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Kanczler JM, Smith EL, Roberts CA, Oreffo ROC. A novel approach for studying the temporal modulation of embryonic skeletal development using organotypic bone cultures and microcomputed tomography. Tissue Eng Part C Methods 2012; 18:747-60. [PMID: 22472170 DOI: 10.1089/ten.tec.2012.0033] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Understanding the structural development of embryonic bone in a three dimensional framework is fundamental to developing new strategies for the recapitulation of bone tissue in latter life. We present an innovative combined approach of an organotypic embryonic femur culture model, microcomputed tomography (μCT) and immunohistochemistry to examine the development and modulation of the three dimensional structures of the developing embryonic femur. Isolated embryonic chick femurs were organotypic (air/liquid interface) cultured for 10 days in either basal, chondrogenic, or osteogenic supplemented culture conditions. The growth development and modulating effects of basal, chondrogenic, or osteogenic culture media of the embryonic chick femurs was investigated using μCT, immunohistochemistry, and histology. The growth and development of noncultured embryonic chick femur stages E10, E11, E12, E13, E15, and E17 were very closely correlated with increased morphometric indices of bone formation as determined by μCT. After 10 days in the organotpyic culture set up, the early aged femurs (E10 and E11) demonstrated a dramatic response to the chondrogenic or osteogenic culture conditions compared to the basal cultured femurs as determined by a change in μCT morphometric indices and modified expression of chondrogenic and osteogenic markers. Although the later aged femurs (E12 and E13) increased in size and structure after 10 days organotpypic culture, the effects of the osteogenic and chondrogenic organotypic cultures on these femurs were not significantly altered compared to basal conditions. We have demonstrated that the embryonic chick femur organotpyic culture model combined with the μCT and immunohistochemical analysis can provide an integral methodology for investigating the modulation of bone development in an ex vivo culture setting. Hence, these interdisciplinary techniques of μCT and whole organ bone cultures will enable us to delineate some of the temporal, structural developmental paradigms and modulation of bone tissue formation to underpin innovative skeletal regenerative technology for clinical therapeutic strategies in musculoskeletal trauma and diseases.
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Affiliation(s)
- Janos M Kanczler
- Bone & Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, United Kingdom.
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Signaling through the extracellular calcium-sensing receptor (CaSR). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:103-42. [PMID: 22453940 DOI: 10.1007/978-94-007-2888-2_5] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The extracellular calcium ([Formula: see text])-sensing receptor (CaSR) was the first GPCR identified whose principal physiological ligand is an ion, namely extracellular Ca(2+). It maintains the near constancy of [Formula: see text] that complex organisms require to ensure normal cellular function. A wealth of information has accumulated over the past two decades about the CaSR's structure and function, its role in diseases and CaSR-based therapeutics. This review briefly describes the CaSR and key features of its structure and function, then discusses the extracellular signals modulating its activity, provides an overview of the intracellular signaling pathways that it controls, and, finally, briefly describes CaSR signaling both in tissues participating in [Formula: see text] homeostasis as well as those that do not. Factors controlling CaSR signaling include various factors affecting the expression of the CaSR gene as well as modulation of its trafficking to and from the cell surface. The dimeric cell surface CaSR, in turn, links to various heterotrimeric and small molecular weight G proteins to regulate intracellular second messengers, lipid kinases, various protein kinases, and transcription factors that are part of the machinery enabling the receptor to modulate the functions of the wide variety of cells in which it is expressed. CaSR signaling is impacted by its interactions with several binding partners in addition to signaling elements per se (i.e., G proteins), including filamin-A and caveolin-1. These latter two proteins act as scaffolds that bind signaling components and other key cellular elements (e.g., the cytoskeleton). Thus CaSR signaling likely does not take place randomly throughout the cell, but is compartmentalized and organized so as to facilitate the interaction of the receptor with its various signaling pathways.
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Saunders MM, Simmerman LA, Reed GL, Sharkey NA, Taylor AF. Biomimetic bone mechanotransduction modeling in neonatal rat femur organ cultures: structural verification of proof of concept. Biomech Model Mechanobiol 2010; 9:539-50. [PMID: 20169394 PMCID: PMC2908729 DOI: 10.1007/s10237-010-0195-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 01/22/2010] [Indexed: 10/19/2022]
Abstract
The goal of this work was to develop and validate a whole bone organ culture model to be utilized in biomimetic mechanotransduction research. Femurs harvested from 2-day-old neonatal rat pups were maintained in culture for 1 week post-harvest and assessed for growth and viability. For stimulation studies, femurs were physiologically stimulated for 350 cycles 24 h post-harvest then maintained in culture for 1 week at which time structural tests were conducted. Comparing 1 and 8 days in culture, bones grew significantly in size over the 7-day culture period. In addition, histology supported adequate diffusion and organ viability at 2 weeks in culture. For stimulation studies, 350 cycles of physiologic loading 24 h post-harvest resulted in increased bone strength over the 7-day culture period. In this work, structural proof of concept was established for the use of whole bone organ cultures as mechanotransduction models. Specifically, this work established that these cultures grow and remain viable in culture, are adequately nourished via diffusion and are capable of responding to a brief bout of mechanical stimulation with an increase in strength.
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Lin Z, Pavlos NJ, Cake MA, Wood DJ, Xu J, Zheng MH. Evidence that human cartilage and chondrocytes do not express calcitonin receptor. Osteoarthritis Cartilage 2008; 16:450-7. [PMID: 17890110 DOI: 10.1016/j.joca.2007.08.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 08/04/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Calcitonin (CT) has been recently shown to exhibit direct protective effects on articular cartilage against joint degenerative disease. It has been proposed that CT might act via the CT receptor (CTR) to activate the cyclic AMP (cAMP) pathway and protect type II collagen degradation. In this study, we investigated the existence of CTR in human articular cartilage and chondrocytes, and examined the potential pharmacological effects and transduction pathway of salmon CT (sCT) in human chondrocytes. METHODS Five human articular cartilage samples were examined for the expression of the CTR by polymerase chain reaction (PCR), immunostaining and Western blot analysis. cAMP levels in human chondrocyte stimulated with sCT were assessed by ELISA. The effect of sCT on the gene expression profiles, including aggrecan, type II collagen, MMP-1, MMP-3 and MMP-13, of human chondrocytes was also examined by relative quantitative Real-time PCR. RESULTS We failed to detect the CTR at both the transcriptional and protein levels in human chondrocytes and cartilage tissue by PCR, immunostaining and Western blotting. cAMP levels were significantly elevated in human chondrocytes by forskolin (100muM) to more than 10-fold (P<0.001), however, were not induced by sCT (10(-7)M, 10(-8)M, 10(-9)M). Real-time PCR analysis demonstrated that sCT slightly reduced the gene expression of MMPs, although this effect was not statistically significant. CONCLUSION In contrary to previous reports, our data indicate that human cartilage and chondrocytes do not express CTR. Furthermore, sCT does not appear to have direct effects on human chondrocytes. We propose that the chondroprotective effect of CT observed in vivo may be indirect via its impact on subchondral bone resorptive activity of osteoclasts.
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Affiliation(s)
- Z Lin
- Centre for Orthopaedic Research, School of Surgery and Pathology, University of Western Australia, Western Australia, Australia
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Ishii A, Nakamura M, Nakamura A, Takeda K, Han B, Kakudo K. Expression of calcitonin receptor in rat mammary gland during lactation. Endocr J 2006; 53:317-24. [PMID: 16710074 DOI: 10.1507/endocrj.k05-131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Calcitonin (CT) and calcitonin receptor (CTR) have been reported to play an important role in mammary tissue during pregnancy, lactation, and involution. In the present study, the expression and distribution of CTR mRNA in rat mammary tissue during pregnancy and lactation were investigated. As measured by real-time RT-PCR, CTR mRNA levels were increased only slightly during pregnancy, but increased markedly immediately postpartum and remained elevated through lactation, with the highest levels observed 14 days postpartum. In situ hybridization analysis showed that intense CTR mRNA signals were detected in the whole mammary gland. We performed immunohistochemistry to determine distribution of CTR in the mammary epithelium. CTR has been reported to act as an amylin receptor when heterodimerized with receptor activity modifying protein-1 (RAMP1) or RAMP3. mRNA expression of RAMP1 and RAMP3 in mammary tissue decreased during pregnancy and lactation, and amylin mRNA was undetectable, suggesting that up-regulated CTR in lactating mammary tissues binds CT rather than amylin. In primary cultures of mammary cells isolated from rat dams 14 days postpartum, CT produced a statistically significant decrease in thymidine incorporation. These results suggest that up-regulation of CTR during lactation may contribute to inhibition of mammary epithelial cell proliferation.
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Affiliation(s)
- Aiko Ishii
- Department of Pathology, Wakayama Medical University, Wakayama, Japan
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Hittmeier LJ, Grapes L, Lensing RL, Rothschild MF, Stahl CH. Genetic background influences metabolic response to dietary phosphorus restriction. J Nutr Biochem 2006; 17:385-95. [PMID: 16311027 DOI: 10.1016/j.jnutbio.2005.08.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Revised: 08/15/2005] [Accepted: 08/15/2005] [Indexed: 11/24/2022]
Abstract
Dietary phosphorus (P) is essential to bone growth and turnover; however, little research has focused on the genetic mechanisms controlling P utilization. Understanding the interactions between genetics and dietary P that optimize bone integrity could provide novel interventions for osteoporosis. Thirty-six pigs from two sire lines known to differ in bone structure [heavier boned (HB) and lighter boned (LB)] were assigned to one of the three diets (P adequate, P repletion or P deficient). After 14 days, bone marrow and intact radial bones were collected. Differences between these lines in growth rate, bone integrity and gene expression within bone marrow were observed. In HB, but not LB, pigs, the P-deficient diet decreased weight gain (P<.01). For both lines, P deficiency caused a reduction in radial bone strength (P<.01), but HB P-deficient animals had greater (P<.10) bone integrity than P-deficient LB pigs. In HB, but not LB, pigs, dietary treatment affected the expression of CALCR (calcitonin receptor) (P<.05), VDR (vitamin D receptor) (P<.04) and IGFBP3 (insulin-like growth factor binding protein 3) (P<.06). There was also a trend of increased IL6 (interleukin-6), TFIIB (transcription initiation factor IIB) and SOX9 (sex determining region Y-box 9) expression with P deficiency in HB, but not LB, pigs. Both genetic backgrounds responded similarly to P deficiency with an increase in the expression of OXTR (oxytocin receptor) and IGF1 (insulin-like growth factor 1). Differences in growth rate, bone integrity and gene expression within the bone marrow suggest a difference in the homeorhetic control of P utilization between these genetic lines. Understanding these differences could lead to novel treatments for osteoporosis and aid in the development of tests for identifying those at risk for this disease.
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Affiliation(s)
- Laura J Hittmeier
- Department of Animal Science and Center for Integrated Animal Genomics, Iowa State University, Ames, IA 50011, USA
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Ikegame M, Ejiri S, Ozawa H. Calcitonin-induced change in serum calcium levels and its relationship to osteoclast morphology and number of calcitonin receptors. Bone 2004; 35:27-33. [PMID: 15207738 DOI: 10.1016/j.bone.2004.03.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Revised: 03/19/2004] [Accepted: 03/19/2004] [Indexed: 10/26/2022]
Abstract
It has been shown that, in live subjects, the ability of calcitonin (CT) to decrease serum calcium (Ca) levels can be lost in response to its continued or repeated administration. The present study investigated the relationship between such changes of in vivo serum Ca levels and the response of osteoclasts to CT administration, including the downregulation of their CT receptors (CTRs). Rats were either given a single injection of CT or repeated injections at either 6- or 24-h intervals, after which their serum Ca levels were evaluated. Their parietal bones were dissected, and the amount of 125I-labeled elcatonin (125I-eCT) binding to their osteoclasts measured using autoradiography. Ultrastructural changes in the osteoclasts were also examined. Twenty-four hours after a single CT administration, serum Ca levels had dropped, and there was an absence of ruffled borders on the osteoclasts. Less 125I-eCT binding to the osteoclast was found than in the control group. Forty-eight and 72 h after CT administration, serum Ca levels had almost returned to control levels, and the osteoclasts showed ruffled borders once again. The amount of 125I-eCT binding to the osteoclast also recovered to control levels. When these osteoclasts were then incubated in CT, their ruffled borders once again disappeared. In the 6-h interval multiple CT administration schedule subjects, upon inspection 72 h after their first administration (6 h following the final one), serum Ca levels were found to have almost returned to control levels with the presence of osteoclast ruffled borders. The amount of 125I-eCT binding to these osteoclasts was remarkably limited, and no disappearance of the ruffled borders occurred in response to additional CT incubation. In the 24-h interval multiple administration schedule subjects, upon inspection 72 h after their first CT administration (24 h following the final one), there was less 125I-eCT binding than in the single-dose subjects tested 24 h after their injection, and the ability of CT to lower their serum Ca levels was reduced. The ability of CT to lower serum Ca levels was therefore related to the response of osteoclasts to the CT (the disappearance of the ruffled borders), and this response was related to the amount of CTRs available for binding with CT on the osteoclast surface. Furthermore, the reduced effectiveness of CT in response to repeated CT administration was found to be related to the downregulation of the CTRs on the osteoclast surface.
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Affiliation(s)
- Mika Ikegame
- Division of Oral Morphology, Science of Functional Recovery and Reconstruction, Okayama Graduate School of Medicine and Dentistry, Shikata-cho, Japan.
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Ishii A, Nakamura M, Nakamura A, Kimura M, Kakudo K. Localization of Calcitonin Receptor mRNA in Rat Kidney: an In Situ Hybridization Study. Acta Histochem Cytochem 2004. [DOI: 10.1267/ahc.37.259] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Aiko Ishii
- Department of Pathology, Wakayama Medical University
- Laboratory of Toxicology, Medicinal Research Laboratories, Taisho Pharmaceutical Co., Ltd
| | - Misa Nakamura
- Department of Pathology, Wakayama Medical University
| | - Atsushi Nakamura
- Laboratory of Toxicology, Medicinal Research Laboratories, Taisho Pharmaceutical Co., Ltd
| | - Masaaki Kimura
- Laboratory of Toxicology, Medicinal Research Laboratories, Taisho Pharmaceutical Co., Ltd
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Pondel MD, Partington GA, Mould R. Tissue-specific activity of the proximal human calcitonin receptor promoter is mediated by Sp1 and an epigenetic phenomenon. FEBS Lett 2003; 554:433-8. [PMID: 14623107 DOI: 10.1016/s0014-5793(03)01216-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
To identify cis-acting sequences transcriptionally regulating the human calcitonin receptor (hCTR) gene, hCTR promoter/luciferase gene constructs were transiently or stably transfected into hCTR-positive and -negative cell lines. Luciferase assays demonstrated that the proximal hCTR promoter (hCTRP1) was transcriptionally active in all cell lines tested. High-level hCTRP1 activity depended on an 11 bp Sp1/Sp3 binding site. Electrophoretic mobility shift assay showed that this region bound the transcription factors Sp1 and Sp3. We further showed that hCTRP1 was strongly activated by the 11 bp Sp1/Sp3 binding site in hCTRP1/luciferase-, Sp1-transfected Drosophila S2 cells. Bisulphite-mediated sequencing of genomic DNA from hCTR-expressing and -non-expressing cell lines demonstrated that the endogenous hCTRP1 was hypomethylated in all cell lines tested. These results suggest that the hCTRP1 is activated by the tissue-ubiquitous transcription factor Sp1 and that an epigenetic process unrelated to CpG methylation represses its activity in hCTR-negative tissues.
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Affiliation(s)
- M D Pondel
- Department of Cellular and Molecular Medicine, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK.
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Mould R, Pondel MD. Calcitonin receptor gene expression in K562 chronic myelogenous leukemic cells. Cancer Cell Int 2003; 3:6. [PMID: 12747809 PMCID: PMC155681 DOI: 10.1186/1475-2867-3-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2003] [Accepted: 04/25/2003] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND: The peptide hormone calcitonin (CT) can significantly effect the proliferation rate of CT receptor (CTR) positive human cancer cells. We wish to identify additional human cancers expressing CTRs and assay the effects of CT on their growth rates and signal transduction pathways. RESULTS: The expression of the human calcitonin receptor (hCTR) gene in the chronic myelogenous leukemia cell line K562 was examined. RT-PCR on total RNA extracted from K562 cells detected the presence of hCTR mRNA. Further analysis demonstrated that multiple hCTR isoforms were present. Incubation of K562 cells with salmon calcitonin (sCT), but not amylin, caused an increase in intracellular levels of cAMP similar to that induced by forskolin treatment. We further demonstrated that butyrate induced erythroid differentiation of K562 cells caused a significant decrease in hCTR mRNA levels. However, phorbol myristate acetate (PMA) induced megakaryocytic differentiation of these cells had no significant effect on hCTR mRNA levels. We demonstrated that exposure to various concentrations of sCT had no effect on the cellular proliferation of K562 cells in vitro. CONCLUSION: Chronic myelogenous k562 cells express multiple CTR isoforms. However, CT does not effect K562 proliferation rates. It is likely that the small increase in intracellular levels of cAMP following CT treatment is not sufficient to interfere with cellular growth.
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Affiliation(s)
- Richard Mould
- St. George's Hospital Medical School Dept. of Cellular Pathology London, SW17 ORE, United Kingdom
| | - Marc D Pondel
- St. George's Hospital Medical School Dept. of Cellular Pathology London, SW17 ORE, United Kingdom
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Kadiyala S, Nagaba S, Takeuchi K, Yukihiro S, Qiu W, Eyes ST, Uskokovic MR, Posner GH, Reddy GS, Guggino SE. Metabolites and analogs of 1alpha,25-dihydroxyvitamin D(3): evaluation of actions in bone. Steroids 2001; 66:347-55. [PMID: 11179743 DOI: 10.1016/s0039-128x(00)00167-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Analogs of 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] activate both genomic mechanisms via the nuclear vitamin D(3) receptor (nVDR) and nongenomic pathways via the plasma membrane vitamin D(3) receptor (pmVDR). Both of these pathways are normally activated by 1alpha,25(OH)(2)D(3), but as a result of synthesis of numerous analogs of 1alpha,25(OH)(2)D(3) these pathways can be distinguished. We used increasing doses of vitamin D(3) analogs to determine their potencies of action on these two distinct pathways, measuring calcium channel potentiation as an indicator of the nongenomic action and measuring increases in osteocalcin mRNA and protein release and bone resorption as indicators of genomic action. We found that both 25(OH)-16,23E-diene-D(3) (R) and 1alpha,25(OH)(2)-16,23E-diene-D(3) (A) are 10-fold more potent than 1alpha,25(OH)(2)D(3) for activation of the nongenomic pathway because double bonds in the side chain and the D ring increase the affinity for calcium channel potentiation. While the C-1alpha-hydroxyl group is not necessary for potentiation of calcium channels, methyl groups at this position can alter the affinity for calcium channel potentiation. On the other hand, 1000 fold higher concentrations of nongenomic analogs were needed compared to 1alpha,25(OH)(2)D(3) to increase osteocalcin mRNA or protein release. 1alpha,25-Dihydroxy-16-ene-23-yne-26,27-hexafluorovitamin D(3), (E) is an agent that is 10 fold more potent than 1alpha,25(OH)(2)D(3) at increasing osteocalcin mRNA and protein release, whereas 1alpha,25(OH)(2)-3-epi-D(3) increases osteocalcin mRNA and protein with a potency over 10 fold lower than 1alpha,25(OH)(2)D(3). These results suggest that double bonds in the side chain and the D ring stabilize action on the nongenomic pathway whereas F(6) on the terminal portion of the side chain increases potency for nVDR. On the other hand, while the C-1alpha-hydroxyl group is necessary for activation of genomic events via nVDR, the activation of nongenomic events occurs in the absence of this group.
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Pondel M. Calcitonin and calcitonin receptors: bone and beyond. Int J Exp Pathol 2000; 81:405-22. [PMID: 11298188 PMCID: PMC2517743 DOI: 10.1046/j.1365-2613.2000.00176.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2000] [Accepted: 10/05/2000] [Indexed: 12/16/2022] Open
Abstract
Calcitonin (CT), a 32 amino acid peptide hormone produced primarily by the thyroid, and its receptor (CTR) are well known for their ability to regulate osteoclast mediated bone resorption and enhance Ca2+ excretion by the kidney. However, recent studies now suggest that CT and CTRs may play an important role in a variety of processes as wide ranging as embryonic/foetal development and sperm function/physiology. In this review article, CT and CTR gene transcription, signal transduction and function are addressed. The effects of CT on the physiology of a variety of organ systems are discussed and the relationship between polymorphisms in the CTR gene and bone mineral density (BMD)/osteoporosis is examined. Recent studies demonstrating the ability of receptor activity modifying proteins (RAMPs) to post-translationally modify the calcitonin receptor-like receptor (CRLR) are detailed and studies employing transgenic mouse technology to determine the temporal and tissue specific transcriptional activity of the CTR gene in vivo are discussed.
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Affiliation(s)
- M Pondel
- Department of Cellular Pathology, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK.
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Jagger C, Chambers T, Pondel M. Transgenic mice reveal novel sites of calcitonin receptor gene expression during development. Biochem Biophys Res Commun 2000; 274:124-9. [PMID: 10903906 DOI: 10.1006/bbrc.2000.3093] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To characterize the tissue and developmental-specific transcriptional activity of the human calcitonin receptor (hCTR) gene in vivo, transgenic mice containing a 4.9-kb hCTR promoter/beta-galactosidase (lacZ) construct were generated. Between 8.5 and 10.5 days of development, lacZ-positive cells were observed on the lateral side of cervical and occipital level somites and in the lateral myotome. LacZ-positive cells also appeared to be migrating from the dermomyotome into the adjacent limb buds, suggesting that the hCTR promoter is active in hypaxial muscle progenitors. By 11.5-16 days of development, novel hCTR expression sites were identified that included limb buds, cornea, retina, skin, intercostal muscles, muscles of the limbs, face, and dorsal root ganglion. hCTR promoter activity in a number of these tissues was repressed at adult stages of development. RT-PCR demonstrated endogenous mCTR mRNA in all lacZ-positive tissues assayed. The developmental regulation of hCTR gene expression in the above tissues suggests that CTRs are likely to play an important role in their morphogenesis.
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Affiliation(s)
- C Jagger
- Department of Histopathology, St. George's Hospital Medical School, Cranmer Terrace, London, SW17 ORE, United Kingdom
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Hebden C, Smalt R, Chambers T, Pondel MD. Multiple promoters regulate human calcitonin receptor gene expression. Biochem Biophys Res Commun 2000; 272:738-43. [PMID: 10860825 DOI: 10.1006/bbrc.2000.2842] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To initiate studies on the transcriptional regulation of the human calcitonin receptor (hCTR) gene, a 4.9-kb hCTR promoter fragment was cloned and hCTR transcriptional initiation sites were mapped in human osteoclasts, kidney, and breast cancer cell line T47D. RT-PCR detected additional hCTR transcripts initiating at least 1 kb 5' to the transcripts mapped above, demonstrating that the hCTR gene is regulated by at least two separate promoters (hCTRP1 and hCTRP2). Transcripts initiating from the upstream promoter (hCTRP2) have a novel 5' untranslated region (5' UTR). Transfection of T47D breast cancer cells with hCTR promoter/luciferase deletion constructs demonstrated that the cloned 4.9-kb hCTR promoter fragment contains both hCTRP1 and hCTRP2 promoters. Fine deletion mapping of the more transcriptionally active hCTRP1 promoter demonstrated that only 97 bp of the hCTRP1 5' flanking region is required for the majority of its transcriptional activity.
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Affiliation(s)
- C Hebden
- Department of Histopathology, St. George's Hospital Medical School, London, United Kingdom
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15
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Jagger C, Gallagher A, Chambers T, Pondel M. The porcine calcitonin receptor promoter directs expression of a linked reporter gene in a tissue and developmental specific manner in transgenic mice. Endocrinology 1999; 140:492-9. [PMID: 9886862 DOI: 10.1210/endo.140.1.6447] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have investigated the transcriptional regulation of the porcine calcitonin (CT) receptor (pCTR) promoter in transgenic mice. A construct containing 2.1 kb pCTR 5' flanking region, fused to a beta-galactosidase (lacZ) gene, was employed for the production of transgenic mice. At 11.5 days of development lacZ expression was observed in the embryonic brain and spinal cord. By 15.5 days post fertilization, lacZ expression was detected in the developing mammary gland, external ear, cartilage primordium of the humerus, and anterior naris (nostril). RT-PCR on RNA from these fetal tissues showed endogenous mouse CTR (mCTR) expression. In neonatal and adult transgenics, lacZ expression was silenced, except in brain, spinal cord, and testis (adults only). Endogenous mCTR gene expression and pCTR promoter activity were corepressed in the same tissues from adult mice. No pCTR promoter activity was detected in the kidney or bone of transgenic animals. This suggests that additional DNA sequences may be required for pCTR promoter activity in these tissues. From these results, we conclude that the pCTR promoter is active only in tissues expressing endogenous mCTR. Many of the these tissues represent previously unknown sites of CTR gene expression. Finally, the developmental regulation of pCTR/mCTR in tissues such as breast and cartilage primordium suggests that CTRs may play a role in the morphogenesis of these tissues.
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Affiliation(s)
- C Jagger
- Department of Histopathology, St. George's Hospital Medical School, London, United Kingdom
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Mazzuoli GF, D'Erasmo E, Pisani D. Primary hyperparathyroidism and osteoporosis. AGING (MILAN, ITALY) 1998; 10:225-31. [PMID: 9801732 DOI: 10.1007/bf03339656] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Primary hyperparathyroidism (PHPT) is considered a cause of secondary osteoporosis as a consequence of its known catabolic effect promoting osteoclast activity and bone resorption. However, recent in vitro and in vivo studies have shown that parathyroid hormone (PTH) may also have an anabolic effect on the mammalian skeleton. These two paradoxical effects of parathyroid hormone are discussed in the light of recent results of basic research, and of bone densitometric and histomorphometric data collected in patients affected by PHPT. Review of the literature leads to the conclusion that in PHPT skeletal damage involves prevalently cortical bone, while the mineral content of trabecular bone is preserved or even increased. On the basis of bone mineral density (BMD) measurements, osteoporosis prevalence in the early postmenopausal period seems to be significantly higher in women affected by PHPT than in the general population. As age progresses, osteoporosis prevalence seems to decrease in PHPT, while it increases exponentially with age in the general population. Similarly in PHPT, vertebral and appendicular fractures occur prevalently in the earlier decades of life with a higher frequency than in normal subjects, while with advancing age the fracture incidence becomes equal to that of the general population. When bone density is measured in lateral projection at lumbar level, BMD values in patients with mild asymptomatic PHPT are significantly higher than in controls. We conclude that PTH hypersecretion may represent a risk factor for osteoporosis and fractures in the young and in the early postmenopausal period, while it may have a protective effect on trabecular bone in elderly postmenopausal women.
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Affiliation(s)
- G F Mazzuoli
- II Clinica Medica, Policlinico Umberto I, La Sapienza University, Roma, Italy
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17
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Ishikawa Y, Wu LN, Genge BR, Mwale F, Wuthier RE. Effects of calcitonin and parathyroid hormone on calcification of primary cultures of chicken growth plate chondrocytes. J Bone Miner Res 1997; 12:356-66. [PMID: 9076578 DOI: 10.1359/jbmr.1997.12.3.356] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Few studies have been directed toward elucidating the action of calcitonin (CT) and parathyroid hormone (PTH) on growth plate chondrocytes, cells directly involved in longitudinal bone growth and provisional calcification. In this study, primary cultures of avian growth plate chondrocytes that calcify without the supplement of beta-glycerophosphate were used to investigate the effects of synthetic human CT and 1-34 bovine PTH on (1) cell division and growth; (2) the deposition of Ca2+ and inorganic phosphate (Pi); (3) the activity of alkaline phosphatase (AP), an enzyme long associated with the mineralization process; (4) the levels of proteoglycans; and (5) the synthesis of collagens. Added continually to preconfluent cultures from day 6 until harvest, CT (1-30 nM) and PTH (0.1-1.0 nM) increased mineral deposition; the maximal increase was seen between days 18-21 at 10 nM CT (175-260%) and 0.5 nM PTH (approximately 170-280%), both p < 0.001. CT had no significant effect on cellular protein, or AP-specific activity, whereas PTH increased cellular protein, DNA, proteoglycan, and collagen content of the cultures in a dosage-dependent manner. AP activity and levels of Type II and X collagens and fibronectin in the culture medium showed a biphasic response to PTH; maximal increases were seen at 0.5 nM between days 15-18. Longer exposure (days 21-27) to PTH at higher levels (5-10 nM) caused a marked decreased in AP activity but a lesser decrease in the collagens. These results indicate that CT and PTH can act directly on chondrocytes to stimulate mineralization, but that PTH specifically stimulated cell division and synthesis of cellular and extracellular proteins by growth plate chondrocytes. The implications of these findings with regard to Ca2+ homeostasis and bone formation are discussed.
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Affiliation(s)
- Y Ishikawa
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, USA
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18
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Weir EC, Lowik CW, Paliwal I, Insogna KL. Colony stimulating factor-1 plays a role in osteoclast formation and function in bone resorption induced by parathyroid hormone and parathyroid hormone-related protein. J Bone Miner Res 1996; 11:1474-81. [PMID: 8889847 DOI: 10.1002/jbmr.5650111014] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Although colony stimulating factor-1 (CSF-1) plays a key role in osteoclast recruitment, studies examining the effect of CSF-1 on mature osteoclasts indicate that it may directly inhibit bone resorption by isolated rat osteoclasts. To define further CSF-1's role in bone remodeling, we examined the effect of neutralizing antisera to CSF-1 on basal and parathyroid hormone (PTH)-induced bone resorption using two organ culture assays designed to examine the recruitment of osteoclast precursors and the activation of mature osteoclasts, respectively. We first assessed whether PTH increases CSF-1 production from bone in organ culture by examining conditioned medium from 19-day-old fetal rat long bones in a mitogenesis assay employing a CSF-1-responsive cell line, CRX-1. Conditioned medium from untreated bones induced a titratable increase in CRX-1 cell proliferation, and treatment of bones with PTH for 72 h caused a significant increase in mitogenic activity. CSF-1 antiserum caused a significant decrease in mitogenic activity in conditioned medium, indicating that bone in organ culture produces CSF-1 constitutively and in response to PTH. To examine bone-derived CSF-1's role in bone resorption, we examined the effect of neutralizing antisera to CSF-1 on basal and PTH-induced bone resorption in the fetal rat long bone assay, which reflects activation of mature osteoclasts. Anti-CSF-1 caused a significant increase in unstimulated and PTH-induced bone resorption compared with control. By contrast, in the fetal mouse metacarpal assay, which examines proliferation and recruitment of osteoclast progenitors and precursors, anti-CSF-1 caused significant inhibition of PTH related protein (PTHrP)-induced bone resorption after 3 and 6 days of incubation. Consistent with these findings, histological examination of cultured 17-day-old fetal metacarpals demonstrated that anti-CSF-1 inhibits the formation of tartrate-resistant acid phosphatase-positive osteoclasts in PTHrP-treated explants, whereas it has no effect on unstimulated bones. We conclude that bone-derived CSF-1 may have a dual role in PTH/PTHrP-induced bone resorption by enhancing the appearance of osteoclast precursors while restraining the resorptive function of mature osteoclasts.
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Affiliation(s)
- E C Weir
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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19
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Abstract
Due to the importance of Ca2+ in the regulation of vital cellular and tissue functions, the concentration of Ca2+ in body fluids is closely guarded by an efficient feedback control system. This system includes Ca(2+)-transporting subsystems (bone, and kidney), Ca2+ sensing, possibly by a calcium-sensing receptor, and calcium-regulating hormones (parathyroid hormone [PTH], calcitonin [CT], and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]). In humans and birds, acute Ca2+ perturbations are handled mainly by modulation of kidney Ca2+ reabsorption and by bone Ca2+ flow under PTH and possibly CT regulation, respectively. Chronic perturbations are also handled by the more sluggish but economic regulatory action of 1,25(OH2)D3 on intestinal calcium absorption. Peptide hormone secretion is modulated by Ca2+ and several secretagogues. The hormones' signal is produced by interaction with their respective receptors, which evokes the cAMP and phospholipase C-IP3-Ca2+ signal transduction pathways. 1,25 (OH)2D3 operates through a cytoplasmic receptor in controlling transcription and through a membrane receptor that activates the Ca2+ and phospholipase C messenger system. The calciotropic hormones also influence processes not directly associated with Ca2+ regulation, such as cell differentiation, and may thus affect the calcium-regulating subsystems also indirectly.
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Affiliation(s)
- S Hurwitz
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
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Giniger MS, Norton L, Sousa S, Lorenzo JA, Bronner F. A human periodontal ligament fibroblast clone releases a bone resorption inhibition factor in vitro. J Dent Res 1991; 70:99-101. [PMID: 1991876 DOI: 10.1177/00220345910700021901] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The conditioned media (CM) obtained from three lines of cloned human periodontal ligament (PDL) cells were analyzed to determine whether they altered the parathyroid hormone (PTH)-stimulated resorption rates (45Ca release) in 48-hour cultures of 45Ca-labeled rat long bones. One PDL cell line, PDL-5, produced a heat-resistant factor in its CM that inhibited the PTH-stimulated resorption by 43.8 +/- 9.7 (SE) percent (p less than or equal to 0.02), whereas the CM from the other cell lines were without statistically significant effect. The CM from the PDL-5 line did not diminish organ culture viability, as determined by 3H-thymidine incorporation, and did not enhance or diminish the resorption-inhibiting activity of calcitonin added to the PTH-stimulated cultures. The addition of CM from PDL-5 did not alter the bone-resorbing effect of interleukin-1 (IL-1). These results indicate that CM from PDL-5 inhibits only the PTH-induced and not the IL-1-mediated resorption processes, whose mechanisms are therefore likely to differ.
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Affiliation(s)
- M S Giniger
- Department of BioStructure and Function, University of Connecticut Health Center, Farmington 06030
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21
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Marks SC, Popoff SN. Bone cell biology: the regulation of development, structure, and function in the skeleton. THE AMERICAN JOURNAL OF ANATOMY 1988; 183:1-44. [PMID: 3055928 DOI: 10.1002/aja.1001830102] [Citation(s) in RCA: 267] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Bone cells compose a population of cells of heterogeneous origin but restricted function with respect to matrix formation, mineralization, and resorption. The local, mesenchymal origin of the cells which form the skeleton contrasts with their extraskeletal, hemopoietic relatives under which bone resorption takes place. However, the functions of these two diverse populations are remarkably related and interdependent. Bone cell regulation, presently in its infancy, is a complicated cascade involving a plethora of local and systemic factors, including some components of the skeletal matrices and other organ systems. Thus, any understanding of bone cell regulation is a key ingredient in understanding not only the development, maintenance, and repair of the skeleton but also the prevention and treatment of skeletal disorders.
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Affiliation(s)
- S C Marks
- Department of Anatomy, University of Massachusetts Medical School, Worcester 01655
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22
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Lerner UH, Gustafson GT. Blood coagulation and bone metabolism: some characteristics of the bone resorptive effect of thrombin in mouse calvarial bones in vitro. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 964:309-18. [PMID: 3126818 DOI: 10.1016/0304-4165(88)90031-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Chronic inflammatory processes are often associated with bone resorption. Stimulated by the current great interest in the role of coagulation factors in inflammation and immune injury, we have studied the effect of thrombin on mouse calvarial bones in vitro. Thrombin caused a dose-dependent (0.1-7 U/ml) stimulation of 45Ca release from neonatal mouse calvarial bones. Thrombin also stimulated the mobilization of stable calcium and inorganic phosphate, the release of 3H from [3H]proline-labelled calvaria, the production of lactate and the release of the lysosomal enzymes, beta-glucuronidase and beta-N-acetylglucosaminidase. Thrombin also enhanced 45Ca release from fetal rat long bones, although this bone resorption assay was less sensitive to thrombin than the mouse calvarial system. The bone resorption stimulatory activity of thrombin in mouse calvaria could be inhibited by calcitonin and an increased concentration of phosphate in the culture medium. Thrombin-induced 45Ca release in mouse calvaria was sensitive to inhibition by hydrocortisone and dexamethasone. By contrast, 45Ca release response to parathyroid hormone was insensitive to corticosteroids. The prostaglandin synthetase inhibitors indomethacin, meclofenamic acid and naproxen and 5,8,11,14-eicosatetraynoic acid reduced 45Ca release from thrombin-stimulated calvaria. However, significant stimulation by thrombin could be achieved also in bones treated with inhibitors of arachidonate metabolism. The results obtained suggest that thrombin can stimulate cell-mediated bone resorption by an osteoclast-dependent mechanism. The mechanism of action may involve both prostaglandin-dependent and prostaglandin-independent pathways. Our findings indicate that thrombin may contribute to the bone resorptive processes seen in periodontal disease and rheumatoid arthritis.
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Affiliation(s)
- U H Lerner
- Department of Oral Pathology, University of Umeå, Sweden
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23
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Lorenzo JA, Sousa S. Phorbol esters stimulate bone resorption in fetal rat long-bone cultures by mechanisms independent of prostaglandin synthesis. J Bone Miner Res 1988; 3:63-7. [PMID: 3145672 DOI: 10.1002/jbmr.5650030110] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The phorbol esters, 12-O-tetradecanoylphorbol-13-acetate (TPA) and phorbol-12,13-didecanoate, which activate the enzyme protein kinase C, stimulated resorption in fetal rat long-bone cultures at concentrations of 1 and 10 microM. This effect appeared specific for active phorbol esters, since the inactive analogue 4-alpha-phorbol-12,13-didecanoate was without effect. The resorptive responses of fetal rat long-bone cultures to active phorbol esters differed from those previously described in newborn mouse calvaria cultures, since resorption stimulated by TPA in the rat long bones was not inhibited by either indomethacin (10 microM) or flufenamic acid (10 microM). However, calcitonin, an inhibitor of osteoclastic resorption, did decrease the response to TPA. There were some similarities between the response of fetal rat long-bone cultures to TPA and their response to epidermal growth factor (EGF). Like EGF, TPA stimulated DNA synthesis in the bones (measured as the incorporation of [3H]-thymidine) at concentrations below those necessary to stimulate resorption. TPA also did not stimulate resorption in the presence of aphidicolin (10 microM), an inhibitor of DNA synthesis that has been previously shown to block the resorptive response of these cultures to EGF. However, the responses of the cultures to TPA and EGF were not identical, since, unlike the effects of EGF, the stimulatory effects of TPA on DNA synthesis were biphasic. These results demonstrate that active phorbol esters stimulate bone resorption in fetal rat long-bone cultures through mechanisms that do not require prostaglandin synthesis but do appear to be mediated by osteoclasts.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J A Lorenzo
- Department of Medicine, Veterans Administration Medical Center, Newington, CT
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24
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Lerner UH, Ransjö M, Ljunggren O. Prostaglandin E2 causes a transient inhibition of mineral mobilization, matrix degradation, and lysosomal enzyme release from mouse calvarial bones in vitro. Calcif Tissue Int 1987; 40:323-31. [PMID: 2440532 DOI: 10.1007/bf02556694] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effect of prostaglandin E2 (PGE2) on the kinetic of bone resorption in vitro was assessed by following the release of minerals and degradation of matrix in cultured mouse calvarial bones. PGE2 (1 and 3 mumol/liter) caused an initial inhibition of the release of 45Ca, stable calcium, and inorganic phosphate from unstimulated calvarial bones. The effect was transient and after 24 and 48 hours the release of 45Ca, stable calcium, and inorganic phosphate from PGE2-treated bones was enhanced. 0.3 mumol/liter of PGE2 stimulated the release of 45Ca after 24 hours, but at this concentration no initial inhibition was observed. The initial inhibitory effect of PGE2 (1 mumol/liter) could be further increased by three structurally different inhibitors of cyclic AMP breakdown. PGE2 (1 mumol/liter) caused not only an initial inhibition of mineral release but also an initial inhibition of matrix degradation, as assessed by the release of 3H from [3H]-proline labeled bones. In addition, PGE2 (3 mumol/liter), in the presence of the phosphodiesterase inhibitor isobutylmethylxanthine, caused a rapid (6 hours) inhibition of the release of the lysosomal enzymes beta-glucuronidase and beta-N-acetyl-glucosaminidase, without affecting the release of the cytosolic enzyme lactate dehydrogenase. Similar specific initial inhibition of lysosomal enzyme release was also seen in the presence of calcitonin and dibutyryl cyclic AMP, but not in the presence of parathyroid hormone (PTH). Neither PGE2 nor the phosphodiesterase inhibitors rolipram and Ro 20.1724, could inhibit the initial stages of PTH-induced 45Ca release. Nor did PGE2 inhibit the stimulation of radioactive calcium mobilization induced by 1 alpha (OH)-vitamin D3.(ABSTRACT TRUNCATED AT 250 WORDS)
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25
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Rappaport MS, Stern PH. Parathyroid hormone and calcitonin modify inositol phospholipid metabolism in fetal rat limb bones. J Bone Miner Res 1986; 1:173-9. [PMID: 3503534 DOI: 10.1002/jbmr.5650010202] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Inositol-containing phospholipids are believed to be intimately involved in the first steps of cellular signalling by certain hormones and neurotransmitters. We examined whether parathyroid hormone (PTH) and calcitonin (CT), two hormones that affect bone physiology, would elicit changes in inositol-phospholipid metabolism in cultured bone. [3H]inositol readily entered into the tissue phospholipid pool in fetal rat limb bones, and incorporated into phosphatidylinositol (92.9%), phosphatidylinositol-4-P (4.5%), and phosphatidylinositol-4,5-P2 (2.6%). PTH enhanced the incorporation of inositol into PtdIns in limb bones following 2- or 24-h hormone treatments. The effect of PTH was dose dependent (EC50 of 0.3-0.4 nM) and occurred in a concentration range similar to that for hormone-stimulated bone resorption. In contrast, 24-h treatment with CT-inhibited inositol incorporation, also in a dose-dependent manner. Two-hour CT treatment had variable effects on labeling. CT inhibited the stimulatory effect of PTH at both 2 and 24 h. The effects induced by PTH and CT were specific for PtdIns and were independent of the [3H]inositol pool size. These results indicate that inositol-phospholipid turnover can be modified during the action of these hormones on bone tissue. Although the time course of hormone-stimulated inositol incorporation observed here is slower than that found in other tissues, the change in phosphatidylinositol metabolism could mediate delayed effects of PTH or CT. Alternatively, alterations induced by PTH and CT in bone cell membranes, cell populations, or in the mineralized matrix could conceivably result in secondary changes in phosphatidylinositol metabolism.
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Affiliation(s)
- M S Rappaport
- Department of Pharmacology, Northwestern University, Chicago, IL 60611
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26
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Hedlund T, Hulth A, Johnell O. The early effects of EDTA colchicine and azetazolamide on the number of osteoclasts and the calcium in rats. ACTA ORTHOPAEDICA SCANDINAVICA 1982; 53:753-6. [PMID: 6814166 DOI: 10.3109/17453678208992287] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Changes in the number of osteoclasts in rats after injection of ethylene diamine tetra-acetic acid (EDTA), azetazolamide or colchicine were studied using succinic dehydrogenase staining of osteoclasts. As early as 10 minutes after injection EDTA caused a significant increase in the number of osteoclasts. Azetazolamide and colchicine resulted in a decrease in the number of osteoclasts, apparent after 30 minutes and 60 minutes, respectively. The changes in total serum calcium after EDTA and azetazolamide administration took place at the same rate. However, azetazolamide had an effect which was the reverse of the effect of EDTA. It caused an increase in calcium in spite of a decreased number of osteoclasts. The results of this investigation confirm those of earlier studies, showing very rapid changes in the number of osteoclasts caused by substances giving rapid changes in serum calcium.
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Abstract
This report summarizes the relationship of calcitonin to phosphate. The hypocalcemic action of calcitonin is dependent upon phosphate, while the hypophosphatemic action is independent of calcium. Calcitonin moves phosphate into bone cells and bone fluid in contrast to reducing the movement of calcium from bone to blood. Calcitonin acts rapidly and at low doses on the osteocytes and lining cells at bone surfaces. Morphological changes can be identified within 7 min. This action causes the accumulation of an electron-dense material both in bone lining cells and their microenvironment. It is postulated that both the hypocalcemic action of calcitonin and its ability to cause an accumulation of material at bone surfaces may result from the movement of phosphate into these areas. The biochemical action which could produce the phosphate movement is unknown. The possibility is suggested that calcitonin increases phosphate transport into bone cells.
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28
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Rosen V, Clark NB. Effects of parathyroid hormone and calcitonin on embryonic chick bone in organ culture. Gen Comp Endocrinol 1981; 44:319-23. [PMID: 7286615 DOI: 10.1016/0016-6480(81)90008-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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29
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Rosen V, Laverty G, Clark NB. Stimulation of calcium release from cultured embryonic chick bones by parathyroid glands of the freshwater turtle. Gen Comp Endocrinol 1980; 41:150-5. [PMID: 7419042 DOI: 10.1016/0016-6480(80)90138-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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30
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Price P, Lothringer J, Nishimoto S. Absence of the vitamin K-dependent bone protein in fetal rat mineral. Evidence for another gamma-carboxyglutamic acid-containing component in bone. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)85831-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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31
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Severson AR. Colchicine stimulation of hyaluronate synthesis and secretion in bone organ culture. J Cell Physiol 1979; 101:341-8. [PMID: 511956 DOI: 10.1002/jcp.1041010213] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Abstract
The process of connective tissue breakdown in chronic otitis media is described in the context of recent advances in our understanding of collagen degradation and bone resorption. The significance of the initial step in collagen breakdown, brought about by the action of a specific collagen dissolving enzyme is emphasized in terms of recent studies in other chronic inflammatory diseases characterized by connective tissue breakdown. Bone resorption, a characteristic feature of chronic otitis media, requires the breakdown of collagen, which comprises over 90 percent of bone protein. Evidence in support of collagenase in bone resorption from adjacent tissue (in this case, inflammatory connective tissue) would require identification of the enzyme in cells involved in the inflammatory process adjacent to the resorbing bone. Collagenase was found localized in frozen sections of canal wall skin, middle ear granulation and in cholesteatoma by a specific binding of the enzyme with an antiserum produced against purified human skin collagenase. The antigen antibody complex was labelled with fluorescein. Collagenase appeared in the subepithelial connective tissue of cholesteatoma, granulation tissue from the middle ear and the dermis of canal skin; but was not seen in the keratin layer, epithelium or the epidermal appendages. The enzyme appeared within certain fibroblasts, macrophages and endothelial cells of capillary buds. Collagenase enhanced by chronic inflammation attacks the intact collagen molecule, making it susceptible to further digestion by other proteases that are also products of inflammation. This process brings about resorption of connective tissue and bone.
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Parfitt AM. The actions of parathyroid hormone on bone: relation to bone remodeling and turnover, calcium homeostasis, and metabolic bone diseases. II. PTH and bone cells: bone turnover and plasma calcium regulation. Metabolism 1976; 25:909-55. [PMID: 181659 DOI: 10.1016/0026-0495(76)90124-4] [Citation(s) in RCA: 125] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Kinetic and morphologic studies in patients with parathyroid disease, and a wide variety of studies in experimental animals indicate that one major effect of PTH is to increase the proliferation of osteoprogenitor cells into osteoclasts and so to increase bone turnover. PTH stimulates bone cells by increasing cell membrane permeability to calcium and consequently increasing calcium influx and by activating membrane-bound adenyl-cyclase. It is likely that the former event precedes the latter and that calcium is the second messenger and cyclic AMP the third messenger. PTH increases the production by bone cells of lactate, citric and carbonic acids, lysosomal enzymes, collagenase, and hyaluronic acid, some or all of which are concerned in the mechanism of bone resorption. With the exception of lactate which probably comes mainly from osteocytes, the increase in metabolic activity is largely due to the increase in the number of osteoclasts. There is also ultrastructural, biochemical, and biophysical evidence that PTH stimulates existing osteoclasts, but this most likely represents the transformation of inactive cells into an active state, and is a transient and nonsustainable effect. As yet, there is no evidence that either increased osteoprogenitor cell proliferation or increased osteoclast activity is mediated by adenyl-cyclase activation. PTH also acts on the deep osteocyte to cause rapid mobilization of calcium from the zone of hypomineralized metabolically active perilacunar bone. This effect is mediated by adenyl-cyclase activation and is preceded by a slight fall in plasma calcium probably due to the movement of calcium into bone cells. The function of this rapid hypercalcemic response to PTH is correct errors in the prevailing steady-state level of plasma calcium...
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Marks SC. A discrepancy between measurements of bone resorption in vivo and in vitro in newborn osteopetrotic rats. THE AMERICAN JOURNAL OF ANATOMY 1974; 141:329-39. [PMID: 4447075 DOI: 10.1002/aja.1001410305] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Smith DM, Johnston CC, Severson AR. Studies of the metabolism of separated bone cells. I. Techniques of separation and identification. CALCIFIED TISSUE RESEARCH 1973; 11:56-69. [PMID: 4572373 DOI: 10.1007/bf02546595] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Talmage RV, Cooper CW, Park HZ. Regulation of calcium transport in bone by parathyroid hormone. VITAMINS AND HORMONES 1971; 28:103-40. [PMID: 4334955 DOI: 10.1016/s0083-6729(08)60889-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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43
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Steinberg J, Nichols G. A comparative study in bone and kidney of nucleotide and RNA synthesis. BIOCHIMICA ET BIOPHYSICA ACTA 1971; 228:173-82. [PMID: 5546559 DOI: 10.1016/0005-2787(71)90557-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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44
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Nichols G. Bone resorption and calcium homeostasis: one process or two? CALCIFIED TISSUE RESEARCH 1970:Suppl:61-3. [PMID: 4316911 DOI: 10.1007/bf02152352] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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45
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Reynolds JJ, Dingle JT. A sensitive in vitro method for studying the induction and inhibition of bone resorption. CALCIFIED TISSUE RESEARCH 1969; 4:339-49. [PMID: 5443725 DOI: 10.1007/bf02279136] [Citation(s) in RCA: 113] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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46
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Reynolds JJ, Dingle JT. Time course of action of calcitonin on resorbing mouse bones in vitro. Nature 1968; 218:1178-9. [PMID: 5656645 DOI: 10.1038/2181178a0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Ziegler R, Riechmann K, Grebenstein R, Pfeiffer EF. [On the hypocalcemic effect of endogenous and exogenous thyrocalcitonin in the rat]. KLINISCHE WOCHENSCHRIFT 1968; 46:587-93. [PMID: 5726585 DOI: 10.1007/bf01747838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Raisz LG, Au WY, Friedman J, Niemann I. Thyrocalcitonin and bone resorption. Studies employing a tissue culture bioassay. Am J Med 1967; 43:684-90. [PMID: 6054837 DOI: 10.1016/0002-9343(67)90110-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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