Confocal laser microscopy of chondrocytes that received gene transfer using in vitro electroporation

To develop a gene therapy for osteopathies, this study was conducted to establish a method of transferring the BMP gene, a bone formation factor, to cells and administering the cells with BMP expression to patients with osteopathies. Although virus vectors are frequently used for gene transfer, there has been reported a death case of gene therapy using the adenovirus vector. Therefore, various efforts have been made to prevent such complications. In the present study, we used electroporation by which gene transfer can be efficiently performed without inducing severe complications after electric perforation of the cell membrane. Human bone tissues were initially collected intraoperatively, and BMP-2 and Smad4 genes were cloned and integrated into GFP and DsRed plasmid vectors. Using in vitro electroporation, these plasmid vectors were transferred to the cultured chondrocytes (KTN-1) derived from human herniated intervertebral disk. Confocal laser microscopy revealed that the BMP gene was successfully transferred to the nucleus of chondrocytes in the presence of Smad. Since electroporation facilitated human gene transfer to the target cells, gene therapy using electroporation may facilitate individualized treatment for patients.