A H2S-releasing oridonin derivative improves diabetic wound healing based on antibacterial activity and regulation of macrophage phagocytosis

H 2 S-releasing oridonin derivative promotes wound healing in diabetic mice. • H 2 S-releasing oridonin derivative inhibits S. aureus and MRSA growth and biofilm formation. • H 2 S-releasing oridonin derivative upregulates TLR2 expression and autophagy-mediated phagocytosis of S. aureus . Chronic diabetic wounds are characterized by persistent bacterial burden and impaired healing. Oridonin, a natural diterpenoid, shows potential for wound repair but is limited by poor solubility and bioavailability. A promising strategy to enhance oridonin's efficacy involves its conjugation with H 2 S donors. In our study, a type 1 diabetic mouse wound model was treated topically with hydrogels containing oridonin, α-thioctic acid, or H 2 S-releasing oridonin derivative D5 for 14 days. D5 treatment induced epithelial thickening, collagen deposition, and upregulation of Ki67 and CD31, as evidenced by histological and immunofluorescence analyses. Blood agar assays confirmed D5 reduced wound bacterial colonization. In vitro, D5 inhibited the growth and biofilm formation of Staphylococcus aureus and methicillin-resistant S. aureus , and disrupted preformed biofilms. Moreover, D5 dose-dependently enhanced RAW264.7 phagocytosis of S. aureus . Mechanistically, it upregulated TLR2 and MyD88 protein expression and activated PI3K/AKT/mTOR-mediated autophagy, while the effects were abolished by TLR2 siRNA transfection, the TLR2 inhibitor C29, and the autophagy inhibitor 3-MA. Molecular docking, molecular dynamics, and thermal shift assays supported a potential interaction between D5 and TLR2. In addition, D5 treatment was associated with increased TLR2 protein stability, potentially involving proteasome-related regulation. Collectively, these findings suggest that D5 promotes diabetic wound healing by reducing bacterial burden and enhancing TLR2-dependent autophagy-mediated phagocytosis, providing a promising therapeutic strategy for diabetic wound repair. Download: Download high-res image (88KB) Download: Download full-size image