Abstract
Macrophage metabolism dysregulation, which is exacerbated by persistent stimulation in infectious and inflammatory diseases, such as diabetic infectious bone defects (DIBD), eventually leads to the failure of bone repair. Here, we have developed an injectable, macrophage-modulated GAPDH-Silence drug delivery system. This microsphere comprises chondroitin sulfate methacrylate (CM) and methacrylated gelatin (GM), while the dimethyl fumarate (DMF)-loaded liposome (D-lip) is encapsulated within the microsphere (CM@GM), named D-lip/CM@GM. Triggered by the over-expressed collagenase in DIBD, the microspheres degrade and release the encapsulated D-lip. D-lip could modulate metabolism by inhibiting GAPDH, which suppresses the over-activation of glycolysis, thus preventing the inflammatory response of macrophages in vitro. While beneficial for macrophages, D-lip/CM@GM is harmful to bacteria. GAPDH, while crucial for glycolysis of staphylococcal species (S. aureus), can be effectively countered by D-lip/CM@GM. We are utilizing existing drugs in innovative ways to target central metabolism for effective eradication of bacteria. In the DIBD model, our results confirmed that the D-lip/CM@GM enhanced bacteria clearance and reprogrammed dysregulated metabolism, thereby significantly improving bone regeneration. In conclusion, this GAPDH-Silence microsphere system may provide a viable strategy to promote diabetic infection bone regeneration.