Osteoinduction by repeat plasmid injection of human bone morphogenetic protein-2.
BACKGROUND
Bone morphogenetic protein-2 (BMP-2) is an osteoinductive protein and is considered useful for the treatment of skeletal disorders. Previous studies using BMP-2 in clinical applications have encountered difficulties, including the lack of an efficient, safe, inexpensive and simple delivery system. The gene transfer approach is a promising option for utilizing BMP-2. Although viral vector-mediated gene transfer is efficient, safety concerns prevent its clinical application for common diseases. On the other hand, plasmid-based gene transfer is a safe method and can be harnessed for practical applications.


METHODS
A plasmid encoding human BMP-2 (pCAGGS-BMP-2) was used and injected repeatedly (one to eight times) into the skeletal muscle of mice at a divided dose. We compared the capability of osteoinduction in the skeletal muscle of mice after gene transfer by repeat injection. BMP-2 production was assessed via immunohistochemistry, and osteoinduction was evaluated using radiography, histology and biochemical assays.


RESULTS
The BMP-2 gene was transferred into the skeletal muscle of mice by repeat injection using pCAGGS-BMP-2. Mature bone was frequently observed in mice injected repeatedly with pCAGGS-BMP-2 at a divided dose. This confirms that, if the total dose is fixed, repeat injection with pCAGGS-BMP-2 at a divided dose causes osteoinduction more frequently in the skeletal muscle of mice.


CONCLUSIONS
These results suggest the possibility of the effective clinical use of human BMP-2 gene therapy by direct DNA injection, and facilitate the clinical application of BMP-2 gene therapy.
Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan. kosawa@kuhp.kyoto-u.ac.jp
Kenji
K
Osawa
Yasunori
Y
Okubo
Kazumasa
K
Nakao
Noriaki
N
Koyama
Kazuhisa
K
Bessho
D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics*; D006801:Humans; D051379:Mice; D018482:Muscle, Skeletal; D010012:Osteogenesis / Q000187:drug effects*; D010957:Plasmids
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2