Lower H2S-generating enzyme levels and persulfidation-mediated protein protection characterize metabolic dysfunction-associated steatohepatitis

Metabolic dysfunction–associated steatohepatitis (MASH), marked by hepatic steatosis and inflammation, is a major risk for cirrhosis and liver cancer. Obesity-induced oxidative stress plays a central role in MASH promoting protein damage and dysfunction. Cysteine persulfidation (PSSH), a post-translational modification regulated by hydrogen sulfide (H2S), is involved in protein stability and cellular protection. However, the role of PSSH in MASH is poorly understood. We found that H2S-producing enzymes are downregulated in livers with fibrosis and inflammation, leading to decreased hepatic PSSH. Using dimedone-switch-based mass spectrometry, we mapped the alterations in the liver persulfidome during diet-induced fibrosis and inflammation. While the levels of H2S-producing enzymes dropped, some proteins, including protein tyrosine phosphatases (PTPs) and redox regulators, showed increased PSSH. This change suggests that H2S-mediated persulfidation helps protect proteins from oxidative damage. Overall, decreased H2S enzyme expression and reduced PSSH may impair protection against oxidative stress, contributing to liver dysfunction in obesity.