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Wang YL, Lin HC, Liang T, Lin JY, Simmer J, Hu JC, Wang SK. ENAM Mutations Can Cause Hypomaturation Amelogenesis Imperfecta. J Dent Res 2024; 103:662-671. [PMID: 38716742 PMCID: PMC11122092 DOI: 10.1177/00220345241236695] [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] [Indexed: 05/12/2024] Open
Abstract
Amelogenesis imperfecta (AI) is a diverse group of inherited diseases featured by various presentations of enamel malformations that are caused by disturbances at different stages of enamel formation. While hypoplastic AI suggests a thickness defect of enamel resulting from aberrations during the secretory stage of amelogenesis, hypomaturation AI indicates a deficiency of enamel mineralization and hardness established at the maturation stage. Mutations in ENAM, which encodes the largest enamel matrix protein, enamelin, have been demonstrated to cause generalized or local hypoplastic AI. Here, we characterized 2 AI families with disparate hypoplastic and hypomaturation enamel defects and identified 2 distinct indel mutations at the same location of ENAM, c588+1del and c.588+1dup. Minigene splicing assays demonstrated that they caused frameshifts and truncation of ENAM proteins, p.Asn197Ilefs*81 and p.Asn197Glufs*25, respectively. In situ hybridization of Enam on mouse mandibular incisors confirmed its restricted expression in secretory stage ameloblasts and suggested an indirect pathogenic mechanism underlying hypomaturation AI. In silico analyses indicated that these 2 truncated ENAMs might form amyloid structures and cause protein aggregation with themselves and with wild-type protein through the added aberrant region at their C-termini. Consistently, protein secretion assays demonstrated that the truncated proteins cannot be properly secreted and impede secretion of wild-type ENAM. Moreover, compared to the wild-type, overexpression of the mutant proteins significantly increased endoplasmic reticulum stress and upregulated the expression of unfolded protein response (UPR)-related genes and TNFRSF10B, a UPR-controlled proapoptotic gene. Caspase, terminal deoxynucleotidyl transferase UTP nick-end labeling (TUNEL), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays further revealed that both truncated proteins, especially p.Asn197Ilefs*81, induced cell apoptosis and decreased cell survival, suggesting that the 2 ENAM mutations cause AI through ameloblast cell pathology and death rather than through a simple loss of function. This study demonstrates that an ENAM mutation can lead to generalized hypomaturation enamel defects and suggests proteinopathy as a potential pathogenesis for ENAM-associated AI.
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Affiliation(s)
- Y.-L. Wang
- Department of Dentistry, National Taiwan University School of Dentistry, Taipei City, Taiwan
- Department of Pediatric Dentistry, National Taiwan University Children’s Hospital, Taipei City, Taiwan
| | - H.-C. Lin
- Department of Dentistry, National Taiwan University School of Dentistry, Taipei City, Taiwan
| | - T. Liang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - J.C.-Y. Lin
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, National Defense Medical University, Taipei City, Taiwan
| | - J.P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - J.C.-C. Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - S.-K. Wang
- Department of Dentistry, National Taiwan University School of Dentistry, Taipei City, Taiwan
- Department of Pediatric Dentistry, National Taiwan University Children’s Hospital, Taipei City, Taiwan
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2
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Hany U, Watson CM, Liu L, Smith CEL, Harfoush A, Poulter JA, Nikolopoulos G, Balmer R, Brown CJ, Patel A, Simmonds J, Charlton R, Acosta de Camargo MG, Rodd HD, Jafri H, Antanaviciute A, Moffat M, Al-Jawad M, Inglehearn CF, Mighell AJ. Heterozygous COL17A1 variants are a frequent cause of amelogenesis imperfecta. J Med Genet 2024; 61:347-355. [PMID: 37979963 PMCID: PMC10982616 DOI: 10.1136/jmg-2023-109510] [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: 07/13/2023] [Accepted: 10/17/2023] [Indexed: 11/20/2023]
Abstract
BACKGROUND Collagen XVII is most typically associated with human disease when biallelic COL17A1 variants (>230) cause junctional epidermolysis bullosa (JEB), a rare, genetically heterogeneous, mucocutaneous blistering disease with amelogenesis imperfecta (AI), a developmental enamel defect. Despite recognition that heterozygous carriers in JEB families can have AI, and that heterozygous COL17A1 variants also cause dominant corneal epithelial recurrent erosion dystrophy (ERED), the importance of heterozygous COL17A1 variants causing dominant non-syndromic AI is not widely recognised. METHODS Probands from an AI cohort were screened by single molecule molecular inversion probes or targeted hybridisation capture (both a custom panel and whole exome sequencing) for COL17A1 variants. Patient phenotypes were assessed by clinical examination and analyses of affected teeth. RESULTS Nineteen unrelated probands with isolated AI (no co-segregating features) had 17 heterozygous, potentially pathogenic COL17A1 variants, including missense, premature termination codons, frameshift and splice site variants in both the endo-domains and the ecto-domains of the protein. The AI phenotype was consistent with enamel of near normal thickness and variable focal hypoplasia with surface irregularities including pitting. CONCLUSION These results indicate that COL17A1 variants are a frequent cause of dominantly inherited non-syndromic AI. Comparison of variants implicated in AI and JEB identifies similarities in type and distribution, with five identified in both conditions, one of which may also cause ERED. Increased availability of genetic testing means that more individuals will receive reports of heterozygous COL17A1 variants. We propose that patients with isolated AI or ERED, due to COL17A1 variants, should be considered as potential carriers for JEB and counselled accordingly, reflecting the importance of multidisciplinary care.
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Affiliation(s)
- Ummey Hany
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
| | - Christopher M Watson
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
- North East and Yorkshire Genomic Laboratory Hub, Central Lab, St. James's University Hospital, Leeds, UK
| | - Lu Liu
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - Claire E L Smith
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
| | - Asmaa Harfoush
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - James A Poulter
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
| | - Georgios Nikolopoulos
- Institute for Fundamental Biomedical Research, B.S.R.C. 'Alexander Fleming', Vari, Attica, Greece
| | - Richard Balmer
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - Catriona J Brown
- Birmingham Dental Hospital, Mill Pool Way, Edgbaston, Birmingham, UK
| | - Anesha Patel
- LCRN West Midlands Core Team, NIHR Clinical Research Network (CRN), Birmingham Research Park (West Wing), Vincent Drive, Edgbaston, Birmingham, UK
| | - Jenny Simmonds
- North East and Yorkshire Genomic Laboratory Hub, Central Lab, St. James's University Hospital, Leeds, UK
| | - Ruth Charlton
- North East and Yorkshire Genomic Laboratory Hub, Central Lab, St. James's University Hospital, Leeds, UK
| | | | - Helen D Rodd
- Academic Unit of Oral Health Dentistry and Society, School of Clinical Dentistry, University of Sheffield, Sheffield, UK
| | - Hussain Jafri
- Fatima Jinnah Medical University, Punjab Thalassaemia and Other Genetic Disorders Prevention and Research Institute, Lahore, Pakistan
| | | | - Michelle Moffat
- Paediatric Dentistry, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Maisoon Al-Jawad
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - Chris F Inglehearn
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
| | - Alan J Mighell
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
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Hany U, Watson C, Liu L, Nikolopoulos G, Smith C, Poulter J, Brown C, Patel A, Rodd H, Balmer R, Harfoush A, Al-Jawad M, Inglehearn C, Mighell A. Novel Ameloblastin Variants, Contrasting Amelogenesis Imperfecta Phenotypes. J Dent Res 2024; 103:22-30. [PMID: 38058155 PMCID: PMC10734210 DOI: 10.1177/00220345231203694] [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] [Indexed: 12/08/2023] Open
Abstract
Amelogenesis imperfecta (AI) comprises a group of rare, inherited disorders with abnormal enamel formation. Ameloblastin (AMBN), the second most abundant enamel matrix protein (EMP), plays a critical role in amelogenesis. Pathogenic biallelic loss-of-function AMBN variants are known to cause recessive hypoplastic AI. A report of a family with dominant hypoplastic AI attributed to AMBN missense change p.Pro357Ser, together with data from animal models, suggests that the consequences of AMBN variants in human AI remain incompletely characterized. Here we describe 5 new pathogenic AMBN variants in 11 individuals with AI. These fall within 3 groups by phenotype. Group 1, consisting of 6 families biallelic for combinations of 4 different variants, have yellow hypoplastic AI with poor-quality enamel, consistent with previous reports. Group 2, with 2 families, appears monoallelic for a variant shared with group 1 and has hypomaturation AI of near-normal enamel volume with pitting. Group 3 includes 3 families, all monoallelic for a fifth variant, which are affected by white hypoplastic AI with a thin intact enamel layer. Three variants, c.209C>G; p.(Ser70*) (groups 1 and 2), c.295T>C; p.(Tyr99His) (group 1), and c.76G>A; p.(Ala26Thr) (group 3) were identified in multiple families. Long-read AMBN locus sequencing revealed these variants are on the same conserved haplotype, implying they originate from a common ancestor. Data presented therefore provide further support for possible dominant as well as recessive inheritance for AMBN-related AI and for multiple contrasting phenotypes. In conclusion, our findings suggest pathogenic AMBN variants have a more complex impact on human AI than previously reported.
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Affiliation(s)
- U. Hany
- Leeds Institute of Medical Research, University of Leeds, St. James’s University Hospital, Leeds, UK
| | - C.M. Watson
- Leeds Institute of Medical Research, University of Leeds, St. James’s University Hospital, Leeds, UK
- North East and Yorkshire Genomic Laboratory Hub, Central Lab, St. James’s University Hospital, Leeds, UK
| | - L. Liu
- Leeds Institute of Medical Research, University of Leeds, St. James’s University Hospital, Leeds, UK
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - G. Nikolopoulos
- Leeds Institute of Medical Research, University of Leeds, St. James’s University Hospital, Leeds, UK
| | - C.E.L. Smith
- Leeds Institute of Medical Research, University of Leeds, St. James’s University Hospital, Leeds, UK
| | - J.A. Poulter
- Leeds Institute of Medical Research, University of Leeds, St. James’s University Hospital, Leeds, UK
| | - C.J. Brown
- Birmingham Dental Hospital, Mill Pool Way, Edgbaston, Birmingham, UK
| | - A. Patel
- LCRN West Midlands Core Team, NIHR Clinical Research Network (CRN), Birmingham Research Park (West Wing), Edgbaston, Birmingham, UK
| | - H.D. Rodd
- Academic Unit of Oral Health Dentistry and Society, School of Clinical Dentistry, University of Sheffield, Sheffield, S Yorks, UK
| | - R. Balmer
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - A. Harfoush
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - M. Al-Jawad
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - C.F. Inglehearn
- Leeds Institute of Medical Research, University of Leeds, St. James’s University Hospital, Leeds, UK
| | - A.J. Mighell
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
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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: 15] [Impact Index Per Article: 15.0] [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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Bui AT, Lukashova L, Verdelis K, Vasquez B, Bhogadi L, Gabe CM, Margolis HC, Beniash E. Identification of stages of amelogenesis in the continuously growing mandiblular incisor of C57BL/6J male mice throughout life using molar teeth as landmarks. Front Physiol 2023; 14:1144712. [PMID: 36846326 PMCID: PMC9950101 DOI: 10.3389/fphys.2023.1144712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 01/31/2023] [Indexed: 02/12/2023] Open
Abstract
Continuously growing mouse incisors are widely used to study amelogenesis, since all stages of this process (i.e., secretory, transition and maturation) are present in a spatially determined sequence at any given time. To study biological changes associated with enamel formation, it is important to develop reliable methods for collecting ameloblasts, the cells that regulate enamel formation, from different stages of amelogenesis. Micro-dissection, the key method for collecting distinct ameloblast populations from mouse incisors, relies on positions of molar teeth as landmarks for identifying critical stages of amelogenesis. However, the positions of mandibular incisors and their spatial relationships with molars change with age. Our goal was to identify with high precision these relationships throughout skeletal growth and in older, skeletally mature animals. Mandibles from 2, 4, 8, 12, 16, and 24-week-old, and 18-month-old C57BL/6J male mice, were collected and studied using micro-CT and histology to obtain incisal enamel mineralization profiles and to identify corresponding changes in ameloblast morphology during amelogenesis with respect to positions of molars. As reported here, we have found that throughout active skeletal growth (weeks 2-16) the apices of incisors and the onset of enamel mineralization move distally relative to molar teeth. The position of the transition stage also moves distally. To test the accuracy of the landmarks, we micro-dissected enamel epithelium from mandibular incisors of 12-week-old animals into five segments, including 1) secretory, 2) late secretory - transition - early maturation, 3) early maturation, 4) mid-maturation and 5) late maturation. Isolated segments were pooled and subjected to expression analyses of genes encoding key enamel matrix proteins (EMPs), Amelx, Enam, and Odam, using RT-qPCR. Amelx and Enam were strongly expressed during the secretory stage (segment 1), while their expression diminished during transition (segment 2) and ceased in maturation (segments 3, 4, and 5). In contrast, Odam's expression was very low during secretion and increased dramatically throughout transition and maturation stages. These expression profiles are consistent with the consensus understanding of enamel matrix proteins expression. Overall, our results demonstrate the high accuracy of our landmarking method and emphasize the importance of selecting age-appropriate landmarks for studies of amelogenesis in mouse incisors.
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Affiliation(s)
- Ai Thu Bui
- Department of Oral and Craniofacial Sciences, University of Pittsburgh School of Dental Medicine (UPSDM), Pittsburgh, PA, United States,Center for Craniofacial Regeneration, UPSDM, Pittsburgh, PA, United States
| | - Lyudmila Lukashova
- Center for Craniofacial Regeneration, UPSDM, Pittsburgh, PA, United States
| | - Kostas Verdelis
- Center for Craniofacial Regeneration, UPSDM, Pittsburgh, PA, United States,Department of Endodontics, UPSDM, Pittsburgh, PA, United States
| | - Brent Vasquez
- Department of Oral and Craniofacial Sciences, University of Pittsburgh School of Dental Medicine (UPSDM), Pittsburgh, PA, United States
| | - Lasya Bhogadi
- Department of Oral and Craniofacial Sciences, University of Pittsburgh School of Dental Medicine (UPSDM), Pittsburgh, PA, United States
| | - Claire M. Gabe
- Department of Oral and Craniofacial Sciences, University of Pittsburgh School of Dental Medicine (UPSDM), Pittsburgh, PA, United States,Center for Craniofacial Regeneration, UPSDM, Pittsburgh, PA, United States
| | - Henry C. Margolis
- Department of Oral and Craniofacial Sciences, University of Pittsburgh School of Dental Medicine (UPSDM), Pittsburgh, PA, United States,Center for Craniofacial Regeneration, UPSDM, Pittsburgh, PA, United States,Department of Periodontics and Preventive Dentistry, UPSDM, Pittsburgh, PA, United States
| | - Elia Beniash
- Department of Oral and Craniofacial Sciences, University of Pittsburgh School of Dental Medicine (UPSDM), Pittsburgh, PA, United States,Center for Craniofacial Regeneration, UPSDM, Pittsburgh, PA, United States,*Correspondence: Elia Beniash,
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Kegulian NC, Langen R, Moradian-Oldak J. The Dynamic Interactions of a Multitargeting Domain in Ameloblastin Protein with Amelogenin and Membrane. Int J Mol Sci 2023; 24:3484. [PMID: 36834897 PMCID: PMC9966149 DOI: 10.3390/ijms24043484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/28/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
The enamel matrix protein Ameloblastin (Ambn) has critical physiological functions, including regulation of mineral formation, cell differentiation, and cell-matrix adhesion. We investigated localized structural changes in Ambn during its interactions with its targets. We performed biophysical assays and used liposomes as a cell membrane model. The xAB2N and AB2 peptides were rationally designed to encompass regions of Ambn that contained self-assembly and helix-containing membrane-binding motifs. Electron paramagnetic resonance (EPR) on spin-labeled peptides showed localized structural gains in the presence of liposomes, amelogenin (Amel), and Ambn. Vesicle clearance and leakage assays indicated that peptide-membrane interactions were independent from peptide self-association. Tryptophan fluorescence and EPR showed competition between Ambn-Amel and Ambn-membrane interactions. We demonstrate localized structural changes in Ambn upon interaction with different targets via a multitargeting domain, spanning residues 57 to 90 of mouse Ambn. Structural changes of Ambn following its interaction with different targets have relevant implications for the multifunctionality of Ambn in enamel formation.
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Affiliation(s)
- Natalie C. Kegulian
- Center for Craniofacial Molecular Biology, Department of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA
| | - Ralf Langen
- Department of Neuroscience and Physiology, Department of Biochemistry and Molecular Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Janet Moradian-Oldak
- Center for Craniofacial Molecular Biology, Department of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA
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7
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Li P, Zeng B, Xie W, Xiao X, Lin L, Yu D, Zhao W. Enamel Structure Defects in Kdf1 Missense Mutation Knock-in Mice. Biomedicines 2023; 11:biomedicines11020482. [PMID: 36831017 PMCID: PMC9953722 DOI: 10.3390/biomedicines11020482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023] Open
Abstract
The Keratinocyte differentiation factor 1 (KDF1) is reported to take part in tooth formation in humans, but the dental phenotype of Kdf1 mutant mice has not been understood. Additionally, the role of the KDF1 gene in dental hard tissue development is rarely known. In this study, we constructed a Kdf1 missense mutation knock-in mouse model through CRISPR/Cas9 gene-editing technology. Enamel samples from wildtypes (WT) and Kdf1 homozygous mutants (HO) were examined using micro-computed tomography (micro-CT), scanning electron microscopy (SEM), an atomic force microscope (AFM) and Raman microspectroscopy. The results showed that a novel Kdf1 missense mutation (c. 908G>C, p.R303P) knock-in mice model was constructed successfully. The enamel of HO mice incisors appeared chalky and defective, exposing the rough interior of the inner enamel and dentin. Micro-CT showed that HO mice had lower volume and mineral density in their tooth enamel. In addition, declined thickness was found in the unerupted enamel layer of incisors in the HO mice. Using SEM and AFM, it was found that enamel prisms in HO mice enamel were abnormally and variously shaped with loose decussating crystal arrangement, meanwhile the enamel rods were partially fused and collapsed, accompanied by large gaps. Furthermore, misshapen nanofibrous apatites were disorderly combined with each other. Raman microspectroscopy revealed a compromised degree of order within the crystals in the enamel after the Kdf1 mutation. To conclude, we identified enamel structure defects in the Kdf1 missense mutation knock-in mice, which displayed fragmentary appearance, abnormally shaped prism structure, decreased mineral density, altered crystal ordering degree and chemical composition of the enamel layer. This may support the potential role of the KDF1 gene in the natural development of enamel.
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8
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Dong C, Lamichhane B, Yamazaki H, Vasquez B, Wang J, Zhang Y, Feng JQ, Margolis HC, Beniash E, Wang X. The phosphorylation of serine 55 in enamelin is essential for murine amelogenesis. Matrix Biol 2022; 111:245-263. [PMID: 35820561 PMCID: PMC11244640 DOI: 10.1016/j.matbio.2022.07.001] [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: 11/09/2021] [Revised: 06/02/2022] [Accepted: 07/07/2022] [Indexed: 10/17/2022]
Abstract
Amelogenesis imperfecta (AI) is an inherited developmental enamel defect affecting tooth masticatory function, esthetic appearance, and the well-being of patients. As one of the major enamel matrix proteins (EMPs), enamelin (ENAM) has three serines located in Ser-x-Glu (S-x-E) motifs, which are potential phosphorylation sites for the Golgi casein kinase FAM20C. Defects in FAM20C have similarly been associated with AI. In our previous study of EnamRgsc514 mice, the Glu57 in the S55-X56-E57 motif was mutated into Gly, which was expected to cause a phosphorylation failure of Ser55 because Ser55 cannot be recognized by FAM20C. The severe enamel defects in ENAMRgsc514 mice reminiscent of Enam-knockout mouse enamel suggested a potentially important role of Ser55 phosphorylation in ENAM function. However, the enamel defects and ENAM dysfunction may also be attributed to distinct physicochemical differences between Glu57 and Gly57. To clarify the significance of Ser55 phosphorylation to ENAM function, we generated two lines of Enam knock-in mice using CRISPR-Cas9 method to eliminate or mimic the phosphorylation state of Ser55 by substituting it with Ala55 or Asp55 (designated as S55A or S55D), respectively. The teeth of 6-day or 4-week-old mice were subjected to histology, micro-CT, SEM, TEM, immunohistochemistry, and mass spectrometry analyses to characterize the morphological, microstructural and proteomic changes in ameloblasts, enamel matrix and enamel rods. Our results showed that the enamel formation and EMP expression in S55D heterozygotes (Het) were less disturbed than those in S55A heterozygotes, while both homozygotes (Homo) had no mature enamel formation. Proteomic analysis revealed alterations of enamel matrix biosynthetic and mineralization processes in S55A Hets. Our present findings indicate that Asp55 substitution partially mimics the phosphorylation state of Ser55 in ENAM. Ser55 phosphorylation is essential for ENAM function during amelogenesis.
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Affiliation(s)
- Changchun Dong
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Bikash Lamichhane
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Hajime Yamazaki
- Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Brent Vasquez
- Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jingya Wang
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Yongxu Zhang
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Jian Q Feng
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Henry C Margolis
- Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States; Department of Periodontics and Preventive Dentistry, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Elia Beniash
- Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xiaofang Wang
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States.
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Missense mutation of MAL causes a rare leukodystrophy similar to Pelizaeus-Merzbacher disease. Eur J Hum Genet 2022; 30:860-864. [PMID: 35217805 PMCID: PMC9259702 DOI: 10.1038/s41431-022-01050-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 01/03/2022] [Accepted: 01/18/2022] [Indexed: 11/08/2022] Open
Abstract
Leukodystrophies are a heterogenous group of genetic disorders, characterised by abnormal development of cerebral white matter. Pelizaeus-Merzbacher disease is caused by mutations in PLP1, encoding major myelin-resident protein required for myelin sheath assembly. We report a missense variant p.(Ala109Asp) in MAL as causative for a rare, hypomyelinating leukodystrophy similar to Pelizaeus-Merzbacher disease. MAL encodes a membrane proteolipid that directly interacts with PLP1, ensuring correct distribution during myelin assembly. In contrast to wild-type MAL, mutant MAL was retained in the endoplasmic reticulum but was released following treatment with 4-phenylbutyrate. Proximity-dependent identification of wild-type MAL interactants implicated post-Golgi vesicle-mediated protein transport and protein localisation to membranes, whereas mutant MAL interactants suggested unfolded protein responses. Our results suggest that mislocalisation of MAL affects PLP1 distribution, consistent with known pathomechanisms for hypomyelinating leukodystrophies.
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Loss of BMP2 and BMP4 Signaling in the Dental Epithelium Causes Defective Enamel Maturation and Aberrant Development of Ameloblasts. Int J Mol Sci 2022; 23:ijms23116095. [PMID: 35682776 PMCID: PMC9180982 DOI: 10.3390/ijms23116095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/18/2022] [Accepted: 05/25/2022] [Indexed: 12/10/2022] Open
Abstract
BMP signaling is crucial for differentiation of secretory ameloblasts, the cells that secrete enamel matrix. However, whether BMP signaling is required for differentiation of maturation-stage ameloblasts (MA), which are instrumental for enamel maturation into hard tissue, is hitherto unknown. To address this, we used an in vivo genetic approach which revealed that combined deactivation of the Bmp2 and Bmp4 genes in the murine dental epithelium causes development of dysmorphic and dysfunctional MA. These fail to exhibit a ruffled apical plasma membrane and to reabsorb enamel matrix proteins, leading to enamel defects mimicking hypomaturation amelogenesis imperfecta. Furthermore, subsets of mutant MA underwent pathological single or collective cell migration away from the ameloblast layer, forming cysts and/or exuberant tumor-like and gland-like structures. Massive apoptosis in the adjacent stratum intermedium and the abnormal cell-cell contacts and cell-matrix adhesion of MA may contribute to this aberrant behavior. The mutant MA also exhibited severely diminished tissue non-specific alkaline phosphatase activity, revealing that this enzyme’s activity in MA crucially depends on BMP2 and BMP4 inputs. Our findings show that combined BMP2 and BMP4 signaling is crucial for survival of the stratum intermedium and for proper development and function of MA to ensure normal enamel maturation.
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11
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Liang T, Xu Q, Zhang H, Wang S, Diekwisch TGH, Qin C, Lu Y. Enamel Defects Associated With Dentin Sialophosphoprotein Mutation in Mice. Front Physiol 2021; 12:724098. [PMID: 34630144 PMCID: PMC8497714 DOI: 10.3389/fphys.2021.724098] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/31/2021] [Indexed: 12/04/2022] Open
Abstract
Dentin sialophosphoprotein (DSPP) is an extracellular matrix protein that is highly expressed in odontoblasts, but only transiently expressed in presecretory ameloblasts during tooth development. We previously generated a knockin mouse model expressing a mouse equivalent (DSPP, p.P19L) of human mutant DSPP (p.P17L; referred to as “DsppP19L/+”), and reported that DsppP19L/+ and DsppP19L/P19L mice manifested a dentin phenotype resembling human dentinogenesis imperfecta (DGI). In this study, we analyzed pathogenic effects of mutant P19L-DSPP on enamel development in DsppP19L/+ and DsppP19L/P19L mice. Micro-Computed Tomography (μCT) analyses of 7-week-old mouse mandibular incisors showed that DsppP19L/P19L mice had significantly decreased enamel volume and/or enamel density at different stages of amelogenesis examined. Acid-etched scanning electron microscopy (SEM) analyses of mouse incisors demonstrated that, at the mid-late maturation stage of amelogenesis, the enamel of wild-type mice already had apparent decussating pattern of enamel rods, whereas only minute particulates were found in DsppP19L/+ mice, and no discernible structures in DsppP19L/P19L mouse enamel. However, by the time that incisor enamel was about to erupt into oral cavity, distinct decussating enamel rods were evident in DsppP19L/+ mice, but only poorly-defined enamel rods were revealed in DsppP19L/P19L mice. Moreover, μCT analyses of the mandibular first molars showed that DsppP19L/+ and DsppP19L/P19L mice had a significant reduction in enamel volume and enamel density at the ages of 2, 3, and 24weeks after birth. Backscattered and acid-etched SEM analyses revealed that while 3-week-old DsppP19L/+ mice had similar pattern of enamel rods in the mandibular first molars as age-matched wild-type mice, no distinct enamel rods were observed in DsppP19L/P19L mice. Yet neither DsppP19L/+ nor DsppP19L/P19L mice showed well-defined enamel rods in the mandibular first molars by the age of 24weeks, as judged by backscattered and acid-etched SEM. In situ hybridization showed that DSPP mRNA level was markedly reduced in the presecretory ameloblasts, but immunohistochemistry revealed that DSP/DSPP immunostaining signals were much stronger within the presecretory ameloblasts in Dspp mutant mice than in wild-type mice. These results suggest that mutant P19L-DSPP protein caused developmental enamel defects in mice, which may be associated with intracellular retention of mutant DSPP in the presecretory ameloblasts.
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Affiliation(s)
- Tian Liang
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University College of Dentistry, Dallas, TX, United States
| | - Qian Xu
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University College of Dentistry, Dallas, TX, United States
| | - Hua Zhang
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University College of Dentistry, Dallas, TX, United States
| | - Suzhen Wang
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University College of Dentistry, Dallas, TX, United States
| | - Thomas G H Diekwisch
- Department of Periodontics and Center for Craniofacial Research and Diagnosis, Texas A&M University College of Dentistry, Dallas, TX, United States
| | - Chunlin Qin
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University College of Dentistry, Dallas, TX, United States
| | - Yongbo Lu
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University College of Dentistry, Dallas, TX, United States
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Yu S, Zhang C, Zhu C, Quan J, Liu D, Wang X, Zheng S. A novel ENAM mutation causes hypoplastic amelogenesis imperfecta. Oral Dis 2021; 28:1610-1619. [PMID: 33864320 DOI: 10.1111/odi.13877] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/14/2021] [Accepted: 03/16/2021] [Indexed: 12/16/2022]
Abstract
OBJECTIVES To identify the genetic cause of one Chinese family with hypoplastic amelogenesis imperfecta (AI) and explore the relationship between genotype and its phenotype. MATERIAL AND METHODS One Chinese family with generalized hypoplastic AI was recruited. One deciduous tooth from the proband was subjected to scanning electron microscopy. Whole-exome sequencing was performed and identified mutation was confirmed by Sanger sequencing. Bioinformatics studies were further conducted to analyze potential deleterious effects of the mutation. RESULTS The proband presented a typical hypoplastic AI phenotype whose teeth in deciduous and permanent dentitions showed thin, yellow, and hard enamel surface. The affected enamel in deciduous tooth showed irregular, broken, and collapsing enamel rods with borders of the enamel prisms undulated and structural shapes of prisms irregular. A novel homozygous nonsense mutation in the last exon of the enamelin (ENAM) gene (NM_031889.3; c.2078C>G) was identified in the proband, which was predicted to produce a highly truncated protein (NP_114095.2; p.(Ser693*)). This mutation was also identified in the proband's parents in heterozygous form. Surprisingly, the clinical phenotype of the heterozygous parents varied from a lack of penetrance to mild enamel defects. Additional bioinformatics studies demonstrated that the detected mutation could change the 3D structure of the ENAM protein and severely damaged the function of ENAM. CONCLUSION The novel homozygous ENAM mutation resulted in hypoplastic AI in the present study. Our results provide new genetic evidence that mutations involved in ENAM contribute to hypoplastic AI.
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Affiliation(s)
- Shunlan Yu
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Chenying Zhang
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Ce Zhu
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Junkang Quan
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Dandan Liu
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Xiaozhe Wang
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Shuguo Zheng
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
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13
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Aryal YP, Lee ES, Kim TY, Sung S, Kim JY, An SY, Jung JK, Ha JH, Suh JY, Yamamoto H, Sohn WJ, Cho SW, Lee Y, An CH, Kim JY. Stage-specific expression patterns of ER stress-related molecules in mice molars: Implications for tooth development. Gene Expr Patterns 2020; 37:119130. [PMID: 32758541 DOI: 10.1016/j.gep.2020.119130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 01/13/2023]
Abstract
The endoplasmic reticulum (ER) is a site where protein folding and posttranslational modifications occur, but when unfolded or misfolded proteins accumulate in the ER lumen, an unfolded protein response (UPR) occurs. A UPR activates ER-stress signalling genes, including inositol-requiring enzyme-1 (Ire1), activating transcription factor 6 (Atf6), and double-stranded RNA-activated protein kinase-like endoplasmic reticulum kinase (Perk), to maintain homeostasis. The involvement of ER stress molecules in metabolic disease and hard tissue matrix formation has been established; however, an understanding of the role of ER-stress signalling molecules in tooth development is lacking. The aims of this study are to define the stage-specific expression patterns of ER stress-related molecules and to elucidate their putative functions in the organogenesis of teeth. This study leverages knowledge of the tissue morphology and expression patterns of a range of signalling molecules during tooth development. RT-qPCR, in situ hybridization, and immunohistochemistry analyses were performed to determine the stage-specific expression patterns of ER-stress-related signalling molecules at important stages of tooth development. RT-qPCR analyses showed that Atf6 and Perk have similar expression levels during all stages of tooth development; however, the expression levels of Ire1 and its downstream target X-box binding protein (Xbp1) increased significantly from the cap to the secretory stage of tooth development. In situ hybridization results revealed that Atf6 and Xbp1 were expressed in cells that form the enamel knot at cap stage and ameloblasts and odontoblasts at secretory stage in stage-specific patterns. In addition, Atf6, Ire1, and Xbp1 expression exhibited distinct localization patterns in secretory odontoblasts and ameloblasts of PN0 molars. Overall, our results strongly suggest that ER-stress molecules are involved in tooth development in response to protein overload that occurs during signaling modulations from enamel knots at cap stage and extracellular matrix secretion at secretory stage.
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Affiliation(s)
- Yam Prasad Aryal
- Department of Biochemistry, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Eui-Seon Lee
- Department of Biochemistry, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Tae-Young Kim
- Department of Biochemistry, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Shijin Sung
- Department of Biochemistry, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Ji-Youn Kim
- Department of Dental Hygiene, Gachon University, Incheon, South Korea
| | - Seo-Young An
- Department of Oral and Maxillofacial Radiology, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Jae-Kwang Jung
- Department of Oral Medicine, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Jung-Hong Ha
- Department of Conservative Dentistry, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Jo-Young Suh
- Department of Periodontology, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Hitoshi Yamamoto
- Department of Histology and Developmental Biology, Tokyo Dental College, Tokyo, Japan
| | - Wern-Joo Sohn
- Pre-Major of Cosmetics and Pharmaceutics, Daegu Haany University, Gyeongsan, South Korea
| | - Sung-Won Cho
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Yonsei University College of Dentistry, Seoul, South Korea
| | - Youngkyun Lee
- Department of Biochemistry, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Chang-Hyeon An
- Department of Oral and Maxillofacial Radiology, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea
| | - Jae-Young Kim
- Department of Biochemistry, School of Dentistry, IHBR, Kyungpook National University, 2177, Dalgubeol-daero, Jung-gu, Daegu, 41940, South Korea.
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14
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Aryal YP, Neupane S, Adhikari N, An C, Ha J, Kwon T, Yamamoto H, Jung J, Park E, Kim J, Cho S, Sohn W, Lee Y, Chae H, Kim H, Kim J. An endoplasmic reticulum stress regulator,
Tmbim6
, modulates secretory stage of mice molar. J Cell Physiol 2019; 234:20354-20365. [DOI: 10.1002/jcp.28635] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/21/2019] [Accepted: 03/25/2019] [Indexed: 01/06/2023]
Affiliation(s)
- Yam Prasad Aryal
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Sanjiv Neupane
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Nirpesh Adhikari
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Chang‐Hyeon An
- Department of Oral and Maxillofacial Radiology, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Jung‐Hong Ha
- Department of Conservative Dentistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Tae‐Yub Kwon
- Department of Dental Biomaterials, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Hitoshi Yamamoto
- Department of Histology and Developmental Biology Tokyo Dental College Tokyo Japan
| | - Jae‐Kwang Jung
- Department of Oral Medicine, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Eui‐Kyun Park
- Department of Oral Pathology and Regenerative Medicine, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Ji‐Youn Kim
- Department of Dental Hygiene Gachon University Incheon Korea
| | - Sung‐Won Cho
- Division in Anatomy and Developmental Biology, Department of Oral Biology Yonsei University College of Dentistry Seoul Korea
| | - Wern‐Joo Sohn
- Pre‐Major of Cosmetics and Pharmaceutics Daegu Haany University Gyeongsan Korea
| | - Youngkyun Lee
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Han‐Jung Chae
- Department of Pharmacology and New Drug Development Institute Chonbuk National University Jeonju Korea
| | - Hyung‐Ryong Kim
- Institute of Tissue Regeneration Engineering (ITREN) Dankook University Cheonan Korea
| | - Jae‐Young Kim
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
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15
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Abstract
X-ray micro CT has become a popular methodology for the nondestructive analysis of dental tissues and has been used extensively in the amelogenesis field. The aim of this chapter is to introduce ImageJ/Fiji to researchers new to CT scanning and the analysis of CT image data. The program can be applied to analyzing X-ray CT images of enamel but can be extrapolated to other tissues as well.
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16
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Eckstein M, Aulestia FJ, Nurbaeva MK, Lacruz RS. Altered Ca 2+ signaling in enamelopathies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1778-1785. [PMID: 29750989 DOI: 10.1016/j.bbamcr.2018.04.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/26/2018] [Accepted: 04/30/2018] [Indexed: 10/16/2022]
Abstract
Biomineralization requires the controlled movement of ions across cell barriers to reach the sites of crystal growth. Mineral precipitation occurs in aqueous phases as fluids become supersaturated with specific ionic compositions. In the biological world, biomineralization is dominated by the presence of calcium (Ca2+) in crystal lattices. Ca2+ channels are intrinsic modulators of this process, facilitating the availability of Ca2+ within cells in a tightly regulated manner in time and space. Unequivocally, the most mineralized tissue produced by vertebrates, past and present, is dental enamel. With some of the longest carbonated hydroxyapatite (Hap) crystals known, dental enamel formation is fully coordinated by specialized epithelial cells of ectodermal origin known as ameloblasts. These cells form enamel in two main developmental stages: a) secretory; and b) maturation. The secretory stage is marked by volumetric growth of the tissue with limited mineralization, and the opposite is found in the maturation stage, as enamel crystals expand in width concomitant with increased ion transport. Disruptions in the formation and/or mineralization stages result, in most cases, in permanent alterations in the crystal assembly. This introduces weaknesses in the material properties affecting enamel's hardness and durability, thus limiting its efficacy as a biting, chewing tool and increasing the possibility of pathology. Here, we briefly review enamel development and discuss key properties of ameloblasts and their Ca2+-handling machinery, and how alterations in this toolkit result in enamelopathies.
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Affiliation(s)
- Miriam Eckstein
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, United States
| | - Francisco J Aulestia
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, United States
| | - Meerim K Nurbaeva
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, United States
| | - Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, United States.
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17
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Brookes SJ, Barron MJ, Dixon MJ, Kirkham J. The Unfolded Protein Response in Amelogenesis and Enamel Pathologies. Front Physiol 2017; 8:653. [PMID: 28951722 PMCID: PMC5599773 DOI: 10.3389/fphys.2017.00653] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
During the secretory phase of their life-cycle, ameloblasts are highly specialized secretory cells whose role is to elaborate an extracellular matrix that ultimately confers both form and function to dental enamel, the most highly mineralized of all mammalian tissues. In common with many other “professional” secretory cells, ameloblasts employ the unfolded protein response (UPR) to help them cope with the large secretory cargo of extracellular matrix proteins transiting their ER (endoplasmic reticulum)/Golgi complex and so minimize ER stress. However, the UPR is a double-edged sword, and, in cases where ER stress is severe and prolonged, the UPR switches from pro-survival to pro-apoptotic mode. The purpose of this review is to consider the role of the ameloblast UPR in the biology and pathology of amelogenesis; specifically in respect of amelogenesis imperfecta (AI) and fluorosis. Some forms of AI appear to correspond to classic proteopathies, where pathological intra-cellular accumulations of protein tip the UPR toward apoptosis. Fluorosis also involves the UPR and, while not of itself a classic proteopathic disease, shares some common elements through the involvement of the UPR. The possibility of therapeutic intervention by pharmacological modulation of the UPR in AI and fluorosis is also discussed.
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Affiliation(s)
- Steven J Brookes
- Division of Oral Biology, School of Dentistry, University of Leeds, St James's University HospitalLeeds, United Kingdom
| | - Martin J Barron
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of ManchesterManchester, United Kingdom
| | - Michael J Dixon
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of ManchesterManchester, United Kingdom
| | - Jennifer Kirkham
- Division of Oral Biology, School of Dentistry, University of Leeds, St James's University HospitalLeeds, United Kingdom
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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: 153] [Impact Index Per Article: 21.9] [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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