Sea buckthorn-derived extracellular vesicles foster bone regeneration through aau-miR168-mediated pathways.

BACKGROUND

Plant-derived extracellular vesicles (P-EVs) possess remarkable therapeutic potential, yet the regenerative capabilities of sea buckthorn-derived extracellular vesicles (SAEVs) remain underexplored. This study aims to elucidate the osteogenic and bone-healing properties of SAEVs.

METHODS

SAEVs were isolated from sea buckthorn juice via differential centrifugation and characterized using electron microscopy and dynamic light scattering. Bone marrow mesenchymal stromal cells (BMSCs) were treated with SAEVs, and cellular uptake was evaluated through fluorescence microscopy and flow cytometry. In vivo, DiD-labeled SAEVs were orally administered to mice to determine biodistribution using IVIS imaging. A murine femoral defect model was employed to assess the bone regenerative efficacy of SAEVs delivered with or without GelMA hydrogels, analyzed by micro-CT and histological staining. Small RNA sequencing identified SAEV-derived miRNAs, and luciferase reporter assays validated the miRNA-mediated regulation of osteogenic genes.

RESULTS

SAEVs efficiently internalized into BMSCs via macropinocytosis, promoting the expression of key osteogenic markers such as Runx2 and osteocalcin. In vivo, SAEV-GelMA hydrogels significantly accelerated bone regeneration in a femoral defect model without inducing adverse hematological effects, affirming the safety of SAEV administration. Mechanistic investigations revealed an enrichment of miRNAs, particularly aau-miR168, which modulates osteogenesis through the aau-miR168/LBH/RUNX2 signaling cascade.

CONCLUSIONS

This study highlights SAEVs as a transformative and biocompatible therapeutic strategy for fracture healing and osteoporosis management, offering a novel avenue for regenerative medicine.