Combinatorial Therapy of LL-37 and ADSCs Accelerates Diabetic Wound Repair by Orchestrating NRROS-mediated Crosstalk Between TGF-β/SMAD and Hippo/tead1 Axes

Diabetic wounds pose a significant therapeutic challenge. While the antimicrobial peptide LL-37 and adipose-derived stem cells (ADSCs) individually show potential for wound repair, the efficacy and mechanism of their combined treatment remain unclear. This study aimed to investigate the therapeutic effect of LL-37 combined with ADSCs on diabetic wound healing. Clinical samples from diabetic and non-diabetic patients were analyzed, combined with bioinformatics analysis of public datasets (GSE144441 and GSE182906) to identify key genes. A diabetic mouse wound model was established to validate the healing effects of individual and combined LL-37 and ADSCs treatments. In vitro assays, co-culture models were employed to explore the mechanisms involving ADSCs and fibroblasts. Analysis of human diabetic wounds revealed impaired healing associated with deficiency in cathelicidin antimicrobial peptide (CAMP), the precursor of LL-37. In diabetic mice, the combination of LL-37 and ADSCs promoted wound healing more effectively than either treatment alone. LL-37 enhanced ADSC viability in a dose-dependent manner. Mechanistically, LL-37 treatment significantly upregulated the expression of negative regulator of reactive oxygen species (NRROS) in ADSCs. Exosomes derived from these LL-37-primed ADSCs were taken up by fibroblasts, leading to increased NRROS expression in the recipient fibroblasts. Upregulated NRROS subsequently activated both the TGF-β/SMAD and Hippo/TEAD1 signaling pathways. Further experiments confirmed crosstalk between these two pathways, which collectively enhanced fibroblast proliferation and migration. In conclusion, the combination of LL-37 and ADSCs promotes diabetic wound healing by enhancing fibroblast activity. This effect is mediated through exosomal transfer of NRROS from ADSCs to fibroblasts, leading to the activation of the interconnected TGF-β/SMAD and Hippo/TEAD1 signaling pathways.