Isolation and characterization of posterofrontal/sagittal suture mesenchymal cells in vitro.
BACKGROUND
Craniosynostosis, the premature fusion of cranial sutures, affects one in 2500 children. In the mouse, the posterofrontal suture is programed to fuse postnatally, but the adjacent sagittal suture remains patent throughout life. To study the cellular process of suture fusion, the authors isolated and studied suture-derived mesenchymal cells.


METHODS
Skulls were harvested from 80 mice (2 to 5 days old), and posterofrontal and sagittal sutures were dissected meticulously. Suture mesenchymal tissue was separated from the underlying dura mater and overlying pericranium and cultured in growth media. After the cells migrated from the explant tissues, the morphologies of the two cell populations were studied carefully, and quantitative real-time polymerase chain reaction was performed to evaluate gene expression.


RESULTS
Both posterofrontal and sagittal cells exhibited highly heterogeneous morphologies, and the posterofrontal cells migrated faster than the sagittal cells. Accordingly, growth factors such as transforming growth factor-beta1 and fibroblast growth factor (FGF)-2 were expressed significantly more highly in posterofrontal compared with sagittal suture mesenchymal cells. In contrast, FGF receptor 2 and FGF-18 were expressed significantly more in sagittal than in posterofrontal suture cells. Importantly, bone morphogenic protein-3, the only osteogenic inhibitor in the bone morphogenic protein family, and noggin, a bone morphogenic protein antagonist, were expressed significantly more in sagittal than in posterofrontal suture cells, suggesting a possible mechanism of suture patency.


CONCLUSIONS
To the authors' knowledge, this is the first analysis of mouse suture-derived mesenchymal cells. The authors conclude that isolation of suture-derived mesenchymal cells will provide a useful in vitro system with which to study the mechanisms underlying suture biology.
Xu
Yue
Y
Children's Surgical Research Program and Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA.
Malladi
Preeti
P
Chiou
Michael
M
Longaker
Michael T
MT
D000818:Animals; D055398:Bone Morphogenetic Protein 3; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002465:Cell Movement; D002478:Cells, Cultured; D020219:Chondrogenesis; D003393:Cranial Sutures / Q000166:cytology*; D003398:Craniosynostoses / Q000473:pathology / Q000503:physiopathology; D004388:Dura Mater / Q000166:cytology / Q000502:physiology; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism; D015870:Gene Expression; D007150:Immunohistochemistry; D008648:Mesoderm / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D010012:Osteogenesis; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D051497:Receptor, Fibroblast Growth Factor, Type 2 / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D000099176:Noggin Protein
D055398:Bone Morphogenetic Protein 3; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D016222:Fibroblast Growth Factor 2; D005346:Fibroblast Growth Factors; D012333:RNA, Messenger; D051497:Receptor, Fibroblast Growth Factor, Type 2; D053773:Transforming Growth Factor beta1; D000099176:Noggin Protein; C113569:fibroblast growth factor 18