Abstract
Periodontal ligament (PDL) cells exhibit several osteoblastic traits and are parathyroid hormone (PTH)-responsive providing evidence for a role of these cells in dental hard-tissue repair. To examine the hypothesis that PDL cells respond to PTH stimulation with changes in proliferation and apoptotic signaling through independent but convergent signaling pathways, PDL cells were cultured from human bicuspids obtained from six patients. PDL cells at different states of maturation were challenged with PTH(1–34) intermittently for 0, 1, or 24 h/cycle or exposed continuously. Specific inhibitors to protein kinases A and C (PKA, PKC) and the mitogen-activated protein kinase cascade (MAPK) were employed. At harvest, the cell number, BrdU incorporation, and DNA fragmentation were determined by means of cell counting and immunoassays. Intermittent PTH(1–34) caused a significant increase in cell number in confluent cells as opposed to a reduction in pre-confluent cells. In confluent cells, the effect resulted from a significant increase in proliferation, whereas DNA fragmentation was reduced when PTH(1–34) was administered for 1 h/cycle but increased after PTH(1–34) for 24 h/cycle. Inhibition of PKC inhibited PTH(1–34)-induced proliferation but enhanced apoptosis. Inhibition of PKA enhanced proliferation and DNA fragmentation. Similar results were obtained in less mature cells, although, in the presence of the PKA inhibitor, the PTH(1–34)-induced changes were more pronounced than in confluent cells. In the presence of the MAPK inhibitor, all of the parameters examined were reduced significantly in both maturation states. Thus, PTH(1–34) mediates proliferative and apoptotic signaling in human PDL cells in a maturation-state-dependent manner via PKC-dependent and PKA-dependent pathways.
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References
Adachi N, Yamaguchi K, Miyaki Y, Honda S, Nagasaki K, Akiyama Y, Adachi I, Abe K (1990) Parathyroid hormone related protein is a possible autocrine growth inhibitor for lymphocytes. Biochem Biophys Res Commun 166:1088–1094
Babich M, Choi H, Johnson RM, King KL, Alford NE, Nissenson RA (1991) Thrombin and parathyroid hormone mobilize intracellular calcium in rat osteosarcoma cells by distinct pathways. Endocrinology 129:1463–1470
Basdra EK, Komposch G (1997) Osteoblast-like properties of human periodontal ligament cells: an in vitro analysis. Eur J Orthod 19:615–621
Bellido T, Ali AA, Plotkin LI, Fu Q, Gubrij I, Roberson PK, Weinstein RS, O’Brien CA, Manolagas SC, Jilka RL (2003) Proteasomal degradation of Runx2 shortens parathyroid hormone-induced anti-apoptotic signaling in osteoblasts. A putative explanation for why intermittent administration is needed for bone anabolism. J Biol Chem 278:50259–50272
Benitez-Verguizas J, Esbrit P (1994) Proliferative effect of parathyroid hormone-related protein on the hypercalcemic walker 256 carcinoma cell line. Biochem Biophys Res Commun 198:1281–1289
Bos MP, Meer JM van der, Feyen JH, Herrmann-Erlee MP (1996) Expression of the parathyroid hormone receptor and correlation with other osteoblastic parameters in fetal rat osteoblasts. Calcif Tissue Int 58:95–100
Burgering BMT, Bos JL (1995) Regulation of ras-mediated signaling: more than one way to skin a cat. Trends Biochem Sci 20:18–22
Chen H, Demiralp B, Schneider A, Koh A, Silve C, Wang C, McCauley LK (2002) Parathyroid hormone and parathyroid hormone-related protein exert both pro- and anti-apoptotic effects in mesenchymal cells. J Biol Chem 277:19374–19381
Chou AM, Sae-Lim V, Lim T, Schantz J, Teoh S, Chew A (2002) Culturing and characterization of human periodontal ligament fibroblasts—a preliminary study. Mater Sci Eng 20:77–83
Civitelli R, Reid IR, Westbrook S, Avioli LV, Hruska KA (1998) PTH elevates inositol polyphosphates and diacylglycerol in a rat osteoblast-like cell line. Am J Physiol 255:E660–E667
Cole JA (1999) Parathyroid hormone activates mitogen-activated protein kinase in opossum kidney cells. Endocrinology 140:5771–5779
Evan G, Littlewood T (1998) A matter of life and cell death. Science 281:1317–1321
Habener JF, Rosenblatt M, Potts JT Jr (1984) Parathyroid hormone: biochemical aspects of biosynthesis, secretion, action on anabolism. Physiol Rev 64: 984–1053
Iida-Klein A, Zhou H, Lu S, Levine LR, Ducayen-Knowles M, Dempster DW, Nieves J, Lindsay R (2002) Anabolic action of parathyroid hormone is skeletal site specific at the tissue and cellular levels in mice. J Bone Miner Res 17:808–816
Jilka RL, Weinstein RS, Bellido T, Roberson P, Parfitt AM, Manolagas SC (1999) Increased bone formation by prevention of osteoblast apoptosis with parathyroid hormone. J Clin Invest 104:439–446
Kaiser SM, Laneauville P, Bernier SM, Rhim JS, Kremer R, Goltzman D (1992) Enhanced growth of a human keratinocyte cell line induced by antisense RNA for parathyroid hormone-related peptide. J Biol Chem 267:13623–13628
Koike T, Iwamoto M, Shimazu A, Nakashima K, Suzuki F, Kato Y (1990) Potent mitogenic effects of parathyroid horone (PTH) on embryonic chick and rabbit chondrozytes. J Clin Invest 85:626–631
Kondo H, Ohyama T, Ohya K, Kasugai S (1997) Temporal changes of mRNA expression of matrix proteins and parathyroid hormone and parathyroid hormone-related protein (PTH/PTHrP) receptor in bone development. J Bone Miner Res 12:2089–2097
Lee SK, Lorenzo JA (1999) Parathyroid hormone stimulates TRANCE and inhibits osteoprotegerin messenger ribonucleic acid expression in murine bone marrow cultures: correlation with osteoclast-like cell formation. Endocrinology 140:3552–3561
Lossdörfer S, Götz W, Jäger A (2005) PTH(1–34) affects OPG production in human PDL cells in vitro. J Dent Res 84:634–638
Lossdörfer S, Stier S, Götz W, Jäger A (2006) Maturation-state dependent response of human periodontal ligament cells to an intermittent parathyroid hormone exposure in vitro. J Periodontal Res 41:62–72
Lucas M, Sanchez-Margalet V (1995) Protein kinase C involvement in apoptosis. Gen Pharmacol 26:881–887
Ma YL, Cain R, Halladay D, Yang X, Zeng Q, Miles R, Chandrasekhar S, Martin TJ, Onyia JE (2001) Catabolic effects of continuous human PTH (1–38) in vivo is associated with sustained stimulation of RANKL and inhibition of osteoprotegerin and gene-associated bone formation. Endocrinology 142:4047–4054
MacDonald BR, Gallagher JA, Russell RGG (1996) Parathyroid hormone stimulates the proliferation of cells derived from human bone. Endocrinology 118:2445–2449
Machwate M, Rodan SB, Rodan GA, Harada SI (1998) Sphingosine kinase mediates cyclic AMP suppression of apoptosis in rat periosteal cells. Mol Pharmacol 54:70–77
McCauley LK, Koh AJ, Beecher CA, Cui Y, Rosol TJ, Franceschi RT (1996) PTH/PTHrP receptor is temporally regulated during osteoblast differentiation and is associated with collagen synthesis. J Cell Biochem 61:638–647
Nakajima A, Shimoji N, Shiomi K, Shimizu S, Moriya H, Einhorn TA, Yamazaki M (2002) Mechanisms for the enhancement of fracture healing in rats treated with intermittent low-dose human parathyroid hormone (1–34). J Bone Miner Res 17:2038–2047
Nohutcu RM, Somerman MJ, McCauley LK (1995) Dexamethasone enhances the effects of parathyroid hormone on human periodontal ligament cells in vitro. Calcif Tissue Int 56:571–577
Onishi T, Hruska K (1997) Expression of p27Kip1 in osteoblast-like cells during differentiation with parathyroid hormone. Endocrinology 138:1995–2004
Ouyang H, McCauley L, Berry J, D’Errico J, Strayhorn C, Somerman M (2000) Response of immortalized murine cementoblasts/periodontal ligament cells to parathyroid hormone and parathyroid hormone related protein in vitro. Arch Oral Biol 45:293–303
Pages G, Lenormand P, L’Allemain G, Chambard JC, Meloche S, Pouyssegur J (1993) Mitogen-activated protein kinase p42mapk and p44mapk are required for fibroblast proliferation. Proc Natl Acad Sci USA 90:8319–8323
Partridge NC, Alcorn D, Michelangeli VP, Kemp BE, Ryan GB, Martin TJ (1981) Functional properties of hormonally responsive cultured normal and malignant rat osteoblastic cells. Endocrinology 108:213–219
Qin L, Raggatt LJ, Partridge NC (2004) Parathyroid hormone: a double-edged sword for bone metabolism. Trends Endocrinol Metab 15:60–65
Sabatini M, Lesur C, Pacherie M, Pastoureau P, Kucharczyk N, Fauchiere JL, Bonnet J (1996) Effects of parathyroid hormone and agonists of the adenyl cyclase and protein kinase C pathways on bone cell proliferation. Bone 18:59–65
Scorrano L, Oakes SA, Opferman JT, Cheng EH, Sorcinelli MD, Pozzan T, Korsmeyer SJ (2003) BAX and BAK regulation of endoplasmic reticulum Ca2+: a control point for apoptosis. Science 300:135–139
Scutt A, Duvos C, Lauber J, Mayer H (1994) Time-dependent effects of parathyroid hormone and prostaglandin E2 on DNA synthesis by periosteal cells from embryonic chick calvariae. Calcif Tissue Int 55:208–215
Sheikh M, Fornance A (2000) Death and decoy receptors and p53-mediated apoptosis. Leukemia 14:1509–1513
Siddhanti SR, Hartle JE 2nd, Quarles LD (1995) Forskolin inhibits protein kinase C-induced mitogen activated protin kinase activity in MC3T3-E1 osteoblasts. Endocrinology 136:4834–4841
Sömjen D, Zor U, Kaye AM, Harell A, Binderman I (1987) Parathyroid hormone induction of creatine kinase activity and DNA synthesis is mimicked by phospholipase C, diacyglycerol and phorbol ester. Biochim Biophys Acta 931:215–223
Sömjen D, Binderman I, Schlüter KD, Wingender F, Mayer H, Kaye AM (1990) Stimulation by defined parathryoid hormone fragments of cell proliferation in skeletal-derived cell cultures. Biochem J 272:781–785
Swarthout JT, Doggett TA, Lemker JL, Partridge NC (2001) Stimulation of extracellular signal-regulated kinases and proliferation in rat osteoblastic cells by parathyroid hormone is protein kinase C-dependent. J Biol Chem 276:7586–7592
Troppmair J, Bruder JT, Munoz H, Lloyd PA, Kyriakis J, Banerjee P, Avruch J, Rapp UR (1994) Mitogen-activated protein kinase/extracellular signal-regulated protein kinase activation by oncogenes, serum, and 12-O-tetradecanoylphorbol-13-acetate requires raf and is necessary for transformation. J Biol Chem 269:7030–7035
Turner PR, Mefford S, Christakos S, Nissenson RA (2000) Apoptosis mediated by activation of the G protein-coupled receptor for parathyroid hormone (PTH)/PTH-related protein (PTHrP). Mol Endocrinol 14:241–254
Verheijen MH, Defize LH (1995) Parathyroid hormone inhibits mitogen-activated protein kinase activation in osteosarcoma cells via a protein kinase A-dependent pathway. Endocrinology 136:3331–3337
Yang ZJ, Cheng V, Barnes S, Cavalho L, Sindrey D (1997) Pulsatile parathyroid hormone (PTH) treatment increases bone formation in vitro in fetal rat calvarial cell (FRCC) culture system. J Bone Miner Res 12 (Suppl 1):S317
Zerega B, Cermelli S, Bianco P, Cancedda R, Cancedda FD (1999) Parathyroid hormone [PTH(1–34)] and parathyroid hormone-related protein [PTHrP(1–34)] promote reversion of hypertrophic chondrocytes to a prehypertrophic proliferating phenotype and prevent terminal differentiation of osteoblast-like cells. J Bone Miner Res 14:1281–1289
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The authors thank K. Hoffmann for technical assistance and C. Maelicke for her help in preparing the manuscript.
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This research was supported by research grants from the BONFOR program (O-135.0006) of the University of Bonn, Bonn, Germany and the Deutsche Forschungsgemeinschaft (DFG; LO-1181/1-1).
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Lossdörfer, S., Götz, W., Rath-Deschner, B. et al. Parathyroid hormone(1–34) mediates proliferative and apoptotic signaling in human periodontal ligament cells in vitro via protein kinase C-dependent and protein kinase A-dependent pathways. Cell Tissue Res 325, 469–479 (2006). https://doi.org/10.1007/s00441-006-0198-0
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DOI: https://doi.org/10.1007/s00441-006-0198-0