Barroso Fernández, EmmaRodríguez-Rodríguez, RosalíaZarei, MohammadPizarro Delgado, JavierPlanavila Porta, AnaPalomer Tarridas, Francesc XavierVillarroya i Gombau, FrancescVázquez Carrera, Manuel2020-10-062020-10-062020-09-101478-811Xhttps://hdl.handle.net/2445/171056Background: Deficiency of mitochondrial sirtuin 3 (SIRT3), a NAD+ -dependent protein deacetylase that maintains redox status and lipid homeostasis, contributes to hepatic steatosis. In this study, we investigated additional mechanisms that might play a role in aggravating hepatic steatosis in Sirt3-deficient mice fed a high-fat diet (HFD). Methods: Studies were conducted in wild-type (WT) and Sirt3−/− mice fed a standard diet or a HFD and in SIRT3- knockdown human Huh-7 hepatoma cells. Results: Sirt3−/− mice fed a HFD presented exacerbated hepatic steatosis that was accompanied by decreased expression and DNA-binding activity of peroxisome proliferator-activated receptor (PPAR) α and of several of its target genes involved in fatty acid oxidation, compared to WT mice fed the HFD. Interestingly, Sirt3 deficiency in liver and its knockdown in Huh-7 cells resulted in upregulation of the nuclear levels of LIPIN1, a PPARα co-activator, and of the protein that controls its levels and localization, hypoxia-inducible factor 1α (HIF-1α). These changes were prevented by lipid exposure through a mechanism that might involve a decrease in succinate levels. Finally, Sirt3−/− mice fed the HFD showed increased levels of some proteins involved in lipid uptake, such as CD36 and the VLDL receptor. The upregulation in CD36 was confirmed in Huh-7 cells treated with a SIRT3 inhibitor or transfected with SIRT3 siRNA and incubated with palmitate, an effect that was prevented by the Nrf2 inhibitor ML385. Conclusion: These findings demonstrate new mechanisms by which Sirt3 deficiency contributes to hepatic steatosis13 p.application/pdfengcc-by (c) Barroso Fernández, Emma et al., 2020http://creativecommons.org/licenses/by/3.0/esMalalties del fetgeLípidsLiver diseasesLipidsinfo:eu-repo/semantics/article7034692020-10-06info:eu-repo/semantics/openAccess32912335