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Saxena G, Koli K, de la Garza J, Ogbureke K. Matrix Metalloproteinase 20–Dentin Sialophosphoprotein Interaction in Oral Cancer. J Dent Res 2015; 94:584-93. [DOI: 10.1177/0022034515570156] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Matrix metalloproteinase 20 (MMP-20), widely regarded as tooth specific, participates with MMP-2 in processing dentin sialophosphoprotein (DSPP) into dentin sialoprotein, dentin phosphoprotein, and dentin glycoprotein. In biochemical system, MMP-2, MMP-3, and MMP-9 bind with high affinity to, and are activated by, specific small integrin-binding ligand N-linked glycoproteins (SIBLINGs): bone sialoprotein, osteopontin, and dentin matrix protein 1, respectively. Subsequent reports documented possible biological relevance of SIBLING-MMP interaction in vivo by showing that SIBLINGs are always coexpressed with their MMP partners. However, the cognate MMPs for 2 other SIBLINGs—DSPP and matrix extracellular phosphogylcoprotein—are yet to be identified. Our goal was to investigate MMP-20 expression and to explore preliminary evidence of its interaction with DSPP in oral squamous cell carcinomas (OSCCs). Immunohistochemistry analysis of sections from 21 cases of archived human OSCC tissues showed immunoreactivity for MMP-20 in 18 (86%) and coexpression with DSPP in all 15 cases (71%) positive for DSPP. Similarly, 28 (93%) of 30 cases of oral epithelial dysplasia were positive for MMP-20. Western blot and quantitative real-time polymerase chain reaction analysis on OSCC cell lines showed upregulation of MMP-20 protein and mRNA, respectively, while immunofluorescence showed coexpression of MMP-20 and DSPP. Colocalization and potential interaction of MMP-20 with dentin sialoprotein was confirmed by coimmunoprecipitation and mass spectrometry analysis of immunoprecipitation product from OSCC cell lysate, and in situ proximity ligation assays. Significantly, results of chromatin immunoprecipation revealed a 9-fold enrichment of DSPP at MMP-20 promoter–proximal elements. Our data provide evidence that MMP-20 has a wider tissue distribution than previously acknowledged. MMP-20–DSPP specific interaction, excluding other MMP-20–SIBLING pairings, identifies MMP-20 as DSPP cognate MMP. Furthermore, the strong DSPP enrichment at the MMP-20 promoter suggests a regulatory role in MMP-20 transcription. These novel findings provide the foundation to explore the mechanisms and significance of DSPP-MMP-20 interaction in oral carcinogenesis.
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Affiliation(s)
- G. Saxena
- Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, TX, USA
| | - K. Koli
- Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, TX, USA
| | - J. de la Garza
- Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, TX, USA
| | - K.U.E. Ogbureke
- Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, TX, USA
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Abstract
In this chapter the basic premises, the recent findings and the future challenges in the use of amelogenin for enamel tissue engineering are being discoursed on. Results emerging from the experiments performed to assess the fundamental physicochemical mechanisms of the interaction of amelogenin, the main protein of the enamel matrix, and the growing crystals of apatite, are mentioned, alongside a moderately comprehensive literature review of the subject at hand. The clinical importance of understanding this protein/mineral interaction at the nanoscale are highlighted as well as the potential for tooth enamel to act as an excellent model system for studying some of the essential aspects of biomineralization processes in general. The dominant paradigm stating that amelogenin directs the uniaxial growth of apatite crystals in enamel by slowing down the growth of (hk0) faces on which it adheres is being questioned based on the results demonstrating the ability of amelogenin to promote the nucleation and crystal growth of apatite under constant titration conditions designed to mimic those present in the developing enamel matrix. The role of numerous minor components of the enamel matrix is being highlighted as essential and impossible to compensate for by utilizing its more abundant ingredients only. It is concluded that the three major aspects of amelogenesis outlined hereby--(1) the assembly of amelogenin and other enamel matrix proteins, (2) the proteolytic activity, and (3) crystallization--need to be in precise synergy with each other in order for the grounds for the proper imitation of amelogenesis in the lab to be created.
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Affiliation(s)
- Vuk Uskoković
- Advanced Materials and Nanobiotechnology Laboratory, Department of Bioengineering, University of Illinois, Chicago, IL, USA.
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Khaddam M, Huet E, Vallée B, Bensidhoum M, Le Denmat D, Filatova A, Jimenez-Rojo L, Ribes S, Lorenz G, Morawietz M, Rochefort GY, Kiesow A, Mitsiadis TA, Poliard A, Petzold M, Gabison EE, Menashi S, Chaussain C. EMMPRIN/CD147 deficiency disturbs ameloblast-odontoblast cross-talk and delays enamel mineralization. Bone 2014; 66:256-66. [PMID: 24970041 DOI: 10.1016/j.bone.2014.06.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 06/10/2014] [Accepted: 06/17/2014] [Indexed: 11/20/2022]
Abstract
Tooth development is regulated by a series of reciprocal inductive signaling between the dental epithelium and mesenchyme, which culminates with the formation of dentin and enamel. EMMPRIN/CD147 is an Extracellular Matrix MetalloPRoteinase (MMP) INducer that mediates epithelial-mesenchymal interactions in cancer and other pathological processes and is expressed in developing teeth. Here we used EMMPRIN knockout (KO) mice to determine the functional role of EMMPRIN on dental tissue formation. We report a delay in enamel deposition and formation that is clearly distinguishable in the growing incisor and associated with a significant reduction of MMP-3 and MMP-20 expression in tooth germs of KO mice. Insufficient basement membrane degradation is evidenced by a persistent laminin immunostaining, resulting in a delay of both odontoblast and ameloblast differentiation. Consequently, enamel volume and thickness are decreased in adult mutant teeth but enamel maturation and tooth morphology are normal, as shown by micro-computed tomographic (micro-CT), nanoindentation, and scanning electron microscope analyses. In addition, the dentino-enamel junction appears as a rough calcified layer of approximately 10±5μm thick (mean±SD) in both molars and growing incisors of KO adult mice. These results indicate that EMMPRIN is involved in the epithelial-mesenchymal cross-talk during tooth development by regulating the expression of MMPs. The mild tooth phenotype observed in EMMPRIN KO mice suggests that the direct effect of EMMPRIN may be limited to a short time window, comprised between basement membrane degradation allowing direct cell contact and calcified matrix deposition.
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Affiliation(s)
- Mayssam Khaddam
- EA 2496, Pathologies, Imaging, and Biotherapies of the Tooth, Dental School Université Paris Descartes Sorbonne Paris Cité, France
| | - Eric Huet
- Laboratoire CRRET, Université Paris-Est, CNRS, Créteil, France
| | - Benoît Vallée
- Laboratoire CRRET, Université Paris-Est, CNRS, Créteil, France
| | - Morad Bensidhoum
- Laboratoire de Bioingénierie et Biomécanique Ostéo-Articulaire UMR CNRS 7052, Faculté de médecine Lariboisière St. Louis Université Paris 7 Sorbonne Paris Cité, France
| | - Dominique Le Denmat
- EA 2496, Pathologies, Imaging, and Biotherapies of the Tooth, Dental School Université Paris Descartes Sorbonne Paris Cité, France
| | - Anna Filatova
- Department of Orofacial Development and Regeneration, Institute of Oral Biology, Center of Dental Medicine, Faculty of Medicine, University of Zurich, Switzerland
| | - Lucia Jimenez-Rojo
- Department of Orofacial Development and Regeneration, Institute of Oral Biology, Center of Dental Medicine, Faculty of Medicine, University of Zurich, Switzerland
| | - Sandy Ribes
- EA 2496, Pathologies, Imaging, and Biotherapies of the Tooth, Dental School Université Paris Descartes Sorbonne Paris Cité, France
| | - Georg Lorenz
- Fraunhofer Institute for Mechanics of Materials IWM, Walter-Hülse-Str. Halle, Saale, Germany
| | - Maria Morawietz
- Fraunhofer Institute for Mechanics of Materials IWM, Walter-Hülse-Str. Halle, Saale, Germany
| | - Gael Y Rochefort
- EA 2496, Pathologies, Imaging, and Biotherapies of the Tooth, Dental School Université Paris Descartes Sorbonne Paris Cité, France
| | - Andreas Kiesow
- Fraunhofer Institute for Mechanics of Materials IWM, Walter-Hülse-Str. Halle, Saale, Germany
| | - Thimios A Mitsiadis
- Department of Orofacial Development and Regeneration, Institute of Oral Biology, Center of Dental Medicine, Faculty of Medicine, University of Zurich, Switzerland
| | - Anne Poliard
- EA 2496, Pathologies, Imaging, and Biotherapies of the Tooth, Dental School Université Paris Descartes Sorbonne Paris Cité, France
| | - Matthias Petzold
- Fraunhofer Institute for Mechanics of Materials IWM, Walter-Hülse-Str. Halle, Saale, Germany
| | - Eric E Gabison
- Fondation ophtalmologique A de Rothschild, Université Paris Diderot, PRES Sorbonne Paris Cité, France
| | - Suzanne Menashi
- Laboratoire CRRET, Université Paris-Est, CNRS, Créteil, France
| | - Catherine Chaussain
- EA 2496, Pathologies, Imaging, and Biotherapies of the Tooth, Dental School Université Paris Descartes Sorbonne Paris Cité, France; AP-HP, Odontology Department, Groupement Hospitalier Nord Val de Seine (Bretonneau), France
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Fluorosed mouse ameloblasts have increased SATB1 retention and Gαq activity. PLoS One 2014; 9:e103994. [PMID: 25090413 PMCID: PMC4121220 DOI: 10.1371/journal.pone.0103994] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 07/06/2014] [Indexed: 02/05/2023] Open
Abstract
Dental fluorosis is characterized by subsurface hypomineralization and increased porosity of enamel, associated with a delay in the removal of enamel matrix proteins. To investigate the effects of fluoride on ameloblasts, A/J mice were given 50 ppm sodium fluoride in drinking water for four weeks, resulting serum fluoride levels of 4.5 µM, a four-fold increase over control mice with no fluoride added to drinking water. MicroCT analyses showed delayed and incomplete mineralization of fluorosed incisor enamel as compared to control enamel. A microarray analysis of secretory and maturation stage ameloblasts microdissected from control and fluorosed mouse incisors showed that genes clustered with Mmp20 appeared to be less downregulated in maturation stage ameloblasts of fluorosed incisors as compared to control maturation ameloblasts. One of these Mmp20 co-regulated genes was the global chromatin organizer, special AT-rich sequence-binding protein-1 (SATB1). Immunohistochemical analysis showed increased SATB1 protein present in fluorosed ameloblasts compared to controls. In vitro, exposure of human ameloblast-lineage cells to micromolar levels of both NaF and AlF3 led to a significantly increase in SATB1 protein content, but not levels of Satb1 mRNA, suggesting a fluoride-induced mechanism protecting SABT1 from degradation. Consistent with this possibility, we used immunohistochemistry and Western blot to show that fluoride exposed ameloblasts had increased phosphorylated PKCα both in vivo and in vitro. This kinase is known to phosphorylate SATB1, and phosphorylation is known to protect SATB1 from degradation by caspase-6. In addition, production of cellular diacylglycerol (DAG) was significantly increased in fluorosed ameloblasts, suggesting that the increased phosphorylation of SATB1 may be related to an effect of fluoride to enhance Gαq activity of secretory ameloblasts.
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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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56
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Zhu L, Liu H, Witkowska HE, Huang Y, Tanimoto K, Li W. Preferential and selective degradation and removal of amelogenin adsorbed on hydroxyapatites by MMP20 and KLK4 in vitro. Front Physiol 2014; 5:268. [PMID: 25104939 PMCID: PMC4109566 DOI: 10.3389/fphys.2014.00268] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 06/26/2014] [Indexed: 11/23/2022] Open
Abstract
The hardest tooth enamel tissue develops from a soft layer of protein-rich matrix, predominated by amelogenin that is secreted by epithelial ameloblasts in the secretory stage of tooth enamel development. During enamel formation, a well-controlled progressive removal of matrix proteins by resident proteases, Matrix metalloproteinase 20 (MMP20), and kallikrein 4 (KLK4), will provide space for the apatite crystals to grow. To better understand the role of amelogenin degradation in enamel biomineralization, the present study was conducted to investigate how the adsorption of amelogenin to hydroxyapatite (HAP) crystals affects its degradation by enamel proteinases, MMP20 and KLK4. Equal quantities of amelogenins confirmed by protein assays before digestions, either adsorbed to HAP or in solution, were incubated with MMP20 or KLK4. The digested samples collected at different time points were analyzed by spectrophotometry, SDS-PAGE, high performance liquid chromatography (HPLC), and LC-MALDI MS/MS. We found that majority of amelogenin adsorbed on HAP was released into the surrounding solution by enzymatic processing (88% for MMP20 and 98% for KLK4). The results show that as compared with amelogenin in solution, the HAP-bound amelogenin was hydrolyzed by both MMP20 and KLK4 at significantly higher rates. Using LC-MALDI MS/MS, more accessible cleavage sites and hydrolytic fragments from MMP20/KLK4 digestion were identified for the amelogenin adsorbed on HAP crystals as compared to the amelogenin in solution. These results suggest that the adsorption of amelogenin to HAP results in their preferential and selective degradation and removal from HAP by MMP20 and KLK4 in vitro. Based on these findings, a new degradation model related to enamel crystal growth is proposed.
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Affiliation(s)
- Li Zhu
- Department of Orofacial Sciences, School of Dentistry, University of California, San Francisco San Francisco, CA, USA
| | - Haichuan Liu
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco San Francisco, CA, USA
| | - H Ewa Witkowska
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco San Francisco, CA, USA
| | - Yulei Huang
- Department of Oral Medicine, Guanghua School of Stomatology, Sun Yat-sen University Guangdong, China
| | - Kataro Tanimoto
- Departments of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences Hiroshima, Japan
| | - Wu Li
- Department of Orofacial Sciences, School of Dentistry, University of California, San Francisco San Francisco, CA, USA
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57
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Bartlett JD, Simmer JP. Kallikrein-related peptidase-4 (KLK4): role in enamel formation and revelations from ablated mice. Front Physiol 2014; 5:240. [PMID: 25071586 PMCID: PMC4082239 DOI: 10.3389/fphys.2014.00240] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 06/10/2014] [Indexed: 12/26/2022] Open
Abstract
Enamel development occurs in stages. During the secretory stage, a soft protein rich enamel layer is produced that expands to reach its final thickness. During the maturation stage, proteins are removed and the enamel matures into the hardest substance in the body. KLK4 is expressed during the transition from secretory to the maturation stage and its expression continues throughout maturation. KLK4 is a glycosylated chymotrypsin-like serine protease that cleaves enamel matrix proteins prior to their export out of the hardening enamel layer. Mutations in KLK4 can cause autosomal recessive, non-syndromic enamel malformations in humans and mice. Klk4 ablated mice initially have normal-looking teeth with enamel of full thickness. However, the enamel is soft and protein-rich. Three findings are notable from Klk4 ablated mice: first, enamel rods fall from the interrod enamel leaving behind empty holes where the enamel fractures near the underlying dentin surface. Second, the ~10,000 crystallites that normally fuse to form a solid enamel rod fail to grow together in the ablated mice and can fall out of the rods. Third, and most striking, the crystallites grow substantially in width and thickness (a- and b-axis) in the ablated mice until they almost interlock. The crystallites grow in defined enamel rods, but interlocking is prevented presumably because too much protein remains. Conventional thought holds that enamel proteins bind specifically to the sides of enamel crystals to inhibit growth in width and thickness so that the thin, ribbon-like enamel crystallites grow predominantly in length. Results from Klk4 ablated mice demonstrate that this convention requires updating. An alternative mechanism is proposed whereby enamel proteins serve to form a mold or support structure that shapes and orients the mineral ribbons as they grow in length. The remnants of this support structure must be removed by KLK4 so that the crystallites can interlock to form fully hardened enamel.
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Affiliation(s)
- John D Bartlett
- Harvard School of Dental Medicine Boston, MA ; Department of Mineralized Tissue Biology, The Forsyth Institute Cambridge, MA
| | - James P Simmer
- Department of Biological and Material Sciences, University of Michigan School of Dentistry Ann Arbor, MI, USA
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Quantitatively and kinetically identifying binding motifs of amelogenin proteins to mineral crystals through biochemical and spectroscopic assays. Methods Enzymol 2014; 532:327-41. [PMID: 24188774 DOI: 10.1016/b978-0-12-416617-2.00015-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tooth enamel is the hardest tissue in vertebrate animals. Consisting of millions of carbonated hydroxyapatite crystals, this highly mineralized tissue develops from a protein matrix in which amelogenin is the predominant component. The enamel matrix proteins are eventually and completely degraded and removed by proteinases to form mineral-enriched tooth enamel. Identification of the apatite-binding motifs in amelogenin is critical for understanding the amelogenin-crystal interactions and amelogenin-proteinases interactions during tooth enamel biomineralization. A stepwise strategy is introduced to kinetically and quantitatively identify the crystal-binding motifs in amelogenin, including a peptide screening assay, a competitive adsorption assay, and a kinetic-binding assay using amelogenin and gene-engineered amelogenin mutants. A modified enzyme-linked immunosorbent assay on crystal surfaces is also applied to compare binding amounts of amelogenin and its mutants on different planes of apatite crystals. We describe the detailed protocols for these assays and provide the considerations for these experiments in this chapter.
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59
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Horvath JE, Ramachandran GL, Fedrigo O, Nielsen WJ, Babbitt CC, St Clair EM, Pfefferle LW, Jernvall J, Wray GA, Wall CE. Genetic comparisons yield insight into the evolution of enamel thickness during human evolution. J Hum Evol 2014; 73:75-87. [PMID: 24810709 DOI: 10.1016/j.jhevol.2014.01.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 10/29/2013] [Accepted: 01/09/2014] [Indexed: 12/29/2022]
Abstract
Enamel thickness varies substantially among extant hominoids and is a key trait with significance for interpreting dietary adaptation, life history trajectory, and phylogenetic relationships. There is a strong link in humans between enamel formation and mutations in the exons of the four genes that code for the enamel matrix proteins and the associated protease. The evolution of thick enamel in humans may have included changes in the regulation of these genes during tooth development. The cis-regulatory region in the 5' flank (upstream non-coding region) of MMP20, which codes for enamelysin, the predominant protease active during enamel secretion, has previously been shown to be under strong positive selection in the lineages leading to both humans and chimpanzees. Here we examine evidence for positive selection in the 5' flank and 3' flank of AMELX, AMBN, ENAM, and MMP20. We contrast the human sequence changes with other hominoids (chimpanzees, gorillas, orangutans, gibbons) and rhesus macaques (outgroup), a sample comprising a range of enamel thickness. We find no evidence for positive selection in the protein-coding regions of any of these genes. In contrast, we find strong evidence for positive selection in the 5' flank region of MMP20 and ENAM along the lineage leading to humans, and in both the 5' flank and 3' flank regions of MMP20 along the lineage leading to chimpanzees. We also identify putative transcription factor binding sites overlapping some of the species-specific nucleotide sites and we refine which sections of the up- and downstream putative regulatory regions are most likely to harbor important changes. These non-coding changes and their potential for differential regulation by transcription factors known to regulate tooth development may offer insight into the mechanisms that allow for rapid evolutionary changes in enamel thickness across closely-related species, and contribute to our understanding of the enamel phenotype in hominoids.
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Affiliation(s)
- Julie E Horvath
- North Carolina Museum of Natural Sciences, Nature Research Center, Raleigh, NC 27601, USA; Department of Biology, North Carolina Central University, Durham, NC 27707, USA; Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA; Duke Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708, USA
| | | | - Olivier Fedrigo
- Duke Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708, USA
| | | | - Courtney C Babbitt
- Duke Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708, USA; Department of Biology, Duke University, Durham, NC 27708, USA
| | | | | | - Jukka Jernvall
- Institute for Biotechnology, University of Helsinki, Helsinki, Finland
| | - Gregory A Wray
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA; Duke Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708, USA; Department of Biology, Duke University, Durham, NC 27708, USA
| | - Christine E Wall
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA.
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McGuire JD, Mousa AA, Zhang BJ, Todoki LS, Huffman NT, Chandrababu KB, Moradian-Oldak J, Keightley A, Wang Y, Walker MP, Gorski JP. Extracts of irradiated mature human tooth crowns contain MMP-20 protein and activity. J Dent 2014; 42:626-35. [PMID: 24607847 DOI: 10.1016/j.jdent.2014.02.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 01/17/2014] [Accepted: 02/18/2014] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVES We recently demonstrated a significant correlation between enamel delamination and tooth-level radiation dose in oral cancer patients. Since radiation can induce the synthesis and activation of matrix metalloproteinases, we hypothesized that irradiated teeth may contain active matrix metalloproteinases. MATERIALS AND METHODS Extracted teeth from oral cancer patients treated with radiotherapy and from healthy subjects were compared. Extracted mature third molars from healthy subjects were irradiated in vitro and/or incubated for 0-6 months at 37°C. All teeth were then pulverized, extracted, and extracts subjected to proteomic and enzymatic analyses. RESULTS Screening of irradiated crown extracts using mass spectrometry identified MMP-20 (enamelysin) which is expressed developmentally in dentine and enamel but believed to be removed prior to tooth eruption. MMP-20 was composed of catalytically active forms at Mr=43, 41, 24 and 22kDa and was immunolocalized predominantly to the morphological dentine enamel junction. The proportion of different sized MMP-20 forms changed with incubation and irradiation. While the pattern was not altered directly by irradiation of healthy teeth with 70Gy, subsequent incubation at 37°C for 3-6 months with or without prior irradiation caused the proportion of Mr=24-22kDa MMP-20 bands to increase dramatically. Extracts of teeth from oral cancer patients who received >70Gy radiation also contained relatively more 24 and 22kDa MMP-20 than those of healthy age-related teeth. CONCLUSION MMP-20 is a radiation-resistant component of mature tooth crowns enriched in the dentine-enamel. We speculate that MMP-20 catalyzed degradation of organic matrix at this site could lead to enamel delamination associated with oral cancer radiotherapy.
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Affiliation(s)
- J D McGuire
- Department of Oral and Craniofacial Science, Center of Excellence in Dental and Musculoskeletal Tissues, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States
| | - A A Mousa
- Department of Oral and Craniofacial Science, Center of Excellence in Dental and Musculoskeletal Tissues, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Bo J Zhang
- Department of Oral and Craniofacial Science, Center of Excellence in Dental and Musculoskeletal Tissues, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States
| | - L S Todoki
- Department of Oral and Craniofacial Science, Center of Excellence in Dental and Musculoskeletal Tissues, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States
| | - N T Huffman
- Department of Oral and Craniofacial Science, Center of Excellence in Dental and Musculoskeletal Tissues, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States
| | - K B Chandrababu
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, United States
| | - J Moradian-Oldak
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, United States
| | - A Keightley
- Biological Mass Spectrometry and Proteomics Facility, School of Biological Sciences, University of Missouri-Kansas City, MO, United States
| | - Y Wang
- Department of Oral and Craniofacial Science, Center of Excellence in Dental and Musculoskeletal Tissues, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States
| | - M P Walker
- Department of Oral and Craniofacial Science, Center of Excellence in Dental and Musculoskeletal Tissues, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States
| | - J P Gorski
- Department of Oral and Craniofacial Science, Center of Excellence in Dental and Musculoskeletal Tissues, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States.
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61
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Shin M, Hu Y, Tye CE, Guan X, Deagle CC, Antone JV, Smith CE, Simmer JP, Bartlett JD. Matrix metalloproteinase-20 over-expression is detrimental to enamel development: a Mus musculus model. PLoS One 2014; 9:e86774. [PMID: 24466234 PMCID: PMC3900650 DOI: 10.1371/journal.pone.0086774] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 12/17/2013] [Indexed: 12/25/2022] Open
Abstract
Background Matrix metalloproteinase-20 (Mmp20) ablated mice have enamel that is thin and soft with an abnormal rod pattern that abrades from the underlying dentin. We asked if introduction of transgenes expressing Mmp20 would revert this Mmp20 null phenotype back to normal. Unexpectedly, for transgenes expressing medium or high levels of Mmp20, we found opposite enamel phenotypes depending on the genetic background (Mmp20−/− or Mmp20+/+) in which the transgenes were expressed. Methodology/Principal Findings Amelx-promoter-Mmp20 transgenic founder mouse lines were assessed for transgene expression and those expressing low, medium or high levels of Mmp20 were selected for breeding into the Mmp20 null background. Regardless of expression level, each transgene brought the null enamel back to full thickness. However, the high and medium expressing Mmp20 transgenes in the Mmp20 null background had significantly harder more mineralized enamel than did the low transgene expresser. Strikingly, when the high and medium expressing Mmp20 transgenes were present in the wild-type background, the enamel was significantly less well mineralized than normal. Protein gel analysis of enamel matrix proteins from the high and medium expressing transgenes present in the wild-type background demonstrated that greater than normal amounts of cleavage products and smaller quantities of higher molecular weight proteins were present within their enamel matrices. Conclusions/Significance Mmp20 expression levels must be within a specific range for normal enamel development to occur. Creation of a normally thick enamel layer may occur over a wider range of Mmp20 expression levels, but acquisition of normal enamel hardness has a narrower range. Since over-expression of Mmp20 results in decreased enamel hardness, this suggests that a balance exists between cleaved and full-length enamel matrix proteins that are essential for formation of a properly hardened enamel layer. It also suggests that few feedback controls are present in the enamel matrix to prevent excessive MMP20 activity.
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Affiliation(s)
- Masashi Shin
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
| | - Yuanyuan Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan, United States of America
| | - Coralee E. Tye
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
| | - Xiaomu Guan
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
| | - Craig C. Deagle
- Program in Endodontics, Harvard School of Dental Medicine, Boston Massachusetts, United States of America
| | - Jerry V. Antone
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
| | - Charles E. Smith
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan, United States of America
- Facility for Electron Microscopy Research, Department of Anatomy & Cell Biology, and Faculty of Dentistry, McGill University, Montreal, QC, Canada
| | - James P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan, United States of America
| | - John D. Bartlett
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, Cambridge Massachusetts, United States of America
- * E-mail:
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Dong Y, Loessner D, Irving-Rodgers H, Obermair A, Nicklin JL, Clements JA. Metastasis of ovarian cancer is mediated by kallikrein related peptidases. Clin Exp Metastasis 2014; 31:135-47. [PMID: 24043563 PMCID: PMC3892111 DOI: 10.1007/s10585-013-9615-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 08/26/2013] [Indexed: 12/16/2022]
Abstract
Ovarian cancer, in particular epithelial ovarian cancer (EOC), is commonly diagnosed when the tumor has metastasized into the abdominal cavity with an accumulation of ascites fluid. Combining histopathology and genetic variations, EOC can be sub-grouped into Type-I and Type-II tumors, of which the latter are more aggressive and metastatic. Metastasis and chemoresistance are the key events associated with the tumor microenvironment that lead to a poor patient outcome. Kallikrein-related peptidases (KLKs) are aberrantly expressed in EOC, in particular, in the more metastatic Type-II tumors. KLKs are a family of 15 serine proteases that are expressed in diverse human tissues and involved in various patho-physiological processes. As extracellular enzymes, KLKs function in the hydrolysis of growth factors, proteases, cell membrane bound receptors, adhesion proteins, and cytokines initiating intracellular signaling pathways and their downstream events. High KLK levels are differentially associated with the prognosis of ovarian cancer patients, suggesting that they not only have application as biomarkers but also function in disease progression, and therefore are potential therapeutic targets. Recent studies have demonstrated the function of these proteases in promoting and/or suppressing the invasive behavior of ovarian cancer cells in metastasis in vitro and in vivo. Both conventional cell culture methods and three-dimensional platforms have been applied to mimic the ovarian cancer microenvironment of patients, such as the solid stromal matrix and ascites fluid. Here we summarize published studies to provide an overview of our understanding of the role of KLKs in EOC, and to lay the foundation for future research directions.
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Affiliation(s)
- Ying Dong
- Cancer Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia,
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Pugach MK, Suggs C, Li Y, Wright JT, Kulkarni AB, Bartlett JD, Gibson CW. M180 amelogenin processed by MMP20 is sufficient for decussating murine enamel. J Dent Res 2013; 92:1118-22. [PMID: 24072097 DOI: 10.1177/0022034513506444] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Amelogenin (AMELX) and matrix metalloproteinase-20 (MMP20) are essential for proper enamel development. Amelx and Mmp20 mutations cause amelogenesis imperfecta. MMP20, a protease secreted by ameloblasts, is responsible for processing enamel proteins, including AMELX, during the secretory stage of enamel formation. Of at least 16 different amelogenin splice products, the most abundant isoform found in murine ameloblasts and developing enamel is the M180 protein. To understand the role of MMP20 processing of M180 AMELX, we generated AmelxKO/Mmp20KO (DKO) mice with an amelogenin (M180Tg) transgene. We analyzed the enamel phenotype by SEM to determine enamel structure and thickness, µCT, and by nanoindentation to quantify enamel mechanical properties. M180Tg/DKO mouse enamel had 37% of the hardness of M180Tg/AmelxKO teeth and demonstrated a complete lack of normal prismatic architecture. Although molar enamel of M180Tg/AmelxKO mice was thinner than WT, it had similar mechanical properties and decussating enamel prisms, which were abolished by the loss of MMP20 in the M180Tg/DKO mice. Retention of the C-terminus or complete lack of this domain is unable to rescue amelogenin null enamel. We conclude that among amelogenins, M180 alone is sufficient for normal enamel mechanical properties and prism patterns, but that additional amelogenin splice products are required to restore enamel thickness.
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Affiliation(s)
- M K Pugach
- Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, 240 S. 40th Street, Philadelphia, PA 19104-6030, USA
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Guan X, Bartlett JD. MMP20 modulates cadherin expression in ameloblasts as enamel develops. J Dent Res 2013; 92:1123-8. [PMID: 24067343 DOI: 10.1177/0022034513506581] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Matrix metalloproteinase-20 (enamelysin, MMP20) is essential for dental enamel development. Seven different MMP20 mutations in humans cause non-syndromic enamel malformations, termed amelogenesis imperfecta, and ablation of Mmp20 in mice results in thin brittle enamel with a dysplastic rod pattern. Healthy enamel formation requires the sliding movement of ameloblasts in rows during the secretory stage of development. This is essential for formation of the characteristic decussating enamel rod pattern observed in rodents, and this is also when MMP20 is secreted into the enamel matrix. Therefore, we propose that MMP20 facilitates ameloblast movement by cleaving ameloblast cell-cell contacts. Here we show that MMP20 cleaves the extracellular domains of the E- and N-cadherin adherens junction proteins, that both E- and N-cadherin transcripts are expressed at significantly higher levels in Mmp20 null vs. wild-type (WT) mice, and that in Mmp20 ablated mice, high-level ameloblast N-cadherin expression persists during the maturation stage of development. Furthermore, we show that E-cadherin gene expression is down-regulated from the pre-secretory to the secretory stage, while N-cadherin levels are up-regulated. This E- to N-cadherin switch supports epithelial migration in other tissues and may be an important event necessary for the ameloblasts to start moving in rows that slide by one another.
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Affiliation(s)
- X Guan
- Department of Mineralized Tissue Biology and Harvard School of Dental Medicine, The Forsyth Institute, 245 First Street, Cambridge, MA 02142, USA
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Bartlett JD. Dental enamel development: proteinases and their enamel matrix substrates. ISRN DENTISTRY 2013; 2013:684607. [PMID: 24159389 PMCID: PMC3789414 DOI: 10.1155/2013/684607] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 07/15/2013] [Indexed: 12/31/2022]
Abstract
This review focuses on recent discoveries and delves in detail about what is known about each of the proteins (amelogenin, ameloblastin, and enamelin) and proteinases (matrix metalloproteinase-20 and kallikrein-related peptidase-4) that are secreted into the enamel matrix. After an overview of enamel development, this review focuses on these enamel proteins by describing their nomenclature, tissue expression, functions, proteinase activation, and proteinase substrate specificity. These proteins and their respective null mice and human mutations are also evaluated to shed light on the mechanisms that cause nonsyndromic enamel malformations termed amelogenesis imperfecta. Pertinent controversies are addressed. For example, do any of these proteins have a critical function in addition to their role in enamel development? Does amelogenin initiate crystallite growth, does it inhibit crystallite growth in width and thickness, or does it do neither? Detailed examination of the null mouse literature provides unmistakable clues and/or answers to these questions, and this data is thoroughly analyzed. Striking conclusions from this analysis reveal that widely held paradigms of enamel formation are inadequate. The final section of this review weaves the recent data into a plausible new mechanism by which these enamel matrix proteins support and promote enamel development.
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Affiliation(s)
- John D. Bartlett
- Harvard School of Dental Medicine & Chair, Department of Mineralized Tissue Biology, The Forsyth Institute, 245 First Street, Cambridge MA 02142, USA
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High amounts of fluoride induce apoptosis/cell death in matured ameloblast-like LS8 cells by downregulating Bcl-2. Arch Oral Biol 2013; 58:1165-73. [DOI: 10.1016/j.archoralbio.2013.03.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/23/2013] [Accepted: 03/20/2013] [Indexed: 01/24/2023]
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Gallon V, Chen L, Yang X, Moradian-Oldak J. Localization and quantitative co-localization of enamelin with amelogenin. J Struct Biol 2013; 183:239-49. [PMID: 23563189 PMCID: PMC3737400 DOI: 10.1016/j.jsb.2013.03.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 03/11/2013] [Accepted: 03/25/2013] [Indexed: 02/07/2023]
Abstract
Enamelin and amelogenin are vital proteins in enamel formation. The cooperative function of these two proteins controls crystal nucleation and morphology in vitro. We quantitatively analyzed the co-localization between enamelin and amelogenin by confocal microscopy and using two antibodies, one raised against a sequence in the porcine 32 kDa enamelin region and the other raised against full-length recombinant mouse amelogenin. We further investigated the interaction of the porcine 32 kDa enamelin and recombinant amelogenin using immuno-gold labeling. This study reports the quantitative co-localization results for postnatal days 1-8 mandibular mouse molars. We show that amelogenin and enamelin are secreted into the extracellular matrix on the cuspal slopes of the molars at day 1 and that secretion continues to at least day 8. Quantitative co-localization analysis (QCA) was performed in several different configurations using large (45 μm height, 33 μm width) and small (7 μm diameter) regions of interest to elucidate any patterns. Co-localization patterns in day 8 samples revealed that enamelin and amelogenin co-localize near the secretory face of the ameloblasts and appear to be secreted approximately in a 1:1 ratio. The degree of co-localization decreases as the enamel matures, both along the secretory face of ameloblasts and throughout the entire thickness of the enamel. Immuno-reactivity against enamelin is concentrated along the secretory face of ameloblasts, supporting the theory that this protein together with amelogenin is intimately involved in mineral induction at the beginning of enamel formation.
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Affiliation(s)
- Victoria Gallon
- Center for Craniofacial Molecular Biology, University of Southern California, Herman Ostrow School of Dentistry, Los Angeles, CA 90033, USA
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Ruan Q, Zhang Y, Yang X, Nutt S, Moradian-Oldak J. An amelogenin-chitosan matrix promotes assembly of an enamel-like layer with a dense interface. Acta Biomater 2013; 9:7289-97. [PMID: 23571002 PMCID: PMC3669649 DOI: 10.1016/j.actbio.2013.04.004] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/04/2013] [Accepted: 04/01/2013] [Indexed: 10/27/2022]
Abstract
Biomimetic reconstruction of tooth enamel is a significant topic of study in materials science and dentistry as a novel approach to the prevention, restoration, and treatment of defective enamel. We have developed a new amelogenin-containing chitosan hydrogel for enamel reconstruction that works through amelogenin supramolecular assembly, stabilizing Ca-P clusters and guiding their arrangement into linear chains. These amelogenin Ca-P composite chains further fuse with enamel crystals and eventually evolve into enamel-like co-aligned crystals, anchored to the natural enamel substrate through a cluster growth process. A dense interface between the newly grown layer and natural enamel was formed and the enamel-like layer improved the hardness and elastic modulus compared with etched enamel. We anticipate that this chitosan hydrogel will provide effective protection against secondary caries because of its pH-responsive and antimicrobial properties. Our studies introduce an amelogenin-containing chitosan hydrogel as a promising biomaterial for enamel repair and demonstrate the potential of applying protein-directed assembly to biomimetic reconstruction of complex biomaterials.
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Affiliation(s)
- Qichao Ruan
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA
| | - Yuzheng Zhang
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA
| | - Xiudong Yang
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA
| | - Steven Nutt
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA
| | - Janet Moradian-Oldak
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA
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Khan F, Liu H, Reyes A, Witkowska HE, Martinez-Avila O, Zhu L, Li W, Habelitz S. The proteolytic processing of amelogenin by enamel matrix metalloproteinase (MMP-20) is controlled by mineral ions. Biochim Biophys Acta Gen Subj 2013. [PMID: 23201201 DOI: 10.1016/j.bbagen.2012.11.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Enamel synthesis is a highly dynamic process characterized by simultaneity of matrix secretion, assembly and processing during apatite mineralization. MMP-20 is the first protease to hydrolyze amelogenin, resulting in specific cleavage products that self-assemble into nanostructures at specific mineral compositions and pH. In this investigation, enzyme kinetics of MMP-20 proteolysis of recombinant full-length human amelogenin (rH174) under different mineral compositions is elucidated. METHODS Recombinant amelogenin was cleaved by MMP-20 under various physicochemical conditions and the products were analyzed by SDS-PAGE and MALDI-TOF MS. RESULTS It was observed that mineral ions largely affect cleavage pattern, and enzyme kinetics of rH174 hydrolysis. Out of the five selected mineral ion compositions, MMP-20 was most efficient at high calcium concentration, whereas it was slowest at high phosphate, and at high calcium and phosphate concentrations. In most of the compositions, N- and C-termini were cleaved rapidly at several places but the central region of amelogenin was protected up to some extent in solutions with high calcium and phosphate contents. CONCLUSION These in vitro studies showed that the chemistry of the protein solutions can significantly alter the processing of amelogenin by MMP-20, which may have significant effects in vivo matrix assembly and subsequent calcium phosphate mineralization. GENERAL SIGNIFICANCE This study elaborates the possibilities of the processing of the organic matrix into mineralized tissue during enamel development.
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Affiliation(s)
- Feroz Khan
- Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California, 707 Parnassus Avenue, San Francisco, CA 94143, USA
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Immunocytochemical and biochemical detection of the urokinase-type plasminogen activator receptor (uPAR) in the rat tooth germ and in lipid rafts of PMA-stimulated dental epithelial cells. Histochem Cell Biol 2013; 140:649-58. [DOI: 10.1007/s00418-013-1109-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2013] [Indexed: 11/25/2022]
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Lacruz RS, Brookes SJ, Wen X, Jimenez JM, Vikman S, Hu P, White SN, Lyngstadaas SP, Okamoto CT, Smith CE, Paine ML. Adaptor protein complex 2-mediated, clathrin-dependent endocytosis, and related gene activities, are a prominent feature during maturation stage amelogenesis. J Bone Miner Res 2013; 28:672-87. [PMID: 23044750 PMCID: PMC3562759 DOI: 10.1002/jbmr.1779] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 09/14/2012] [Accepted: 09/18/2012] [Indexed: 12/14/2022]
Abstract
Molecular events defining enamel matrix removal during amelogenesis are poorly understood. Early reports have suggested that adaptor proteins (AP) participate in ameloblast-mediated endocytosis. Enamel formation involves the secretory and maturation stages, with an increase in resorptive function during the latter. Here, using real-time PCR, we show that the expression of clathrin and adaptor protein subunits are upregulated in maturation stage rodent enamel organ cells. AP complex 2 (AP-2) is the most upregulated of the four distinct adaptor protein complexes. Immunolocalization confirms the presence of AP-2 and clathrin in ameloblasts, with strongest reactivity at the apical pole. These data suggest that the resorptive functions of enamel cells involve AP-2 mediated, clathrin-dependent endocytosis, thus implying the likelihood of specific membrane-bound receptor(s) of enamel matrix protein debris. The mRNA expression of other endocytosis-related gene products is also upregulated during maturation including: lysosomal-associated membrane protein 1 (Lamp1); cluster of differentiation 63 and 68 (Cd63 and Cd68); ATPase, H(+) transporting, lysosomal V0 subunit D2 (Atp6v0d2); ATPase, H(+) transporting, lysosomal V1 subunit B2 (Atp6v1b2); chloride channel, voltage-sensitive 7 (Clcn7); and cathepsin K (Ctsk). Immunohistologic data confirms the expression of a number of these proteins in maturation stage ameloblasts. The enamel of Cd63-null mice was also examined. Despite increased mRNA and protein expression in the enamel organ during maturation, the enamel of Cd63-null mice appeared normal. This may suggest inherent functional redundancies between Cd63 and related gene products, such as Lamp1 and Cd68. Ameloblast-like LS8 cells treated with the enamel matrix protein complex Emdogain showed upregulation of AP-2 and clathrin subunits, further supporting the existence of a membrane-bound receptor-regulated pathway for the endocytosis of enamel matrix proteins. These data together define an endocytotic pathway likely used by ameloblasts to remove the enamel matrix during enamel maturation.
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Affiliation(s)
- Rodrigo S Lacruz
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90605, USA
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Organic anion transport during rat enamel formation. J Oral Biosci 2013. [DOI: 10.1016/j.job.2012.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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73
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Lacruz RS, Smith CE, Kurtz I, Hubbard MJ, Paine ML. New paradigms on the transport functions of maturation-stage ameloblasts. J Dent Res 2012; 92:122-9. [PMID: 23242231 DOI: 10.1177/0022034512470954] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Fully matured dental enamel is an architecturally and mechanically complex hydroxyapatite-based bioceramic devoid of most of the organic material that was essential in its making. Enamel formation is a staged process principally involving secretory and maturation stages, each associated with major changes in gene expression and cellular function. Cellular activities that define the maturation stage of amelogenesis include ion (e.g., calcium and phosphate) transport and storage, control of intracellular and extracellular pH (e.g., bicarbonate and hydrogen ion movements), and endocytosis. Recent studies on rodent amelogenesis have identified a multitude of gene products that appear to be linked to these cellular activities. This review describes the main cellular activities of these genes during the maturation stage of amelogenesis.
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Affiliation(s)
- R S Lacruz
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA.
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Bromley KM, Lakshminarayanan R, Thompson M, Lokappa SB, Gallon VA, Cho KR, Qiu SR, Moradian-Oldak J. Amelogenin processing by MMP-20 prevents protein occlusion inside calcite crystals. CRYSTAL GROWTH & DESIGN 2012; 12:4897-4905. [PMID: 23226976 PMCID: PMC3513936 DOI: 10.1021/cg300754a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Calcite crystals were grown in the presence of full-length amelogenin and during its proteolysis by recombinant human matrix metalloproteinase 20 (rhMMP-20). Recombinant porcine amelogenin (rP172) altered the shape of calcite crystals by inhibiting the growth of steps on the {104} faces and became occluded inside the crystals. Upon co-addition of rhMMP-20, the majority of the protein was digested resulting in a truncated amelogenin lacking the C-terminal segment. In rP172-rhMMP-20 samples, the occlusion of amelogenin into the calcite crystals was drastically decreased. Truncated amelogenin (rP147) and the 25-residue C-terminal domain produced crystals with regular shape and less occluded organic material. Removal of the C-terminal diminished the affinity of amelogenin to the crystals and therefore prevented occlusion. We hypothesize that HAP and calcite interact with amelogenin in a similar manner. In the case of each material, full-length amelogenin binds most strongly, truncated amelogenin binds weakly and the C-terminus alone has the weakest interaction. Regarding enamel crystal growth, the prevention of occlusion into maturing enamel crystals might be a major benefit resulting from the selective cleavage of amelogenin at the C-terminus by MMP-20. Our data have important implications for understanding the hypomineralized enamel phenotype in cases of amelogenesis imperfecta resulting from MMP-20 mutations and will contribute to the design of enamel inspired biomaterials.
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Affiliation(s)
- Keith M. Bromley
- Center for Craniofacial Molecular Biology, University of Southern California, 2250 Alcazar Street, Los Angeles, CA 90033, USA
| | - Rajamani Lakshminarayanan
- Centre for Translational Medicine, NUS, Yong Loo Lin School of Medicine, 14 Medical Drive, Singapore Eye Research Institute (SERI), Level 8-South Core, Singapore 117599
| | - Mitchell Thompson
- Center for Craniofacial Molecular Biology, University of Southern California, 2250 Alcazar Street, Los Angeles, CA 90033, USA
| | - Sowmya B. Lokappa
- Center for Craniofacial Molecular Biology, University of Southern California, 2250 Alcazar Street, Los Angeles, CA 90033, USA
| | - Victoria A. Gallon
- Center for Craniofacial Molecular Biology, University of Southern California, 2250 Alcazar Street, Los Angeles, CA 90033, USA
| | - Kang R. Cho
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
- Lawrence Berkeley National Laboratory, One Cyclotron Rd., MS 67R1235A, Berkeley, CA 94720, USA
| | - S. Roger Qiu
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Janet Moradian-Oldak
- Center for Craniofacial Molecular Biology, University of Southern California, 2250 Alcazar Street, Los Angeles, CA 90033, USA
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Abstract
Dental enamel is a hypermineralized tissue, containing only trace amounts of organic components. During enamel formation, matrix metalloproteinase 20 (MMP20) processes proteins comprising enamel matrix and facilitates hypermineralization. In the human genome, 24 distinct MMP genes have been identified. Among these genes, MMP20 is clustered with eight other genes, including MMP13, and all these clustered genes show phylogenetically close relationships. In this study, we investigated MMP20 and closely related MMP genes in various tetrapods and in a teleost fish, fugu. In the genome of the chicken, a toothless tetrapod, we identified degraded exons of MMP20, which supports the previous proposition that MMP20 is important specifically for enamel formation. Nevertheless, for unknown reasons, we failed to identify MMP20 in the platypus genome. In the opossum, lizard, and frog genomes, MMP20 was found clustered with MMP13. Furthermore, in the fugu genome, we identified an MMP20-like gene located adjacent to MMP13, suggesting that MMP20 arose before the divergence of ray-finned fish and lobe-finned fish. The teleost tooth surface is covered with enameloid, a hypermineralized tissue different from enamel. Thus, we hypothesize that MMP20 could have been used in an ancient hypermineralized tissue, which evolved into enameloid in teleosts and into enamel in tetrapods.
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Affiliation(s)
- Kazuhiko Kawasaki
- Department of Anthropology, Pennsylvania State University, University Park, PA 16802, USA.
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Bartlett JD, Skobe Z, Nanci A, Smith CE. Matrix metalloproteinase 20 promotes a smooth enamel surface, a strong dentino-enamel junction, and a decussating enamel rod pattern. Eur J Oral Sci 2012; 119 Suppl 1:199-205. [PMID: 22243247 DOI: 10.1111/j.1600-0722.2011.00864.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mutations of the matrix metalloproteinase 20 (MMP20, enamelysin) gene cause autosomal-recessive amelogenesis imperfecta, and Mmp20 ablated mice also have malformed dental enamel. Here we showed that Mmp20 null mouse secretory-stage ameloblasts maintain a columnar shape and are present as a single layer of cells. However, the maturation-stage ameloblasts from null mouse cover extraneous nodules of ectopic calcified material formed at the enamel surface. Remarkably, nodule formation occurs in null mouse enamel when MMP20 is normally no longer expressed. The malformed enamel in Mmp20 null teeth was loosely attached to the dentin and the entire enamel layer tended to separate from the dentin, indicative of a faulty dentino-enamel junction (DEJ). The enamel rod pattern was also altered in Mmp20 null mice. Each enamel rod is formed by a single ameloblast and is a mineralized record of the migration path of the ameloblast that formed it. The enamel rods in Mmp20 null mice were grossly malformed or absent, indicating that the ameloblasts do not migrate properly when backing away from the DEJ. Thus, MMP20 is required for ameloblast cell movement necessary to form the decussating enamel rod patterns, for the prevention of ectopic mineral formation, and to maintain a functional DEJ.
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Affiliation(s)
- John D Bartlett
- Department of Cytokine Biology, Forsyth Institute, Cambridge, MA 02142, USA.
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Gibson CW, Li Y, Suggs C, Kuehl MA, Pugach MK, Kulkarni AB, Wright JT. Rescue of the murine amelogenin null phenotype with two amelogenin transgenes. Eur J Oral Sci 2012; 119 Suppl 1:70-4. [PMID: 22243230 DOI: 10.1111/j.1600-0722.2011.00882.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The amelogenin proteins are required for normal enamel development, and the most abundant amelogenins expressed from alternatively spliced mRNAs are M180 and leucine-rich amelogenin protein (LRAP). The X-Chromosomal Amelogenin (Amelx) null [knockout (KO)] mouse has an enamel defect similar to human X-linked amelogenesis imperfecta. The disorganized enamel layer in KO mice is 10-20% of the thickness of wild-type (WT) enamel and lacks prismatic structures. When the KO mice were mated with mice that express the transgene M180-87, (TgM180-87) partial rescue of the phenotype was observed such that enamel thickness, volume, and density increased. A second transgene was introduced by mating TgM180 KO mice with TgLRAP mice, and male offspring were characterized for genotype and tooth phenotype was evaluated by scanning electron microscopy. The molar enamel thickness of TgM180-LRAP KO mice was further increased, and the structure was improved, with a more defined decussation pattern compared with singly rescued mice. We conclude that TgM180 provides significant rescue of the KO phenotype. Although the effectiveness of the LRAP transgene, alone, to rescue is less obvious, the addition of the LRAP transgene to the M180 transgene in KO enamel leads to an added improvement in both amount and structure and thus these transgenes function in a complementary manner. Together, the two most abundant amelogenins lead to the formation of obvious enamel decussation patterns.
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Affiliation(s)
- Carolyn W Gibson
- Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA 19104, USA.
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78
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Feng J, McDaniel JS, Chuang HH, Huang O, Rakian A, Xu X, Steffensen B, Donly KJ, MacDougall M, Chen S. Binding of amelogenin to MMP-9 and their co-expression in developing mouse teeth. J Mol Histol 2012; 43:473-85. [PMID: 22648084 PMCID: PMC3460178 DOI: 10.1007/s10735-012-9423-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 04/29/2012] [Indexed: 12/02/2022]
Abstract
Amelogenin is the most abundant matrix protein in enamel. Proper amelogenin processing by proteinases is necessary for its biological functions during amelogenesis. Matrix metalloproteinase 9 (MMP-9) is responsible for the turnover of matrix components. The relationship between MMP-9 and amelogenin during tooth development remains unknown. We tested the hypothesis that MMP-9 binds to amelogenin and they are co-expressed in ameloblasts during amelogenesis. We evaluated the distribution of both proteins in the mouse teeth using immunohistochemistry and confocal microscopy. At postnatal day 2, the spatial distribution of amelogenin and MMP-9 was co-localized in preameloblasts, secretory ameloblasts, enamel matrix and odontoblasts. At the late stages of mouse tooth development, expression patterns of amelogenin and MMP-9 were similar to that seen in postnatal day 2. Their co-expression was further confirmed by RT-PCR, Western blot and enzymatic zymography analyses in enamel organ epithelial and odontoblast-like cells. Immunoprecipitation assay revealed that MMP-9 binds to amelogenin. The MMP-9 cleavage sites in amelogenin proteins across species were found using bio-informative software program. Analyses of these data suggest that MMP-9 may be involved in controlling amelogenin processing and enamel formation.
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Affiliation(s)
- Junsheng Feng
- Department of Developmental Dentistry, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA
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79
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Lacruz RS, Smith CE, Bringas P, Chen YB, Smith SM, Snead ML, Kurtz I, Hacia JG, Hubbard MJ, Paine ML. Identification of novel candidate genes involved in mineralization of dental enamel by genome-wide transcript profiling. J Cell Physiol 2012; 227:2264-75. [PMID: 21809343 DOI: 10.1002/jcp.22965] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The gene repertoire regulating vertebrate biomineralization is poorly understood. Dental enamel, the most highly mineralized tissue in mammals, differs from other calcifying systems in that the formative cells (ameloblasts) lack remodeling activity and largely degrade and resorb the initial extracellular matrix. Enamel mineralization requires that ameloblasts undergo a profound functional switch from matrix-secreting to maturational (calcium transport, protein resorption) roles as mineralization progresses. During the maturation stage, extracellular pH decreases markedly, placing high demands on ameloblasts to regulate acidic environments present around the growing hydroxyapatite crystals. To identify the genetic events driving enamel mineralization, we conducted genome-wide transcript profiling of the developing enamel organ from rat incisors and highlight over 300 genes differentially expressed during maturation. Using multiple bioinformatics analyses, we identified groups of maturation-associated genes whose functions are linked to key mineralization processes including pH regulation, calcium handling, and matrix turnover. Subsequent qPCR and Western blot analyses revealed that a number of solute carrier (SLC) gene family members were up-regulated during maturation, including the novel protein Slc24a4 involved in calcium handling as well as other proteins of similar function (Stim1). By providing the first global overview of the cellular machinery required for enamel maturation, this study provide a strong foundation for improving basic understanding of biomineralization and its practical applications in healthcare.
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Affiliation(s)
- Rodrigo S Lacruz
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA.
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80
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Abstract
Amelogenin plays a key role in the formation of the highly mineralized structure of tooth enamel. During the secretory stage, amelogenin is cleaved gradually by a protease, matrix metalloproteinase-20 (MMP-20), releasing hydrophilic C-terminal peptides. In this study, the biophysical properties of synthetic C-terminal peptides (of 28, 17, and 11 residues), mimicking native peptides, were explored in vitro. A sudden decrease was observed in the zeta (ζ)-potential upon the addition of calcium or phosphates, which was also accompanied by an increased aggregation propensity of the peptides. Under most of the experimental conditions, the particle size increased at a pH 2-3 units higher than the isoelectric point (pI) of the peptides, while the peptides existed as smaller particles (<2 nm) near their pI values and in the acidic range. They showed poor affinity for calcium and phosphates, comparable to full-length amelogenin and variants. The secondary structure determination showed that the 11-amino-acid peptide contained defined secondary structure comprising beta-sheets and turns. Atomic force microscopy analysis revealed the presence of thin, disk-like nanostructures of 54.4 nm diameter for the 28-amino-acid peptide and 54.9 nm diameter for the 11-amino acid peptide, whereas no definite structures were observed for the 17-amino-acid peptide. It is concluded that the amelogenin C-terminal peptides are capable of interacting with calcium and phosphate ions, of self-assembly into nanostructures, and may have some secondary structure, and hence may have some role in enamel synthesis.
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Affiliation(s)
- Feroz Khan
- Department of Preventive and Restorative Dental Sciences, University of California, Parnassus Avenue 707, San Francisco, CA 94143, USA
| | - Wu Li
- Department of Oral and Craniofacial Sciences, University of California, San Francisco, USA
| | - Stefan Habelitz
- Department of Preventive and Restorative Dental Sciences, University of California, Parnassus Avenue 707, San Francisco, CA 94143, USA
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81
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Poché RA, Sharma R, Garcia MD, Wada AM, Nolte MJ, Udan RS, Paik JH, DePinho RA, Bartlett JD, Dickinson ME. Transcription factor FoxO1 is essential for enamel biomineralization. PLoS One 2012; 7:e30357. [PMID: 22291941 PMCID: PMC3265481 DOI: 10.1371/journal.pone.0030357] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 12/14/2011] [Indexed: 01/10/2023] Open
Abstract
The Transforming growth factor β (Tgf-β) pathway, by signaling via the activation of Smad transcription factors, induces the expression of many diverse downstream target genes thereby regulating a vast array of cellular events essential for proper development and homeostasis. In order for a specific cell type to properly interpret the Tgf-β signal and elicit a specific cellular response, cell-specific transcriptional co-factors often cooperate with the Smads to activate a discrete set of genes in the appropriate temporal and spatial manner. Here, via a conditional knockout approach, we show that mice mutant for Forkhead Box O transcription factor FoxO1 exhibit an enamel hypomaturation defect which phenocopies that of the Smad3 mutant mice. Furthermore, we determined that both the FoxO1 and Smad3 mutant teeth exhibit changes in the expression of similar cohort of genes encoding enamel matrix proteins required for proper enamel development. These data raise the possibility that FoxO1 and Smad3 act in concert to regulate a common repertoire of genes necessary for complete enamel maturation. This study is the first to define an essential role for the FoxO family of transcription factors in tooth development and provides a new molecular entry point which will allow researchers to delineate novel genetic pathways regulating the process of biomineralization which may also have significance for studies of human tooth diseases such as amelogenesis imperfecta.
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Affiliation(s)
- Ross A. Poché
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ramaswamy Sharma
- Department of Cytokine Biology, Forsyth Institute, and Department of Developmental Biology, Harvard School of Dental Medicine, Cambridge, Massachusetts, United States of America
| | - Monica D. Garcia
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Aya M. Wada
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Mark J. Nolte
- Department of Genetics, University of Texas M. D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Ryan S. Udan
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ji-Hye Paik
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Ronald A. DePinho
- Departments of Medical Oncology, Medicine, and Genetics, Belfer Institute for Applied Cancer Science, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, United States of America
| | - John D. Bartlett
- Department of Cytokine Biology, Forsyth Institute, and Department of Developmental Biology, Harvard School of Dental Medicine, Cambridge, Massachusetts, United States of America
| | - Mary E. Dickinson
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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82
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Porto IM, Laure HJ, Tykot RH, de Sousa FB, Rosa JC, Gerlach RF. Recovery and identification of mature enamel proteins in ancient teeth. Eur J Oral Sci 2012; 119 Suppl 1:83-7. [DOI: 10.1111/j.1600-0722.2011.00885.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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83
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Urzúa B, Ortega-Pinto A, Farias DA, Franco E, Morales-Bozo I, Moncada G, Escobar-Pezoa N, Scholz U, Cifuentes V. A multidisciplinary approach for the diagnosis of hypocalcified amelogenesis imperfecta in two Chilean families. Acta Odontol Scand 2012; 70:7-14. [PMID: 21504268 DOI: 10.3109/00016357.2011.574973] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The purpose of this study was to conduct a multidisciplinary analysis of a specific type of tooth enamel disturbance (amelogenesis imperfecta) affecting two Chilean families to obtain a precise diagnosis and to investigate possible underlying mutations. MATERIALS AND METHODS Two non-related families affected with amelogenesis imperfecta were evaluated with clinical, radiographic and histopathological methods. Furthermore, pedigrees of both families were constructed and the presence of eight mutations in the enamelin gene (ENAM) and three mutations in the enamelysin gene (MMP-20) were investigated by PCR and direct sequencing. RESULTS In the two affected patients, the dental malformation presented as soft and easily disintegrated enamel and exposed dark dentin. Neither of the affected individuals presented with a dental and skeletal open bite. Histologically, a high level of an organic matrix with prismatic organization was found. Genetic analysis indicated that the condition is autosomal recessive in one family and either autosomal recessive or due to a new mutation in the other family. Molecular mutational analysis revealed that none of the eight mutations previously described in the ENAM gene or the three mutations in the MMP-20 gene were present in the probands. CONCLUSION A multidisciplinary analysis allowed for a diagnosis of hypocalcified amelogenesis imperfecta, Witkop type III, which was unrelated to previously described mutations in the ENAM or MMP-20 genes.
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Affiliation(s)
- Blanca Urzúa
- Department of Physical and Chemical Sciences, University of Chile, Santiago de Chile, Chile.
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84
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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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85
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Uskoković V, Khan F, Liu H, Witkowska HE, Zhu L, Li W, Habelitz S. Hydrolysis of amelogenin by matrix metalloprotease-20 accelerates mineralization in vitro. Arch Oral Biol 2011; 56:1548-59. [PMID: 21774914 PMCID: PMC3221888 DOI: 10.1016/j.archoralbio.2011.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 06/24/2011] [Accepted: 06/27/2011] [Indexed: 10/17/2022]
Abstract
In the following respects, tooth enamel is a unique tissue in the mammalian body: (a) it is the most mineralized and hardest tissue in it comprising up to 95 wt% of apatite; (b) its microstructure is dominated by parallel rods composed of bundles of 40-60 nm wide apatite crystals with aspect ratios reaching up to 1:10,000 and (c) not only does the protein matrix that gives rise to enamel guides the crystal growth, but it also conducts its own degradation and removal in parallel. Hence, when mimicking the process of amelogenesis in vitro, crystal growth has to be coupled to proteolytic digestion of the amelogenin assemblies that are known to play a pivotal role in conducting the proper crystal growth. Experimental settings based on controlled and programmable titration of amelogenin sols digested by means of MMP-20 with buffered calcium and phosphate solutions were employed to imitate the formation of elongated, plate-shaped crystals. Whilst amelogenin can act as a promoter of nucleation and crystal growth alone, in this study we show that proteolysis exerts an additional nucleation- and growth-promoting effect. Hydrolysis of full-length amelogenin by MMP-20 decreases the critical time needed for the protein and peptides to adhere and to cover the substrate. The formation and immobilization of a protein layer subsequently reduces the time for calcium phosphate crystallization. Coupling the proteolytic reaction to titration in the presence of 0.4 mg/ml rH174 has been shown to have the same effect on the crystal growth promotion as quadrupling the concentration of rH174 to 1.6 mg/ml. Controlling the rate and the extent of the proteolytic cleavage can thus be used to control the nucleation and growth rates in a protein-guided crystallization system.
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Affiliation(s)
- Vuk Uskoković
- Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California, Parnassus Avenue 707, San Francisco, CA 94143, USA
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86
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Yamakoshi Y, Richardson AS, Nunez SM, Yamakoshi F, Milkovich RN, Hu JCC, Bartlett JD, Simmer JP. Enamel proteins and proteases in Mmp20 and Klk4 null and double-null mice. Eur J Oral Sci 2011; 119 Suppl 1:206-16. [PMID: 22243248 PMCID: PMC3282035 DOI: 10.1111/j.1600-0722.2011.00866.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Matrix metalloproteinase 20 (MMP20) and kallikrein-related peptidase 4 (KLK4) are thought to be necessary to clear proteins from the enamel matrix of developing teeth. We characterized Mmp20 and Klk4 null mice to better understand their roles in matrix degradation and removal. Histological examination showed retained organic matrix in Mmp20, Klk4, and Mmp20/Klk4 double-null mouse enamel matrix, but not in the wild-type. X-gal histostaining of Mmp20 null mice heterozygous for the Klk4 knockout/lacZ knockin showed that Klk4 is expressed normally in the Mmp20 null background. This finding was corroborated by zymogram and western blotting, which discovered a 40-kDa protease induced in the maturation stage of Mmp20 null mice. Proteins were extracted from secretory-stage or maturation-stage maxillary first molars from wild-type, Mmp20 null, Klk4 null, and Mmp20/Klk4 double-null mice and were analyzed by SDS-PAGE and western blotting. Only intact amelogenins and ameloblastin were observed in secretory-stage enamel of Mmp20 null mice, whereas the secretory-stage matrix from Klk4 null mice was identical to the matrix from wild-type mice. More residual matrix was observed in the double-null mice compared with either of the single-null mice. These results support the importance of MMP20 during the secretory stage and of KLK4 during the maturation stage and show there is only limited functional redundancy for these enzymes.
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Affiliation(s)
- Yasuo Yamakoshi
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Amelia S. Richardson
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Stephanie M. Nunez
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Fumiko Yamakoshi
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Rachel N. Milkovich
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Jan C-C. Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - John D. Bartlett
- Department of Cytokine Biology, Forsyth Institute and Department of Developmental Biology, Harvard School of Dental Medicine, Cambridge, MA, USA
| | - James P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
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Brookes SJ, Kingswell NJ, Barron MJ, Dixon MJ, Kirkham J. Is the 32-kDa fragment the functional enamelin unit in all species? Eur J Oral Sci 2011; 119 Suppl 1:345-50. [PMID: 22243266 PMCID: PMC3427898 DOI: 10.1111/j.1600-0722.2011.00869.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Enamelin is an extracellular enamel matrix protein essential for normal amelogenesis. After secretion, porcine enamelin is processed to generate several enamelin-degradation products. The cumulative 32-kDa enamelin is the most abundant enamelin present, and various roles for this molecule have been suggested. However, the proteolytic cleavage sites in porcine enamelin that generate the 32-kDa enamelin are not conserved across species, and the 32-kDa enamelin analogue may not be present in all species. To explore this we studied rat enamelin biochemistry using western blotting with anti-peptide IgGs to porcine 32-kDa enamelin and to the putative rat 32-kDa enamelin analogue. The dominant enamelins in secretory-stage rat enamel migrated at around 60-70 kDa. In contrast, the dominant enamelins in secretory-stage porcine enamel migrated at around 32 kDa. In contrast, secretory-stage porcine-enamel enamelins were dominated by the 32-kDa enamelin. Rat enamelin was completely removed from maturation-stage enamel without any accumulation of 32-kDa enamelin. We suggest that a discrete 32-kDa enamelin is not essential for normal amelogenesis in all species, and in pig it may be a processing product of a larger functional enamelin molecule. The pig may be an atypical model in terms of enamelin biochemistry and function, and caution should be exercised when assigning functional roles to the 32-kDa enamelin as a discrete enamel matrix entity.
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Affiliation(s)
- Steven J Brookes
- Department of Oral Biology, Leeds Dental Institute, University of Leeds, Leeds, UK.
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88
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Abstract
The structures and interactions among macromolecules in the enamel extracellular matrix play vital roles in regulating hydroxyapatite crystal nucleation, growth, and maturation. We used dynamic light scattering (DLS), circular dichroism (CD), fluorescence spectroscopy, and transmission electron microscopy (TEM) to investigate the association of amelogenin and the 32-kDa enamelin, at physiological pH 7.4, in phosphate-buffered saline (PBS). The self-assembly behavior of amelogenin (rP148) was altered following addition of the 32-kDa enamelin. Dynamic light scattering revealed a trend for a decrease in aggregate size in the solution following the addition of enamelin to amelogenin. A blue-shift and intensity increase of the ellipticity minima of rP148 in the CD spectra upon the addition of the 32-kDa enamelin, suggest a direct interaction between the two proteins. In the fluorescence spectra, the maximum emission of rP148 was red-shifted from 335 to 341 nm with a marked intensity increase in the presence of enamelin as a result of complexation of the two proteins. In agreement with DLS data, TEM imaging showed that the 32-kDa enamelin dispersed the amelogenin aggregates into oligomeric particles and stabilized them. Our study provides novel insights into understanding the possible cooperation between enamelin and amelogenin in macromolecular co-assembly and in controlling enamel mineral formation.
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Affiliation(s)
- Xiudong Yang
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA
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89
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Yamakoshi Y, Yamakoshi F, Hu JCC, Simmer JP. Characterization of kallikrein-related peptidase 4 glycosylations. Eur J Oral Sci 2011; 119 Suppl 1:234-40. [PMID: 22243251 PMCID: PMC3282036 DOI: 10.1111/j.1600-0722.2011.00863.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Kallikrein-related peptidase 4 (KLK4) is a glycosylated serine protease that functions in the maturation (hardening) of dental enamel. Pig and mouse KLK4 contain three potential N-glycosylation sites. We isolated KLK4 from developing pig and mouse molars and characterized their N-glycosylations. N-glycans were enzymatically released by digestion with N-glycosidase F and fluorescently labeled with 2-aminobenzoic acid. Normal-phase high-performance liquid chromatography (NP-HPLC) revealed N-glycans with no, or with one, two, or three sialic acid attachments in pig KLK4 and with no, or with one or two sialic acid attachments in mouse KLK4. The labeled N-glycans were digested with sialidase to generate the asialo N-glycan cores that were fractionated by reverse-phase HPLC, and their retention times were compared with similarly labeled glycan standards. The purified cores were characterized by mass spectrometric and monosaccharide composition analyses. We determined that pig and mouse KLK4 have NA2 and NA2F biantennary N-glycan cores. The pig triantennary core is NA3. The mouse triantennary core is NA3 with a fucose connected by an α1-6 linkage, indicating that it is attached to the first N-acetyglucosamine (NA3F). We conclude that pig KLK4 has NA2, NA2F, and NA3 N-glycan cores with no, or with one, two, or three sialic acids. Mouse KLK4 has NA2, NA2F, and NA3F N-glycan cores with no, or with one or two sialic acids.
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Affiliation(s)
- Yasuo Yamakoshi
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Eisenhower Place, Ann Arbor, MI 48108, USA
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90
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Yang X, Sun Z, Ma R, Fan D, Moradian-Oldak J. Amelogenin "nanorods" formation during proteolysis by Mmp-20. J Struct Biol 2011; 176:220-8. [PMID: 21840397 PMCID: PMC3185149 DOI: 10.1016/j.jsb.2011.07.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 07/28/2011] [Accepted: 07/29/2011] [Indexed: 11/19/2022]
Abstract
Amelogenin is cleaved by enamelysin (Mmp-20) soon after its secretion, and the cleavage products accumulate in specific locations during enamel formation, suggesting that parent amelogenin proteolysis is necessary for activating its functions. To investigate the precise roles of Mmp-20 and its influence on the assembly of amelogenin, an in vitro enzymatic digestion process mimicking the initial stages of amelogenin proteolysis was investigated at near-physiological conditions using recombinant porcine amelogenin (rP172) and enamelysin. Hierarchically organized nanorod structures formed during different digestion stages were detected by TEM. At the earliest stage, uniformly dispersed parent amelogenin spherical particles, mixed with some darker stained smaller spheres, and accompanying elongated chain-like nanostructures were observed. Cylindrical nanorods, which appeared to be the result of tight assembly of thin subunit cylindrical discs with thicknesses ranging from ∼2.5 to ∼6.0nm, were formed after an hour of proteolysis. These subunit building blocks stacked to form nanorods with maximum length of ∼100nm. With the production of more cleavage products, additional morphologies spontaneously evolved from the cylindrical nanorods. Larger ball-like aggregates ultimately formed at the end of proteolysis. The uniform spherical particles, nanorods, morphological patterns evolved from nanorods, and globular aggregated microstructures were successively formed by means of co-assembly of amelogenin and its cleavage products during a comparatively slow proteolysis process. We propose that, following the C-terminal cleavage of amelogenin, co-assembly with its fragments leads to formation of nanorod structures whose properties eventually dictate the super-structural organization of enamel matrix, controlling the elongated growth of enamel apatite crystals.
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Affiliation(s)
- Xiudong Yang
- Center for Craniofacial Molecular Biology, University of Southern California, Herman Ostrow School of Dentistry, 2250 Alcazar St., Los Angeles, CA 90033, USA
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91
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Immunohistochemical expression of matrix metalloproteinases 1, 2, 7, 9, and 26 in the calcifying cystic odontogenic tumor. ACTA ACUST UNITED AC 2011; 112:609-15. [DOI: 10.1016/j.tripleo.2011.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 06/05/2011] [Accepted: 06/13/2011] [Indexed: 01/18/2023]
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92
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Lacruz RS, Smith CE, Smith SM, Hu P, Bringas P, Sahin-Tóth M, Moradian-Oldak J, Paine ML. Chymotrypsin C (caldecrin) is associated with enamel development. J Dent Res 2011; 90:1228-33. [PMID: 21828354 DOI: 10.1177/0022034511418231] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Two main proteases cleave enamel extracellular matrix proteins during amelogenesis. Matrix metalloprotease-20 (Mmp20) is the predominant enzyme expressed during the secretory stage, while kallikrein-related peptidase-4 (Klk4) is predominantly expressed during maturation. Mutations to both Mmp20 and Klk4 result in abnormal enamel phenotypes. During a recent whole-genome microarray analysis of rat incisor enamel organ cells derived from the secretory and maturation stages of amelogenesis, the serine protease chymotrypsin C (caldecrin, Ctrc) was identified as significantly up-regulated (> 11-fold) during enamel maturation. Prior reports indicate that Ctrc expression is pancreas-specific, albeit low levels were also noted in brain. We here report on the expression of Ctrc in the enamel organ. Quantitative PCR (qPCR) and Western blot analysis were used to confirm the expression of Ctrc in the developing enamel organ. The expression profile of Ctrc is similar to that of Klk4, increasing markedly during the maturation stage relative to the secretory stage, although levels of Ctrc mRNA are lower than for Klk4. The discovery of a new serine protease possibly involved in enamel development has important implications for our understanding of the factors that regulate enamel biomineralization.
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Affiliation(s)
- R S Lacruz
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, USA.
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93
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Le Norcy E, Kwak SY, Wiedemann-Bidlack FB, Beniash E, Yamakoshi Y, Simmer JP, Margolis HC. Potential role of the amelogenin N-terminus in the regulation of calcium phosphate formation in vitro. Cells Tissues Organs 2011; 194:188-93. [PMID: 21576914 DOI: 10.1159/000324827] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
N-terminal and C-terminal (CT) domains of amelogenin have been shown to be essential for proper enamel formation. Recent studies have also suggested that although the C-terminus plays an apparent role in protein-mineral interactions, other amelogenin structural domains are involved. The objective was to explore the role of the amelogenin N-terminus in the regulation of calcium phosphate formation in vitro. Spontaneous mineralization studies were carried out using the phosphorylated (+P) and nonphosphorylated (-P) N-terminus of the leucine-rich amelogenin peptide (LRAP) that lacks the hydrophilic CT domain. Mineralization progress was monitored via changes in solution pH. Mineral phases formed were characterized using TEM, selected area electron diffraction, and FT-IR. In controls, amorphous calcium phosphate was initially formed and subsequently transformed to randomly oriented hydroxyapatite (HA) plate-like crystals. In contrast to the control, LRAP(+P)-CT stabilized ACP formation for >1 day, while LRAP(-P)-CT accelerated the transformation of ACP to HA but had little effect on crystal shape or orientation. In conclusion, the N-terminal domain found in LRAP, as in amelogenins, appears to have the capacity to interact with forming calcium phosphate mineral phases. Results suggest that the N-terminal domain of amelogenin may play a direct role in early stages of enamel formation.
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Affiliation(s)
- E Le Norcy
- Department of Biomineralization, The Forsyth Institute, Cambridge, Mass., USA
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94
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Simmer JP, Hu Y, Richardson AS, Bartlett JD, Hu JCC. Why does enamel in Klk4-null mice break above the dentino-enamel junction? Cells Tissues Organs 2011; 194:211-5. [PMID: 21546759 PMCID: PMC3178080 DOI: 10.1159/000324260] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The enamel layerof kallikrein 4 (Klk4)-null mice has a normal thickness and a decussating pattern of enamel rods, but it contains residual enamel proteins, is less highly mineralized, and fractures in its deepest part just above the dentino-enamel junction (DEJ). The plane of fracture is puzzling because the deepest enamel is deposited earliest and, through the action of the secretory stage enamel protease (Mmp20), is the most mature part of the enamel layer at the time of the onset of Klk4 expression. OBJECTIVES To characterize the planes of fracture in Mmp20- and Klk4-null mice and to localize Klk4 expression in developing teeth. METHODS Klk4- and Mmp20-null mice were sacrificed at 7 weeks and their mandibular incisors were characterized by scanning electron microscopy. Klk4(+/)(lac)(Z) mice were mated with Klk4(+/)(lac)(Z) mice. Offspring were genotyped by polymerase chain reaction. Klk4(+/)(+), Klk4(+/)(lac)(Z), and Klk4(lac)(Z/)(lac)(Z) (null) littermates on postnatal days 5, 8, 11, and 14 were processed for β-galactosidase histochemistry. RESULTS The enamel layer fractures at the DEJ in Mmp20-null mice, and fractures occur in enamel above the DEJ in Klk4-null mice. Klk4 is not expressed by secretory-stage ameloblasts, murine odontoblasts beneath the secretory stage, or maturation-stage ameloblasts. Klk4 is specifically expressed by transition and maturation-stage ameloblasts. CONCLUSIONS The breakage of enamel near the DEJ in Klk4-null mice is not due to a failure of odontoblasts to express Klk4, but it relates to a progressive hypomineralization of enamel with depth.
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Affiliation(s)
- James P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Mich
| | - Yuanyuan Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Mich
| | - Amelia S. Richardson
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Mich
| | - John D. Bartlett
- Department of Cytokine Biology, The Forsyth Institute, Cambridge, Mass., USA
| | - Jan C.-C. Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Mich
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95
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Ferro F, Spelat R, Falini G, Gallelli A, D'Aurizio F, Puppato E, Pandolfi M, Beltrami AP, Cesselli D, Beltrami CA, Ambesi-Impiombato FS, Curcio F. Adipose tissue-derived stem cell in vitro differentiation in a three-dimensional dental bud structure. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2299-310. [PMID: 21514442 PMCID: PMC3081158 DOI: 10.1016/j.ajpath.2011.01.055] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 01/05/2011] [Accepted: 01/10/2011] [Indexed: 01/09/2023]
Abstract
Tooth morphogenesis requires sequential and reciprocal interactions between the cranial neural crest-derived mesenchymal cells and the stomadial epithelium, which regulate tooth morphogenesis and differentiation. We show how mesenchyme-derived single stem cell populations can be induced to transdifferentiate in vitro in a structure similar to a dental bud. The presence of stem cells in the adipose tissue has been previously reported. We incubated primary cultures of human adipose tissue-derived stem cells in a dental-inducing medium and cultured the aggregates in three-dimensional conditions. Four weeks later, cells formed a three-dimensional organized structure similar to a dental bud. Expression of dental tissue-related markers was tested assaying lineage-specific mRNA and proteins by RT-PCR, immunoblot, IHC, and physical-chemical analysis. In the induction medium, cells were positive for ameloblastic and odontoblastic markers as both mRNAs and proteins. Also, cells expressed epithelial, mesenchymal, and basement membrane markers with a positional relationship similar to the physiologic dental morphogenesis. Physical-chemical analysis revealed 200-nm and 50-nm oriented hydroxyapatite crystals as displayed in vivo by enamel and dentin, respectively. In conclusion, we show that adipose tissue-derived stem cells in vitro can transdifferentiate to produce a specific three-dimensional organization and phenotype resembling a dental bud even in the absence of structural matrix or scaffold to guide the developmental process.
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Affiliation(s)
- Federico Ferro
- Department of Pathology and Experimental and Clinical Medicine, University of Udine, Udine, Italy
| | - Renza Spelat
- Department of Pathology and Experimental and Clinical Medicine, University of Udine, Udine, Italy
| | - Giuseppe Falini
- Department of Chemistry “G. Ciamican,” Alma Mater Studiorum University of Bologna, via Selmi, Bologna, Italy
| | | | | | - Elisa Puppato
- Centre of Regenerative Medicine, University of Udine, Udine, Italy
| | - Maura Pandolfi
- Centre of Regenerative Medicine, University of Udine, Udine, Italy
| | | | - Daniela Cesselli
- Centre of Regenerative Medicine, University of Udine, Udine, Italy
| | | | | | - Francesco Curcio
- Department of Pathology and Experimental and Clinical Medicine, University of Udine, Udine, Italy
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96
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Quinlan A, Murat D, Vali H, Komeili A. The HtrA/DegP family protease MamE is a bifunctional protein with roles in magnetosome protein localization and magnetite biomineralization. Mol Microbiol 2011; 80:1075-87. [PMID: 21414040 DOI: 10.1111/j.1365-2958.2011.07631.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Magnetotactic bacteria contain nanometre-sized, membrane-bound organelles, called magnetosomes, which are tasked with the biomineralization of small crystals of the iron oxide magnetite allowing the organism to use geomagnetic field lines for navigation. A key player in this process is the HtrA/DegP family protease MamE. In its absence, Magnetospirillum magneticum str AMB-1 is able to form magnetosome membranes but not magnetite crystals, a defect previously linked to the mislocalization of magnetosome proteins. In this work we use a directed genetic approach to find that MamE, and another predicted magnetosome-associated protease, MamO, likely function as proteases in vivo. However, as opposed to the complete loss of mamE where no biomineralization is observed, the protease-deficient variant of this protein still supports the initiation and formation of small, 20 nm-sized crystals of magnetite, too small to hold a permanent magnetic dipole moment. This analysis also reveals that MamE is a bifunctional protein with a protease-independent role in magnetosome protein localization and a protease-dependent role in maturation of small magnetite crystals. Together, these results imply the existence of a previously unrecognized 'checkpoint' in biomineralization where MamE moderates the completion of magnetite formation and thus committal to magneto-aerotaxis as the organism's dominant mode of navigating the environment.
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Affiliation(s)
- Anna Quinlan
- Department of Molecular and Cell Biology, University of California Berkeley, 111 Koshland Hall, Berkeley, CA 94720, USA
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97
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Paine ML, Lei Y, Luo W, Snead ML. Perturbed Amelogenin Protein Self-assembly Alters Nanosphere Properties Resulting in Defective Enamel Formation. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-823-w6.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractDental enamel is a unique composite bioceramic material that is the hardest tissue in the vertebrate body, containing long-, thin-crystallites of substituted hydroxyapatite. Enamel functions under immense loads in a bacterial-laden environment, and generally without catastrophic failure over a lifetime for the organism. Unlike all other biogenerated hard tissues of mesodermal origin, such as bone and dentin, enamel is produced by ectoderm-derived cells called ameloblasts. Recent investigations on the formation of enamel using cell and molecular approaches have been coupled to biomechanical investigations at the nanoscale and mesoscale levels. For amelogenin, the principle protein of forming enamel, two domains have been identified that are required for the proper assembly of multimeric units of amelogenin to form nanospheres. One domain is at the amino-terminus and the other domain in the carboxyl-terminal region. Amelogenin nanospheres are believed to influence the hydroxyapatite crystal habit. Both the yeast two-hybrid assay and surface plasmon resonance have been used to examine the assembly properties of engineered amelogenin proteins. Amelogenin protein was engineered using recombinant DNA techniques to contain deletions to either of the two self-assembly domains. Amelogenin protein was also engineered to contain single amino-acid mutations/substitutions in the amino-terminal self-assembly domain; and these amino-acid changes are based upon point mutations observed in humans affected with a hereditary disturbance of enamel formation. All of these alterations reveal significant defects in amelogenin self-assembly into nanospheres in vitro. Transgenic animals containing these same amelogenin deletions illustrate the importance of a physiologically correct bio-fabrication of the enamel protein extracellular matrix to allow for the organization of the enamel prismatic structure.
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98
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Gomes JR, Omar NF, dos Santos Neves J, Narvaes EAO, Novaes PD. Immunolocalization and activity of the MMP-9 and MMP-2 in odontogenic region of the rat incisor tooth after post shortening procedure. J Mol Histol 2011; 42:153-9. [PMID: 21308405 DOI: 10.1007/s10735-011-9318-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Accepted: 01/26/2011] [Indexed: 11/28/2022]
Abstract
MMP-9 and MMP-2 are metalloproteinases which degrade the denatured collagen fibers. However, there is no report about roles of these MMPs in the odontogenic region of the adult rat incisor tooth under different eruption conditions. Male Wistar rats were divided in a normofunctional group (NF) in which their lower teeth remained in a normal eruption. In a hypofunctional group (HP) rats underwent shortening of their lower left incisor tooth every 2 days during 12 days. The eruption rate as well as the expression and activities of MMP-9 and MMP-2 were evaluated using imunohistochemistry and zymography. Although the shortening increased the eruption rate, no changes in the MMP-9 and MMP-2 were observed. We conclude that in adult rats, in opposite to development of tooth, the MMP-9 and MMP-2 present in the odontogenic region does not seem to play a direct role in the remodeling matrix, even after post-shortening procedures which to lead an acceleration of the eruption process in the incisor.
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Affiliation(s)
- Jose Rosa Gomes
- Departamento de Biologia Estrutural Molecular e Genética, UEPG, Avenue Carlos Cavalcanti, 4748, Ponta Grossa, PR, 84030-900, Brazil.
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99
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Haruyama N, Hatakeyama J, Moriyama K, Kulkarni AB. Amelogenins: Multi-Functional Enamel Matrix Proteins and Their Binding Partners. J Oral Biosci 2011. [DOI: 10.1016/s1349-0079(11)80009-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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100
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Davaadorj P, Tokuyama R, Ide S, Tadokoro S, Kudoh K, Satomura K. Possible involvement of maspin in tooth development. Histochem Cell Biol 2010; 134:603-14. [PMID: 21069375 DOI: 10.1007/s00418-010-0756-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2010] [Indexed: 10/18/2022]
Abstract
Maspin is a 42 kDa serine protease inhibitor that possesses tumor suppressive and anti-angiogenic activities. Despite of a huge amount of data concerning the expression pattern of maspin in various tissues and its relevance to the biological properties of a variety of human cancer cells, little is known on the maspin expression in skeletal and tooth tissues. Recently, we reported that maspin may play an important role in extracellular matrix formation in bone by enhancing the accumulation of latent TGF-β in the extracellular matrix. This study was performed to elucidate the possible role of maspin in tooth development. First, an immunohistochemical analysis for human tooth germs at the late bell stage showed the expression of maspin by active ameloblasts and odontoblasts that were forming enamel and dentin, respectively. During rat tooth development, maspin expression was observed for the first time in inner and outer enamel epithelial cells and dental papilla cells at early bell stage. The neutralizing anti-maspin antibody inhibited the proper dental tissue formation in organ cultures of mandibular first molars obtained from 21-day-old rat embryos. In addition, the proliferation of HAT-7 cells, a rat odontogenic epithelial cell line, and human dental papilla cells were suppressed in a dose-dependent manner with anti-maspin antibody. Moreover, RT-PCR analysis showed that the expression of mRNA for tooth-related genes including dentin matrix protein 1, dentin sialophosphoprotein and osteopontin in human dental papilla cells was inhibited when treated with anti-maspin antibody. These findings suggest that maspin expressed in ameloblasts and odontoblasts plays an important physiological role in tooth development through the regulation of matrix formation in dental tissues.
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Affiliation(s)
- Purevsuren Davaadorj
- Department of Oral and Maxillofacial Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
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