Antiosteoporosis gene-based drug development strategies are presently focused on targeting osteoblasts to either suppress bone loss or increase bone mass. Although siRNA/microRNA-based gene therapy has enormous potential, it is severely limited by the lack of specific cell-targeting delivery systems. We report an osteoblast-targeting peptide (SDSSD) that selectively binds to osteoblasts via periostin. We developed SDSSD-modified polyurethane (PU) nanomicelles encapsulating siRNA/microRNA that delivers drugs to osteoblasts; the data showed that SDSSD-PU could selectively target not only bone-formation surfaces but also osteoblasts without overt toxicity or eliciting an immune response in vivo. We used the SDSSD-PU delivery system to deliver anti-miR-214 to osteoblasts and our results showed increased bone formation, improved bone microarchitecture, and increased bone mass in an ovariectomized osteoporosis mouse model. SDSSD-PU may be a useful osteoblast-targeting small nucleic acid delivery system that could be used as an anabolic strategy to treat osteoblast-induced bone diseases.
Keywords: bone formation; gene delivery; osteoblast targeting peptide; osteoporosis therapy; polyurethane nanoparticle.