Pilose antler peptide enhances diabetic fracture healing by modulating the CREB-Smad2/3-Runx2 signaling axis

Cervi Cornu Pantotrichum, a cornerstone of traditional medicine, is prized for its bone-enhancing and metabolic-regulating effects. Pilose antler peptide (PAP), extracted from this remedy, offers a promising solution for diabetic fracture nonunion, a debilitating condition marked by hyperglycemia-impaired bone healing.

This study investigates PAP's efficacy in accelerating diabetic fracture repair and delineates its molecular mechanisms, merging ethnopharmacological heritage with modern science.

Diabetic fractures were induced in db/db mice, and PAP's effects were evaluated using micro-CT, histology, and osteogenic marker analysis. In vitro, high glucose-treated MC3T3-E1 osteoblasts mimicked diabetic conditions. Molecular mechanisms were probed via co-immunoprecipitation (Co-IP), fluorescence colocalization, molecular docking, and genetic modulation.

PAP markedly improved fracture healing in diabetic mice, enhancing callus integrity, bone microarchitecture, and osteogenic marker levels. In osteoblasts, PAP counteracted high glucose-induced osteogenic suppression, boosting Runx2 expression while inhibiting CREB and Smad3 activation. Co-IP revealed PAP's disruption of the CREB-Smad2/3 complex, with colocalization showing diminished nuclear overlap of CREB and Smad2/3. Molecular docking identified PAP binding to CREB-Arg117 and Smad3-Glu246, supporting its inhibitory role. Genetic studies confirmed PAP's reversal of Smad2/3-mediated Runx2 suppression.

PAP alleviates metabolic stress and promotes bone regeneration by targeting the CREB-Smad2/3-Runx2 axis. Rooted in ethnopharmacology, this multitarget peptide integrates traditional wisdom with cutting-edge molecular insights, presenting a novel therapeutic avenue for diabetic fracture management.