Hydrogel armed with Bmp2 mRNA-enriched exosomes enhances bone regeneration

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Molecular Biology

Background:

• Sustained release of bone morphogenetic protein-2 (BMP2) is crucial for bone regeneration.
• The short in vivo half-life of BMP2 protein limits its clinical efficacy.
• Developing strategies for sustained BMP2 delivery is essential for effective bone repair.

Purpose of the Study:

• To design Bmp2 mRNA-enriched exosomes for sustained BMP2 delivery.
• To load these engineered exosomes into a hydrogel for controlled release.
• To evaluate the efficacy of this system in promoting bone regeneration.

Main Methods:

• Engineered exosomes (Exo^BMP2+NoBody) were created by co-transfecting donor cells with BMP2 plasmids and NoBody (non-annotated P-body dissociating polypeptide) to inhibit translation and enrich Bmp2 mRNA.
• Exosomes were loaded into GelMA hydrogel using an ally-L-glycine modified CP05 linker for sustained release.
• The system's bone regeneration capacity was assessed using an in vivo calvarial defect model.

Main Results:

• Exo^BMP2+NoBody exhibited higher Bmp2 mRNA abundance and enhanced osteogenic induction capacity in vitro.
• Loading into GelMA hydrogel facilitated slow release of exosomes, ensuring prolonged BMP2 effect upon cellular uptake.
• Exo^BMP2+NoBody-loaded GelMA significantly promoted bone regeneration in the in vivo calvarial defect model.

Conclusions:

• The developed Exo^BMP2+NoBody-loaded GelMA hydrogel represents an efficient strategy for bone regeneration.
• This approach offers a novel method for sustained delivery of therapeutic mRNA.
• The system demonstrates potential for improved and safer bone regeneration therapies.