Co-transfection with the osteogenic protein (OP)-1 gene and the insulin-like growth factor (IGF)-I gene enhanced osteoblastic cell differentiation.
Previous studies from this laboratory showed that the action of Osteogenic Protein-1 (OP-1, BMP-7) on osteoblastic cell differentiation could be enhanced by other protein factors, such as Insulin-like Growth Factor (IGF)-I. In the present study, we examined the effects of co-transfection with a combination of the OP-1 and the IGF-I gene on osteoblastic cell differentiation. The results first showed that fetal rat calvaria (FRC) cells transfected with the OP-1 gene under the control of the cytomegalovirus (CMV) promoter showed substantial production of the OP-1 protein. Transfected FRC cells also showed a DNA concentration-dependent increase in alkaline phosphatase (AP) activity, an osteoblastic cell differentiation marker. Von Kossa-positive nodules, a hallmark of bone formation in long-term cultures of bone-derived cells, were also observed in the transfected cells after 26 days in culture, whereas none were observed in control cells. Co-transfection of FRC cells with the combination of the OP-1 and the IGF-I gene resulted in a synergistic stimulation of AP activity. The increase was DNA dose-dependent. The current data show that transfection of OP-1 gene into osteoblastic cells stimulates osteoblastic cell differentiation in vitro. The study further demonstrates the feasibility of employing gene transfer of a second gene in combination with an OP-1 vector to synergistically enhance OP-1 activity.
Yeh
Lee-Chuan C
LC
Department of Biochemistry, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, USA. yeh1@uthscsa.edu
Lee
John C
JC
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000235:genetics* / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D005260:Female; D007334:Insulin-Like Growth Factor I / Q000235:genetics* / Q000378:metabolism*; D010006:Osteoblasts / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012886:Skull / Q000166:cytology / Q000187:drug effects; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism*
C525821:Bmp7 protein, rat; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta; D007334:Insulin-Like Growth Factor I; D000469:Alkaline Phosphatase