Discovery of ActRIIB antagonistic peptides from in vitro-digested chicken breast meat via an integrated Peptidomics and molecular docking approach

Sarcopenia and obesity are major global health challenges. This study investigated peptides from chicken breast meat via in vitro digestion as potent ActRIIB antagonists to promote myogenesis. The intestinal-phase digest collected at 120 min showed the highest degree of hydrolysis (65.99 % ± 4.00 %) and enhanced C2C12 proliferation (128.15 % ± 9.90 %). Peptidomics identified peptides mainly from myofibrillar proteins and metabolic enzymes. Molecular docking revealed key hydrogen-bonding residues, including Glu95, Pro117, Glu94, Thr93, Asn96 (Chain A), Ser97 (Chain L), and Ser59 (Chain H). Surface plasmon resonance showed that KEKLHVYKHIEK, EIKKEEKKEER, and DLENDKQQLDEK exhibited strong ActRIIB-binding affinity (KD: 0.514, 0.813, 1.91 μM). These peptides enhanced cell proliferation, inhibited myostatin signaling by reducing Smad2/3 phosphorylation, and upregulated MyoD expression. Molecular dynamics simulations (100 ns) indicated that DLENDKQQLDEK-ActRIIB and EIKKEEKKEER-ActRIIB complexes maintained a stable average number of 6 and 10 hydrogen bonds, respectively. Chicken breast-derived peptides thus represent promising functional food ingredients for combating muscle-wasting disorders.