A Donkey Blood-Derived Bioactive Peptide (YPWTQ) Alleviates Insulin Resistance in HepG2 Cells Through Multi-Target Regulation of Glucose and Lipid Metabolism and Oxidative Stress

Background: Type 2 diabetes (T2DM) is a chronic metabolic disease closely associated with insulin resistance (IR) and disturbances in glucose and lipid metabolism. Bioactive peptides derived from food are attracting increasing research attention as candidates for nutritional supplements or functional food ingredients that improve metabolic health. This study evaluated the functional food-related properties of YPWTQ (CP4), a novel peptide derived from donkey blood, and its ability to alleviate insulin resistance in HepG2 cells. Methods: CP4 was characterized based on its hemolytic activity, stability under simulated gastrointestinal digestion conditions, inhibitory activity against α-glucosidase and Pancreatic lipase, and free radical scavenging capacity (DPPH·, ABTS+·, and O2−·). Its effects on glucolipid metabolism and oxidative stress were examined in a glucosamine-induced insulin-resistant HepG2 cell model. Candidate signaling pathways associated with CP4 treatment were explored through transcriptomic and metabolomic analyses, combined with RT-qPCR technology. Results: CP4 exhibited low hemolytic activity and remained stable after 4 h of simulated gastrointestinal digestion. It inhibited α-glucosidase and Pancreatic lipase and exhibited antioxidant activity. In insulin-resistant HepG2 cells, CP4 increased glucose consumption, glycogen content, and cell survival, while reducing triglyceride accumulation, malondialdehyde levels, and reactive oxygen species (ROS) production. Mult omics analysis indicates that these phenotypic effects may be associated with coordinated changes in the PI3K-Akt, AGE-RAGE, Rap1, and Ras signaling pathways, as well as related genes and metabolites. Conclusions: These findings suggest that CP4, as a food-derived bioactive peptide candidate, warrants further investigation into its potential applications in the field of metabolic health.