Osaka Dental University, Japan
Mariko Kawai is Doctor of Dental Surgery. She has completed her PhD from Kyoto University, Medical School. She is working as an Assistant Professor at Okayama University and Osaka Dental University, Japan. She is mainly conducts her research in Electroporation technique for gene transfer. She carries her research in simple and efficient gene therapy bone regeneration.
It is well known that bone morphogenetic protein (BMP) has strong osteogenic ability when the recombinant protein or BMP gene is transferred into the skeletal muscle. We previously tried to transfer BMP gene to the target site using adenoviral vector. But, we needed general or local immunosuppression to induce bone formation. The adenoviral vectors stimulate immuno-response and prevent bone induction. Therefore, we developed a novel method for BMP gene transfer, which is non-viral BMP gene expression vector and transcutaneous in vivo electroporation. First, we applied this method to transfer BMP-2 gene and induced ectopic bone formation in the skeletal muscle. We injected BMP gene expression vector, pCAGGS-BMP-2, in the skeletal muscles of rats and immediately electroporated under conditions 100V, 50 msec, and 8 pulses. We found ectopic bone formation in the skeletal muscles 21 days after BMP gene transfer. In the BMP family, BMP-2/4 or BMP-2/7 heterodimer has stronger potential for bone induction compared with BMP-2, BMP-4 or BMP-7 homodimer. Then, we constructed BMP-2/7 heterodimer produced vector: pCAGGS-BMP-2/7. It has no IRES site and BMP-2 and BMP-7 expression are equal. The procedure of pCAGGS-BMP-2/7 and in vivo electroporation induced ectopic bone formation quickly on 10 days after gene transfer. For clinical application, we need lower voltage condition than 100 V. If we set the condition: 50 voltage and 8 pulses, the efficiency of gene transfer also reduced. But, when we induced pulse number, it recovered. We evaluated proper voltage and pulse number as the same gene transfer efficiency of 100V. Now, we tried to apply this gene transfer system for alveolar bone regeneration under the condition with 50V, 50 msec, 32 pulses. We often used bone prosthetic material and autogenous bone for alveolar bone defect caused by periodontal disease or oral tumor. Gene therapy for bone regeneration will be with more safety and with fewer burdens on the patient.