Fig. 7

Potential new mechanisms by which Sirt3 deficiency promotes hepatic steatosis in mice fed a HFD. Exposure to a HFD reduces Sirt3 and contributes to triglyceride accumulation in the liver. However, hepatic lipid accumulation is attenuated by the activation of an adaptive mechanism involving an increase in nuclear HIF-1α and Lipin 1. Longer exposures to a HFD exacerbates Sirt3 decrease leading to higher uptake of lipids through an Nrf-2 mediated increase in CD36 and VLDLR. This results in a higher increase in fatty acid accumulation, which in turn reduces succinate levels, ultimately suppressing the adaptive increase in HIF-1α and Lipin 1. FAO: Fatty acid oxidation