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Mercado F, Vaquette C, Hamlet S, Ivanovski S. Enamel matrix derivative promotes new bone formation in xenograft assisted maxillary anterior ridge preservation-A randomized controlled clinical trial. Clin Oral Implants Res 2021; 32:732-744. [PMID: 33715279 DOI: 10.1111/clr.13742] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2021] [Indexed: 12/24/2022]
Abstract
OBJECTIVES To compare the effectiveness of deproteinized bovine bone mineral with 10% collagen alone (DBBMC) or with enamel matrix derivative (DBBMC-EMD) in ridge preservation. METHODS 42 maxillary anterior teeth were extracted and received either a DBBMC (control) or DBBMC-EMD (test) treatment protocol. CBCT taken before and 4 months after the extraction procedure was used to measure changes in alveolar ridge width (RW), buccal bone height (BH) and palatal bone height (PH). Bone cores were harvested during implant osteotomy preparation, and the samples processed histomorphometrically to assess the fraction of new bone (%NB), residual graft (%RG) and soft tissue matrix (%STM). RESULTS Overall, both treatment groups showed significant reductions in mean RW from baseline to 4 months after extraction, but no significant change in either mean BH or PH over this time. When CBCT measurements were analysed according to the initial thickness of the buccal wall (BT < 1 mm vs. BT ≥ 1 mm), significant reductions in all ridge dimensions (RW, BH and PH) were noted in the <1 mm BT group. Histomorphometrically, the DBBMC-EMD test group showed significantly increased new bone formation (%NB): (control = 16.5 ± 6.9% cf.; test = 45.1 ± 8.8%) with less residual graft (%RG): (control = 36.8 ± 8.8% cf.; test = 20.3 ± 7.2%) compared to the DBBMC control group. CONCLUSIONS Both DBBMC alone and DBBMC-EMD treated sites 4 months after extraction lost RW but showed no significant change in BH or PH. Irrespective of treatment, maxillary anterior teeth with thick initial buccal walls (≥1 mm) exhibited less alveolar ridge reduction 4 months after treatment. The addition of EMD to DBBMC resulted in more new bone formation in the test group.
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Affiliation(s)
- Faustino Mercado
- School of Dentistry and Oral Health, Griffith University, Gold Coast, QLD, Australia.,School of Dentistry, University of Queensland, Brisbane, QLD, Australia
| | - Cedryck Vaquette
- School of Dentistry, University of Queensland, Brisbane, QLD, Australia
| | - Stephen Hamlet
- School of Dentistry and Oral Health, Griffith University, Gold Coast, QLD, Australia.,Menzies Health Institute, Griffith University, Gold Coast, QLD, Australia
| | - Sašo Ivanovski
- School of Dentistry, University of Queensland, Brisbane, QLD, Australia
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Kind L, Stevanovic S, Wuttig S, Wimberger S, Hofer J, Müller B, Pieles U. Biomimetic Remineralization of Carious Lesions by Self-Assembling Peptide. J Dent Res 2017; 96:790-797. [PMID: 28346861 DOI: 10.1177/0022034517698419] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Caries is the most common disease in the world. Great efforts have been undertaken for prevention and to identify a regenerative treatment solution for dental caries. Self-assembling β-sheet forming peptides have previously shown to form 3-dimensional fiber networks supporting tissue regeneration. In particular, the self-assembling peptide P11-4 has shown potential in the treatment and prevention of dental caries. It has previously been shown that application of monomeric P11-4 solution to early carious lesions can increase net mineral gain by forming de novo hydroxyapatite crystals. The hypothesis for the mode of action was that monomeric self-assembling peptide P11-4 diffuses into the subsurface lesion body and assembles therein into higher order fibrils, facilitating mineralization of the subsurface volume by mimicking the natural biomineralization of the tooth enamel, and it remains within the lesion body as a scaffold built-in by the newly formed hydroxyapatite. The aim of the present study was to investigate the mechanism of action of the self-assembling peptide P11-4 supporting mineralization of carious enamel. By various analytical methods, it could be shown that the self-assembling peptide P11-4 diffuses into the subsurface lesion, assembles into higher formed aggregates throughout the whole volume of the lesion, and supports nucleation of de novo hydroxyapatite nanocrystals and consequently results in increased mineral density within the subsurface carious lesion. The results showed that the application of self-assembling peptide P11-4 can facilitate the subsurface regeneration of the enamel lesion by supporting de novo mineralization in a similar mode of action as has been shown for the natural formation of dental enamel.
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Affiliation(s)
- L Kind
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - S Stevanovic
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - S Wuttig
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - S Wimberger
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - J Hofer
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - B Müller
- 2 Department of Biomedical Engineering, University of Basel, Biomaterials Science Center (BMC), Allschwil, Switzerland
| | - U Pieles
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
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3
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Stakkestad Ø, Lyngstadaas SP, Vondrasek J, Gordeladze JO, Reseland JE. Ameloblastin Peptides Modulates the Osteogenic Capacity of Human Mesenchymal Stem Cells. Front Physiol 2017; 8:58. [PMID: 28223942 PMCID: PMC5293776 DOI: 10.3389/fphys.2017.00058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 01/23/2017] [Indexed: 12/19/2022] Open
Abstract
During amelogenesis the extracellular enamel matrix protein AMBN is quickly processed into 17 kDa (N-terminus) and 23 kDa (C-terminus) fragments. In particular, alternatively spliced regions derived by exon 5/6 within the N-terminus region are known to be critical in biomineralization. Human mesenchymal stem cells (hMSC) also express and secrete AMBN, but it is unclear if this expression has effects on the hMSC themselves. If, as suggested from previous findings, AMBN act as a signaling molecule, such effects could influence hMSC growth and differentiation, as well as promoting the secretion of other signaling proteins like cytokines and chemokines. If AMBN is found to modulate stem cell behavior and fate, it will impact our understanding on how extracellular matrix molecules can have multiple roles during development ontogenesis, mineralization and healing of mesenchymal tissues. Here we show that synthetic peptides representing exon 5 promote hMSC proliferation. Interestingly, this effect is inhibited by the application of a 15 aa peptide representing the alternatively spliced start of exon 6. Both peptides also influence gene expression of RUNX2 and osteocalcin, and promote calcium deposition in cultures, indicating a positive influence on the osteogenic capacity of hMSC. We also show that the full-length AMBN-WT and N-terminus region enhance the secretion of RANTES, IP-10, and IL-8. In contrast, the AMBN C-terminus fragment and the exon 5 deleted AMBN (DelEx5) have no detectable effects on any of the parameters investigated. These findings suggest the signaling effect of AMBN is conveyed by processed products, whereas the effect on proliferation is differentially modulated through alternative splicing during gene expression.
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Affiliation(s)
- Øystein Stakkestad
- Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo Oslo, Norway
| | - Ståle P Lyngstadaas
- Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo Oslo, Norway
| | - Jiri Vondrasek
- Department of Bioinformatics, Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences Prague, Czechia
| | - Jan O Gordeladze
- Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo Oslo, Norway
| | - Janne Elin Reseland
- Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo Oslo, Norway
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Mazumder P, Prajapati S, Bapat R, Moradian-Oldak J. Amelogenin-Ameloblastin Spatial Interaction around Maturing Enamel Rods. J Dent Res 2016; 95:1042-8. [PMID: 27146703 PMCID: PMC4959624 DOI: 10.1177/0022034516645389] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Amelogenin and ameloblastin are 2 extracellular matrix proteins that are essential for the proper development of enamel. We recently reported that amelogenin and ameloblastin colocalized during the secretory stage of enamel formation when nucleation of enamel crystallites occurs. Direct interactions between the 2 proteins have been also demonstrated in our in vitro studies. Here, we explore interactions between their fragments during enamel maturation. We applied in vivo immunofluorescence imaging, quantitative co-localization analysis, and a new FRET (fluorescence resonance energy transfer) technique to demonstrate ameloblastin and amelogenin interaction in the maturing mouse enamel. Using immunochemical analysis of protein samples extracted from 8-d-old (P8) first molars from mice as a model for maturation-stage enamel, we identified the ~17-kDa ameloblastin (Ambn-N) and the TRAP (tyrosine-rich amelogenin peptide) fragments. We used Ambn-N18 and Ambn-M300 antibodies raised against the N-terminal and C-terminal segments of ameloblastin, as well as Amel-FL and Amel-C19 antibodies against full-length recombinant mouse amelogenin (rM179) and C-terminal amelogenin, respectively. In transverse sections, co-localization images of N-terminal fragments of amelogenin and ameloblastin around the prism boundary revealed the "fish net" pattern of the enamel matrix. Using in vivo FRET microscopy, we further demonstrated spatial interactions between amelogenin and ameloblastin N-terminal fragments. In the maturing mouse enamel, the association of these residual protein fragments created a discontinuity between enamel rods, which we suggest is important for support and maintenance of enamel rods and eventual contribution to unique enamel mechanical properties. We present data that support cooperative functions of enamel matrix proteins in mediating the structural hierarchy of enamel and that contribute to our efforts to design and develop enamel biomimetic material.
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Affiliation(s)
- P Mazumder
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - S Prajapati
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - R Bapat
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - J Moradian-Oldak
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
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Mazumder P, Prajapati S, Lokappa SB, Gallon V, Moradian-Oldak J. Analysis of co-assembly and co-localization of ameloblastin and amelogenin. Front Physiol 2014; 5:274. [PMID: 25120489 PMCID: PMC4110739 DOI: 10.3389/fphys.2014.00274] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/07/2014] [Indexed: 12/17/2022] Open
Abstract
Epithelially-derived ameloblasts secrete extracellular matrix proteins including amelogenin, enamelin, and ameloblastin. Complex intermolecular interactions among these proteins are believed to be important in controlling enamel formation. Here we provide in vitro and in vivo evidence of co-assembly and co-localization of ameloblastin with amelogenin using both biophysical and immunohistochemical methods. We performed co-localization studies using immunofluorescence confocal microscopy with paraffin-embedded tissue sections from mandibular molars of mice at 1, 5, and 8 days of age. Commercially-available ameloblastin antibody (M300) against mouse ameloblastin residues 107-407 and an antibody against full-length recombinant mouse (rM179) amelogenin were used. Ameloblastin-M300 clearly reacted along the secretory face of ameloblasts from days 1-8. Quantitative co-localization was analyzed (QCA) in several configurations by choosing appropriate regions of interest (ROIs). Analysis of ROIs along the secretory face of ameloblasts revealed that at day 1, very high percentages of both the ameloblastin and amelogenin co-localized. At day 8 along the ameloblast cells the percentage of co-localization remained high for the ameloblastin whereas co-localization percentage was reduced for amelogenin. Analysis of the entire thickness on day 8 revealed no significant co-localization of amelogenin and ameloblastin. With the progress of amelogenesis and ameloblastin degradation, there was a segregation of ameloblastin and co-localization with the C-terminal region decreased. CD spectra indicated that structural changes in ameloblastin occurred upon addition of amelogenin. Our data suggest that amelogenin-ameloblastin complexes may be the functional entities at the early stage of enamel mineralization.
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Affiliation(s)
| | | | | | | | - Janet Moradian-Oldak
- Division of Biomedical Sciences, Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, USA
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Jacques J, Hotton D, De la Dure-Molla M, Petit S, Asselin A, Kulkarni AB, Gibson CW, Brookes SJ, Berdal A, Isaac J. Tracking endogenous amelogenin and ameloblastin in vivo. PLoS One 2014; 9:e99626. [PMID: 24933156 PMCID: PMC4059656 DOI: 10.1371/journal.pone.0099626] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 05/16/2014] [Indexed: 01/05/2023] Open
Abstract
Research on enamel matrix proteins (EMPs) is centered on understanding their role in enamel biomineralization and their bioactivity for tissue engineering. While therapeutic application of EMPs has been widely documented, their expression and biological function in non-enamel tissues is unclear. Our first aim was to screen for amelogenin (AMELX) and ameloblastin (AMBN) gene expression in mandibular bones and soft tissues isolated from adult mice (15 weeks old). Using RT-PCR, we showed mRNA expression of AMELX and AMBN in mandibular alveolar and basal bones and, at low levels, in several soft tissues; eyes and ovaries were RNA-positive for AMELX and eyes, tongues and testicles for AMBN. Moreover, in mandibular tissues AMELX and AMBN mRNA levels varied according to two parameters: 1) ontogenic stage (decreasing with age), and 2) tissue-type (e.g. higher level in dental epithelial cells and alveolar bone when compared to basal bone and dental mesenchymal cells in 1 week old mice). In situ hybridization and immunohistodetection were performed in mandibular tissues using AMELX KO mice as controls. We identified AMELX-producing (RNA-positive) cells lining the adjacent alveolar bone and AMBN and AMELX proteins in the microenvironment surrounding EMPs-producing cells. Western blotting of proteins extracted by non-dissociative means revealed that AMELX and AMBN are not exclusive to mineralized matrix; they are present to some degree in a solubilized state in mandibular bone and presumably have some capacity to diffuse. Our data support the notion that AMELX and AMBN may function as growth factor-like molecules solubilized in the aqueous microenvironment. In jaws, they might play some role in bone physiology through autocrine/paracrine pathways, particularly during development and stress-induced remodeling.
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Affiliation(s)
- Jaime Jacques
- Laboratory of Molecular Oral Pathophysiology, INSERM UMRS 1138, Team Berdal, Cordeliers Research Center, Pierre and Marie Curie University - Paris 6, Paris Descartes University - Paris 5, Paris, France
- UFR d'Odontologie, Paris Diderot University - Paris 7, Paris, France
- Unit of Periodontology, Department of Stomatology, University of Talca, Talca, Chile
| | - Dominique Hotton
- Laboratory of Molecular Oral Pathophysiology, INSERM UMRS 1138, Team Berdal, Cordeliers Research Center, Pierre and Marie Curie University - Paris 6, Paris Descartes University - Paris 5, Paris, France
| | - Muriel De la Dure-Molla
- Laboratory of Molecular Oral Pathophysiology, INSERM UMRS 1138, Team Berdal, Cordeliers Research Center, Pierre and Marie Curie University - Paris 6, Paris Descartes University - Paris 5, Paris, France
- UFR d'Odontologie, Paris Diderot University - Paris 7, Paris, France
- Center of Rare Malformations of the Face and Oral Cavity (MAFACE), Hospital Rothschild, AP-HP, Paris, France
| | - Stephane Petit
- Laboratory of Molecular Oral Pathophysiology, INSERM UMRS 1138, Team Berdal, Cordeliers Research Center, Pierre and Marie Curie University - Paris 6, Paris Descartes University - Paris 5, Paris, France
| | - Audrey Asselin
- Laboratory of Molecular Oral Pathophysiology, INSERM UMRS 1138, Team Berdal, Cordeliers Research Center, Pierre and Marie Curie University - Paris 6, Paris Descartes University - Paris 5, Paris, France
| | - Ashok B. Kulkarni
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Carolyn Winters Gibson
- Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania, United States of America
| | - Steven Joseph Brookes
- Department of Oral Biology, School of Dentistry, University of Leeds, United Kingdom
| | - Ariane Berdal
- Laboratory of Molecular Oral Pathophysiology, INSERM UMRS 1138, Team Berdal, Cordeliers Research Center, Pierre and Marie Curie University - Paris 6, Paris Descartes University - Paris 5, Paris, France
- UFR d'Odontologie, Paris Diderot University - Paris 7, Paris, France
- Center of Rare Malformations of the Face and Oral Cavity (MAFACE), Hospital Rothschild, AP-HP, Paris, France
| | - Juliane Isaac
- Laboratory of Molecular Oral Pathophysiology, INSERM UMRS 1138, Team Berdal, Cordeliers Research Center, Pierre and Marie Curie University - Paris 6, Paris Descartes University - Paris 5, Paris, France
- Laboratory of Morphogenesis Molecular Genetics, Department of Developmental and Stem Cells Biology, Institut Pasteur, CNRS URA 2578, Paris, France
- * E-mail:
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Poulter JA, Murillo G, Brookes SJ, Smith CEL, Parry DA, Silva S, Kirkham J, Inglehearn CF, Mighell AJ. Deletion of ameloblastin exon 6 is associated with amelogenesis imperfecta. Hum Mol Genet 2014; 23:5317-24. [PMID: 24858907 PMCID: PMC4168819 DOI: 10.1093/hmg/ddu247] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Amelogenesis imperfecta (AI) describes a heterogeneous group of inherited dental enamel defects reflecting failure of normal amelogenesis. Ameloblastin (AMBN) is the second most abundant enamel matrix protein expressed during amelogenesis. The pivotal role of AMBN in amelogenesis has been confirmed experimentally using mouse models. However, no AMBN mutations have been associated with human AI. Using autozygosity mapping and exome sequencing, we identified genomic deletion of AMBN exon 6 in a second cousin consanguineous family with three of the six children having hypoplastic AI. The genomic deletion corresponds to an in-frame deletion of 79 amino acids, shortening the protein from 447 to 368 residues. Exfoliated primary teeth (unmatched to genotype) were available from family members. The most severely affected had thin, aprismatic enamel (similar to that reported in mice homozygous for Ambn lacking exons 5 and 6). Other teeth exhibited thicker but largely aprismatic enamel. One tooth had apparently normal enamel. It has been suggested that AMBN may function in bone development. No clinically obvious bone or other co-segregating health problems were identified in the family investigated. This study confirms for the first time that AMBN mutations cause non-syndromic human AI and that mouse models with disrupted Ambn function are valid.
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Affiliation(s)
- James A Poulter
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | | | | | - Claire E L Smith
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - David A Parry
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Sandra Silva
- Biology, Molecular Cellular Centre (CBCM), University of Costa Rica, San Pedro, Costa Rica
| | | | - Chris F Inglehearn
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Alan J Mighell
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK School of Dentistry, University of Leeds, Leeds LS2 9LU, UK
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Saito N, Ariyoshi W, Okinaga T, Kamegawa M, Matsukizono M, Akebiyama Y, Kitamura C, Nishihara T. Inhibitory effects of ameloblastin on epithelial cell proliferation. Arch Oral Biol 2014; 59:835-40. [PMID: 24859770 DOI: 10.1016/j.archoralbio.2014.05.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/05/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Ameloblastin is an enamel matrix protein expressed in several tissues. Many potential mechanisms have been identified by which ameloblastin functions as an extracellular matrix protein. However, the biological effects of ameloblastin on gingival epithelial cells remain unclear. In the present study, we established a novel system to purify recombinant human ameloblastin and clarified its biological functions in epithelial cells in vitro. DESIGN Recombinant human ameloblastin was isolated from COS-7 cells overexpressing HaloTag-fused human ameloblastin by the HaloTag system and then purified further by reverse-phase high-performance liquid chromatography. SCC-25 cells, derived from human oral squamous cell carcinoma, were treated with recombinant ameloblastin and then cell survival was assessed by a WST-1 assay. Cell cycle analysis was performed by flow cytometry. RESULTS The novel purification system allowed effective recovery of the recombinant ameloblastin proteins at a high purity. Recombinant ameloblastin protein was found to suppress the proliferation of SCC-25 cells. Flow cytometric analysis showed that ameloblastin treatment induced cell cycle arrest G1 phase. CONCLUSIONS We developed a procedure for production of highly purified recombinant human ameloblastin. Biological analyses suggest that ameloblastin induces cell cycle arrest in epithelial cells and regulates the progression of periodontitis.
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Affiliation(s)
- Noriko Saito
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan; Division of Pulp Biology, Operative Dentistry and Endodontics, Department of Cariology and Periodontology, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan
| | - Wataru Ariyoshi
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan.
| | - Toshinori Okinaga
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan
| | - Mariko Kamegawa
- Genenet Co., Ltd, 5-22-8, Tanotsu, Higashi-Ku, Fukuoka 813-0034, Japan
| | - Miho Matsukizono
- Genenet Co., Ltd, 5-22-8, Tanotsu, Higashi-Ku, Fukuoka 813-0034, Japan
| | - Yasuo Akebiyama
- Genenet Co., Ltd, 5-22-8, Tanotsu, Higashi-Ku, Fukuoka 813-0034, Japan
| | - Chiaki Kitamura
- Division of Pulp Biology, Operative Dentistry and Endodontics, Department of Cariology and Periodontology, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan
| | - Tatsuji Nishihara
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan
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Olivares-Navarrete R, Hyzy SL, Almaguer-Flores A, Mauth C, Gemperli AC, Boyan BD, Schwartz Z. Amelogenin Peptide Extract Increases Differentiation and Angiogenic and Local Factor Production and Inhibits Apoptosis in Human Osteoblasts. ACTA ACUST UNITED AC 2013. [DOI: 10.5402/2013/347318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Enamel matrix derivative (EMD), a decellularized porcine extracellular matrix (ECM), is used clinically in periodontal tissue regeneration. Amelogenin, EMD’s principal component, spontaneously assembles into nanospheres in vivo, forming an ECM complex that releases proteolytically cleaved peptides. However, the role of amelogenin or amelogenin peptides in mediating osteoblast response to EMD is not clear. Human MG63 osteoblast-like cells or normal human osteoblasts were treated with recombinant human amelogenin or a 5 kDa tyrosine-rich amelogenin peptide (TRAP) isolated from EMD and the effect on osteogenesis, local factor production, and apoptosis assessed. Treated MG63 cells increased alkaline phosphatase specific activity and levels of osteocalcin, osteoprotegerin, prostaglandin E2, and active/latent TGF-β1, an effect sensitive to the effector and concentration. Primary osteoblasts exhibited similar, but less robust, effects. TRAP-rich 5 kDa peptides yielded more mineralization than rhAmelogenin in osteoblasts in vitro. Both amelogenin and 5 kDa peptides protected MG63s from chelerythrine-induced apoptosis. The data suggest that the 5 kDa TRAP-rich sequence is an active amelogenin peptide that regulates osteoblast differentiation and local factor production and prevents osteoblast apoptosis.
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Affiliation(s)
- Rene Olivares-Navarrete
- School of Engineering, Virginia Commonwealth University, 601 West Main Street, Suite 331, Richmond, VA 23284-3068, USA
| | - Sharon L. Hyzy
- School of Engineering, Virginia Commonwealth University, 601 West Main Street, Suite 331, Richmond, VA 23284-3068, USA
| | - Argelia Almaguer-Flores
- Facultad de Odontologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Coyoacán, 04510 DF, Mexico
| | - Corinna Mauth
- Institut Straumann AG, Nauenstrasse, 4052 Basel, Switzerland
| | | | - Barbara D. Boyan
- School of Engineering, Virginia Commonwealth University, 601 West Main Street, Suite 331, Richmond, VA 23284-3068, USA
| | - Zvi Schwartz
- School of Engineering, Virginia Commonwealth University, 601 West Main Street, Suite 331, Richmond, VA 23284-3068, USA
- Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Enamel defects reflect perinatal exposure to bisphenol A. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 183:108-18. [PMID: 23764278 DOI: 10.1016/j.ajpath.2013.04.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/08/2013] [Accepted: 04/01/2013] [Indexed: 01/21/2023]
Abstract
Endocrine-disrupting chemicals (EDCs), including bisphenol A (BPA), are environmental ubiquitous pollutants and associated with a growing health concern. Anecdotally, molar incisor hypomineralization (MIH) is increasing concurrently with EDC-related conditions, which has led us to investigate the effect of BPA on amelogenesis. Rats were exposed daily to BPA from conception until day 30 or 100. At day 30, BPA-affected enamel exhibited hypomineralization similar to human MIH. Scanning electron microscopy and elemental analysis revealed an abnormal accumulation of organic material in erupted enamel. BPA-affected enamel had an abnormal accumulation of exogenous albumin in the maturation stage. Quantitative real-time PCR, Western blotting, and luciferase reporter assays revealed increased expression of enamelin but decreased expression of kallikrein 4 (protease essential for removing enamel proteins) via transcriptional regulation. Data suggest that BPA exerts its effects on amelogenesis by disrupting normal protein removal from the enamel matrix. Interestingly, in 100-day-old rats, erupting incisor enamel was normal, suggesting amelogenesis is only sensitive to MIH-causing agents during a specific time window during development (as reported for human MIH). The present work documents the first experimental model that replicates MIH and presents BPA as a potential causative agent of MIH. Because human enamel defects are irreversible, MIH may provide an easily accessible marker for reporting early EDC exposure in humans.
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Tamburstuen MV, Snead ML, Reseland JE, Paine ML, Lyngstadaas SP. Ameloblastin upstream region contains structural elements regulating transcriptional activity in a stromal cell line derived from bone marrow. Eur J Oral Sci 2012; 119 Suppl 1:286-92. [PMID: 22243258 DOI: 10.1111/j.1600-0722.2011.00910.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Ameloblastin (AMBN) was originally described as a tooth-specific extracellular matrix protein, but current data have shown that AMBN is present in many different tissues of mesenchymal origin. The identification of regulatory elements in the promoter region of the Ambn gene would assist in identifying potential mesenchymal-specific transcriptional factors. In this study we subcloned a 3,788-bp region upstream (and a 54-bp region downstream) of the mouse Ambn transcriptional start site into a LacZ reporter construct and called this construct 3788-Ambn-lacZ. In silico analysis of the 3,788-bp Ambn promoter region identified 50 potential cis-regulatory elements, 29 of which are known to be functional in cell populations of mesenchymal origin. The reporter construct was activated in transfected bone marrow cells, and the promoter activity was induced in cell cultures following addition of recombinant AMBN, interferon-γ, serotonin, or dexamethasone. We discuss the relative significance of the potential cis-acting gene-regulatory elements of Ambn in relation to bone morphogenesis. Knowledge of Ambn gene-regulatory elements will be of importance when developing strategies for bone repair and replacement in a clinical surgical setting.
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Affiliation(s)
- Margareth V Tamburstuen
- Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo (UiO), Oslo, Norway
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Grandin HM, Gemperli AC, Dard M. Enamel matrix derivative: a review of cellular effects in vitro and a model of molecular arrangement and functioning. TISSUE ENGINEERING PART B-REVIEWS 2011; 18:181-202. [PMID: 22070552 DOI: 10.1089/ten.teb.2011.0365] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Enamel matrix derivative (EMD), the active component of Emdogain®, is a viable option in the treatment of periodontal disease owing to its ability to regenerate lost tissue. It is believed to mimic odontogenesis, though the details of its functioning remain the focus of current research. OBJECTIVE The aim of this article is to review all relevant literature reporting on the composition/characterization of EMD as well as the effects of EMD, and its components amelogenin and ameloblastin, on the behavior of various cell types in vitro. In this way, insight into the underlying mechanism of regeneration will be garnered and utilized to propose a model for the molecular arrangement and functioning of EMD. METHODS A review of in vitro studies of EMD, or components of EMD, was performed using key words "enamel matrix proteins" OR "EMD" OR "Emdogain" OR "amelogenin" OR "ameloblastin" OR "sheath proteins" AND "cells." Results of this analysis, together with current knowledge on the molecular composition of EMD and the structure and regulation of its components, are then used to present a model of EMD functioning. RESULTS Characterization of the molecular composition of EMD confirmed that amelogenin proteins, including their enzymatically cleaved and alternatively spliced fragments, dominate the protein complex (>90%). A small presence of ameloblastin has also been reported. Analysis of the effects of EMD indicated that gene expression, protein production, proliferation, and differentiation of various cell types are affected and often enhanced by EMD, particularly for periodontal ligament and osteoblastic cell types. EMD also stimulated angiogenesis. In contrast, EMD had a cytostatic effect on epithelial cells. Full-length amelogenin elicited similar effects to EMD, though to a lesser extent. Both the leucine-rich amelogenin peptide and the ameloblastin peptides demonstrated osteogenic effects. A model for molecular structure and functioning of EMD involving nanosphere formation, aggregation, and dissolution is presented. CONCLUSIONS EMD elicits a regenerative response in periodontal tissues that is only partly replicated by amelogenin or ameloblastin components. A synergistic effect among the various proteins and with the cells, as well as a temporal effect, may prove important aspects of the EMD response in vivo.
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Tamburstuen MV, Reseland JE, Spahr A, Brookes SJ, Kvalheim G, Slaby I, Snead ML, Lyngstadaas SP. Ameloblastin expression and putative autoregulation in mesenchymal cells suggest a role in early bone formation and repair. Bone 2011; 48:406-13. [PMID: 20854943 PMCID: PMC4469498 DOI: 10.1016/j.bone.2010.09.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Revised: 08/24/2010] [Accepted: 09/07/2010] [Indexed: 10/19/2022]
Abstract
Ameloblastin is mainly known as a dental enamel protein, synthesized and secreted into developing enamel matrix by the enamel-forming ameloblasts. The function of ameloblastin in tooth development remains unclear, but it has been suggested to be involved in processes varying from regulating crystal growth to activity as a growth factor or partaking in cell signaling. Recent studies suggest that some enamel matrix proteins also might have important functions outside enamel formation. In this context ameloblastin has recently been reported to induce dentin and bone repair, as well as being present in the early bone and cartilage extracellular matrices during embryogenesis. However, what cells express ameloblastin in these tissues still remains unclear. Thus, the expression of ameloblastin was examined in cultured primary mesenchymal cells and in vivo during healing of bone defects in a "proof of concept" animal study. Real time RT-PCR analysis revealed human ameloblastin (AMBN) mRNA expression in human mesenchymal stem cells and primary osteoblasts and chondrocytes. Expression of AMBN mRNA was also confirmed in human CD34 positive cells and osteoclasts. Western and dot blot analysis of cell lysates and medium confirmed the expression and secretion of ameloblastin from mesenchymal stem cells, primary human osteoblasts and chondrocytes. Expression of ameloblastin was also detected in newly formed bone in experimental bone defects in adult rats. Together these findings suggest a role for this protein in early bone formation and repair.
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Affiliation(s)
| | - Janne E. Reseland
- Department of Biomaterials, Faculty of Dentistry, University of Oslo (UiO), Oslo, Norway
| | | | - Steven J. Brookes
- Department of Oral Biology, Leeds Dental Institute, University of Leeds, Leeds, UK
| | - Gunnar Kvalheim
- Department of Cellular Therapy, Radiumhospitalet, Oslo University Hospital, Oslo, Norway
| | - Ivan Slaby
- Department of Biomaterials, Faculty of Dentistry, University of Oslo (UiO), Oslo, Norway
| | | | - S. Petter Lyngstadaas
- Department of Biomaterials, Faculty of Dentistry, University of Oslo (UiO), Oslo, Norway
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Toth K, Shao Q, Lorentz R, Laird DW. Decreased levels of Cx43 gap junctions result in ameloblast dysregulation and enamel hypoplasia in Gja1Jrt/+ mice. J Cell Physiol 2010; 223:601-9. [PMID: 20127707 DOI: 10.1002/jcp.22046] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Coordinated differentiation of the ameloblast cell layer is essential to enamel matrix protein deposition and subsequent mineralization. It has been hypothesized that this process is governed by Cx43-based gap junctional intercellular communication as oculodentodigital dysplasia (ODDD) patients harboring autosomal-dominant mutations in Cx43 exhibit enamel defects typically resulting in early adulthood tooth loss. To assess the role of Cx43 in tooth development we employ a mouse model of ODDD that harbors a G60S Cx43 mutant, Gja1(Jrt)/+, and appears to exhibit tooth abnormalities that mimic the human disease. We found that total Cx43 plaques at all stages of ameloblast differentiation, as well as within the supporting cell layers, were greatly reduced in Gja1(Jrt)/+ incisors compared to wild-type littermate controls. To characterize the Gja1(Jrt)/+ mouse tooth phenotype, mice were sacrificed prior to tooth eruption (postnatal day 7), weaning (postnatal day 21), and adulthood (2 months postnatal). A severely disorganized Gja1(Jrt)/+ mouse ameloblast layer and abnormal accumulation of amelogenin were observed at stages when the cells were active in secretion and mineralization. Differences in enamel thickness became more apparent after tooth eruption and incisor exposure to the oral cavity suggesting that enamel integrity is compromised, leading to rapid erosion. Additional analysis of incisors from mutant mice revealed that they were longer with a thicker dentin layer than their wild-type littermates, which may reflect a mechanical stress response to the depleted enamel layer. Together, these data show that reduced levels of Cx43 gap junctions result in ameloblast dysregulation, enamel hypoplasia, and secondary tissue responses.
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Affiliation(s)
- K Toth
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
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Catón J, Tucker AS. Current knowledge of tooth development: patterning and mineralization of the murine dentition. J Anat 2010; 214:502-15. [PMID: 19422427 DOI: 10.1111/j.1469-7580.2008.01014.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The integument forms a number of different types of mineralized element, including dermal denticles, scutes, ganoid scales, elasmoid scales, fin rays and osteoderms found in certain fish, reptiles, amphibians and xenarthran mammals. To this list can be added teeth, which are far more widely represented and studied than any of the other mineralized elements mentioned above, and as such can be thought of as a model mineralized system. In recent years the focus for studies on tooth development has been the mouse, with a wealth of genetic information accrued and the availability of cutting edge techniques. It is the mouse dentition that this review will concentrate on. The development of the tooth will be followed, looking at what controls the shape of the tooth and how signals from the mesenchyme and epithelium interact to lead to formation of a molar or incisor. The number of teeth generated will then be investigated, looking at how tooth germ number can be reduced or increased by apoptosis, fusion of tooth germs, creation of new tooth germs, and the generation of additional teeth from existing tooth germs. The development of mineralized tissue will then be detailed, looking at how the asymmetrical deposition of enamel is controlled in the mouse incisor. The continued importance of epithelial-mesenchymal interactions at these later stages of tooth development will also be discussed. Tooth anomalies and human disorders have been well covered by recent reviews, therefore in this paper we wish to present a classical review of current knowledge of tooth development, fitting together data from a large number of recent research papers to draw general conclusions about tooth development.
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Affiliation(s)
- Javier Catón
- Department of Craniofacial Development and Orthodontics, King's College London, Guy's Hospital, UK
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Vymetal J, Slabý I, Spahr A, Vondrásek J, Lyngstadaas SP. Bioinformatic analysis and molecular modelling of human ameloblastin suggest a two-domain intrinsically unstructured calcium-binding protein. Eur J Oral Sci 2008; 116:124-34. [PMID: 18353005 DOI: 10.1111/j.1600-0722.2008.00526.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ameloblastin (AMBN) was originally believed to be an enamel-specific extracellular matrix glycoprotein secreted by ameloblasts. Recently, AMBN expression was also detected in developing mesenchymal dental hard tissues, in trauma-induced reparative dentin, and during early craniofacial bone formation. The function and structure of AMBN still remain ambiguous, and there are no known proteins with similar primary sequences. We therefore performed a bio-informatic analysis of AMBN to model ab initio the three-dimensional structure of the molecule. The results suggest that AMBN is a two-domain, intrinsically unstructured protein (IUP). The analysis did not reveal any regions with structural similarity to known receptor-ligand systems, and did not identify any higher-order structures similar to functional regions in other known sequences. The AMBN model predicts 11 defined regions exposed on the surface, internalizing the rest of the molecule including a human-specific insert. Molecular dynamics analysis identified one specific and several non-specific calcium-binding regions, mostly at the C-terminal part of the molecule. The model is supported by previous observations that AMBN is a bipolar calcium-binding molecule and hints at a possible role in protein-protein interactions. The model provides information useful for further studies on the function of AMBN.
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Affiliation(s)
- Jirí Vymetal
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam, Prague, Czech Republic
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Iwata T, Yamakoshi Y, Hu JCC, Ishikawa I, Bartlett JD, Krebsbach PH, Simmer JP. Processing of ameloblastin by MMP-20. J Dent Res 2007; 86:153-7. [PMID: 17251515 DOI: 10.1177/154405910708600209] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ameloblastin (AMBN) cleavage products are the most abundant non-amelogenin proteins in the enamel matrix of developing teeth. AMBN N-terminal cleavage products accumulate in the sheath space between enamel rods, while AMBN C-terminal products localize within rods. We tested the hypothesis that MMP-20 is the protease that cleaves AMBN. Glycosylated recombinant porcine AMBN (rpAMBN) was expressed in human kidney 293F cells, and recombinant porcine enamelysin (rpMMP-20) was expressed in bacteria. The purified proteins were incubated together at an enzyme:substrate ratio of 1:100. N-terminal sequencing of AMBN digestion products determined that rpMMP-20 cleaved rpAMBN after Pro(2), Gln(130), Gln(139), Arg(170), and Ala(222). This shows that MMP-20 generates the 23-kDa AMBN starting at Tyr(223), as well as the 17-kDa (Val(1)-Arg(170)) and 15-kDa (Val(1)-Gln(130)) AMBN cleavage products that concentrate in the sheath space during the secretory stage. We conclude that MMP-20 processes ameloblastin in vitro and in vivo.
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Affiliation(s)
- T Iwata
- Department of Biologic and Materials Sciences, Dental Research Lab, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI 48108, USA
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Spahr A, Lyngstadaas SP, Slaby I, Pezeshki G. Ameloblastin expression during craniofacial bone formation in rats. Eur J Oral Sci 2007; 114:504-11. [PMID: 17184233 DOI: 10.1111/j.1600-0722.2006.00403.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Based on previous results showing the expression of ameloblastin (Ambn; amelin) in the formation of mesenchymal dental hard tissues, we investigated its presence during bone development. Immunohistochemistry (IHC), in situ hybridization (ISH), and reverse transcription-polymerase chain reaction (RT-PCR) were used to investigate the expression of ameloblastin protein and mRNA during craniofacial development in rats. Tissue samples were collected on embryonic day 18 and from days 2-28 postnatally. IHC revealed the expression of ameloblastin during bone formation at embryonic and early postnatal stages with different patterns of expression in intramembranous and endochondral ossification. In intramembranous ossification, ameloblastin expression was detected in the superficial layer of the condensed vascularized primitive connective tissue and in the cellular layer covering the surface of the newly formed woven bone. In endochondral ossification, ameloblastin was expressed within the extracellular matrix of the cartilage templates and in the perichondrium. Between days 2 and 28 the expression decreased markedly, concordant with the maturation of the bone, and disappeared after completion of bone remodeling. The results obtained by IHC were confirmed by ISH and RT-PCR, showing the expression of ameloblastin mRNA during craniofacial bone formation. This study indicates the expression of the putative dental protein ameloblastin during craniofacial bone development in rats.
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Affiliation(s)
- Axel Spahr
- Department Of Conservative Dentistry and Periodontology, University of Ulm, Ulm, Germany.
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Brookes SJ, Lyngstadaas SP, Robinson C, Shore RC, Kirkham J. Intracellular nanosphere subunit assembly as revealed by amelogenin molecular cross-linking studies. Eur J Oral Sci 2006; 114 Suppl 1:280-4; discussion 285-6, 382. [PMID: 16674699 DOI: 10.1111/j.1600-0722.2006.00311.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enamel matrix comprises nanospheres predominantly composed of amelogenin. Studies have shown that recombinant amelogenin forms nanospheres similar to those formed in vivo, but it is unclear exactly how nanospheres assemble in vivo. Are amelogenin monomers secreted into the enamel matrix where they then self-assemble to form nanospheres, or does nanosphere assembly actually occur intracellularly? The aim of this study was to attempt to answer this question. Rat enamel organs were treated with the bifunctional cross-linker, dithio bis (succinimidyl propionate) (DSP), which cross-links primary amines lying in close molecular proximity. The key to this technique is the fact that DSP cross-links are later sensitive to reductive cleavage. The cross-linked proteins were first subjected to non-reducing sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) in the first dimension and then to reducing SDS-PAGE in the second dimension (so-called diagonal electrophoresis) followed by western blot probing with anti-amelogenin. The results indicated that intracellular amelogenin monomers are in close neighbor contact, forming complexes comprising up to six individual amelogenin monomers. We suggest that these initial complexes are prefabricated intracellularly before secretion. Once secreted, these prefabricated subunits assemble further to form the mature full-size nanospheres containing hundreds of individual amelogenins characteristic of enamel matrix.
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Affiliation(s)
- Steven J Brookes
- Department of Oral Biology, Leeds Dental Institute, Leeds, UK, and Oral Research Laboratory, Faculty of Dentistry, University of Oslo, Norway.
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20
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Stephanopoulos G, Garefalaki ME, Lyroudia K. Genes and related proteins involved in amelogenesis imperfecta. J Dent Res 2006; 84:1117-26. [PMID: 16304440 DOI: 10.1177/154405910508401206] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Dental enamel formation is a remarkable example of a biomineralization process. The exact mechanisms involved in this process remain partly obscure. Some of the genes encoding specific enamel proteins have been indicated as candidate genes for amelogenesis imperfecta. Mutational analyses within studied families have supported this hypothesis. Mutations in the amelogenin gene (AMELX) cause X-linked amelogenesis imperfecta, while mutations in the enamelin gene (ENAM) cause autosomal-inherited forms of amelogenesis imperfecta. Recent reports involve kallikrein-4 (KLK4), MMP-20, and DLX3 genes in the etiologies of some cases. This paper focuses mainly on the candidate genes involved in amelogenesis imperfecta and the proteins derived from them, and reviews current knowledge on their structure, localization within the tissue, and correlation with the various types of this disorder.
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Affiliation(s)
- G Stephanopoulos
- Diploma in Dental Science, Aristotle University of Thessaloniki, Greece
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21
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Abstract
Dental enamel forms as a progressively thickening extracellular layer by the action of proteins secreted by ameloblasts. The most abundant enamel protein is amelogenin, which is expressed primarily from a gene on the X-chromosome (AMELX). The two most abundant non-amelogenin enamel proteins are ameloblastin and enamelin, which are expressed from the AMBN and ENAM genes, respectively. The human AMBN and ENAM genes are located on chromosome 4q13.2. The major secretory products of the human AMELX, AMBN, and ENAM genes have 175, 421, and 1103 amino acids, respectively, and are all post-translationally modified, secreted, and processed by proteases. Mutations in AMELX have been shown to cause X-linked amelogenesis imperfecta (AI), which accounts for 5% of AI cases. Mutations in ENAM cause a severe form of autosomal-dominant smooth hypoplastic AI that represents 1.5%, and a mild form of autosomal-dominant local hypoplastic AI that accounts for 27% of AI cases in Sweden. The discovery of mutations in the ENAM gene in AI kindreds proved that enamelin is critical for proper dental enamel formation and that it plays a role in human disease. Here we review how enamelin was discovered, what is known about enamelin protein structure, post-translational modifications, processing by proteases, and its potentially important functional properties such as its affinity for hydroxyapatite and influence on crystal growth in vitro. The primary structures of human, porcine, mouse, and rat enamelin are compared, and the human enamelin gene, its structure, chromosomal localization, temporal and spatial patterns of expression, and its role in the etiology of amelogenesis imperfecta are discussed.
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Affiliation(s)
- J C-C Hu
- Department of Orthodontics and Pediatric Dentistry, University of Michigan, School of Dentistry, 1011 North University, Ann Arbor, MI 48109-1078, USA.
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Brookes SJ, Lyngstadaas SP, Robinson C, Shore RC, Wood SR, Kirkham J. Enamelin compartmentalization in developing porcine enamel. Connect Tissue Res 2003; 43:477-81. [PMID: 12489201 DOI: 10.1080/03008200290000862] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The tissue compartmentalization of enamelin-processing products has been investigated in developing pig enamel using a sequential extraction procedure. Only trace amounts of enamelin-processing products were detected in simulated enamel fluid extracts, suggesting that enamelins are not solubilized in the matrix to any great extent. Subsequent phosphate buffer extraction desorbed and extracted several enamelin-processing products that were presumably bound to the mineral phase. A 35-kD processing product dominated the phosphate extract, suggesting that enamelin processing leads to an accumulation of this mineral-bound molecule. Dissociative extraction with urea subsequently extracted the remainder of the enamelin-processing products present. This material was presumably present in the tissue in an aggregated insoluble state. Several enamelin-processing products were only extracted by specific extraction procedures, suggesting that different enamelin-processing products are differentially compartmentalized. This may indicate that specific enamelin-processing products have different functions. In contrast to amelogenins, which are processed in the deeper tissue to generate products having a low affinity for the mineral, enamelin processing appears to produce products (those enamelins desorbed by phosphate buffer) that have a high affinity for the mineral. These products, appearing in the deeper enamel layers, may serve to influence crystal growth kinetics in the absence of any mineral-binding amelogenins.
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Affiliation(s)
- S J Brookes
- Division of Oral Biology, Leeds Dental Institute, Leeds LS2 9LU, UK.
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Abstract
Enamel proteins are proteins synthesized by ameloblast cells. These proteins are secreted into the enamel extracellular matrix where they nucleate and regulate the growth of hydroxyapatite crystals to form the mineralized enamel covering the crown of the teeth. Although the exact role of these proteins in enamel mineralization is just beginning to be elucidated, new studies suggest that these proteins might have functions outside enamel formation. Furthermore, extracts of enamel proteins are currently being used to regenerate periodontal tissues destroyed by periodontal disease and new studies suggest that they might have chondrogenic and osteogenic properties. These new functions of enamel proteins will be the focus of this review.
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Affiliation(s)
- M Zeichner-David
- University of Southern California School of Dentistry, Center for Craniofacial Molecular Biology, 2250 Alcazar Street, CSA 106, Los Angeles, CA 90033, USA.
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