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Dong J, Ruan W, Duan X. Molecular-based phenotype variations in amelogenesis imperfecta. Oral Dis 2023; 29:2334-2365. [PMID: 37154292 DOI: 10.1111/odi.14599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 04/03/2023] [Accepted: 04/15/2023] [Indexed: 05/10/2023]
Abstract
Amelogenesis imperfecta (AI) is one of the typical dental genetic diseases in human. It can occur isolatedly or as part of a syndrome. Previous reports have mainly clarified the types and mechanisms of nonsyndromic AI. This review aimed to compare the phenotypic differences among the hereditary enamel defects with or without syndromes and their underlying pathogenic genes. We searched the articles in PubMed with different strategies or keywords including but not limited to amelogenesis imperfecta, enamel defects, hypoplastic/hypomaturation/hypocalcified, syndrome, or specific syndrome name. The articles with detailed clinical information about the enamel and other phenotypes and clear genetic background were used for the analysis. We totally summarized and compared enamel phenotypes of 18 nonsyndromic AI with 17 causative genes and 19 syndromic AI with 26 causative genes. According to the clinical features, radiographic or ultrastructural changes in enamel, the enamel defects were basically divided into hypoplastic and hypomineralized (hypomaturated and hypocalcified) and presented a higher heterogeneity which were closely related to the involved pathogenic genes, types of mutation, hereditary pattern, X chromosome inactivation, incomplete penetrance, and other mechanisms.The gene-specific enamel phenotypes could be an important indicator for diagnosing nonsyndromic and syndromic AI.
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Affiliation(s)
- Jing Dong
- State Key Laboratory of Military Stomatology, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, National Clinical Research Center for Oral Disease, The Fourth Military Medical University, Xi'an, China
- College of Life Sciences, Northwest University, Xi'an, China
| | - Wenyan Ruan
- State Key Laboratory of Military Stomatology, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, National Clinical Research Center for Oral Disease, The Fourth Military Medical University, Xi'an, China
| | - Xiaohong Duan
- State Key Laboratory of Military Stomatology, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, National Clinical Research Center for Oral Disease, The Fourth Military Medical University, Xi'an, China
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Bloch-Zupan A, Rey T, Jimenez-Armijo A, Kawczynski M, Kharouf N, Dure-Molla MDL, Noirrit E, Hernandez M, Joseph-Beaudin C, Lopez S, Tardieu C, Thivichon-Prince B, Dostalova T, Macek M, Alloussi ME, Qebibo L, Morkmued S, Pungchanchaikul P, Orellana BU, Manière MC, Gérard B, Bugueno IM, Laugel-Haushalter V. Amelogenesis imperfecta: Next-generation sequencing sheds light on Witkop's classification. Front Physiol 2023; 14:1130175. [PMID: 37228816 PMCID: PMC10205041 DOI: 10.3389/fphys.2023.1130175] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/06/2023] [Indexed: 05/27/2023] Open
Abstract
Amelogenesis imperfecta (AI) is a heterogeneous group of genetic rare diseases disrupting enamel development (Smith et al., Front Physiol, 2017a, 8, 333). The clinical enamel phenotypes can be described as hypoplastic, hypomineralized or hypomature and serve as a basis, together with the mode of inheritance, to Witkop's classification (Witkop, J Oral Pathol, 1988, 17, 547-553). AI can be described in isolation or associated with others symptoms in syndromes. Its occurrence was estimated to range from 1/700 to 1/14,000. More than 70 genes have currently been identified as causative. Objectives: We analyzed using next-generation sequencing (NGS) a heterogeneous cohort of AI patients in order to determine the molecular etiology of AI and to improve diagnosis and disease management. Methods: Individuals presenting with so called "isolated" or syndromic AI were enrolled and examined at the Reference Centre for Rare Oral and Dental Diseases (O-Rares) using D4/phenodent protocol (www.phenodent.org). Families gave written informed consents for both phenotyping and molecular analysis and diagnosis using a dedicated NGS panel named GenoDENT. This panel explores currently simultaneously 567 genes. The study is registered under NCT01746121 and NCT02397824 (https://clinicaltrials.gov/). Results: GenoDENT obtained a 60% diagnostic rate. We reported genetics results for 221 persons divided between 115 AI index cases and their 106 associated relatives from a total of 111 families. From this index cohort, 73% were diagnosed with non-syndromic amelogenesis imperfecta and 27% with syndromic amelogenesis imperfecta. Each individual was classified according to the AI phenotype. Type I hypoplastic AI represented 61 individuals (53%), Type II hypomature AI affected 31 individuals (27%), Type III hypomineralized AI was diagnosed in 18 individuals (16%) and Type IV hypoplastic-hypomature AI with taurodontism concerned 5 individuals (4%). We validated the genetic diagnosis, with class 4 (likely pathogenic) or class 5 (pathogenic) variants, for 81% of the cohort, and identified candidate variants (variant of uncertain significance or VUS) for 19% of index cases. Among the 151 sequenced variants, 47 are newly reported and classified as class 4 or 5. The most frequently discovered genotypes were associated with MMP20 and FAM83H for isolated AI. FAM20A and LTBP3 genes were the most frequent genes identified for syndromic AI. Patients negative to the panel were resolved with exome sequencing elucidating for example the gene involved ie ACP4 or digenic inheritance. Conclusion: NGS GenoDENT panel is a validated and cost-efficient technique offering new perspectives to understand underlying molecular mechanisms of AI. Discovering variants in genes involved in syndromic AI (CNNM4, WDR72, FAM20A … ) transformed patient overall care. Unravelling the genetic basis of AI sheds light on Witkop's AI classification.
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Affiliation(s)
- Agnes Bloch-Zupan
- Université de Strasbourg, Faculté de Chirurgie Dentaire, Strasbourg, France
- Université de Strasbourg, Institut d’études avancées (USIAS), Strasbourg, France
- Hôpitaux Universitaires de Strasbourg (HUS), Pôle de Médecine et Chirurgie Bucco-dentaires, Hôpital Civil, Centre de référence des maladies rares orales et dentaires, O-Rares, Filiére Santé Maladies rares TETE COU, European Reference Network ERN CRANIO, Strasbourg, France
- Université de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), IN-SERM U1258, CNRS- UMR7104, Illkirch, France
- Eastman Dental Institute, University College London, London, United Kingdom
| | - Tristan Rey
- Université de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), IN-SERM U1258, CNRS- UMR7104, Illkirch, France
- Hôpitaux Universitaires de Strasbourg, Laboratoires de diagnostic génétique, Institut de Génétique Médicale d’Alsace, Strasbourg, France
| | - Alexandra Jimenez-Armijo
- Université de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), IN-SERM U1258, CNRS- UMR7104, Illkirch, France
| | - Marzena Kawczynski
- Hôpitaux Universitaires de Strasbourg (HUS), Pôle de Médecine et Chirurgie Bucco-dentaires, Hôpital Civil, Centre de référence des maladies rares orales et dentaires, O-Rares, Filiére Santé Maladies rares TETE COU, European Reference Network ERN CRANIO, Strasbourg, France
| | - Naji Kharouf
- Université de Strasbourg, Laboratoire de Biomatériaux et Bioingénierie, Inserm UMR_S 1121, Strasbourg, France
| | | | - Muriel de La Dure-Molla
- Rothschild Hospital, Public Assistance-Paris Hospitals (AP-HP), Reference Center for Rare Oral and Den-tal Diseases (O-Rares), Paris, France
| | - Emmanuelle Noirrit
- Centre Hospitalier Universitaire (CHU) Rangueil, Toulouse, Competence Center for Rare Oral and Den-tal Diseases, Toulouse, France
| | - Magali Hernandez
- Centre Hospitalier Régional Universitaire de Nancy, Université de Lorraine, Competence Center for Rare Oral and Dental Diseases, Nancy, France
| | - Clara Joseph-Beaudin
- Centre Hospitalier Universitaire de Nice, Competence Center for Rare Oral and Dental Diseases, Nice, France
| | - Serena Lopez
- Centre Hospitalier Universitaire de Nantes, Competence Center for Rare Oral and Dental Diseases, Nantes, France
| | - Corinne Tardieu
- APHM, Hôpitaux Universitaires de Marseille, Hôpital Timone, Competence Center for Rare Oral and Dental Diseases, Marseille, France
| | - Béatrice Thivichon-Prince
- Centre Hospitalier Universitaire de Lyon, Competence Center for Rare Oral and Dental Diseases, Lyon, France
| | | | - Tatjana Dostalova
- Department of Stomatology (TD) and Department of Biology and Medical Genetics (MM) Charles University 2nd Faculty of Medicine and Motol University Hospital, Prague, Czechia
| | - Milan Macek
- Department of Stomatology (TD) and Department of Biology and Medical Genetics (MM) Charles University 2nd Faculty of Medicine and Motol University Hospital, Prague, Czechia
| | | | - Mustapha El Alloussi
- Faculty of Dentistry, International University of Rabat, CReSS Centre de recherche en Sciences de la Santé, Rabat, Morocco
| | - Leila Qebibo
- Unité de génétique médicale et d’oncogénétique, CHU Hassan II, Fes, Morocco
| | | | | | - Blanca Urzúa Orellana
- Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago, Chile
| | - Marie-Cécile Manière
- Université de Strasbourg, Faculté de Chirurgie Dentaire, Strasbourg, France
- Hôpitaux Universitaires de Strasbourg (HUS), Pôle de Médecine et Chirurgie Bucco-dentaires, Hôpital Civil, Centre de référence des maladies rares orales et dentaires, O-Rares, Filiére Santé Maladies rares TETE COU, European Reference Network ERN CRANIO, Strasbourg, France
| | - Bénédicte Gérard
- Hôpitaux Universitaires de Strasbourg, Laboratoires de diagnostic génétique, Institut de Génétique Médicale d’Alsace, Strasbourg, France
| | - Isaac Maximiliano Bugueno
- Université de Strasbourg, Faculté de Chirurgie Dentaire, Strasbourg, France
- Hôpitaux Universitaires de Strasbourg (HUS), Pôle de Médecine et Chirurgie Bucco-dentaires, Hôpital Civil, Centre de référence des maladies rares orales et dentaires, O-Rares, Filiére Santé Maladies rares TETE COU, European Reference Network ERN CRANIO, Strasbourg, France
- Université de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), IN-SERM U1258, CNRS- UMR7104, Illkirch, France
| | - Virginie Laugel-Haushalter
- Université de Strasbourg, Faculté de Chirurgie Dentaire, Strasbourg, France
- Université de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), IN-SERM U1258, CNRS- UMR7104, Illkirch, France
- Hôpitaux Universitaires de Strasbourg, Laboratoires de diagnostic génétique, Institut de Génétique Médicale d’Alsace, Strasbourg, France
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da Silva Figueira R, Mustafa Gomes Muniz FW, Costa LC, Silva de Moura M, Moura LDFADD, Mello de Oliveira B, Lima CCB, Rösing CK, de Lima MDDM. Association between genetic factors and molar-incisor hypomineralisation or hypomineralised second primary molar: A systematic review. Arch Oral Biol 2023; 152:105716. [PMID: 37210809 DOI: 10.1016/j.archoralbio.2023.105716] [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: 03/01/2023] [Revised: 05/01/2023] [Accepted: 05/05/2023] [Indexed: 05/23/2023]
Abstract
OBJECTIVE To determine the association between genetic factors and molar-incisor hypomineralisation (MIH) and/or hypomineralised second primary molars by means of a systematic review. DESIGN A search was performed in Medline-PubMed, Scopus, Embase and Web of Science databases; manual search and search in gray literature were also performed. Selection of articles was performed independently by two researchers. A third examiner was involved in cases of disagreement. Data extraction was performed using an Excel® spreadsheet and independent analysis was performed for each outcome. RESULTS Sixteen studies were included. There was an association between MIH and genetic variants related to amelogenesis, immune response, xenobiotic detoxification and other genes. Moreover, interactions between amelogenesis and immune response genes, and SNPs in the aquaporin gene and vitamin D receptors were associated with MIH. Greater agreement of MIH was found in pairs of monozygotic twins than dizygotic twins. The heritability of MIH was 20 %. Hypomineralised second primary molars was associated with SNPs in the hypoxia-related HIF-1 gene and methylation in genes related to amelogenesis. CONCLUSION With very low or low certainty of evidence, an association was observed between MIH and SNPs in genes associated with amelogenesis, immune response, xenobiotic detox and ion transport. Interactions between genes related to amelogenesis and immune response as well as aquaporin genes were associated to MIH. With very low certainty of evidence, hypomineralised second primary molars was associated to a hypoxia-related gene and to methylation in genes related to amelogenesis. Moreover, higher agreement of MIH in pairs of monozygotic twins than dizygotic twins was observed.
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Affiliation(s)
| | | | - Lara Carvalho Costa
- Department of Pathology and Dental Clinic, Federal University of Piauí, Teresina, Piauí, Brazil
| | - Marcoeli Silva de Moura
- Department of Pathology and Dental Clinic, Federal University of Piauí, Teresina, Piauí, Brazil
| | | | - Bibiana Mello de Oliveira
- Post Graduate Program in Genetics and Molecular Biology, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
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4
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Randall JG, Gatesy J, Springer MS. Molecular Evolutionary Analyses of Tooth Genes Support Sequential Loss of Enamel and Teeth in Baleen Whales (Mysticeti). Mol Phylogenet Evol 2022; 171:107463. [DOI: 10.1016/j.ympev.2022.107463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/16/2021] [Accepted: 03/01/2022] [Indexed: 10/18/2022]
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5
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Developmental Defects of the Teeth and Their Hard Tissues. Pediatr Dent 2022. [DOI: 10.1007/978-3-030-78003-6_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Wang SK, Zhang H, Chavez MB, Hu Y, Seymen F, Koruyucu M, Kasimoglu Y, Colvin CD, Kolli TN, Tan MH, Wang YL, Lu PY, Kim JW, Foster BL, Bartlett JD, Simmer JP, Hu JCC. Dental malformations associated with biallelic MMP20 mutations. Mol Genet Genomic Med 2020; 8:e1307. [PMID: 32495503 PMCID: PMC7434610 DOI: 10.1002/mgg3.1307] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 12/30/2022] Open
Abstract
Background Matrix metallopeptidase 20 (MMP20) is an evolutionarily conserved protease that is essential for processing enamel matrix proteins during dental enamel formation. MMP20 mutations cause human autosomal recessive pigmented hypomaturation‐type amelogenesis imperfecta (AI2A2; OMIM #612529). MMP20 is expressed in both odontoblasts and ameloblasts, but its function during dentinogenesis is unclear. Methods We characterized 10 AI kindreds with MMP20 defects, characterized human third molars and/or Mmp20−/− mice by histology, Backscattered Scanning Electron Microscopy (bSEM), µCT, and nanohardness testing. Results We identified six novel MMP20 disease‐causing mutations. Four pathogenic variants were associated with exons encoding the MMP20 hemopexin‐like (PEX) domain, suggesting a necessary regulatory function. Mutant human enamel hardness was softest (13% of normal) midway between the dentinoenamel junction (DEJ) and the enamel surface. bSEM and µCT analyses of the third molars revealed reduced mineral density in both enamel and dentin. Dentin close to the DEJ showed an average hardness number 62%–69% of control. Characterization of Mmp20−/− mouse dentin revealed a significant reduction in dentin thickness and mineral density and a transient increase in predentin thickness, indicating disturbances in dentin matrix secretion and mineralization. Conclusion These results expand the spectrum of MMP20 disease‐causing mutations and provide the first evidence for MMP20 function during dentin formation.
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Affiliation(s)
- Shih-Kai Wang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA.,Department of Pediatric Dentistry, National Taiwan University School of Dentistry, Taipei City, Taiwan R.O.C
| | - Hong Zhang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Michael B Chavez
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Yuanyuan Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Figen Seymen
- Department of Pedodontics, Istanbul University Faculty of Dentistry, Istanbul, Turkey
| | - Mine Koruyucu
- Department of Pedodontics, Istanbul University Faculty of Dentistry, Istanbul, Turkey
| | - Yelda Kasimoglu
- Department of Pedodontics, Istanbul University Faculty of Dentistry, Istanbul, Turkey
| | - Connor D Colvin
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Tamara N Kolli
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Michelle H Tan
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Yin-Lin Wang
- Department of Pediatric Dentistry, National Taiwan University School of Dentistry, Taipei City, Taiwan R.O.C
| | - Pei-Ying Lu
- Department of Pediatric Dentistry, National Taiwan University School of Dentistry, Taipei City, Taiwan R.O.C
| | - Jung-Wook Kim
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea.,Department of Molecular Genetics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Brian L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - John D Bartlett
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - James P Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Jan C-C Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
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Tremillo-Maldonado O, Molina-Frechero N, González-González R, Damián-Matsumura P, Sánchez-Pérez L, Sicco E, Suarez M, Bologna-Molina R. DNA sequencing reveals AMELX, ODAM and MMP20 variations in dental fluorosis. Arch Oral Biol 2020; 110:104626. [PMID: 31838295 DOI: 10.1016/j.archoralbio.2019.104626] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/30/2019] [Accepted: 11/26/2019] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Dental fluorosis (DF) is a dental development disorder caused by chronic fluoride overconsumption. There are differences in the susceptibility to and severity of DF in studied populations. The objective of the present study was to determine if single-nucleotide variations (SNVs) in the genes Amelogenin (AMELX), Odontogenic Ameloblast Associated (ODAM) and Matrix Metalloproteinase 20 (MMP20) are associated with DF by evaluating the relationship between variations in these genes and the degree of DF severity. SUBJECTS AND METHODS Schoolchildren from two regions of Durango State and Mexico City, Mexico, were studied. The DF phenotype was determined using the Thylstrup and Fejerskov (TF) index. DNA was obtained from the buccal mucosa of each participant, and the presence of the variations rs946252 in AMELX, rs1514392 in ODAM and rs1784418 in MMP20 was determined by bidirectional DNA sequencing. RESULTS A total of 180 DNA samples from 30 schoolchildren from 2 areas of Durango State were sequenced and analyzed. Differences in the severity of DF were found between the study areas (p = 0.006). SNVs in theMMP20 gene were present in 76.9 % of the participants in the high fluoride concentration and lower DF severity area. CONCLUSION AMELX and ODAM variations was not different between the two populations with respect to DF severity; however, the presence of rs1784418 differed between phenotypes with regard to susceptibility to DF. Therefore, MMP20 might be related to the various phenotypes of DF and may serve as a protective marker.
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Affiliation(s)
- Omar Tremillo-Maldonado
- Biological and Health Sciences Ph.D. Program, Metropolitan Autonomous University, Mexico City, Mexico
| | - Nelly Molina-Frechero
- Health and Care Department, Metropolitan Autonomous University - Xochimilco, Mexico City, Mexico.
| | | | - Pablo Damián-Matsumura
- Department of Biology of Reproduction, Metropolitan Autonomous University - Iztapalapa, Mexico City, Mexico
| | - Leonor Sánchez-Pérez
- Health and Care Department, Metropolitan Autonomous University - Xochimilco, Mexico City, Mexico
| | - Estefanía Sicco
- Molecular Pathology, Faculty of Dentistry, Universidad de la República (UDELAR), Montevideo, Uruguay
| | - Mariana Suarez
- Molecular Pathology, Faculty of Dentistry, Universidad de la República (UDELAR), Montevideo, Uruguay
| | - Ronell Bologna-Molina
- Molecular Pathology, Faculty of Dentistry, Universidad de la República (UDELAR), Montevideo, Uruguay
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Shin M, Chavez MB, Ikeda A, Foster BL, Bartlett JD. MMP20 Overexpression Disrupts Molar Ameloblast Polarity and Migration. J Dent Res 2018; 97:820-827. [PMID: 29481294 DOI: 10.1177/0022034518758657] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ameloblasts responsible for enamel formation express matrix metalloproteinase 20 (MMP20), an enzyme that cleaves enamel matrix proteins, including amelogenin (AMELX) and ameloblastin (AMBN). Previously, we showed that continuously erupting incisors from transgenic mice overexpressing active MMP20 had a massive cell infiltrate present within their enamel space, leading to enamel mineralization defects. However, effects of MMP20 overexpression on mouse molars were not analyzed, although these teeth more accurately represent human odontogenesis. Therefore, MMP20-overexpressing mice ( Mmp20+/+Tg+) were assessed by multiscale analyses, combining several approaches from high-resolution micro-computed tomography to enamel organ immunoblots. During the secretory stage at postnatal day 6 (P6), Mmp20+/+Tg+ mice had a discontinuous ameloblast layer and, unlike incisors, molar P12 maturation stage ameloblasts abnormally migrated away from the enamel layer into the stratum intermedium/stellate reticulum. TOPflash assays performed in vitro demonstrated that MMP20 expression promoted β-catenin nuclear localization and that MMP20 expression promoted invasion through Matrigel-coated filters. However, for both assays, significant differences were eliminated in the presence of the β-catenin inhibitor ICG-001. This suggests that MMP20 activity promotes cell migration via the Wnt pathway. In vivo, the unique molar migration of amelogenin-expressing ameloblasts was associated with abnormal deposition of ectopic calcified nodules surrounding the adherent enamel layer. Enamel content was assessed just prior to eruption at P15. Compared to wild-type, Mmp20+/+Tg+ molars exhibited significant reductions in enamel thickness (70%), volume (60%), and mineral density (40%), and MMP20 overexpression resulted in premature cleavage of AMBN, which likely contributed to the severe defects in enamel mineralization. In addition, Mmp20+/+Tg+ mouse molar enamel organs had increased levels of inactive p-cofilin, a protein that regulates cell polarity. These data demonstrate that increased MMP20 activity in molars causes premature degradation of ameloblastin and inactivation of cofilin, which may contribute to pathological Wnt-mediated cell migration away from the enamel layer.
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Affiliation(s)
- M Shin
- 1 Fukuoka Dental College, Sawara-ku, Fukuoka, Japan
| | - M B Chavez
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - A Ikeda
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - B L Foster
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - J D Bartlett
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
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Smith CEL, Poulter JA, Antanaviciute A, Kirkham J, Brookes SJ, Inglehearn CF, Mighell AJ. Amelogenesis Imperfecta; Genes, Proteins, and Pathways. Front Physiol 2017; 8:435. [PMID: 28694781 PMCID: PMC5483479 DOI: 10.3389/fphys.2017.00435] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 06/08/2017] [Indexed: 01/11/2023] Open
Abstract
Amelogenesis imperfecta (AI) is the name given to a heterogeneous group of conditions characterized by inherited developmental enamel defects. AI enamel is abnormally thin, soft, fragile, pitted and/or badly discolored, with poor function and aesthetics, causing patients problems such as early tooth loss, severe embarrassment, eating difficulties, and pain. It was first described separately from diseases of dentine nearly 80 years ago, but the underlying genetic and mechanistic basis of the condition is only now coming to light. Mutations in the gene AMELX, encoding an extracellular matrix protein secreted by ameloblasts during enamel formation, were first identified as a cause of AI in 1991. Since then, mutations in at least eighteen genes have been shown to cause AI presenting in isolation of other health problems, with many more implicated in syndromic AI. Some of the encoded proteins have well documented roles in amelogenesis, acting as enamel matrix proteins or the proteases that degrade them, cell adhesion molecules or regulators of calcium homeostasis. However, for others, function is less clear and further research is needed to understand the pathways and processes essential for the development of healthy enamel. Here, we review the genes and mutations underlying AI presenting in isolation of other health problems, the proteins they encode and knowledge of their roles in amelogenesis, combining evidence from human phenotypes, inheritance patterns, mouse models, and in vitro studies. An LOVD resource (http://dna2.leeds.ac.uk/LOVD/) containing all published gene mutations for AI presenting in isolation of other health problems is described. We use this resource to identify trends in the genes and mutations reported to cause AI in the 270 families for which molecular diagnoses have been reported by 23rd May 2017. Finally we discuss the potential value of the translation of AI genetics to clinical care with improved patient pathways and speculate on the possibility of novel treatments and prevention strategies for AI.
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Affiliation(s)
- Claire E L Smith
- Division of Oral Biology, School of Dentistry, St. James's University Hospital, University of LeedsLeeds, United Kingdom.,Section of Ophthalmology and Neuroscience, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - James A Poulter
- Section of Ophthalmology and Neuroscience, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Agne Antanaviciute
- Section of Genetics, School of Medicine, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Jennifer Kirkham
- Division of Oral Biology, School of Dentistry, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Steven J Brookes
- Division of Oral Biology, School of Dentistry, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Chris F Inglehearn
- Section of Ophthalmology and Neuroscience, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Alan J Mighell
- Section of Ophthalmology and Neuroscience, St. James's University Hospital, University of LeedsLeeds, United Kingdom.,Oral Medicine, School of Dentistry, University of LeedsLeeds, United Kingdom
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Gasse B, Prasad M, Delgado S, Huckert M, Kawczynski M, Garret-Bernardin A, Lopez-Cazaux S, Bailleul-Forestier I, Manière MC, Stoetzel C, Bloch-Zupan A, Sire JY. Evolutionary Analysis Predicts Sensitive Positions of MMP20 and Validates Newly- and Previously-Identified MMP20 Mutations Causing Amelogenesis Imperfecta. Front Physiol 2017; 8:398. [PMID: 28659819 PMCID: PMC5469888 DOI: 10.3389/fphys.2017.00398] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/26/2017] [Indexed: 12/21/2022] Open
Abstract
Amelogenesis imperfecta (AI) designates a group of genetic diseases characterized by a large range of enamel disorders causing important social and health problems. These defects can result from mutations in enamel matrix proteins or protease encoding genes. A range of mutations in the enamel cleavage enzyme matrix metalloproteinase-20 gene (MMP20) produce enamel defects of varying severity. To address how various alterations produce a range of AI phenotypes, we performed a targeted analysis to find MMP20 mutations in French patients diagnosed with non-syndromic AI. Genomic DNA was isolated from saliva and MMP20 exons and exon-intron boundaries sequenced. We identified several homozygous or heterozygous mutations, putatively involved in the AI phenotypes. To validate missense mutations and predict sensitive positions in the MMP20 sequence, we evolutionarily compared 75 sequences extracted from the public databases using the Datamonkey webserver. These sequences were representative of mammalian lineages, covering more than 150 million years of evolution. This analysis allowed us to find 324 sensitive positions (out of the 483 MMP20 residues), pinpoint functionally important domains, and build an evolutionary chart of important conserved MMP20 regions. This is an efficient tool to identify new- and previously-identified mutations. We thus identified six functional MMP20 mutations in unrelated families, finding two novel mutated sites. The genotypes and phenotypes of these six mutations are described and compared. To date, 13 MMP20 mutations causing AI have been reported, making these genotypes and associated hypomature enamel phenotypes the most frequent in AI.
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Affiliation(s)
- Barbara Gasse
- Institut de Biologie Paris-Seine, UMR 7138-Evolution Paris-Seine, Sorbonne Universités, Université Pierre et Marie CurieParis, France
| | - Megana Prasad
- Laboratoire de Génétique Médicale, Institut National de la Santé et de la Recherche Médicale UMRS_1112, Institut de Génétique Médicale d'Alsace, FMTS, Université de StrasbourgStrasbourg, France
| | - Sidney Delgado
- Institut de Biologie Paris-Seine, UMR 7138-Evolution Paris-Seine, Sorbonne Universités, Université Pierre et Marie CurieParis, France
| | - Mathilde Huckert
- Laboratoire de Génétique Médicale, Institut National de la Santé et de la Recherche Médicale UMRS_1112, Institut de Génétique Médicale d'Alsace, FMTS, Université de StrasbourgStrasbourg, France.,Faculté de Chirurgie Dentaire, Université de StrasbourgStrasbourg, France
| | - Marzena Kawczynski
- Faculté de Chirurgie Dentaire, Université de StrasbourgStrasbourg, France.,Pôle de Médecine et Chirurgie Bucco-Dentaires, Centre de Référence des Manifestations Odontologiques des Maladies Rares, O-Rares, Hôpitaux Universitaires de StrasbourgStrasbourg, France
| | - Annelyse Garret-Bernardin
- Faculté de Chirurgie Dentaire, Université de StrasbourgStrasbourg, France.,Unit of Dentistry, IRCCS, Bambino Gesù Children's HospitalRome, Italy
| | - Serena Lopez-Cazaux
- Faculté de Chirurgie Dentaire, Département d'Odontologie Pédiatrique, Centre de Compétences Maladies Rares, CHU Hôtel Dieu, Service d'odontologie Conservatrice et PédiatriqueNantes, France
| | - Isabelle Bailleul-Forestier
- Faculté de Chirurgie Dentaire, CHU de Toulouse, Centre de Compétences Maladies Rares, Odontologie Pédiatrique, Université Paul SabatierToulouse, France
| | - Marie-Cécile Manière
- Faculté de Chirurgie Dentaire, Université de StrasbourgStrasbourg, France.,Pôle de Médecine et Chirurgie Bucco-Dentaires, Centre de Référence des Manifestations Odontologiques des Maladies Rares, O-Rares, Hôpitaux Universitaires de StrasbourgStrasbourg, France
| | - Corinne Stoetzel
- Laboratoire de Génétique Médicale, Institut National de la Santé et de la Recherche Médicale UMRS_1112, Institut de Génétique Médicale d'Alsace, FMTS, Université de StrasbourgStrasbourg, France
| | - Agnès Bloch-Zupan
- Faculté de Chirurgie Dentaire, Université de StrasbourgStrasbourg, France.,Pôle de Médecine et Chirurgie Bucco-Dentaires, Centre de Référence des Manifestations Odontologiques des Maladies Rares, O-Rares, Hôpitaux Universitaires de StrasbourgStrasbourg, France.,Centre Européen de Recherche en Biologie et en Médecine, Centre National de la Recherche Scientifique UMR7104, Institut National de la Santé et de la Recherche Médicale U964, Institut de Génétique et de Biologie Moléculaire and Cellulaire, Université de StrasbourgIllkirch, France.,Institut d'Etudes Avancées, Université de Strasbourg, USIASStrasbourg, France.,Eastman Dental Institute, University College LondonLondon, United Kingdom
| | - Jean-Yves Sire
- Institut de Biologie Paris-Seine, UMR 7138-Evolution Paris-Seine, Sorbonne Universités, Université Pierre et Marie CurieParis, France
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11
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Kim YJ, Kang J, Seymen F, Koruyucu M, Gencay K, Shin TJ, Hyun HK, Lee ZH, Hu JCC, Simmer JP, Kim JW. Analyses of MMP20 Missense Mutations in Two Families with Hypomaturation Amelogenesis Imperfecta. Front Physiol 2017; 8:229. [PMID: 28473773 PMCID: PMC5397402 DOI: 10.3389/fphys.2017.00229] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/31/2017] [Indexed: 11/25/2022] Open
Abstract
Amelogenesis imperfecta is a group of rare inherited disorders that affect tooth enamel formation, quantitatively and/or qualitatively. The aim of this study was to identify the genetic etiologies of two families presenting with hypomaturation amelogenesis imperfecta. DNA was isolated from peripheral blood samples obtained from participating family members. Whole exome sequencing was performed using DNA samples from the two probands. Sequencing data was aligned to the NCBI human reference genome (NCBI build 37.2, hg19) and sequence variations were annotated with the dbSNP build 138. Mutations in MMP20 were identified in both probands. A homozygous missense mutation (c.678T>A; p.His226Gln) was identified in the consanguineous Family 1. Compound heterozygous MMP20 mutations (c.540T>A, p.Tyr180* and c.389C>T, p.Thr130Ile) were identified in the non-consanguineous Family 2. Affected persons in Family 1 showed hypomaturation AI with dark brown discoloration, which is similar to the clinical phenotype in a previous report with the same mutation. However, the dentition of the Family 2 proband exhibited slight yellowish discoloration with reduced transparency. Functional analysis showed that the p.Thr130Ile mutant protein had reduced activity of MMP20, while there was no functional MMP20 in the Family 1 proband. These results expand the mutational spectrum of the MMP20 and broaden our understanding of genotype-phenotype correlations in amelogenesis imperfecta.
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Affiliation(s)
- Youn Jung Kim
- Department of Molecular Genetics and Dental Research Institute, School of Dentistry, Seoul National UniversitySeoul, Korea
| | - Jenny Kang
- Department of Pediatric Dentistry and Dental Research Institute, School of Dentistry, Seoul National UniversitySeoul, Korea
| | - Figen Seymen
- Faculty of Dentistry, Department of Pedodontics, Istanbul UniversityIstanbul, Turkey
| | - Mine Koruyucu
- Faculty of Dentistry, Department of Pedodontics, Istanbul UniversityIstanbul, Turkey
| | - Koray Gencay
- Faculty of Dentistry, Department of Pedodontics, Istanbul UniversityIstanbul, Turkey
| | - Teo Jeon Shin
- Department of Pediatric Dentistry and Dental Research Institute, School of Dentistry, Seoul National UniversitySeoul, Korea
| | - Hong-Keun Hyun
- Department of Pediatric Dentistry and Dental Research Institute, School of Dentistry, Seoul National UniversitySeoul, Korea
| | - Zang Hee Lee
- Department of Cell and Developmental Biology and Dental Research Institute, School of Dentistry, Seoul National UniversitySeoul, Korea
| | - Jan C-C Hu
- Department of Biologic and Materials Sciences, University of Michigan School of DentistryAnn Arbor, MI, USA
| | - James P Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of DentistryAnn Arbor, MI, USA
| | - Jung-Wook Kim
- Department of Molecular Genetics and Dental Research Institute, School of Dentistry, Seoul National UniversitySeoul, Korea.,Department of Pediatric Dentistry and Dental Research Institute, School of Dentistry, Seoul National UniversitySeoul, Korea
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12
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Antunes LA, Antunes LS, Küchler EC, Lopes LB, Moura A, Bigonha RS, Abreu FV, Granjeiro JM, de Amorim LMDF, Paixão ICNP. Analysis of the association between polymorphisms in MMP2, MMP3, MMP9, MMP20, TIMP1, and TIMP2 genes with white spot lesions and early childhood caries. Int J Paediatr Dent 2016; 26:310-9. [PMID: 26371789 DOI: 10.1111/ipd.12202] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Matrix metalloproteinases and their inhibitors might be involved in enamel formation. AIM This study aimed to evaluate the association between polymorphisms in MMP2, MMP3, MMP9, MMP20, TIMP1, and TIMP2 with white spot lesions (WSL) and early childhood caries (ECC). DESIGN A cross-sectional study was performed on 786 children aged from 2 to 6 years in Brazil. After clinical evaluation, they were classified into groups with disease (the presence of WSL and/or ECC) and without disease (the absence of WSL or ECC). Genotyping of the selected polymorphisms was carried out with TaqMan real-time PCR, using genomic DNA extracted from buccal cells. Allele and genotype frequencies were compared between groups. Chi-square test, odds ratio (OR), and logistic regression were used (P ≤ 0.05). RESULTS The dmft score was 1.3 (SD: 2.4), and 41.34% of the children have at least one caries lesion. In MMP9, the GG genotype was more frequent in the group without disease (P = 0.006). In a recessive model, WSL was associated with the marker rs1711437 in MMP20 (P = 0.019; OR = 1.20, 95% CI 1.02-1.42). The marker rs1784418 in MMP20 showed an association between the allele G distribution for the WSL group (P = 0.020; OR = 0.73, 95% CI 0.55-0.96). CONCLUSION MMP9 and MMP20 are involved in WSL and ECC development.
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Affiliation(s)
- Lívia Azeredo Antunes
- School of Dentistry, Fluminense Federal University, Nova Friburgo, Brazil.,Biology Institute, Fluminense Federal University, Niterói, Brazil.,Clinical Research Unit, Fluminense Federal University, Niterói, Brazil
| | - Leonardo Santos Antunes
- School of Dentistry, Fluminense Federal University, Nova Friburgo, Brazil.,Clinical Research Unit, Fluminense Federal University, Niterói, Brazil
| | | | | | - Alex Moura
- Clinical Research Unit, Fluminense Federal University, Niterói, Brazil
| | | | | | - José Mauro Granjeiro
- Directory of Programs, National Institute of Metrology, Quality and Technology (INMETRO), Duque de Caxias, Brazil
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13
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Hu Y, Smith CE, Richardson AS, Bartlett JD, Hu JCC, Simmer JP. MMP20, KLK4, and MMP20/KLK4 double null mice define roles for matrix proteases during dental enamel formation. Mol Genet Genomic Med 2015; 4:178-96. [PMID: 27066511 PMCID: PMC4799876 DOI: 10.1002/mgg3.194] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/12/2015] [Accepted: 11/13/2015] [Indexed: 01/08/2023] Open
Abstract
Matrix metalloproteinase 20 (MMP20) and kallikrein‐related peptidase 4 (KLK4) are secreted proteinases that are essential for proper dental enamel formation. We characterized and compared enamel formed in wild‐type, Mmp20−/−, Klk4−/−, Mmp20+/−Klk4+/−, and Mmp20−/−Klk4−/− mice using dissecting and light microscopy, backscattered scanning electron microscopy (bSEM), SEM, microcomputed tomography (μCT), and energy‐dispersive X‐ray analysis (EDX). Following eruption, fractures were observed on Mmp20−/−, Klk4−/−, Mmp20+/−Klk4+/−, and Mmp20−/−Klk4−/− molars. Failure of the enamel in the Mmp20+/−Klk4+/− molars was unexpected and suggested that digenic effects could contribute to the etiology of amelogenesis imperfecta in humans. Micro‐CT analyses of hemimandibles demonstrated significantly reduced high‐density enamel volume in the Mmp20−/− and Klk4−/− mice relative to the wild‐type, which was further reduced in Mmp20−/−Klk4−/− mice. bSEM images of 7‐week Mmp20−/− and Mmp20−/−Klk4−/− mandibular incisors showed rough, pitted enamel surfaces with numerous indentations and protruding nodules. The Mmp20+/− and Mmp20+/−Klk4+/− incisors showed prominent, evenly spaced, horizontal ridges that were more distinct in Mmp20+/−Klk4+/− incisors relative to Mmp20+/− incisors due to the darkening of the valleys between the ridges. In cross sections, the Mmp20−/− and Mmp20−/−Klk4−/− exhibited three distinct layers. The outer layer exhibited a disturbed elemental composition and an irregular enamel surface covered with nodules. The Mmp20 null enamel was apparently unable to withstand the sheer forces associated with eruption and separated from dentin during development. Cells invaded the cracks and interposed between the dentin and enamel layers. MMP20 and KLK4 serve overlapping and complementary functions to harden enamel by removing protein, but MMP20 potentially serves multiple additional functions necessary for the adherence of enamel to dentin, the release of intercellular protein stores into the enamel matrix, the retreat of ameloblasts to facilitate thickening of the enamel layer, and the timely transition of ameloblasts to maturation.
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Affiliation(s)
- Yuanyuan Hu
- Departments of Biologic and Materials Sciences University of Michigan School of Dentistry 1210 Eisenhower Place Ann Arbor Michigan 48108
| | - Charles E Smith
- Departments of Biologic and Materials SciencesUniversity of Michigan School of Dentistry1210 Eisenhower PlaceAnn ArborMichigan48108; Facility for Electron Microscopy ResearchDepartment of Anatomy and Cell Biology and Faculty of DentistryMcGill UniversityMontrealQuebecH3A 2B2Canada
| | - Amelia S Richardson
- Departments of Biologic and Materials Sciences University of Michigan School of Dentistry 1210 Eisenhower Place Ann Arbor Michigan 48108
| | - John D Bartlett
- Office of Research College of Dentistry Ohio State University 4139 Postle Hall, 305 W. 12th Ave. Columbus Ohio 43210
| | - Jan C C Hu
- Departments of Biologic and Materials Sciences University of Michigan School of Dentistry 1210 Eisenhower Place Ann Arbor Michigan 48108
| | - James P Simmer
- Departments of Biologic and Materials Sciences University of Michigan School of Dentistry 1210 Eisenhower Place Ann Arbor Michigan 48108
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14
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Seymen F, Park JC, Lee KE, Lee HK, Lee DS, Koruyucu M, Gencay K, Bayram M, Tuna EB, Lee ZH, Kim YJ, Kim JW. Novel MMP20 and KLK4 Mutations in Amelogenesis Imperfecta. J Dent Res 2015; 94:1063-9. [PMID: 26124219 DOI: 10.1177/0022034515590569] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In order to achieve highly mineralized tooth enamel, enamel proteinases serve the important function of removing the remaining organic matrix in the mineralization and maturation of the enamel matrix. Mutations in the kallikrein 4 (KLK4), enamelysin (MMP20), and WDR72 genes have been identified as causing hypomaturation enamel defects in an autosomal-recessive hereditary pattern. In this report, 2 consanguineous families with a hypomaturation-type enamel defect were recruited, and mutational analysis was performed to determine the molecular genetic etiology of the disease. Whole exome sequencing and autozygosity mapping identified novel homozygous mutations in the KLK4 (c.620_621delCT, p.Ser207Trpfs*38) and MMP20 (c.1054G>A, p.Glu352Lys) genes. Further analysis on the effect of the mutations on the translation, secretion, and function of KLK4 and MMP20 revealed that mutant KLK4 was degraded intracellularly and became inactive while mutant MMP20 was expressed at a normal level but secreted only minimally with proteolytic function.
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Affiliation(s)
- F Seymen
- Department of Pedodontics, Istanbul University, Istanbul, Turkey
| | - J-C Park
- Department of Cell and Developmental Biology & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - K-E Lee
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - H-K Lee
- Department of Cell and Developmental Biology & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - D-S Lee
- Department of Cell and Developmental Biology & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - M Koruyucu
- Department of Pedodontics, Istanbul University, Istanbul, Turkey
| | - K Gencay
- Department of Pedodontics, Istanbul University, Istanbul, Turkey
| | - M Bayram
- Department of Pedodontics, Istanbul University, Istanbul, Turkey
| | - E B Tuna
- Department of Pedodontics, Istanbul University, Istanbul, Turkey
| | - Z H Lee
- Department of Cell and Developmental Biology & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Y-J Kim
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - J-W Kim
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea Department of Molecular Genetics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
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15
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Koli K, Saxena G, Ogbureke KUE. Expression of Matrix Metalloproteinase (MMP)-20 and Potential Interaction with Dentin Sialophosphoprotein (DSPP) in Human Major Salivary Glands. J Histochem Cytochem 2015; 63:524-33. [PMID: 25805840 DOI: 10.1369/0022155415580817] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/12/2015] [Indexed: 12/23/2022] Open
Abstract
Matrix metalloproteinase-20 (MMP-20) expression is widely regarded as tooth-specific, with expression limited to dental hard tissues. Necessary for sound enamel formation, MMP-20 and MMP-2 proteolytically process dentin sialophosphoprotein (DSPP) into dentin sialoprotein, dentin phosphoprotein, and dentin glycoprotein during tooth formation. In the mid-2000s, three members of the small integrin-binding ligand N-linked glycoproteins (SIBLINGs) were reported to bind specifically with high affinity (nM) to, and activate, three MMPs in vitro: bone sialoprotein with MMP-2; osteopontin with MMP-3; and dentin matrix protein1 with MMP-9. The SIBLING-MMP interaction was confirmed in biological systems such as the ducts of salivary glands, where all five members of the SIBLINGs are expressed. Recently, we documented MMP-20 expression and interaction with DSPP (another member of the SIBLING family) in human oral squamous cell carcinoma. Here we report the expression of MMP-20, and confirm its co-expression and potential interaction with DSPP in human major salivary gland tissues and cell line using immunohistochemistry, immunofluorescence, western blot, quantitative RT-PCR, and proximity ligation assay. This report reinforces our earlier suggestion that the SIBLING-MMP complexes may be involved in the turnover of extracellular proteins damaged by oxidation byproducts in metabolically active duct epithelial systems.
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Affiliation(s)
- Komal Koli
- Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, Texas (KK, GS, KUEO)
| | - Geetu Saxena
- Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, Texas (KK, GS, KUEO)
| | - Kalu U E Ogbureke
- Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, Texas (KK, GS, KUEO)
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16
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POURHASHEMI SJ, GHANDEHARI MOTLAGH M, MEIGHANI G, EBRAHIMI TAKALOO A, MANSOURI M, MOHANDES F, MIRZAII M, KHOSHZABAN A, MOSHTAGHI F, ABEDKHOJASTEH H, HEIDARI M. Missense Mutation in Fam83H Gene in Iranian Patients with Amelogenesis Imperfecta. IRANIAN JOURNAL OF PUBLIC HEALTH 2014; 43:1680-7. [PMID: 26171361 PMCID: PMC4499090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 09/10/2014] [Indexed: 11/03/2022]
Abstract
BACKGROUND Amelogenesis Imperfecta (AI) is a disorder of tooth development where there is an abnormal formation of enamel or the external layer of teeth. The aim of this study was to screen mutations in the four most important candidate genes, ENAM, KLK4, MMP20 and FAM83H responsible for amelogenesis imperfect. METHODS Geneomic DNA was isolated from five Iranian families with 22 members affected with enamel malformations. The PCR amplifications were typically carried out for amplification the coding regions for AI patients and unaffected family members. The PCR products were subjected to direct sequencing. The pedigree analysis was performed using Cyrillic software. RESULTS One family had four affected members with autosomal dominant hypocalcified amelogenesis imperfecta (ADHPCAI); pedigree analysis revealed four consanguineous families with 18 patients with autosomal recessive hypoplastic amelogenesis imperfecta (ARHPAI). One non-synonymous single-nucleotide substitution, c.1150T>A, p. Ser 342Thr was identified in the FAM83H, which resulted in ADHCAI. Furthermore, different polymorphisms or unclassified variants were detected in MMP20, ENAM and KLK4. CONCLUSION Our results are consistent with other studies and provide further evidence for pathogenic mutations of FAM83H gene. These findings suggest different loci and genes could be implicated in the pathogenesis of AI.
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Affiliation(s)
- S Jalal POURHASHEMI
- Dept. of Pediatric Dentistry, Tehran University of Medical Sciences, Tehran, Iran,Dept. of Pediatric Dentistry, Tehran University of Medical Sciences, International Campus, Tehran, Iran
| | | | - Ghasem MEIGHANI
- Dept. of Pediatric Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Mahsa MANSOURI
- Dept. of Pediatric Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh MOHANDES
- Dept. of Pediatric Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam MIRZAII
- Dept. of Pediatric Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahad KHOSHZABAN
- Dept. Bio Dental Materials, Dental Faculty of Tehran University of Medical Sciences, Tehran, Iran,Stem Cell Preparation Unit, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Faranak MOSHTAGHI
- Stem Cell Preparation Unit, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Hoda ABEDKHOJASTEH
- Stem Cell Preparation Unit, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mansour HEIDARI
- Stem Cell Preparation Unit, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran,Dept. of Medical Genetics, Tehran University of Medical Sciences, Tehran, Iran,Corresponding Author:
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17
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Is there new hope for therapeutic matrix metalloproteinase inhibition? Nat Rev Drug Discov 2014; 13:904-27. [DOI: 10.1038/nrd4390] [Citation(s) in RCA: 524] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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18
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Abstract
Human enamel development of the permanent teeth takes place during childhood and stresses encountered during this period can have lasting effects on the appearance and structural integrity of the enamel. One of the most common examples of this is the development of dental fluorosis after childhood exposure to excess fluoride, an elemental agent used to increase enamel hardness and prevent dental caries. Currently the molecular mechanism responsible for dental fluorosis remains unknown; however, recent work suggests dental fluorosis may be the result of activated stress response pathways in ameloblasts during the development of permanent teeth. Using fluorosis as an example, the role of stress response pathways during enamel maturation is discussed.
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19
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Gao Y, Zhang L, Xiang L, Li B, Liu X, Wang Y, Sun Y. Transforming growth factor-β1 regulates expression of the matrix metalloproteinase 20 (Mmp20) gene through a mechanism involving the transcription factor, myocyte enhancer factor-2C, in ameloblast lineage cells. Eur J Oral Sci 2014; 122:114-20. [PMID: 24495128 DOI: 10.1111/eos.12115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2013] [Indexed: 12/28/2022]
Abstract
Matrix metalloproteinase-20 (Mmp20) plays an essential role in amelogenesis during tooth development and is regulated by transforming growth factor-β1 (TGF-β1) in mouse ameloblast lineage cells (ALCs). The objective of this study was to explore the role of myocyte enhancer factor-2C (MEF2C), a key transcription factor in craniofacial development, in TGF-β1-induced Mmp20 gene expression. We investigated Mmp20 expression in ALCs over-expressing MEF2C and in ALCs with MEF2C knocked down. We also analyzed activity of the Mmp20 promoter using a transient reporter gene-expression assay in cultured ALCs. Putative transcription factor-binding sites for MEF2C and TGF-β1 on the Mmp20 promoter were analyzed with bioinformatics tools and examined using an electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP). The expression of Mmp20 was induced, in a dose-dependent manner, by MEF2C over-expression, and TGF-β1-induced Mmp20 expression was blocked by MEF2C knockdown in ALCs. There was a TGF-β1/MEF2C-responsive region, including a putative MEF2-binding site, between base pairs -356 and -73 of the Mmp20 promoter. Mutation of the putative MEF2-binding site significantly reduced Mmp20 promoter activity upon activation with MEF2C or TGF-β1. In conclusion, TGF-β1-induced Mmp20 expression in ALCs was regulated through the MEF2-binding site on the Mmp20 promoter and thus mediated by the MEF2C signaling pathway.
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Affiliation(s)
- Yuguang Gao
- Department of Stomatology, Hospital affiliated to Binzhou Medical University, Binzhou City, China
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20
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Shin M, Hu Y, Tye CE, Guan X, Deagle CC, Antone JV, Smith CE, Simmer JP, Bartlett JD. Matrix metalloproteinase-20 over-expression is detrimental to enamel development: a Mus musculus model. PLoS One 2014; 9:e86774. [PMID: 24466234 PMCID: PMC3900650 DOI: 10.1371/journal.pone.0086774] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 12/17/2013] [Indexed: 12/25/2022] Open
Abstract
Background Matrix metalloproteinase-20 (Mmp20) ablated mice have enamel that is thin and soft with an abnormal rod pattern that abrades from the underlying dentin. We asked if introduction of transgenes expressing Mmp20 would revert this Mmp20 null phenotype back to normal. Unexpectedly, for transgenes expressing medium or high levels of Mmp20, we found opposite enamel phenotypes depending on the genetic background (Mmp20−/− or Mmp20+/+) in which the transgenes were expressed. Methodology/Principal Findings Amelx-promoter-Mmp20 transgenic founder mouse lines were assessed for transgene expression and those expressing low, medium or high levels of Mmp20 were selected for breeding into the Mmp20 null background. Regardless of expression level, each transgene brought the null enamel back to full thickness. However, the high and medium expressing Mmp20 transgenes in the Mmp20 null background had significantly harder more mineralized enamel than did the low transgene expresser. Strikingly, when the high and medium expressing Mmp20 transgenes were present in the wild-type background, the enamel was significantly less well mineralized than normal. Protein gel analysis of enamel matrix proteins from the high and medium expressing transgenes present in the wild-type background demonstrated that greater than normal amounts of cleavage products and smaller quantities of higher molecular weight proteins were present within their enamel matrices. Conclusions/Significance Mmp20 expression levels must be within a specific range for normal enamel development to occur. Creation of a normally thick enamel layer may occur over a wider range of Mmp20 expression levels, but acquisition of normal enamel hardness has a narrower range. Since over-expression of Mmp20 results in decreased enamel hardness, this suggests that a balance exists between cleaved and full-length enamel matrix proteins that are essential for formation of a properly hardened enamel layer. It also suggests that few feedback controls are present in the enamel matrix to prevent excessive MMP20 activity.
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Affiliation(s)
- Masashi Shin
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
| | - Yuanyuan Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan, United States of America
| | - Coralee E. Tye
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
| | - Xiaomu Guan
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
| | - Craig C. Deagle
- Program in Endodontics, Harvard School of Dental Medicine, Boston Massachusetts, United States of America
| | - Jerry V. Antone
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
| | - Charles E. Smith
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan, United States of America
- Facility for Electron Microscopy Research, Department of Anatomy & Cell Biology, and Faculty of Dentistry, McGill University, Montreal, QC, Canada
| | - James P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan, United States of America
| | - John D. Bartlett
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
- * E-mail:
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Guan X, Bartlett JD. MMP20 modulates cadherin expression in ameloblasts as enamel develops. J Dent Res 2013; 92:1123-8. [PMID: 24067343 DOI: 10.1177/0022034513506581] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Matrix metalloproteinase-20 (enamelysin, MMP20) is essential for dental enamel development. Seven different MMP20 mutations in humans cause non-syndromic enamel malformations, termed amelogenesis imperfecta, and ablation of Mmp20 in mice results in thin brittle enamel with a dysplastic rod pattern. Healthy enamel formation requires the sliding movement of ameloblasts in rows during the secretory stage of development. This is essential for formation of the characteristic decussating enamel rod pattern observed in rodents, and this is also when MMP20 is secreted into the enamel matrix. Therefore, we propose that MMP20 facilitates ameloblast movement by cleaving ameloblast cell-cell contacts. Here we show that MMP20 cleaves the extracellular domains of the E- and N-cadherin adherens junction proteins, that both E- and N-cadherin transcripts are expressed at significantly higher levels in Mmp20 null vs. wild-type (WT) mice, and that in Mmp20 ablated mice, high-level ameloblast N-cadherin expression persists during the maturation stage of development. Furthermore, we show that E-cadherin gene expression is down-regulated from the pre-secretory to the secretory stage, while N-cadherin levels are up-regulated. This E- to N-cadherin switch supports epithelial migration in other tissues and may be an important event necessary for the ameloblasts to start moving in rows that slide by one another.
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Affiliation(s)
- X Guan
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, 245 First Street, Cambridge, MA 02142, USA
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Bartlett JD. Dental enamel development: proteinases and their enamel matrix substrates. ISRN DENTISTRY 2013; 2013:684607. [PMID: 24159389 PMCID: PMC3789414 DOI: 10.1155/2013/684607] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 07/15/2013] [Indexed: 12/31/2022]
Abstract
This review focuses on recent discoveries and delves in detail about what is known about each of the proteins (amelogenin, ameloblastin, and enamelin) and proteinases (matrix metalloproteinase-20 and kallikrein-related peptidase-4) that are secreted into the enamel matrix. After an overview of enamel development, this review focuses on these enamel proteins by describing their nomenclature, tissue expression, functions, proteinase activation, and proteinase substrate specificity. These proteins and their respective null mice and human mutations are also evaluated to shed light on the mechanisms that cause nonsyndromic enamel malformations termed amelogenesis imperfecta. Pertinent controversies are addressed. For example, do any of these proteins have a critical function in addition to their role in enamel development? Does amelogenin initiate crystallite growth, does it inhibit crystallite growth in width and thickness, or does it do neither? Detailed examination of the null mouse literature provides unmistakable clues and/or answers to these questions, and this data is thoroughly analyzed. Striking conclusions from this analysis reveal that widely held paradigms of enamel formation are inadequate. The final section of this review weaves the recent data into a plausible new mechanism by which these enamel matrix proteins support and promote enamel development.
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Affiliation(s)
- John D. Bartlett
- Harvard School of Dental Medicine & Chair, Department of Mineralized Tissue Biology, The Forsyth Institute, 245 First Street, Cambridge MA 02142, USA
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23
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Sahlberg C, Pavlic A, Ess A, Lukinmaa PL, Salmela E, Alaluusua S. Combined effect of amoxicillin and sodium fluoride on the structure of developing mouse enamel in vitro. Arch Oral Biol 2013; 58:1155-64. [DOI: 10.1016/j.archoralbio.2013.03.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 12/19/2012] [Accepted: 03/12/2013] [Indexed: 10/26/2022]
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24
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Gasse B, Karayigit E, Mathieu E, Jung S, Garret A, Huckert M, Morkmued S, Schneider C, Vidal L, Hemmerlé J, Sire JY, Bloch-Zupan A. Homozygous and compound heterozygous MMP20 mutations in amelogenesis imperfecta. J Dent Res 2013; 92:598-603. [PMID: 23625376 DOI: 10.1177/0022034513488393] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In this article, we focus on hypomaturation autosomal-recessive-type amelogenesis imperfecta (type IIA2) and describe 2 new causal Matrix metalloproteinase 20 (MMP20) mutations validated in two unrelated families: a missense mutation p.T130I at the expected homozygous state, and a compound heterozygous mutation having the same mutation combined with a nucleotide deletion, leading to a premature stop codon (p.N120fz*2). We characterized the enamel structure of the latter case using scanning electron microscopy analysis and microanalysis (Energy-dispersive X-ray Spectroscopy, EDX) and confirmed the hypomaturation-type amelogenesis imperfecta as identified in the clinical diagnosis. The mineralized content was slightly decreased, with magnesium substituting for calcium in the crystal structure. The anomalies affected enamel with minimal inter-rod enamel present and apatite crystals perpendicular to the enamel prisms, suggesting a possible new role for MMP20 in enamel formation.
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Affiliation(s)
- B Gasse
- Research group Evolution & Développement du Squelette-EDS, UMR 7138-SAE, Université Pierre et Marie Curie, Paris, France
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25
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Bartlett JD, Smith CE. Modulation of cell-cell junctional complexes by matrix metalloproteinases. J Dent Res 2012; 92:10-7. [PMID: 23053846 DOI: 10.1177/0022034512463397] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The ameloblast cell layer of the enamel organ is in contact with the forming enamel as it develops into the hardest substance in the body. Ameloblasts move in groups that slide by one another as the enamel layer thickens. Each ameloblast is responsible for the formation of one enamel rod, and the rods are the mineralized trail that moving ameloblasts leave behind. Matrix metalloproteinases (MMPs) facilitate cell movement in various tissues during development, and in this review we suggest that the tooth-specific MMP, enamelysin (MMP20), facilitates ameloblast movements during enamel development. Mmp20 null mice have thin brittle enamel with disrupted rod patterns that easily abrades from the underlying dentin. Strikingly, the Mmp20 null mouse enamel organ morphology is noticeably dysplastic during late-stage development, when MMP20 is no longer expressed. We suggest that in addition to its role of cleaving enamel matrix proteins, MMP20 also cleaves junctional complexes present on ameloblasts to foster the cell movement necessary for formation of the decussating enamel rod pattern. Therefore, inactivation of MMP20 would result in tight ameloblast cell-cell attachments that may cause maturation-stage enamel organ dysplasia. The tight ameloblast attachments would also preclude the ameloblast movement necessary to form decussating enamel rod patterns.
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Affiliation(s)
- J D Bartlett
- Department of Mineralized Tissue Biology, Forsyth Institute, Harvard School of Dental Medicine, Cambridge, MA, USA.
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Simmer JP, Richardson AS, Smith CE, Hu Y, Hu JCC. Expression of kallikrein-related peptidase 4 in dental and non-dental tissues. Eur J Oral Sci 2012; 119 Suppl 1:226-33. [PMID: 22243250 DOI: 10.1111/j.1600-0722.2011.00834.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Kallikrein-related peptidase 4 (KLK4) is critical for proper dental enamel formation. Klk4 null mice, and humans with two defective KLK4 alleles have obvious enamel defects, with no other apparent phenotype. KLK4 mRNA or protein is reported to be present in tissues besides teeth, including prostate, ovary, kidney, liver, and salivary gland. In this study we used the Klk4 knockout/NLS-lacZ knockin mouse to assay Klk4 expression using β-galactosidase histochemistry. Incubations for 5 h were used to detect KLK4 expression with minimal endogenous background, while overnight incubations susceptible to false positives were used to look for trace KLK4 expression. Developing maxillary molars at postnatal days 5, 6, 7, 8, and 14, developing mandibular incisors at postnatal day 14, and selected non-dental tissues from adult wild-type and Klk4(lacZ/lacZ) mice were examined by X-gal histochemistry. After 5 h of incubation, X-gal staining was observed specifically in the nuclei of maturation-stage ameloblasts in molars and incisors from Klk4(lacZ/lacZ) mice and was detected weakly in the nuclei of salivary gland ducts and in patches of prostate epithelia. We conclude that KLK4 is predominantly a tooth-specific protease with low expression in submandibular salivary gland and prostate, and with no detectable expression in liver, kidney, testis, ovary, oviduct, epididymis, and vas deferens.
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Affiliation(s)
- James P Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48108, USA.
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Bartlett JD, Skobe Z, Nanci A, Smith CE. Matrix metalloproteinase 20 promotes a smooth enamel surface, a strong dentino-enamel junction, and a decussating enamel rod pattern. Eur J Oral Sci 2012; 119 Suppl 1:199-205. [PMID: 22243247 DOI: 10.1111/j.1600-0722.2011.00864.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mutations of the matrix metalloproteinase 20 (MMP20, enamelysin) gene cause autosomal-recessive amelogenesis imperfecta, and Mmp20 ablated mice also have malformed dental enamel. Here we showed that Mmp20 null mouse secretory-stage ameloblasts maintain a columnar shape and are present as a single layer of cells. However, the maturation-stage ameloblasts from null mouse cover extraneous nodules of ectopic calcified material formed at the enamel surface. Remarkably, nodule formation occurs in null mouse enamel when MMP20 is normally no longer expressed. The malformed enamel in Mmp20 null teeth was loosely attached to the dentin and the entire enamel layer tended to separate from the dentin, indicative of a faulty dentino-enamel junction (DEJ). The enamel rod pattern was also altered in Mmp20 null mice. Each enamel rod is formed by a single ameloblast and is a mineralized record of the migration path of the ameloblast that formed it. The enamel rods in Mmp20 null mice were grossly malformed or absent, indicating that the ameloblasts do not migrate properly when backing away from the DEJ. Thus, MMP20 is required for ameloblast cell movement necessary to form the decussating enamel rod patterns, for the prevention of ectopic mineral formation, and to maintain a functional DEJ.
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Affiliation(s)
- John D Bartlett
- Department of Cytokine Biology, Forsyth Institute, Cambridge, MA 02142, USA.
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Athanassiou-Papaefthymiou M, Kim D, Harbron L, Papagerakis S, Schnell S, Harada H, Papagerakis P. Molecular and circadian controls of ameloblasts. Eur J Oral Sci 2012; 119 Suppl 1:35-40. [PMID: 22243224 DOI: 10.1111/j.1600-0722.2011.00918.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Stage-specific expression of ameloblast-specific genes is controlled by differential expression of transcription factors. In addition, ameloblasts follow daily rhythms in their main activities (i.e. enamel protein secretion and enamel mineralization). This time-related control is orchestrated by oscillations of clock proteins involved in the regulation of circadian rhythms. Our aim was to identify the potential links between daily rhythms and developmental controls of ameloblast differentiation. The effects of the transcription factors distal-less homeobox 3 (Dlx3) and runt-related transcription factor 2 (Runx2), and the clock gene nuclear receptor subfamily 1, group D, member 1 (Nr1d1), on secretory and maturation ameloblasts [using stage-specific markers amelogenin (Amelx), enamelin (Enam), and kallikrein-related peptidase 4 (Klk4)] were evaluated in the HAT-7 ameloblast cell line. Amelx and Enam steady-state mRNA expression levels were down-regulated in Runx2 over-expressing cells and up-regulated in Dlx3 over-expressing cells. In contrast, Klk4 mRNA was up-regulated by both Dlx3 and Runx2. Furthermore, a temporal and spatial relationship between clock genes and ameloblast differentiation markers was detected. Of interest, clock genes not only affected rhythmic expression of ameloblast-specific genes but also influenced the expression of Runx2. Multiscale mathematical modeling is being explored to further understand the temporal and developmental controls of ameloblast differentiation. Our study provides novel insights into the regulatory mechanisms sustaining ameloblast differentiation.
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Affiliation(s)
- Maria Athanassiou-Papaefthymiou
- Department of Orthodontics and Pediatric Medicine, Center for Computational Medicine and Bioinformatics, University of Michigan Schools of Dentistry and Medicine, Ann Arbor, MI 48109, USA
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Muto T, Miyoshi K, Horiguchi T, Hagita H, Noma T. Novel genetic linkage of rat Sp6 mutation to Amelogenesis imperfecta. Orphanet J Rare Dis 2012; 7:34. [PMID: 22676574 PMCID: PMC3464675 DOI: 10.1186/1750-1172-7-34] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Accepted: 06/07/2012] [Indexed: 11/16/2022] Open
Abstract
Background Amelogenesis imperfecta (AI) is an inherited disorder characterized by abnormal formation of tooth enamel. Although several genes responsible for AI have been reported, not all causative genes for human AI have been identified to date. AMI rat has been reported as an autosomal recessive mutant with hypoplastic AI isolated from a colony of stroke-prone spontaneously hypertensive rat strain, but the causative gene has not yet been clarified. Through a genetic screen, we identified the causative gene of autosomal recessive AI in AMI and analyzed its role in amelogenesis. Methods cDNA sequencing of possible AI-candidate genes so far identified using total RNA of day 6 AMI rat molars identified a novel responsible mutation in specificity protein 6 (Sp6). Genetic linkage analysis was performed between Sp6 and AI phenotype in AMI. To understand a role of SP6 in AI, we generated the transgenic rats harboring Sp6 transgene in AMI (Ami/Ami + Tg). Histological analyses were performed using the thin sections of control rats, AMI, and Ami/Ami + Tg incisors in maxillae, respectively. Results We found the novel genetic linkage between a 2-bp insertional mutation of Sp6 gene and the AI phenotype in AMI rats. The position of mutation was located in the coding region of Sp6, which caused frameshift mutation and disruption of the third zinc finger domain of SP6 with 11 cryptic amino acid residues and a stop codon. Transfection studies showed that the mutant protein can be translated and localized in the nucleus in the same manner as the wild-type SP6 protein. When we introduced the CMV promoter-driven wild-type Sp6 transgene into AMI rats, the SP6 protein was ectopically expressed in the maturation stage of ameloblasts associated with the extended maturation stage and the shortened reduced stage without any other phenotypical changes. Conclusion We propose the addition of Sp6 mutation as a new molecular diagnostic criterion for the autosomal recessive AI patients. Our findings expand the spectrum of genetic causes of autosomal recessive AI and sheds light on the molecular diagnosis for the classification of AI. Furthermore, tight regulation of the temporospatial expression of SP6 may have critical roles in completing amelogenesis.
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Affiliation(s)
- Taro Muto
- Department of Molecular Biology, Institute of Health Biosciences, The University of Tokushima Graduate School, Kuramoto-cho, Japan
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Poché RA, Sharma R, Garcia MD, Wada AM, Nolte MJ, Udan RS, Paik JH, DePinho RA, Bartlett JD, Dickinson ME. Transcription factor FoxO1 is essential for enamel biomineralization. PLoS One 2012; 7:e30357. [PMID: 22291941 PMCID: PMC3265481 DOI: 10.1371/journal.pone.0030357] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 12/14/2011] [Indexed: 01/10/2023] Open
Abstract
The Transforming growth factor β (Tgf-β) pathway, by signaling via the activation of Smad transcription factors, induces the expression of many diverse downstream target genes thereby regulating a vast array of cellular events essential for proper development and homeostasis. In order for a specific cell type to properly interpret the Tgf-β signal and elicit a specific cellular response, cell-specific transcriptional co-factors often cooperate with the Smads to activate a discrete set of genes in the appropriate temporal and spatial manner. Here, via a conditional knockout approach, we show that mice mutant for Forkhead Box O transcription factor FoxO1 exhibit an enamel hypomaturation defect which phenocopies that of the Smad3 mutant mice. Furthermore, we determined that both the FoxO1 and Smad3 mutant teeth exhibit changes in the expression of similar cohort of genes encoding enamel matrix proteins required for proper enamel development. These data raise the possibility that FoxO1 and Smad3 act in concert to regulate a common repertoire of genes necessary for complete enamel maturation. This study is the first to define an essential role for the FoxO family of transcription factors in tooth development and provides a new molecular entry point which will allow researchers to delineate novel genetic pathways regulating the process of biomineralization which may also have significance for studies of human tooth diseases such as amelogenesis imperfecta.
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Affiliation(s)
- Ross A. Poché
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ramaswamy Sharma
- Department of Cytokine Biology, Forsyth Institute, and Department of Developmental Biology, Harvard School of Dental Medicine, Cambridge, Massachusetts, United States of America
| | - Monica D. Garcia
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Aya M. Wada
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Mark J. Nolte
- Department of Genetics, University of Texas M. D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Ryan S. Udan
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ji-Hye Paik
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Ronald A. DePinho
- Departments of Medical Oncology, Medicine, and Genetics, Belfer Institute for Applied Cancer Science, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, United States of America
| | - John D. Bartlett
- Department of Cytokine Biology, Forsyth Institute, and Department of Developmental Biology, Harvard School of Dental Medicine, Cambridge, Massachusetts, United States of America
| | - Mary E. Dickinson
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Lee KE, Lee SK, Jung SE, Song SJ, Cho SH, Lee ZH, Kim JW. A novel mutation in the AMELX gene and multiple crown resorptions. Eur J Oral Sci 2012; 119 Suppl 1:324-8. [DOI: 10.1111/j.1600-0722.2011.00858.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Urzúa B, Ortega-Pinto A, Farias DA, Franco E, Morales-Bozo I, Moncada G, Escobar-Pezoa N, Scholz U, Cifuentes V. A multidisciplinary approach for the diagnosis of hypocalcified amelogenesis imperfecta in two Chilean families. Acta Odontol Scand 2012; 70:7-14. [PMID: 21504268 DOI: 10.3109/00016357.2011.574973] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The purpose of this study was to conduct a multidisciplinary analysis of a specific type of tooth enamel disturbance (amelogenesis imperfecta) affecting two Chilean families to obtain a precise diagnosis and to investigate possible underlying mutations. MATERIALS AND METHODS Two non-related families affected with amelogenesis imperfecta were evaluated with clinical, radiographic and histopathological methods. Furthermore, pedigrees of both families were constructed and the presence of eight mutations in the enamelin gene (ENAM) and three mutations in the enamelysin gene (MMP-20) were investigated by PCR and direct sequencing. RESULTS In the two affected patients, the dental malformation presented as soft and easily disintegrated enamel and exposed dark dentin. Neither of the affected individuals presented with a dental and skeletal open bite. Histologically, a high level of an organic matrix with prismatic organization was found. Genetic analysis indicated that the condition is autosomal recessive in one family and either autosomal recessive or due to a new mutation in the other family. Molecular mutational analysis revealed that none of the eight mutations previously described in the ENAM gene or the three mutations in the MMP-20 gene were present in the probands. CONCLUSION A multidisciplinary analysis allowed for a diagnosis of hypocalcified amelogenesis imperfecta, Witkop type III, which was unrelated to previously described mutations in the ENAM or MMP-20 genes.
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Affiliation(s)
- Blanca Urzúa
- Department of Physical and Chemical Sciences, University of Chile, Santiago de Chile, Chile.
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Chan HC, Estrella NMRP, Milkovich RN, Kim JW, Simmer JP, Hu JCC. Target gene analyses of 39 amelogenesis imperfecta kindreds. Eur J Oral Sci 2011; 119 Suppl 1:311-23. [PMID: 22243262 PMCID: PMC3292789 DOI: 10.1111/j.1600-0722.2011.00857.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previously, mutational analyses identified six disease-causing mutations in 24 amelogenesis imperfecta (AI) kindreds. We have since expanded the number of AI kindreds to 39, and performed mutation analyses covering the coding exons and adjoining intron sequences for the six proven AI candidate genes [amelogenin (AMELX), enamelin (ENAM), family with sequence similarity 83, member H (FAM83H), WD repeat containing domain 72 (WDR72), enamelysin (MMP20), and kallikrein-related peptidase 4 (KLK4)] and for ameloblastin (AMBN) (a suspected candidate gene). All four of the X-linked AI families (100%) had disease-causing mutations in AMELX, suggesting that AMELX is the only gene involved in the aetiology of X-linked AI. Eighteen families showed an autosomal-dominant pattern of inheritance. Disease-causing mutations were identified in 12 (67%): eight in FAM83H, and four in ENAM. No FAM83H coding-region or splice-junction mutations were identified in three probands with autosomal-dominant hypocalcification AI (ADHCAI), suggesting that a second gene may contribute to the aetiology of ADHCAI. Six families showed an autosomal-recessive pattern of inheritance, and disease-causing mutations were identified in three (50%): two in MMP20, and one in WDR72. No disease-causing mutations were found in 11 families with only one affected member. We conclude that mutation analyses of the current candidate genes for AI have about a 50% chance of identifying the disease-causing mutation in a given kindred.
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Affiliation(s)
- Hui-Chen Chan
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Ninna M. R. P. Estrella
- Department of Orthodontics and Pediatric Dentistry, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Rachel N. Milkovich
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Jung-Wook Kim
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - James P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Jan C-C. Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
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Mitsiadis TA, Luder HU. Genetic basis for tooth malformations: from mice to men and back again. Clin Genet 2011; 80:319-29. [DOI: 10.1111/j.1399-0004.2011.01762.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Mitsiadis TA, Papagerakis P. Regenerated teeth: the future of tooth replacement? Regen Med 2011; 6:135-9. [PMID: 21391845 DOI: 10.2217/rme.10.101] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Simmer JP, Hu Y, Richardson AS, Bartlett JD, Hu JCC. Why does enamel in Klk4-null mice break above the dentino-enamel junction? Cells Tissues Organs 2011; 194:211-5. [PMID: 21546759 PMCID: PMC3178080 DOI: 10.1159/000324260] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The enamel layerof kallikrein 4 (Klk4)-null mice has a normal thickness and a decussating pattern of enamel rods, but it contains residual enamel proteins, is less highly mineralized, and fractures in its deepest part just above the dentino-enamel junction (DEJ). The plane of fracture is puzzling because the deepest enamel is deposited earliest and, through the action of the secretory stage enamel protease (Mmp20), is the most mature part of the enamel layer at the time of the onset of Klk4 expression. OBJECTIVES To characterize the planes of fracture in Mmp20- and Klk4-null mice and to localize Klk4 expression in developing teeth. METHODS Klk4- and Mmp20-null mice were sacrificed at 7 weeks and their mandibular incisors were characterized by scanning electron microscopy. Klk4(+/)(lac)(Z) mice were mated with Klk4(+/)(lac)(Z) mice. Offspring were genotyped by polymerase chain reaction. Klk4(+/)(+), Klk4(+/)(lac)(Z), and Klk4(lac)(Z/)(lac)(Z) (null) littermates on postnatal days 5, 8, 11, and 14 were processed for β-galactosidase histochemistry. RESULTS The enamel layer fractures at the DEJ in Mmp20-null mice, and fractures occur in enamel above the DEJ in Klk4-null mice. Klk4 is not expressed by secretory-stage ameloblasts, murine odontoblasts beneath the secretory stage, or maturation-stage ameloblasts. Klk4 is specifically expressed by transition and maturation-stage ameloblasts. CONCLUSIONS The breakage of enamel near the DEJ in Klk4-null mice is not due to a failure of odontoblasts to express Klk4, but it relates to a progressive hypomineralization of enamel with depth.
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Affiliation(s)
- James P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Mich
| | - Yuanyuan Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Mich
| | - Amelia S. Richardson
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Mich
| | - John D. Bartlett
- Department of Cytokine Biology, The Forsyth Institute, Cambridge, Mass., USA
| | - Jan C.-C. Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Mich
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Pinky, Naik S, ND S. Amelogenesis Imperfecta: Full Mouth Rehabilitation in Deciduous Dentition. Int J Clin Pediatr Dent 2011; 4:171-5. [PMID: 27672261 PMCID: PMC5030508 DOI: 10.5005/jp-journals-10005-1105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 04/15/2011] [Indexed: 12/01/2022] Open
Abstract
This clinical report describes the oral rehabilitation of a very young child diagnosed with hypoplastic amelogenesis imperfecta. The specific treatment objectives being adequate patient management, eliminate tooth sensitivity while enhancing esthetics, masticatory function and improved self confidence. The treatment included full mouth rehabilitation with stainless steel crowns on posterior teeth and indirect composite veneers on anterior teeth.
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Affiliation(s)
- Pinky
- Senior Lecturer, Department of Pediatric Dentistry, Peoples College of Dental Sciences and Research Center Bhopal, Madhya Pradesh, India
| | - Satyajith Naik
- Professor, Department of Pediatric Dentistry, College of Dental Sciences, Davangere, Karnataka, India
| | - Shashikiran ND
- Dean, Peoples College of Dental Sciences and Research Center, Bhopal, Madhya Pradesh, India
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38
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Bartlett JD, Yamakoshi Y, Simmer JP, Nanci A, Smith CE. MMP20 cleaves E-cadherin and influences ameloblast development. Cells Tissues Organs 2011; 194:222-6. [PMID: 21525715 DOI: 10.1159/000324205] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Dental enamel development occurs in stages as observed by the changing morphology of the ameloblasts that are responsible for enamel formation. During the secretory stage of development, proteins including MMP20 are secreted into the enamel matrix. MMP20 is required for proper enamel formation as mutation of the Mmp20 gene causes autosomal recessive amelogenesis imperfecta. Here, we examined in detail the morphology of the Mmp20-null ameloblast cell layer. Intriguingly, we found that the Mmp20-null mouse secretory stage ameloblasts retract their Tomes' processes as if preparing to enter the maturation stage but later reextend their Tomes' processes as if resuming the secretory stage. We also demonstrated that MMP20 cleaves epithelial cadherin, i.e. E-cadherin. Cadherins are transmembrane proteins with extracellular domains that provide adhesive contacts between neighboring cells. Their intracellular domains bind to the cell cytoskeleton through catenins, including β-catenin. When specific MMPs cleave the cadherin extracellular domain, β-catenin is released and may locate to the cell nucleus as a transcription factor. Therefore, MMP20 may influence ameloblast developmental progression through hydrolysis of cadherin extracellular domains with associated release of transcription factor(s).
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Affiliation(s)
- John D Bartlett
- Department of Cytokine Biology, Forsyth Institute and Department of Developmental Biology, Harvard School of Dental Medicine, Cambridge, Mass., USA.
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39
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Meredith RW, Gatesy J, Cheng J, Springer MS. Pseudogenization of the tooth gene enamelysin (MMP20) in the common ancestor of extant baleen whales. Proc Biol Sci 2011; 278:993-1002. [PMID: 20861053 PMCID: PMC3049022 DOI: 10.1098/rspb.2010.1280] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 08/31/2010] [Indexed: 01/11/2023] Open
Abstract
Whales in the suborder Mysticeti are filter feeders that use baleen to sift zooplankton and small fish from ocean waters. Adult mysticetes lack teeth, although tooth buds are present in foetal stages. Cladistic analyses suggest that functional teeth were lost in the common ancestor of crown-group Mysticeti. DNA sequences for the tooth-specific genes, ameloblastin (AMBN), enamelin (ENAM) and amelogenin (AMEL), have frameshift mutations and/or stop codons in this taxon, but none of these molecular cavities are shared by all extant mysticetes. Here, we provide the first evidence for pseudogenization of a tooth gene, enamelysin (MMP20), in the common ancestor of living baleen whales. Specifically, pseudogenization resulted from the insertion of a CHR-2 SINE retroposon in exon 2 of MMP20. Genomic and palaeontological data now provide congruent support for the loss of enamel-capped teeth on the common ancestral branch of crown-group mysticetes. The new data for MMP20 also document a polymorphic stop codon in exon 2 of the pygmy sperm whale (Kogia breviceps), which has enamel-less teeth. These results, in conjunction with the evidence for pseudogenization of MMP20 in Hoffmann's two-toed sloth (Choloepus hoffmanni), another enamel-less species, support the hypothesis that the only unique, non-overlapping function of the MMP20 gene is in enamel formation.
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Affiliation(s)
| | | | | | - Mark S. Springer
- Department of Biology, University of California, Riverside, CA 92521, USA
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40
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Sharma R, Tye CE, Arun A, MacDonald D, Chatterjee A, Abrazinski T, Everett ET, Whitford GM, Bartlett JD. Assessment of dental fluorosis in Mmp20 +/- mice. J Dent Res 2011; 90:788-92. [PMID: 21386097 DOI: 10.1177/0022034511398868] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The molecular mechanisms that underlie dental fluorosis are poorly understood. The retention of enamel proteins hallmarking fluorotic enamel may result from impaired hydrolysis and/or removal of enamel proteins. Previous studies have suggested that partial inhibition of Mmp20 expression is involved in the etiology of dental fluorosis. Here we ask if mice expressing only one functional Mmp20 allele are more susceptible to fluorosis. We demonstrate that Mmp20 (+/-) mice express approximately half the amount of MMP20 as do wild-type mice. The Mmp20 heterozygous mice have normal-appearing enamel, with Vickers microhardness values similar to those of wild-type control enamel. Therefore, reduced MMP20 expression is not solely responsible for dental fluorosis. With 50-ppm-fluoride (F(-)) treatment ad libitum, the Mmp20 (+/-) mice had F(-) tissue levels similar to those of Mmp20 (+/+) mice. No significant difference in enamel hardness was observed between the F(-)-treated heterozygous and wild-type mice. Interestingly, we did find a small but significant difference in quantitative fluorescence between these two groups, which may be attributable to slightly higher protein content in the Mmp20 (+/-) mouse enamel. We conclude that MMP20 plays a nominal role in dental enamel fluorosis.
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Affiliation(s)
- R Sharma
- Department of Cytokine Biology, The Forsyth Institute, Harvard School of Dental Medicine, Boston, MA 02115, USA
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41
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El-Sayed W, Shore RC, Parry DA, Inglehearn CF, Mighell AJ. Hypomaturation amelogenesis imperfecta due to WDR72 mutations: a novel mutation and ultrastructural analyses of deciduous teeth. Cells Tissues Organs 2010; 194:60-6. [PMID: 21196691 PMCID: PMC3128158 DOI: 10.1159/000322036] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mutations in WDR72 have been identified in autosomal recessive hypomaturation amelogenesis imperfecta (AI). OBJECTIVE to describe a novel WDR72 mutation and report the ultrastructural enamel phenotype associated with a different WDR72 mutation. METHODS A family segregating autosomal recessive hypomaturation AI was recruited, genomic DNA obtained and WDR72 sequenced. Four deciduous teeth from one individual with a previously published WDR72 mutation, extracted as part of clinical care, were subjected to scanning electron microscopy, energy-dispersive X-ray analysis and transverse microradiography. RESULTS A novel homozygous nonsense mutation, R897X, was identified in WDR72 in a family originating from Pakistan. Ultrastructural analysis of enamel from the deciduous teeth of an AI patient with the WDR72 mutation S783X revealed energy-dispersive X-ray analysis spectra with normal carbon and nitrogen peaks, excluding retention of enamel matrix protein. However, transverse microradiography values were significantly lower for affected teeth when compared to normal teeth, consistent with reduced mineralisation. On scanning electron microscopy the enamel rod form observed was normal, yet with inter-rod enamel more prominent than in controls. This appearance was unaltered following incubation with either α-chymotrypsin or lipase. CONCLUSIONS The novel WDR72 mutation described brings the total reported WDR72 mutations to four. Analyses of deciduous tooth enamel in an individual with a homozygous WDR72 mutation identified changes consistent with a late failure of enamel maturation without retention of matrix proteins. The mechanisms by which intracellular WDR72 influences enamel maturation remain unknown.
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Affiliation(s)
- W El-Sayed
- Leeds Dental Institute, University of Leeds, Leeds, UK
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42
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Urzúa B, Ortega-Pinto A, Morales-Bozo I, Rojas-Alcayaga G, Cifuentes V. Defining a new candidate gene for amelogenesis imperfecta: from molecular genetics to biochemistry. Biochem Genet 2010; 49:104-21. [PMID: 21127961 DOI: 10.1007/s10528-010-9392-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 07/23/2010] [Indexed: 10/18/2022]
Abstract
Amelogenesis imperfecta is a group of genetic conditions that affect the structure and clinical appearance of tooth enamel. The types (hypoplastic, hypocalcified, and hypomature) are correlated with defects in different stages of the process of enamel synthesis. Autosomal dominant, recessive, and X-linked types have been previously described. These disorders are considered clinically and genetically heterogeneous in etiology, involving a variety of genes, such as AMELX, ENAM, DLX3, FAM83H, MMP-20, KLK4, and WDR72. The mutations identified within these causal genes explain less than half of all cases of amelogenesis imperfecta. Most of the candidate and causal genes currently identified encode proteins involved in enamel synthesis. We think it is necessary to refocus the search for candidate genes using biochemical processes. This review provides theoretical evidence that the human SLC4A4 gene (sodium bicarbonate cotransporter) may be a new candidate gene.
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Affiliation(s)
- Blanca Urzúa
- Department of Physical and Chemical Sciences, Faculty of Dentistry, University of Chile, Santiago, Chile.
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43
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Abstract
Fluorosed enamel can be porous, mottled, discolored, hypomineralized, and protein-rich if the enamel matrix is not completely removed. Proteolytic processing by matrix metalloproteinase-20 (MMP20) and kallikrein-4 (KLK4) is critical for enamel formation, and homozygous mutation of either protease results in hypomineralized, protein-rich enamel. Herein, we demonstrate that the lysosomal proteinase cathepsin K is expressed in the enamel organ in a developmentally defined manner that suggests a role for cathepsin K in degrading re-absorbed enamel matrix proteins. We therefore asked if fluoride directly inhibits the activity of MMP20, KLK4, dipeptidyl peptidase I (DPPI) (an in vitro activator of KLK4), or cathepsin K. Enzyme kinetics were studied with quenched fluorescent peptides with purified enzyme in the presence of 0-10 mM NaF, and data were fit to Michaelis-Menten curves. Increasing concentrations of known inhibitors showed decreases in enzyme activity. However, concentrations of up to 10 mM NaF had no effect on KLK4, MMP20, DPPI, or cathepsin K activity. Our results show that fluoride does not directly inhibit enamel proteolytic activity.
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Affiliation(s)
- C E Tye
- Department of Cytokine Biology, The Forsyth Institute, Harvard School of Dental Medicine, Boston, MA 02115, USA
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44
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Deshpande AS, Fang PA, Simmer JP, Margolis HC, Beniash E. Amelogenin-collagen interactions regulate calcium phosphate mineralization in vitro. J Biol Chem 2010; 285:19277-87. [PMID: 20404336 DOI: 10.1074/jbc.m109.079939] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Collagen and amelogenin are two major extracellular organic matrix proteins of dentin and enamel, the mineralized tissues comprising a tooth crown. They both are present at the dentin-enamel boundary (DEB), a remarkably robust interface holding dentin and enamel together. It is believed that interactions of dentin and enamel protein assemblies regulate growth and structural organization of mineral crystals at the DEB, leading to a continuum at the molecular level between dentin and enamel organic and mineral phases. To gain insight into the mechanisms of the DEB formation and structural basis of its mechanical resiliency we have studied the interactions between collagen fibrils, amelogenin assemblies, and forming mineral in vitro, using electron microscopy. Our data indicate that collagen fibrils guide assembly of amelogenin into elongated chain or filament-like structures oriented along the long axes of the fibrils. We also show that the interactions between collagen fibrils and amelogenin-calcium phosphate mineral complexes lead to oriented deposition of elongated amorphous mineral particles along the fibril axes, triggering mineralization of the bulk of collagen fibril. The resulting structure was similar to the mineralized collagen fibrils found at the DEB, with arrays of smaller well organized crystals inside the collagen fibrils and bundles of larger crystals on the outside of the fibrils. These data suggest that interactions between collagen and amelogenin might play an important role in the formation of the DEB providing structural continuity between dentin and enamel.
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Affiliation(s)
- Atul S Deshpande
- Department of Oral Biology, Center for Craniofacial Regeneration, University of Pittsburgh School of Dental Medicine, Pittsburgh, Pennsylvania 15261, USA
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45
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Lee SK, Seymen F, Kang HY, Lee KE, Gencay K, Tuna B, Kim JW. MMP20 hemopexin domain mutation in amelogenesis imperfecta. J Dent Res 2010; 89:46-50. [PMID: 19966041 DOI: 10.1177/0022034509352844] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Proteolytic enzymes serve important functions during dental enamel formation, and mutations in the kallikrein 4 (KLK4) and enamelysin (MMP20) genes cause autosomal-recessive amelogenesis imperfecta (ARAI). So far, only 1 KLK4 and 3 MMP20 mutations have been reported in ARAI kindreds. To determine whether ARAI in a family with a hypomaturation-type enamel defect is caused by mutations in the genes encoding enamel proteolytic enzymes, we performed mutational analysis on candidate genes. Mutational and haplotype analyses revealed an ARAI-causing point mutation (c.910G>A, p.A304T) in exon 6 of MMP20 that results in a single amino acid substitution in the hemopexin domain. Western blot analysis showed decreased expression of the mutant protein, but zymogram analysis demonstrated that this mutant was a functional protein. The proband and an affected brother were homozygous for the mutation, and both unaffected parents were carriers. The enamel of newly erupted teeth had normal thickness, but was chalky white and became darker with age.
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Affiliation(s)
- S-K Lee
- Department of Cell and Developmental Biology, Dental Research Institute and BK21 Program, School of Dentistry, Seoul National University, 275-1 Yongon-dong, Chongno-gu, Seoul 110-768, Korea
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46
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Abstract
Metalloproteases comprise a heterogeneous group of proteolytic enzymes whose main characteristic is the utilization of a metal ion to polarize a water molecule and perform hydrolytic reactions. These enzymes represent the most densely populated catalytic class of proteases in many organisms and play essential roles in multiple biological processes. In this chapter, we will first present a general description of the complexity of metalloproteases in the context of the degradome, which is defined as the complete set of protease genes encoded by the genome of a certain organism. We will also discuss the functional relevance of these enzymes in a large variety of biological and pathological conditions. Finally, we will analyze in more detail three families of metalloproteases: ADAMs (a disintegrin and metalloproteinase), ADAMTSs (ADAMs with thrombospondin domains), and MMPs (matrix metalloproteinases) which have a growing relevance in a number of human pathologies including cancer, arthritis, neurodegenerative disorders, and cardiovascular diseases.
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Affiliation(s)
- Alejandro P Ugalde
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Oviedo, Spain
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47
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Matrix metalloproteinases: Evolution, gene regulation and functional analysis in mouse models. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:3-19. [DOI: 10.1016/j.bbamcr.2009.07.004] [Citation(s) in RCA: 379] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 07/11/2009] [Accepted: 07/14/2009] [Indexed: 12/19/2022]
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48
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El-Sayed W, Parry DA, Shore RC, Ahmed M, Jafri H, Rashid Y, Al-Bahlani S, Al Harasi S, Kirkham J, Inglehearn CF, Mighell AJ. Mutations in the beta propeller WDR72 cause autosomal-recessive hypomaturation amelogenesis imperfecta. Am J Hum Genet 2009; 85:699-705. [PMID: 19853237 PMCID: PMC2775821 DOI: 10.1016/j.ajhg.2009.09.014] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/22/2009] [Accepted: 09/25/2009] [Indexed: 11/26/2022] Open
Abstract
Healthy dental enamel is the hardest and most highly mineralized human tissue. Though acellular, nonvital, and without capacity for turnover or repair, it can nevertheless last a lifetime. Amelogenesis imperfecta (AI) is a collective term for failure of normal enamel development, covering diverse clinical phenotypes that typically show Mendelian inheritance patterns. One subset, known as hypomaturation AI, is characterised by near-normal volumes of organic enamel matrix but with weak, creamy-brown opaque enamel that fails prematurely after tooth eruption. Mutations in genes critical to enamel matrix formation have been documented, but current understanding of other key events in enamel biomineralization is limited. We investigated autosomal-recessive hypomaturation AI in a consanguineous Pakistani family. A whole-genome SNP autozygosity screen identified a locus on chromosome 15q21.3. Sequencing candidate genes revealed a point mutation in the poorly characterized WDR72 gene. Screening of WDR72 in a panel of nine additional hypomaturation AI families revealed the same mutation in a second, apparently unrelated, Pakistani family and two further nonsense mutations in Omani families. Immunohistochemistry confirmed intracellular localization in maturation-stage ameloblasts. WDR72 function is unknown, but as a putative β propeller is expected to be a scaffold for protein-protein interactions. The nearest homolog, WDR7, is involved in vesicle mobilization and Ca2+-dependent exocytosis at synapses. Vesicle trafficking is important in maturation-stage ameloblasts with respect to secretion into immature enamel and removal of cleaved enamel matrix proteins via endocytosis. This raises the intriguing possibility that WDR72 is critical to ameloblast vesicle turnover during enamel maturation.
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Becerik S, Cogulu D, Emingil G, Han T, Hart PS, Hart TC. Exclusion of candidate genes in seven Turkish families with autosomal recessive amelogenesis imperfecta. Am J Med Genet A 2009; 149A:1392-8. [PMID: 19530186 DOI: 10.1002/ajmg.a.32885] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Amelogenesis imperfectas (AI) are a group of inherited defects of dental enamel formation that show both clinical and genetic heterogeneity. Seven Turkish families segregating autosomal recessive AI (ARAI) were evaluated for evidence of a genetic etiology of AI for the seven major candidate gene loci (AMBN, AMELX, ENAM, FAM83H, KLK4, MMP20, and TUFT1). Dental and periodontal characteristics of the affected members of these families were also described. The mean scores of DMFS and dfs indices were 9.7 and 9.6, respectively. The mean PPD was 2.2 mm and the percentage of the sites with plaque and BOP were 87.8% and 72.4%, respectively. The exons and intron/exon junctions of the candidate genes were sequenced and no gene mutations were identified in any individuals. These findings support the existence of an additional gene(s) that are etiologic for ARAI in these families.
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Affiliation(s)
- Sema Becerik
- Department of Periodontology, School of Dentistry, Ege University, Izmir, Turkey.
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50
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Simmer JP, Hu Y, Lertlam R, Yamakoshi Y, Hu JCC. Hypomaturation enamel defects in Klk4 knockout/LacZ knockin mice. J Biol Chem 2009; 284:19110-21. [PMID: 19578120 DOI: 10.1074/jbc.m109.013623] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kallikrein 4 (Klk4) is believed to play an essential role in enamel biomineralization, because defects in KLK4 cause hypomaturation amelogenesis imperfecta. We used gene targeting to generate a knockin mouse that replaces the Klk4 gene sequence, starting at the translation initiation site, with a lacZ reporter gene. Correct targeting of the transgene was confirmed by Southern blot and PCR analyses. Histochemical X-gal (5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside) staining demonstrated expression of beta-galactosidase in maturation stage ameloblasts. No X-gal staining was observed in secretory stage ameloblasts or in odontoblasts. Retained enamel proteins were observed in the maturation stage enamel of the Klk4 null mouse, but not in the Klk4 heterozygous or wild-type mice. The enamel layer in the Klk4 null mouse was normal in thickness and contained decussating enamel rods but was rapidly abraded following weaning, despite the mice being maintained on soft chow. In function the enamel readily fractured within the initial rod and interrod enamel above the parallel enamel covering the dentino-enamel junction. Despite the lack of Klk4 and the retention of enamel proteins, significant levels of crystal maturation occurred (although delayed), and the enamel achieved a mineral density in some places greater than that detected in bone and dentin. An important finding was that individual enamel crystallites of erupted teeth failed to grow together, interlock, and function as a unit. Instead, individual crystallites seemed to spill out of the enamel when fractured. These results demonstrate that Klk4 is essential for the removal of enamel proteins and the proper maturation of enamel crystals.
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Affiliation(s)
- James P Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48108, USA.
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