Yeast protein-derived methionine alleviates ethanol-induced acute gastric mucosal injury by targeting TNF-α/NOS2 and modulating the NOD-like receptor signaling pathway

INTRODUCTION: Ethanol directly stimulates and damages the gastric mucosa, leading to impairment of the mucus-bicarbonate barrier and mechanical barrier, which is the primary factor of gastric ulcer formation. Yeast protein (YP), an emerging microbial food ingredient, has shown potential in mucosal protection. However, its bioactive components and underlying mechanisms remain unclear. OBJECTIVES: This study aims to evaluate the protective effect of YP hydrolyzed by papanin (YP-P) against ethanol-induced acute gastric mucosal injury, identify the key bioactive compound, and elucidate the molecular mechanism by which it alleviates gastric mucosal damage. METHODS: In this study, enzyme-linked immunosorbent assay (ELISA), immunofluorescence (IF), western blotting (WB), transmission electron microscopy (TEM) and other experimental techniques were used to evaluate the protective effects of YP-P by establishing ethanol-induced gastric mucosal injury models in vitro and in vivo. RNA sequencing, untargeted metabolomics, peptidomics, virtual screening, molecular docking, network pharmacology, proteomics, and multi-omics analysis techniques were used to determine the potential targets and molecular mechanisms of YP-P in alleviating gastric mucosal damage. Finally, the inhibition of bioactive compounds identified in YP on the nucleotide-binding oligomerization domain (NOD)-like receptor signaling pathway was verified through cell experiments. RESULTS: The protective effects of papain-hydrolyzed YP (YP-P) were demonstrated by establishing ethanol-induced gastric mucosal injury models in vitro and in vivo. Fractionation via centrifugation and ultrafiltration identified the component with molecular weight less than 5 kDa (YP-P < 5 kDa) as the primary protective fraction. Integrating multi-omics with virtual screening and network pharmacology, methionine (Met) was identified as the key bioactive compound within YP-P < 5 kDa. Mechanism studies revealed that Met alleviates ethanol-induced acute gastric mucosal injury by targeting tumor necrosis factor-α (TNF-α)/inducible nitrogen oxide synthase (NOS2) and modulating the NOD-like receptor signaling pathway. CONCLUSIONS: These findings highlight the protective effect of YP and its bioactive compound in the prevention and management of gastric mucosal injury, providing reference for their application as gastric mucosal protectants in functional ingredient.