1
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Andras NL, Mohamed FF, Chu EY, Foster BL. Between a rock and a hard place: Regulation of mineralization in the periodontium. Genesis 2022; 60:e23474. [PMID: 35460154 PMCID: PMC9492628 DOI: 10.1002/dvg.23474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 12/30/2022]
Abstract
The periodontium supports and attaches teeth via mineralized and nonmineralized tissues. It consists of two, unique mineralized tissues, cementum and alveolar bone. In between these tissues, lies an unmineralized, fibrous periodontal ligament (PDL), which distributes occlusal forces, nourishes and invests teeth, and harbors progenitor cells for dentoalveolar repair. Many unanswered questions remain regarding periodontal biology. This review will focus on recent research providing insights into one enduring mystery: the precise regulation of the hard-soft tissue borders in the periodontium which define the interfaces of the cementum-PDL-alveolar bone structure. We will focus on advances in understanding the molecular mechanisms that maintain the unmineralized PDL "between a rock and a hard place" by regulating the mineralization of cementum and alveolar bone.
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Affiliation(s)
- Natalie L. Andras
- Biosciences Division, College of DentistryThe Ohio State UniversityColumbusOhioUSA
| | - Fatma F. Mohamed
- Biosciences Division, College of DentistryThe Ohio State UniversityColumbusOhioUSA
| | - Emily Y. Chu
- Division of Operative Dentistry, Department of General Dentistry, School of DentistryUniversity of MarylandBaltimoreMarylandUSA
| | - Brian L. Foster
- Biosciences Division, College of DentistryThe Ohio State UniversityColumbusOhioUSA
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2
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Surface and Structural Studies of Age-Related Changes in Dental Enamel: An Animal Model. MATERIALS 2022; 15:ma15113993. [PMID: 35683290 PMCID: PMC9182525 DOI: 10.3390/ma15113993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/26/2022] [Accepted: 06/01/2022] [Indexed: 01/28/2023]
Abstract
In the animal kingdom, continuously erupting incisors provided an attractive model for studying the enamel matrix and mineral composition of teeth during development. Enamel, the hardest mineral tissue in the vertebrates, is a tissue sensitive to external conditions, reflecting various disturbances in its structure. The developing dental enamel was monitored in a series of incisor samples extending the first four weeks of postnatal life in the spiny mouse. The age-dependent changes in enamel surface morphology in the micrometre and nanometre-scale and a qualitative assessment of its mechanical features were examined by applying scanning electron microscopy (SEM) and atomic force microscopy (AFM). At the same time, structural studies using XRD and vibrational spectroscopy made it possible to assess crystallinity and carbonate content in enamel mineral composition. Finally, a model for predicting the maturation based on chemical composition and structural factors was constructed using artificial neural networks (ANNs). The research presented here can extend the existing knowledge by proposing a pattern of enamel development that could be used as a comparative material in environmental, nutritional, and pharmaceutical research.
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3
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Zhang H, Chavez MB, Kolli TN, Tan MH, Fong H, Chu EY, Li Y, Ren X, Watanabe K, Kim DG, Foster BL. Dentoalveolar Defects in the Hyp Mouse Model of X-linked Hypophosphatemia. J Dent Res 2020; 99:419-428. [PMID: 31977267 DOI: 10.1177/0022034520901719] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mutations in PHEX cause X-linked hypophosphatemia (XLH), a form of hypophosphatemic rickets. Hyp (Phex mutant) mice recapitulate the XLH phenotype. Dental disorders are prevalent in individuals with XLH; however, underlying dentoalveolar defects remain incompletely understood. We analyzed Hyp mouse dentoalveolar defects at 42 and 90 d postnatal to comparatively define effects of XLH on dental formation and function. Phex mRNA was expressed by odontoblasts (dentin), osteocytes (bone), and cementocytes (cellular cementum) in wild-type (WT) mice. Enamel density was unaffected, though enamel volume was significantly reduced in Hyp mice. Dentin defects in Hyp molars were indicated histologically by wide predentin, thin dentin, and extensive interglobular dentin, confirming micro-computed tomography (micro-CT) findings of reduced dentin volume and density. Acellular cementum was thin and showed periodontal ligament detachment. Mechanical testing indicated dramatically altered periodontal mechanical properties in Hyp versus WT mice. Hyp mandibles demonstrated expanded alveolar bone with accumulation of osteoid, and micro-CT confirmed decreased bone volume fraction and alveolar bone density. Cellular cementum area was significantly increased in Hyp versus WT molars owing to accumulation of hypomineralized cementoid. Histology, scanning electron microscopy, and nanoindentation revealed hypomineralized "halos" surrounding Hyp cementocyte and osteocyte lacunae. Three-dimensional micro-CT analyses confirmed larger cementocyte/osteocyte lacunae and significantly reduced perilacunar mineral density. While long bone and alveolar bone osteocytes in Hyp mice overexpressed fibroblast growth factor 23 (Fgf23), its expression in molars was much lower, with cementocyte Fgf23 expression particularly low. Expression and distribution of other selected markers were disturbed in Hyp versus WT long bone, alveolar bone, and cementum, including osteocyte/cementocyte marker dentin matrix protein 1 (Dmp1). This study reports for the first time a quantitative analysis of the Hyp mouse dentoalveolar phenotype, including all mineralized tissues. Novel insights into cellular cementum provide evidence for a role for cementocytes in perilacunar mineralization and cementum biology.
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Affiliation(s)
- H Zhang
- Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, USA
| | - M B Chavez
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - T N Kolli
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - M H Tan
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - H Fong
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - E Y Chu
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Y Li
- Department of Oral Maxillofacial Surgery, West China School of Stomatology, Sichuan University, Chengdu, China
| | - X Ren
- Department of Periodontics, School of Stomatology, Shanxi Medical University, Taiyuan, China
| | - K Watanabe
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - D G Kim
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - B L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
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4
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Wu Y, Yuan X, Perez KC, Hyman S, Wang L, Pellegrini G, Salmon B, Bellido T, Helms JA. Aberrantly elevated Wnt signaling is responsible for cementum overgrowth and dental ankylosis. Bone 2019; 122:176-183. [PMID: 30408613 PMCID: PMC6559382 DOI: 10.1016/j.bone.2018.10.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/10/2018] [Accepted: 10/23/2018] [Indexed: 02/05/2023]
Abstract
Vertebrate teeth are attached to the jawbones using a variety of methods but in mammals, a fibrous connection is the norm. This fibrous periodontal ligament (PDL) allows teeth to move in the jawbones in response to natural eruptive forces, mastication, and orthodontic tooth movement. In some disease states the PDL either calcifies or is replaced by a mineralized tissue and the result is ankylosis, where the tooth is fused to the alveolar bone. To understand how the PDL maintains this fibrous state, we examined a strain of mice in which tooth movement is arrested. DaβcatOt mice express a stabilized form of β-catenin in DMP1-positive alveolar bone osteocytes and cementocytes, which results in elevated Wnt signaling throughout the periodontium. As a consequence, there is an accrual of massive amounts of cellular cementum and alveolar bone, the PDL itself calcifies and teeth become ankylosed. These data suggest that to maintain its fibrous nature, Wnt signaling must normally be repressed in the PDL space.
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Affiliation(s)
- Yan Wu
- Orthodontic Department, Stomatology Hospital of Chongqing Medical University, Chongqing Key Laboratory of Oral Disease and Biomedical Sciences, Chongqing Municipal Key Laboratory, Chongqing 401147, China; Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Xue Yuan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Kristy C Perez
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Sydnee Hyman
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Liao Wang
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Gretel Pellegrini
- Department of Anatomy and Cell Biology, Department of Medicine, Division of Endocrinology, Indiana University School of Medicine and Roudebush Veterans Administration Medical Center, Indianapolis, IN 46022, USA
| | - Benjamin Salmon
- Paris Descartes University - Sorbonne Paris Cité, EA 2496 - Orofacial Pathologies, Imaging and Biotherapies Lab and Dental Medicine Department, Bretonneau Hospital, HUPNVS, AP-HP, Paris, France
| | - Teresita Bellido
- Department of Anatomy and Cell Biology, Department of Medicine, Division of Endocrinology, Indiana University School of Medicine and Roudebush Veterans Administration Medical Center, Indianapolis, IN 46022, USA
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA.
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Yilmaz ED, Koldehoff J, Schneider GA. On the systematic documentation of the structural characteristics of bovine enamel: A critic to the protein sheath concept. Dent Mater 2018; 34:1518-1530. [DOI: 10.1016/j.dental.2018.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 05/24/2018] [Accepted: 06/07/2018] [Indexed: 11/28/2022]
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Foster BL, Ao M, Salmon CR, Chavez MB, Kolli TN, Tran AB, Chu EY, Kantovitz KR, Yadav M, Narisawa S, Millán JL, Nociti FH, Somerman MJ. Osteopontin regulates dentin and alveolar bone development and mineralization. Bone 2018; 107:196-207. [PMID: 29313816 PMCID: PMC5803363 DOI: 10.1016/j.bone.2017.12.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 11/09/2017] [Accepted: 12/03/2017] [Indexed: 01/09/2023]
Abstract
The periodontal complex is essential for tooth attachment and function and includes the mineralized tissues, cementum and alveolar bone, separated by the unmineralized periodontal ligament (PDL). To gain insights into factors regulating cementum-PDL and bone-PDL borders and protecting against ectopic calcification within the PDL, we employed a proteomic approach to analyze PDL tissue from progressive ankylosis knock-out (Ank-/-) mice, featuring reduced PPi, rapid cementogenesis, and excessive acellular cementum. Using this approach, we identified the matrix protein osteopontin (Spp1/OPN) as an elevated factor of interest in Ank-/- mouse molar PDL. We studied the role of OPN in dental and periodontal development and function. During tooth development in wild-type (WT) mice, Spp1 mRNA was transiently expressed by cementoblasts and strongly by alveolar bone osteoblasts. Developmental analysis from 14 to 240days postnatal (dpn) indicated normal histological structures in Spp1-/- comparable to WT control mice. Microcomputed tomography (micro-CT) analysis at 30 and 90dpn revealed significantly increased volumes and tissue mineral densities of Spp1-/- mouse dentin and alveolar bone, while pulp and PDL volumes were decreased and tissue densities were increased. However, acellular cementum growth was unaltered in Spp1-/- mice. Quantitative PCR of periodontal-derived mRNA failed to identify potential local compensators influencing cementum in Spp1-/- vs. WT mice at 26dpn. We genetically deleted Spp1 on the Ank-/- mouse background to determine whether increased Spp1/OPN was regulating periodontal tissues when the PDL space is challenged by hypercementosis in Ank-/- mice. Ank-/-; Spp1-/- double deficient mice did not exhibit greater hypercementosis than that in Ank-/- mice. Based on these data, we conclude that OPN has a non-redundant role regulating formation and mineralization of dentin and bone, influences tissue properties of PDL and pulp, but does not control acellular cementum apposition. These findings may inform therapies targeted at controlling soft tissue calcification.
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Affiliation(s)
- B L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA.
| | - M Ao
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - C R Salmon
- Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, University of Campinas, São Paulo, Brazil
| | - M B Chavez
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - T N Kolli
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - A B Tran
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - E Y Chu
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - K R Kantovitz
- Department of Dental Materials, São Leopoldo Mandic Research Center, Campinas, São Paulo, Brazil
| | - M Yadav
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Research Institute, La Jolla, CA, USA
| | - S Narisawa
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Research Institute, La Jolla, CA, USA
| | - J L Millán
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Research Institute, La Jolla, CA, USA
| | - F H Nociti
- Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, University of Campinas, São Paulo, Brazil
| | - M J Somerman
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
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Martin K, Nathwani S, Bunyan R. Craniometaphyseal Dysplasia: A review and novel oral manifestation. J Oral Biol Craniofac Res 2017; 7:134-136. [PMID: 28706789 DOI: 10.1016/j.jobcr.2017.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 04/25/2017] [Indexed: 01/26/2023] Open
Abstract
Craniometaphyseal Dysplasia (CMD) is a sclerosing osseous dysplasia characterised by hyperostosis of craniofacial and long bones, resulting in distortion and cranial nerve palsies. We present a case report on the management of a 63 year old female with Craniometaphyseal Dysplasia. This report describes an additional clinical manifestation of hypercementosis, which although well recognised in other sclerosing osseous dysplasias, is not reported in the literature for Craniometaphyseal Dysplasia. We discuss established in vivo studies in mice which link the genetic mutations found in Craniometaphyseal Dysplasia to hypercementosis, and how this report describes the same manifestation in humans. This novel finding can aid the clinician in the management of patients with Craniometaphyseal Dysplasia, and complications that can arise in dentoalveolar surgery.
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Affiliation(s)
- K Martin
- Department of Oral and Maxillofacial Surgery, Luton and Dunstable University Hospital, Lewsey Road, Luton, LU4 0DZ, United Kingdom
| | - S Nathwani
- Department of Oral and Maxillofacial Surgery, Luton and Dunstable University Hospital, Lewsey Road, Luton, LU4 0DZ, United Kingdom
| | - R Bunyan
- Department of Oral and Maxillofacial Surgery, Luton and Dunstable University Hospital, Lewsey Road, Luton, LU4 0DZ, United Kingdom
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Koehne T, Jeschke A, Petermann F, Seitz S, Neven M, Peters S, Luther J, Schweizer M, Schinke T, Kahl-Nieke B, Amling M, David JP. Rsk2, the Kinase Mutated in Coffin-Lowry Syndrome, Controls Cementum Formation. J Dent Res 2016; 95:752-60. [PMID: 26927527 DOI: 10.1177/0022034516634329] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The ribosomal S6 kinase RSK2 is essential for osteoblast function, and inactivating mutations of RSK2 cause osteopenia in humans with Coffin-Lowry syndrome (CLS). Alveolar bone loss and premature tooth exfoliation are also consistently reported symptoms in CLS patients; however, the pathophysiologic mechanisms are unclear. Therefore, aiming to identify the functional relevance of Rsk2 for tooth development, we analyzed Rsk2-deficient mice. Here, we show that Rsk2 is a critical regulator of cementoblast function. Immunohistochemistry, histology, micro-computed tomography imaging, quantitative backscattered electron imaging, and in vitro assays revealed that Rsk2 is activated in cementoblasts and is necessary for proper acellular cementum formation. Cementum hypoplasia that is observed in Rsk2-deficient mice causes detachment and disorganization of the periodontal ligament and was associated with significant alveolar bone loss with age. Moreover, Rsk2-deficient mice display hypomineralization of cellular cementum with accumulation of nonmineralized cementoid. In agreement, treatment of the cementoblast cell line OCCM-30 with a Rsk inhibitor reduces formation of mineralization nodules and decreases the expression of cementum markers. Western blot analyses based on antibodies against Rsk1, Rsk2, and an activated form of the 2 kinases confirmed that Rsk2 is expressed and activated in differentiating OCCM-30 cells. To discriminate between periodontal bone loss and systemic bone loss, we additionally crossed Rsk2-deficient mice with transgenic mice overexpressing the osteoanabolic transcription factor Fra1. Fra1 overexpression clearly increases systemic bone volume in Rsk2-deficient mice but does not protect from alveolar bone loss. Our results indicate that cell autonomous cementum defects are causing early tooth loss in CLS patients. Moreover, we identify Rsk2 as a nonredundant regulator of cementum homeostasis, alveolar bone maintenance, and periodontal health, with all these features being independent of Rsk2 function in systemic bone formation.
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Affiliation(s)
- T Koehne
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany Department of Orthodontics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - A Jeschke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - F Petermann
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - S Seitz
- Department of Orthopaedics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - M Neven
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - S Peters
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - J Luther
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - M Schweizer
- Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - T Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - B Kahl-Nieke
- Department of Orthodontics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - M Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - J-P David
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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9
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Counter-regulatory phosphatases TNAP and NPP1 temporally regulate tooth root cementogenesis. Int J Oral Sci 2015; 7:27-41. [PMID: 25504209 PMCID: PMC4817535 DOI: 10.1038/ijos.2014.62] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2014] [Indexed: 12/29/2022] Open
Abstract
Cementum is critical for anchoring the insertion of periodontal ligament fibers to the tooth root. Several aspects of cementogenesis remain unclear, including differences between acellular cementum and cellular cementum, and between cementum and bone. Biomineralization is regulated by the ratio of inorganic phosphate (Pi) to mineral inhibitor pyrophosphate (PPi), where local Pi and PPi concentrations are controlled by phosphatases including tissue-nonspecific alkaline phosphatase (TNAP) and ectonucleotide pyrophosphatase/phosphodiesterase 1 (NPP1). The focus of this study was to define the roles of these phosphatases in cementogenesis. TNAP was associated with earliest cementoblasts near forming acellular and cellular cementum. With loss of TNAP in the Alpl null mouse, acellular cementum was inhibited, while cellular cementum production increased, albeit as hypomineralized cementoid. In contrast, NPP1 was detected in cementoblasts after acellular cementum formation, and at low levels around cellular cementum. Loss of NPP1 in the Enpp1 null mouse increased acellular cementum, with little effect on cellular cementum. Developmental patterns were recapitulated in a mouse model for acellular cementum regeneration, with early TNAP expression and later NPP1 expression. In vitro, cementoblasts expressed Alpl gene/protein early, whereas Enpp1 gene/protein expression was significantly induced only under mineralization conditions. These patterns were confirmed in human teeth, including widespread TNAP, and NPP1 restricted to cementoblasts lining acellular cementum. These studies suggest that early TNAP expression creates a low PPi environment promoting acellular cementum initiation, while later NPP1 expression increases PPi, restricting acellular cementum apposition. Alterations in PPi have little effect on cellular cementum formation, though matrix mineralization is affected.
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Sundaram S, Ramaseshan R, Dash S, Rao SR. Evaluation of the nanostructure of cervical third cementum in health and chronic periodontitis: An in vitro study. J Indian Soc Periodontol 2014; 18:560-6. [PMID: 25425815 PMCID: PMC4239743 DOI: 10.4103/0972-124x.142440] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 02/10/2014] [Indexed: 12/23/2022] Open
Abstract
Background: During the progression of periodontal disease, the cementum undergoes alterations in its structure and composition. Understanding the nanostructure of cementum, in terms of its mechanical properties, will provide an insight into the milieu that periodontal ligament cells encounter in health and chronic periodontitis. This study aims to analyze the nanomechanical properties of the cervical third of the cementum (transverse section) in health and chronic periodontitis. Materials and Methods: Twenty teeth (10 healthy and 10 periodontally diseased) were collected and the nanomechanical properties of the transverse section of the cervical third cementum were evaluated with depth-sensing nanoindentation technique under dry conditions. A total of 100 nanoindentations were performed to analyze the modulus of elasticity and hardness of cervical third of the cementum. Results: The nanomechanical properties of the healthy cervical third cementum sections were significantly higher (P < 0.05) (hardness: 0.720 ± 0.305 GPa; modulus: 15.420 ± 3.902 GPa) than the diseased cementum section (hardness: 0.422 ± 0.157 GPa; modulus: 11.056 ± 3.434 GPa). Conclusion: The results of our study indicate that the hardness and modulus of elasticity of the cervical third cementum decreases significantly in chronic periodontitis.
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Affiliation(s)
- Subramoniam Sundaram
- Department of Periodontics, Faculty of Dental Sciences, Sri Ramachandra University, Porur, Chennai, India
| | - Rajagopalan Ramaseshan
- Surface and Nanoscience Division, Thin Films and Coatings Section, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India
| | - Sitaram Dash
- Surface and Nanoscience Division, Thin Films and Coatings Section, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India
| | - Suresh Ranga Rao
- Department of Periodontics, Faculty of Dental Sciences, Sri Ramachandra University, Porur, Chennai, India
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11
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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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Xu HG, Zhang W, Zheng Q, Yu YF, Deng LF, Wang H, Liu P, Zhang M. Investigating conversion of endplate chondrocytes induced by intermittent cyclic mechanical unconfined compression in three-dimensional cultures. Eur J Histochem 2014; 58:2415. [PMID: 25308847 PMCID: PMC4194395 DOI: 10.4081/ejh.2014.2415] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/10/2014] [Accepted: 06/12/2014] [Indexed: 12/25/2022] Open
Abstract
Mechanical stimulation is known to regulate the calcification of endplate chondrocytes. The Ank protein has a strong influence on anti-calcification by transports intracellular inorganic pyrophosphate (PPi) to the extracellular matrix. It is known that TGF-β1 is able to induce Ank gene expression and protect chondrocyte calcification. Intermittent cyclic mechanical tension (ICMT) could induce calcification of endplate chondrocytes by decrease the expression of Ank gene. In this study, we investigated the relation of intermittent cyclic mechanical unconfined compression (ICMC) and Ank gene expression. We found that ICMC decreased the Ank gene expression in the endplate chondrocytes, and there was an decreased in the TGF-β1 expression after ICMC stimulation. The Ank gene expression significantly increased when treated by transforming growth factor alpha 1 (TGF-β1) in a dose-dependent manner and decreased when treated by SB431542 (ALK inhibitor) in a dose-dependent manner. Our results implicate that ICMC-induced downregulation of Ank gene expression may be regulated by TGF-β1 in end-plate chondrocytes.
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Abstract
Teeth are mineralized organs composed of three unique hard tissues, enamel, dentin, and cementum, and supported by the surrounding alveolar bone. Although odontogenesis differs from osteogenesis in several respects, tooth mineralization is susceptible to similar developmental failures as bone. Here we discuss conditions fitting under the umbrella of rickets, which traditionally referred to skeletal disease associated with vitamin D deficiency but has been more recently expanded to include newly identified factors involved in endocrine regulation of vitamin D, phosphate, and calcium, including phosphate-regulating endopeptidase homolog, X-linked, fibroblast growth factor 23, and dentin matrix protein 1. Systemic mineral metabolism intersects with local regulation of mineralization, and factors including tissue nonspecific alkaline phosphatase are necessary for proper mineralization, where rickets can result from loss of activity of tissue nonspecific alkaline phosphatase. Individuals suffering from rickets often bear the additional burden of a defective dentition, and transgenic mouse models have aided in understanding the nature and mechanisms involved in tooth defects, which may or may not parallel rachitic bone defects. This report reviews dental effects of the range of rachitic disorders, including discussion of etiologies of hereditary forms of rickets, a survey of resulting bone and tooth mineralization disorders, and a discussion of mechanisms, known and hypothesized, involved in the observed dental pathologies. Descriptions of human pathology are augmented by analysis of transgenic mouse models, and new interpretations are brought to bear on questions of how teeth are affected under conditions of rickets. In short, the rachitic tooth will be revealed.
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Affiliation(s)
- Brian L Foster
- National Institute for Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892
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Foster BL, Nagatomo KJ, Nociti FH, Fong H, Dunn D, Tran AB, Wang W, Narisawa S, Millán JL, Somerman MJ. Central role of pyrophosphate in acellular cementum formation. PLoS One 2012; 7:e38393. [PMID: 22675556 PMCID: PMC3366957 DOI: 10.1371/journal.pone.0038393] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 05/09/2012] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Inorganic pyrophosphate (PP(i)) is a physiologic inhibitor of hydroxyapatite mineral precipitation involved in regulating mineralized tissue development and pathologic calcification. Local levels of PP(i) are controlled by antagonistic functions of factors that decrease PP(i) and promote mineralization (tissue-nonspecific alkaline phosphatase, Alpl/TNAP), and those that increase local PP(i) and restrict mineralization (progressive ankylosis protein, ANK; ectonucleotide pyrophosphatase phosphodiesterase-1, NPP1). The cementum enveloping the tooth root is essential for tooth function by providing attachment to the surrounding bone via the nonmineralized periodontal ligament. At present, the developmental regulation of cementum remains poorly understood, hampering efforts for regeneration. To elucidate the role of PP(i) in cementum formation, we analyzed root development in knock-out ((-/-)) mice featuring PP(i) dysregulation. RESULTS Excess PP(i) in the Alpl(-/-) mouse inhibited cementum formation, causing root detachment consistent with premature tooth loss in the human condition hypophosphatasia, though cementoblast phenotype was unperturbed. Deficient PP(i) in both Ank and Enpp1(-/-) mice significantly increased cementum apposition and overall thickness more than 12-fold vs. controls, while dentin and cellular cementum were unaltered. Though PP(i) regulators are widely expressed, cementoblasts selectively expressed greater ANK and NPP1 along the root surface, and dramatically increased ANK or NPP1 in models of reduced PP(i) output, in compensatory fashion. In vitro mechanistic studies confirmed that under low PP(i) mineralizing conditions, cementoblasts increased Ank (5-fold) and Enpp1 (20-fold), while increasing PP(i) inhibited mineralization and associated increases in Ank and Enpp1 mRNA. CONCLUSIONS Results from these studies demonstrate a novel developmental regulation of acellular cementum, wherein cementoblasts tune cementogenesis by modulating local levels of PP(i), directing and regulating mineral apposition. These findings underscore developmental differences in acellular versus cellular cementum, and suggest new approaches for cementum regeneration.
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Affiliation(s)
- Brian L Foster
- Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
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15
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Rodrigues TL, Foster BL, Silverio KG, Martins L, Casati MZ, Sallum EA, Somerman MJ, Nociti FH. Correction of hypophosphatasia-associated mineralization deficiencies in vitro by phosphate/pyrophosphate modulation in periodontal ligament cells. J Periodontol 2011; 83:653-63. [PMID: 22014174 DOI: 10.1902/jop.2011.110310] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Mutations in the liver/bone/kidney alkaline phosphatase (ALPL) gene in hypophosphatasia (HPP) reduce the function of tissue non-specific alkaline phosphatase (ALP), resulting in increased pyrophosphate (PP(i)) and a severe deficiency in acellular cementum. We hypothesize that exogenous phosphate (P(i)) would rescue the in vitro mineralization capacity of periodontal ligament (PDL) cells harvested from HPP-diagnosed patients, by correcting the P(i)/PP(i) ratio and modulating expression of genes involved with P(i)/PP(i) metabolism. METHODS Ex vivo and in vitro analyses were used to identify mechanisms involved in HPP-associated PDL/tooth root deficiencies. Constitutive expression of PP(i)-associated genes was contrasted in PDL versus pulp tissues obtained from healthy individuals. Primary PDL cell cultures from patients with HPP (monozygotic twin males) were established to assay ALP activity, in vitro mineralization, and gene expression. Exogenous P(i) was provided to correct the P(i)/PP(i) ratio. RESULTS PDL tissues obtained from healthy individuals featured higher basal expression of key PP(i) regulators, genes ALPL, progressive ankylosis protein (ANKH), and ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), versus paired pulp tissues. A novel ALPL mutation was identified in the twin patients with HPP enrolled in this study. Compared to controls, HPP-PDL cells exhibited significantly reduced ALP and mineralizing capacity, which were rescued by addition of 1 mM P(i). Dysregulated expression of PP(i) regulatory genes ALPL, ANKH, and ENPP1 was also corrected by adding P(i), although other matrix markers evaluated in our study remained downregulated. CONCLUSION These findings underscore the importance of controlling the P(i)/PP(i) ratio toward development of a functional periodontal apparatus and support P(i)/PP(i) imbalance as the etiology of HPP-associated cementum defects.
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Affiliation(s)
- Thaisângela L Rodrigues
- Department of Prosthodontics and Periodontics, Campinas State University, Piracicaba, São Paulo, Brazil
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Rodrigues TL, Nagatomo KJ, Foster BL, Nociti FH, Somerman MJ. Modulation of phosphate/pyrophosphate metabolism to regenerate the periodontium: a novel in vivo approach. J Periodontol 2011; 82:1757-66. [PMID: 21488756 DOI: 10.1902/jop.2011.110103] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND The developing periodontium is sensitive to local levels of inorganic phosphate (P(i)) and inorganic pyrophosphate (PP(i)) as demonstrated by cementum phenotypes resulting from the loss of function of protein regulators of P(i)/PP(i) homeostasis. The progressive ankylosis protein (ANK) regulates the transport of PP(i), and progressive ankylosis gene (Ank) and knock-out (KO) mice feature a rapidly forming and thick cementum. We hypothesized that, besides affecting cementum formation, decreased extracellular PP(i) levels in Ank KO mice would also impact cementum regeneration. METHODS Periodontal fenestration defects (approximately 2 mm in length, 1 mm in width, and 0.5 mm in depth) were created on buccal aspects of mandibular molars in Ank KO and wild-type (WT) mice. Mandibles were harvested at 15 and 30 days post-surgery for histology, histomorphometry, evaluation of in vivo fluorochrome labeling, and immunohistochemistry (IHC) for proteins including bone sialoprotein (BSP), osteopontin (OPN), dentin matrix protein 1 (DMP1), and ectonucleotide pyrophosphatase/phosphodiesterase 1 (NPP1). RESULTS A greater amount of new cementum was observed in Ank KO mice at 15 and 30 days post-surgery (P <0.05), which was confirmed by fluorochrome labeling showing a higher new cementum appositional activity in defect areas in Ank KO mice versus controls. At days 15 and 30 during healing, regenerating cementum and associated cells in Ank KO samples recapitulated expression patterns mapped during development, including limited BSP and positive OPN and DMP1 in the cementum matrix as well as elevated NPP1 in cementoblasts. CONCLUSIONS Within the limits of the study, these findings suggest that reduced local levels of PP(i) could promote increased cementum regeneration. Therefore, the local modulation of P(i)/PP(i) may be a potential therapeutic approach for achieving improved cementum regeneration.
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Affiliation(s)
- Thaisângela L Rodrigues
- Department of Prosthodontics and Periodontics, Division of Periodontics, School of Dentistry, Campinas State University, Piracicaba, SP, Brazil
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Foster BL, Nagatomo KJ, Bamashmous SO, Tompkins KA, Fong H, Dunn D, Chu EY, Guenther C, Kingsley DM, Rutherford RB, Somerman MJ. The progressive ankylosis protein regulates cementum apposition and extracellular matrix composition. Cells Tissues Organs 2011; 194:382-405. [PMID: 21389671 DOI: 10.1159/000323457] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2010] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND/AIMS Tooth root cementum is sensitive to modulation of inorganic pyrophosphate (PP(i)), an inhibitor of hydroxyapatite precipitation. Factors increasing PP(i) include progressive ankylosis protein (ANK) and ectonucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) while tissue nonspecific alkaline phosphatase hydrolyzes PP(i). Studies here aimed to define the role of ANK in root and cementum by analyzing tooth development in Ank knock-out (KO) mice versus wild type. MATERIALS AND METHODS Periodontal development in KO versus control mice was analyzed by histology, histomorphometry, immunohistochemistry, in situ hybridization, electron microscopy, and nanoindentation. Cementoblast cultures were used in vitro to provide mechanistic underpinnings for PP(i) modulation of cell function. RESULTS Over the course of root development, Ank KO cervical cementum became 8- to 12-fold thicker than control cervical cementum. Periodontal ligament width was maintained and other dentoalveolar tissues, including apical cementum, were unaltered. Cervical cementum uncharacteristically included numerous cells, from rapid cementogenesis. Ank KO increased osteopontin and dentin matrix protein 1 gene and protein expression, and markedly increased NPP1 protein expression in cementoblasts but not in other cell types. Conditional ablation of Ank in joints and periodontia confirmed a local role for ANK in cementogenesis. In vitro studies employing cementoblasts indicated that Ank and Enpp1 mRNA levels increased in step with mineral nodule formation, supporting a role for these factors in regulation of cementum matrix mineralization. CONCLUSION ANK, by modulating local PP(i), controls cervical cementum apposition and extracellular matrix. Loss of ANK created a local environment conducive to rapid cementogenesis; therefore, approaches modulating PP(i) in periodontal tissues have potential to promote cementum regeneration.
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Affiliation(s)
- B L Foster
- Department of Periodontics, University of Washington School of Dentistry, Seattle, Wash. 98195, USA.
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Material binding peptides for nanotechnology. Molecules 2011; 16:1426-51. [PMID: 21307821 PMCID: PMC6259601 DOI: 10.3390/molecules16021426] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/06/2011] [Accepted: 02/08/2011] [Indexed: 12/20/2022] Open
Abstract
Remarkable progress has been made to date in the discovery of material binding peptides and their utilization in nanotechnology, which has brought new challenges and opportunities. Nowadays phage display is a versatile tool, important for the selection of ligands for proteins and peptides. This combinatorial approach has also been adapted over the past decade to select material-specific peptides. Screening and selection of such phage displayed material binding peptides has attracted great interest, in particular because of their use in nanotechnology. Phage display selected peptides are either synthesized independently or expressed on phage coat protein. Selected phage particles are subsequently utilized in the synthesis of nanoparticles, in the assembly of nanostructures on inorganic surfaces, and oriented protein immobilization as fusion partners of proteins. In this paper, we present an overview on the research conducted on this area. In this review we not only focus on the selection process, but also on molecular binding characterization and utilization of peptides as molecular linkers, molecular assemblers and material synthesizers.
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Morava E, Kühnisch J, Drijvers JM, Robben JH, Cremers C, van Setten P, Branten A, Stumpp S, de Jong A, Voesenek K, Vermeer S, Heister A, Claahsen-van der Grinten HL, O'Neill CW, Willemsen MA, Lefeber D, Deen PMT, Kornak U, Kremer H, Wevers RA. Autosomal recessive mental retardation, deafness, ankylosis, and mild hypophosphatemia associated with a novel ANKH mutation in a consanguineous family. J Clin Endocrinol Metab 2011; 96:E189-98. [PMID: 20943778 PMCID: PMC5393418 DOI: 10.1210/jc.2010-1539] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Mutations in ANKH cause the highly divergent conditions familial chondrocalcinosis and craniometaphyseal dysplasia. The gene product ANK is supposed to regulate tissue mineralization by transporting pyrophosphate to the extracellular space. OBJECTIVE We evaluated several family members of a large consanguineous family with mental retardation, deafness, and ankylosis. We compared their skeletal, metabolic, and serological parameters to that of the autosomal recessive progressive ankylosis (ank) mouse mutant, caused by a loss-of-function mutation in the murine ortholog Ank. PARTICIPANTS The studied patients had painful small joint soft-tissue calcifications, progressive spondylarthropathy, osteopenia, mild hypophosphatemia, mixed hearing loss, and mental retardation. RESULTS After mapping the disease gene to 5p15, we identified the novel homozygous ANK missense mutation L244S in all patients. Although L244 is a highly conserved amino acid, the mutated ANK protein was detected at normal levels at the plasma membrane in primary patient fibroblasts. The phenotype was highly congruent with the autosomal recessive progressive ankylosis (ank) mouse mutant. This indicates a loss-of-function effect of the L244S mutation despite normal ANK protein expression. Interestingly, our analyses revealed that the primary step of joint degeneration is fibrosis and mineralization of articular soft tissues. Moreover, heterozygous carriers of the L244S mutation showed mild osteoarthritis without metabolic alterations, pathological calcifications, or central nervous system involvement. CONCLUSION Beyond the description of the first human progressive ankylosis phenotype, our results indicate that ANK influences articular soft tissues commonly involved in degenerative joint disorders. Furthermore, this human disorder provides the first direct evidence for a role of ANK in the central nervous system.
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Affiliation(s)
- Eva Morava
- Radboud University Nijmegen, Department of Pediatrics, Nijmegen, The Netherlands.
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