Temporin-GHa11R accelerates MRSA-infected wound healing via antibacterial efficacy and regulation of macrophage polarization

The dynamic balance of macrophage polarization is critical for the process of wound repair, whereas bacterial infection can provoke an excessive inflammatory response, consequently delaying wound healing. In this study, we demonstrated that temporin-GHa11R (GHa11R), a temporin-derived peptide, exhibited potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA, MIC = 3.1 μM) and strong antibiofilm capacity, as indicated by its low minimum biofilm inhibitory and eradication concentrations (MBIC 50 = 1.8 μM and MBEC 50 = 5.2 μM), along with a low propensity to induce drug resistance. GHa11R can adsorb onto the membrane, cause depolarization, and penetrate into the cytoplasm, indicating a non-lytic mechanism. In vitro analyses demonstrated that GHa11R significantly inhibited lipopolysaccharide (LPS)-induced M1 polarization in RAW264.7 macrophages by suppressing the overactivation of the NF-κB/MAPK signaling pathways, thereby exerting anti-inflammatory effects. Concurrently, GHa11R acted synergistically with interleukin-4 (IL-4) to promote macrophage polarization toward the M2 phenotype. Furthermore, GHa11R enhanced the migration of keratinocytes (HaCaT) and endothelial cells (HUVECs), and promoted angiogenesis. In a mouse model of MRSA-infected wounds, topical application of GHa11R significantly reduced the local bacterial burden, alleviated the inflammatory response, and regulated the macrophage polarization from M1 to M2 phenotype. GHa11R treatment also facilitated wound re-epithelialization, granulation tissue formation, orderly collagen deposition, and neovascularization. Our results indicate that GHa11R exerts multiple biological functions, including antibacterial, immunomodulatory, and pro-repair activities, thereby effectively promoting the healing of infected wounds. This study lays a foundation for the application of temporin-derived peptides in the management of chronic infectious wounds.