Response of immortalized murine cementoblasts/periodontal ligament cells to parathyroid hormone and parathyroid hormone-related protein in vitro.
Cementum is an essential component of the periodontium, but the mechanisms involved in regulating the activity of this tissue are poorly understood. As one approach to better defining the cellular and molecular properties of cementum and the associated ligament, immortalized murine cell populations expressing gene markers associated with both cementoblasts (CM) and periodontal ligament cells (PDL), termed CM/PDL cells, were established. To further characterize these cells, their responsiveness to parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) was examined. CM/PDL cells were tested for the presence of steady state PTH-1 receptor mRNA using Northern blot analysis. In addition, the ability of PTH and PTHrP to stimulate cAMP production and c-fos mRNA expression in CM/PDL cells was determined, using a cAMP-binding assay and northern blot hybridization, respectively. Rat osteosarcoma cells (ROS 17/2.8) were used as a positive control and human periodontal ligament cells as a negative control. Northern blot analysis demonstrated that cells within the CM/PDL cell population expressed PTH-1 receptor mRNA. Both PTH (1-34) and PTHrP (1-34) increased cAMP and c-fos mRNA in CM/PDL cells. Furthermore, PTHrP treatment for either 24 or 48 h downregulated expression of transcripts for bone sialoprotein, osteocalcin and PTH-1 receptor by CM/PDL cells and abolished CM/PDL cell-mediated mineralization in vitro. These results indicate that cells within the CM/PDL population are targets for PTH and PTHrP action and that PTHrP may play an important part in regulating the biomineralization of cementum.
Ouyang
H
H
Department of Periodontics/Prevention/Geriatrics, The University of Michigan, Ann Arbor, MI 48109-1078, USA. hongjiao@umich.edu
McCauley
L K
LK
Berry
J E
JE
D'Errico
J A
JA
Strayhorn
C L
CL
Somerman
M J
MJ
D000818:Animals; D015152:Blotting, Northern; D002113:Calcification, Physiologic / Q000187:drug effects; D002460:Cell Line; D000242:Cyclic AMP / Q000096:biosynthesis; D003739:Dental Cementum / Q000187:drug effects*; D015536:Down-Regulation; D005819:Genetic Markers; D006801:Humans; D017403:In Situ Hybridization; D058574:Integrin-Binding Sialoprotein; D051379:Mice; D008815:Mice, Inbred Strains; D009363:Neoplasm Proteins / Q000494:pharmacology*; D015675:Osteocalcin / Q000187:drug effects; D012516:Osteosarcoma / Q000378:metabolism / Q000473:pathology; D010281:Parathyroid Hormone / Q000494:pharmacology*; D044162:Parathyroid Hormone-Related Protein; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects*; D011506:Proteins / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000187:drug effects; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D018016:Receptors, Parathyroid Hormone / Q000187:drug effects / Q000235:genetics; D012795:Sialoglycoproteins / Q000187:drug effects; D014407:Tumor Cells, Cultured
D005819:Genetic Markers; C546871:IBSP protein, human; C546872:Ibsp protein, mouse; C546873:Ibsp protein, rat; D058574:Integrin-Binding Sialoprotein; D009363:Neoplasm Proteins; C470121:PTHLH protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D018016:Receptors, Parathyroid Hormone; D012795:Sialoglycoproteins; D015675:Osteocalcin; D000242:Cyclic AMP