryotes, storage lipids are packaged into dynamic subcellular organelles, lipid droplets. In times of energy scarcity, lipid droplets can be degraded via autophagy in a process termed lipophagy to release fatty acids for energy production via fatty acid β-oxidation. On the other hand, emerging evidence suggests that lipid droplets are required for the efficient execution of autophagic processes. Here, we review recent advances in our understanding of metabolic interactions between autophagy and TAG storage, and discuss mechanisms of lipophagy. Free fatty acids are cytotoxic due to their detergent-like properties and their incorporation into lipid intermediates that are toxic at high levels. Thus, we also discuss how cells manage lipotoxic stresses during autophagy-mediated mobilization of fatty acids from lipid droplets and organellar membranes for energy generation.
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Affiliation(s)
- Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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