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Souza Bomfim GH, Mitaishvili E, Schnetkamp PP, Lacruz RS. Na+/Ca2+ exchange in enamel cells is dominated by the K+-dependent NCKX exchanger. J Gen Physiol 2024; 156:e202313372. [PMID: 37947795 PMCID: PMC10637953 DOI: 10.1085/jgp.202313372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 08/15/2023] [Accepted: 10/31/2023] [Indexed: 11/12/2023] Open
Abstract
Calcium (Ca2+) extrusion is an essential function of the enamel-forming ameloblasts, providing Ca2+ for extracellular mineralization. The plasma membrane Ca2+ ATPases (PMCAs) remove cytosolic Ca2+ (cCa2+) and were recently shown to be efficient when ameloblasts experienced low cCa2+ elevation. Sodium-calcium (Na+/Ca2+) exchange has higher capacity to extrude cCa2+, but there is limited evidence on the function of the two main families of Na+/Ca2+ exchangers in enamel formation. The purpose of this study was to analyze the function of the NCX (coded by SLC8) and the K+-dependent NCKX (coded by SLC24) exchangers in rat ameloblasts and to compare their efficacy in the two main stages of enamel formation: the enamel forming secretory stage and the mineralizing or maturation stage. mRNA expression profiling confirmed the expression of Slc8 and Slc24 genes in enamel cells, Slc24a4 being the most highly upregulated transcript during the maturation stage, when Ca2+ transport increases. Na+/Ca2+ exchange was analyzed in the Ca2+ influx mode in Fura-2 AM-loaded ameloblasts. We show that maturation-stage ameloblasts have a higher Na+/Ca2+ exchange capacity than secretory-stage cells. We also show that Na+/Ca2+ exchange in both stages is dominated by NCKX over NCX. The importance of NCKX function in ameloblasts may partly explain why mutations in the SLC24A4 gene, but not in SLC8 genes, result in enamel disease. Our results demonstrate that Na+/Ca2+ exchangers are fully operational in ameloblasts and that their contribution to Ca2+ homeostasis increases in the maturation stage, when Ca2+ transport need is higher.
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Affiliation(s)
| | - Erna Mitaishvili
- Department of Chemistry, Herbert H. Lehman College, City University of New York. PhD Program in Biology, The Graduate Center of The City University of New York, New York, NY, USA
| | - Paul P.M. Schnetkamp
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Rodrigo S. Lacruz
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
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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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Said R, Mortazavi H, Cooper D, Ovens K, McQuillan I, Papagerakis S, Papagerakis P. Deciphering the functions of Stromal Interaction Molecule-1 in amelogenesis using AmelX-iCre mice. Front Physiol 2023; 14:1100714. [PMID: 36935757 PMCID: PMC10014868 DOI: 10.3389/fphys.2023.1100714] [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: 11/17/2022] [Accepted: 02/17/2023] [Indexed: 03/05/2023] Open
Abstract
Introduction: The intracellular Ca2+ sensor stromal interaction molecule 1 (STIM1) is thought to play a critical role in enamel development, as its mutations cause Amelogenesis Imperfecta (AI). We recently established an ameloblast-specific (AmelX-iCre) Stim1 conditional deletion mouse model to investigate the role of STIM1 in controlling ameloblast function and differentiation in vivo (Stim1 cKO). Our pilot data (Said et al., J. Dent. Res., 2019, 98, 1002-1010) support our hypothesis for a broad role of Stim1 in amelogenesis. This paper aims to provide an in-depth characterization of the enamel phenotype observed in our Stim1 cKO model. Methods: We crossed AmelX-iCre mice with Stim1-floxed animals to develop ameloblast-specific Stim1 cKO mice. Scanning electron microscopy, energy dispersive spectroscopy, and micro- CT were used to study the enamel phenotype. RNAseq and RT-qPCR were utilized to evaluate changes in the gene expression of several key ameloblast genes. Immunohistochemistry was used to detect the amelogenin, matrix metalloprotease 20 and kallikrein 4 proteins in ameloblasts. Results: Stim1 cKO animals exhibited a hypomineralized AI phenotype, with reduced enamel volume, diminished mineral density, and lower calcium content. The mutant enamel phenotype was more severe in older Stim1 cKO mice compared to younger ones and changes in enamel volume and mineral content were more pronounced in incisors compared to molars. Exploratory RNAseq analysis of incisors' ameloblasts suggested that ablation of Stim1 altered the expression levels of several genes encoding enamel matrix proteins which were confirmed by subsequent RT-qPCR. On the other hand, RT-qPCR analysis of molars' ameloblasts showed non-significant differences in the expression levels of enamel matrix genes between control and Stim1-deficient cells. Moreover, gene expression analysis of incisors' and molars' ameloblasts showed that Stim1 ablation caused changes in the expression levels of several genes associated with calcium transport and mitochondrial kinetics. Conclusions: Collectively, these findings suggest that the loss of Stim1 in ameloblasts may impact enamel mineralization and ameloblast gene expression.
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Affiliation(s)
- Raed Said
- College of Dentistry, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Helyasadat Mortazavi
- College of Dentistry, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - David Cooper
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Katie Ovens
- Department of Computer Science, University of Calgary, Calgary, AB, Canada
| | - Ian McQuillan
- Department of Computer Sciences, College of Arts and Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Silvana Papagerakis
- Department of Surgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Petros Papagerakis
- College of Dentistry, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
- *Correspondence: Petros Papagerakis,
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Souza Bomfim GH, Giacomello M, Lacruz RS. PMCA Ca 2+ clearance in dental enamel cells depends on the magnitude of cytosolic Ca 2. FASEB J 2023; 37:e22679. [PMID: 36515675 PMCID: PMC11006021 DOI: 10.1096/fj.202201291r] [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: 08/08/2022] [Revised: 10/31/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022]
Abstract
Enamel formation (amelogenesis) is a two-step process whereby crystals partially grow during the secretory stage followed by a significant growth expansion during the maturation stage concurrent with an increase in vectorial Ca2+ transport. This requires tight regulation of cytosolic Ca2+ (c Ca2+ ) concentration in the enamel forming ameloblasts by controlling Ca2+ influx (entry) and Ca2+ extrusion (clearance). Gene and protein expression studies suggest that the plasma membrane Ca2+ -ATPases (PMCA1-4) are likely involved in c Ca2+ extrusion in ameloblasts, yet no functional analysis of these pumps has been reported nor whether their activity changes across amelogenesis. PMCAs have high Ca2+ affinity and low Ca2+ clearance which may be a limiting factor in their contribution to enamel formation as maturation stage ameloblasts handle high Ca2+ loads. We analyzed PMCA function in rat secretory and maturation ameloblasts by blocking or potentiating these pumps. Low/moderate elevations in c Ca2+ measured using the Ca2+ probe Fura-2-AM show that secretory ameloblasts clear Ca2+ faster than maturation stage cells through PMCAs. This process was completely inhibited by an external alkaline (pH 9.0) solution or was significantly delayed by the PMCA blockers vanadate and caloxin 1b1. Eliciting higher c Ca2+ transients via the activation of the ORAI1 Ca2+ channel showed that the PMCAs of maturation ameloblasts were more efficient. Inhibiting PMCAs decreased the rate of Ca2+ influx via ORAI1 but potentiation with forskolin had no effect. Our findings suggest that PMCAs are functional Ca2+ pumps during amelogenesis regulating c Ca2+ upon low and/or moderate Ca2+ stimulus in secretory stage, thus participating in amelogenesis.
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Affiliation(s)
| | - Marta Giacomello
- Department of Biology, University of Padova, Padua, Italy
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Rodrigo S. Lacruz
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, New York, USA
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Elzein R, Abdel-Sater F, Mehawej C, Jalkh N, Ayoub F, Chouery E. Identification by whole-exome sequencing of new single-nucleotide polymorphisms associated with molar-incisor hypomineralisation among the Lebanese population. Eur Arch Paediatr Dent 2022; 23:919-928. [PMID: 35986881 DOI: 10.1007/s40368-022-00738-2] [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: 02/20/2022] [Accepted: 07/21/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Molar-incisor hypomineralization (MIH) is a developmental qualitative enamel defect, causing a worldwide challenging dental problem. The etiology of this defect remains unclear. Here we identify by whole-exome sequencing (WES) new single-nucleotide polymorphisms (SNPs) in genes expressed during enamel mineralization and in those modulating prenatal, natal and postnatal risk factors among the Lebanese MIH children: immune system and xenobiotic detoxification. DESIGN Dental examination for MIH was performed based on the MIH index for diagnostic criteria. Saliva samples were collected from 37 non-related, MIH-diagnosed subjects for DNA extraction. WES was performed on the Illumina HiSeq2000 platform. The χ2 test and Fisher's exact test were used to determine relationship between SNPs frequencies and MIH. OR and its 95% CI were used to report the strength of association. The significance threshold was set at 0.05. RESULTS Among the Lebanese population, 37 SNPs presented a significant association with MIH in the following genes: AMTN, MMP-20, STIM1, STIM2, ORAI1, SLC34A2, SLC34A3, VDR, PVALB, HSP90B1, TRPM7, SLC24A4, CA6, SLC4A2, TNFRSF11A, IL10RB, ARNT, ESR1 and CYP1B1. CONCLUSION This is the first WES study conducted in patients with MIH. Yet, interactions between polymorphisms in different gene categories are to be investigated for a better assessment of MIH susceptibility.
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Affiliation(s)
- R Elzein
- Department of Pediatric Dentistry and Public Dental Health, Faculty of Dental Medicine, Lebanese University, Beirut, Lebanon. .,Medical Genetics Unit, Faculty of Medicine, Saint-Joseph University, Beirut, Lebanon.
| | - F Abdel-Sater
- Laboratory of Cancer Biology and Cellular Immunology, Department of Biological Sciences, Faculty of Sciences, Lebanese University, Beirut, Lebanon
| | - C Mehawej
- Department of Human Genetics, Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, Lebanon
| | - N Jalkh
- Medical Genetics Unit, Faculty of Medicine, Saint-Joseph University, Beirut, Lebanon
| | - F Ayoub
- Department of Forensic Odontology, Human Identification and Anthropology, Faculty of Dental Medicine, Lebanese University, Beirut, Lebanon
| | - E Chouery
- Department of Human Genetics, Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, Lebanon
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Arai H, Inaba A, Ikezaki S, Kumakami-Sakano M, Azumane M, Ohshima H, Morikawa K, Harada H, Otsu K. Energy metabolic shift contributes to the phenotype modulation of maturation stage ameloblasts. Front Physiol 2022; 13:1062042. [PMID: 36523561 PMCID: PMC9745043 DOI: 10.3389/fphys.2022.1062042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 11/15/2022] [Indexed: 12/13/2023] Open
Abstract
Maturation stage ameloblasts (M-ABs) are responsible for terminal enamel mineralization in teeth and undergo characteristic cyclic changes in both morphology and function between ruffle-ended ameloblasts (RA) and smooth-ended ameloblasts (SA). Energy metabolism has recently emerged as a potential regulator of cell differentiation and fate decisions; however, its implication in M-ABs remains unclear. To elucidate the relationship between M-ABs and energy metabolism, we examined the expression pattern of energy metabolic enzymes in M-ABs of mouse incisors. Further, using the HAT7 cell line with M-AB characteristics, we designed experiments to induce an energy metabolic shift by changes in oxygen concentration. We revealed that RA preferentially utilizes oxidative phosphorylation, whereas SA depends on glycolysis-dominant energy metabolism in mouse incisors. In HAT7 cells, hypoxia induced an energy metabolic shift toward a more glycolytic-dominant state, and the energy metabolic shift reduced alkaline phosphatase (ALP) activity and calcium transport and deposition with a change in calcium-related gene expression, implying a phenotype shift from RA to SA. Taken together, these results indicate that the energy metabolic state is an important determinant of the RA/SA phenotype in M-ABs. This study sheds light on the biological significance of energy metabolism in governing M-ABs, providing a novel molecular basis for understanding enamel mineralization and elucidating the pathogenesis of enamel hypomineralization.
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Affiliation(s)
- Haruno Arai
- Division of Developmental Biology and Regenerative Medicine, Department of Anatomy, Iwate Medical University, Yahaba, Japan
- Division of Pediatric and Special Care Dentistry, Department of Oral Health Science, School of Dentistry, Iwate Medical University, Morioka, Japan
| | - Akira Inaba
- Division of Developmental Biology and Regenerative Medicine, Department of Anatomy, Iwate Medical University, Yahaba, Japan
- Division of Pediatric and Special Care Dentistry, Department of Oral Health Science, School of Dentistry, Iwate Medical University, Morioka, Japan
| | - Shojiro Ikezaki
- Division of Developmental Biology and Regenerative Medicine, Department of Anatomy, Iwate Medical University, Yahaba, Japan
| | - Mika Kumakami-Sakano
- Division of Developmental Biology and Regenerative Medicine, Department of Anatomy, Iwate Medical University, Yahaba, Japan
| | - Marii Azumane
- Division of Developmental Biology and Regenerative Medicine, Department of Anatomy, Iwate Medical University, Yahaba, Japan
- Division of Oral and Maxillofacial Surgery, Department of Reconstructive Oral and Maxillofacial Surgery, Iwate Medical University, Morioka, Japan
| | - Hayato Ohshima
- Division of Anatomy and Cell Biology of the Hard Tissue, Department of Tissue Regeneration and Reconstruction, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Kazumasa Morikawa
- Division of Pediatric and Special Care Dentistry, Department of Oral Health Science, School of Dentistry, Iwate Medical University, Morioka, Japan
| | - Hidemitsu Harada
- Division of Developmental Biology and Regenerative Medicine, Department of Anatomy, Iwate Medical University, Yahaba, Japan
| | - Keishi Otsu
- Division of Developmental Biology and Regenerative Medicine, Department of Anatomy, Iwate Medical University, Yahaba, Japan
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Li Y, Costiniti V, Souza Bomfim GH, Neginskaya M, Son GY, Rothermel B, Pavlov E, Lacruz RS. Overexpression of RCAN1, a Gene on Human Chromosome 21, Alters Cell Redox and Mitochondrial Function in Enamel Cells. Cells 2022; 11:3576. [PMID: 36429004 PMCID: PMC9688881 DOI: 10.3390/cells11223576] [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: 10/04/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
Abstract
The regulator of calcineurin (RCAN1) has been implicated in the pathogenesis of Down syndrome (DS). Individuals with DS show dental abnormalities for unknown reasons, and RCAN1 levels have been found to be elevated in several tissues of DS patients. A previous microarray analysis comparing cells of the two main formative stages of dental enamel, secretory and maturation, showed a significant increase in RCAN1 expression in the latter. Because the function of RCAN1 during enamel formation is unknown, there is no mechanistic evidence linking RCAN1 with the dental anomalies in individuals with DS. We investigated the role of RCAN1 in enamel by overexpressing RCAN1 in the ameloblast cell line LS8 (LS8+RCAN1). We first confirmed that RCAN1 is highly expressed in maturation stage ameloblasts by qRT-PCR and used immunofluorescence to show its localization in enamel-forming ameloblasts. We then analyzed cell redox and mitochondrial bioenergetics in LS8+RCAN1 cells because RCAN1 is known to impact these processes. We show that LS8+RCAN1 cells have increased reactive oxygen species (ROS) and decreased mitochondrial bioenergetics without changes in the expression of the complexes of the electron transport chain, or in NADH levels. However, LS8+RCAN1 cells showed elevated mitochondrial Ca2+ uptake and decreased expression of several enamel genes essential for enamel formation. These results provide insight into the role of RCAN1 in enamel and suggest that increased RCAN1 levels in the ameloblasts of individuals with DS may impact enamel formation by altering both the redox environment and mitochondrial function, as well as decreasing the expression of enamel-specific genes.
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Affiliation(s)
- Yi Li
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
| | - Veronica Costiniti
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
| | - Guilherme H. Souza Bomfim
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
| | - Maria Neginskaya
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
| | - Ga-Yeon Son
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
| | - Beverly Rothermel
- Department of Internal Medicine and Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Evgeny Pavlov
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
| | - Rodrigo S. Lacruz
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
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Choi H, Lee K, Kim D, Kim S, Lee JH. The implication of holocytochrome c synthase mutation in Korean familial hypoplastic amelogenesis imperfecta. Clin Oral Investig 2022; 26:4487-4498. [PMID: 35243551 PMCID: PMC9203382 DOI: 10.1007/s00784-022-04413-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/15/2022] [Indexed: 11/18/2022]
Abstract
Objectives This study aimed to comprehensively characterise genetic variants of amelogenesis imperfecta in a single Korean family through whole-exome sequencing and bioinformatics analysis. Material and methods Thirty-one individuals of a Korean family, 9 of whom were affected and 22 unaffected by amelogenesis imperfecta, were enrolled. Whole-exome sequencing was performed on 12 saliva samples, including samples from 8 affected and 4 unaffected individuals. The possible candidate genes associated with the disease were screened by segregation analysis and variant filtering. In silico mutation impact analysis was then performed on the filtered variants based on sequence conservation and protein structure. Results Whole-exome sequencing data revealed an X-linked dominant, heterozygous genomic missense mutation in the mitochondrial gene holocytochrome c synthase (HCCS). We also found that HCCS is potentially related to the role of mitochondria in amelogenesis. The HCCS variant was expected to be deleterious in both evolution-based and large population-based analyses. Further, the variant was predicted to have a negative effect on catalytic function of HCCS by in silico analysis of protein structure. In addition, HCCS had significant association with amelogenesis in literature mining analysis. Conclusions These findings suggest new evidence for the relationship between amelogenesis and mitochondria function, which could be implicated in the pathogenesis of amelogenesis imperfecta. Clinical relevance The discovery of HCCS mutations and a deeper understanding of the pathogenesis of amelogenesis imperfecta could lead to finding solutions for the fundamental treatment of this disease. Furthermore, it enables dental practitioners to establish predictable prosthetic treatment plans at an early stage by early detection of amelogenesis imperfecta through personalised medicine. Supplementary Information The online version contains supplementary material available at 10.1007/s00784-022-04413-0.
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Affiliation(s)
- Hyejin Choi
- Department of Prosthodontics, College of Dentistry at Yonsei University, 50-1 Yonsei-ro, Seodaemoon-gu, Seoul, 120-752, Republic of Korea
| | - Kwanghwan Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
| | - Donghyo Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
| | - Sanguk Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea.
| | - Jae Hoon Lee
- Department of Prosthodontics, College of Dentistry at Yonsei University, 50-1 Yonsei-ro, Seodaemoon-gu, Seoul, 120-752, Republic of Korea.
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Organoids from human tooth showing epithelial stemness phenotype and differentiation potential. Cell Mol Life Sci 2022; 79:153. [PMID: 35217915 PMCID: PMC8881251 DOI: 10.1007/s00018-022-04183-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/27/2022] [Accepted: 02/01/2022] [Indexed: 01/09/2023]
Abstract
Insight into human tooth epithelial stem cells and their biology is sparse. Tissue-derived organoid models typically replicate the tissue’s epithelial stem cell compartment. Here, we developed a first-in-time epithelial organoid model starting from human tooth. Dental follicle (DF) tissue, isolated from unerupted wisdom teeth, efficiently generated epithelial organoids that were long-term expandable. The organoids displayed a tooth epithelial stemness phenotype similar to the DF’s epithelial cell rests of Malassez (ERM), a compartment containing dental epithelial stem cells. Single-cell transcriptomics reinforced this organoid-ERM congruence, and uncovered novel, mouse-mirroring stem cell features. Exposure of the organoids to epidermal growth factor induced transient proliferation and eventual epithelial-mesenchymal transition, highly mimicking events taking place in the ERM in vivo. Moreover, the ERM stemness organoids were able to unfold an ameloblast differentiation process, further enhanced by transforming growth factor-β (TGFβ) and abrogated by TGFβ receptor inhibition, thereby reproducing TGFβ's known key position in amelogenesis. Interestingly, by creating a mesenchymal-epithelial composite organoid (assembloid) model, we demonstrated that the presence of dental mesenchymal cells (i.e. pulp stem cells) triggered ameloblast differentiation in the epithelial stem cells, thus replicating the known importance of mesenchyme-epithelium interaction in tooth development and amelogenesis. Also here, differentiation was abrogated by TGFβ receptor inhibition. Together, we developed novel organoid models empowering the exploration of human tooth epithelial stem cell biology and function as well as their interplay with dental mesenchyme, all at present only poorly defined in humans. Moreover, the new models may pave the way to future tooth-regenerative perspectives.
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Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous Ca2+ signaling pathway that is evolutionarily conserved across eukaryotes. SOCE is triggered physiologically when the endoplasmic reticulum (ER) Ca2+ stores are emptied through activation of inositol 1,4,5-trisphosphate receptors. SOCE is mediated by the Ca2+ release-activated Ca2+ (CRAC) channels, which are highly Ca2+ selective. Upon store depletion, the ER Ca2+-sensing STIM proteins aggregate and gain extended conformations spanning the ER-plasma membrane junctional space to bind and activate Orai, the pore-forming proteins of hexameric CRAC channels. In recent years, studies on STIM and Orai tissue-specific knockout mice and gain- and loss-of-function mutations in humans have shed light on the physiological functions of SOCE in various tissues. Here, we describe recent findings on the composition of native CRAC channels and their physiological functions in immune, muscle, secretory, and neuronal systems to draw lessons from transgenic mice and human diseases caused by altered CRAC channel activity.
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Affiliation(s)
- Scott M Emrich
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA;
| | - Ryan E Yoast
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA;
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA;
- Department of Pharmacology and Chemical Biology and Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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11
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Costiniti V, Bomfim GHS, Neginskaya M, Son GY, Mitaishvili E, Giacomello M, Pavlov E, Lacruz RS. Mitochondria modulate ameloblast Ca 2+ signaling. FASEB J 2022; 36:e22169. [PMID: 35084775 PMCID: PMC8852362 DOI: 10.1096/fj.202100602r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 12/22/2021] [Accepted: 01/07/2022] [Indexed: 02/03/2023]
Abstract
The role of mitochondria in enamel, the most mineralized tissue in the body, is poorly defined. Enamel is formed by ameloblast cells in two main sequential stages known as secretory and maturation. Defining the physiological features of each stage is essential to understand mineralization. Here, we analyzed functional features of mitochondria in rat primary secretory and maturation-stage ameloblasts focusing on their role in Ca2+ signaling. Quantification of the Ca2+ stored in the mitochondria by trifluoromethoxy carbonylcyanide phenylhydrazone stimulation was comparable in both stages. The release of endoplasmic reticulum Ca2+ pools by adenosine triphosphate in rhod2AM-loaded cells showed similar mitochondrial Ca2+ (m Ca2+ ) uptake. However, m Ca2+ extrusion via Na+ -Li+ -Ca2+ exchanger was more prominent in maturation. To address if m Ca2+ uptake via the mitochondrial Ca2+ uniporter (MCU) played a role in cytosolic Ca2+ (c Ca2+ ) buffering, we stimulated Ca2+ influx via the store-operated Ca2+ entry (SOCE) and blocked MCU with the inhibitor Ru265. This inhibitor was first tested using the enamel cell line LS8 cells. Ru265 prevented c Ca2+ clearance in permeabilized LS8 cells like ruthenium red, and it did not affect ΔΨm in intact cells. In primary ameloblasts, SOCE stimulation elicited a significantly higher m Ca2+ uptake in maturation ameloblasts. The uptake of Ca2+ into the mitochondria was dramatically decreased in the presence of Ru265. Combined, these results suggest an increased mitochondrial Ca2+ handling in maturation but only upon stimulation of Ca2+ influx via SOCE. These functional studies provide insights not only on the role of mitochondria in ameloblast Ca2+ physiology, but also advance the concept that SOCE and m Ca2+ uptake are complementary processes in biological mineralization.
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Affiliation(s)
- Veronica Costiniti
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, USA
| | - Guilherme H. S. Bomfim
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, USA
| | - Maria Neginskaya
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, USA
| | - Ga-Yeon Son
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, USA
| | - Erna Mitaishvili
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, USA
| | - Marta Giacomello
- Department of Biology, University of Padova, Padua, Italy,Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Evgeny Pavlov
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, USA
| | - Rodrigo S. Lacruz
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, USA
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12
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Sp6/Epiprofin is a master regulator in the developing tooth. Biochem Biophys Res Commun 2021; 581:89-95. [PMID: 34662808 PMCID: PMC8585705 DOI: 10.1016/j.bbrc.2021.10.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/25/2021] [Accepted: 10/07/2021] [Indexed: 12/26/2022]
Abstract
Tooth development involves the coordinated transcriptional regulation of extracellular matrix proteins produced by ameloblasts and odontoblasts. In this study, whole-genome ChIP-seq analysis was applied to identify the transcriptional regulatory gene targets of Sp6 in mesenchymal cells of the developing tooth. Bioinformatic analysis of a pool of Sp6 target peaks identified the consensus nine nucleotide binding DNA motif CTg/aTAATTA. Consistent with these findings, a number of enamel and dentin matrix genes including amelogenin (Amelx), ameloblastin (Ambn), enamelin (Enam) and dental sialophosphoprotein (Dspp), were identified to contain Sp6 target sequences. Sp6 peaks were also found in other important tooth genes including transcription factors (Dlx2, Dlx3, Dlx4, Dlx5, Sp6, Sp7, Pitx2, and Msx2) and extracellular matrix-related proteins (Col1a2, Col11a2, Halpn1). Unsupervised UMAP clustering of tooth single cell RNA-seq data confirmed the presence of Sp6 transcripts co-expressed with many of the identified target genes within ameloblasts and odontoblasts. Lastly, transcriptional reporter assays using promoter fragments from the Hapln1 and Sp6 gene itself revealed that Sp6 co-expression enhanced gene transcriptional activity. Taken together these results highlight that Sp6 is a major regulator of multiple extracellular matrix genes in the developing tooth.
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13
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Tanaka D, Ikeda Y, Ikeda E, Yokose M, Ganss B, Iwata T. Effect of Amelotin on Bone Growth in the Murine Calvarial Defect Model. Ann Biomed Eng 2021; 49:3676-3684. [PMID: 34608582 DOI: 10.1007/s10439-021-02867-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/23/2021] [Indexed: 11/26/2022]
Abstract
Amelotin (AMTN) is a protein that is expressed during the maturation of dental enamel and has important role in enamel hydroxyapatite mineralization. However, it is not well understood whether AMTN has a strong mineral-promoting ability in bone. In this study, the effect of AMTN on bone healing was investigated using mice calvarial defect model in vivo, and the expression of bone marker genes and cell proliferation were investigated to clarify the role of AMTN in bone mineralization using mouse osteogenic cells (MC3T3-E1) in vitro. Collagen membranes, with or without recombinant human (rh) AMTN, were applied to calvarial defects created on the parietal bones of C57BL/6N mice. Microcomputed tomography and histological observation revealed that the defect largely filled with mineralized tissue by the rhAMTN-containing membrane in eight weeks. Moreover, CD31 positive cells were observed in the newly formed mineralized tissue and around the rhAMTN-containing membrane. In the presence of rhAMTN, the expression of the Spp1 gene in MC3T3-E1 cells significantly increased within ten days in an osteoinductive medium. Moreover, rhAMTN significantly enhanced MC3T3-E1 cell proliferation. These findings indicate that AMTN positively influences bone repair by promoting hydroxyapatite mineralization.
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Affiliation(s)
- Daiki Tanaka
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8549, Japan
| | - Yuichi Ikeda
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8549, Japan.
| | - Eri Ikeda
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8549, Japan
- Department of Molecular Immunology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mako Yokose
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8549, Japan
| | - Bernhard Ganss
- Faculty of Dentistry and Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Takanori Iwata
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8549, Japan
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14
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Costiniti V, Bomfim GH, Mitaishvili E, Son GY, Li Y, Lacruz RS. Calcium Transport in Specialized Dental Epithelia and Its Modulation by Fluoride. Front Endocrinol (Lausanne) 2021; 12:730913. [PMID: 34456880 PMCID: PMC8385142 DOI: 10.3389/fendo.2021.730913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 07/26/2021] [Indexed: 11/25/2022] Open
Abstract
Most cells use calcium (Ca2+) as a second messenger to convey signals that affect a multitude of biological processes. The ability of Ca2+ to bind to proteins to alter their charge and conformation is essential to achieve its signaling role. Cytosolic Ca2+ (cCa2+) concentration is maintained low at ~100 nM so that the impact of elevations in cCa2+ is readily sensed and transduced by cells. However, such elevations in cCa2+ must be transient to prevent detrimental effects. Cells have developed a variety of systems to rapidly clear the excess of cCa2+ including Ca2+ pumps, exchangers and sequestering Ca2+ within intracellular organelles. This Ca2+ signaling toolkit is evolutionarily adapted so that each cell, tissue, and organ can fulfill its biological function optimally. One of the most specialized cells in mammals are the enamel forming cells, the ameloblasts, which also handle large quantities of Ca2+. The end goal of ameloblasts is to synthesize, secrete and mineralize a unique proteinaceous matrix without the benefit of remodeling or repair mechanisms. Ca2+ uptake into ameloblasts is mainly regulated by the store operated Ca2+ entry (SOCE) before it is transported across the polarized ameloblasts to reach the insulated enamel space. Here we review the ameloblasts Ca2+ signaling toolkit and address how the common electronegative non-metal fluoride can alter its function, potentially addressing the biology of dental fluorosis.
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Affiliation(s)
| | | | | | | | | | - Rodrigo S. Lacruz
- Department Molecular Pathobiology, College of Dentistry, New York University, New York, NY, United States
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15
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Genetic Aspects of Dental Erosive Wear and Dental Caries. Int J Dent 2021; 2021:5566733. [PMID: 34335772 PMCID: PMC8292068 DOI: 10.1155/2021/5566733] [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: 01/15/2021] [Accepted: 07/01/2021] [Indexed: 11/17/2022] Open
Abstract
Objectives The present review aims to give an overview of the literature focusing on novel genetic aspects of dental erosion and dental caries. Once the tooth erupts into the oral cavity, the regenerative capability of enamel is fundamentally limited due to the loss of dental epithelium during eruption. The susceptibility or resistance to dental erosion and caries is presumably a result of environmental, phenotypic, and/or genetic influence. Even though it is evident that individuals frequently exposing their teeth to acid and sugar are at high risk of developing dental erosion and caries, the findings exclusively based on these factors are elusive. Data resources and study selection. The present review was based on data collected from the National Library of Medicine database with different combinations of the following terms: "tooth," "dental," "dentin," "enamel," "erosion," "erosive wear," "caries," "decay," "gene," and "genetic." A total of forty-six studies met the inclusion criteria. Data were extracted by one reviewer and verified by another. Conclusion The high prevalence of erosion and caries among certain groups, and observations that not all individuals appearing to be at risk develop these lesions, has sparked research on identifying genetic effects to these conditions. A connection of genome-wide and candidate gene studies has increased considerably in the literature. This review reveals largely varying success among studies, demonstrating the difficulties of developing the study with adequate sample sizes and durable phenotype definitions that permit enough statistical power to identify genetic contributors.
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16
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Abstract
Mollusc shells are a result of the deposition of crystalline and amorphous calcite catalysed by enzymes and shell matrix proteins. Developing a detailed understanding of bivalve mollusc biomineralization pathways is complicated not only by the multiplicity of shell forms and microstructures in this class, but also by the evolution of associated proteins by domain co-option and domain shuffling. In spite of this, a minimal biomineralization toolbox comprising proteins and protein domains critical for shell production across species has been identified. Using a matched pair design to reduce experimental noise from inter-individual variation, combined with damage-repair experiments and a database of biomineralization shell matrix proteins (SMP) derived from published works, proteins were identified that are likely to be involved in shell calcification. Eighteen new, shared proteins likely to be involved in the processes related to the calcification of shells were identified by analysis of genes expressed during repair in Crassostrea gigas, Mytilus edulis and Pecten maximus. Genes involved in ion transport were also identified as potentially involved in calcification either via the maintenance of cell acid-base balance or transport of critical ions to the extrapallial space, the site of shell assembly. These data expand the number of candidate biomineralization proteins in bivalve molluscs for future functional studies and define a minimal functional protein domain set required to produce solid microstructures from soluble calcium carbonate. This is important for understanding molluscan shell evolution, the likely impacts of environmental change on biomineralization processes, materials science, and biomimicry research.
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Affiliation(s)
- Tejaswi Yarra
- University of Edinburgh, Institute of Evolutionary Biology, Ashworth Laboratories, Charlotte Auerbach Road, Edinburgh, EH9 3FL, UK.,British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
| | - Mark Blaxter
- Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Melody S Clark
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
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17
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Fresia R, Marangoni P, Burstyn-Cohen T, Sharir A. From Bite to Byte: Dental Structures Resolved at a Single-Cell Resolution. J Dent Res 2021; 100:897-905. [PMID: 33764175 PMCID: PMC8293759 DOI: 10.1177/00220345211001848] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The systematic classification of the cells that compose a tissue or an organ is key to understanding how these cells cooperate and interact as a functional unit. Our capacity to detect features that define cell identity has evolved from morphological and chemical analyses, through the use of predefined genetic markers, to unbiased transcriptomic and epigenetic profiling. The innovative technology of single-cell RNA sequencing (scRNA-seq) enables transcriptional profiling of thousands of individual cells. Since its development, scRNA-seq has been extensively applied to numerous organs and tissues in a wide range of animal models and human samples, thereby providing a plethora of fundamental biological insights into their development, homeostasis, and pathology. In this review, we present the findings of 3 recent studies that employed scRNA-seq to unravel the complexity of cellular composition in mammalian teeth. These findings offer an unprecedented catalogue of cell types in the mouse incisor, which is a convenient model system for studying continuous tooth growth. These studies identified novel cell types in the tooth epithelium and mesenchyme, as well as new markers for known cell types. Computational analyses of the data also uncovered the lineage and dynamics of cell states during ameloblast and odontoblast differentiation during both normal homeostasis and injury repair. The transcriptional differences between the mouse incisor and mouse and human molars uncover species-specific as well as shared features in tooth cell composition. Here, we highlight these findings and discuss important similarities and differences between these studies. We also discuss potential future applications of scRNA-seq in dental research and dentistry. Together, these studies demonstrate how the rapidly evolving technology of scRNA-seq can advance the study of tooth development and function and provide putative targets for regenerative approaches.
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Affiliation(s)
- R Fresia
- The Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University, Jerusalem, Israel
| | - P Marangoni
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA
| | - T Burstyn-Cohen
- The Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University, Jerusalem, Israel
| | - A Sharir
- The Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University, Jerusalem, Israel
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18
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Chen Y, Koshy R, Guirado E, George A. STIM1 a calcium sensor promotes the assembly of an ECM that contains Extracellular vesicles and factors that modulate mineralization. Acta Biomater 2021; 120:224-239. [PMID: 33130308 DOI: 10.1016/j.actbio.2020.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 10/04/2020] [Accepted: 10/07/2020] [Indexed: 01/07/2023]
Abstract
Osteoblasts and odontoblasts, are non-excitable cells and facilitate mass calcium transport during matrix mineralization. A sophisticated Ca2+ sensing mechanism is used to maintain Ca2+ homeostasis. STIM1 (Stromal interaction molecule 1) is a calcium sensor protein localized in the ER membrane and maintains calcium homeostasis by initiating the store-operated Ca2+ entry (SOCE) process, following store depletion. The role of STIM1 in dentin mineralization is yet to be elucidated. Therefore, transgenic DPSCs were generated in which overexpression or knockdown of STIM1 was achieved to study its function in matrix mineralization. Gene expression analysis and Alizarin Red staining assay demonstrated upregulation of genes involved in odontogenic differentiation and matrix mineralization with increased calcium deposition with STIM1 overexpression. Topology of the ECM examined by Field Emission Scanning Electron Microscopy (FESEM) showed the presence of large amounts of extracellular microvesicles with mineral deposits. Interestingly, silencing STIM1 resulted in fewer vesicles and less mineral deposits in the ECM. Analysis of the dentin-pulp complex of STIM1- deficient mice by micro-CT show reduced dentin thickness, malformed and highly porous alveolar bone, suggesting a cell intrinsic role for STIM1 in dentin mineralization. Confocal microscopy showed that DMP1-mediated depletion of store Ca2+ resulted in aggregation or "puncta-formation" of STIM1 at the plasma membrane indicative of a gating arrangement with Orai1 for Ca2+ influx. Together, our data provide evidence for an important role for STIM1 in dentin and alveolar bone mineralization by influencing intracellular Ca2+ oscillations that could provide signals for a wide array of cellular functions. STATEMENT OF SIGNIFICANCE: Calcium signaling and transport are fundamental to bone and dentin mineralization. Osteoblasts and odontoblasts transport large amounts of Ca2+ to the extracellular matrix. These cells maintain calcium homeostasis by spatially distributed calcium pumps and channels at the plasma membrane. STIM1 an ER Ca2+ sensor protein is an important component of the store-operated calcium entry (SOCE) process. In this study, we examined the role of STIM1 during the differentiation of dental pulp stem cells into functional odontoblasts and formation of mineralized dentin matrix. Stimulation of these cells with DMP1, a key regulatory protein in matrix mineralization, stimulates STIM1-mediated release of ER Ca2+ and SOCE activation. Silencing of STIM1 impairs signaling events, release of exosomes containing matrix proteins and matrix mineralization.
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Affiliation(s)
- Yinghua Chen
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Rahul Koshy
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Elizabeth Guirado
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Anne George
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL 60612, USA.
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19
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Randazzo AC, Burnheimer JM, Bayram M, Seymen F, Vieira AR. Genetic polymorphisms influence shear bond resistance of orthodontic brackets. J World Fed Orthod 2020; 9:101-105. [PMID: 32943154 DOI: 10.1016/j.ejwf.2020.06.001] [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: 04/02/2020] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 11/24/2022]
Abstract
OBJECTIVES The purpose of this study was to determine if shear bond resistance of orthodontic brackets bonded to enamel is associated with genes implicated in the enamel mineralization process. METHODS Ninety-two permanent, caries-free premolars extracted for orthodontic purposes and their associated saliva samples were obtained. Eighteen single nucleotide polymorphisms (SNPs) were studied for association with shear bond resistance. The genes of interest in this study were those previously associated with dental caries by our group. All tooth samples were bonded on the buccal surface with metallic lower lateral brackets, and then subjected to physical debonding. The force required to debond the bracket was recorded in Newtons (N) and converted to a shear bond resistance value in Megapascals (N/mm2). The data were analyzed for statistical significance as compared with the mean shear bond resistance value via PLINK whole genome analysis software. RESULTS Associations were found between the SNPs for tuftelin (rs7526319, P = 0.004) and amelogenin (rs17878486, P = 0.04) and a higher shear bond resistance. CONCLUSION The collected data support the proposed hypothesis that genes involved in the mineralization process affect the bonding of orthodontic brackets, and such an association is of value for the field of orthodontics, particularly in evaluating the efficacy of enamel-resin bond strength for patients receiving treatment.
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Affiliation(s)
- Adam C Randazzo
- Student, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - John M Burnheimer
- Assistant Professor, Department of Orthodontics, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Merve Bayram
- Assistant Professor, Department of Pedodontics, School of Dentistry, Istanbul Medipol University, Istanbul, Turkey
| | - Figen Seymen
- Professor, Department of Pedodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey
| | - Alexandre R Vieira
- Professor, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
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20
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Said R, Lobanova L, Papagerakis S, Papagerakis P. Calcium Sets the Clock in Ameloblasts. Front Physiol 2020; 11:920. [PMID: 32848861 PMCID: PMC7411184 DOI: 10.3389/fphys.2020.00920] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/09/2020] [Indexed: 01/22/2023] Open
Abstract
Background Stromal interaction molecule 1 (STIM1) is one of the main components of the store operated Ca2+ entry (SOCE) signaling pathway. Individuals with mutated STIM1 present severely hypomineralized enamel characterized as amelogenesis imperfecta (AI) but the downstream molecular mechanisms involved remain unclear. Circadian clock signaling plays a key role in regulating the enamel thickness and mineralization, but the effects of STIM1-mediated AI on circadian clock are unknown. Objectives The aim of this study is to examine the potential links between SOCE and the circadian clock during amelogenesis. Methods We have generated mice with ameloblast-specific deletion of Stim1 (Stim1fl/fl/Amelx-iCre+/+, Stim1 cKO) and analyzed circadian gene expression profile in Stim1 cKO compared to control (Stim1fl/fl/Amelx-iCre–/–) using ameloblast micro-dissection and RNA micro-array of 84 circadian genes. Expression level changes were validated by qRT-PCR and immunohistochemistry. Results Stim1 deletion has resulted in significant upregulation of the core circadian activator gene Brain and Muscle Aryl Hydrocarbon Receptor Nuclear Translocation 1 (Bmal1) and downregulation of the circadian inhibitor Period 2 (Per2). Our analyses also revealed that SOCE disruption results in dysregulation of two additional circadian regulators; p38α mitogen-activated protein kinase (MAPK14) and transforming growth factor-beta1 (TGF-β1). Both MAPK14 and TGF-β1 pathways are known to play major roles in enamel secretion and their dysregulation has been previously implicated in the development of AI phenotype. Conclusion These data indicate that disruption of SOCE significantly affects the ameloblasts molecular circadian clock, suggesting that alteration of the circadian clock may be partly involved in the development of STIM1-mediated AI.
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Affiliation(s)
- Raed Said
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.,College of Dentistry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Liubov Lobanova
- College of Dentistry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Silvana Papagerakis
- Department of Surgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Petros Papagerakis
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.,College of Dentistry, University of Saskatchewan, Saskatoon, SK, Canada
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21
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Costiniti V, Bomfim GH, Li Y, Mitaishvili E, Ye ZW, Zhang J, Townsend DM, Giacomello M, Lacruz RS. Mitochondrial Function in Enamel Development. Front Physiol 2020; 11:538. [PMID: 32547417 PMCID: PMC7274036 DOI: 10.3389/fphys.2020.00538] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/30/2020] [Indexed: 12/11/2022] Open
Abstract
Enamel is the most calcified tissue in vertebrates. Enamel formation and mineralization is a two-step process that is mediated by ameloblast cells during their secretory and maturation stages. In these two stages, ameloblasts are characterized by different morphology and function, which is fundamental for proper mineral growth in the extracellular space. Ultrastructural studies have shown that the mitochondria in these cells localize to different subcellular regions in both stages. However, limited knowledge is available on the role/s of mitochondria in enamel formation. To address this issue, we analyzed mitochondrial biogenesis and respiration, as well as the redox status of rat primary enamel cells isolated from the secretory and maturation stages. We show that maturation stage cells have an increased expression of PGC1α, a marker of mitochondrial biogenesis, and of components of the electron transport chain. Oxygen consumption rate (OCR), a proxy for mitochondrial function, showed a significant increase in oxidative phosphorylation during the maturation stage, promoting ATP production. The GSH/GSSG ratio was lower in the maturation stage, indicative of increased oxidation. Because higher oxidative phosphorylation can lead to higher ROS production, we tested if ROS affected the expression of AmelX and Enam genes that are essential for enamel formation. The ameloblast cell line LS8 treated with H2O2 to promote ROS elicited significant expression changes in AmelX and Enam. Our data highlight important metabolic and physiological differences across the two enamel stages, with higher ATP levels in the maturation stage indicative of a higher energy demand. Besides these metabolic shifts, it is likely that the enhanced ETC function results in ROS-mediated transcriptional changes.
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Affiliation(s)
- Veronica Costiniti
- College of Dentistry, Department of Molecular Pathobiology, New York University, New York, NY, United States
| | - Guilherme H Bomfim
- College of Dentistry, Department of Molecular Pathobiology, New York University, New York, NY, United States
| | - Yi Li
- College of Dentistry, Department of Molecular Pathobiology, New York University, New York, NY, United States
| | - Erna Mitaishvili
- College of Dentistry, Department of Molecular Pathobiology, New York University, New York, NY, United States
| | - Zhi-Wei Ye
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, United States
| | - Jie Zhang
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, United States
| | - Danyelle M Townsend
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Marta Giacomello
- Department of Biology, University of Padova, Padua, Italy.,Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Rodrigo S Lacruz
- College of Dentistry, Department of Molecular Pathobiology, New York University, New York, NY, United States
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22
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Souza Bomfim GH, Costiniti V, Li Y, Idaghdour Y, Lacruz RS. TRPM7 activation potentiates SOCE in enamel cells but requires ORAI. Cell Calcium 2020; 87:102187. [PMID: 32146159 DOI: 10.1016/j.ceca.2020.102187] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/26/2020] [Accepted: 02/26/2020] [Indexed: 12/21/2022]
Abstract
Calcium (Ca2+) release-activated Ca2+ (CRAC) channels mediated by STIM1/2 and ORAI (ORAI1-3) proteins form the dominant store-operated Ca2+ entry (SOCE) pathway in a wide variety of cells. Among these, the enamel-forming cells known as ameloblasts rely on CRAC channel function to enable Ca2+ influx, which is important for enamel mineralization. This key role of the CRAC channel is supported by human mutations and animal models lacking STIM1 and ORAI1, which results in enamel defects and hypomineralization. A number of recent reports have highlighted the role of the chanzyme TRPM7 (transient receptor potential melastanin 7), a transmembrane protein containing an ion channel permeable to divalent cations (Mg2+, Ca2+), as a modulator of SOCE. This raises the question as to whether TRPM7 should be considered an alternative route for Ca2+ influx, or if TRPM7 modifies CRAC channel activity in enamel cells. To address these questions, we monitored Ca2+ influx mediated by SOCE using the pharmacological TRPM7 activator naltriben and the inhibitor NS8593 in rat primary enamel cells and in the murine ameloblast cell line LS8 cells stimulated with thapsigargin. We also measured Ca2+ dynamics in ORAI1/2-deficient (shOrai1/2) LS8 cells and in cells with siRNA knock-down of Trpm7. We found that primary enamel cells stimulated with the TRPM7 activator potentiated Ca2+ influx via SOCE compared to control cells. However, blockade of TRPM7 with NS8593 did not decrease the SOCE peak. Furthermore, activation of TRPM7 in shOrai1/2 LS8 cells lacking SOCE failed to elicit Ca2+ influx, and Trpm7 knock-down had no effect on SOCE. Taken together, our data suggest that TRPM7 is a positive modulator of SOCE potentiating Ca2+ influx in enamel cells, but its function is fully dependent on the prior activation of the ORAI channels.
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Affiliation(s)
- Guilherme H Souza Bomfim
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Veronica Costiniti
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Yi Li
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Youssef Idaghdour
- Biology Program, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, 10010, USA.
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23
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Lepperdinger U, Maurer E, Witsch-Baumgartner M, Stigler R, Zschocke J, Lussi A, Kapferer-Seebacher I. Expanding the phenotype of hypomaturation amelogenesis imperfecta due to a novel SLC24A4 variant. Clin Oral Investig 2020; 24:3519-3525. [PMID: 32034543 DOI: 10.1007/s00784-020-03222-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 01/23/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVES Biallelic variants in solute carrier family 24 member 4 (SLC24A4) have been previously reported to cause non-syndromic autosomal recessive amelogenesis imperfecta (AI) of the pigmented hypomaturation type (MIM #615887). We here describe a novel variant in SLC24A4 causing mild enamel hypomaturation defects also in heterozygous individuals. MATERIALS AND METHODS In the present pedigree analysis, a large consanguineous Syrian family with AI of the hypomaturation type was investigated by clinical and dental evaluation, and exome and Sanger sequencing. Dental histological investigations of seven primary and two permanent teeth were performed. RESULTS Homozygous variants in SLC24A4 (c.1604G>A; p.Gly535Asp) were identified in five individuals with brown discolorations and irregular pits and grooves of the teeth. Severe attritions, occlusal abfractions, and the radiological lack of contrast between enamel and dentin point out a mineralization defect. Histological dental investigations confirmed the clinical diagnosis of AI of the hypomaturation type. In two heterozygous individuals, a mild hypomaturation defect was present with white and light brown enamel discolorations. CONCLUSIONS This is the first report of heterozygous SLC24A4 variants causing mild hypomaturation defects, providing confirmatory evidence that the function of SLC24A4 in calcium transport has a crucial role in the maturation stage of amelogenesis. CLINICAL RELEVANCE The present report is expanding the clinical phenotype of SLC24A4 variants to more severe forms of amelogenesis imperfecta. An autosomal-dominant inheritance pattern with mild clinical phenotypes in heterozygotes has to be considered.
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Affiliation(s)
- Ulrike Lepperdinger
- Department of Operative and Restorative Dentistry, Medical University of Innsbruck, Anichstraße 35, A-6020, Innsbruck, Austria
| | - Elisabeth Maurer
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
| | | | - Robert Stigler
- Department of Oral and Maxillofacial Surgery, Medical University Innsbruck, Innsbruck, Austria
| | - Johannes Zschocke
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Adrian Lussi
- Department of Operative Dentistry and Periodontology, Faculty of Dentistry, University Medical Centre, Freiburg, Germany
| | - Ines Kapferer-Seebacher
- Department of Operative and Restorative Dentistry, Medical University of Innsbruck, Anichstraße 35, A-6020, Innsbruck, Austria.
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24
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Racz R, Nagy A, Rakonczay Z, Dunavari EK, Gerber G, Varga G. Defense Mechanisms Against Acid Exposure by Dental Enamel Formation, Saliva and Pancreatic Juice Production. Curr Pharm Des 2019; 24:2012-2022. [PMID: 29769002 PMCID: PMC6225347 DOI: 10.2174/1381612824666180515125654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/30/2018] [Accepted: 05/08/2018] [Indexed: 12/16/2022]
Abstract
The pancreas, the salivary glands and the dental enamel producing ameloblasts have marked developmental, structural and functional similarities. One of the most striking similarities is their bicarbonate-rich secretory product, serving acid neutralization. An important difference between them is that while pancreatic juice and saliva are delivered into a lumen where they can be collected and analyzed, ameloblasts produce locally precipitating hydroxyapatite which cannot be easily studied. Interestingly, the ion and protein secretion by the pancreas, the salivary glands, and maturation ameloblasts are all two-step processes, of course with significant differences too. As they all have to defend against acid exposure by producing extremely large quantities of bicarbonate, the failure of this function leads to deteriorating consequences. The aim of the present review is to describe and characterize the defense mechanisms of the pancreas, the salivary glands and enamel-producing ameloblasts against acid exposure and to compare their functional capabilities to do this by producing bicarbonate.
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Affiliation(s)
- Robert Racz
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Akos Nagy
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs, Pecs, Hungary
| | - Zoltan Rakonczay
- Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - Erika Katalin Dunavari
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs, Pecs, Hungary
| | - Gabor Gerber
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Gabor Varga
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
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25
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Green DR, Schulte F, Lee KH, Pugach MK, Hardt M, Bidlack FB. Mapping the Tooth Enamel Proteome and Amelogenin Phosphorylation Onto Mineralizing Porcine Tooth Crowns. Front Physiol 2019; 10:925. [PMID: 31417410 PMCID: PMC6682599 DOI: 10.3389/fphys.2019.00925] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/09/2019] [Indexed: 01/13/2023] Open
Abstract
Tooth enamel forms in an ephemeral protein matrix where changes in protein abundance, composition and posttranslational modifications are critical to achieve healthy enamel properties. Amelogenin (AMELX) with its splice variants is the most abundant enamel matrix protein, with only one known phosphorylation site at serine 16 shown in vitro to be critical for regulating mineralization. The phosphorylated form of AMELX stabilizes amorphous calcium phosphate, while crystalline hydroxyapatite forms in the presence of the unphosphorylated protein. While AMELX regulates mineral transitions over space and time, it is unknown whether and when un-phosphorylated amelogenin occurs during enamel mineralization. This study aims to reveal the spatiotemporal distribution of the cleavage products of the most abundant AMLEX splice variants including the full length P173, the shorter leucine-rich amelogenin protein (LRAP), and the exon 4-containing P190 in forming enamel, all within the context of the changing enamel matrix proteome during mineralization. We microsampled permanent pig molars, capturing known stages of enamel formation from both crown surface and inner enamel. Nano-LC-MS/MS proteomic analyses after tryptic digestion rendered more than 500 unique protein identifications in enamel, dentin, and bone. We mapped collagens, keratins, and proteolytic enzymes (CTSL, MMP2, MMP10) and determined distributions of P173, LRAP, and P190 products, the enamel proteins enamelin (ENAM) and ameloblastin (AMBN), and matrix-metalloprotease-20 (MMP20) and kallikrein-4 (KLK4). All enamel proteins and KLK4 were near-exclusive to enamel and in excellent agreement with published abundance levels. Phosphorylated P173 and LRAP products decreased in abundance from recently deposited matrix toward older enamel, mirrored by increasing abundances of testicular acid phosphatase (ACPT). Our results showed that hierarchical clustering analysis of secretory enamel links closely matching distributions of unphosphorylated P173 and LRAP products with ACPT and non-traditional amelogenesis proteins, many associated with enamel defects. We report higher protein diversity than previously published and Gene Ontology (GO)-defined protein functions related to the regulation of mineral formation in secretory enamel (e.g., casein α-S1, CSN1S1), immune response in erupted enamel (e.g., peptidoglycan recognition protein, PGRP), and phosphorylation. This study presents a novel approach to characterize and study functional relationships through spatiotemporal mapping of the ephemeral extracellular matrix proteome.
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Affiliation(s)
- Daniel R Green
- The Forsyth Institute, Cambridge, MA, United States.,Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, United States
| | | | - Kyu-Ha Lee
- The Forsyth Institute, Cambridge, MA, United States.,Department of Oral Health Policy and Epidemiology, Harvard School of Dental Medicine, Boston, MA, United States
| | - Megan K Pugach
- The Forsyth Institute, Cambridge, MA, United States.,Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, United States
| | - Markus Hardt
- The Forsyth Institute, Cambridge, MA, United States.,Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, United States
| | - Felicitas B Bidlack
- The Forsyth Institute, Cambridge, MA, United States.,Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, United States
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26
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Said R, Zheng L, Saunders T, Zeidler M, Papagerakis S, Papagerakis P. Generation of Amelx-iCre Mice Supports Ameloblast-Specific Role for Stim1. J Dent Res 2019; 98:1002-1010. [PMID: 31329049 DOI: 10.1177/0022034519858976] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The identification and targeting of the molecular pathways regulating amelogenesis is an ongoing challenge in dental research, and progress has been restricted by the limited number of genetic tools available to study gene function in ameloblasts. Here, we generated 4 transgenic Cre-driver mouse lines that express improved Cre (iCre)-recombinase from the locus of the mouse ameloblast-specific gene amelogenin X (Amelx-iCre) with a large (250-kb) bacterial artificial chromosome DNA vector. All 4 Amelx-iCre transgenic lines were bred with ROSA26 reporter mice to characterize the iCre developmental pattern with the LacZ gene encoding β-galactosidase enzyme activity assay and Cre protein immunohistochemistry. From the 4 generated transgenic lines, 2 were selected for further analysis because they expressed a high amount of Cre recombinase exclusively in ameloblasts and showed developmental stage- and cell-specific β-galactosidase activity mimicking the endogenous amelogenin expression. To test the functionality of the selected transgenic models, we bred the 2 Amelx-iCre mice lines with stromal interaction molecule 1 (Stim1) floxed mice to generate ameloblast-specific Stim1 conditional knockout mice (Stim1 cKO). STIM1 protein serves as one of the main calcium sensors in ameloblasts and plays a major role in enamel mineralization and ameloblast differentiation. Amelx-iCre mice displayed exclusive CRE-mediated recombination in incisor and molar ameloblasts. Stim1 cKO mice showed a severely defected enamel phenotype, including reduced structural integrity concomitant with increased attrition and smaller teeth. The phenotype and genotype of the Amelx-iCre/Stim1 cKO showed significant differences with the previously reported Ker14-Cre/Stim1 cKO, highlighting the need for cell- and stage-specific Cre lines for an accurate phenotype-genotype comparison. Furthermore, our model has the advantage of carrying the entire Amelx gene locus rather than being limited to an Amelx partial promoter construct, which greatly enhances the stability and the specificity of our Cre expression. As such, the Amelx-iCre transgenic lines that we developed may serve as a powerful tool for targeting ameloblast-specific gene expression in future investigations.
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Affiliation(s)
- R Said
- 1 Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.,2 College of Dentistry, University of Saskatchewan, Saskatoon, SK, Canada
| | - L Zheng
- 3 Department of Orthodontics, School of Dentistry, Ohio State University, Columbus, OH, USA
| | - T Saunders
- 4 Transgenic Animal Model Core, University of Michigan, Ann Arbor, MI, USA
| | - M Zeidler
- 4 Transgenic Animal Model Core, University of Michigan, Ann Arbor, MI, USA
| | - S Papagerakis
- 5 Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of Michigan, Ann Arbor, MI, USA.,6 Department of Surgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - P Papagerakis
- 1 Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.,2 College of Dentistry, University of Saskatchewan, Saskatoon, SK, Canada.,7 Department of Cariology, Restorative Sciences, and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
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27
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Robinson LJ, Blair HC, Barnett JB, Soboloff J. The roles of Orai and Stim in bone health and disease. Cell Calcium 2019; 81:51-58. [PMID: 31201955 PMCID: PMC7181067 DOI: 10.1016/j.ceca.2019.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/04/2019] [Accepted: 06/04/2019] [Indexed: 01/17/2023]
Abstract
Orai and Stim proteins are the mediators of calcium release-activated calcium signaling and are important in the regulation of bone homeostasis and disease. This includes separate regulatory systems controlling mesenchymal stem cell differentiation to form osteoblasts, which make bone, and differentiation and regulation of osteoclasts, which resorb bone. These systems will be described separately, and their integration and relation to other systems, including Orai and Stim in teeth, will be briefly discussed at the end of this review.
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Affiliation(s)
- Lisa J Robinson
- Department of Pathology, Anatomy, and Laboratory Medicine, West Virginia University School of Medicine, Morgantown WV 26505, United States; Department of Microbiology, Immunology, and Cell Biology, West Virginia University School of Medicine, Morgantown WV 26505, United States.
| | - Harry C Blair
- Veteran's Affairs Medical Center, Pittsburgh PA 15206, United States; Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - John B Barnett
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University School of Medicine, Morgantown WV 26505, United States
| | - Jonathan Soboloff
- Fels Institute for Cancer Research and Molecular Biology and the Department of Medical Genetics and Molecular Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, United States.
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28
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Arid J, Oliveira DB, Evangelista SS, Vasconcelos KRF, Dutra ALT, de Oliveira SS, de Queiroz AM, Nelson-Filho P, Vieira AR, Küchler EC. Oestrogen receptor alpha, growth hormone receptor, and developmental defect of enamel. Int J Paediatr Dent 2019; 29:29-35. [PMID: 30341791 DOI: 10.1111/ipd.12434] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Oestrogen (ES) and growth hormone (GH) are hormones that may have a role in caries aetiology and developmental defects of enamel (DDE) since their receptors (ERs and GHR) are expressed during amelogenesis. AIM To evaluate whether genetic polymorphisms in the genes that codify the ERα (ESR1) and GHR are associated with caries experience and DDE in children. DESIGN Two hundred and sixteen children of both genders, aged 9-12 years, were examined and classified according to caries and DDE phenotype. Genomic DNA was extracted from buccal cells in saliva. Genetic polymorphisms in ERS1 (rs1884051 and rs12154178) and GHR (rs297305, rs2940913, rs2910875, and rs1509460) were genotyped using TaqMan chemistry. Data were analysed by PLINK, while the chi-square test was used to compare allele and genotype distributions (alpha of 5%). RESULTS A total of 131 children (60.7%) had caries experience, and 43 (19.9%) presented DDE. Genotype and allele distributions were not associated with caries experience (P > 0.05). Genotype and allele distributions between DDE, affected and unaffected, were associated with the polymorphism rs12154178 in ESR1 (P = 0.01 and P = 0.001, respectively) and with the polymorphism rs1509460 in GHR (P = 0.05 and P = 0.02, respectively). CONCLUSIONS Genetic polymorphisms in ERS1 (rs12154178) and GHR (rs1509460) are associated with DDE.
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Affiliation(s)
- Juliana Arid
- Department of Pediatric Dentistry, University of São Paulo, School of Dentistry of Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Daniela B Oliveira
- Department of Pediatric Dentistry, Federal University of Alfenas, Alfenas, Minas Gerais, Brazil
| | - Silvane S Evangelista
- Department of Pediatric Dentistry, University of São Paulo, School of Dentistry of Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Katia R F Vasconcelos
- Department of Pediatric Dentistry, University of São Paulo, School of Dentistry of Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - André L T Dutra
- Department of Dentistry, State University of Amazonas, Manaus, Amazonas, Brazil
| | - Sara S de Oliveira
- Department of Dentistry, State University of Amazonas, Manaus, Amazonas, Brazil
| | - Alexandra M de Queiroz
- Department of Pediatric Dentistry, University of São Paulo, School of Dentistry of Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Paulo Nelson-Filho
- Department of Pediatric Dentistry, University of São Paulo, School of Dentistry of Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Alexandre R Vieira
- Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Erika C Küchler
- Department of Pediatric Dentistry, University of São Paulo, School of Dentistry of Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
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29
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Beck L. Expression and function of Slc34 sodium-phosphate co-transporters in skeleton and teeth. Pflugers Arch 2018; 471:175-184. [PMID: 30511265 DOI: 10.1007/s00424-018-2240-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/22/2018] [Accepted: 11/23/2018] [Indexed: 12/20/2022]
Abstract
Under normal physiological condition, the biomineralization process is limited to skeletal tissues and teeth and occurs throughout the individual's life. Biomineralization is an actively regulated process involving the progressive mineralization of the extracellular matrix secreted by osteoblasts in bone or odontoblasts and ameloblasts in tooth. Although the detailed molecular mechanisms underlying the formation of calcium-phosphate apatite crystals are still debated, it is suggested that calcium and phosphate may need to be transported across the membrane of the mineralizing cell, suggesting a pivotal role of phosphate transporters in bone and tooth mineralization. In this context, this short review describes the current knowledge on the role of Slc34 Na+-phosphate transporters in skeletal and tooth mineralization.
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Affiliation(s)
- Laurent Beck
- INSERM, UMR 1229, RMeS, Regenerative Medicine and Skeleton, Faculté de Chirurgie Dentaire, Université de Nantes, ONIRIS, 1 place Alexis Ricordeau, 44042, Nantes, France. .,Université de Nantes, UFR Odontologie, 44042, Nantes, France.
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30
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Liu X, Li T, Tuo B. Physiological and Pathophysiological Relevance of the Anion Transporter Slc26a9 in Multiple Organs. Front Physiol 2018; 9:1197. [PMID: 30233393 PMCID: PMC6127633 DOI: 10.3389/fphys.2018.01197] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 08/08/2018] [Indexed: 02/05/2023] Open
Abstract
Transepithelial Cl- and HCO3- transport is crucial for the function of all epithelia, and HCO3- is a biological buffer that maintains acid-base homeostasis. In most epithelia, a series of Cl-/HCO3- exchangers and Cl- channels that mediate Cl- absorption and HCO3- secretion have been detected in the luminal and basolateral membranes. Slc26a9 belongs to the solute carrier 26 (Slc26) family of anion transporters expressed in the epithelia of multiple organs. This review summarizes the expression pattern and functional diversity of Slc26a9 in different systems based on all investigations performed thus far. Furthermore, the physical and functional interactions between Slc26a9 and cystic fibrosis transmembrane conductance regulator (CFTR) are discussed due to their overlapping expression pattern in multiple organs. Finally, we focus on the relationship between slc26a9 mutations and disease onset. An understanding of the physiological and pathophysiological relevance of Slc26a9 in multiple organs offers new possibilities for disease therapy.
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Affiliation(s)
- Xuemei Liu
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical University, Zunyi, China.,Digestive Disease Institute of Guizhou Province, Zunyi, China
| | - Taolang Li
- Department of Thyroid and Breast Surgery, Affiliated Hospital, Zunyi Medical University, Zunyi, China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical University, Zunyi, China.,Digestive Disease Institute of Guizhou Province, Zunyi, China
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31
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Nurbaeva MK, Eckstein M, Devotta A, Saint-Jeannet JP, Yule DI, Hubbard MJ, Lacruz RS. Evidence That Calcium Entry Into Calcium-Transporting Dental Enamel Cells Is Regulated by Cholecystokinin, Acetylcholine and ATP. Front Physiol 2018; 9:801. [PMID: 30013487 PMCID: PMC6036146 DOI: 10.3389/fphys.2018.00801] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/07/2018] [Indexed: 01/06/2023] Open
Abstract
Dental enamel is formed by specialized epithelial cells which handle large quantities of Ca2+ while producing the most highly mineralized tissue. However, the mechanisms used by enamel cells to handle bulk Ca2+ safely remain unclear. Our previous work contradicted the dogma that Ca2+ is ferried through the cytosol of Ca2+-transporting cells and instead suggested an organelle-based route across enamel cells. This new paradigm involves endoplasmic reticulum (ER)-associated Ca2+ stores and their concomitant refilling by store-operated Ca2+ entry (SOCE) mediated by Ca2+ release activated Ca2+ (CRAC) channels. Given that Ca2+ handling is maximal during the enamel-mineralization stage (maturation), we anticipated that SOCE would also be elevated then. Confirmation was obtained here using single-cell recordings of cytosolic Ca2+ concentration ([Ca2+]cyt) in rat ameloblasts. A candidate SOCE agonist, cholecystokinin (CCK), was found to be upregulated during maturation, with Cck transcript abundance reaching 30% of that in brain. CCK-receptor transcripts were also detected and Ca2+ imaging showed that CCK stimulation increased [Ca2+]cyt in a dose-responsive manner that was sensitive to CRAC-channel inhibitors. Similar effects were observed with two other SOCE activators, acetylcholine and ATP, whose receptors were also found in enamel cells. These results provide the first evidence of a potential regulatory system for SOCE in enamel cells and so strengthen the Ca2+ transcytosis paradigm for ER-based transport of bulk Ca2+. Our findings also implicate enamel cells as a new physiological target of CCK and raise the possibility of an auto/paracrine system for regulating Ca2+ transport.
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Affiliation(s)
- Meerim K Nurbaeva
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, United States
| | - Miriam Eckstein
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, United States
| | - Arun Devotta
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, United States
| | - Jean-Pierre Saint-Jeannet
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, United States
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, United States
| | - Michael J Hubbard
- Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, United States
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32
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Kim HE, Hong JH. The overview of channels, transporters, and calcium signaling molecules during amelogenesis. Arch Oral Biol 2018; 93:47-55. [PMID: 29803993 DOI: 10.1016/j.archoralbio.2018.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 05/18/2018] [Accepted: 05/19/2018] [Indexed: 01/02/2023]
Abstract
Enamel is a highly calcified tissue. Its formation requires a progressive and dynamic system for the regulation of electrolyte concentration by enamel epithelia. A critical function of enamel epithelial cells, ameloblasts, is the secretion and movement of electrolytes via various channels and transporters to develop the enamel tissue. Enamel formation generates protons, which need to be neutralised. Thus, ameloblasts possess a buffering system to sustain mineral accretion. Normal tooth formation involves stage-dependent net fluctuations in pH during amelogenesis. To date, all of our information about ion transporters in dental enamel tissue is based solely on immunostaining-expression techniques. This review critically evaluates the current understanding and recent discoveries and physiological role of ion channels and transporters, Mg2+ transporters, and Ca2+ regulatory proteins during amelogenesis in enamel formation. The ways in which ameloblasts modulate ions are discussed in the context of current research for developing a novel morphologic-functional model of enamel maturation.
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Affiliation(s)
- Hee-Eun Kim
- Department of Dental Hygiene, College of Health Science, Gachon University, 191 Hambangmoe-ro, Yeonsu-gu, Incheon, 21936, South Korea
| | - Jeong Hee Hong
- Department of Physiology, College of Medicine, Lee Gil Ya Cancer and Diabetes Institute, GAIHST, Gachon University, Incheon, 21999, South Korea.
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33
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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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Houari S, Babajko S, Loiodice S, Berdal A, Jedeon K. Micro-dissection of Enamel Organ from Mandibular Incisor of Rats Exposed to Environmental Toxicants. J Vis Exp 2018. [PMID: 29658923 DOI: 10.3791/57081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Enamel defects resulting from environmental conditions and ways of life are public health concerns because of their high prevalence. These defects result from altered activity of cells responsible for enamel synthesis named ameloblasts, which present in enamel organ. During amelogenesis, ameloblasts follow a specific and precise sequence of events of proliferation, differentiation, and death. A rat continually growing incisors is a suitable experimental model to study ameloblast activity and differentiation stages in physiological and pathological conditions. Here, we describe a reliable and consistent method to micro-dissect enamel organ of rats exposed to environmental toxicants. The micro-dissected dental epithelia contain secretion- and maturation-stage ameloblasts that may be used for qualitative experiments, such as immunohistochemistry assays and in situ hybridization, as well as for quantitative analyses such as RT-qPCR, RNA-seq, and Western blotting.
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Affiliation(s)
- Sophia Houari
- Institut National de la Santé et Recherche Médicale (INSERM) UMRS 1138, Paris-Diderot University, Pierre & Marie Curie University, Paris-Descartes University, Laboratory of Molecular Oral Pathophysiology, Cordeliers Research Centre; Unit of Formation and Research (UFR) of Odontology, Paris-Diderot University
| | - Sylvie Babajko
- Institut National de la Santé et Recherche Médicale (INSERM) UMRS 1138, Paris-Diderot University, Pierre & Marie Curie University, Paris-Descartes University, Laboratory of Molecular Oral Pathophysiology, Cordeliers Research Centre; Unit of Formation and Research (UFR) of Odontology, Paris-Diderot University;
| | - Sophia Loiodice
- Institut National de la Santé et Recherche Médicale (INSERM) UMRS 1138, Paris-Diderot University, Pierre & Marie Curie University, Paris-Descartes University, Laboratory of Molecular Oral Pathophysiology, Cordeliers Research Centre; Unit of Formation and Research (UFR) of Odontology, Paris-Diderot University
| | - Ariane Berdal
- Institut National de la Santé et Recherche Médicale (INSERM) UMRS 1138, Paris-Diderot University, Pierre & Marie Curie University, Paris-Descartes University, Laboratory of Molecular Oral Pathophysiology, Cordeliers Research Centre; Unit of Formation and Research (UFR) of Odontology, Paris-Diderot University
| | - Katia Jedeon
- Institut National de la Santé et Recherche Médicale (INSERM) UMRS 1138, Paris-Diderot University, Pierre & Marie Curie University, Paris-Descartes University, Laboratory of Molecular Oral Pathophysiology, Cordeliers Research Centre; Unit of Formation and Research (UFR) of Odontology, Paris-Diderot University
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Abstract
Amelogenesis (tooth enamel formation) is a biomineralization process consisting primarily of two stages (secretory stage and maturation stage) with unique features. During the secretory stage, the inner epithelium of the enamel organ (i.e., the ameloblast cells) synthesizes and secretes enamel matrix proteins (EMPs) into the enamel space. The protein-rich enamel matrix forms a highly organized architecture in a pH-neutral microenvironment. As amelogenesis transitions to maturation stage, EMPs are degraded and internalized by ameloblasts through endosomal-lysosomal pathways. Enamel crystallite formation is initiated early in the secretory stage, however, during maturation stage the more rapid deposition of calcium and phosphate into the enamel space results in a rapid expansion of crystallite length and mineral volume. During maturation-stage amelogenesis, the pH value of enamel varies considerably from slightly above neutral to acidic. Extracellular acid-base balance during enamel maturation is tightly controlled by ameloblast-mediated regulatory networks, which include significant synthesis and movement of bicarbonate ions from both the enamel papillary layer cells and ameloblasts. In this review we summarize the carbonic anhydrases and the carbonate transporters/exchangers involved in pH regulation in maturation-stage amelogenesis. Proteins that have been shown to be instrumental in this process include CA2, CA6, CFTR, AE2, NBCe1, SLC26A1/SAT1, SLC26A3/DRA, SLC26A4/PDS, SLC26A6/PAT1, and SLC26A7/SUT2. In addition, we discuss the association of miRNA regulation with bicarbonate transport in tooth enamel formation.
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Affiliation(s)
- Kaifeng Yin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, CSA103, Los Angeles, CA, 90033, USA
- Department of Orthodontics, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - Michael L Paine
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, CSA103, Los Angeles, CA, 90033, USA.
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36
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Varga G, DenBesten P, Rácz R, Zsembery Á. Importance of bicarbonate transport in pH control during amelogenesis - need for functional studies. Oral Dis 2017; 24:879-890. [PMID: 28834043 DOI: 10.1111/odi.12738] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 08/13/2017] [Indexed: 12/27/2022]
Abstract
Dental enamel, the hardest mammalian tissue, is produced by ameloblasts. Ameloblasts show many similarities to other transporting epithelia although their secretory product, the enamel matrix, is quite different. Ameloblasts direct the formation of hydroxyapatite crystals, which liberate large quantities of protons that then need to be buffered to allow mineralization to proceed. Buffering requires a tight pH regulation and secretion of bicarbonate by ameloblasts. Many investigations have used immunohistochemical and knockout studies to determine the effects of these genes on enamel formation, but up till recently very little functional data were available for mineral ion transport. To address this, we developed a novel 2D in vitro model using HAT-7 ameloblast cells. HAT-7 cells can be polarized and develop functional tight junctions. Furthermore, they are able to accumulate bicarbonate ions from the basolateral to the apical fluid spaces. We propose that in the future, the HAT-7 2D system along with similar cellular models will be useful to functionally model ion transport processes during amelogenesis. Additionally, we also suggest that similar approaches will allow a better understanding of the regulation of the cycling process in maturation-stage ameloblasts, and the pH sensory mechanisms, which are required to develop sound, healthy enamel.
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Affiliation(s)
- G Varga
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - P DenBesten
- Department of Orofacial Sciences, University of California, San Francisco, CA, USA
| | - R Rácz
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Á Zsembery
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
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37
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Lacruz RS, Habelitz S, Wright JT, Paine ML. DENTAL ENAMEL FORMATION AND IMPLICATIONS FOR ORAL HEALTH AND DISEASE. Physiol Rev 2017; 97:939-993. [PMID: 28468833 DOI: 10.1152/physrev.00030.2016] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 12/16/2022] Open
Abstract
Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function.
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Affiliation(s)
- Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Stefan Habelitz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - J Timothy Wright
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Michael L Paine
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
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38
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Furukawa Y, Haruyama N, Nikaido M, Nakanishi M, Ryu N, Oh-Hora M, Kuremoto K, Yoshizaki K, Takano Y, Takahashi I. Stim1 Regulates Enamel Mineralization and Ameloblast Modulation. J Dent Res 2017; 96:1422-1429. [PMID: 28732182 DOI: 10.1177/0022034517719872] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Loss-of-function mutations in the Ca2+ release-activated Ca2+ channel genes ORAI1 and STIM1 abolish store-operated Ca2+ entry (SOCE) and result in ectodermal dysplasia with amelogenesis imperfecta. However, because of the limited availability of patient tissue, analyses of enamel mineralization or possible changes in ameloblast function or morphology have not been possible. Here, we generated mice with ectodermal tissue-specific deletion of Stim1 ( Stim1 cKO [conditional knockout]), Stim2 ( Stim2 cKO), and Stim1 and Stim2 ( Stim1/2 cKO) and analyzed their enamel phenotypes as compared with those of control ( Stim1/2fl/fl) animals. Ablation of Stim1 and Stim1/2 but not Stim2 expression resulted in chalky enamel and severe attrition at the incisor tips and molar cusps. Stim1 and Stim1/2 cKO, but not Stim2 cKO, demonstrated inferior enamel mineralization with impaired structural integrity, whereas the shape of the teeth and enamel thickness appeared to be normal in all animals. The gene expression levels of the enamel matrix proteins Amelx and Ambn and the enamel matrix proteases Mmp20 and Klk4 were not altered by the abrogation of SOCE in Stim1/2 cKO mice. The morphology of ameloblasts during the secretory and maturation stages was not significantly altered in either the incisors or molars of the cKO animals. However, in Stim1 and Stim1/2 cKO incisors, the alternating modulation of maturation-stage ameloblasts between the smooth- and ruffle-ended cell types continued beyond the regular cycle and extended to the areas corresponding to the zone of postmodulation ameloblasts in the teeth of control animals. These results indicate that SOCE is essential for proper enamel mineralization, in which Stim1 plays a critical role during the maturation process.
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Affiliation(s)
- Y Furukawa
- 1 Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth, and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.,2 Institute of Decision Science Program for Sustainable Society, Kyushu University, Fukuoka, Japan
| | - N Haruyama
- 1 Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth, and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - M Nikaido
- 1 Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth, and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - M Nakanishi
- 1 Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth, and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - N Ryu
- 1 Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth, and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - M Oh-Hora
- 3 Division of Molecular Immunology, Research Center for Infectious Diseases, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - K Kuremoto
- 4 Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - K Yoshizaki
- 1 Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth, and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Y Takano
- 5 Department of Cell Biology and Neuroscience, School of Medicine, Juntendo University, Tokyo, Japan
| | - I Takahashi
- 1 Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth, and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
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39
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Lacruz RS. Enamel: Molecular identity of its transepithelial ion transport system. Cell Calcium 2017; 65:1-7. [PMID: 28389033 PMCID: PMC5944837 DOI: 10.1016/j.ceca.2017.03.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/14/2022]
Abstract
Enamel is the most calcified tissue in vertebrates. It differs from bone in a number of characteristics including its origin from ectodermal epithelium, lack of remodeling capacity by the enamel forming cells, and absence of collagen. The enamel-forming cells known as ameloblasts, choreograph first the synthesis of a unique protein-rich matrix, followed by the mineralization of this matrix into a tissue that is ∼95% mineral. To do this, ameloblasts arrange the coordinated movement of ions across a cell barrier while removing matrix proteins and monitoring extracellular pH using a variety of buffering systems to enable the growth of carbonated apatite crystals. Although our knowledge of these processes and the molecular identity of the proteins involved in transepithelial ion transport has increased in the last decade, it remains limited compared to other cells. Here we present an overview of the evolution and development of enamel, its differences with bone, and describe the ion transport systems associated with ameloblasts.
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Affiliation(s)
- Rodrigo S Lacruz
- Dept. Basic Science and Craniofacial Biology, New York University College of Dentistry, 345 East 24th Street, New York, NY 10010, United States.
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40
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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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Robertson SYT, Wen X, Yin K, Chen J, Smith CE, Paine ML. Multiple Calcium Export Exchangers and Pumps Are a Prominent Feature of Enamel Organ Cells. Front Physiol 2017; 8:336. [PMID: 28588505 PMCID: PMC5440769 DOI: 10.3389/fphys.2017.00336] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/08/2017] [Indexed: 12/11/2022] Open
Abstract
Calcium export is a key function for the enamel organ during all stages of amelogenesis. Expression of a number of ATPase calcium transporting, plasma membrane genes (ATP2B1-4/PMCA1-4), solute carrier SLC8A genes (sodium/calcium exchanger or NCX1-3), and SLC24A gene family members (sodium/potassium/calcium exchanger or NCKX1-6) have been investigated in the developing enamel organ in earlier studies. This paper reviews the calcium export pathways that have been described and adds novel insights to the spatiotemporal expression patterns of PMCA1, PMCA4, and NCKX3 during amelogenesis. New data are presented to show the mRNA expression profiles for the four Atp2b1-4 gene family members (PMCA1-4) in secretory-stage and maturation-stage rat enamel organs. These data are compared to expression profiles for all Slc8a and Slc24a gene family members. PMCA1, PMCA4, and NCKX3 immunolocalization data is also presented. Gene expression profiles quantitated by real time PCR show that: (1) PMCA1, 3, and 4, and NCKX3 are most highly expressed during secretory-stage amelogenesis; (2) NCX1 and 3, and NCKX6 are expressed during secretory and maturation stages; (3) NCKX4 is most highly expressed during maturation-stage amelogenesis; and (4) expression levels of PMCA2, NCX2, NCKX1, NCKX2, and NCKX5 are negligible throughout amelogenesis. In the enamel organ PMCA1 localizes to the basolateral membrane of both secretory and maturation ameloblasts; PMCA4 expression is seen in the basolateral membrane of secretory and maturation ameloblasts, and also cells of the stratum intermedium and papillary layer; while NCKX3 expression is limited to Tomes' processes, and the apical membrane of maturation-stage ameloblasts. These new findings are discussed in the perspective of data already present in the literature, and highlight the multiplicity of calcium export systems in the enamel organ needed to regulate biomineralization.
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Affiliation(s)
- Sarah Y T Robertson
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States
| | - Xin Wen
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States
| | - Kaifeng Yin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States
| | - Junjun Chen
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States.,Department of Oral Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of MedicineShanghai, China.,Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of MedicineShanghai, China
| | - Charles E Smith
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill UniversityMontreal, QC, Canada
| | - Michael L Paine
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States
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Yin K, Guo J, Lin W, Robertson SYT, Soleimani M, Paine ML. Deletion of Slc26a1 and Slc26a7 Delays Enamel Mineralization in Mice. Front Physiol 2017; 8:307. [PMID: 28559854 PMCID: PMC5432648 DOI: 10.3389/fphys.2017.00307] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/28/2017] [Indexed: 12/12/2022] Open
Abstract
Amelogenesis features two major developmental stages—secretory and maturation. During maturation stage, hydroxyapatite deposition and matrix turnover require delicate pH regulatory mechanisms mediated by multiple ion transporters. Several members of the Slc26 gene family (Slc26a1, Slc26a3, Slc26a4, Slc26a6, and Slc26a7), which exhibit bicarbonate transport activities, have been suggested by previous studies to be involved in maturation-stage amelogenesis, especially the key process of pH regulation. However, details regarding the functional role of these genes in enamel formation are yet to be clarified, as none of the separate mutant animal lines demonstrates any discernible enamel defects. Continuing with our previous investigation of Slc26a1−/− and Slc26a7−/− animal models, we generated a double-mutant animal line with the absence of both Slc26a1 and Slc26a7. We showed in the present study that the double-mutant enamel density was significantly lower in the regions that represent late maturation-, maturation- and secretory-stage enamel development in wild-type mandibular incisors. However, the “maturation” and “secretory” enamel microstructures in double-mutant animals resembled those observed in wild-type secretory and/or pre-secretory stages. Elemental composition analysis revealed a lack of mineral deposition and an accumulation of carbon and chloride in double-mutant enamel. Deletion of Slc26a1 and Slc26a7 did not affect the stage-specific morphology of the enamel organ. Finally, compensatory expression of pH regulator genes and ion transporters was detected in maturation-stage enamel organs of double-mutant animals when compared to wild-type. Combined with the findings from our previous study, these data indicate the involvement of SLC26A1and SLC26A7 as key ion transporters in the pH regulatory network during enamel maturation.
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Affiliation(s)
- Kaifeng Yin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA.,Department of Orthodontics, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
| | - Jing Guo
- Department of Endodontics, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
| | - Wenting Lin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
| | - Sarah Y T Robertson
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
| | - Manoocher Soleimani
- Department of Medicine, University of Cincinnati, Research Services, Veterans Affairs Medical CenterCincinnati, OH, USA
| | - Michael L Paine
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
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43
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Nurbaeva MK, Eckstein M, Feske S, Lacruz RS. Ca 2+ transport and signalling in enamel cells. J Physiol 2017; 595:3015-3039. [PMID: 27510811 PMCID: PMC5430215 DOI: 10.1113/jp272775] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/21/2016] [Indexed: 01/02/2023] Open
Abstract
Dental enamel is one of the most remarkable examples of matrix-mediated biomineralization. Enamel crystals form de novo in a rich extracellular environment in a stage-dependent manner producing complex microstructural patterns that are visually stunning. This process is orchestrated by specialized epithelial cells known as ameloblasts which themselves undergo striking morphological changes, switching function from a secretory role to a cell primarily engaged in ionic transport. Ameloblasts are supported by a host of cell types which combined represent the enamel organ. Fully mineralized enamel is the hardest tissue found in vertebrates owing its properties partly to the unique mixture of ionic species represented and their highly organized assembly in the crystal lattice. Among the main elements found in enamel, Ca2+ is the most abundant ion, yet how ameloblasts modulate Ca2+ dynamics remains poorly known. This review describes previously proposed models for passive and active Ca2+ transport, the intracellular Ca2+ buffering systems expressed in ameloblasts and provides an up-dated view of current models concerning Ca2+ influx and extrusion mechanisms, where most of the recent advances have been made. We also advance a new model for Ca2+ transport by the enamel organ.
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Affiliation(s)
- Meerim K. Nurbaeva
- Department of Basic Science and Craniofacial BiologyNew York University College of DentistryNew YorkUSA
| | - Miriam Eckstein
- Department of Basic Science and Craniofacial BiologyNew York University College of DentistryNew YorkUSA
| | - Stefan Feske
- Department of PathologyNew York University School of MedicineNew YorkNY10016USA
| | - Rodrigo S. Lacruz
- Department of Basic Science and Craniofacial BiologyNew York University College of DentistryNew YorkUSA
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44
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Johnson L, Ganss B, Wang A, Zirngibl RA, Johnson DE, Owen C, Bradley G, Voronov I. V-ATPases Containing a3 Subunit Play a Direct Role in Enamel Development in Mice. J Cell Biochem 2017; 118:3328-3340. [PMID: 28295540 DOI: 10.1002/jcb.25986] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/09/2017] [Indexed: 12/17/2022]
Abstract
Vacuolar H+ -ATPases (V-ATPases) are ubiquitous multisubunit proton pumps responsible for organellar pH maintenance. Mutations in the a3 subunit of V-ATPases cause autosomal recessive osteopetrosis, a rare disease due to impaired bone resorption. Patients with osteopetrosis also display dental anomalies, such as enamel defects; however, it is not clear whether these enamel abnormalities are a direct consequence of the a3 mutations. We investigated enamel mineralization, spatiotemporal expression of enamel matrix proteins and the a3 protein during tooth development using an osteopetrotic mouse model with a R740S point mutation in the V-ATPase a3 subunit. Histology revealed aberrations in both crown and root development, whereas SEM analysis demonstrated delayed enamel mineralization in homozygous animals. Enamel thickness and mineralization were significantly decreased in homozygous mice as determined by μCT analysis. The expression patterns of the enamel matrix proteins amelogenin, amelotin, and odontogenic ameloblast-associated protein (ODAM) suggested a delay in transition to the maturation stage in homozygous animals. Protein expression of the a3 subunit was detected in ameloblasts in all three genotypes, suggesting that a3-containing V-ATPases play a direct role in amelogenesis, and mutations in a3 delay transition from the secretory to the maturation stage, resulting in hypomineralized and hypoplastic enamel. J. Cell. Biochem. 118: 3328-3340, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Lisa Johnson
- Faculty of Dentistry, Department of Oral Pathology, University of Toronto, Toronto, Ontario, Canada.,Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Bernhard Ganss
- Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada.,Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Andrew Wang
- Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Ralph A Zirngibl
- Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Danielle E Johnson
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Celeste Owen
- Centre for Modeling Human Disease, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
| | - Grace Bradley
- Faculty of Dentistry, Department of Oral Pathology, University of Toronto, Toronto, Ontario, Canada
| | - Irina Voronov
- Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada
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45
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Küchler EC, Pecharki GD, Castro ML, Ramos J, Barbosa F, Brancher JA, Vieira AR, Gerlach RF, Trevilatto PC. Genes Involved in the Enamel Development Are Associated with Calcium and Phosphorus Level in Saliva. Caries Res 2017; 51:225-230. [PMID: 28395292 DOI: 10.1159/000450764] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 09/09/2016] [Indexed: 01/24/2023] Open
Abstract
Saliva components play a crucial role in the integrity of the dental enamel and in caries susceptibility. The saliva characteristics are controlled by many factors, including genetic factors. Therefore, this study aimed to evaluate the association between the genetic variations in genes expressed in enamel development with calcium and phosphorus levels in saliva. We collected 276 unrelated 12-year-old children from private and public schools. Saliva was collected for DNA extraction from oral cells and for measurement of calcium and phosphorus. Inductively coupled plasma-mass spectrometry determined calcium and phosphorus levels in whole saliva. Fifteen genetic variations in 9 genes were analyzed. The genotype was determined by real-time polymerase chain reactions. Data were analyzed using Plink with an alpha of 5%. Genetic variations in AMELX, AMNB and ESRRB were associated with the calcium level in saliva (p < 0.05). A borderline association was observed in ENAM allele distribution shown with phosphate level in saliva (p = 0.049). In conclusion, our results are the first to report that genetic variations contribute to calcium and phosphorus levels in saliva.
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Affiliation(s)
- Erika Calvano Küchler
- Department of Pediatric Dentistry, Ribeirao Preto Dental School, Faculty of Pharmacy of Ribeirao Preto, USP - University of Sao Paulo, Ribeirao Preto, Brazil
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46
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MiR-153 Regulates Amelogenesis by Targeting Endocytotic and Endosomal/lysosomal Pathways-Novel Insight into the Origins of Enamel Pathologies. Sci Rep 2017; 7:44118. [PMID: 28287144 PMCID: PMC5347039 DOI: 10.1038/srep44118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 02/03/2017] [Indexed: 12/15/2022] Open
Abstract
Amelogenesis imperfecta (AI) is group of inherited disorders resulting in enamel pathologies. The involvement of epigenetic regulation in the pathogenesis of AI is yet to be clarified due to a lack of knowledge about amelogenesis. Our previous genome-wide microRNA and mRNA transcriptome analyses suggest a key role for miR-153 in endosome/lysosome-related pathways during amelogenesis. Here we show that miR-153 is significantly downregulated in maturation ameloblasts compared with secretory ameloblasts. Within ameloblast-like cells, upregulation of miR-153 results in the downregulation of its predicted targets including Cltc, Lamp1, Clcn4 and Slc4a4, and a number of miRNAs implicated in endocytotic pathways. Luciferase reporter assays confirmed the predicted interactions between miR-153 and the 3'-UTRs of Cltc, Lamp1 (in a prior study), Clcn4 and Slc4a4. In an enamel protein intake assay, enamel cells transfected with miR-153 show a decreased ability to endocytose enamel proteins. Finally, microinjection of miR-153 in the region of mouse first mandibular molar at postnatal day 8 (PN8) induced AI-like pathologies when the enamel development reached maturity (PN12). In conclusion, miR-153 regulates maturation-stage amelogenesis by targeting key genes involved in the endocytotic and endosomal/lysosomal pathways, and disruption of miR-153 expression is a potential candidate etiologic factor contributing to the occurrence of AI.
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Abstract
Hypomineralization of developing enamel is associated with changes in ameloblast modulation during the maturation stage. Modulation (or pH cycling) involves the cyclic transformation of ruffle-ended (RE) ameloblasts facing slightly acidic enamel into smooth-ended (SE) ameloblasts near pH-neutral enamel. The mechanism of ameloblast modulation is not clear. Failure of ameloblasts of Cftr-null and anion exchanger 2 ( Ae2)-null mice to transport Cl- into enamel acidifies enamel, prevents modulation, and reduces mineralization. It suggests that pH regulation is critical for modulation and for completion of enamel mineralization. This report presents a review of the major types of transmembrane molecules that ameloblasts express to transport calcium to form crystals and bicarbonates to regulate pH. The type of transporter depends on the developmental stage. Modulation is proposed to be driven by the pH of enamel fluid and the compositional and/or physicochemical changes that result from increased acidity, which may turn RE ameloblasts into SE mode. Amelogenins delay outgrowth of crystals and keep the intercrystalline space open for diffusion of mineral ions into complete depth of enamel. Modulation enables stepwise removal of amelogenins from the crystal surface, their degradation, and removal from the enamel. Removal of matrix allows slow expansion of crystals. Modulation also reduces the stress that ameloblasts experience when exposed to high acid levels generated by mineral formation or by increased intracellular Ca2+. By cyclically interrupting Ca2+ transport by RE ameloblasts and their transformation into SE ameloblasts, proton production ceases shortly and enables the ameloblasts to recover. Modulation also improves enamel crystal quality by selectively dissolving immature Ca2+-poor crystals, removing impurities as Mg2+ and carbonates, and recrystallizing into more acid-resistant crystals.
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Affiliation(s)
- A L J J Bronckers
- 1 Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute, Amsterdam, Netherlands
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48
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Seymen F, Kim YJ, Lee YJ, Kang J, Kim TH, Choi H, Koruyucu M, Kasimoglu Y, Tuna EB, Gencay K, Shin TJ, Hyun HK, Kim YJ, Lee SH, Lee ZH, Zhang H, Hu JCC, Simmer JP, Cho ES, Kim JW. Recessive Mutations in ACPT, Encoding Testicular Acid Phosphatase, Cause Hypoplastic Amelogenesis Imperfecta. Am J Hum Genet 2016; 99:1199-1205. [PMID: 27843125 PMCID: PMC5097978 DOI: 10.1016/j.ajhg.2016.09.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 09/26/2016] [Indexed: 11/25/2022] Open
Abstract
Amelogenesis imperfecta (AI) is a heterogeneous group of genetic disorders affecting tooth enamel. The affected enamel can be hypoplastic and/or hypomineralized. In this study, we identified ACPT (testicular acid phosphatase) biallelic mutations causing non-syndromic, generalized hypoplastic autosomal-recessive amelogenesis imperfecta (AI) in individuals from six apparently unrelated Turkish families. Families 1, 4, and 5 were affected by the homozygous ACPT mutation c.713C>T (p.Ser238Leu), family 2 by the homozygous ACPT mutation c.331C>T (p.Arg111Cys), family 3 by the homozygous ACPT mutation c.226C>T (p.Arg76Cys), and family 6 by the compound heterozygous ACPT mutations c.382G>C (p.Ala128Pro) and 397G>A (p.Glu133Lys). Analysis of the ACPT crystal structure suggests that these mutations damaged the activity of ACPT by altering the sizes and charges of key amino acid side chains, limiting accessibility of the catalytic core, and interfering with homodimerization. Immunohistochemical analysis confirmed localization of ACPT in secretory-stage ameloblasts. The study results provide evidence for the crucial function of ACPT during amelogenesis.
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Yamaguti PM, Neves FDAR, Hotton D, Bardet C, de La Dure-Molla M, Castro LC, Scher MDC, Barbosa ME, Ditsch C, Fricain JC, de La Faille R, Figueres ML, Vargas-Poussou R, Houillier P, Chaussain C, Babajko S, Berdal A, Acevedo AC. Amelogenesis imperfecta in familial hypomagnesaemia and hypercalciuria with nephrocalcinosis caused by CLDN19 gene mutations. J Med Genet 2016; 54:26-37. [PMID: 27530400 DOI: 10.1136/jmedgenet-2016-103956] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/15/2016] [Accepted: 07/27/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Amelogenesis imperfecta (AI) is a group of genetic diseases characterised by tooth enamel defects. AI was recently described in patients with familial hypercalciuria and hypomagnesaemia with nephrocalcinosis (FHHNC) caused by CLDN16 mutations. In the kidney, claudin-16 interacts with claudin-19 to control the paracellular passage of calcium and magnesium. FHHNC can be linked to mutations in both genes. Claudin-16 was shown to be expressed during amelogenesis; however, no data are available on claudin-19. Moreover, the enamel phenotype of patients with CLDN19 mutations has never been described. In this study, we describe the clinical and genetic features of nine patients with FHHNC carrying CLDN19 mutations and the claudin-19 expression profile in rat ameloblasts. METHODS Six FHHNC Brazilian patients were subjected to mutational analysis. Three additional French patients were recruited for orodental characterisation. The expression profile of claudin-19 was evaluated by RT-qPCR and immunofluorescence using enamel epithelium from rat incisors. RESULTS All patients presented AI at different degrees of severity. Two new likely pathogenic variations in CLDN19 were found: p.Arg200Gln and p.Leu90Arg. RT-qPCR revealed low Cldn19 expression in ameloblasts. Confocal analysis indicated that claudin-19 was immunolocalised at the distal poles of secretory and maturing ameloblasts. CONCLUSIONS For the first time, it was demonstrated that AI is associated with FHHNC in patients carrying CLDN19 mutations. The data suggest claudin-19 as an additional determinant in enamel formation. Indeed, the coexistence of hypoplastic and hypomineralised AI in the patients was consistent with claudin-19 expression in both secretory and maturation stages. Additional indirect systemic effects cannot be excluded.
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Affiliation(s)
- Paulo Marcio Yamaguti
- Faculty of Health Sciences, Division of Dentistry, Oral Care Center for Inherited Diseases, University Hospital of Brasilia, University of Brasilia, Brasilia, Brazil.,Faculty of Health Sciences, Laboratory of Oral Histopathology, University of Brasilia, Brasilia, Brazil
| | | | - Dominique Hotton
- Centre de Recherche des Cordeliers, University Paris-Diderot, INSERM UMR_S1138, Equipe Physiopathologie Orale Moléculaire, Paris, France
| | - Claire Bardet
- EA 2496, Laboratory Orofacial Pathologies, Imaging and Biotherapies, Dental School, University Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Muriel de La Dure-Molla
- INSERM UMR_S1163, Bases moléculaires et physiopathologiques des ostéochondrodysplasies, Institut Imagine, Necker, Paris, France.,AP-HP, Referral Center for Rare Buccal and Facial Dysmorphologies CRMR MAFACE, Hôpital Rothschild, Paris, France
| | - Luiz Claudio Castro
- Unit of Pediatric Endocrinology, University Hospital of Brasilia, Brasilia, Brazil
| | | | | | | | - Jean-Christophe Fricain
- CHU Bordeaux, Dental school, U1026 Tissue Bioengineering, University of Bordeaux/Inserm, Bordeaux, France
| | - Renaud de La Faille
- Department of Nephrology, Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France
| | - Marie-Lucile Figueres
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, CNRS ERL_8228, Paris, France
| | - Rosa Vargas-Poussou
- AP-HP, Department of Genetics, Reference Center of Children and Adult Renal Hereditary Diseases (MARHEA), Hôpital European Georges Pompidou, Paris, France
| | - Pascal Houillier
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, CNRS ERL_8228, Paris, France.,AP-HP, Department of Genetics, Reference Center of Children and Adult Renal Hereditary Diseases (MARHEA), Hôpital European Georges Pompidou, Paris, France
| | - Catherine Chaussain
- EA 2496, Laboratory Orofacial Pathologies, Imaging and Biotherapies, Dental School, University Paris Descartes, Sorbonne Paris Cité, Paris, France.,AP-HP, Department of Genetics, Reference Center of Children and Adult Renal Hereditary Diseases (MARHEA), Hôpital European Georges Pompidou, Paris, France
| | - Sylvie Babajko
- Centre de Recherche des Cordeliers, University Paris-Diderot, INSERM UMR_S1138, Equipe Physiopathologie Orale Moléculaire, Paris, France
| | - Ariane Berdal
- Centre de Recherche des Cordeliers, University Paris-Diderot, INSERM UMR_S1138, Equipe Physiopathologie Orale Moléculaire, Paris, France.,AP-HP, Referral Center for Rare Buccal and Facial Dysmorphologies CRMR MAFACE, Hôpital Rothschild, Paris, France
| | - Ana Carolina Acevedo
- Faculty of Health Sciences, Division of Dentistry, Oral Care Center for Inherited Diseases, University Hospital of Brasilia, University of Brasilia, Brasilia, Brazil.,Faculty of Health Sciences, Laboratory of Oral Histopathology, University of Brasilia, Brasilia, Brazil
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50
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Su Y, Fan Z, Wu X, Li Y, Wang F, Zhang C, Wang J, Du J, Wang S. Genome-wide DNA methylation profile of developing deciduous tooth germ in miniature pigs. BMC Genomics 2016; 17:134. [PMID: 26911717 PMCID: PMC4766650 DOI: 10.1186/s12864-016-2485-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 02/17/2016] [Indexed: 12/28/2022] Open
Abstract
Background DNA methylation is an important epigenetic modification critical to the regulation of gene expression during development. To date, little is known about the role of DNA methylation in tooth development in large animal models. Thus, we carried out a comparative genomic analysis of genome-wide DNA methylation profiles in E50 and E60 tooth germ from miniature pigs using methylated DNA immunoprecipitation-sequencing (MeDIP-seq). Results We observed different DNA methylation patterns during the different developmental stages of pig tooth germ. A total of 2469 differentially methylated genes were identified. Functional analysis identified several signaling pathways and 104 genes that may be potential key regulators of pig tooth development from E50 to E60. Conclusions The present study provided a comprehensive analysis of the global DNA methylation pattern of tooth germ in miniature pigs and identified candidate genes that potentially regulate tooth development from E50 to E60. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2485-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yingying Su
- Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Tian Tan Xi Li No.4, Beijing, 100050, China.
| | - Zhipeng Fan
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Tian Tan Xi Li No.4, Beijing, 100050, China.
| | - Xiaoshan Wu
- Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Tian Tan Xi Li No.4, Beijing, 100050, China.
| | - Yang Li
- Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Tian Tan Xi Li No.4, Beijing, 100050, China.
| | - Fu Wang
- Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Tian Tan Xi Li No.4, Beijing, 100050, China.
| | - Chunmei Zhang
- Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Tian Tan Xi Li No.4, Beijing, 100050, China.
| | - Jinsong Wang
- Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Tian Tan Xi Li No.4, Beijing, 100050, China. .,Department of Biochemistry and Molecular Biology, Capital Medical University School of Basic Medical Sciences, You An Men Wai Xi Tou Tiao No.10, Beijing, 100069, China.
| | - Jie Du
- Department of Physiology and Pathophysiology, Beijing An Zhen Hospital the Key Laboratory of Remodeling-Related Cardiovascular Diseases, School of Basic Medical Sciences, Capital Medical University, You An Men Wai Xi Tou Tiao No.10, Beijing, 100069, China.
| | - Songlin Wang
- Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Tian Tan Xi Li No.4, Beijing, 100050, China. .,Department of Biochemistry and Molecular Biology, Capital Medical University School of Basic Medical Sciences, You An Men Wai Xi Tou Tiao No.10, Beijing, 100069, China.
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