DNA tetrahedron-mediated vascular targeted delivery of astragaloside IV enhances distraction osteogenesis via PI3K/AKT/FOXO pathway.

Abstract

Bone regeneration during distraction osteogenesis (DO) remains limited by insufficient vascularization, which delays consolidation and compromises clinical outcomes. Here, we developed a vascular-targeted DNA nanoplatform (TDN@Ast-AptCD34) for the delivery of Astragaloside IV (Ast), a natural compound with pro-angiogenic and osteogenic properties. The nanoplatform integrated a DNA tetrahedron carrier with a vascular-targeting aptamer (AptCD34) and was further incorporated into a biocompatible mHA-PVA hydrogel for localized and sustained release. Physicochemical analyses confirmed its stable structure, efficient Ast encapsulation, and enhanced uptake by endothelial progenitor cells (EPCs). Functionally, TDN@Ast-AptCD34 significantly promoted EPC migration, tube formation, and paracrine-mediated osteogenesis of jaw bone mesenchymal stem cells (JBMSCs), thereby reinforcing angiogenesis-osteogenesis coupling. Integrated network pharmacology, RNA sequencing, and molecular dynamics simulations identified PI3K/AKT/FOXO signaling as the central downstream axis. Mechanistically, TDN@Ast-AptCD34 activated PI3K/AKT signaling and relieved FOXO1-mediated repression of angiogenic genes, which was validated by rescue experiments under PI3K inhibition. In vivo, the hydrogel-delivered nanoplatform markedly enhanced early vascularization and robust bone regeneration in a mandibular DO model, whereas these effects were significantly attenuated upon PI3K inhibition by LY294002. Collectively, this study establishes TDN@Ast-AptCD34 as a multifunctional nanoplatform that couples angiogenesis with osteogenesis via PI3K/AKT/FOXO signaling, providing a promising strategy for vascularized bone regeneration in challenging clinical settings.