Synthetic biology‐based bacterial extracellular vesicles displaying BMP‐2 and CXCR4 to ameliorate osteoporosis

Abstract Osteoporosis (OP) is a systematic bone disease characterized by low bone mass and fragile bone microarchitecture. Conventional treatment for OP has limited efficacy and long‐term toxicity. Synthetic biology makes bacterial extracellular vesicle (BEVs)‐based therapeutic strategies a promising alternative for the treatment of OP. Here, we constructed a recombinant probiotics Escherichia coli Nissle 1917‐pET28a‐ClyA‐BMP‐2‐CXCR4 (ECN‐pClyA‐BMP‐2‐CXCR4), in which BMP‐2 and CXCR4 were overexpressed in fusion with BEVs surface protein ClyA. Subsequently, we isolated engineered BEVs‐BMP‐2‐CXCR4 (BEVs‐BC) for OP therapy. The engineered BEVs‐BC exhibited great bone targeting in vivo. In addition, BEVs‐BC had good biocompatibility and remarkable ability to promote osteogenic differentiation of BMSCs. Finally, the synthetic biology‐based BEVs‐BC significantly prevented the OP in an ovariectomized (OVX) mouse model. In conclusion, we constructed BEVs‐BC with both bone‐targeting and bone‐forming in one‐step using synthetic biology, which provides an effective strategy for OP and has great potential for industrialization.