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Sheng MHC, Rundle CH, Baylink DJ, Lau KHW. Conditional Deletion of Gremlin-1 in Cathepsin K-expressing Mature Osteoclasts Altered the Skeletal Response to Calcium Depletion in Sex-Dependent Manner. Calcif Tissue Int 2025; 116:28. [PMID: 39789342 PMCID: PMC11717885 DOI: 10.1007/s00223-024-01337-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2024] [Accepted: 12/16/2024] [Indexed: 01/12/2025]
Abstract
This study assessed the novel concept that osteoclast-derived Grem1 has regulatory functions in the skeletal response to calcium stress using an osteoclastic Grem1 conditional knockout (cKO) mouse model. The calcium stress was initiated by feeding cKO mutants and wildtype (WT) littermates a calcium-deficient diet for 2 weeks. Deletion of Grem1 in mature osteoclasts did not affect developmental bone growth nor basal bone turnover. In response to calcium depletion, male cKO mutants showed greater increases in osteoclastic resorption and trabecular bone loss than male WT littermates, indicating an enhanced skeletal sensitivity to calcium depletion in male mutants. The enhanced sensitivity to calcium depletion was sex-dependent, as female cKO mutants showed lower increases in osteoclastic resorption and bone loss than female WT littermates as well as male cKO mutants. The sex disparity in osteoclastic resorption response to calcium stress was intrinsic to osteoclasts since osteoclasts of male but not female cKO mutants showed greater in vitro bone resorption activity than osteoclasts of WT littermates of respective sex. Male cKO mutants displayed smaller bone formation response to calcium depletion than male WT littermates, while female mutants showed bigger bone formation response than female WT littermates, indicating that cKO mutants also displayed sex disparity in bone formation response. The sex disparity in bone formation response was not caused by intrinsic differences in osteoblasts but might be due to sex-dependent differential osteoclastic release of osteogenic factors. In summary, osteoclast-derived gremlin-1 has complicated and sex-dependent regulatory roles in skeletal response to calcium stress.
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Affiliation(s)
- Matilda H-C Sheng
- Musculoskeletal Disease Center (151), Jerry L. Pettis Memorial VA Medical Center, VA Loma Linda Healthcare System, 11201 Benton Street, Loma Linda, CA, 92357, USA.
- Department of Medicine and Biochemistry, Loma Linda University School of Medicine, Loma Linda, CA, USA.
| | - Charles H Rundle
- Musculoskeletal Disease Center (151), Jerry L. Pettis Memorial VA Medical Center, VA Loma Linda Healthcare System, 11201 Benton Street, Loma Linda, CA, 92357, USA
- Department of Medicine and Biochemistry, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - David J Baylink
- Department of Medicine and Biochemistry, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Kin-Hing William Lau
- Musculoskeletal Disease Center (151), Jerry L. Pettis Memorial VA Medical Center, VA Loma Linda Healthcare System, 11201 Benton Street, Loma Linda, CA, 92357, USA
- Department of Medicine and Biochemistry, Loma Linda University School of Medicine, Loma Linda, CA, USA
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2
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Steinacker VC, Renner T, Holzmeister I, Gubik S, Müller-Richter U, Breitenbücher N, Fuchs A, Straub A, Scheurer M, Kübler AC, Gbureck U. Biological and Mechanical Performance of Dual-Setting Brushite-Silica Gel Cements. J Funct Biomater 2024; 15:108. [PMID: 38667565 PMCID: PMC11051121 DOI: 10.3390/jfb15040108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/09/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Bone defects resulting from trauma, diseases, or surgical procedures pose significant challenges in the field of oral and maxillofacial surgery. The development of effective bone substitute materials that promote bone healing and regeneration is crucial for successful clinical outcomes. Calcium phosphate cements (CPCs) have emerged as promising candidates for bone replacement due to their biocompatibility, bioactivity, and ability to integrate with host tissues. However, there is a continuous demand for further improvements in the mechanical properties, biodegradability, and bioactivity of these materials. Dual setting of cements is one way to improve the performance of CPCs. Therefore, silicate matrices can be incorporated in these cements. Silicate-based materials have shown great potential in various biomedical applications, including tissue engineering and drug delivery systems. In the context of bone regeneration, silicate matrices offer unique advantages such as improved mechanical stability, controlled release of bioactive ions, and enhanced cellular responses. Comprehensive assessments of both the material properties and biological responses of our samples were conducted. Cytocompatibility was assessed through in vitro testing using osteoblastic (MG-63) and osteoclastic (RAW 264.7) cell lines. Cell activity on the surfaces was quantified, and scanning electron microscopy (SEM) was employed to capture images of the RAW cells. In our study, incorporation of tetraethyl orthosilicate (TEOS) in dual-curing cements significantly enhanced physical properties, attributed to increased crosslinking density and reduced pore size. Higher alkoxysilyl group concentration improved biocompatibility by facilitating greater crosslinking. Additionally, our findings suggest citrate's potential as an alternative retarder due to its positive interaction with the silicate matrix, offering insights for future dental material research. This paper aims to provide an overview of the importance of silicate matrices as modifiers for calcium phosphate cements, focusing on their impact on the mechanical properties, setting behaviour, and biocompatibility of the resulting composites.
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Affiliation(s)
- Valentin C. Steinacker
- Department of Oral & Maxillofacial Plastic Surgery, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Tobias Renner
- Department of Oral & Maxillofacial Plastic Surgery, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Ib Holzmeister
- Department for Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Sebastian Gubik
- Department of Oral & Maxillofacial Plastic Surgery, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Urs Müller-Richter
- Department of Oral & Maxillofacial Plastic Surgery, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Niko Breitenbücher
- Department of Oral & Maxillofacial Plastic Surgery, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Andreas Fuchs
- Department of Oral & Maxillofacial Plastic Surgery, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Anton Straub
- Department of Oral & Maxillofacial Plastic Surgery, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Mario Scheurer
- Department of Cranio-Maxillo-Facial-Surgery, German Armed Forces Hospital Ulm, 89081 Ulm, Germany
| | - Alexander C. Kübler
- Department of Oral & Maxillofacial Plastic Surgery, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Uwe Gbureck
- Department for Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
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Preliminary Report: Osteoarthritis and Rheumatoid Arthritis Synovial Fluid Increased Osteoclastogenesis In Vitro by Monocyte Differentiation Pathway Regulating Cytokines. Mediators Inflamm 2022; 2022:2606916. [PMID: 35693109 PMCID: PMC9175097 DOI: 10.1155/2022/2606916] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 04/04/2022] [Accepted: 04/22/2022] [Indexed: 11/18/2022] Open
Abstract
Background. Rheumatoid arthritis (RA) and osteoarthritis (OA) are common joint diseases associated with changes in local, as well as systemic bone structure and osteoclast function. We investigated how the different soluble inflammatory stimuli in these diseases can affect osteoclastogenesis and bone resorption in vitro. Methods. Human peripheral blood mononuclear cell-derived osteoclasts were cultured on bone slices with serum from treatment-naïve RA patients and healthy controls and with synovial fluid samples acquired from RA and OA patients. The concentrations of 29 different cytokines and related proteins, including RANKL and OPG, were analyzed in the fluids tested. Results. RA serum and synovial fluid increased both osteoclastogenesis and bone resorption. Osteoclastogenesis and activity increased more in the cultures containing OA than RA synovial fluid. The osteoclasts cultured in different culture media exhibited different phenotypes, especially the cells cultured with OA synovial fluid were generally larger and had more nuclei. A general increase in proinflammatory cytokines in RA synovial fluid and serum was found. Surprisingly, OA synovial fluid showed lower levels of osteoclastogenesis inhibiting cytokines, such as IL-4 and IL-10, than RA synovial fluid, which at least partly explains more pronounced osteoclastogenesis. No significant difference was found in RANKL or OPG levels. Conclusion. The proinflammatory stimulus in OA and RA drives the monocyte differentiation towards inflammatory osteoclastogenesis and altered osteoclast phenotype.
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4
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Kong L, Smith W, Hao D. Overview of RAW264.7 for osteoclastogensis study: Phenotype and stimuli. J Cell Mol Med 2019; 23:3077-3087. [PMID: 30892789 PMCID: PMC6484317 DOI: 10.1111/jcmm.14277] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 02/13/2019] [Accepted: 02/16/2019] [Indexed: 12/25/2022] Open
Abstract
Bone homeostasis is preserved by the balance of maintaining between the activity of osteogenesis and osteoclastogenesis. However, investigations for the osteoclastogenesis were hampered by considerable difficulties associated with isolating and culturing osteoclast in vivo. As the alternative, stimuli‐induced osteoclasts formation from RAW264.7 cells (RAW‐OCs) have gain its importance for extensively osteoclastogenic study of bone diseases, such as rheumatoid arthritis, osteoporosis, osteolysis and periodontitis. However, considering the RAW‐OCs have not yet been well‐characterized and RAW264.7 cells are polymorphic because of a diverse phenotype of the individual cells comprising this cell linage, and different fate associated with various stimuli contributions. Thus, in present study, we provide an overview for current knowledge of the phenotype of RAW264.7 cells, as well as the current understanding of the complicated interactions between various stimuli and RAW‐OCs in the light of the recent progress.
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Affiliation(s)
- Lingbo Kong
- Department of Spine, School of Medicine, Honghui-hospital, Xi'an Jiaotong University, Xi'an, China
| | - Wanli Smith
- Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland
| | - Dingjun Hao
- Department of Spine, School of Medicine, Honghui-hospital, Xi'an Jiaotong University, Xi'an, China
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5
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Wang Y, Galli M, Shade Silver A, Lee W, Song Y, Mei Y, Bachus C, Glogauer M, McCulloch CA. IL1β and TNFα promote RANKL-dependent adseverin expression and osteoclastogenesis. J Cell Sci 2018; 131:jcs.213967. [PMID: 29724913 DOI: 10.1242/jcs.213967] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/23/2018] [Indexed: 12/20/2022] Open
Abstract
Adseverin is an actin-binding protein involved in osteoclastogenesis, but its role in inflammation-induced bone loss is not well-defined. Here, we examined whether IL1β and TNFα regulate adseverin expression to control osteoclastogenesis in mouse primary monocytes and RAW264.7 cells. Adseverin was colocalized with subcortical actin filaments and was enriched in the fusopods of fusing cells. In precursor cells, adseverin overexpression boosted the formation of RANKL-induced multinucleated cells. Both IL1β and TNFα enhanced RANKL-dependent TRAcP activity by 1.6-fold and multinucleated cell formation (cells with ≥3 nuclei) by 2.6- and 3.3-fold, respectively. However, IL1β and TNFα did not enhance osteoclast formation in adseverin-knockdown cells. RANKL-dependent adseverin expression in bone marrow cells was increased by both IL1β (5.4-fold) and TNFα (3.3-fold). Luciferase assays demonstrated that this expression involved transcriptional regulation of the adseverin promoter. Activation of the promoter was restricted to a 1118 bp sequence containing an NF-κB binding site, upstream of the transcription start site. TNFα also promoted RANKL-induced osteoclast precursor cell migration. We conclude that IL1β and TNFα enhance RANKL-dependent expression of adseverin, which contributes to fusion processes in osteoclastogenesis.
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Affiliation(s)
- Yongqiang Wang
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada, M5S 3E2
| | - Matthew Galli
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada, M5S 3E2
| | - Alexandra Shade Silver
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada, M5S 3E2
| | - Wilson Lee
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada, M5S 3E2
| | - Yushan Song
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada, M5S 3E2
| | - Yixue Mei
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada, M5S 3E2
| | - Carly Bachus
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada, M5S 3E2
| | - Michael Glogauer
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada, M5S 3E2
| | - Christopher A McCulloch
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada, M5S 3E2
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6
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Tiedemann K, Le Nihouannen D, Fong JE, Hussein O, Barralet JE, Komarova SV. Regulation of Osteoclast Growth and Fusion by mTOR/raptor and mTOR/rictor/Akt. Front Cell Dev Biol 2017; 5:54. [PMID: 28573133 PMCID: PMC5435769 DOI: 10.3389/fcell.2017.00054] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/02/2017] [Indexed: 12/31/2022] Open
Abstract
Osteoclasts are giant bone cells formed by fusion from monocytes and uniquely capable of a complete destruction of mineralized tissues. Previously, we have demonstrated that in energy-rich environment not only osteoclast fusion index (the number of nuclei each osteoclast contains), but also cytoplasm volume per single nucleus was increased. The goal of this study was to investigate the regulation of metabolic sensor mTOR during osteoclast differentiation in energy-rich environment simulated by addition of pyruvate. We have found that in the presence of pyruvate, the proportion of mTOR associated with raptor increased, while mTOR-rictor-mediated Akt phosphorylation decreased. Inhibition of mTOR with rapamycin (10 nM) significantly interfered with all aspects of osteoclastogenesis. However, rapamycin at 1 nM, which preferentially targets mTOR-raptor complex, was only effective in control cultures, while in the presence of pyruvate osteoclast fusion index was successfully increased. Inhibition of Akt drastically reduced osteoclast fusion, however in energy-rich environment, osteoclasts of comparable size were formed through increased cytoplasm growth. These data suggest that mTOR-rictor mediated Akt signaling regulates osteoclast fusion, while mTOR-raptor regulation of protein translation contributes to fusion-independent cytoplasm growth. We demonstrate that depending on the bioenergetics microenvironment osteoclastogenesis can adjust to occur through preferential multinucleation or through cell growth, implying that attaining large cell size is part of the osteoclast differentiation program.
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Affiliation(s)
- Kerstin Tiedemann
- Faculty of Dentistry, McGill UniversityMontreal, QC, Canada.,Shriners Hospital for Children-CanadaMontreal, QC, Canada
| | | | - Jenna E Fong
- Faculty of Dentistry, McGill UniversityMontreal, QC, Canada
| | - Osama Hussein
- Faculty of Dentistry, McGill UniversityMontreal, QC, Canada
| | - Jake E Barralet
- Faculty of Dentistry, McGill UniversityMontreal, QC, Canada.,Department of Surgery, Faculty of Medicine, McGill UniversityMontreal, QC, Canada
| | - Svetlana V Komarova
- Faculty of Dentistry, McGill UniversityMontreal, QC, Canada.,Shriners Hospital for Children-CanadaMontreal, QC, Canada
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7
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Oliveira MC, Di Ceglie I, Arntz OJ, van den Berg WB, van den Hoogen FHJ, Ferreira AVM, van Lent PLEM, van de Loo FAJ. Milk-Derived Nanoparticle Fraction Promotes the Formation of Small Osteoclasts But Reduces Bone Resorption. J Cell Physiol 2016; 232:225-33. [PMID: 27138291 DOI: 10.1002/jcp.25414] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 04/29/2016] [Indexed: 01/15/2023]
Abstract
The general consensus is that milk promotes bone growth and density because is a source of calcium and contains components that enhance intestinal calcium uptake or directly affect bone metabolism. In this study, we investigated the effect of bovine-derived milk 100,000 g pellet (P100), which contains nanoparticles (<220 nm) including extracellular vesicles, on osteoclast differentiation and bone resorption. Bone marrow-derived osteoclast precursor cells were differentiated into osteoclasts by M-CSF and RANKL (control) and in the presence of milk P100. Milk P100 treatment until day 4 increased the number of TRAP-positive mononuclear cells and small (≤5 nuclei) osteoclasts. The number of large (≥6 nuclei) osteoclasts remained the same. These alterations were associated with increased expression of TRAP, NFATc1, and c-Fos. Cells seeded in a calcium-phosphate coated plate or bone slices showed reduced resorption area when exposed to milk P100 during the differentiation phase and even after osteoclast formation. Interestingly, milk P100 treatment enhanced Cathepsin K expression but reduced Carbonic Anhydrase 2 gene expression. Moreover, intracellular acid production was also decreased by milk P100 treatment. Oral delivery of milk P100 to female DBA1/J mice for 7 weeks did not alter bone area; however, increased osteoclast number and area in tibia without changes in serum RANKL and CTX-I levels. We showed for the first time the effect of milk P100 on osteoclast differentiation both in vitro and in vivo and found that milk P100 increased the formation of small osteoclasts but this does not lead to more bone resorption probably due to reduced acid secretion. J. Cell. Physiol. 232: 225-233, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Marina C Oliveira
- Experimental Rheumatology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Nutrition, Nursing School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Irene Di Ceglie
- Experimental Rheumatology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Onno J Arntz
- Experimental Rheumatology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Wim B van den Berg
- Experimental Rheumatology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Adaliene V M Ferreira
- Department of Nutrition, Nursing School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Peter L E M van Lent
- Experimental Rheumatology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Fons A J van de Loo
- Experimental Rheumatology, Radboud University Medical Center, Nijmegen, The Netherlands.
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8
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Morethson P. Extracellular fluid flow and chloride content modulate H(+) transport by osteoclasts. BMC Cell Biol 2015; 16:20. [PMID: 26271334 PMCID: PMC4536797 DOI: 10.1186/s12860-015-0066-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 07/28/2015] [Indexed: 11/18/2022] Open
Abstract
Background Bone resorption takes place within the basic multicellular units (BMU), and the surface to be resorbed is isolated from adjacent bone surfaces by a sealing zone between osteoclast membrane and bone matrix, which defines the limits of the resorption lacuna. Considering that the extracellular fluid (ECF) in both BMU and the resorption lacuna can be isolated from its surroundings, I hypothesize that flow and ion composition of the bone ECF in these sites might contribute to the regulation of osteoclast H+ secretion. To investigate this hypothesis, I evaluated the H+ secretion properties of individual osteoclasts and osteoclast-like cells (OCL-cells) and investigated whether changes in flow or chloride content of the extracellular solution modify the H+ secretion properties in vitro. Results The results show that 1) osteoclasts are unable to secrete H+ and regulate intracellular pH (pHi) under continuous flow conditions and exhibit progressive intracellular acidification; 2) the cessation of flow coincides with the onset of H+ secretion and subsequent progressive intracellular alkalinization of osteoclasts and OCL-cells; 3) osteoclasts exhibit spontaneous rhythmic oscillations of pHi in non-flowing ECF, 4) pHi oscillations are not abolished by concanamycin, NPPB, or removal of extracellular Na+ or Cl−; 5) extracellular Cl− removal modifies the pattern of oscillations, by diminishing H+ secretion; 6) pHi oscillations are abolished by continuous flowing of ECF over osteoclasts and OCL-cells. Conclusions The data suggest, for the first time, that ECF flow and Cl− content have direct effects on osteoclast H+ secretion and could be part of a mechanism determining the onset of osteoclast H+ secretion required for bone resorption. Electronic supplementary material The online version of this article (doi:10.1186/s12860-015-0066-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Priscilla Morethson
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil. .,Department of Biosciences, Federal University of São Paulo - Unifesp, R. Silva Jardim 136 Vila Mathias, Santos, 11065-201, SP, Brazil.
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9
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Role of actin filaments in fusopod formation and osteoclastogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1715-24. [DOI: 10.1016/j.bbamcr.2015.04.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/19/2015] [Accepted: 04/06/2015] [Indexed: 12/16/2022]
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10
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Mine Y, Shuto T, Nikawa H, Kawai T, Ohara M, Kawahara K, Ohta K, Kukita T, Terada Y, Makihira S. Inhibition of RANKL-dependent cellular fusion in pre-osteoclasts by amiloride and a NHE10-specific monoclonal antibody. Cell Biol Int 2015; 39:696-709. [PMID: 25612314 DOI: 10.1002/cbin.10447] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 01/09/2015] [Indexed: 11/05/2022]
Abstract
The functions of Na(+) /H(+) exchangers (NHEs) during osteoclastic differentiation were investigated using the NHE inhibitor amiloride and a monoclonal antibody (MAb). Compared with sRANKL-stimulated control cells, amiloride decreased the number of large TRAP-positive osteoclast cells (OCs) with ≥10 nuclei and increased the number of small TRAP-positive OCs with ≤10 nuclei during sRANKL-dependent osteoclastic differentiation of RAW264.7 cells. NHE10 mRNA expression and OC differentiation markers were increased by sRANKL stimulation in dose- and time-dependent manners. NHEs 1-9 mRNA expression was not increased by sRANKL stimulation. Similar to amiloride, a rat anti-mouse NHE10 MAb (clone 6B11) decreased the number of large TRAP-positive OCs, but increased the number of small TRAP-positive OCs. These findings suggested that inhibition of NHEs by amiloride or an anti-NHE10 MAb prevented sRANKL-promoted cellular fusion. The anti-NHE10 MAb has the potential for use as an effective inhibitor of bone resorption for targeted bone disease therapy.
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Affiliation(s)
- Yuichi Mine
- Department of Oral Biology and Engineering, Integrated Health Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi Minami-ku, Hiroshima, 734-8553, Japan
| | - Takahiro Shuto
- Section of Fixed Prosthodontics, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi Higashi-ku, Fukuoka, 812-8582, Japan
| | - Hiroki Nikawa
- Department of Oral Biology and Engineering, Integrated Health Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi Minami-ku, Hiroshima, 734-8553, Japan
| | - Toshihisa Kawai
- Department of Immunology and Infectious Diseases, The Forsyth Institute, 245 1st St., Cambridge, MA, 02142, USA.,Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, 188 Longwood Ave., Boston, MA, 02115,, USA
| | - Masaru Ohara
- Hiroshima University Hospital, Dental Clinic, 1-1-2 Kagamiyama, Higashihiroshima, 739-0046, Japan
| | - Kazuko Kawahara
- Department of Oral Biology and Engineering, Integrated Health Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi Minami-ku, Hiroshima, 734-8553, Japan
| | - Kouji Ohta
- Department of Immunology and Infectious Diseases, The Forsyth Institute, 245 1st St., Cambridge, MA, 02142, USA.,Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, 188 Longwood Ave., Boston, MA, 02115,, USA
| | - Toshio Kukita
- Department of Molecular Cell Biology and Oral Anatomy, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yoshihiro Terada
- Section of Fixed Prosthodontics, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi Higashi-ku, Fukuoka, 812-8582, Japan
| | - Seicho Makihira
- Section of Fixed Prosthodontics, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi Higashi-ku, Fukuoka, 812-8582, Japan
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11
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Faloni APDS, Sasso-Cerri E, Rocha FRG, Katchburian E, Cerri PS. Structural and functional changes in the alveolar bone osteoclasts of estrogen-treated rats. J Anat 2011; 220:77-85. [PMID: 22092353 DOI: 10.1111/j.1469-7580.2011.01449.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This study investigated structural and functional features of apoptotic alveolar bone osteoclasts in estrogen-treated rats. For this purpose, 15 female rats 22 days old were divided into three groups: Estrogen (EG), Sham (SG) and Control (CG). The rats of EG received daily intramuscular injection of estrogen for 7 days. The SG received only the oil vehicle. Maxillary fragments containing alveolar bone were removed and processed for light and transmission electron microscopy. Area (OcA) and number of nuclei (OcN) and bone resorption surface per TRAP-positive osteoclasts (BS/OC) were obtained. Vimentin, caspase-3 and MMP-9 immunoreactions, TUNEL/TRAP and MMP-9/TUNEL combined reactions were performed. In EG, the OcA, OcN and BS/Oc were reduced. Moreover, osteoclasts showed cytoplasm immunolabelled by caspase-3 and a different pattern of vimentin expression in comparison with CG and SG. MMP-9 expression was not affected by estrogen and the TUNEL-positive osteoclasts were MMP-9-immunolabelled. In EG, ultrastructural images showed that apoptotic osteoclasts did not exhibit ruffled borders or clear zones and were shedding mononucleated portions. TRAP-positive structures containing irregular and dense chromatin were partially surrounded by fibroblast-like cells. In conclusion, the reduction in the BS/Oc may be due to reduction in OcA and OcN; these effects seem to be related to vimentin disarrangement rather than to an interference of estrogen with osteoclast MMP-9 expression. Osteoclast apoptosis involves caspase-3 activity and vimentin degradation; these cells release portions containing one apoptotic nucleus and, subsequently, undergo fragmentation, giving rise to apoptotic bodies.
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12
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Makihira S, Nikawa H, Kajiya M, Kawai T, Mine Y, Kosaka E, Silva MJ, Tobiume K, Terada Y. Blocking of sodium and potassium ion-dependent adenosine triphosphatase-α1 with ouabain and vanadate suppresses cell–cell fusion during RANKL-mediated osteoclastogenesis. Eur J Pharmacol 2011; 670:409-18. [DOI: 10.1016/j.ejphar.2011.08.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 08/23/2011] [Accepted: 08/26/2011] [Indexed: 10/17/2022]
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13
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de Souza Faloni AP, Schoenmaker T, Azari A, Katchburian E, Cerri PS, de Vries TJ, Everts V. Jaw and long bone marrows have a different osteoclastogenic potential. Calcif Tissue Int 2011; 88:63-74. [PMID: 20862464 PMCID: PMC3021190 DOI: 10.1007/s00223-010-9418-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 08/28/2010] [Indexed: 11/29/2022]
Abstract
Osteoclasts, the multinucleated bone-resorbing cells, arise through fusion of precursors from the myeloid lineage. However, not all osteoclasts are alike; osteoclasts at different bone sites appear to differ in numerous respects. We investigated whether bone marrow cells obtained from jaw and long bone differed in their osteoclastogenic potential. Bone marrow cells from murine mandible and tibiae were isolated and cultured for 4 and 6 days on plastic or 6 and 10 days on dentin. Osteoclastogenesis was assessed by counting the number of TRAP(+) multinucleated cells. Bone marrow cell composition was analyzed by FACS. The expression of osteoclast- and osteoclastogenesis-related genes was studied by qPCR. TRAP activity and resorptive activity of osteoclasts were measured by absorbance and morphometric analyses, respectively. At day 4 more osteoclasts were formed in long bone cultures than in jaw cultures. At day 6 the difference in number was no longer observed. The jaw cultures, however, contained more large osteoclasts on plastic and on dentin. Long bone marrow contained more osteoclast precursors, in particular the myeloid blasts, and qPCR revealed that the RANKL:OPG ratio was higher in long bone cultures. TRAP expression was higher for the long bone cultures on dentin. Although jaw osteoclasts were larger than long bone osteoclasts, no differences were found between their resorptive activities. In conclusion, bone marrow cells from different skeletal locations (jaw and long bone) have different dynamics of osteoclastogenesis. We propose that this is primarily due to differences in the cellular composition of the bone site-specific marrow.
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Affiliation(s)
- Ana Paula de Souza Faloni
- Department of Morphology and Genetics, Federal University of São Paulo (UNIFESP), Rua Botucatu, 740 Vila Clementino, São Paulo, SP 04023-900 Brazil
- Department of Morphology, Dental School, Universidade Estadual Paulista (UNESP), Rua Humaitá 1680, Araraquara, SP 14801-903 Brazil
| | - Ton Schoenmaker
- Department of Oral Cell Biology and Periodontology, Academic Center of Dentistry Amsterdam (ACTA), Research Institute Move, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
| | - Azin Azari
- Department of Oral Cell Biology and Periodontology, Academic Center of Dentistry Amsterdam (ACTA), Research Institute Move, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
| | - Eduardo Katchburian
- Department of Morphology and Genetics, Federal University of São Paulo (UNIFESP), Rua Botucatu, 740 Vila Clementino, São Paulo, SP 04023-900 Brazil
| | - Paulo S. Cerri
- Department of Morphology, Dental School, Universidade Estadual Paulista (UNESP), Rua Humaitá 1680, Araraquara, SP 14801-903 Brazil
| | - Teun J. de Vries
- Department of Oral Cell Biology and Periodontology, Academic Center of Dentistry Amsterdam (ACTA), Research Institute Move, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
| | - Vincent Everts
- Department of Oral Cell Biology and Periodontology, Academic Center of Dentistry Amsterdam (ACTA), Research Institute Move, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
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14
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Wang Y, Grainger DW. siRNA knock-down of RANK signaling to control osteoclast-mediated bone resorption. Pharm Res 2010; 27:1273-84. [PMID: 20333451 PMCID: PMC2885461 DOI: 10.1007/s11095-010-0099-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 02/19/2010] [Indexed: 12/21/2022]
Abstract
PURPOSE To demonstrate the ability of small interfering (si)RNA targeting the cell receptor, RANK, to control osteoclast function in cultures of both primary and secondary osteoclasts and their precursor cells. METHODS siRNA targeting RANK was transfected into both RAW264.7 and primary bone marrow cell cultures. RANK knock-down by siRNA and functional inhibition were assessed in both mature osteoclast and their precursor cell cultures. RANK mRNA message and protein expression after the transfections were analyzed by PCR and Western blot, respectively. Off-target effects were assessed. The inhibition of osteoclast formation was evaluated using tartrate-resistant acid phosphatase (TRAP) assay, and subsequent bone resorption was determined by resorption pit assay. RESULTS Both osteoclasts and osteoclast precursors can be targeted by siRNA in serum-containing media. Delivery of siRNA targeting RANK to both RAW 264.7 and primary bone marrow cell cultures produces short term repression of RANK expression without off-targeting effects, and significantly inhibits both osteoclast formation and bone resorption. Moreover, data support successful RANK knock-down by siRNA specifically in mature osteoclast cultures. CONCLUSIONS RANK is demonstrated to be an attractive target for siRNA control of osteoclast activity, with utility for development of new therapeutics for low bone mass pathologies or osteoporosis.
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Affiliation(s)
- Yuwei Wang
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112-5820, USA.
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15
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Lau E, Al-Dujaili S, Guenther A, Liu D, Wang L, You L. Effect of low-magnitude, high-frequency vibration on osteocytes in the regulation of osteoclasts. Bone 2010; 46:1508-15. [PMID: 20211285 PMCID: PMC3084034 DOI: 10.1016/j.bone.2010.02.031] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/15/2010] [Accepted: 02/26/2010] [Indexed: 12/26/2022]
Abstract
Osteocytes are well evidenced to be the major mechanosensor in bone, responsible for sending signals to the effector cells (osteoblasts and osteoclasts) that carry out bone formation and resorption. Consistent with this hypothesis, it has been shown that osteocytes release various soluble factors (e.g. transforming growth factor-beta, nitric oxide, and prostaglandins) that influence osteoblastic and osteoclastic activities when subjected to a variety of mechanical stimuli, including fluid flow, hydrostatic pressure, and mechanical stretching. Recently, low-magnitude, high-frequency (LMHF) vibration (e.g., acceleration less than <1 x g, where g=9.81m/s(2), at 20-90 Hz) has gained much interest as studies have shown that such mechanical stimulation can positively influence skeletal homeostasis in animals and humans. Although the anabolic and anti-resorptive potential of LMHF vibration is becoming apparent, the signaling pathways that mediate bone adaptation to LMHF vibration are unknown. We hypothesize that osteocytes are the mechanosensor responsible for detecting the vibration stimulation and producing soluble factors that modulate the activity of effector cells. Hence, we applied low-magnitude (0.3 x g) vibrations to osteocyte-like MLO-Y4 cells at various frequencies (30, 60, 90 Hz) for 1h. We found that osteocytes were sensitive to this vibration stimulus at the transcriptional level: COX-2 maximally increased by 344% at 90Hz, while RANKL decreased most significantly (-55%, p<0.01) at 60Hz. Conditioned medium collected from the vibrated MLO-Y4 cells attenuated the formation of large osteoclasts (> or =10 nuclei) by 36% (p<0.05) and the amount of osteoclastic resorption by 20% (p=0.07). The amount of soluble RANKL (sRANKL) in the conditioned medium was found to be 53% lower in the vibrated group (p<0.01), while PGE(2) release was also significantly decreased (-61%, p<0.01). We conclude that osteocytes are able to sense LMHF vibration and respond by producing soluble factors that inhibit osteoclast formation.
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Affiliation(s)
- Esther Lau
- Institute of Biomaterials & Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Saja Al-Dujaili
- Institute of Biomaterials & Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Axel Guenther
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Dawei Liu
- Department of Developmental Sciences/Orthodontics, Marquette University School of Dentistry, Milwaukee, WI, USA
| | - Liyun Wang
- Center for Biomedical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Lidan You
- Institute of Biomaterials & Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
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16
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Gramoun A, Goto T, Nordström T, Rotstein OD, Grinstein S, Heersche JN, Manolson MF. Bone matrix proteins and extracellular acidification: Potential co-regulators of osteoclast morphology. J Cell Biochem 2010; 111:350-61. [DOI: 10.1002/jcb.22705] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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17
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Shen B, Ye CL, Ye KH, Zhuang L, Jiang JH. Doxorubicin-induced vasomotion and [Ca(2+)](i) elevation in vascular smooth muscle cells from C57BL/6 mice. Acta Pharmacol Sin 2009; 30:1488-95. [PMID: 19820720 PMCID: PMC4003006 DOI: 10.1038/aps.2009.145] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2009] [Accepted: 08/31/2009] [Indexed: 11/08/2022]
Abstract
AIM To explore the action of doxorubicin on vascular smooth muscle cells. METHODS Isometric tension of denuded or intact thoracic aortic vessels was recorded and [Ca(2+)](i) in isolated aortic smooth muscle cells was measured by using Fluo-3. RESULTS Doxorubicin induced phasic and tonic contractions in denuded vessels and increased levels of [Ca(2+)](i) in single muscle cells. Treatment with 10 micromol/L ryanodine had no effect on basal tension, but it did abolish doxorubicin-induced phasic contraction. Treatment with 10 mmol/L caffeine induced a transient phasic contraction only, and the effect was not significantly altered by ryanodine, the omission of extracellular Ca(2+) or both. Phenylephrine induced rhythmic contraction (RC) in intact vessels. Treatment with 100 micromol/L doxorubicin enhanced RC amplitude, but 1 mmol/L doxorubicin abolished RC, with an increase in maximal tension. Caffeine at 100 micromol/L increased the frequency of the RC only. In the presence of 100 micromol/L caffeine, however, 100 micromol/L doxorubicin abolished the RC and decreased its maximal tension. Treatment with 10 micromol/L ryanodine abolished the RC, with an increase in the maximal tension. In Ca(2+)-free solution, doxorubicin induced a transient [Ca(2+)](i) increase that could be abolished by ryanodine pretreatment in single muscle cells. The doxorubicin-induced increase in [Ca(2+)](i) was suppressed by nifedipine and potentiated by ryanodine and charybdotoxin. CONCLUSION Doxorubicin not only releases Ca(2+) from the sarcoplasmic reticulum but also promotes the entry of extracellular Ca(2+) into vascular smooth muscle cells.
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MESH Headings
- Aniline Compounds
- Animals
- Antibiotics, Antineoplastic/pharmacology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Calcium/metabolism
- Doxorubicin/pharmacology
- Fluorescent Dyes
- Isometric Contraction/drug effects
- Male
- Mice
- Mice, Inbred C57BL
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Sarcoplasmic Reticulum/drug effects
- Sarcoplasmic Reticulum/metabolism
- Xanthenes
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Affiliation(s)
- Bing Shen
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
- Department of Pharmacology, Anhui Medical University, Hefei 230022, China
| | - Chun-ling Ye
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
| | - Kai-he Ye
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
| | - Lan Zhuang
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
| | - Jia-hua Jiang
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
- Division of Cardiovascular Research, The Hospital for Sick Children, Toronto, Canada
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18
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Everts V, de Vries TJ, Helfrich MH. Osteoclast heterogeneity:. Biochim Biophys Acta Mol Basis Dis 2009; 1792:757-65. [DOI: 10.1016/j.bbadis.2009.05.004] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 05/15/2009] [Accepted: 05/18/2009] [Indexed: 01/11/2023]
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19
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Gramoun A, Shorey S, Bashutski JD, Dixon SJ, Sims SM, Heersche JNM, Manolson MF. Effects of Vitaxin, a novel therapeutic in trial for metastatic bone tumors, on osteoclast functions in vitro. J Cell Biochem 2008; 102:341-52. [PMID: 17390341 DOI: 10.1002/jcb.21296] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The integrin alphavbeta3 mediates cell-matrix interactions. Vitaxin(R), a humanized monoclonal antibody that blocks human and rabbit alphavbeta3 integrins, is in clinical trials for metastatic melanoma and prostate cancer. alphavbeta3 is the predominant integrin on osteoclasts, the cells responsible for bone resorption in health and disease. Here, we report the first investigation of Vitaxin's effects on osteoclast activity. Vitaxin (100-300 ng/ml) decreased total resorption by 50%, but did not alter resorptive activity per osteoclast. Vitaxin (300 ng/ml) decreased osteoclast numbers on plastic by 35% after 48 h. Similarly, attachment after 2 h was reduced by 30% when osteoclasts were incubated with Vitaxin (300 ng/ml) for 25 min prior to plating; however, the rate of fusion of osteoclast precursors in Vitaxin-treated and control groups was equal. Using time-lapse microscopy, we evaluated the effect of Vitaxin on osteoclast morphology and found a significant reduction in osteoclast planar area only when cells were pretreated with macrophage colony stimulating factor (M-CSF). Extracellular Ca(2+) and M-CSF have opposite effects on alphavbeta3 conformation. Elevation of extracellular Ca(2+) eliminated the inhibitory effect of Vitaxin on osteoclast attachment. In contrast, the effect of Vitaxin was enhanced in cells pretreated with M-CSF. This action of M-CSF was suppressed by the phosphatidylinositol 3-kinase (PI3-kinase) inhibitor wortmannin, suggesting that M-CSF increases Vitaxin's inhibitory effect by inside-out activation of alphavbeta3. In conclusion, Vitaxin decreases resorption by impairing osteoclast attachment, without affecting osteoclast formation and multinucleation. Our data also show that Vitaxin's inhibitory effects on osteoclasts can be modulated by factors known to alter the conformation of alphavbeta3.
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Affiliation(s)
- Azza Gramoun
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
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20
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Bouyer P, Sakai H, Itokawa T, Kawano T, Fulton CM, Boron WF, Insogna KL. Colony-stimulating factor-1 increases osteoclast intracellular pH and promotes survival via the electroneutral Na/HCO3 cotransporter NBCn1. Endocrinology 2007; 148:831-40. [PMID: 17068143 DOI: 10.1210/en.2006-0547] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Colony-stimulating factor-1 (CSF-1) promotes the survival of osteoclasts, short-lived cells that resorb bone. Although a rise in intracellular pH (pH(i)) has been linked to inhibition of apoptosis, the effect of CSF-1 on pH(i) in osteoclasts has not been reported. The present study shows that, in the absence of CO(2)/HCO(3)(-), CSF-1 causes little change in osteoclast pH(i). In contrast, exposing these cells to CSF-1 in the presence of CO(2)/HCO(3)(-) causes a rapid and sustained cellular alkalinization. The CSF-1-induced rise in pH(i) is not blocked by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, an inhibitor of HCO(3)(-) transporters but is abolished by removing extracellular sodium. This inhibition profile is similar to that of the electroneutral Na/HCO(3) cotransporter NBCn1. By RT-PCR, NBCn1 transcripts are present in both osteoclasts and osteoclast-like cells (OCLs), and by immunoblotting, the protein is present in OCLs. Moreover, CSF-1 promotes osteoclast survival in the presence of CO(2)/HCO(3)(-) buffer but not in its absence. Preventing the activation of NBCn1 markedly attenuates the ability of CSF-1 to 1) block activation of caspase-8 and 2) prolong osteoclast survival. Inhibiting caspase-3 or caspase-8 in OCLs prolongs osteoclast survival to the same extent as does CSF-1. This study provides the first evidence that osteoclasts express a CSF-1-regulated Na/HCO(3) cotransporter, which may play a role in cell survival.
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Affiliation(s)
- Patrice Bouyer
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, POB 208026, New Haven, Connecticut 06520-8026, USA.
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21
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Trebec DP, Chandra D, Gramoun A, Li K, Heersche JNM, Manolson MF. Increased expression of activating factors in large osteoclasts could explain their excessive activity in osteolytic diseases. J Cell Biochem 2007; 101:205-20. [PMID: 17216600 DOI: 10.1002/jcb.21171] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Large osteoclasts (>or=10 nuclei) predominate at sites of pathological bone resorption. We hypothesized this was related to increased resorptive activity of large osteoclasts and have demonstrated previously that larger osteoclasts are 8-fold more likely to be resorbing than small osteoclasts (2-5 nuclei). Here we ask whether these differences in resorptive activity can be explained by differences in expression of factors involved in osteoclast signaling, fusion, attachment, and matrix degradation. Authentic rabbit osteoclasts and osteoclasts derived from RAW264.7 cells showed similar increases in c-fms expression (1.7- to 1.8-fold) in large osteoclasts suggesting that RAW cells are a viable system for further analysis. We found 2- to 4.5-fold increases in the expression of the integrins alpha(v) and beta(3), the proteases proMMP9, matMMP9 and pro-cathepsinK, and in activating receptors RANK, IL-1R1, and TNFR1 in large osteoclasts. In contrast, small osteoclasts had higher expression of the fusion protein SIRPalpha1 and the decoy receptor IL-1R2. The higher expression of activation receptors and lower expression of IL-1R2 in large osteoclasts suggest they are hyperresponsive to extracellular factors. This is supported by the observation that the resorptive activity in large osteoclasts was more responsive to IL-1beta, and that this increased activity was inhibited by the IL-1 receptor antagonist, IL-1ra. This increased responsiveness of large osteoclasts to IL-1 may, in part, explain the pathological bone loss noted in inflammatory diseases. The heterogeneity in receptor expression and the differential response to cytokines and their antagonists could prove useful for selective inhibition of large osteoclasts actively engaged in pathological bone loss.
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Affiliation(s)
- Diana P Trebec
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
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22
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Pyza E, Borycz J, Giebultowicz JM, Meinertzhagen IA. Involvement of V-ATPase in the regulation of cell size in the fly's visual system. JOURNAL OF INSECT PHYSIOLOGY 2004; 50:985-994. [PMID: 15607501 DOI: 10.1016/j.jinsphys.2004.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2003] [Revised: 08/06/2004] [Accepted: 08/06/2004] [Indexed: 05/24/2023]
Abstract
In the fly's visual system, two classes of lamina interneuron, L1 and L2, cyclically change both their size and shape in a rhythm that is circadian. Several neurotransmitters and the lamina's glial cells are known to be involved in regulating these rhythms. Moreover, vacuolar-type H+-ATPase (V-ATPase) in the optic lobe is thought also to participate in such regulation. We have detected V-ATPase-like immunoreactivity in the heads of both Drosophilla melanogaster and Musca domestica using antibodies raised against either the B- or H-subunits of V-ATPase from D. melanogaster or against the B-subunit from two other insect species Culex quinquefasciatus and Manduca sexta. In the visual systems of both fly species V-ATPase was localized immunocytochemically to the compound eye photoreceptors. In D. melanogaster immunoreactivity oscillated during the day and night and under constant darkness the signal was stronger during the subjective night than the subjective day. In turn, blocking V-ATPase by injecting a V-ATPase blocker, bafilomycin, in M. domestica increased the axon sizes of L1 and L2, but only when bafilomycin was applied during the night. As a result bafilomycin abolished the day/night difference in axon size in L1 and L2, their sizes being similar during the day and night.
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Affiliation(s)
- E Pyza
- Department of Cytology and Histology, Institute of Zoology, Jagiellonian University, Ingardena 6, 30-060 Kraków, Poland.
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23
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Mori H, Sakai H, Morihata H, Kawawaki J, Amano H, Yamano T, Kuno M. Regulatory mechanisms and physiological relevance of a voltage-gated H+ channel in murine osteoclasts: phorbol myristate acetate induces cell acidosis and the channel activation. J Bone Miner Res 2003; 18:2069-76. [PMID: 14606521 DOI: 10.1359/jbmr.2003.18.11.2069] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED The voltage-gated H+ channel is a powerful H+ extruding mechanism of osteoclasts, but its functional roles and regulatory mechanisms remain unclear. Electrophysiological recordings revealed that the H+ channel operated on activation of protein kinase C together with cell acidosis. INTRODUCTION H+ is a key signaling ion in bone resorption. In addition to H+ pumps and exchangers, osteoclasts are equipped with H+ conductive pathways to compensate rapidly for pH imbalance. The H+ channel is distinct in its strong H+ extrusion ability and voltage-dependent gatings. METHODS To investigate how and when the H+ channel is available in functional osteoclasts, the effects of phorbol 12-myristate 13-acetate (PMA), an activator for protein kinase C, on the H+ channel were examined in murine osteoclasts generated in the presence of soluble RANKL (sRANKL) and macrophage-colony stimulating factor (M-CSF). RESULTS AND CONCLUSIONS Whole cell recordings clearly showed that the H+ current was enhanced by increasing the pH gradient across the plasma membrane (delta(pH)), indicating that the H+ channel changed its activity by sensing delta(pH). The reversal potential (V(rev)) was a valuable tool for the real-time monitoring of delta(pH) in clamped cells. In the permeabilized patch, PMA (10 nM-1.6 microM) increased the current density and the activation rate, slowed decay of tail currents, and shifted the threshold toward more negative voltages. In addition, PMA caused a negative shift of V(rev), suggesting that intracellular acidification occurred. The PMA-induced cell acidosis was confirmed using a fluorescent pH indicator (BCECF), which recovered quickly in a K(+)-rich alkaline solution, probably through the activated H+ channel. Both cell acidosis and activation of the H+ channel by PMA were inhibited by staurosporine. In approximately 80% of cells, the PMA-induced augmentation in the current activity remained after compensating for the delta(pH) changes, implying that both delta(pH)-dependent and -independent mechanisms mediated the channel activation. Activation of the H+ channel shifted the membrane potential toward V(rev). These data suggest that the H+ channel may contribute to regulation of the pH environments and the membrane potential in osteoclasts activated by protein kinase C.
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Affiliation(s)
- Hiroyuki Mori
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka, Japan
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24
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Manolson MF, Yu H, Chen W, Yao Y, Li K, Lees RL, Heersche JNM. The a3 isoform of the 100-kDa V-ATPase subunit is highly but differentially expressed in large (>or=10 nuclei) and small (<or= nuclei) osteoclasts. J Biol Chem 2003; 278:49271-8. [PMID: 14504271 DOI: 10.1074/jbc.m309914200] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Osteoclasts dissolve bone through acidification of an extracellular compartment by means of a multimeric vacuolar type H+-ATPase (V-ATPase). In mammals, there are four isoforms of the 100-kDa V-ATPase "a" subunit. Mutations in the a3 isoform result in deficient bone resorption and osteopetrosis, suggesting that a3 has a unique function in osteoclasts. It is thus surprising that several studies show a basal level of a3 expression in most tissues. To address this issue, we have compared a3 expression in bone with expression in other tissues. RNA blots revealed that the a3 isoform was expressed highest in bone and confirmed its expression (in decreasing order) in liver, kidney, brain, lung, spleen, and muscle. In situ hybridization on bone tissue sections revealed that the a3 isoform was highly expressed in multinucleated osteoclasts but not in mononuclear stromal cells, whereas the a1 isoform was expressed in both cell types at about the same level. We also found that a3 expression was greater in osteoclasts with 10 or more nuclei as compared with osteoclasts with five or fewer nuclei. We hypothesize that these differences in a3 expression may be associated with previously demonstrated differences between large and small osteoclasts with reference to their resorptive activity.
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Affiliation(s)
- Morris F Manolson
- Faculty of Dentistry, University of Toronto, Toronto, Ontario M5G 1G6, Canada.
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25
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Abstract
Osteoclasts resorb bone by attaching to the surface and then secreting protons into an extracellular compartment formed between osteoclast and bone surface. This secretion is necessary for bone mineral solubilization and the digestion of organic bone matrix by acid proteases. This study summarizes the characterization and role of each type of ion transport and defines the main biochemical mechanisms involved in the dissolution of bone mineral during bone resorption. The primary mechanism responsible for acidification of the osteoclast-bone interface is vacuolar H+-adenosine triphosphatase (ATPase) coupled with Cl- conductance localized to the ruffled membrane. Carbonic anhydrase II (CAII) provides the proton source for extracellular acidification by H+-ATPase and the HCO3- source for the HCO3-/Cl- exchanger. Whereas some transporters are responsible for the bone resorption process, others are essential for pH regulation in the osteoclast. The HCO3-/Cl- exchanger, in association with CAII, is the major transporter for maintenance of normal intracellular pH. An Na+/H+ antiporter may also contribute to the recovery of intracellular pH during early osteoclast activation. Once this mechanism has been rendered inoperative, another conductive pathway translocates the protons and modulates cytoplasmic pH. Inward-rectifying K+ channels may also be involved by compensating for the external acidification due to H+ transport. These different effects of transport processes, either on bone resorption or pH homeostasis, increase the number of possible sites for pharmacological intervention in the treatment of metabolic bone diseases.
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Affiliation(s)
- A-V Rousselle
- Labaoratoire de Physiopathologie de la Résorption Osseuse, Faculté de Médecine, Nantes, France
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27
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Lees RL, Sabharwal VK, Heersche JN. Resorptive state and cell size influence intracellular pH regulation in rabbit osteoclasts cultured on collagen-hydroxyapatite films. Bone 2001; 28:187-94. [PMID: 11182377 DOI: 10.1016/s8756-3282(00)00433-6] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Diseases exhibiting excessive bone loss are often characterized by an increase in the size and number of osteoclasts in affected areas, suggesting that osteoclast size is associated with increased resorptive activity or efficiency. Because osteoclastic bone resorption depends on proton extrusion via a bafilomycin A1-sensitive vacuolar type H+ ATPase (V-ATPase), we investigated the relationship between osteoclast size and state of activity on the one hand, and proton-extruding mechanisms (bafilomycin A1-sensitive V-ATPase and amiloride-sensitive Na+/H+ exchange) on the other. In determining resorptive activities of individual osteoclasts, osteoclast-containing cell suspensions obtained from newborn rabbit long bones were cultured on apatite-collagen complex (ACC)-coated coverslips. Large osteoclasts resorbed 2.5 times more per cell than small osteoclasts, but the amount resorbed per nucleus was the same for the two categories. However, a much larger percentage of large osteoclasts was resorbing compared with small osteoclasts. To study pH regulatory mechanisms in individual large and small osteoclasts, the cells were loaded with the pH-sensitive indicator BCECF and analyzed by single-cell fluorescence. Small and large resorbing osteoclasts had significantly higher basal pH(i) than their nonresorbing counterparts. Also, small nonresorbing osteoclasts were insensitive to bafilomycin A1 addition or Na+ removal from the medium, large nonresorbing osteoclasts responded slightly, and all resorbing osteoclasts (small and large) responded strongly. Differences were also seen in the recovery from an acid load: both small and large nonresorbing osteoclasts were more sensitive to amiloride inhibition, while large resorbing cells were more sensitive to bafilomycin A1 inhibition. Small resorbing cells were inhibited equally by bafilomycin A1 and amiloride. These results clearly show that a greater proportion of large osteoclasts are active in resorption and that pH(i) regulation is associated with enhanced proton pump activity in actively resorbing osteoclasts. Thus, large and small osteoclasts differ in the proportion of cells that are resorbing, while pH regulatory mechanisms differ mainly between resorbing and nonresorbing cells.
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Affiliation(s)
- R L Lees
- Department of Pharmacology, Faculty of Medicine, Toronto, Ontario, Canada
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