Expression and possible mechanisms of regulation of BMP3 in rat cranial sutures.
BACKGROUND
Clinical genetics data and investigative studies have contributed greatly to our understanding of the role of numerous genes in craniosynostosis. Recent studies have introduced antagonists of osteogenesis as potential key regulators of suture fusion and patency. The authors investigated the expression pattern of the bone morphogenetic protein antagonist BMP3 in rat cranial sutures and the factors regulating its expression in vitro.


METHODS
Microarray analysis was performed on rat posterior frontal and sagittal cranial sutures at 5, 10, 15, 20, and 30 days of life (n = 30 per group). Gene expression was confirmed using quantitative real-time reverse transcriptase polymerase chain reaction. Regulation of BMP3 expression was determined using primary rat calvarial osteoblasts stimulated with recombinant human fibroblast growth factor 2 or recombinant human transforming growth factor beta1, or cultured with primary rat nonsuture dura mater. Gene expression was quantified with quantitative real-time reverse transcriptase polymerase chain reaction.


RESULTS
BMP3 expression in the posterior frontal suture decreased over the time course analyzed, whereas it increased in the sagittal suture. Notably, BMP3 expression was higher in the patent sagittal suture during the window of posterior frontal suture fusion. Stimulation of osteoblasts with recombinant human fibroblast growth factor 2 led to a rapid and sustained suppression of BMP3 expression (85 percent, p < 0.01) when compared with controls. Co-culture with dural cells decreased BMP3 mRNA by 50 percent compared with controls (p < 0.01).


CONCLUSIONS
BMP3 is expressed in rat cranial sutures in a temporal pattern suggesting involvement in cranial suture patency and fusion. Furthermore, BMP3 is regulated in calvarial osteoblasts by recombinant human fibroblast growth factor 2 and by paracrine signaling from dura mater. These data add to our knowledge of the role of osteogenic antagonists in cranial suture biology.
Nacamuli
Randall P
RP
Department of Surgery, Stanford University School of Medicine, Stanford, California 94305-5148, USA.
Fong
Kenton D
KD
Lenton
Kelly A
KA
Song
HanJoon M
HM
Fang
Tony D
TD
Salim
Ali
A
Longaker
Michael T
MT
D000818:Animals; D055398:Bone Morphogenetic Protein 3; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002352:Carrier Proteins; D002478:Cells, Cultured; D018920:Coculture Techniques; D003393:Cranial Sutures / Q000378:metabolism*; D015536:Down-Regulation / Q000502:physiology; D004388:Dura Mater / Q000166:cytology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D000099176:Noggin Protein
D055398:Bone Morphogenetic Protein 3; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D016222:Fibroblast Growth Factor 2; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D000099176:Noggin Protein; C525757:BMP3 protein, human; C525759:Bmp3 protein, rat; C508960:TGFB1 protein, human; C508962:Tgfb1 protein, rat