title: Platelet-derived growth factor exerts disparate effects on odontoblast differentiation depending on the dimers in rat dental pulp cells.
abstract: Platelet-derived growth factor (PDGF) has recently been demonstrated to control the expression of alkaline phosphatase and proteoglycan synthesis of odontoblastic cells in dental pulp tissues. Although PDGF appears to be closely related to dentinogenesis, much about the mode of action of PDGF on odontoblast differentiation remains unclear. In this study, we examined the effects of three PDGF dimers (PDGF AA, AB, and BB) on odontoblastic differentiation of dental pulp cells in long-term mineralized cultures. Dental pulp cells isolated from rat lower incisors were continuously treated with each of PDGF AA, AB, and BB in separate cultures for 20 days. The three PDGF dimers suppressed alkaline phosphatase activity, osteocalcin and calcium content, and the formation of dentin-like nodules. The expression of mRNA for dentin sialoprotein (DSP) in the cells was inhibited by PDGF AA treatment, whereas PDGF AB and BB treatment stimulated the expression of DSP, even though the dentin-like nodule formation was inhibited. Although the effects of PDGF on odontoblastic differentiation varied among the dimers, the cells expressed both PDGF alpha and beta receptors, whose quantities were similar. These results suggest that PDGF exerts diverse effects on odontoblastic differentiation depending on its dimeric form. These in vitro findings explain, at least in part, the in vivo action of PDGF in dentinogenesis during the repair process of damaged dental pulp.
authors.affiliation: Department of Operative Dentistry, School of Dentistry, Meikai University, 1-1 Keyakidai, Sakado, 350-0283 Saitama, Japan. yokose@ra2.so-net.ne.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yokose
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kadokura
authors.forename: Naoto
authors.initials: N
authors.lastname: Tajima
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hasegawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakagami
authors.forename: Kazuo
authors.initials: K
authors.lastname: Fujieda
authors.forename: Tadashi
authors.initials: T
authors.lastname: Katayama
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D003782:Dental Pulp / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D003784:Dental Pulp Calcification; D003804:Dentin / Q000187:drug effects / Q000378:metabolism; D019281:Dimerization; D016326:Extracellular Matrix Proteins; D005260:Female; D006801:Humans; D007180:Incisor; D008222:Lymphokines / Q000737:chemistry / Q000494:pharmacology*; D009804:Odontoblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D015675:Osteocalcin / Q000378:metabolism; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor / Q000737:chemistry / Q000494:pharmacology*; D011498:Protein Precursors; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism; D012795:Sialoglycoproteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D000099311:Dentin Sialophosphoprotein
chemical_list: D000469:Alkaline Phosphatase; D002118:Calcium; D016326:Extracellular Matrix Proteins; D008222:Lymphokines; D015675:Osteocalcin; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D011498:Protein Precursors; D012333:RNA, Messenger; D017479:Receptors, Platelet-Derived Growth Factor; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C427493:PDGFD protein, human; C498952:Pdgfd protein, rat