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Lee DJ, Kim P, Kim HY, Park J, Lee SJ, An H, Heo JS, Lee MJ, Ohshima H, Mizuno S, Takahashi S, Jung HS, Kim SJ. MAST4 regulates stem cell maintenance with DLX3 for epithelial development and amelogenesis. Exp Mol Med 2024; 56:1606-1619. [PMID: 38945953 PMCID: PMC11297042 DOI: 10.1038/s12276-024-01264-5] [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: 04/26/2023] [Revised: 01/29/2024] [Accepted: 03/19/2024] [Indexed: 07/02/2024] Open
Abstract
The asymmetric division of stem cells permits the maintenance of the cell population and differentiation for harmonious progress. Developing mouse incisors allows inspection of the role of the stem cell niche to provide specific insights into essential developmental phases. Microtubule-associated serine/threonine kinase family member 4 (Mast4) knockout (KO) mice showed abnormal incisor development with low hardness, as the size of the apical bud was decreased and preameloblasts were shifted to the apical side, resulting in amelogenesis imperfecta. In addition, Mast4 KO incisors showed abnormal enamel maturation, and stem cell maintenance was inhibited as amelogenesis was accelerated with Wnt signal downregulation. Distal-Less Homeobox 3 (DLX3), a critical factor in tooth amelogenesis, is considered to be responsible for the development of amelogenesis imperfecta in humans. MAST4 directly binds to DLX3 and induces phosphorylation at three residues within the nuclear localization site (NLS) that promotes the nuclear translocation of DLX3. MAST4-mediated phosphorylation of DLX3 ultimately controls the transcription of DLX3 target genes, which are carbonic anhydrase and ion transporter genes involved in the pH regulation process during ameloblast maturation. Taken together, our data reveal a novel role for MAST4 as a critical regulator of the entire amelogenesis process through its control of Wnt signaling and DLX3 transcriptional activity.
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Affiliation(s)
- Dong-Joon Lee
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Taste Research Center, Oral Science Research Center, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, 03722, Korea
- Department of Oral Histology, Dankook University College of Dentistry, Cheonan, 31116, Korea
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Korea
| | - Pyunggang Kim
- GILO Institute, GILO Foundation, Seoul, 06668, Korea
| | - Hyun-Yi Kim
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Taste Research Center, Oral Science Research Center, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, 03722, Korea
- NGeneS Inc., Ansan-si, Gyeonggi-do, 15495, Korea
| | - Jinah Park
- GILO Institute, GILO Foundation, Seoul, 06668, Korea
| | - Seung-Jun Lee
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Taste Research Center, Oral Science Research Center, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, 03722, Korea
| | - Haein An
- GILO Institute, GILO Foundation, Seoul, 06668, Korea
| | - Jin Sun Heo
- GILO Institute, GILO Foundation, Seoul, 06668, Korea
| | - Min-Jung Lee
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Taste Research Center, Oral Science Research Center, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, 03722, Korea
| | - 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, 951-8514, Japan
| | - Seiya Mizuno
- Laboratory Animal Resource Center, University of Tsukuba, Tsukuba, Ibaraki, 305-8575, Japan
| | - Satoru Takahashi
- Laboratory Animal Resource Center, University of Tsukuba, Tsukuba, Ibaraki, 305-8575, Japan
| | - Han-Sung Jung
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Taste Research Center, Oral Science Research Center, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, 03722, Korea.
| | - Seong-Jin Kim
- GILO Institute, GILO Foundation, Seoul, 06668, Korea.
- Medpacto Inc., Seoul, 06668, Korea.
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Shin M, Matsushima A, Nagao JI, Tanaka Y, Harada H, Okabe K, Bartlett JD. Mobility gene expression differences among wild-type, Mmp20 null and Mmp20 over-expresser mice plus visualization of 3D mouse ameloblast directional movement. Sci Rep 2023; 13:18829. [PMID: 37914726 PMCID: PMC10620228 DOI: 10.1038/s41598-023-44627-0] [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: 05/23/2023] [Accepted: 10/10/2023] [Indexed: 11/03/2023] Open
Abstract
Enamel forming ameloblasts move away from the dentino-enamel junction and also move relative to each other to establish enamel shape during the secretory stage of enamel development. Matrix metalloproteinase-20 (MMP20) is a tooth specific proteinase essential for proper enamel formation. We previously reported that MMP20 cleaves cadherins and may regulate ameloblast movement. Here, we used an Amelx promoter driven tdTomato reporter to label mouse ameloblasts. With these transgenic mice, we assessed ameloblast mobility group dynamics and gene expression. Three-dimensional imaging of mouse ameloblasts were observed in hemi-mandibles by using a tissue clearing technique. The three-dimensional ameloblast layer in Tg(Amelx-Mmp20) mice that overexpress MMP20 was uneven and the ameloblasts migrated away from this layer. Mouse ameloblast movement toward incisal tips was monitored by ex vivo time-lapse imaging. Gene expression related to cell migration and adhesion was analyzed in ameloblasts from wild-type mice, Mmp20-/- mice with no functional MMP20 and from Tg(Amelx-Mmp20) overexpressing mice. Gene expression was altered in Mmp20-/- and Tg(Amelx-Mmp20) mice compared to wild type. Among the genes assessed, those encoding laminins and a gap junction protein were upregulated in Mmp20-/- mice. New techniques and findings described in this study may lead to an improved understanding of ameloblast movement during enamel formation.
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Affiliation(s)
- Masashi Shin
- Section of Cellular Physiology, Department of Physiological Science and Molecular Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan.
- Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, Japan.
| | - Aya Matsushima
- Section of Cellular Physiology, Department of Physiological Science and Molecular Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Jun-Ichi Nagao
- Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, Japan
- Section of Infection Biology, Department of Functional Bioscience, Fukuoka Dental College, Fukuoka, Japan
| | - Yoshihiko Tanaka
- Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, Japan
- Section of Infection Biology, Department of Functional Bioscience, Fukuoka Dental College, Fukuoka, Japan
| | - Hidemitsu Harada
- Divison of Developmental Biology and Regenerative Medicine, Department of Anatomy, Iwate Medical University, Iwate, Japan
| | - Koji Okabe
- Section of Cellular Physiology, Department of Physiological Science and Molecular Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - John D Bartlett
- Division of Biosciences, College of Dentistry, Ohio State University, Columbus, OH, USA
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Nasseri S, Parsa S, Vahabzadeh Z, Baban B, Khademerfan MB, Nikkhoo B, Rastegar Khosravi M, Bahrami S, Fathi F. CRISPR/Cas9-Induced Fam83h Knock-out Leads to Impaired Wnt/β-Catenin Pathway and Altered Expression of Tooth Mineralization Genes in Mice. IRANIAN JOURNAL OF BIOTECHNOLOGY 2023; 21:e3673. [PMID: 38269199 PMCID: PMC10804060 DOI: 10.30498/ijb.2023.391902.3673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/19/2023] [Indexed: 01/26/2024]
Abstract
Background Dental enamel formation is a complex process that is regulated by various genes. One such gene, Family With Sequence Similarity 83 Member H (Fam83h), has been identified as an essential factor for dental enamel formation. Additionally, Fam83h has been found to be potentially linked to the Wnt/β-catenin pathway. Objectives This study aimed to investigate the effects of the Fam83h knockout gene on mineralization and formation of teeth, along with mediators of the Wnt/β-catenin pathway as a development aspect in mice. Materials and Methods To confirm the Fam83h-KnockOut mice, both Sanger sequencing and Western blot methods were used. then used qPCR to measure the expression levels of genes related to tooth mineralization and formation of dental root, including Fam20a, Dspp, Dmp1, Enam, Ambn, Sppl2a, Mmp20, and Wnt/β-catenin pathway mediators, in both the Fam83h-Knockout and wild-type mice at 5, 11 and 18 days of age. also the expression level of Fgf10 and mediators of the Wnt/β-catenin pathway was measured in the skin of both Knockout and wild-type mice using qPCR. A histological assessment was then performed to further investigate the results. Results A significant reduction in the expression levels of Ambn, Mmp20, Dspp, and Fgf10 in the dental root of Fam83h-Knockout mice compared to their wild-type counterparts was demonstrated by our results, indicating potential disruptions in tooth development. Significant down-regulation of CK1a, CK1e, and β-catenin in the dental root of Fam83h-Knockout mice was associated with a reduction in mineralization and formation-related gene. Additionally, the skin analysis of Fam83h-Knockout mice revealed reduced levels of Fgf10, CK1a, CK1e, and β-catenin. Further histological assessment confirmed that the concurrent reduction of Fgf10 expression level and Wnt/β-catenin genes were associated with alterations in hair follicle maturation. Conclusions The concurrent reduction in the expression level of both Wnt/β-catenin mediators and mineralization-related genes, resulting in the disruption of dental mineralization and formation, was caused by the deficiency of Fam83h. Our findings suggest a cumulative effect and multi-factorial interplay between Fam83h, Wnt/Β-Catenin signaling, and dental mineralization-related genes subsequently, during the dental formation process.
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Affiliation(s)
- Sherko Nasseri
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
- Department of Molecular Medicine and Medical biotechnology, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Sara Parsa
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Zakaria Vahabzadeh
- Liver and Digestive Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
- Department of Biochemistry, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Babak Baban
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, Georgia
| | - Mohammad Bagher Khademerfan
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
- Department of Molecular Medicine and Medical biotechnology, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Bahram Nikkhoo
- Department of Pathology, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Mohammad Rastegar Khosravi
- Department of Endodontics, Faculty of Dentistry, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Saman Bahrami
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Fardin Fathi
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
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Hermans F, Hemeryck L, Lambrichts I, Bronckaers A, Vankelecom H. Intertwined Signaling Pathways Governing Tooth Development: A Give-and-Take Between Canonical Wnt and Shh. Front Cell Dev Biol 2021; 9:758203. [PMID: 34778267 PMCID: PMC8586510 DOI: 10.3389/fcell.2021.758203] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/11/2021] [Indexed: 11/13/2022] Open
Abstract
Teeth play essential roles in life. Their development relies on reciprocal interactions between the ectoderm-derived dental epithelium and the underlying neural crest-originated mesenchyme. This odontogenic process serves as a prototype model for the development of ectodermal appendages. In the mouse, developing teeth go through distinct morphological phases that are tightly controlled by epithelial signaling centers. Crucial molecular regulators of odontogenesis include the evolutionarily conserved Wnt, BMP, FGF and sonic hedgehog (Shh) pathways. These signaling modules do not act on their own, but are closely intertwined during tooth development, thereby outlining the path to be taken by specific cell populations including the resident dental stem cells. Recently, pivotal Wnt-Shh interaction and feedback loops have been uncovered during odontogenesis, showing conservation in other developing ectodermal appendages. This review provides an integrated overview of the interplay between canonical Wnt and Shh throughout mouse tooth formation stages, extending from the initiation of dental placode to the fully formed adult tooth.
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Affiliation(s)
- Florian Hermans
- Laboratory of Tissue Plasticity in Health and Disease, Cluster of Stem Cell and Developmental Biology, Department of Development and Regeneration, Leuven Stem Cell Institute, KU Leuven (University of Leuven), Leuven, Belgium.,Biomedical Research Institute (BIOMED), Department of Cardio and Organ Systems, UHasselt-Hasselt University, Diepenbeek, Belgium
| | - Lara Hemeryck
- Laboratory of Tissue Plasticity in Health and Disease, Cluster of Stem Cell and Developmental Biology, Department of Development and Regeneration, Leuven Stem Cell Institute, KU Leuven (University of Leuven), Leuven, Belgium
| | - Ivo Lambrichts
- Biomedical Research Institute (BIOMED), Department of Cardio and Organ Systems, UHasselt-Hasselt University, Diepenbeek, Belgium
| | - Annelies Bronckaers
- Biomedical Research Institute (BIOMED), Department of Cardio and Organ Systems, UHasselt-Hasselt University, Diepenbeek, Belgium
| | - Hugo Vankelecom
- Laboratory of Tissue Plasticity in Health and Disease, Cluster of Stem Cell and Developmental Biology, Department of Development and Regeneration, Leuven Stem Cell Institute, KU Leuven (University of Leuven), Leuven, Belgium
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ADAM10 is Expressed by Ameloblasts, Cleaves the RELT TNF Receptor Extracellular Domain and Facilitates Enamel Development. Sci Rep 2019; 9:14086. [PMID: 31575895 PMCID: PMC6773779 DOI: 10.1038/s41598-019-50277-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/04/2019] [Indexed: 12/13/2022] Open
Abstract
MMP20 cleaves cadherins and may facilitate cell movement, however MMP20 is not known to cleave tight junction or desmosome proteins. Ameloblasts had not previously been screened for membrane anchored proteases that could contribute to cell movement. Here we performed a PCR screen for proteolyticlly active A Disintegrin And Metalloproteinase (ADAM) family members. These proteinases are termed sheddases because they have a transmembrane domain and their catalytic domain on the cell surface can function to release anchored proteins. Significantly, ADAMs can be targeted to specific substrates on the cell membrane through their interaction with tetraspanins. Six ADAMs (ADAM8, 9, 10, 15, 17, 19) were expressed in mouse enamel organs. We show that Adam10 expression begins in the apical loop, continues through the secretory stage and abruptly ends at the transition stage when ameloblast migration ceases. ADAM10 cleaves cadherins and tight junction plus desmosome proteins and is well characterized for its role in cell movement. ADAM10 facilitated LS8 cell migration/invasion through a Matrigel coated membrane and we demonstrate that ADAM10, but not ADAM17 cleaves the RELT extracellular domain. This striking result is significant because RELT mutations cause amelogenesis imperfecta (AI) and this directly links ADAM10 to an important role in enamel development.
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Lu X, Yang J, Zhao S, Liu S. Advances of Wnt signalling pathway in dental development and potential clinical application. Organogenesis 2019; 15:101-110. [PMID: 31482738 DOI: 10.1080/15476278.2019.1656996] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Wnt signalling pathway is widely studied in many processes of biological development, like embryogenesis, tissue homeostasis and wound repair. It is universally known that Wnt signalling pathway plays an important role in tooth development. Here, we summarized the function of Wnt signalling pathway during tooth initiation, crown morphogenesis, root formation, and discussed the therapeutic potential of Wnt modulators.
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Affiliation(s)
- Xi Lu
- Department of Stomatology, Huashan Hospital, Fudan University , Shanghai , P. R. China
| | - Jun Yang
- Department of Stomatology, Huashan Hospital, Fudan University , Shanghai , P. R. China
| | - Shouliang Zhao
- Department of Stomatology, Huashan Hospital, Fudan University , Shanghai , P. R. China
| | - Shangfeng Liu
- Department of Stomatology, Huashan Hospital, Fudan University , Shanghai , P. R. China
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Vieira AR, Manton DJ. On the Variable Clinical Presentation of Molar-Incisor Hypomineralization. Caries Res 2019; 53:482-488. [PMID: 30943522 DOI: 10.1159/000496542] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/15/2018] [Indexed: 11/19/2022] Open
Abstract
Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Original reports on the etiology of the condition and possible risk factors were inconclusive, and we refuted the original suggestion that MIH is an idiopathic condition and suggested that MIH has complex inheritance and is due to the interaction of more than one gene and the environment. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. Later we expanded this work to include genes related to the immune response. In this report, we provide a rationale to explain the variation seen in the clinical presentation of MIH, which can affect just one molar out of the four or just a portion of a particular molar.
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Affiliation(s)
- Alexandre Rezende Vieira
- Department of Oral Biology, University of Pittsburgh School of Dental Medicine, Pittsburgh, Pennsylvania, USA,
| | - David J Manton
- Melbourne Dental School, University of Melbourne, Melbourne, Victoria, Australia
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Buchko GW, Jayasinha Arachchige R, Tao J, Tarasevich BJ, Shaw WJ. Identification of major matrix metalloproteinase-20 proteolytic processing products of murine amelogenin and tyrosine-rich amelogenin peptide using a nuclear magnetic resonance spectroscopy based method. Arch Oral Biol 2018; 93:187-194. [PMID: 29960917 DOI: 10.1016/j.archoralbio.2018.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 01/14/2023]
Abstract
OBJECTIVE The aim of this study was to identify major matrix metalloproteinase-20 (MMP20) proteolytic processing products of amelogenin over time and determine if the tyrosine-rich amelogenin peptide (TRAP) was a substrate of MMP20. DESIGN Recombinant15N-labeled murine amelogenin and 13C,15N-labeled TRAP were incubated with MMP20 under conditions where amelogenin self-assembles into nanospheres. Digestion products were fractionated by reverse-phase high-performance liquid chromatography at various time points. Product identification took advantage of the intrinsic disorder property of amelogenin that results in little change to its fingerprint 1H-15N heteronuclear single-quantum coherence nuclear magnetic resonance spectrum in 2% acetic acid upon removing parts of the protein, allowing cleavage site identification by observing which amide cross peaks disappear. RESULTS The primary product in five out of the six major reverse-phase high-performance liquid chromatography bands generated after a 24 h incubation of murine amelogenin with MMP20 were: S55-L163, P2-L147, P2-E162, P2-A167, and P2-R176. After 72 h these products were replaced with five major reverse-phase high-performance liquid chromatography bands containing: L46-A170, P2-S152, P2-F151, P2-W45, and short N-terminal peptides. TRAP was completely digested by MMP20 into multiple small peptides with the initial primary site of cleavage between S16 and Y17. CONCLUSIONS Identification of the major MMP20 proteolytic products of amelogenin confirm a dynamic process, with sites towards the C-terminus more rapidly attacked than sites near the N-terminus. This observation is consistent with nanosphere models where the C-terminus is exposed and the N-terminus more protected. One previously reported end-product of the MMP20 proteolytic processing of amelogenin, TRAP, is shown to be an in vitro substrate for MMP20.
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Affiliation(s)
- Garry W Buchko
- Pacific Northwest National Laboratory, Richland, WA 99352, USA; School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA.
| | | | - Jinhui Tao
- Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| | | | - Wendy J Shaw
- Pacific Northwest National Laboratory, Richland, WA 99352, USA.
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Shin M, Chavez MB, Ikeda A, Foster BL, Bartlett JD. MMP20 Overexpression Disrupts Molar Ameloblast Polarity and Migration. J Dent Res 2018; 97:820-827. [PMID: 29481294 DOI: 10.1177/0022034518758657] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ameloblasts responsible for enamel formation express matrix metalloproteinase 20 (MMP20), an enzyme that cleaves enamel matrix proteins, including amelogenin (AMELX) and ameloblastin (AMBN). Previously, we showed that continuously erupting incisors from transgenic mice overexpressing active MMP20 had a massive cell infiltrate present within their enamel space, leading to enamel mineralization defects. However, effects of MMP20 overexpression on mouse molars were not analyzed, although these teeth more accurately represent human odontogenesis. Therefore, MMP20-overexpressing mice ( Mmp20+/+Tg+) were assessed by multiscale analyses, combining several approaches from high-resolution micro-computed tomography to enamel organ immunoblots. During the secretory stage at postnatal day 6 (P6), Mmp20+/+Tg+ mice had a discontinuous ameloblast layer and, unlike incisors, molar P12 maturation stage ameloblasts abnormally migrated away from the enamel layer into the stratum intermedium/stellate reticulum. TOPflash assays performed in vitro demonstrated that MMP20 expression promoted β-catenin nuclear localization and that MMP20 expression promoted invasion through Matrigel-coated filters. However, for both assays, significant differences were eliminated in the presence of the β-catenin inhibitor ICG-001. This suggests that MMP20 activity promotes cell migration via the Wnt pathway. In vivo, the unique molar migration of amelogenin-expressing ameloblasts was associated with abnormal deposition of ectopic calcified nodules surrounding the adherent enamel layer. Enamel content was assessed just prior to eruption at P15. Compared to wild-type, Mmp20+/+Tg+ molars exhibited significant reductions in enamel thickness (70%), volume (60%), and mineral density (40%), and MMP20 overexpression resulted in premature cleavage of AMBN, which likely contributed to the severe defects in enamel mineralization. In addition, Mmp20+/+Tg+ mouse molar enamel organs had increased levels of inactive p-cofilin, a protein that regulates cell polarity. These data demonstrate that increased MMP20 activity in molars causes premature degradation of ameloblastin and inactivation of cofilin, which may contribute to pathological Wnt-mediated cell migration away from the enamel layer.
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Affiliation(s)
- M Shin
- 1 Fukuoka Dental College, Sawara-ku, Fukuoka, Japan
| | - M B Chavez
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - A Ikeda
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - B L Foster
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - J D Bartlett
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
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