1
|
Chen S, Zhang Y, Chen H, Zheng W, Hu X, Mao L, Guo X, Lian H. Surface property and in vitro toxicity effect of insoluble particles given by protein corona: Implication for PM cytotoxicity assessment. ECO-ENVIRONMENT & HEALTH 2024; 3:137-144. [PMID: 38638169 PMCID: PMC11021833 DOI: 10.1016/j.eehl.2024.01.011] [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: 10/11/2023] [Revised: 01/18/2024] [Accepted: 01/25/2024] [Indexed: 04/20/2024]
Abstract
In vitro toxicological assessment helps explore key fractions of particulate matter (PM) in association with the toxic mechanism. Previous studies mainly discussed the toxicity effects of the water-soluble and organic-soluble fractions of PM. However, the toxicity of insoluble fractions is relatively poorly understood, and the adsorption of proteins is rarely considered. In this work, the formation of protein corona on the surface of insoluble particles during incubation in a culture medium was investigated. It was found that highly abundant proteins in fetal bovine serum were the main components of the protein corona. The adsorbed proteins increased the dispersion stability of insoluble particles. Meanwhile, the leaching concentrations of some metal elements (e.g., Cu, Zn, and Pb) from PM increased in the presence of proteins. The toxicity effects and potential mechanisms of the PM insoluble particle-protein corona complex on macrophage cells RAW264.7 were discussed. The results revealed that the PM insoluble particle-protein corona complex could influence the phagosome pathway in RAW264.7 cells. Thus, it promoted the intracellular reactive oxygen species generation and induced a greater degree of cell differentiation, significantly altering cell morphology. Consequently, this work sheds new light on the combination of insoluble particles and protein corona in terms of PM cytotoxicity assessment.
Collapse
Affiliation(s)
- Sisi Chen
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing 210023, China
| | - Yexuan Zhang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing 210023, China
| | - Hongjuan Chen
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Science, Nanjing University, Nanjing 210023, China
| | - Weijuan Zheng
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Science, Nanjing University, Nanjing 210023, China
| | - Xin Hu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing 210023, China
| | - Li Mao
- Ministry of Education (MOE) Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Xuewen Guo
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing 210023, China
| | - Hongzhen Lian
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing 210023, China
| |
Collapse
|
2
|
Yang S, Song D, Wang R, Liu M, Tan T, Wang Y, Xie Q, Wang L. Sodium fluoride-induced autophagy of ameloblast-like cells via the p-ULk1/ATG13/LC3B pathway in vitro. Oral Dis 2024. [PMID: 38321366 DOI: 10.1111/odi.14884] [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: 09/22/2022] [Revised: 01/05/2024] [Accepted: 01/18/2024] [Indexed: 02/08/2024]
Abstract
OBJECTIVE To investigate the effects of sodium fluoride on the ameloblast and reveal the mechanism of dental fluorosis. MATERIALS AND METHODS Mouse ameloblast-like cell line (ALC) cells were treated with various concentrations of NaF, and subjected to Incucyte, fluorescence immunoassay, transmission electron microscopy, reverse transcription quantitative polymerase chain reaction (RT-qPCR), western blot for autophagy examination, alkaline phosphatase and alizarin red staining for mineralization after osteogenic induction. RESULTS NaF exerts a dose-dependent inhibitory effect on ALC cell growth. TEM and fluorescence immunoassay showed that 1.5 mM or higher concentrations of NaF could induce a fusion of lysosome and mitochondria, finally increasing the number of autophagosome. RT-qPCR and western blot showed that the upregulation of autophagy related gene 13 (ATG13), downregulation of phosphorylated Unc-51-like kinase 1 (p-ULK1) were found in NaF-induced autophagy of ALC cells. The knockdown of ATG13 could rescue it as well as the expression of p-ULK1 and LC3B. Besides, alizarin red staining showed that fluoride under these concentrations could promote the mineralization of ALC. CONCLUSIONS The data show that fluoride in higher concentration can induce autophagy via the p-ULk1/ATG13/LC3B pathway of ALCs than lower ones promote mineralization in vitro, which provides insight into the function of NaF in the autophagy and mineralization of ameloblast.
Collapse
Affiliation(s)
- S Yang
- Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, China
- National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - D Song
- Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, China
- National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - R Wang
- Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, China
- National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - M Liu
- Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, China
- National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - T Tan
- Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, China
- National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - Y Wang
- Central Laboratory, Peking University School and Hospital of Stomatology, Beijing, China
| | - Q Xie
- Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, China
- National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - L Wang
- Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, China
- National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Beijing, China
| |
Collapse
|
3
|
Jimenez-Armijo A, Morkmued S, Ahumada JT, Kharouf N, de Feraudy Y, Gogl G, Riet F, Niederreither K, Laporte J, Birling MC, Selloum M, Herault Y, Hernandez M, Bloch-Zupan A. The Rogdi knockout mouse is a model for Kohlschütter-Tönz syndrome. Sci Rep 2024; 14:445. [PMID: 38172607 PMCID: PMC10764811 DOI: 10.1038/s41598-023-50870-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 12/27/2023] [Indexed: 01/05/2024] Open
Abstract
Kohlschütter-Tönz syndrome (KTS) is a rare autosomal recessive disorder characterized by severe intellectual disability, early-onset epileptic seizures, and amelogenesis imperfecta. Here, we present a novel Rogdi mutant mouse deleting exons 6-11- a mutation found in KTS patients disabling ROGDI function. This Rogdi-/- mutant model recapitulates most KTS symptoms. Mutants displayed pentylenetetrazol-induced seizures, confirming epilepsy susceptibility. Spontaneous locomotion and circadian activity tests demonstrate Rogdi mutant hyperactivity mirroring patient spasticity. Object recognition impairment indicates memory deficits. Rogdi-/- mutant enamel was markedly less mature. Scanning electron microscopy confirmed its hypomineralized/hypomature crystallization, as well as its low mineral content. Transcriptomic RNA sequencing of postnatal day 5 lower incisors showed downregulated enamel matrix proteins Enam, Amelx, and Ambn. Enamel crystallization appears highly pH-dependent, cycling between an acidic and neutral pH during enamel maturation. Rogdi-/- teeth exhibit no signs of cyclic dental acidification. Additionally, expression changes in Wdr72, Slc9a3r2, and Atp6v0c were identified as potential contributors to these tooth acidification abnormalities. These proteins interact through the acidifying V-ATPase complex. Here, we present the Rogdi-/- mutant as a novel model to partially decipher KTS pathophysiology. Rogdi-/- mutant defects in acidification might explain the unusual combination of enamel and rare neurological disease symptoms.
Collapse
Affiliation(s)
- Alexandra Jimenez-Armijo
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS- UMR7104, Université de Strasbourg, Illkirch, France
| | - Supawich Morkmued
- Pediatrics Division, Department of Preventive Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - José Tomás Ahumada
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS- UMR7104, Université de Strasbourg, Illkirch, France
| | - Naji Kharouf
- Laboratoire de Biomatériaux et Bioingénierie, Inserm UMR_S 1121, Université de Strasbourg, Strasbourg, France
| | - Yvan de Feraudy
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS- UMR7104, Université de Strasbourg, Illkirch, France
- Department of Neuropediatrics, Strasbourg University Hospital, Strasbourg, France
| | - Gergo Gogl
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS- UMR7104, Université de Strasbourg, Illkirch, France
| | - Fabrice Riet
- CNRS, INSERM, CELPHEDIA, PHENOMIN, Institut Clinique de la Souris (ICS), Université de Strasbourg, Illkirch, France
| | - Karen Niederreither
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS- UMR7104, Université de Strasbourg, Illkirch, France
| | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS- UMR7104, Université de Strasbourg, Illkirch, France
| | - Marie Christine Birling
- CNRS, INSERM, CELPHEDIA, PHENOMIN, Institut Clinique de la Souris (ICS), Université de Strasbourg, Illkirch, France
| | - Mohammed Selloum
- CNRS, INSERM, CELPHEDIA, PHENOMIN, Institut Clinique de la Souris (ICS), Université de Strasbourg, Illkirch, France
| | - Yann Herault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS- UMR7104, Université de Strasbourg, Illkirch, France
- CNRS, INSERM, CELPHEDIA, PHENOMIN, Institut Clinique de la Souris (ICS), Université de Strasbourg, Illkirch, France
| | - Magali Hernandez
- Centre Hospitalier Régional Universitaire de Nancy, Competence Center for Rare Oral and Dental Diseases, Université de Lorraine, Nancy, France
| | - Agnès Bloch-Zupan
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS- UMR7104, Université de Strasbourg, Illkirch, France.
- Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France.
- Institut d'études Avancées (USIAS), Université de Strasbourg, Strasbourg, France.
- Pôle de Médecine et Chirurgie Bucco-Dentaires, Hôpital Civil, Centre de Référence des Maladies Rares Orales et Dentaires, O-Rares, Filière Santé Maladies Rares TETE COU, European Reference Network ERN CRANIO, Hôpitaux Universitaires de Strasbourg (HUS), Strasbourg, France.
- Eastman Dental Institute, University College London, London, UK.
| |
Collapse
|
4
|
Loss of BMP2 and BMP4 Signaling in the Dental Epithelium Causes Defective Enamel Maturation and Aberrant Development of Ameloblasts. Int J Mol Sci 2022; 23:ijms23116095. [PMID: 35682776 PMCID: PMC9180982 DOI: 10.3390/ijms23116095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/18/2022] [Accepted: 05/25/2022] [Indexed: 12/10/2022] Open
Abstract
BMP signaling is crucial for differentiation of secretory ameloblasts, the cells that secrete enamel matrix. However, whether BMP signaling is required for differentiation of maturation-stage ameloblasts (MA), which are instrumental for enamel maturation into hard tissue, is hitherto unknown. To address this, we used an in vivo genetic approach which revealed that combined deactivation of the Bmp2 and Bmp4 genes in the murine dental epithelium causes development of dysmorphic and dysfunctional MA. These fail to exhibit a ruffled apical plasma membrane and to reabsorb enamel matrix proteins, leading to enamel defects mimicking hypomaturation amelogenesis imperfecta. Furthermore, subsets of mutant MA underwent pathological single or collective cell migration away from the ameloblast layer, forming cysts and/or exuberant tumor-like and gland-like structures. Massive apoptosis in the adjacent stratum intermedium and the abnormal cell-cell contacts and cell-matrix adhesion of MA may contribute to this aberrant behavior. The mutant MA also exhibited severely diminished tissue non-specific alkaline phosphatase activity, revealing that this enzyme’s activity in MA crucially depends on BMP2 and BMP4 inputs. Our findings show that combined BMP2 and BMP4 signaling is crucial for survival of the stratum intermedium and for proper development and function of MA to ensure normal enamel maturation.
Collapse
|
5
|
Ji M, Duan X, Han X, Sun J, Zhang D. Exogenous transforming growth factor-β1 prevents the inflow of fluoride to ameleoblasts through regulation of voltage-gated chloride channels 5 and 7. Exp Ther Med 2021; 21:615. [PMID: 33936272 PMCID: PMC8082615 DOI: 10.3892/etm.2021.10047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 03/15/2021] [Indexed: 02/07/2023] Open
Abstract
Dental fluorosis is a global issue. Although there are multiple causes of dental fluorosis, the precise mechanism remains controversial. Previous studies have demonstrated that extracellular fluoride may promote an accumulation of fluoride ions in ameloblasts, which may induce oxidative and endoplasmic reticulum stresses, leading to dental fluorosis. However, the exact process by which fluoride ions enter cells has not been determined. In the present study, intracellular fluoride concentration was determined using a newly developed specific fluorescent probe called probe 1. Under high extracellular fluoride concentrations, the fluorescence intensity of the ameloblasts increased, however, exogenous transforming growth factor-β1 (TGF-β1) was able to inhibit the increase. Furthermore, changes in the expression of the voltage-gated chloride channels 5 and 7 (ClC5 and ClC-7), which are responsible for the transport of fluoride were investigated. The results indicated that fluoride reduced the expression of endogenous TGF-β1 and increased the expression of ClC-5 and ClC-7. Additionally, exogenous TGF-β1 reduced the expression of ClC-5 and ClC-7. The results of the present study indicate that exogenous TGF-β1 may prevent accumulation of fluoride in ameloblasts through the regulation of ClC-5 and ClC-7 under high extracellular fluoride concentrations.
Collapse
Affiliation(s)
- Mei Ji
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Xuejing Duan
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Xiaohui Han
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Jing Sun
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Dongsheng Zhang
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| |
Collapse
|
6
|
Wang X, Chao Y, Wang Y, Xu B, Wang C, Li H. Identification of an adaptor protein‐2 mu gene (
AccAP2m
) in
Apis cerana cerana
and its role in oxidative stress responses. J Cell Biochem 2019; 120:16600-16613. [DOI: 10.1002/jcb.28919] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 04/07/2019] [Accepted: 04/11/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Xinxin Wang
- State Key Laboratory of Crop Biology College of Life Sciences, Shandong Agricultural University Taian Shandong PR China
| | - Yuzhen Chao
- State Key Laboratory of Crop Biology College of Life Sciences, Shandong Agricultural University Taian Shandong PR China
| | - Ying Wang
- College of Animal Science and Technology Shandong Agricultural University Taian Shandong PR China
| | - Baohua Xu
- College of Animal Science and Technology Shandong Agricultural University Taian Shandong PR China
| | - Chen Wang
- State Key Laboratory of Crop Biology College of Life Sciences, Shandong Agricultural University Taian Shandong PR China
| | - Han Li
- State Key Laboratory of Crop Biology College of Life Sciences, Shandong Agricultural University Taian Shandong PR China
| |
Collapse
|
7
|
Potential function of TGF-β isoforms in maturation-stage ameloblasts. J Oral Biosci 2019; 61:43-54. [PMID: 30929801 DOI: 10.1016/j.job.2018.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 12/19/2022]
Abstract
OBJECTIVES To investigate potential functions of transforming growth factor-beta (TGF-β) isoforms in maturation-stage ameloblasts during amelogenesis. METHODS In vivo activation of TGF-β was characterized by using matrix metalloproteinase 20 null (Mmp20-/-) and wild-type (Mmp20+/+) mice. Using mHAT9d cells cultured in the presence of each TGF-β isoform, (1) cell proliferation was determined by MTS assay, (2) immunostaining with anti-cleaved caspase-3 monoclonal antibody was performed and apoptotic indices were measured, (3) gene expression was analyzed by RT-qPCR, and (4) the uptake of amelogenin into mHAT9d cells was directly observed using a fluorescence microscope. RESULTS TGF-β1 and TGF-β3 were present in the enamel matrix of developing teeth which were activated by MMP20 in vivo. A genetic study revealed that the three TGF-β isoforms upregulate kallikrein 4 (KLK4) mRNA levels but downregulate carbonic anhydrase II. Moreover, TGF-β1 and TGF-β2 significantly upregulated the mRNA level of amelotin, whereas TGF-β3 dramatically downregulated the mRNA levels of odontogenic ameloblast-associated protein (ODAM), family with sequence similarity 83 member H (FAM83H), and alkaline phosphatase (ALP). Immunostaining analysis showed that the apoptosis of mHAT9d cells is induced by three TGF-β isoforms, with TGF-β3 being most effective. Both TGF-β1 and TGF-β3 induced endocytosis of amelogenin. CONCLUSIONS We propose that TGF-β is regulated in an isoform-specific manner to perform multiple biological functions such as gene expression related to the structure of basal lamina/ameloblasts, mineral ion transport, apoptosis, and endocytosis in maturation-stage ameloblasts.
Collapse
|
8
|
Ji M, Xiao L, Xu L, Huang S, Zhang D. How pH is regulated during amelogenesis in dental fluorosis. Exp Ther Med 2018; 16:3759-3765. [PMID: 30402142 DOI: 10.3892/etm.2018.6728] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/01/2017] [Indexed: 12/14/2022] Open
Abstract
Amelogenesis is a complicated process that concerns the interaction between growing hydroxyapatite crystals and extracellular proteins, which requires the tight regulation of pH. In dental fluorosis, the balance of pH regulation is broken, leading to abnormal mineralization. The current review focuses on the electrolyte transport processes associated with pH homeostasis, particularly regarding the changes in ion transporters that occur during amelogenesis, following exposure to excessive fluoride. Furthermore, the possible mechanism of fluorosis is discussed on the basis of acid hypothesis. There are two main methods by which F- accelerates crystal formation in ameloblasts. Firstly, it induces the release of protons, lowering the pH of the cell microenvironment. The decreased pH stimulates the upregulation of ion transporters, which attenuates further declines in the pH. Secondly, F- triggers an unknown signaling pathway, causing changes in the transcription of ion transporters and upregulating the expression of bicarbonate transporters. This results in the release of a large amount of bicarbonate from ameloblasts, which may neutralize the pH to form a microenvironment that favors crystal nucleation. The decreased pH stimulates the diffusion of F- into the cytoplasm of amelobalsts along the concentration gradient formed by the release of protons. The retention of F- causes a series of pathological changes, including oxidative and endoplasmic reticulum stress. If the buffering capacity of ameloblasts facing F- toxicity holds, normal mineralization occurs; however, if F- levels are high enough to overwhelm the buffering capacity of ameloblasts, abnormal mineralization occurs, leading to dental fluorosis.
Collapse
Affiliation(s)
- Mei Ji
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Lili Xiao
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Le Xu
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Shengyun Huang
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Dongsheng Zhang
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| |
Collapse
|
9
|
Kim HE, Hong JH. The overview of channels, transporters, and calcium signaling molecules during amelogenesis. Arch Oral Biol 2018; 93:47-55. [PMID: 29803993 DOI: 10.1016/j.archoralbio.2018.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 05/18/2018] [Accepted: 05/19/2018] [Indexed: 01/02/2023]
Abstract
Enamel is a highly calcified tissue. Its formation requires a progressive and dynamic system for the regulation of electrolyte concentration by enamel epithelia. A critical function of enamel epithelial cells, ameloblasts, is the secretion and movement of electrolytes via various channels and transporters to develop the enamel tissue. Enamel formation generates protons, which need to be neutralised. Thus, ameloblasts possess a buffering system to sustain mineral accretion. Normal tooth formation involves stage-dependent net fluctuations in pH during amelogenesis. To date, all of our information about ion transporters in dental enamel tissue is based solely on immunostaining-expression techniques. This review critically evaluates the current understanding and recent discoveries and physiological role of ion channels and transporters, Mg2+ transporters, and Ca2+ regulatory proteins during amelogenesis in enamel formation. The ways in which ameloblasts modulate ions are discussed in the context of current research for developing a novel morphologic-functional model of enamel maturation.
Collapse
Affiliation(s)
- Hee-Eun Kim
- Department of Dental Hygiene, College of Health Science, Gachon University, 191 Hambangmoe-ro, Yeonsu-gu, Incheon, 21936, South Korea
| | - Jeong Hee Hong
- Department of Physiology, College of Medicine, Lee Gil Ya Cancer and Diabetes Institute, GAIHST, Gachon University, Incheon, 21999, South Korea.
| |
Collapse
|
10
|
Abstract
Amelogenesis (tooth enamel formation) is a biomineralization process consisting primarily of two stages (secretory stage and maturation stage) with unique features. During the secretory stage, the inner epithelium of the enamel organ (i.e., the ameloblast cells) synthesizes and secretes enamel matrix proteins (EMPs) into the enamel space. The protein-rich enamel matrix forms a highly organized architecture in a pH-neutral microenvironment. As amelogenesis transitions to maturation stage, EMPs are degraded and internalized by ameloblasts through endosomal-lysosomal pathways. Enamel crystallite formation is initiated early in the secretory stage, however, during maturation stage the more rapid deposition of calcium and phosphate into the enamel space results in a rapid expansion of crystallite length and mineral volume. During maturation-stage amelogenesis, the pH value of enamel varies considerably from slightly above neutral to acidic. Extracellular acid-base balance during enamel maturation is tightly controlled by ameloblast-mediated regulatory networks, which include significant synthesis and movement of bicarbonate ions from both the enamel papillary layer cells and ameloblasts. In this review we summarize the carbonic anhydrases and the carbonate transporters/exchangers involved in pH regulation in maturation-stage amelogenesis. Proteins that have been shown to be instrumental in this process include CA2, CA6, CFTR, AE2, NBCe1, SLC26A1/SAT1, SLC26A3/DRA, SLC26A4/PDS, SLC26A6/PAT1, and SLC26A7/SUT2. In addition, we discuss the association of miRNA regulation with bicarbonate transport in tooth enamel formation.
Collapse
Affiliation(s)
- Kaifeng Yin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, CSA103, Los Angeles, CA, 90033, USA
- Department of Orthodontics, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - Michael L Paine
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, CSA103, Los Angeles, CA, 90033, USA.
| |
Collapse
|
11
|
Varga G, DenBesten P, Rácz R, Zsembery Á. Importance of bicarbonate transport in pH control during amelogenesis - need for functional studies. Oral Dis 2017; 24:879-890. [PMID: 28834043 DOI: 10.1111/odi.12738] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 08/13/2017] [Indexed: 12/27/2022]
Abstract
Dental enamel, the hardest mammalian tissue, is produced by ameloblasts. Ameloblasts show many similarities to other transporting epithelia although their secretory product, the enamel matrix, is quite different. Ameloblasts direct the formation of hydroxyapatite crystals, which liberate large quantities of protons that then need to be buffered to allow mineralization to proceed. Buffering requires a tight pH regulation and secretion of bicarbonate by ameloblasts. Many investigations have used immunohistochemical and knockout studies to determine the effects of these genes on enamel formation, but up till recently very little functional data were available for mineral ion transport. To address this, we developed a novel 2D in vitro model using HAT-7 ameloblast cells. HAT-7 cells can be polarized and develop functional tight junctions. Furthermore, they are able to accumulate bicarbonate ions from the basolateral to the apical fluid spaces. We propose that in the future, the HAT-7 2D system along with similar cellular models will be useful to functionally model ion transport processes during amelogenesis. Additionally, we also suggest that similar approaches will allow a better understanding of the regulation of the cycling process in maturation-stage ameloblasts, and the pH sensory mechanisms, which are required to develop sound, healthy enamel.
Collapse
Affiliation(s)
- G Varga
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - P DenBesten
- Department of Orofacial Sciences, University of California, San Francisco, CA, USA
| | - R Rácz
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Á Zsembery
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| |
Collapse
|
12
|
Brookes SJ, Barron MJ, Dixon MJ, Kirkham J. The Unfolded Protein Response in Amelogenesis and Enamel Pathologies. Front Physiol 2017; 8:653. [PMID: 28951722 PMCID: PMC5599773 DOI: 10.3389/fphys.2017.00653] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
During the secretory phase of their life-cycle, ameloblasts are highly specialized secretory cells whose role is to elaborate an extracellular matrix that ultimately confers both form and function to dental enamel, the most highly mineralized of all mammalian tissues. In common with many other “professional” secretory cells, ameloblasts employ the unfolded protein response (UPR) to help them cope with the large secretory cargo of extracellular matrix proteins transiting their ER (endoplasmic reticulum)/Golgi complex and so minimize ER stress. However, the UPR is a double-edged sword, and, in cases where ER stress is severe and prolonged, the UPR switches from pro-survival to pro-apoptotic mode. The purpose of this review is to consider the role of the ameloblast UPR in the biology and pathology of amelogenesis; specifically in respect of amelogenesis imperfecta (AI) and fluorosis. Some forms of AI appear to correspond to classic proteopathies, where pathological intra-cellular accumulations of protein tip the UPR toward apoptosis. Fluorosis also involves the UPR and, while not of itself a classic proteopathic disease, shares some common elements through the involvement of the UPR. The possibility of therapeutic intervention by pharmacological modulation of the UPR in AI and fluorosis is also discussed.
Collapse
Affiliation(s)
- Steven J Brookes
- Division of Oral Biology, School of Dentistry, University of Leeds, St James's University HospitalLeeds, United Kingdom
| | - Martin J Barron
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of ManchesterManchester, United Kingdom
| | - Michael J Dixon
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of ManchesterManchester, United Kingdom
| | - Jennifer Kirkham
- Division of Oral Biology, School of Dentistry, University of Leeds, St James's University HospitalLeeds, United Kingdom
| |
Collapse
|
13
|
Lacruz RS, Habelitz S, Wright JT, Paine ML. DENTAL ENAMEL FORMATION AND IMPLICATIONS FOR ORAL HEALTH AND DISEASE. Physiol Rev 2017; 97:939-993. [PMID: 28468833 DOI: 10.1152/physrev.00030.2016] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 12/16/2022] Open
Abstract
Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function.
Collapse
Affiliation(s)
- Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Stefan Habelitz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - J Timothy Wright
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Michael L Paine
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| |
Collapse
|
14
|
Pham CD, Smith CE, Hu Y, Hu JCC, Simmer JP, Chun YHP. Endocytosis and Enamel Formation. Front Physiol 2017; 8:529. [PMID: 28824442 PMCID: PMC5534449 DOI: 10.3389/fphys.2017.00529] [Citation(s) in RCA: 14] [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: 04/30/2017] [Accepted: 07/10/2017] [Indexed: 12/12/2022] Open
Abstract
Enamel formation requires consecutive stages of development to achieve its characteristic extreme mineral hardness. Mineralization depends on the initial presence then removal of degraded enamel proteins from the matrix via endocytosis. The ameloblast membrane resides at the interface between matrix and cell. Enamel formation is controlled by ameloblasts that produce enamel in stages to build the enamel layer (secretory stage) and to reach final mineralization (maturation stage). Each stage has specific functional requirements for the ameloblasts. Ameloblasts adopt different cell morphologies during each stage. Protein trafficking including the secretion and endocytosis of enamel proteins is a fundamental task in ameloblasts. The sites of internalization of enamel proteins on the ameloblast membrane are specific for every stage. In this review, an overview of endocytosis and trafficking of vesicles in ameloblasts is presented. The pathways for internalization and routing of vesicles are described. Endocytosis is proposed as a mechanism to remove debris of degraded enamel protein and to obtain feedback from the matrix on the status of the maturing enamel.
Collapse
Affiliation(s)
- Cong-Dat Pham
- Department of Periodontics, School of Dentistry, University of Texas Health Science Center at San AntonioSan Antonio, TX, United States
| | - Charles E. Smith
- Department of Anatomy and Cell Biology, McGill UniversityMontreal, QC, Canada
- Department of Biologic and Materials Sciences, University of MichiganAnn Arbor, MI, United States
| | - Yuanyuan Hu
- Department of Biologic and Materials Sciences, University of MichiganAnn Arbor, MI, United States
| | - Jan C-C. Hu
- Department of Biologic and Materials Sciences, University of MichiganAnn Arbor, MI, United States
| | - James P. Simmer
- Department of Biologic and Materials Sciences, University of MichiganAnn Arbor, MI, United States
| | - Yong-Hee P. Chun
- Department of Periodontics, School of Dentistry, University of Texas Health Science Center at San AntonioSan Antonio, TX, United States
- Department of Cell Systems & Anatomy, School of Medicine, University of Texas Health Science Center at San AntonioSan Antonio, TX, United States
| |
Collapse
|
15
|
Lacruz RS. Enamel: Molecular identity of its transepithelial ion transport system. Cell Calcium 2017; 65:1-7. [PMID: 28389033 PMCID: PMC5944837 DOI: 10.1016/j.ceca.2017.03.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/14/2022]
Abstract
Enamel is the most calcified tissue in vertebrates. It differs from bone in a number of characteristics including its origin from ectodermal epithelium, lack of remodeling capacity by the enamel forming cells, and absence of collagen. The enamel-forming cells known as ameloblasts, choreograph first the synthesis of a unique protein-rich matrix, followed by the mineralization of this matrix into a tissue that is ∼95% mineral. To do this, ameloblasts arrange the coordinated movement of ions across a cell barrier while removing matrix proteins and monitoring extracellular pH using a variety of buffering systems to enable the growth of carbonated apatite crystals. Although our knowledge of these processes and the molecular identity of the proteins involved in transepithelial ion transport has increased in the last decade, it remains limited compared to other cells. Here we present an overview of the evolution and development of enamel, its differences with bone, and describe the ion transport systems associated with ameloblasts.
Collapse
Affiliation(s)
- Rodrigo S Lacruz
- Dept. Basic Science and Craniofacial Biology, New York University College of Dentistry, 345 East 24th Street, New York, NY 10010, United States.
| |
Collapse
|
16
|
Yin K, Guo J, Lin W, Robertson SYT, Soleimani M, Paine ML. Deletion of Slc26a1 and Slc26a7 Delays Enamel Mineralization in Mice. Front Physiol 2017; 8:307. [PMID: 28559854 PMCID: PMC5432648 DOI: 10.3389/fphys.2017.00307] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/28/2017] [Indexed: 12/12/2022] Open
Abstract
Amelogenesis features two major developmental stages—secretory and maturation. During maturation stage, hydroxyapatite deposition and matrix turnover require delicate pH regulatory mechanisms mediated by multiple ion transporters. Several members of the Slc26 gene family (Slc26a1, Slc26a3, Slc26a4, Slc26a6, and Slc26a7), which exhibit bicarbonate transport activities, have been suggested by previous studies to be involved in maturation-stage amelogenesis, especially the key process of pH regulation. However, details regarding the functional role of these genes in enamel formation are yet to be clarified, as none of the separate mutant animal lines demonstrates any discernible enamel defects. Continuing with our previous investigation of Slc26a1−/− and Slc26a7−/− animal models, we generated a double-mutant animal line with the absence of both Slc26a1 and Slc26a7. We showed in the present study that the double-mutant enamel density was significantly lower in the regions that represent late maturation-, maturation- and secretory-stage enamel development in wild-type mandibular incisors. However, the “maturation” and “secretory” enamel microstructures in double-mutant animals resembled those observed in wild-type secretory and/or pre-secretory stages. Elemental composition analysis revealed a lack of mineral deposition and an accumulation of carbon and chloride in double-mutant enamel. Deletion of Slc26a1 and Slc26a7 did not affect the stage-specific morphology of the enamel organ. Finally, compensatory expression of pH regulator genes and ion transporters was detected in maturation-stage enamel organs of double-mutant animals when compared to wild-type. Combined with the findings from our previous study, these data indicate the involvement of SLC26A1and SLC26A7 as key ion transporters in the pH regulatory network during enamel maturation.
Collapse
Affiliation(s)
- Kaifeng Yin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA.,Department of Orthodontics, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
| | - Jing Guo
- Department of Endodontics, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
| | - Wenting Lin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
| | - Sarah Y T Robertson
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
| | - Manoocher Soleimani
- Department of Medicine, University of Cincinnati, Research Services, Veterans Affairs Medical CenterCincinnati, OH, USA
| | - Michael L Paine
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern CaliforniaLos Angeles, CA, USA
| |
Collapse
|
17
|
Johnson L, Ganss B, Wang A, Zirngibl RA, Johnson DE, Owen C, Bradley G, Voronov I. V-ATPases Containing a3 Subunit Play a Direct Role in Enamel Development in Mice. J Cell Biochem 2017; 118:3328-3340. [PMID: 28295540 DOI: 10.1002/jcb.25986] [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: 02/10/2017] [Accepted: 03/09/2017] [Indexed: 12/17/2022]
Abstract
Vacuolar H+ -ATPases (V-ATPases) are ubiquitous multisubunit proton pumps responsible for organellar pH maintenance. Mutations in the a3 subunit of V-ATPases cause autosomal recessive osteopetrosis, a rare disease due to impaired bone resorption. Patients with osteopetrosis also display dental anomalies, such as enamel defects; however, it is not clear whether these enamel abnormalities are a direct consequence of the a3 mutations. We investigated enamel mineralization, spatiotemporal expression of enamel matrix proteins and the a3 protein during tooth development using an osteopetrotic mouse model with a R740S point mutation in the V-ATPase a3 subunit. Histology revealed aberrations in both crown and root development, whereas SEM analysis demonstrated delayed enamel mineralization in homozygous animals. Enamel thickness and mineralization were significantly decreased in homozygous mice as determined by μCT analysis. The expression patterns of the enamel matrix proteins amelogenin, amelotin, and odontogenic ameloblast-associated protein (ODAM) suggested a delay in transition to the maturation stage in homozygous animals. Protein expression of the a3 subunit was detected in ameloblasts in all three genotypes, suggesting that a3-containing V-ATPases play a direct role in amelogenesis, and mutations in a3 delay transition from the secretory to the maturation stage, resulting in hypomineralized and hypoplastic enamel. J. Cell. Biochem. 118: 3328-3340, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Lisa Johnson
- Faculty of Dentistry, Department of Oral Pathology, University of Toronto, Toronto, Ontario, Canada.,Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Bernhard Ganss
- Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada.,Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Andrew Wang
- Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Ralph A Zirngibl
- Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Danielle E Johnson
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Celeste Owen
- Centre for Modeling Human Disease, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
| | - Grace Bradley
- Faculty of Dentistry, Department of Oral Pathology, University of Toronto, Toronto, Ontario, Canada
| | - Irina Voronov
- Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
18
|
MiR-153 Regulates Amelogenesis by Targeting Endocytotic and Endosomal/lysosomal Pathways-Novel Insight into the Origins of Enamel Pathologies. Sci Rep 2017; 7:44118. [PMID: 28287144 PMCID: PMC5347039 DOI: 10.1038/srep44118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 02/03/2017] [Indexed: 12/15/2022] Open
Abstract
Amelogenesis imperfecta (AI) is group of inherited disorders resulting in enamel pathologies. The involvement of epigenetic regulation in the pathogenesis of AI is yet to be clarified due to a lack of knowledge about amelogenesis. Our previous genome-wide microRNA and mRNA transcriptome analyses suggest a key role for miR-153 in endosome/lysosome-related pathways during amelogenesis. Here we show that miR-153 is significantly downregulated in maturation ameloblasts compared with secretory ameloblasts. Within ameloblast-like cells, upregulation of miR-153 results in the downregulation of its predicted targets including Cltc, Lamp1, Clcn4 and Slc4a4, and a number of miRNAs implicated in endocytotic pathways. Luciferase reporter assays confirmed the predicted interactions between miR-153 and the 3'-UTRs of Cltc, Lamp1 (in a prior study), Clcn4 and Slc4a4. In an enamel protein intake assay, enamel cells transfected with miR-153 show a decreased ability to endocytose enamel proteins. Finally, microinjection of miR-153 in the region of mouse first mandibular molar at postnatal day 8 (PN8) induced AI-like pathologies when the enamel development reached maturity (PN12). In conclusion, miR-153 regulates maturation-stage amelogenesis by targeting key genes involved in the endocytotic and endosomal/lysosomal pathways, and disruption of miR-153 expression is a potential candidate etiologic factor contributing to the occurrence of AI.
Collapse
|
19
|
Jin Y, Wang C, Cheng S, Zhao Z, Li J. MicroRNA control of tooth formation and eruption. Arch Oral Biol 2017; 73:302-310. [DOI: 10.1016/j.archoralbio.2016.08.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 08/20/2016] [Accepted: 08/22/2016] [Indexed: 01/01/2023]
|
20
|
Yin K, Lei Y, Wen X, Lacruz RS, Soleimani M, Kurtz I, Snead ML, White SN, Paine ML. SLC26A Gene Family Participate in pH Regulation during Enamel Maturation. PLoS One 2015; 10:e0144703. [PMID: 26671068 PMCID: PMC4679777 DOI: 10.1371/journal.pone.0144703] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/23/2015] [Indexed: 12/15/2022] Open
Abstract
The bicarbonate transport activities of Slc26a1, Slc26a6 and Slc26a7 are essential to physiological processes in multiple organs. Although mutations of Slc26a1, Slc26a6 and Slc26a7 have not been linked to any human diseases, disruption of Slc26a1, Slc26a6 or Slc26a7 expression in animals causes severe dysregulation of acid-base balance and disorder of anion homeostasis. Amelogenesis, especially the enamel formation during maturation stage, requires complex pH regulation mechanisms based on ion transport. The disruption of stage-specific ion transporters frequently results in enamel pathosis in animals. Here we present evidence that Slc26a1, Slc26a6 and Slc26a7 are highly expressed in rodent incisor ameloblasts during maturation-stage tooth development. In maturation-stage ameloblasts, Slc26a1, Slc26a6 and Slc26a7 show a similar cellular distribution as the cystic fibrosis transmembrane conductance regulator (Cftr) to the apical region of cytoplasmic membrane, and the distribution of Slc26a7 is also seen in the cytoplasmic/subapical region, presumably on the lysosomal membrane. We have also examined Slc26a1 and Slc26a7 null mice, and although no overt abnormal enamel phenotypes were observed in Slc26a1-/- or Slc26a7-/- animals, absence of Slc26a1 or Slc26a7 results in up-regulation of Cftr, Ca2, Slc4a4, Slc4a9 and Slc26a9, all of which are involved in pH homeostasis, indicating that this might be a compensatory mechanism used by ameloblasts cells in the absence of Slc26 genes. Together, our data show that Slc26a1, Slc26a6 and Slc26a7 are novel participants in the extracellular transport of bicarbonate during enamel maturation, and that their functional roles may be achieved by forming interaction units with Cftr.
Collapse
Affiliation(s)
- Kaifeng Yin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern California, Los Angeles, California, United States of America
| | - Yuejuan Lei
- Department of Operative and Endodontics, The Affiliated Stomatological Hospital, Guangxi Medical University, Nanning, Guangxi, China
| | - Xin Wen
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern California, Los Angeles, California, United States of America
| | - Rodrigo S. Lacruz
- Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, New York, United States of America
| | - Manoocher Soleimani
- Department of Medicine, University of Cincinnati, Research Services, Veterans Affairs Medical Center, Cincinnati, Ohio, United States of America
| | - Ira Kurtz
- Division of Nephrology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - Malcolm L. Snead
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern California, Los Angeles, California, United States of America
| | - Shane N. White
- School of Dentistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Michael L. Paine
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry of University of Southern California, Los Angeles, California, United States of America
- * E-mail:
| |
Collapse
|
21
|
V-type ATPase proton pump expression during enamel formation. Matrix Biol 2015; 52-54:234-245. [PMID: 26586472 DOI: 10.1016/j.matbio.2015.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 10/29/2015] [Accepted: 11/09/2015] [Indexed: 01/12/2023]
Abstract
Several diseases such as proximal and distal renal tubular acidosis and osteoporosis are related to intracellular pH dysregulation resulting from mutations in genes coding for ion channels, including proteins comprising the proton-pumping V-type ATPase. V-type ATPase is a multi-subunit protein complex expressed in enamel forming cells. V-type ATPase plays a key role in enamel development, specifically lysosomal acidification, yet our understanding of the relationship between the endocytotic activities and dental health and disease is limited. The objective of this study is to better understand the ameloblast-associated pH regulatory networks essential for amelogenesis. Quantitative RT-PCR was performed on tissues from secretory-stage and maturation-stage enamel organs to determine which of the V-type ATPase subunits are most highly upregulated during maturation-stage amelogenesis: a time when ameloblast endocytotic activity is highest. Western blot analyses, using specific antibodies to four of the V-type ATPase subunits (Atp6v0d2, Atp6v1b2, Atp6v1c1 and Atp6v1e1), were then applied to validate much of the qPCR data. Immunohistochemistry using these same four antibodies was also performed to identify the spatiotemporal expression profiles of individual V-type ATPase subunits. Our data show that cytoplasmic V-type ATPase is significantly upregulated in enamel organ cells during maturation-stage when compared to secretory-stage. These data likely relate to the higher endocytotic activities, and the greater need for lysosomal acidification, during maturation-stage amelogenesis. It is also apparent from our immunolocalization data, using antibodies against two of the V-type ATPase subunits (Atp6v1c1 and Atp6v1e1), that significant expression is seen at the apical membrane of maturation-stage ameloblasts. Others have also identified this V-type ATPase expression profile at the apical membrane of maturation ameloblasts. Collectively, these data better define the expression and role of the V-type ATPase proton pump in the enamel organ during amelogenesis.
Collapse
|
22
|
Dental enamel cells express functional SOCE channels. Sci Rep 2015; 5:15803. [PMID: 26515404 PMCID: PMC4626795 DOI: 10.1038/srep15803] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 10/06/2015] [Indexed: 12/14/2022] Open
Abstract
Dental enamel formation requires large quantities of Ca(2+) yet the mechanisms mediating Ca(2+) dynamics in enamel cells are unclear. Store-operated Ca(2+) entry (SOCE) channels are important Ca(2+) influx mechanisms in many cells. SOCE involves release of Ca(2+) from intracellular pools followed by Ca(2+) entry. The best-characterized SOCE channels are the Ca(2+) release-activated Ca(2+) (CRAC) channels. As patients with mutations in the CRAC channel genes STIM1 and ORAI1 show abnormal enamel mineralization, we hypothesized that CRAC channels might be an important Ca(2+) uptake mechanism in enamel cells. Investigating primary murine enamel cells, we found that key components of CRAC channels (ORAI1, ORAI2, ORAI3, STIM1, STIM2) were expressed and most abundant during the maturation stage of enamel development. Furthermore, inositol 1,4,5-trisphosphate receptor (IP3R) but not ryanodine receptor (RyR) expression was high in enamel cells suggesting that IP3Rs are the main ER Ca(2+) release mechanism. Passive depletion of ER Ca(2+) stores with thapsigargin resulted in a significant raise in [Ca(2+)]i consistent with SOCE. In cells pre-treated with the CRAC channel blocker Synta-66 Ca(2+) entry was significantly inhibited. These data demonstrate that enamel cells have SOCE mediated by CRAC channels and implicate them as a mechanism for Ca(2+) uptake in enamel formation.
Collapse
|
23
|
Guo J, Bervoets TJM, Henriksen K, Everts V, Bronckers ALJJ. Null mutation of chloride channel 7 (Clcn7) impairs dental root formation but does not affect enamel mineralization. Cell Tissue Res 2015; 363:361-70. [PMID: 26346547 PMCID: PMC4735262 DOI: 10.1007/s00441-015-2263-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 07/29/2015] [Indexed: 12/23/2022]
Abstract
ClC-7, located in late endosomes and lysosomes, is critical for the function of osteoclasts. Secretion of Cl(-) by the ruffled border of osteoclasts enables H(+) secretion by v-H(+)-ATPases to dissolve bone mineral. Mice lacking ClC-7 show altered lysosomal function that leads to severe lysosomal storage. Maturation ameloblasts are epithelial cells with a ruffled border that secrete Cl(-) as well as endocytose and digest large quantities of enamel matrix proteins during formation of dental enamel. We tested the hypothesis that ClC-7 in maturation ameloblasts is required for intracellular digestion of matrix fragments to complete enamel mineralization. Craniofacial bones and developing teeth in Clcn7(-/-) mice were examined by micro-CT, immunohistochemistry, quantified histomorphometry and electron microscopy. Osteoclasts and ameloblasts in wild-type mice stained intensely with anti-ClC-7 antibody but not in Clcn7(-/-) mice. Craniofacial bones in Clcn7(-/-) mice were severely osteopetrotic and contained 1.4- to 1.6-fold more bone volume, which was less mineralized than the wild-type littermates. In Clcn7(-/-) mice maturation ameloblasts and osteoclasts highly expressed Ae2 as in wild-type mice. However, teeth failed to erupt, incisors were much shorter and roots were disfigured. Molars formed a normal dental crown. In compacted teeth, dentin was slightly less mineralized, enamel did not retain a matrix and mineralized fairly normal. We concluded that ClC-7 is essential for osteoclasts to resorb craniofacial bones to enable tooth eruption and root development. Disruption of Clcn7 reduces bone and dentin mineral density but does not affect enamel mineralization.
Collapse
Affiliation(s)
- Jing Guo
- Department Oral Cell Biology, Academic Center of Dentistry Amsterdam (ACTA), University of Amsterdam and VU-University of Amsterdam, MOVE Research Institute, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands. .,School of Stomatology/Dental Clinic, Zhejiang Chinese Medical University, Mailbox 97, Binwen Road 548, Binjiang District, 310053, Hangzhou, China.
| | - Theodore J M Bervoets
- Department Oral Cell Biology, Academic Center of Dentistry Amsterdam (ACTA), University of Amsterdam and VU-University of Amsterdam, MOVE Research Institute, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Kim Henriksen
- Nordic Bioscience Biomarkers and Research A/S, Hovedgade 207, 2730, Herlev, Denmark
| | - Vincent Everts
- Department Oral Cell Biology, Academic Center of Dentistry Amsterdam (ACTA), University of Amsterdam and VU-University of Amsterdam, MOVE Research Institute, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Antonius L J J Bronckers
- Department Oral Cell Biology, Academic Center of Dentistry Amsterdam (ACTA), University of Amsterdam and VU-University of Amsterdam, MOVE Research Institute, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| |
Collapse
|
24
|
Nurbaeva MK, Eckstein M, Snead ML, Feske S, Lacruz RS. Store-operated Ca2+ Entry Modulates the Expression of Enamel Genes. J Dent Res 2015; 94:1471-7. [PMID: 26232387 DOI: 10.1177/0022034515598144] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Dental enamel formation is an intricate process tightly regulated by ameloblast cells. The correct spatiotemporal patterning of enamel matrix protein (EMP) expression is fundamental to orchestrate the formation of enamel crystals, which depend on a robust supply of Ca2+. In the extracellular milieu, Ca2+ -EMP interactions occur at different levels. Despite its recognized role in enamel development, the molecular machinery involved in Ca2+ homeostasis in ameloblasts remains poorly understood. A common mechanism for Ca2+ influx is store-operated Ca2+ entry (SOCE). We evaluated the possibility that Ca2+ influx in enamel cells might be mediated by SOCE and the Ca2+ release-activated Ca2+ (CRAC) channel, the prototypical SOCE channel. Using ameloblast-like LS8 cells, we demonstrate that these cells express Ca2+ -handling molecules and mediate Ca2+ influx through SOCE. As a rise in the cytosolic Ca2+ concentration is a versatile signal that can modulate gene expression, we assessed whether SOCE in enamel cells had any effect on the expression of EMPs. Our results demonstrate that stimulating LS8 cells or murine primary enamel organ cells with thapsigargin to activate SOCE leads to increased expression of Amelx, Ambn, Enam, Mmp20. This effect is reversed when cells are treated with a CRAC channel inhibitor. These data indicate that Ca2+ influx in LS8 cells and enamel organ cells is mediated by CRAC channels and that Ca2+ signals enhance the expression of EMPs. Ca2+ plays an important role not only in mineralizing dental enamel but also in regulating the expression of EMPs.
Collapse
Affiliation(s)
- M K Nurbaeva
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, USA
| | - M Eckstein
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, USA
| | - M L Snead
- Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - S Feske
- Department of Pathology, NYU School of Medicine, New York, NY, USA
| | - R S Lacruz
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, USA
| |
Collapse
|
25
|
Varga G, Kerémi B, Bori E, Földes A. Function and repair of dental enamel - Potential role of epithelial transport processes of ameloblasts. Pancreatology 2015; 15:S55-60. [PMID: 25747281 DOI: 10.1016/j.pan.2015.01.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 01/28/2015] [Indexed: 12/11/2022]
Abstract
The hardest mammalian tissue, dental enamel is produced by ameloblasts, which are electrolyte-transporting epithelial cells. Although the end product is very different, they show many similarities to transporting epithelia of the pancreas, salivary glands and kidney. Enamel is produced in a multi-step epithelial secretory process that features biomineralization which is an interplay of secreted ameloblast specific proteins and the time-specific transport of minerals, protons and bicarbonate. First, "secretory" ameloblasts form the entire thickness of the enamel layer, but with low mineral content. Then they differentiate into "maturation" ameloblasts, which remove organic matrix from the enamel and in turn further build up hydroxyapatite crystals. The protons generated by hydroxyapatite formation need to be buffered, otherwise enamel will not attain full mineralization. Buffering requires a tight pH regulation and secretion of bicarbonate by ameloblasts. The whole process has been the focus of many immunohistochemical and gene knock-out studies, but, perhaps surprisingly, no functional data existed for mineral ion transport by ameloblasts. However, recent studies including ours provided a better insight for molecular mechanism of mineral formation. The secretory regulation is not completely known as yet, but its significance is crucial. Impairing regulation retards or prevents completion of enamel mineralization and results in the development of hypomineralized enamel that easily erodes after dental eruption. Factors that impair this function are fluoride and disruption of pH regulators. Revealing these factors may eventually lead to the treatment of enamel hypomineralization related to genetic or environmentally induced malformation.
Collapse
Affiliation(s)
- Gábor Varga
- Department of Oral Biology, Semmelweis University, Budapest, Hungary.
| | - Beáta Kerémi
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Erzsébet Bori
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Anna Földes
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| |
Collapse
|
26
|
Snead ML. Biomineralization of a self-assembled-, soft-matrix precursor: Enamel. JOM (WARRENDALE, PA. : 1989) 2015; 67:788-795. [PMID: 26052186 PMCID: PMC4454482 DOI: 10.1007/s11837-015-1305-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Enamel is the bioceramic covering of teeth, a composite tissue composed of hierarchical organized hydroxyapatite crystallites fabricated by cells under physiologic pH and temperature. Enamel material properties resist wear and fracture to serve a lifetime of chewing. Understanding the cellular and molecular mechanisms for enamel formation may allow a biology-inspired approach to material fabrication based on self-assembling proteins that control form and function. Genetic understanding of human diseases expose insight from Nature's errors by exposing critical fabrication events that can be validated experimentally and duplicated in mice using genetic engineering to phenocopy the human disease so that it can be explored in detail. This approach led to assessment of amelogenin protein self-assembly which, when altered, disrupts fabrication of the soft enamel protein matrix. A misassembled protein matrix precursor results in loss of cell to matrix contacts essential to fabrication and mineralization.
Collapse
Affiliation(s)
- Malcolm L Snead
- Center for Craniofacial Molecular Biology Hermann Ostrow School of Dentistry of USC The University of Southern California 2250 Alcazar St., CSA Room 142, HSC Los Angeles, CA 90032
| |
Collapse
|
27
|
Wen X, Lacruz RS, Paine ML. Dental and Cranial Pathologies in Mice Lacking the Cl(-) /H(+) -Exchanger ClC-7. Anat Rec (Hoboken) 2015; 298:1502-8. [PMID: 25663454 DOI: 10.1002/ar.23118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 12/01/2014] [Accepted: 12/05/2014] [Indexed: 11/10/2022]
Abstract
ClC-7 is a 2Cl(-) /1H(+) -exchanger expressed at late endosomes and lysosomes, as well as the ruffled border of osteoclasts. ClC-7 deficiencies in mice and humans lead to impaired osteoclast function and therefore osteopetrosis. Failure of tooth eruption is also apparent in ClC-7 mutant animals, and this has been attributed to the osteoclast dysfunction and the subsequent defect in alveolar bone resorptive activity surrounding tooth roots. Ameloblasts also express ClC-7, and this study aims to determine the significance of ClC-7 in enamel formation by examining the dentitions of ClC-7 mutant mice. Micro-CT analysis revealed that the molar teeth of 3-week old ClC-7 mutant mice had no roots, and the incisors were smaller than their age-matched controls. Despite these notable developmental differences, the enamel and dentin densities of the mutant mice were comparable to those of the wild-type littermates. Scanning electron microscopy showed normal enamel crystallite and prismatic organization in the ClC-7 mutant mice, although the enamel was thinner (hypoplastic) than in controls. These results suggested that ClC-7 was not critical to enamel and dentin formation, and the observed tooth defects may be related more to a resulting alveolar bone phenotype. Micro-CT analysis also revealed abnormal features in the calvarial bones of the mutant mice. The cranial sutures in ClC-7 mutant mice remained open compared to the closed sutures seen in the control mice at 3 weeks. These data demonstrate that ClC-7 deficiency impacts the development of the dentition and calvaria, but does not significantly disrupt amelogenesis.
Collapse
Affiliation(s)
- Xin Wen
- Herman Ostrow School of Dentistry of USC, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, USA
| | - Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York, USA
| | - Michael L Paine
- Herman Ostrow School of Dentistry of USC, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, USA
| |
Collapse
|
28
|
Yang T, Zhang Y, Zheng D, Hao Y, Snead ML, Duan X. High-fluoride promoted phagocytosis-induced apoptosis in a matured ameloblast-like cell line. Arch Oral Biol 2015; 60:84-90. [PMID: 25260155 PMCID: PMC4469496 DOI: 10.1016/j.archoralbio.2014.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/30/2014] [Accepted: 09/09/2014] [Indexed: 12/23/2022]
Abstract
Endocytosis and phagocytosis are important physiologic activities occurring during ameloblast differentiation. We have previously found that excess fluoride inhibited ameloblasts endocytotic functions. Here, we hypothesized that increasing amounts of fluoride may affect ameloblast phagocytotic function during their differentiation. Using cell culture, we first induced maturation of the mouse ameloblast-like LS8 cells by treatment with exogenous retinoic acid (RA) and dexamethasone (DEX). We measured their phagocytotic activity by fluorescent microscopy using a live cell visualization station. We found that ameloblast-like LS8 cells matured with RA/DEX treatment and the increasing amounts of fluoride demonstrated the up-regulated expression of the phagocytotic marker proteins, LAMP1 and CD68. A connection between phagocytosis and apoptosis was confirmed by the increased number of phagocytotic vacuole-like structures and the heterochromatin margination phenomenon observed in the RA/DEX with NaF treatment group. The increase in albumin uptake by ameloblasts was confirmed using whole organ culture of incisor tooth germs. Here, in fluoride treated tooth germs, mature canonical ameloblasts showed greater amounts of albumin uptake, which was accompanied by decreased expression of the anti-apoptosis marker, Bcl-2 along with up-regulated expression of CD68. From these observations, we inferred that high doses of fluoride may cause apoptosis by increasing the phagocytosis of protein particles in mature-stage ameloblasts and loss of Bcl-2 signals might be involved in this process.
Collapse
Affiliation(s)
- Ting Yang
- State Key Laboratory of Military Stomatology, Department of Oral Biology, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, Shaanxi 710032, PR China
| | - Yanli Zhang
- State Key Laboratory of Military Stomatology, Department of Oral Biology, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, Shaanxi 710032, PR China
| | - Dongdong Zheng
- State Key Laboratory of Military Stomatology, Department of Oral Biology, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, Shaanxi 710032, PR China
| | - Ying Hao
- State Key Laboratory of Military Stomatology, Department of Oral Biology, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, Shaanxi 710032, PR China
| | - Malcolm L Snead
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, CSA 142, Health Sciences Campus, Herman Ostrow School of Dentistry of USC, University of Southern California, 2250 Alcazar Street, Los Angeles, CA 90033, United States
| | - Xiaohong Duan
- State Key Laboratory of Military Stomatology, Department of Oral Biology, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, Shaanxi 710032, PR China.
| |
Collapse
|
29
|
He J, Liu H, Wu C. Identification of SCARA3, SCARA5 and MARCO of class A scavenger receptor-like family in Pseudosciaena crocea. FISH & SHELLFISH IMMUNOLOGY 2014; 41:238-249. [PMID: 25218683 DOI: 10.1016/j.fsi.2014.07.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/14/2014] [Accepted: 07/25/2014] [Indexed: 06/03/2023]
Abstract
The class A scavenger receptors are important pattern recognition receptors of the innate immune system in living organisms. According to the whole-genome data of large yellow croaker (Pseudosciaena crocea), three kinds of scavenger receptors, SCARA3, SCARA5 and MARCO were cloned from the spleen, designated severally as TycSA3, TycSA5 and TycMAC. The complete cDNAs open reading frames (ORF) of TycSA3, TycSA5 and TycMAC were 1938 bp, 1677 bp and 1218 bp (GenBank accession no. KJ467772, KJ467773 and KJ467771), encoding 645, 558 and 405 amino acid (aa) residues respectively. The BLASTp analysis strongly suggested that the sequences shared high similarity with known SCARA3, SCARA5 and MARCO. The phylogenetic relationship analysis illustrated that different subtype of SRs formed their own separate branches, TycSA3 and TycSA5 were placed in SCARA3 and SCARA5 branch of Osteichthyes fish respectively with strong bootstrap support. Curiously, the TycMAC was clustered with Alligator sinensis. ClustalW analysis with amino acid sequences revealed that the proportion of identity with other species was 59-71% for TycSA3 and 55-72% for TycSA5, but the scale of TycMAC was considerable lower than those of other two genes (only approximately 38%). The SR family motifs, such as transmembrane helix region, colied coli region and collagens region in the TycSA3, TycSA5 and TycMAC were conserved. There was an optional cysteine-rich (SRCR) domain (from 457 to 557 residues) containing 6 conserved cysteines (C-482, C-495, C-526, C-536, C-546 and C-556) in TycSA5. Likewise, the SRCR domains of TycMAC (from 310 to 405 residues) also contained C-333, C-346, C-374, C-384, C-394 and C-404 cysteines residues. Particularly, there were the major TRAF2-binding consensus motif and two main motifs on internalization of receptor in TycSA3 and TycSA5. The gene structures of different species were analyzed with GeneMaper v2.5, and the number of introns and exons of TycSA3, TycSA5 and TycMAC in DNA sequences were different, for example some corresponding exon regions were divided into several smaller exon portions. Furthermore, quantitative real-time PCR (qRT-PCR) analysis indicated the highest mRNA expression of TycSA3, TycSA5 and TycMAC all appeared in spleen among eight detected tissues, and the expression of them were up-regulated in spleen after Vibrio alginolyticus injection. All these results demonstrated that class A SRs played a significant role in the defense against pathogenic bacteria infection in innate immune of sciaenidae fish.
Collapse
Affiliation(s)
- Jianyu He
- National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan 316022, PR China
| | - Huihui Liu
- National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan 316022, PR China
| | - Changwen Wu
- National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan 316022, PR China.
| |
Collapse
|
30
|
Yin K, Hacia JG, Zhong Z, Paine ML. Genome-wide analysis of miRNA and mRNA transcriptomes during amelogenesis. BMC Genomics 2014; 15:998. [PMID: 25406666 PMCID: PMC4254193 DOI: 10.1186/1471-2164-15-998] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 10/23/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND In the rodent incisor during amelogenesis, as ameloblast cells transition from secretory stage to maturation stage, their morphology and transcriptome profiles change dramatically. Prior whole genome transcriptome analysis has given a broad picture of the molecular activities dominating both stages of amelogenesis, but this type of analysis has not included miRNA transcript profiling. In this study, we set out to document which miRNAs and corresponding target genes change significantly as ameloblasts transition from secretory- to maturation-stage amelogenesis. RESULTS Total RNA samples from both secretory- and maturation-stage rat enamel organs were subjected to genome-wide miRNA and mRNA transcript profiling. We identified 59 miRNAs that were differentially expressed at the maturation stage relative to the secretory stage of enamel development (False Discovery Rate (FDR)<0.05, fold change (FC)≥1.8). In parallel, transcriptome profiling experiments identified 1,729 mRNA transcripts that were differentially expressed in the maturation stage compared to the secretory stage (FDR<0.05, FC≥1.8). Based on bioinformatics analyses, 5.8% (629 total) of these differentially expressed genes (DEGS) were highlighted as being the potential targets of 59 miRNAs that were differentially expressed in the opposite direction, in the same tissue samples. Although the number of predicted target DEGs was not higher than baseline expectations generated by examination of stably expressed miRNAs, Gene Ontology (GO) analysis showed that these 629 DEGS were enriched for ion transport, pH regulation, calcium handling, endocytotic, and apoptotic activities. Seven differentially expressed miRNAs (miR-21, miR-31, miR-488, miR-153, miR-135b, miR-135a and miR298) in secretory- and/or maturation-stage enamel organs were confirmed by in situ hybridization. Further, we used luciferase reporter assays to provide evidence that two of these differentially expressed miRNAs, miR-153 and miR-31, are potential regulators for their predicated target mRNAs, Lamp1 (miR-153) and Tfrc (miR-31). CONCLUSIONS In conclusion, these data indicate that miRNAs exhibit a dynamic expression pattern during the transition from secretory-stage to maturation-stage tooth enamel formation. Although they represent only one of numerous mechanisms influencing gene activities, miRNAs specific to the maturation stage could be involved in regulating several key processes of enamel maturation by influencing mRNA stability and translation.
Collapse
Affiliation(s)
- Kaifeng Yin
- />Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, CSA103, Los Angeles, CA 90033 USA
| | - Joseph G Hacia
- />Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSA140, Los Angeles, CA 90033 USA
| | - Zhe Zhong
- />Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, CSA103, Los Angeles, CA 90033 USA
| | - Michael L Paine
- />Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, CSA103, Los Angeles, CA 90033 USA
| |
Collapse
|
31
|
Katsura KA, Horst JA, Chandra D, Le TQ, Nakano Y, Zhang Y, Horst OV, Zhu L, Le MH, DenBesten PK. WDR72 models of structure and function: a stage-specific regulator of enamel mineralization. Matrix Biol 2014; 38:48-58. [PMID: 25008349 PMCID: PMC4185229 DOI: 10.1016/j.matbio.2014.06.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 06/21/2014] [Accepted: 06/26/2014] [Indexed: 12/18/2022]
Abstract
Amelogenesis Imperfecta (AI) is a clinical diagnosis that encompasses a group of genetic mutations, each affecting processes involved in tooth enamel formation and thus, result in various enamel defects. The hypomaturation enamel phenotype has been described for mutations involved in the later stage of enamel formation, including Klk4, Mmp20, C4orf26, and Wdr72. Using a candidate gene approach we discovered a novel Wdr72 human mutation in association with AI to be a 5-base pair deletion (c.806_810delGGCAG; p.G255VfsX294). To gain insight into the function of WDR72, we used computer modeling of the full-length human WDR72 protein structure and found that the predicted N-terminal sequence forms two beta-propeller folds with an alpha-solenoid tail at the C-terminus. This domain iteration is characteristic of vesicle coat proteins, such as beta'-COP, suggesting a role for WDR72 in the formation of membrane deformation complexes to regulate intracellular trafficking. Our Wdr72 knockout mouse model (Wdr72(-/-)), containing a LacZ reporter knock-in, exhibited hypomineralized enamel similar to the AI phenotype observed in humans with Wdr72 mutations. MicroCT scans of Wdr72(-/-) mandibles affirmed the hypomineralized enamel phenotype occurring at the onset of the maturation stage. H&E staining revealed a shortened height phenotype in the Wdr72(-/-) ameloblasts with retained proteins in the enamel matrix during maturation stage. H(+)/Cl(-) exchange transporter 5 (CLC5), an early endosome acidifier, was co-localized with WDR72 in maturation-stage ameloblasts and decreased in Wdr72(-/-) maturation-stage ameloblasts. There were no obvious differences in RAB4A and LAMP1 immunostaining of Wdr72(-/-) mice as compared to wildtype controls. Moreover, Wdr72(-/-) ameloblasts had reduced amelogenin immunoreactivity, suggesting defects in amelogenin fragment resorption from the matrix. These data demonstrate that WDR72 has a major role in enamel mineralization, most notably during the maturation stage, and suggest a function involving endocytic vesicle trafficking, possibly in the removal of amelogenin proteins.
Collapse
Affiliation(s)
- K A Katsura
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| | - J A Horst
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| | - D Chandra
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| | - T Q Le
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| | - Y Nakano
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| | - Y Zhang
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| | - O V Horst
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| | - L Zhu
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| | - M H Le
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| | - P K DenBesten
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0422, USA
| |
Collapse
|
32
|
Sarkar J, Simanian EJ, Tuggy SY, Bartlett JD, Snead ML, Sugiyama T, Paine ML. Comparison of two mouse ameloblast-like cell lines for enamel-specific gene expression. Front Physiol 2014; 5:277. [PMID: 25120490 PMCID: PMC4110967 DOI: 10.3389/fphys.2014.00277] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 07/07/2014] [Indexed: 12/20/2022] Open
Abstract
Ameloblasts are ectoderm-derived cells that produce an extracellular enamel matrix that mineralizes to form enamel. The development and use of immortalized cell lines, with a stable phenotype, is an important contribution to biological studies as it allows for the investigation of molecular activities without the continuous need for animals. In this study we compare the expression profiles of enamel-specific genes in two mouse derived ameloblast-like cell lines: LS8 and ALC cells. Quantitative PCR analysis indicates that, relative to each other, LS8 cells express greater mRNA levels for genes that define secretory-stage activities (Amelx, Ambn, Enam, and Mmp20), while ALC express greater mRNA levels for genes that define maturation-stage activities (Odam and Klk4). Western blot analyses show that Amelx, Ambn, and Odam proteins are detectable in ALC, but not LS8 cells. Unstimulated ALC cells form calcified nodules, while LS8 cells do not. These data provide greater insight as to the suitability of both cell lines to contribute to biological studies on enamel formation and biomineralization, and highlight some of the strengths and weaknesses when relying on enamel epithelial organ-derived cell lines to study molecular activities of amelogenesis.
Collapse
Affiliation(s)
- Juni Sarkar
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry of USC, University of Southern California Los Angeles, CA, USA
| | - Emil J Simanian
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry of USC, University of Southern California Los Angeles, CA, USA
| | - Sarah Y Tuggy
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry of USC, University of Southern California Los Angeles, CA, USA
| | - John D Bartlett
- Department of Mineralized Tissue Biology, The Forsyth Institute Cambridge, MA, USA
| | - Malcolm L Snead
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry of USC, University of Southern California Los Angeles, CA, USA
| | - Toshihiro Sugiyama
- Department of Biochemistry, Akita University Graduate School of Medicine Hondo, Akita, Japan
| | - Michael L Paine
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry of USC, University of Southern California Los Angeles, CA, USA
| |
Collapse
|
33
|
Abstract
The biological functions of ion channels in tooth development vary according to the nature of their gating, the species of ions passing through those gates, the number of gates, localization of channels, tissue expressing the channel, and interactions between cells and microenvironment. Ion channels feature unique and specific ion flux in ameloblasts, odontoblasts, and other tooth-specific cell lineages. Both enamel and dentin have active chemical systems orchestrating a variety of ion exchanges and demineralization and remineralization processes in a stage-dependent manner. An important role for ion channels is to regulate and maintain the calcium and pH homeostasis that are critical for proper enamel and dentin biomineralization. Specific functions of chloride channels, TRPVs, calcium channels, potassium channels, and solute carrier superfamily members in tooth formation have been gradually clarified in recent years. Mutations in these ion channels or transporters often result in disastrous changes in tooth development. The channelopathies of tooth include altered eruption (CLCN7, KCNJ2, TRPV3), root dysplasia (CLCN7, KCNJ2), amelogenesis imperfecta (KCNJ1, CFTR, AE2, CACNA1C, GJA1), dentin dysplasia (CLCN5), small teeth (CACNA1C, GJA1), tooth agenesis (CLCN7), and other impairments. The mechanisms leading to tooth channelopathies are primarily related to pH regulation, calcium homeostasis, or other alterations of the niche for tooth eruption and development.
Collapse
Affiliation(s)
- X Duan
- Department of Oral Biology, Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, The Fourth Military Medical University, Xi'an, 710032, P.R. China
| |
Collapse
|
34
|
Bronckers ALJJ, Gueneli N, Lüllmann-Rauch R, Schneppenheim J, Moraru AP, Himmerkus N, Bervoets TJ, Fluhrer R, Everts V, Saftig P, Schröder B. The intramembrane protease SPPL2A is critical for tooth enamel formation. J Bone Miner Res 2013; 28:1622-30. [PMID: 23426979 DOI: 10.1002/jbmr.1895] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/06/2013] [Accepted: 02/11/2013] [Indexed: 12/15/2022]
Abstract
Intramembrane proteases are critically involved in signal transduction and membrane protein turnover. Signal-peptide-peptidase-like 2a (SPPL2A), a presenilin-homologue residing in lysosomes/late endosomes, cleaves type II-oriented transmembrane proteins. We recently identified SPPL2A as the enzyme controlling turnover and functions of the invariant chain (CD74) of the major histocompatibility complex II (MHCII) and demonstrated critical importance of this process for B cell development. Surprisingly, we found that SPPL2A is critical for formation of dental enamel. In Sppl2a knockout mice, enamel of the erupted incisors was chalky white and rapidly eroded after eruption. SPPL2A was found to be expressed in enamel epithelium during secretory and maturation stage amelogenesis. Mineral content of enamel in Sppl2a⁻/⁻ incisors was inhomogeneous and reduced by ∼20% compared to wild-type mice with the most pronounced reduction at the mesial side. Frequently, disruption of the enamel layer and localized detachment of the most superficial enamel layer was observed in the knockout incisors leading to an uneven enamel surface. In Sppl2a null mice, morphology and function of secretory stage ameloblasts were not noticeably different from that of wild-type mice. However, maturation stage ameloblasts showed reduced height and a characteristic undulation of the ameloblast layer with localized adherence of the cells to the outer enamel. This was reflected in a delayed and incomplete resorption of the proteinaceous enamel matrix. Thus, we conclude that intramembrane proteolysis by SPPL2A is essential for maintaining cellular homeostasis of ameloblasts. Because modulation of SPPL2A activity appears to be an attractive therapeutic target to deplete B cells and treat autoimmunity, interference with tooth enamel formation should be investigated as a possible adverse effect of pharmacological SPPL2A inhibitors in humans.
Collapse
|
35
|
Wen X, Paine ML. Iron deposition and ferritin heavy chain (Fth) localization in rodent teeth. BMC Res Notes 2013; 6:1. [PMID: 23281703 PMCID: PMC3556315 DOI: 10.1186/1756-0500-6-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 12/18/2012] [Indexed: 05/12/2023] Open
Abstract
Background An iron rich layer on the labial surface is characteristic of the enamel of rodent incisors. In order to address a role for iron content in continuously growing incisors during odontogenesis, we studied iron deposition patterns in enamel and dentine using Perls’ blue staining and ferritin heavy chain (Fth) immunolocalization. Fth expression is regulated by iron level; therefore its localization can be used as a sensitive indicator for iron deposition. Results Sagittal sections of 4-week old rat incisors showed a gradual increase in iron level in the enamel organ from secretory to maturation stages. In addition, iron was detected in ameloblasts of erupting third molars of 4-week old rats, suggesting iron plays a role in both incisor and molar development. In odontoblasts, the presence of iron was demonstrated, and this is consistent with iron’s role in collagen synthesis. Using postnatal 3-, 6-, 9-day old mice, the spatial and temporal expression of Fth in tooth development again indicated the presence of iron in mature ameloblasts and odontoblasts. Conclusions While these data do not explain what functional role iron has in tooth formation, it does highlight a significant molecular activity associated with the formation of the rodent dentition.
Collapse
Affiliation(s)
- Xin Wen
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, USA
| | | |
Collapse
|
36
|
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.
Collapse
Affiliation(s)
- R S Lacruz
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA.
| | | | | | | | | |
Collapse
|