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Kobayashi Y, Quispe-Salcedo A, Bodas S, Matsumura S, Li E, Johnson R, Choudhury M, Fine DH, Nadimpalli S, Duncan HF, Dudakovic A, van Wijnen AJ, Shimizu E. Ezh2 knockout in mesenchymal cells causes enamel hyper-mineralization. Biochem Biophys Res Commun 2021; 567:72-78. [PMID: 34144503 DOI: 10.1016/j.bbrc.2021.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/01/2021] [Indexed: 11/29/2022]
Abstract
Enhancer of zeste homolog 2 (EZH2) is the catalytic core of polycomb repressive complex 2 (PRC2), which primarily methylates lysine 27 on histone H3 (H2K27me3), generating transcriptionally suppressed heterochromatin. Since EZH2 suppresses expression of genes involved in dentin formation, we examined the role of EZH2 in tooth development. Intriguingly, microCT analysis of teeth from mice with conditional Ezh2 knockout in uncommitted mesenchymal cells showed hyper-mineralization of enamel, which is produced by the epithelial-lineage cells, ameloblasts. Scanning electron microscopy analysis and nano-indentation of the incisor enamel from knockout mice revealed smaller inter-rod spaces and higher hardness compared to wild type enamel, respectively. Interestingly, expression of the calcium channel subunit gene, Orai2, was decreased compared to its competitor, Orai1, both in knockout mouse incisors and the ex vivo culture of ameloblasts with the surrounding tissues under EZH2 inhibition. Moreover, histological analysis of incisor from knockout mice showed decreased ameloblastin and expedited KLK4 expression in the ameloblasts. These observations suggest that EZH2 depletion in dental mesenchymal cells reduces enamel matrix formation and increases enamel protease activity from ameloblasts, resulting in enamel hyper-mineralization. This study demonstrates the significant role of the suppressive H3K27me3 mark for heterochromatin on enamel formation.
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Affiliation(s)
| | | | - Sanika Bodas
- Department of Oral Biology, Rutgers School of Dental Medicine, NJ, USA
| | | | - Erhao Li
- Frontage Laboratories, Inc, PA, USA
| | - Richard Johnson
- Department of Mechanical and Industrial Engineering, New Jersey Institute of Technology, NJ, USA
| | - Marwa Choudhury
- Department of Oral Biology, Rutgers School of Dental Medicine, NJ, USA
| | - Daniel H Fine
- Department of Oral Biology, Rutgers School of Dental Medicine, NJ, USA
| | - Siva Nadimpalli
- Department of Mechanical Engineering, Michigan State University, MI, USA
| | - Henry F Duncan
- Division of Restorative Dentistry & Periodontology, Dublin Dental University Hospital, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland
| | - Amel Dudakovic
- Departments of Orthopedic Surgery and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Andre J van Wijnen
- Departments of Orthopedic Surgery and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.
| | - Emi Shimizu
- Department of Oral Biology, Rutgers School of Dental Medicine, NJ, USA.
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Gama A, Vargas-Franco JW, Sánchez Mesa DC, Restrepo Bedoya E, Amiaud J, Babajko S, Berdal A, Acevedo AC, Heymann D, Lézot F, Castaneda B. Origins of Alterations to Rankl Null Mutant Mouse Dental Root Development. Int J Mol Sci 2020; 21:ijms21062201. [PMID: 32209985 PMCID: PMC7139335 DOI: 10.3390/ijms21062201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 02/07/2023] Open
Abstract
The purpose of the present study was to assess the early stages of development of mouse first molar roots in the osteopetrotic context of RANKL invalidation in order to demonstrate that the radicular phenotype observed resulted not only from defective osteoclasts, but also from loss of cell-to-cell communication among dental, periodontium and alveolar bone cells involving RANKL signaling. Two experimental models were used in this study: Rankl mutants with permanent RANKL invalidation, and C57BL/6J mice injected during the first postnatal week with a RANKL neutralizing antibody corresponding to a transient RANKL invalidation. The dento-alveolar complex was systematically analyzed using micro-CT, and histological and immunohistochemical approaches. These experiments showed that the root elongation alterations observed in the Rankl-/- mice were associated with reduced proliferation of the RANK-expressing HERS cells with a significant decrease in proliferating cell nuclear antigen (PCNA) expression and a significant increase in P21 expression. The phenotypic comparison of the adult first molar root at 35 days between permanent and transitory invalidations of RANKL made it possible to demonstrate that alterations in dental root development have at least two origins, one intrinsic and linked to proliferation/differentiation perturbations in dental-root-forming cells, the other extrinsic and corresponding to disturbances of bone cell differentiation/function.
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Affiliation(s)
- Andrea Gama
- Centre de Recherche des Cordeliers, INSERM UMR-1138, Sorbonne Université, Université de Paris, Laboratoire de Physiopathologie Orale Moléculaire, F-75006 Paris, France; (A.G.); (D.C.S.M.); (E.R.B.); (S.B.); (A.B.)
- Odontologic Center of District Federal Military Police, Brasília 70297-400, Brazil
- Laboratory of Oral Histopathology, Health Sciences Faculty, University of Brasília, Brasília 70910-900, Brazil;
| | - Jorge William Vargas-Franco
- INSERM, UMR-1238, Equipe 1, Faculté de Médecine, Université de Nantes, F-44035 Nantes, France; (J.W.V.-F.); (J.A.); (F.L.)
- Department of Basic Studies, Faculty of Odontology, University of Antioquia, Medellin A.A1226, Colombia
| | - Diana Carolina Sánchez Mesa
- Centre de Recherche des Cordeliers, INSERM UMR-1138, Sorbonne Université, Université de Paris, Laboratoire de Physiopathologie Orale Moléculaire, F-75006 Paris, France; (A.G.); (D.C.S.M.); (E.R.B.); (S.B.); (A.B.)
- Department of Orthodontics, Faculty of Odontology, University of Antioquia, Medellin A.A1226, Colombia
| | - Elizabeth Restrepo Bedoya
- Centre de Recherche des Cordeliers, INSERM UMR-1138, Sorbonne Université, Université de Paris, Laboratoire de Physiopathologie Orale Moléculaire, F-75006 Paris, France; (A.G.); (D.C.S.M.); (E.R.B.); (S.B.); (A.B.)
- Department of Orthodontics, Faculty of Odontology, University of Antioquia, Medellin A.A1226, Colombia
| | - Jérome Amiaud
- INSERM, UMR-1238, Equipe 1, Faculté de Médecine, Université de Nantes, F-44035 Nantes, France; (J.W.V.-F.); (J.A.); (F.L.)
| | - Sylvie Babajko
- Centre de Recherche des Cordeliers, INSERM UMR-1138, Sorbonne Université, Université de Paris, Laboratoire de Physiopathologie Orale Moléculaire, F-75006 Paris, France; (A.G.); (D.C.S.M.); (E.R.B.); (S.B.); (A.B.)
| | - Ariane Berdal
- Centre de Recherche des Cordeliers, INSERM UMR-1138, Sorbonne Université, Université de Paris, Laboratoire de Physiopathologie Orale Moléculaire, F-75006 Paris, France; (A.G.); (D.C.S.M.); (E.R.B.); (S.B.); (A.B.)
| | - Ana Carolina Acevedo
- Laboratory of Oral Histopathology, Health Sciences Faculty, University of Brasília, Brasília 70910-900, Brazil;
- Oral Center for Inherited Diseases, Hospital of University of Brasilia, University of Brasília, Brasília 70910-900, Brazil
| | - Dominique Heymann
- INSERM, LEA Sarcoma Research Unit, University of Sheffield, Department of Oncology and Human Metabolism, Medical School, Sheffield S10 2RX, UK;
- INSERM, UMR-1232, LabCT, CRCNA, Université de Nantes, Université d’Angers, Institut de Cancérologie de l’Ouest, site René Gauducheau, F-44805 Saint-Herblain, France
| | - Frédéric Lézot
- INSERM, UMR-1238, Equipe 1, Faculté de Médecine, Université de Nantes, F-44035 Nantes, France; (J.W.V.-F.); (J.A.); (F.L.)
| | - Beatriz Castaneda
- Service d’Odontologie-Stomatologie, Hôpital Pitié-Salpêtrière, AP-HP, F-75013 Paris, France
- Correspondence: ; Tel.: +33-142-178-416
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Gao X, Zheng J, Tu S, Cai B, Zeng R, Xiang L. Role of osteoprotegerin in the regulation of dental epithelial‑mesenchymal signaling during tooth development. Mol Med Rep 2019; 20:3035-3042. [PMID: 31432164 PMCID: PMC6755199 DOI: 10.3892/mmr.2019.10567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/24/2019] [Indexed: 12/16/2022] Open
Abstract
Dental epithelial-mesenchymal signaling is crucial for tooth development, but the detailed mechanism is not fully understood. Using microarray analysis, it was revealed that the expression of osteoprotegerin, an important factor regulating bone remodeling, significantly increased after removal of the dental epithelium. Immunohistochemical staining revealed that osteoprotegerin expression within the dental mesenchyme was quite low during the prenatal period, but significantly increased after birth. To investigate the influence of osteoprotegerin upon tooth development, first-molar tooth germs from embryonic day 14.5 (E14.5) Chinese Kunming mice were treated with different concentrations of osteoprotegerin. It was revealed that osteoprotegerin could inhibit the expression of odontogenic markers while promoting the expression of osteogenic markers, thereby disrupting tooth morphogenesis. These findings were further supported by in vitro and in vivo cultures. Finally, quantitative reverse transcription-polymerase chain reaction and immunofluorescence studies revealed that, after osteoprotegerin treatment, the activity of the wingless/integrated (Wnt)/β-catenin pathway increased, indicating that increased osteoprotegerin expression in prenatal tooth development could lead to uncontrolled upregulation of the Wnt/β-catenin pathway.
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Affiliation(s)
- Xin Gao
- Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China
| | - Junming Zheng
- Research Management Office, Foshan Stomatology Hospital, School of Stomatology and Medicine, Foshan University, Foshan, Guangdong 528000, P.R. China
| | - Shaoqin Tu
- Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China
| | - Bin Cai
- Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China
| | - Rongsheng Zeng
- Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China
| | - Lusai Xiang
- Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China
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Vargas-Franco JW, Castaneda B, Gama A, Mueller CG, Heymann D, Rédini F, Lézot F. Genetically-achieved disturbances to the expression levels of TNFSF11 receptors modulate the effects of zoledronic acid on growing mouse skeletons. Biochem Pharmacol 2019; 168:133-148. [PMID: 31260659 DOI: 10.1016/j.bcp.2019.06.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Accepted: 06/26/2019] [Indexed: 01/17/2023]
Abstract
Zoledronic acid (ZOL), a nitrogen bisphosphonate (N-BP), is currently used to treat and control pediatric osteolytic diseases. Variations in the intensity of the effects and side effects of N-BPs have been reported with no clear explanations regarding their origins. We wonder if such variations could be associated with different levels of RANKL signaling activity in growing bone during and after the treatment with N-BPs. To answer this question, ZOL was injected into neonate C57BL/6J mice with different genetically-determined RANKL signaling activity levels (Opg+/+\RankTg-, Opg+/+\RankTg+, Opg+/-\RankTg-, Opg+/-\RankTg+, Opg-/-\RankTg- and Opg-/-\RankTg+ mice) following a protocol (4 injections from post-natal day 1 to 7 at the dose of 50 μg/kg) that mimics those used in onco-pediatric patients. At the end of pediatric growth (1 and half months) and at an adult age (10 months), the bone morphometric and mineral parameters were measured using μCT in the tibia and skull for the different mice. A histologic analysis of the dental and periodontal tissues was also performed. At the end of pediatric growth, a delay in long bone and skull bone growth, a blockage of tooth eruption, some molar root alterations and a neoplasia-like structure associated with incisor development were found. Interestingly, the magnitude of these side effects was reduced by Opg deficiency (Opg-/-) but increased by Rank overexpression (RankTg). Analysis of the skeletal phenotype at ten months confirmed respectively the beneficial and harmful effects of Opg deficiency and Rank overexpression. These results validated the hypothesis that the RANKL signaling activity level in the bone microenvironment is implicated in the modulation of the response to ZOL. Further studies will be necessary to understand the underlying molecular mechanisms, which will help decipher the variability in the effects of N-BPs reported in the human population. SIGNIFICANT STATEMENTS: The present study establishes that in mice the RANKL signaling activity level is a major modulator of the effects and side-effects of bisphosphonates on the individual skeleton during growth. However, the modulatory actions are dependent on the ways in which this level of activity is increased. A decrease in OPG expression is beneficial to the skeletal phenotype observed at the end of growth, while RANK overexpression deteriorates it. Far removed from pediatric treatment, in adults, the skeletal phenotypes initially observed at the end of growth for the different levels of RANKL signaling activity were maintained, although significant improvement was associated only with reductions in OPG expression.
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Affiliation(s)
- Jorge William Vargas-Franco
- INSERM, UMR-1238, Equipe 1, Faculté de Médecine, Université de Nantes, Nantes F-44035, France; Department of Basic Studies, Faculty of Odontology, University of Antioquia, Medellin, Colombia
| | - Beatriz Castaneda
- Service d'Odontologie-Stomatologie, Hôpital Pitié-Salpêtrière, AP-HP, Paris F-75013, France
| | - Andrea Gama
- INSERM, UMR-1138, Equipe 5, Centre de Recherche des Cordeliers, Paris F-75006, France; Odontology Center of District Federal Military Police, Brasília, Brazil; Oral Histopathology Laboratory, Health Sciences Faculty, University of Brasília, Brasília, Brazil
| | - Christopher G Mueller
- CNRS, UPR 9021, Institut de Biologie Moléculaire et Cellulaire (IBMC), Laboratoire Immunologie et Chimie Thérapeutiques, Université de Strasbourg, Strasbourg F-67084, France
| | - Dominique Heymann
- INSERM, LEA Sarcoma Research Unit, University of Sheffield, Department of Oncology and Human Metabolism, Medical School, Sheffield S10 2RX, UK; INSERM, UMR 1232, LabCT, Université de Nantes, Université d'Angers, Institut de Cancérologie de l'Ouest, site René Gauducheau, Saint-Herblain F-44805, France
| | - Françoise Rédini
- INSERM, UMR-1238, Equipe 1, Faculté de Médecine, Université de Nantes, Nantes F-44035, France
| | - Frédéric Lézot
- INSERM, UMR-1238, Equipe 1, Faculté de Médecine, Université de Nantes, Nantes F-44035, France.
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5
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Soenjaya Y, Foster BL, Nociti FH, Ao M, Holdsworth DW, Hunter GK, Somerman MJ, Goldberg HA. Mechanical Forces Exacerbate Periodontal Defects in Bsp-null Mice. J Dent Res 2015; 94:1276-85. [PMID: 26130257 DOI: 10.1177/0022034515592581] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Bone sialoprotein (BSP) is an acidic phosphoprotein with collagen-binding, cell attachment, and hydroxyapatite-nucleating properties. BSP expression in mineralized tissues is upregulated at onset of mineralization. Bsp-null (Bsp(-/-)) mice exhibit reductions in bone mineral density, bone turnover, osteoclast activation, and impaired bone healing. Furthermore, Bsp(-/-) mice have marked periodontal tissue breakdown, with a lack of acellular cementum leading to periodontal ligament detachment, extensive alveolar bone and tooth root resorption, and incisor malocclusion. We hypothesized that altered mechanical stress from mastication contributes to periodontal destruction observed in Bsp(-/-) mice. This hypothesis was tested by comparing Bsp(-/-) and wild-type mice fed with standard hard pellet diet or soft powder diet. Dentoalveolar tissues were analyzed using histology and micro-computed tomography. By 8 wk of age, Bsp(-/-) mice exhibited molar and incisor malocclusion regardless of diet. Bsp(-/-) mice with hard pellet diet exhibited high incidence (30%) of severe incisor malocclusion, 10% lower body weight, 3% reduced femur length, and 30% elevated serum alkaline phosphatase activity compared to wild type. Soft powder diet reduced severe incisor malocclusion incidence to 3% in Bsp(-/-) mice, supporting the hypothesis that occlusal loading contributed to the malocclusion phenotype. Furthermore, Bsp(-/-) mice in the soft powder diet group featured normal body weight, long bone length, and serum alkaline phosphatase activity, suggesting that tooth dysfunction and malnutrition contribute to growth and skeletal defects reported in Bsp(-/-) mice. Bsp(-/-) incisors also erupt at a slower rate, which likely leads to the observed thickened dentin and enhanced mineralization of dentin and enamel toward the apical end. We propose that the decrease in eruption rate is due to a lack of acellular cementum and associated defective periodontal attachment. These data demonstrate the importance of BSP in maintaining proper periodontal function and alveolar bone remodeling and point to dental dysfunction as causative factor of skeletal defects observed in Bsp(-/-) mice.
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Affiliation(s)
- Y Soenjaya
- Biomedical Engineering Program, University of Western Ontario, London, Canada School of Dentistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada
| | - B L Foster
- National Institute for Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - F H Nociti
- National Institute for Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA Department of Prosthodontics and Periodontics, Division of Periodontics, School of Dentistry, Campinas State University, Piracicaba, Brazil
| | - M Ao
- National Institute for Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - D W Holdsworth
- Biomedical Engineering Program, University of Western Ontario, London, Canada School of Dentistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Canada
| | - G K Hunter
- Biomedical Engineering Program, University of Western Ontario, London, Canada School of Dentistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada Deparment of Biochemistry, University of Western Ontario, London, Canada
| | - M J Somerman
- National Institute for Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - H A Goldberg
- Biomedical Engineering Program, University of Western Ontario, London, Canada School of Dentistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada Deparment of Biochemistry, University of Western Ontario, London, Canada
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Diabetes detrimental effects on enamel and dentine formation. J Dent 2015; 43:589-96. [PMID: 25681642 DOI: 10.1016/j.jdent.2015.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/28/2014] [Accepted: 01/15/2015] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES Understanding morphological changes and mineral content of tooth hard tissues may influence dental treatment. In this study, the effect of Type 1 Diabetes Mellitus (T1DM) on tooth structure was examined. METHODS Experimental T1DM was induced in 3-week old male Wistar rats (n=10) by a single dose of 60mg/kg body weight of Streprozotocin. All rats were injected with calcein twice during the experiment and sacrificed at the age of 7 weeks old. Micro-computed tomography (micro-CT) was used to determine the mineral density and thickness of enamel and dentine. Also, a histomorphometery study was conducted to detect the rates of dentine mineral apposition and formation. The examined area was in the crown analogue of the rat mandibular incisor parallel to the long axis of the mesial surface of the first molar. All results were compared using Students' t-test (p<0.05). RESULTS Results showed that the enamel and dentine thickness were significantly reduced (hypoplasia) and there was a significant reduction of the rate of dentine mineral apposition and formation, while there was no significant effect of the T1DM condition on the mineral density of enamel and dentine. CONCLUSIONS T1DM has a detrimental influence on the formation of enamel and dentine in the early growth stage. CLINICAL SIGNIFICANCE T1DM condition may alter treatment planning of orthodontic treatment as it is associated with decreased enamel and dentin thickness that may affect teeth size and their resistance to caries.
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Gronowicz G, Richardson YL, Flynn J, Kveton J, Eisen M, Leonard G, Aronow M, Rodner C, Parham K. Differences in Otosclerotic and Normal Human Stapedial Osteoblast Properties Are Normalized by Alendronate in Vitro. Otolaryngol Head Neck Surg 2014; 151:657-66. [DOI: 10.1177/0194599814544889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Objective Identify and compare phenotypic properties of osteoblasts from patients with otosclerosis (OSO), normal bones (HOB), and normal stapes (NSO) to determine a possible cause for OSO hypermineralization and assess any effects of the bisphosphonate, alendronate. Study Design OSO (n = 11), NSO (n = 4), and HOB (n = 13) cultures were assayed for proliferation, adhesion, mineralization, and gene expression with and without 10–10M-10–8M alendronate. Setting Academic hospital. Methods Cultures were matched for age, sex, and passage number. Cell attachment and proliferation + alendronate were determined by Coulter counting cells and assaying tritiated thymidine uptake, respectively. At 7, 14, and 21 days of culture + alendronate, calcium content and gene expression by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were determined. Results OSO had significantly more cells adhere but less proliferation than NSO or HOB. Calcification was significantly increased in OSO compared to HOB and NSO. NSO and HOB had similar cell adhesion and proliferation rates. A dose-dependent effect of alendronate on OSO adhesion, proliferation, and mineralization was found, resulting in levels equal to NSO and HOB. All cultures expressed osteoblast-specific genes such as RUNX2, alkaline phosphatase, type I collagen, and osteocalcin. However, osteopontin was dramatically reduced, 9.4-fold at 14 days, in OSO compared to NSO. Receptor activator of nuclear factor κB ligand/osteoprotegerin (RANKL/OPG), important in bone resorption, was elevated in OSO with decreased levels of OPG levels. Alendronate had little effect on gene expression in HOB but in OSO increased osteopontin levels and decreased RANKL/OPG. Conclusions OSO cultures displayed properties of hypermineralization due to decreased osteopontin (OPN) and also had increased RANKL/OPG, which were normalized by alendronate.
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Affiliation(s)
- Gloria Gronowicz
- University of Connecticut Health Center, Farmington, Connecticut, USA
| | | | - John Flynn
- University of Connecticut Health Center, Farmington, Connecticut, USA
| | - John Kveton
- Yale University School of Medicine, New Haven, Connecticut, USA
| | - Marc Eisen
- Hartford Hospital, Hartford, Connecticut, USA
| | - Gerald Leonard
- University of Connecticut Health Center, Farmington, Connecticut, USA
| | | | - Craig Rodner
- University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Kourosh Parham
- University of Connecticut Health Center, Farmington, Connecticut, USA
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Kamat M, Puranik R, Vanaki S, Kamat S. An insight into the regulatory mechanisms of cells involved in resorption of dental hard tissues. J Oral Maxillofac Pathol 2014; 17:228-33. [PMID: 24250084 PMCID: PMC3830232 DOI: 10.4103/0973-029x.119736] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Dental resorptions constitute a challenge to dentistry due to the complexity of cellular and molecular biology. The various cells involved in resorption, collectively orchestrate the interplay between various cytokines, hormones, enzymes, and hard tissues influencing the progression of resorption. The concern and curiosity on this subject are not new. This paper attempts to review the various regulatory mechanisms of cells involved in resorption of mineralized dental tissues.
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Affiliation(s)
- Mamata Kamat
- Department of Oral and Maxillofacial Pathology, Modern Dental College and Hospital, Gandhinagar, Indore, India
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Abstract
The tooth works as a functional unit with its surrounding bony socket, the alveolar bone. The growth of the tooth and alveolar bone is co-ordinated so that a studied distance always separates the 2, known as the tooth-bone interface (TBI). Lack of mineralization, a crucial feature of the TBI, creates the space for the developing tooth to grow and the soft tissues of the periodontium to develop. We have investigated the interactions between the tooth and its surrounding bone during development, focusing on the impact of the developing alveolar bone on the development of the mouse first molar (M1). During development, TRAP-positive osteoclasts are found to line the TBI as bone starts to be deposited around the tooth, removing the bone as the tooth expands. An enhancement of osteoclastogenesis through RANK-RANKL signaling results in an expansion of the TBI, showing that osteoclasts are essential for defining the size of this region. Isolation of the M1 from the surrounding mesenchyme and alveolar bone leads to an expansion of the tooth germ, driven by increased proliferation, indicating that, during normal development, the growth of the tooth germ is constrained by the surrounding tissues.
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Affiliation(s)
- S A Alfaqeeh
- Department of Craniofacial Development and Stem Cell Biology, Department of Orthodontics, King's College London, London, UK, SE1 9RT
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