title: Parathyroid hormone (1-34) modulates odontoblast proliferation and apoptosis via PKA and PKC-dependent pathways.
abstract: Parathyroid hormone (PTH) plays a key role in the development and homeostasis of mineralized tissues such as bone and dentine. We have reported that PTH (1-34) administration can increase dentine formation in mice and that this hormone modulates in vitro mineralization of odontoblast-like cells. The purpose of the present study was to investigate whether PTH (1-34) participates in the proliferative and apoptotic signaling of odontoblast-like cells (MDPC23). MDPC23 cells were exposed to 50 ng/ml hPTH (1-34) or vehicle for 1 (P1), 24 (P24), or 48 (P48) hours, and the cell proliferation, apoptosis, and cell number were evaluated. To examine whether changes in the proliferative and apoptotic signaling in response to PTH involve protein kinases A (PKA) and/or C (PKC), MDPC23 cells were exposed to PTH with or without PKC or PKA signaling pathway inhibitors. Overall, the results showed that the PKA pathway acts in response to PTH exposure maintaining levels of cell proliferation, while the PKC pathway is mainly involved for longer exposure to PTH (24 or 48 h), leading to the reduction of cell proliferation and increase of apoptosis. The exposure to PTH reduced the cell number in relation to the control group in a time-dependent manner. In conclusion, PTH modulates odontoblast-like cell proliferative and apoptotic response in a time-dependent manner. Both PKC and PKA pathways participate in PTH-induced modulation in an antagonist mode.
authors.affiliation: Department of Morphology, Division of Histology and Embryology, Piracicaba Dental School, University of Campinas, Av. Limeira 901, Caixa Postal 052 CEP, Piracicaba, São Paulo, 13414-903, Brazil.
authors.forename: Gustavo Narvaes
authors.initials: GN
authors.lastname: Guimarães
authors.forename: Thaisângela Lopes
authors.initials: TL
authors.lastname: Rodrigues
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: de Souza
authors.forename: Sergio Roberto
authors.initials: SR
authors.lastname: Line
authors.forename: Marcelo Rocha
authors.initials: MR
authors.lastname: Marques
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009804:Odontoblasts / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D010281:Parathyroid Hormone; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C