Bone morphogenetic protein-7 enhances cementoblast function in vitro.
BACKGROUND
Bone morphogenetic protein (BMP)-7 is a potent bone-inducing factor and was shown to promote periodontal regeneration in vivo and in vitro; however, to our knowledge, the specific effect of BMP-7 on cementoblasts has not been defined. We aimed to investigate the effects of BMP-7 on cementoblasts, which are cells responsible for tooth root-cementum formation. We hypothesized that BMP-7 would regulate mineralized tissue-associated genes in cementoblasts and influence the expression profile of genes associated with cementoblast extracellular matrix (ECM) and cell adhesion molecules (CAMs).


METHODS
A murine immortalized cementoblast cell line (OCCM.30) was cultured with and without 50 ng/ml BMP-7. After 72 hours, total RNA was isolated, and mRNA levels for bone/cementum markers, including bone sialoprotein (BSP), osteocalcin (OCN), osteopontin (OPN), and runt-related transcription factor-2 (Runx2), were investigated by real-time quantitative reverse transcription-polymerase chain reaction (Q-PCR). In vitro mineral nodule formation was assayed on day 8 using von Kossa staining. A pathway-specific gene-expression array was used to determine BMP-7-responsive ECM and CAM genes in cementoblasts.


RESULTS
Mineralized tissue markers were strongly regulated by BMP-7, with an almost three-fold increase in BSP and OCN transcripts and significant increases in OPN and Runx2 mRNA expressions. BMP-7 treatment markedly stimulated cementoblast-mediated biomineralization in vitro compared to untreated cells at day 8. BMP-7 treatment altered the OCCM.30 expression profile for ECM and CAM functional gene groups. BMP-7 tended to increase the expression of collagens and matrix metalloproteinases (MMPs), mildly decreased tissue inhibitors of MMPs (TIMPs), and had mixed regulatory effects on integrins. Using Q-PCR, selected array results were confirmed, including a significant BMP-7-induced increase in MMP-3 and a decrease in TIMP-2 mRNA expression.


CONCLUSIONS
These results support the promising applications of BMP-7 in therapies aimed at regenerating periodontal tissues lost as a consequence of disease.
Hakki
Sema S
SS
Department of Periodontology, Faculty of Dentistry, Selcuk University, Konya, Turkey. sshakki@yahoo.com
Foster
Brian L
BL
Nagatomo
Kanako J
KJ
Bozkurt
S Buket
SB
Hakki
Erdogan E
EE
Somerman
Martha J
MJ
Nohutcu
Rahime M
RM
D000818:Animals; D055419:Bone Morphogenetic Protein 7 / Q000494:pharmacology*; D002113:Calcification, Physiologic / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D003094:Collagen / Q000187:drug effects; D050659:Core Binding Factor Alpha 1 Subunit / Q000187:drug effects; D003739:Dental Cementum / Q000166:cytology / Q000187:drug effects*; D016326:Extracellular Matrix Proteins / Q000187:drug effects; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D016023:Integrins / Q000187:drug effects; D019278:Matrix Metalloproteinase 3 / Q000187:drug effects; D020782:Matrix Metalloproteinases / Q000187:drug effects; D051379:Mice; D015675:Osteocalcin / Q000187:drug effects; D053495:Osteopontin / Q000187:drug effects; D040081:Protein Array Analysis; D013997:Time Factors; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000187:drug effects; D019714:Tissue Inhibitor of Metalloproteinases / Q000187:drug effects; D014092:Tooth Root / Q000166:cytology / Q000187:drug effects; D015854:Up-Regulation
D055419:Bone Morphogenetic Protein 7; D015815:Cell Adhesion Molecules; D050659:Core Binding Factor Alpha 1 Subunit; D016326:Extracellular Matrix Proteins; D016023:Integrins; C493716:Runx2 protein, mouse; C506896:Spp1 protein, mouse; D019714:Tissue Inhibitor of Metalloproteinases; C525820:bmp7 protein, mouse; D015675:Osteocalcin; D053495:Osteopontin; D019716:Tissue Inhibitor of Metalloproteinase-2; D003094:Collagen; D020782:Matrix Metalloproteinases; D019278:Matrix Metalloproteinase 3; C511769:Mmp3 protein, mouse