The hepatic compensatory response to elevated systemic sulfide impairs medium chain fat oxidation and promotes diabetes

Impaired hepatic glucose and lipid metabolism are hallmarks of type 2 diabetes. Increased sulfide production from cysteine, or sulfide donor compounds, may beneficially regulate hepatic metabolism. Disposal of sulfide through the sulfide oxidation pathway (SOP) is critical for maintaining sulfide within a safe physiological range. We show that mice lacking the liver enriched mitochondrial SOP enzyme thiosulfate sulfur transferase (Tst ko mice) exhibit high circulating sulfide, increased gluconeogenesis, hypertriglyceridemia and fatty liver, despite wholebody insulin sensitisation. Unexpectedly, hepatic sulfide levels were normal in Tst ko mice, a result of homeostatic induction of mitochondrial sulfide disposal and glutathione excretion associated with net suppression of protein persulfidation and nuclear respiratory factor 2 target proteins. Proteomic and persulfidomic profiling converged on hepatic lipid metabolism, revealing a deficit in medium chain fatty acid oxidation in Tst ko mice. In conclusion our findings have implications for sulfide donor strategies in the context of liver function and metabolic disease.