FGF21-modified adipose stem cell-derived exosomes promote wound healing by activating fibroblast glycolysis through AMPK/mTOR signaling.

Chronic wound healing disorders remain a significant clinical challenge, largely due to the limited effectiveness of conventional therapeutic strategies. Emerging evidence suggests that engineered exosomes represent a promising cell-free therapeutic approach. This study aimed to elucidate the mechanisms by which fibroblast growth factor 21 (FGF21)-modified adipose-derived mesenchymal stem cell (ADSC) exosomes promote wound healing. ADSCs overexpressing FGF21 were established using genetic engineering, and FGF21-enriched exosomes (Exo@FGF21) were isolated and characterized using transmission electron microscopy and nanoparticle tracking analysis. The biological effects of Exo@FGF21 on human skin fibroblasts (HSFs) were assessed through proliferation, migration, invasion, and apoptosis assays. Glycolytic activity, glucose consumption, lactate production, ATP levels, and hydroxyproline content were evaluated to investigate metabolic changes. Mechanistic studies involved pharmacological inhibition of AMPK and knockdown of PFKFB3. Therapeutic efficacy was further examined in a mouse full-thickness skin defect model. Exo@FGF21 exhibited typical exosomal morphology with diameters ranging from 80 to 150 nm and expressed canonical exosomal markers CD9 and CD63. In vitro, Exo@FGF21 significantly enhanced fibroblast proliferation, migration, and invasion, promoted collagen synthesis-related gene expression (COL1A1, COL3A1, FN1), and reduced apoptosis. Mechanistically, Exo@FGF21 activated AMPK, suppressed mTOR signaling, and upregulated PFKFB3 expression. Both AMPK inhibition and PFKFB3 knockdown markedly attenuated these pro-repair effects. Metabolic analyses demonstrated enhanced glycolysis, increased glucose utilization, elevated lactate production, and augmented ATP and hydroxyproline levels, indicating glycolytic metabolic reprogramming. In vivo, Exo@FGF21 accelerated wound closure, promoted epidermal regeneration, enhanced collagen deposition, and activated the AMPK/mTOR/PFKFB3 pathway. FGF21-modified ADSC-derived exosomes promote wound healing by inducing fibroblast glycolytic metabolic reprogramming via the AMPK/mTOR/PFKFB3 signaling axis. These findings provide novel mechanistic insights and support the therapeutic potential of engineered exosome-based strategies for chronic wound repair.