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Li S, Li S. Temperal and spatial expression of CCN1, CCN3, CCN4, CCN5 and CCN6 proteins in the developing postnatal teeth. J Cell Commun Signal 2023:10.1007/s12079-023-00758-7. [PMID: 37160590 DOI: 10.1007/s12079-023-00758-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 04/28/2023] [Indexed: 05/11/2023] Open
Abstract
CCN proteins are matricellular proteins and are important modulators of development and function of adult organs. However, there is no literature reporting the localization of CCN proteins during postnatal tooth development and the formation of periodontium. Therefore, the aim of our study was to investigate the expression of CCN1, CCN3, CCN4, CCN5 and CCN6 in the developing postnatal teeth. Wistar rats were used at postnatal (PN) 3.5, 7, 16 and 21 days and maxillas were processed for immunohistochemistry. At PN3.5 and PN7, preameloblasts (PA), secretory ameloblasts (SA), odontoblasts (OD) and dental pulp (DP) showed moderate to strong staining for CCN1, CCN4 and CCN6 respectively. CCN5 was intensely expressed in predentin, whereas CCN5 was undetectable in PA, SA, OD and DP. At PN16 and PN21, moderate to strong reaction with CCN1, CCN4 and CCN6 was evident in OD, DP, reduced enamel epithelium (REE), osteoblasts (OB) and periodontal ligament (PDL) respectively, while CCN5 was negative to weakly expressed in REE, OD, DP, OB, PDL and osteocytes (OC). Interestingly, the expression of CCN1, CCN4 and CCN6 was initially negative at PN16 but strong at PN21 in OC. Furthermore, there was no staining for CCN3 in the tissues studied. These results demonstrated that the expression pattern of CCN1, CCN4 and CCN6 is similar and inversely correlated with that of CCN3. CCN5 exhibits a unique distribution pattern. These data indicate that CCN proteins might play regulatory roles in amelogenesis, dentinogenesis, osteogenesis and PDL homeostasis.
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Affiliation(s)
- Shubo Li
- Department of Stomatology, College of Medicine and Health, Lishui University, Lishui, 323000, Zhejiang Province, China.
- Department of Stomatology, Affliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Province, China.
| | - Shufang Li
- Department of Stomatology, Affliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Province, China
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Structure and Chemical Composition of ca. 10-Million-Year-Old (Late Miocene of Western Amazon) and Present-Day Teeth of Related Species. BIOLOGY 2022; 11:biology11111636. [PMID: 36358337 PMCID: PMC9687460 DOI: 10.3390/biology11111636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/28/2022] [Accepted: 10/06/2022] [Indexed: 11/10/2022]
Abstract
Molecular information has been gathered from fossilized dental enamel, the best-preserved tissue of vertebrates. However, the association of morphological features with the possible mineral and organic information of this tissue is still poorly understood in the context of the emerging area of paleoproteomics. This study aims to compare the morphological features and chemical composition of dental enamel of extinct and extant terrestrial vertebrates of Crocodylia: Purussaurus sp. (extinct) and Melanosuchus niger (extant), and Rodentia: Neoepiblema sp. (extinct) and Hydrochoerus hydrochaeris (extant). To obtain structural and chemical data, superficial and internal enamel were analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (SEM-EDS). Organic, mineral, and water content were obtained using polarizing microscopy and microradiography on ground sections of four teeth, resulting in a higher organic volume than previously expected (up to 49%). It is observed that both modern and fossil tooth enamel exhibit the same major constituents: 36.7% Ca, 17.2% P, and 41% O, characteristic of hydroxyapatite. Additionally, 27 other elements were measured from superficial enamel by inductively coupled mass spectrometry (ICP-MS). Zinc was the most abundant microelement detected, followed by Pb, Fe, Mg, and Al. Morphological features observed include enamel rods in the rodent teeth, while incremental lines and semiprismatic enamel were observed in the alligator species. The fossil enamel was in an excellent state for microscopic analyses. Results show that all major dental enamel’s physical, chemical, and morphological features are present both in extant and extinct fossil tooth enamel (>8.5 Ma) in both taxa.
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Nogueira FCS, Neves LX, Pessoa-Lima C, Langer MC, Domont GB, Line SRP, Paes Leme AF, Gerlach RF. Ancient enamel peptides recovered from the South American Pleistocene species Notiomastodon platensis and Myocastor cf. coypus. J Proteomics 2021; 240:104187. [PMID: 33757878 DOI: 10.1016/j.jprot.2021.104187] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 03/13/2021] [Accepted: 03/17/2021] [Indexed: 10/21/2022]
Abstract
We used two fossil teeth from South American Pleistocene mammals to obtain subsuperficial acid etching samples. We employed samples from the species Notiomastodon platensis and Myocastor cf. coypus for the enamel etchings. The controls included an extant rodent (rat). After the first etching was discarded, a second 20-s etching (i.e., subsuperficial) was directly collected with a ZipTip and injected into an LTQ Orbitrap Velos for MS analysis. The peptides were identified with different software programs that used Peptide Spectrum Match (PSM) and de novo sequencing including similarity search strategies. Most of the peptides that were recovered from the enamel of the fossils belonged to enamel-specific proteins. To our knowledge, this is the first study that has described the recovery of enamel peptide molecules from extinct South American taxa, indicating that enamel peptide data from late Pleistocene fossils can be employed as an additional parameter for phylogenetic analysis, and that the sample can be obtained by a very conservative acid etching, with almost no damage to the fossils. SIGNIFICANCE: This study shows that it is possible to obtain information based on plenty of ancient peptides recovered from subsuperficial enamel of fossil teeth from South American Pleistocene. The quality of the data suggests that peptides are likely the best preserved biomolecules under certain harsh environmental conditions. The recovery procedure only lasted 20 s and was minimally destructive to the fossils. This opens a myriad of new possibilities for the study of the past.
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Affiliation(s)
- Fabio C S Nogueira
- Proteomics Unit, Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Laboratory of Proteomics/LADETEC, Federal University of Rio de Janeiro (UFRJ), RJ, Rio de Janeiro, Brazil
| | - Leandro Xavier Neves
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - Caroline Pessoa-Lima
- Department of Basic and Oral Biology, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, FORP/USP, Brazil
| | - Max Cardoso Langer
- Laboratory of Paleontology, Department of Biology, FFCLRP, University of São Paulo, FFCLRP/USP, Ribeirão Preto, SP, Brazil
| | - Gilberto B Domont
- Proteomics Unit, Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Sergio Roberto Peres Line
- Biosciences Department, Piracicaba Dental School, University of Campinas, FOP/UNICAMP, Piracicaba, SP, Brazil
| | - Adriana Franco Paes Leme
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - Raquel Fernanda Gerlach
- Department of Basic and Oral Biology, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, FORP/USP, Brazil.
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Li S, Pan Y. Immunolocalization of connective tissue growth factor, transforming growth factor-beta1 and phosphorylated-SMAD2/3 during the postnatal tooth development and formation of junctional epithelium. Ann Anat 2017; 216:52-59. [PMID: 29175126 DOI: 10.1016/j.aanat.2017.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 09/22/2017] [Accepted: 10/19/2017] [Indexed: 10/18/2022]
Abstract
Connective tissue growth factor (CTGF) is a downstream mediator of transforming growth factor-beta 1 (TGF-β1) and TGF-β1-induced CTGF expression is regulated through SMAD pathway. However, there is no literature showing the expression of TGF-β1-SMAD2/3-CTGF signaling pathway during postnatal tooth development and the formation of junctional epithelium (JE). Hence, we aimed to analyze the localization of TGF-β1, CTGF and phosphorylated SMAD2/3 (p-SMAD2/3) in the developing postnatal rat molars. Wistar rats were killed at postnatal (PN) 0.5, 3.5, 7, 14 and 21days and the upper jaws were processed for immunohistochemistry. At PN0.5 and PN3.5, weak staining for TGF-β1 and CTGF was evident in preameloblasts (PA), while moderate to strong staining was seen in odontoblasts (OD), dental papilla (DPL), secretary ameloblasts (SA), preodontoblasts (PO) and polarized odontoblasts (PoO). There was no staining for p-SMAD2/3 in PA, SA, PO and PoO, although strong staining was localized in DPL. OD was initially moderately positive and then negative for p-SMAD2/3. At PN7, intense staining for TGF-β1 and CTGF was observed in SA, OD, dental pulp (DP) and predentin respectively. p-SMAD2/3 was strongly expressed in DP and moderately expressed in SA and OD. At PN14 and PN21, both reduced enamel epithelium (REE) and JE showed a strong reaction for TGF-β1 and CTGF. p-SMAD2/3 was intensely and weakly expressed in REE and JE respectively. These data demonstrate that the expression of CTGF, TGF-β1 and p-SNAD2/3 is tissue-specific and stage-specific, and indicate a regulatory role for a TGF-β1-SMAD2/3-CTGF signaling pathway in amelogenesis, dentinogenesis and formation of JE.
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Affiliation(s)
- Shubo Li
- The Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Yihuai Pan
- The Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China; Department of Endodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China.
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5
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Differential expression of transforming growth factor-beta1, connective tissue growth factor, phosphorylated-SMAD2/3 and phosphorylated-ERK1/2 during mouse tooth development. J Mol Histol 2017; 48:347-355. [PMID: 28825193 DOI: 10.1007/s10735-017-9733-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/16/2017] [Indexed: 10/19/2022]
Abstract
Connective tissue growth factor (CTGF) is a downstream mediator of transforming growth factor-beta 1 (TGF-β1) and TGF-β1-induced CTGF expression is regulated through SMAD and mitogen-activated protein kinase (MAPK) signaling pathways. The fine modulation of TGF-β1 signaling is very important to the process of tooth development. However, little is known about the localization of CTGF, MAPK and SMAD in the context of TGF-β1 signaling during odontogenesis. Hence, we aimed to investigate the expression of TGF-β1, CTGF, phosphorylated-SMAD2/3 (p-SMAD2/3) and phosphorylated-ERK1/2 (p-ERK1/2). ICR mice heads of embryonic (E) day 13.5, E14.5, E16.5, postnatal (PN) day 0.5 and PN3.5 were processed for immunohistochemistry. Results revealed that at E13.5, TGF-β1 and CTGF were strongly expressed in dental epithelium (DE) and dental mesenchyme (DM), while p-SMAD2/3 was intensely expressed in the internal side of DE. p-ERK1/2 was not present in DE or DM. At E14.5 and E16.5, strong staining for TGF-β1 and CTGF was detected in enamel knot (EK) and dental papilla (DPL). DPL was intensely stained for p-ERK1/2 but negatively stained for p-SMAD2/3. There was no staining for p-SMAD2/3 and p-ERK1/2 in EK. At PN0.5 and PN3.5, moderate to intense staining for TGF-β1 and CTGF was evident in preameloblasts (PA), secretary ameloblasts (SA) and dental pulp (DP). p-SMAD2/3 was strongly expressed in SA and DP but sparsely localized in PA. p-ERK1/2 was intensely expressed in DP, although negative staining was observed in PA and SA. These data demonstrate that TGF-β1 and CTGF show an identical expression pattern, while p-SMAD2/3 and p-ERK1/2 exhibit differential expression, and indicate that p-SMAD2/3 and p-ERK1/2 might play a regulatory role in TGF-β1 induced CTGF expression during tooth development.
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Lelis IMP, Molina GF, Souza C, Perez WB, Laure HJ, Rosa JC, Gerlach RF. Peptide Characterization of Mature Fluorotic and Control Human Enamel. Braz Dent J 2017; 27:66-71. [PMID: 27007349 DOI: 10.1590/0103-6440201600424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/25/2016] [Indexed: 11/22/2022] Open
Abstract
Exposure to high fluoride levels during amelogenesis causes enamel fluorosis. This study aimed to determine and compare the amino acid sequences in the enamel of fluorotic and control teeth. This investigation included enamel samples obtained from erupted and non-erupted third molars with either TF grade 4-6 (n=7) fluorosis or no sign of fluorosis (controls, n=7). The samples were kept frozen at -20 °C until protein extraction. Samples were etched and processed with a cocktail of proteinase inhibitors and immediately analyzed. Matrix Assisted Laser Desorption/Ionization-Time-Of-Flight/Time-of-Flight Mass Spectrometry (MALDI-TOF/TOF) followed by MASCOT search aided the peptides analysis. The more abundant peptides bore the N-terminal amelogenin sequences WYQSIRPPYP (which is specific for the X-encoded amelogenin) and MPLPPHPGHPGYINF (which does not show sexual dimorphism) were not different in control or fluorotic enamel. There was no missing proteolytic cleavage in the fluorotic samples, which suggested that the increased amount of protein described in fluorotic enamel did not stem from the decreased ability of proteinases to cleave the proteins in humans. This study showed how to successfully obtain peptide from superficial enamel. A relatively low number of teeth was sufficient to provide good data on the actual peptides found in mature enamel.
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Affiliation(s)
- Isabel Maria Porto Lelis
- Department of Morphology, Dental School of Piracicaba, Universidade Estadual de Campinas, Piracicaba, SP, Brazil
| | - Gabriela F Molina
- Departament of Morphology, Physiology and Basic Patology, Dental School of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | | | - Walter B Perez
- Department of Stomatology, Health Sciences Center, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Helen J Laure
- Departament of Cellular and Molecular Biology and Bio-Agents Pathogens, Medical School of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - José C Rosa
- Departament of Cellular and Molecular Biology and Bio-Agents Pathogens, Medical School of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Raquel F Gerlach
- Departament of Morphology, Physiology and Basic Patology, Dental School of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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Poulter JA, Brookes SJ, Shore RC, Smith CEL, Abi Farraj L, Kirkham J, Inglehearn CF, Mighell AJ. A missense mutation in ITGB6 causes pitted hypomineralized amelogenesis imperfecta. Hum Mol Genet 2013; 23:2189-97. [PMID: 24319098 PMCID: PMC3959822 DOI: 10.1093/hmg/ddt616] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We identified a family in which pitted hypomineralized amelogenesis imperfecta (AI) with premature enamel failure segregated in an autosomal recessive fashion. Whole-exome sequencing revealed a missense mutation (c.586C>A, p.P196T) in the I-domain of integrin-β6 (ITGB6), which is consistently predicted to be pathogenic by all available programmes and is the only variant that segregates with the disease phenotype. Furthermore, a recent study revealed that mice lacking a functional allele of Itgb6 display a hypomaturation AI phenotype. Phenotypic characterization of affected human teeth in this study showed areas of abnormal prismatic organization, areas of low mineral density and severe abnormal surface pitting in the tooth's coronal portion. We suggest that the pathogenesis of this form of AI may be due to ineffective ligand binding of ITGB6 resulting in either compromised cell-matrix interaction or compromised ITGB6 activation of transforming growth factor-β (TGF-β) impacting indirectly on ameloblast-ameloblast interactions and proteolytic processing of extracellular matrix proteins via MMP20. This study adds to the list of genes mutated in AI and further highlights the importance of cell-matrix interactions during enamel formation.
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Affiliation(s)
- James A Poulter
- Leeds Institutes of Molecular Medicine, University of Leeds, Leeds LS9 7TF, UK
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Smith CE, Hu Y, Richardson AS, Bartlett JD, Hu JCC, Simmer JP. Relationships between protein and mineral during enamel development in normal and genetically altered mice. Eur J Oral Sci 2012; 119 Suppl 1:125-35. [PMID: 22243238 DOI: 10.1111/j.1600-0722.2011.00871.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The purpose of this study was to quantify and compare the amounts of volatiles (mostly protein) and mineral present in developing incisor enamel in normal mice and in those genetically engineered for absence of intact enamelin, ameloblastin, matrix metalloproteinase 20 (MMP20) or kallikrein-related peptidase 4 (KLK4). Data indicated that all mice showed peaks in the gross weight of volatiles and a similar weight of mineral at locations on incisors normally associated with early maturation. Thereafter, the content of volatiles on normal incisors declined rapidly by as much as 62%, but not by 100%, over 2 mm, accompanied by increases of ≈ threefold in mineral weights. Enamelin heterozygous mice (lower incisors) showed a decrease in volatile content across the maturation stage, yet mineral failed to increase significantly. Mmp20 null mice showed no significant loss of volatiles from maturing enamel, yet the amount of mineral increased. Klk4 null mice showed normal mineral acquisition up to early maturation, but the input of new volatiles in mid to late maturation caused the final mineralization to slow below normal levels. These results suggest that it is not only the amount of protein but also the nature or type of protein or fragments present in the local crystallite environment that affects their volumetric expansion as they mature.
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Affiliation(s)
- Charles E Smith
- Facility for Electron Microscopy Research, Department of Anatomy & Cell Biology, and Faculty of Dentistry, McGill University, Montreal, QC, Canada.
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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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El-Sayed W, Shore RC, Parry DA, Inglehearn CF, Mighell AJ. Hypomaturation amelogenesis imperfecta due to WDR72 mutations: a novel mutation and ultrastructural analyses of deciduous teeth. Cells Tissues Organs 2010; 194:60-6. [PMID: 21196691 PMCID: PMC3128158 DOI: 10.1159/000322036] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mutations in WDR72 have been identified in autosomal recessive hypomaturation amelogenesis imperfecta (AI). OBJECTIVE to describe a novel WDR72 mutation and report the ultrastructural enamel phenotype associated with a different WDR72 mutation. METHODS A family segregating autosomal recessive hypomaturation AI was recruited, genomic DNA obtained and WDR72 sequenced. Four deciduous teeth from one individual with a previously published WDR72 mutation, extracted as part of clinical care, were subjected to scanning electron microscopy, energy-dispersive X-ray analysis and transverse microradiography. RESULTS A novel homozygous nonsense mutation, R897X, was identified in WDR72 in a family originating from Pakistan. Ultrastructural analysis of enamel from the deciduous teeth of an AI patient with the WDR72 mutation S783X revealed energy-dispersive X-ray analysis spectra with normal carbon and nitrogen peaks, excluding retention of enamel matrix protein. However, transverse microradiography values were significantly lower for affected teeth when compared to normal teeth, consistent with reduced mineralisation. On scanning electron microscopy the enamel rod form observed was normal, yet with inter-rod enamel more prominent than in controls. This appearance was unaltered following incubation with either α-chymotrypsin or lipase. CONCLUSIONS The novel WDR72 mutation described brings the total reported WDR72 mutations to four. Analyses of deciduous tooth enamel in an individual with a homozygous WDR72 mutation identified changes consistent with a late failure of enamel maturation without retention of matrix proteins. The mechanisms by which intracellular WDR72 influences enamel maturation remain unknown.
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Affiliation(s)
- W El-Sayed
- Leeds Dental Institute, University of Leeds, Leeds, UK
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Porto IM, Saiani RA, Chan KLA, Kazarian SG, Gerlach RF, Bachmann L. Organic and inorganic content of fluorotic rat incisors measured by FTIR spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 77:59-63. [PMID: 20547096 DOI: 10.1016/j.saa.2010.04.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 04/15/2010] [Accepted: 04/27/2010] [Indexed: 05/29/2023]
Abstract
Details on how fluoride interferes in enamel mineralization are still controversial. Therefore, this study aimed at analyzing the organic contents of fluorosis-affected teeth using Fourier Transformation Infrared spectroscopy. To this end, 10 male Wistar rats were divided into two groups: one received 45 ppm fluoride in distilled water for 60 days; the other received distilled water only. Then, the lower incisors were removed and prepared for analysis by two FTIR techniques namely, transmission and micro-ATR. For the first technique, the enamel was powdered, whereas in the second case one fluorotic incisor was cut longitudinally for micro-ATR. Using transmission and powdered samples, FTIR showed a higher C-H content in the fluorotic enamel compared with control enamel (p<0.05, n=4 in the flurotic, and n=5 in the control group). Results from the micro-ATR-FTIR spectroscopic analysis on one longitudinally cut incisor carried out at six points reveal a higher C-H bond content at the surface of the enamel, with values decreasing toward the dentine-enamel junction, and reaching the lowest values at the subsuperficial enamel. These results agree with the morphological data, which indicate that in the rat incisor the fluorotic lesion is superficial, rather than subsuperficial, as in the case of human enamel. The results also suggest that the increased C-H bond content may extend toward the more basal enamel (intraosseous), indicating that fluorotic enamel may intrinsically contain more protein. Finally, particularly when coupled to ATR, FTIR is a suitable tool to study the rat incisor enamel, which is a largely used model of normal and abnormal amelogenesis. Further studies along this line may definitely answer some questions regarding protein content in fluorotic enamel as well as their origin.
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Affiliation(s)
- Isabel Maria Porto
- Department of Morphology, Dental School of Piracicaba, University of Campinas, Piracicaba, Avenida Limeira, 901, 13414-903 Piracicaba, SP, Brazil.
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12
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Merceron G, Escarguel G, Angibault JM, Verheyden-Tixier H. Can dental microwear textures record inter-individual dietary variations? PLoS One 2010; 5:e9542. [PMID: 20209051 PMCID: PMC2832010 DOI: 10.1371/journal.pone.0009542] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 02/01/2010] [Indexed: 11/26/2022] Open
Abstract
Background Dental microwear analyses are commonly used to deduce the diet of extinct mammals. Conventional methods rely on the user identifying features within a 2D image. However, recent interdisciplinary research has lead to the development of an advanced methodology that is free of observer error, based on the automated quantification of 3D surfaces by combining confocal microscopy with scale-sensitive fractal analysis. This method has already proved to be very efficient in detecting dietary differences between species. Focusing on a finer, intra-specific scale of analysis, the aim of this study is to test this method's ability to track such differences between individuals from a single population. Methodology/Principal Findings For the purposes of this study, the 3D molar microwear of 78 individuals from a well-known population of extant roe deer (Capreolus caprelous) is quantified. Multivariate statistical analyses indicate significant seasonal and sexual differences in individual dental microwear design. These are probably the consequence of seasonal variations in fruit, seed and leaf availability, as well as differences in feeding preference between males and females due to distinct energy requirements during periods of rutting, gestation or giving birth. Nevertheless, further investigations using two-block Partial Least-Squares analysis show no strong relationship between individual stomach contents and microwear texture. This is an expected result, assuming that stomach contents are composed of food items ingested during the last few hours whereas dental microwear texture records the physical properties of items eaten over periods of days or weeks. Conclusions/Significance Microwear 3D scale-sensitive fractal analysis does detect differences in diet ranging from the inter-feeding styles scale to the intra-population between-season and between-sex scales. It is therefore a possible tool, to be used with caution, in the further exploration of the feeding biology and ecology of extinct mammals.
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Affiliation(s)
- Gildas Merceron
- UMR CNRS 5125, Paléoenvironnements et Paléobiosphère, Campus de La Doua, Université Claude Bernard Lyon-1, Villeurbanne, France.
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Sawan RMM, Leite GAS, Saraiva MCP, Barbosa F, Tanus-Santos JE, Gerlach RF. Fluoride increases lead concentrations in whole blood and in calcified tissues from lead-exposed rats. Toxicology 2010; 271:21-6. [PMID: 20188782 DOI: 10.1016/j.tox.2010.02.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2009] [Revised: 02/01/2010] [Accepted: 02/02/2010] [Indexed: 10/19/2022]
Abstract
Higher blood lead (BPb) levels have been reported in children living in communities that receive fluoride-treated water. Here, we examined whether fluoride co-administered with lead increases BPb and lead concentrations in calcified tissues in Wistar rats exposed to this metal from the beginning of gestation. We exposed female rats and their offspring to control water (Control Group), 100mg/L of fluoride (F Group), 30mg/L of lead (Pb Group), or 100mg/L of fluoride and 30mg/L of lead (F+Pb Group) from 1 week prior to mating until offspring was 81 days old. Blood and calcified tissues (enamel, dentine, and bone) were harvested at day 81 for lead and fluoride analyses. Higher BPb concentrations were found in the F+Pb Group compared with the Pb Group (76.7+/-11.0microg/dL vs. 22.6+/-8.5microg/dL, respectively; p<0.001). Two- to threefold higher lead concentrations were found in the calcified tissues in the F+Pb Group compared with the Pb Group (all p<0.001). Fluoride concentrations were similar in the F and in the F+Pb Groups. These findings show that fluoride consistently increases BPb and calcified tissues Pb concentrations in animals exposed to low levels of lead and suggest that a biological effect not yet recognized may underlie the epidemiological association between increased BPb lead levels in children living in water-fluoridated communities.
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Affiliation(s)
- Rosangela M M Sawan
- School of Dentistry of Ribeirao Preto, University of Sao Paulo (FORP/USP), Av do Café s/n, 14040-904, Ribeirão Preto, SP, Brazil
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14
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Morphological characterization of rat incisor fluorotic lesions. Arch Oral Biol 2009; 54:1008-15. [DOI: 10.1016/j.archoralbio.2009.08.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2009] [Revised: 07/29/2009] [Accepted: 08/30/2009] [Indexed: 11/19/2022]
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El-Sayed W, Parry DA, Shore RC, Ahmed M, Jafri H, Rashid Y, Al-Bahlani S, Al Harasi S, Kirkham J, Inglehearn CF, Mighell AJ. Mutations in the beta propeller WDR72 cause autosomal-recessive hypomaturation amelogenesis imperfecta. Am J Hum Genet 2009; 85:699-705. [PMID: 19853237 PMCID: PMC2775821 DOI: 10.1016/j.ajhg.2009.09.014] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/22/2009] [Accepted: 09/25/2009] [Indexed: 11/26/2022] Open
Abstract
Healthy dental enamel is the hardest and most highly mineralized human tissue. Though acellular, nonvital, and without capacity for turnover or repair, it can nevertheless last a lifetime. Amelogenesis imperfecta (AI) is a collective term for failure of normal enamel development, covering diverse clinical phenotypes that typically show Mendelian inheritance patterns. One subset, known as hypomaturation AI, is characterised by near-normal volumes of organic enamel matrix but with weak, creamy-brown opaque enamel that fails prematurely after tooth eruption. Mutations in genes critical to enamel matrix formation have been documented, but current understanding of other key events in enamel biomineralization is limited. We investigated autosomal-recessive hypomaturation AI in a consanguineous Pakistani family. A whole-genome SNP autozygosity screen identified a locus on chromosome 15q21.3. Sequencing candidate genes revealed a point mutation in the poorly characterized WDR72 gene. Screening of WDR72 in a panel of nine additional hypomaturation AI families revealed the same mutation in a second, apparently unrelated, Pakistani family and two further nonsense mutations in Omani families. Immunohistochemistry confirmed intracellular localization in maturation-stage ameloblasts. WDR72 function is unknown, but as a putative β propeller is expected to be a scaffold for protein-protein interactions. The nearest homolog, WDR7, is involved in vesicle mobilization and Ca2+-dependent exocytosis at synapses. Vesicle trafficking is important in maturation-stage ameloblasts with respect to secretion into immature enamel and removal of cleaved enamel matrix proteins via endocytosis. This raises the intriguing possibility that WDR72 is critical to ameloblast vesicle turnover during enamel maturation.
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