Emerging evidence suggests that mitochondrial dysfunction mediates the pathogenesis for non-alcoholic fatty liver disease (NAFLD). Hydroxytyrosol (HT) is a key component of extra virgin olive oil which can exert beneficial effects on NAFLD through modulating mitochondria. However, the mechanism of the impacts of HT still remains elusive. Thus, an in vivo and a series of in vitro experiments were carried out to examine the impacts of hydroxytyrosol (HT) on lipid metabolism and mitochondrial function in fish. For the in vivo experiment, two diets were produced to contain 10% and 16% fat as normal-fat and high-fat diets (NFD and HFD) and two additional diets were prepared by supplementing 200 mg/kg of HT to the NFD and HFD. The test diets were fed to triplicate groups of spotted seabass (Lateolabrax maculatus) juveniles for 8 weeks. The results showed that feeding HFD leads to increased fat deposition in the liver and induces oxidative stress, both of which were ameliorated by HT application. Furthermore, transmission electron microscopy revealed that HFD destroyed mitochondrial cristae and matrix and induced severe hydropic phenotype, while HT administration relieved these alterations. The results of in vitro studies using zebrafish liver cell line (ZFL) showed that HT promotes mitochondrial function and activates PINK1-mediated mitophagy. These beneficial effects of HT disappeared when the cells were treated with cyclosporin A (Csa) as a mitophagy inhibitor. Moreover, the PINK1-mediated mitophagy activation by HT was blocked when compound C (CC) was used as an AMPK inhibitor. In conclusion, our findings demonstrated that HT alleviates fat accumulation, oxidative stress and mitochondrial dysfunction, and its effects are deemed to be mediated via activating mitophagy through the AMPK/PINK1 pathway.

Key Laboratory for Feed Quality Testing and Safety Fisheries College Jimei University Xiamen 361021 China

Key Laboratory of Swine Nutrition and Feed Science of Fujian Province Fujian Aonong Biological Science and Technology Group Co Ltd Zhangzhou 363000 China

South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses Faculty of Fisheries and Protection of Waters University of South Bohemia in Ceske Budejovice Zatisi 728 2 389 25 Vodnany Czech Republic

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Ng M., Fleming T., Robinson M., Thomson B., Graetz N., Margono C., Mullany E.C., Biryukov S., Abbafati C., Abera S.F., et al. Global, regional, and national prevalence of overweight and obesity in children and adults during 1980–2013: A systematic analysis for the Global Burden of Disease Study 2013. Lancet. 2014;384:766–781. doi: 10.1016/S0140-6736(14)60460-8. PubMed DOI PMC

Angulo P. Obesity and Nonalcoholic Fatty Liver Disease. Nutr. Rev. 2007;65:57–63. doi: 10.1301/nr.2007.jun.S57-S63. PubMed DOI

Marchesini G., Bugianesi E., Forlani G., Cerrelli F., Lenzi M., Manini R., Natale S., Vanni E., Villanova N., Melchionda N., et al. Nonalcoholic fatty liver, steatohepatitis, and the metabolic syndrome. Hepatology. 2003;37:917–923. doi: 10.1053/jhep.2003.50161. PubMed DOI

Mantena S.K., King A.L., Andringa K.K., Eccleston H.B., Bailey S.M. Mitochondrial dysfunction and oxidative stress in the pathogenesis of alcohol- and obesity-induced fatty liver diseases. Free Radic. Biol. Med. 2008;44:1259–1272. doi: 10.1016/j.freeradbiomed.2007.12.029. PubMed DOI PMC

Begriche K., Massart J., Robin M.-A., Bonnet F., Fromenty B. Mitochondrial Adaptations and Dysfunctions in Nonalcoholic Fatty Liver Disease. Hepatology. 2013;58:1497–1507. doi: 10.1002/hep.26226. PubMed DOI

Li X., Shi Z., Zhu Y., Shen T., Wang H., Shui G., Loor J.J., Fang Z., Chen M., Wang X., et al. Cyanidin-3-O-glucoside improves non-alcoholic fatty liver disease by promoting PINK1-mediated mitophagy in mice. Br. J. Pharmacol. 2020;177:3591–3607. doi: 10.1111/bph.15083. PubMed DOI PMC

Shadel G.S., Horvath T.L. Mitochondrial ROS Signaling in Organismal Homeostasis. Cell. 2015;163:560–569. doi: 10.1016/j.cell.2015.10.001. PubMed DOI PMC

Dabravolski S.A., Bezsonov E.E., Orekhov A.N. The role of mitochondria dysfunction and hepatic senescence in NAFLD development and progression. Biomed. Pharmacother. 2021;142:112041. doi: 10.1016/j.biopha.2021.112041. PubMed DOI

Hao J., Shen W., Yu G., Jia H., Li X., Feng Z., Wang Y., Weber P., Wertz K., Sharman E., et al. Hydroxytyrosol promotes mitochondrial biogenesis and mitochondrial function in 3T3-L1 adipocytes. J. Nutr. Biochem. 2010;21:634–644. doi: 10.1016/j.jnutbio.2009.03.012. PubMed DOI

Liu J.K., Ames B.N. Reducing mitochondrial decay with mitochondrial nutrients to delay and treat cognitive dysfunction, Alzheimer’s disease, and Parkinson’s disease. Nutr. Neurosci. 2005;8:67–89. doi: 10.1080/10284150500047161. PubMed DOI

Wang J., Tian S., Wang J., Zhu W. Early galactooligosaccharide intervention alters the metabolic profile, improves the antioxidant capacity of mitochondria and activates the AMPK/Nrf2 signaling pathway in suckling piglet liver. Food Funct. 2020;11:7280–7292. doi: 10.1039/D0FO01486A. PubMed DOI

Lu K.-L., Wang L.-N., Zhang D.-D., Liu W.-B., Xu W.-N. Berberine attenuates oxidative stress and hepatocytes apoptosis via protecting mitochondria in blunt snout bream Megalobrama amblycephala fed high-fat diets. Fish. Physiol. Biochem. 2017;43:65–76. doi: 10.1007/s10695-016-0268-5. PubMed DOI

Tuck K.L., Hayball P.J. Major phenolic compounds in olive oil: Metabolism and health effects. J. Nut. Biochem. 2002;13:636–644. doi: 10.1016/S0955-2863(02)00229-2. PubMed DOI

Liu Z., Wang N., Ma Y., Wen D. Hydroxytyrosol Improves Obesity and Insulin Resistance by Modulating Gut Microbiota in High-Fat Diet-Induced Obese Mice. Front. Microbiol. 2019;10:390. doi: 10.3389/fmicb.2019.00390. PubMed DOI PMC

Dong Y., Xia T., Yu M., Wang L., Song K., Zhang C., Lu K. Hydroxytyrosol Attenuates High-Fat-Diet-Induced Oxidative Stress, Apoptosis and Inflammation of Blunt Snout Bream (Megalobrama amblycephala) through Its Regulation of Mitochondrial Homeostasis. Fishes. 2022;7:78. doi: 10.3390/fishes7020078. DOI

Zhu L., Liu Z., Feng Z., Hao J., Shen W., Li X., Sun L., Sharman E., Wang Y., Wertz K., et al. Hydroxytyrosol protects against oxidative damage by simultaneous activation of mitochondrial biogenesis and phase II detoxifying enzyme systems in retinal pigment epithelial cells. J. Nut. Biochem. 2010;21:1089–1098. doi: 10.1016/j.jnutbio.2009.09.006. PubMed DOI

Birsoy K., Festuccia W.T., Laplante M. A comparative perspective on lipid storage in animals. J. Cell Sci. 2013;126:1541–1552. doi: 10.1242/jcs.104992. PubMed DOI

Li Y., Ding W., Li C.-Y., Liu Y. HLH-11 modulates lipid metabolism in response to nutrient availability. Nat. Commun. 2020;11:5959. doi: 10.1038/s41467-020-19754-1. PubMed DOI PMC

Asaoka Y., Terai S., Sakaida I., Nishina H. The expanding role of fish models in understanding non-alcoholic fatty liver disease. Dis. Model. Mech. 2013;6:905–914. doi: 10.1242/dmm.011981. PubMed DOI PMC

Oka T., Nishimura Y., Zang L., Hirano M., Shimada Y., Wang Z., Umemoto N., Kuroyanagi J., Nishimura N., Tanaka T. Diet-induced obesity in zebrafish shares common pathophysiological pathways with mammalian obesity. BMC Physiol. 2010;10:21. doi: 10.1186/1472-6793-10-21. PubMed DOI PMC

Schlegel A., Stainier D.Y.R. Lessons from “lower” organisms: What worms, flies, and zebrafish can teach us about human energy metabolism. PLoS Genet. 2007;3:2037–2048. doi: 10.1371/journal.pgen.0030199. PubMed DOI PMC

Zhou W., Rahimnejad S., Lu K., Wang L., Liu W. Effects of berberine on growth, liver histology, and expression of lipid-related genes in blunt snout bream (Megalobrama amblycephala) fed high-fat diets. Fish. Physiol. Biochem. 2019;45:83–91. doi: 10.1007/s10695-018-0536-7. PubMed DOI

Dong Y.-Z., Xia T., Lin J.-B., Wang L., Song K., Zhang C.-X. Quercetin Attenuates High-Fat Diet-Induced Excessive Fat Deposition of Spotted Seabass (Lateolabrax maculatus) Through the Regulatory for Mitochondria and Endoplasmic Reticulum. Front. Mar. Sci. 2021;8:746811. doi: 10.3389/fmars.2021.746811. DOI

Folch J., Lees M., Sloane Stanley G.H. A simple method for the isolation and purification of total lipides from animal tissues. J. Biol. Chem. 1957;226:497–509. doi: 10.1016/S0021-9258(18)64849-5. PubMed DOI

Zhou W., Rahimnejad S., Tocher D.R., Lu K., Zhang C., Sun Y. Metformin attenuates lipid accumulation in hepatocytes of blunt snout bream (Megalobrama amblycephala) via activation of AMP-activated protein kinase. Aquaculture. 2019;499:90–100. doi: 10.1016/j.aquaculture.2018.09.028. DOI

Dong Y.-Z., Li L., Espe M., Lu K.-L., Rahimnejad S. Hydroxytyrosol Attenuates Hepatic Fat Accumulation via Activating Mitochondrial Biogenesis and Autophagy through the AMPK Pathway. J. Agric. Food Chem. 2020;68:9377–9386. doi: 10.1021/acs.jafc.0c03310. PubMed DOI

Cao K., Xu J., Zou X., Li Y., Chen C., Zheng A., Li H., Li H., Szeto I.M.-Y., Shi Y., et al. Hydroxytyrosol prevents diet-induced metabolic syndrome and attenuates mitochondrial abnormalities in obese mice. Free Radic. Biol. Med. 2014;67:396–407. doi: 10.1016/j.freeradbiomed.2013.11.029. PubMed DOI

Rueda-Jasso R., Conceicao L.E.C., Dias J., De Coen W., Gomes E., Rees J.F., Soares F., Dinis M.T., Sorgeloos P. Effect of dietary non-protein energy levels on condition and oxidative status of Senegalese sole (Solea senegalensis) juveniles. Aquaculture. 2004;231:417–433. doi: 10.1016/S0044-8486(03)00537-4. DOI

Fabiani R., Rosignoli P., De Bartolomeo A., Fuccelli R., Servili M., Montedoro G.F., Morozzi G. Oxidative DNA damage is prevented by extracts of olive oil, hydroxytyrosoll, and other olive phenolic compounds in human blood mononuclear cells and HL60 cells. J. Nutr. 2008;138:1411–1416. doi: 10.1093/jn/138.8.1411. PubMed DOI

Martín M.A., Ramos S., Granado-Serrano A.B., Rodríguez-Ramiro I., Trujillo M., Bravo L., Goya L. Hydroxytyrosol induces antioxidant/detoxificant enzymes and Nrf2 translocation via extracellular regulated kinases and phosphatidylinositol-3-kinase/protein kinase B pathways in HepG2 cells. Mol. Nutr. Food Res. 2010;54:956–966. doi: 10.1002/mnfr.200900159. PubMed DOI

Zou X., Feng Z., Li Y., Wang Y., Wertz K., Weber P., Fu Y., Liu J. Stimulation of GSH synthesis to prevent oxidative stress-induced apoptosis by hydroxytyrosol in human retinal pigment epithelial cells: Activation of Nrf2 and JNK-p62/SQSTM1 pathways. J. Nutr. Biochem. 2012;23:994–1006. doi: 10.1016/j.jnutbio.2011.05.006. PubMed DOI

Zhao L., Zou X., Feng Z., Luo C., Liu J., Li H., Chang L., Wang H., Li Y., Long J., et al. Evidence for association of mitochondrial metabolism alteration with lipid accumulation in aging rats. Exp. Gerontol. 2014;56:3–12. doi: 10.1016/j.exger.2014.02.001. PubMed DOI

Spangenburg E.E., Pratt S.J.P., Wohlers L.M., Lovering R.M. Use of BODIPY (493/503) to Visualize Intramuscular Lipid Droplets in Skeletal Muscle. J. Biomed. Biotechnol. 2011;2011:598358. doi: 10.1155/2011/598358. PubMed DOI PMC

Bishop D.J., Granata C., Eynon N. Can we optimise the exercise training prescription to maximise improvements in mitochondria function and content? BBA-Gen. Subj. 2014;1840:1266–1275. doi: 10.1016/j.bbagen.2013.10.012. PubMed DOI

Antoine T., Fisher N., Amewu R., Oneill P.M., Ward S.A., Biagini G.A. Rapid kill of malaria parasites by artemisinin and semi-synthetic endoperoxides involves ROS-dependent depolarization of the membrane potential. J. Antimicrob. Chemoth. 2014;69:1005–1016. doi: 10.1093/jac/dkt486. PubMed DOI PMC

Weijler A.M., Schmidinger B., Kapiotis S., Laggner H., Hermann M. Oleic acid induces the novel apolipoprotein O and reduces mitochondrial membrane potential in chicken and human hepatoma cells. Biochimie. 2018;147:136–142. doi: 10.1016/j.biochi.2018.02.003. PubMed DOI

Palikaras K., Tavernarakis N. Mitochondrial homeostasis: The interplay between mitophagy and mitochondrial biogenesis. Exp. Gerontol. 2014;56:182–188. doi: 10.1016/j.exger.2014.01.021. PubMed DOI

Wible D.J., Bratton S.B. Reciprocity in ROS and autophagic signaling. Cur. Opin. Toxicol. 2018;7:28–36. doi: 10.1016/j.cotox.2017.10.006. PubMed DOI PMC

Youle R.J., Narendra D.P. Mechanisms of mitophagy. Nat. Rev. Mol. Cell Bio. 2011;12:9–14. doi: 10.1038/nrm3028. PubMed DOI PMC

Yang Z., Klionsky D.J. Eaten alive: A history of macroautophagy. Nat. Cell Bio. 2010;12:814–822. doi: 10.1038/ncb0910-814. PubMed DOI PMC

Feng Y., He D., Yao Z., Klionsky D.J. The machinery of macroautophagy. Cell Res. 2014;24:24–41. doi: 10.1038/cr.2013.168. PubMed DOI PMC

Dengjel J., Abeliovich H. Roles of mitophagy in cellular physiology and development. Cell Tissue Res. 2017;367:95–109. doi: 10.1007/s00441-016-2472-0. PubMed DOI

Lazarou M., Sliter D.A., Kane L.A., Sarraf S.A., Wang C., Burman J.L., Sideris D.P., Fogel A.I., Youle R.J. The ubiquitin kinase PINK1 recruits autophagy receptors to induce mitophagy. Nature. 2015;524:309–314. doi: 10.1038/nature14893. PubMed DOI PMC

Narendra D.P., Jin S.M., Tanaka A., Suen D.-F., Gautier C.A., Shen J., Cookson M.R., Youle R.J. PINK1 Is Selectively Stabilized on Impaired Mitochondria to Activate Parkin. PLoS Biol. 2010;8:e1000298. doi: 10.1371/journal.pbio.1000298. PubMed DOI PMC

Sin J., Andres A.M., Taylor D.J.R., Weston T., Hiraumi Y., Stotland A., Kim B.J., Huang C., Doran K.S., Gottlieb R.A. Mitophagy is required for mitochondrial biogenesis and myogenic differentiation of C2C12 myoblasts. Autophagy. 2016;12:369–380. doi: 10.1080/15548627.2015.1115172. PubMed DOI PMC

You M., Rogers C.Q. Adiponectin: A Key Adipokine in Alcoholic Fatty Liver. Exp. Bio. Med. 2009;234:850–859. doi: 10.3181/0902-MR-61. PubMed DOI

Hardie D.G., Ross F.A., Hawley S.A. AMPK: A nutrient and energy sensor that maintains energy homeostasis. Nat. Rev. Mol. Cell Bio. 2012;13:251–262. doi: 10.1038/nrm3311. PubMed DOI PMC

Hardie D.G. AMP-activated protein kinase: A master switch in glucose and lipid metabolism. Rev. Endocr. Metab. Dis. 2004;5:119–125. doi: 10.1023/B:REMD.0000021433.63915.bb. PubMed DOI

Wang B., Nie J., Wu L., Hu Y., Wen Z., Dong L., Zou M.H., Chen C., Wang D.W. AMPKalpha2 Protects Against the Development of Heart Failure by Enhancing Mitophagy via PINK1 Phosphorylation. Circ. Res. 2018;122:712–729. doi: 10.1161/CIRCRESAHA.117.312317. PubMed DOI PMC

Dietary n-3/n-6 polyunsaturated fatty acid ratio modulates growth performance in spotted seabass (Lateolabrax maculatus) through regulating lipid metabolism, hepatic antioxidant capacity and intestinal health