Hydrogen sulfide rescues IFNγ/TNFα-induced intestinal epithelial barrier dysfunction by enhancing oxidative phosphorylation.

The intestinal epithelial barrier is essential for protection against pathogens and toxins while allowing nutrient and water absorption. Barrier dysfunction is increasingly recognized as a key pathophysiological mechanism in diseases affecting the gastrointestinal (GI) tract and distant organs. Hydrogen sulfide has emerged as an important regulator of intestinal homeostasis. This study investigates the effects of the H₂S-releasing compound 4-hydroxithiobenzamide (TBZ) on epithelial barrier integrity. Although TBZ did not prevent interferon-γ and tumor necrosis factor-α (IFN/TNF)-induced epithelial cell death, it reversed cytokine-induced increases in transepithelial permeability. Notably, TBZ alone increased paracellular permeability but normalized it under inflammatory conditions, indicating a context-dependent effect. H₂S-producing enzymes localized apically in IECs, suggesting subcellular regulation. Transcriptomic analysis identified oxidative phosphorylation as a pathway mediating TBZ’s effects. Functional studies confirmed that TBZ enhances oxidative phosphorylation, while inhibition of complex IV abolished barrier protection. In conclusion, our data indicate that hydrogen sulfide counteracts IFN/TNF-induced epithelial barrier dysfunction through transcriptional and functional enhancement of oxidative phosphorylation.