A multifunctional fungal defensin bladesin loaded-hydrogel for accelerated infectious wound healing

Wound management is significantly challenged by drug-resistant bacterial infections. In this study, a novel fungal defensin peptide derived from Blastomyces dermatitis was identified. The full-length peptide named bladesin was composed of 116 amino acids containing three regions: signal peptide, pro-peptide, and mature peptide. Sequence and structural analysis revealed that the linear mature peptide (reduced type) was consisted of 38 amino acids. The mature bladesin contains three intramolecular disulfide bonds (Cys4-Cys29, Cys14-Cys35 and Cys18-Cys37) and can form a characteristic cysteine-stabilized alpha-beta motif in the native state. In vitro studies demonstrated it exhibited potent antibacterial activity against Gram-positive pathogens with minimum inhibitory concentrations (MICs) ranging from 4 to 32 μM. Furthermore, bladesin was found to promote the proliferation of NIH/3 T3 fibroblasts cells. Using the Poloxamer 407 as the thermosensitive matrix, a bladesin-loaded sustained-release hydrogel was successfully prepared. In vivo experiments showed bladesin hydrogels can accelerate cutaneous wound healing. The mechanism exploration revealed that it can promote pathogen clearance, enhance collagen deposition and regulate inflammatory responses. These findings suggested that this bladesin-based dressings represented a promising therapeutic strategy for the treatment of infected wounds.