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Liao C, Liang S, Wang Y, Zhong T, Liu X. Sclerostin is a promising therapeutic target for oral inflammation and regenerative dentistry. J Transl Med 2022; 20:221. [PMID: 35562828 PMCID: PMC9102262 DOI: 10.1186/s12967-022-03417-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/28/2022] [Indexed: 11/10/2022] Open
Abstract
Sclerostin is the protein product of the SOST gene and is known for its inhibitory effects on bone formation. The monoclonal antibody against sclerostin has been approved as a novel treatment method for osteoporosis. Oral health is one of the essential aspects of general human health. Hereditary bone dysplasia syndrome caused by sclerostin deficiency is often accompanied by some dental malformations, inspiring the therapeutic exploration of sclerostin in the oral and dental fields. Recent studies have found that sclerostin is expressed in several functional cell types in oral tissues, and the expression level of sclerostin is altered in pathological conditions. Sclerostin not only exerts similar negative outcomes on the formation of alveolar bone and bone-like tissues, including dentin and cementum, but also participates in the development of oral inflammatory diseases such as periodontitis, pulpitis, and peri-implantitis. This review aims to highlight related research progress of sclerostin in oral cavity, propose necessary further research in this field, and discuss its potential as a therapeutic target for dental indications and regenerative dentistry.
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Affiliation(s)
- Chufang Liao
- School of Stomatology, Jinan University, Guangzhou, China.,Clinical Research Platform for Interdiscipline of Stomatology, Jinan University, Guangzhou, China.,Department of Stomatology Medical Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Shanshan Liang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.,Department of Prosthodontics, Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yining Wang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.,Department of Prosthodontics, Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Ting Zhong
- School of Stomatology, Jinan University, Guangzhou, China.,Clinical Research Platform for Interdiscipline of Stomatology, Jinan University, Guangzhou, China.,Department of Stomatology Medical Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Xiangning Liu
- School of Stomatology, Jinan University, Guangzhou, China. .,Clinical Research Platform for Interdiscipline of Stomatology, Jinan University, Guangzhou, China. .,Department of Stomatology Medical Center, The First Affiliated Hospital of Jinan University, Guangzhou, China.
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2
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Son YB, Kang YH, Lee HJ, Jang SJ, Bharti D, Lee SL, Jeon BG, Park BW, Rho GJ. Evaluation of odonto/osteogenic differentiation potential from different regions derived dental tissue stem cells and effect of 17β-estradiol on efficiency. BMC Oral Health 2021; 21:15. [PMID: 33413268 PMCID: PMC7792121 DOI: 10.1186/s12903-020-01366-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
Background The dentin is a tissue, which is formed by odontoblasts at the pulp interface of the teeth that supports the enamel. Odontoblasts, the cranial neural crest cells are derived from ectodermal mesenchymal stem cells (MSCs) and are long and polarized cells. They are present at the outer surface of dentin and play a prominent role about dentin formation. Recently, attention has been focused on induction of odontoblast using various type of MSCs and effects of the 17ß-estradiol supplementation. In this study, we establish an efficient odonto/osteoblast differentiation protocol using 17ß-estradiol supplementation while comparing the odonto/osteoblast ability of various dental MSCs. Methods Same donor derived four types of dental MSCs namely dental pulp stem cells (DPSCs), stem cells from apical papilla (SCAP), dental follicle stem cells (DFSCs), and periodontal ligament stem cells (PDLSCs) were evaluated for their stemness characteristics and potency towards odonto/osteoblast (Induced odonto/osteoblast) differentiation.
Then 17ß-estradiol supplementation of 0 and 10 µM was applied to the odonto/osteoblast differentiation media for 14 days respectively. Furthermore, mRNA and protein levels of odonto/osteoblast markers were evaluated. Results All of the experimental groups displayed stemness characteristics by showing adipocyte and chondrocyte differentiation abilities, expression for cell surface markers and cell proliferation capacity without any significant differences. Moreover, all dental derived MSCs were shown to have odonto/osteoblast differentiation ability when cultured under specific conditions and also showed positive expression for odontoblast markers at both mRNA and protein level. Among all, DPSCs revealed the higher differentiation potential than other dental MSCs. Furthermore, odonto/osteoblast differentiation potential was enhanced by supplementing the differentiation media with 17ß-estradiol (E2). Conclusions Thus, DPSCs possess higher odonto/osteogenic potential than the SCAPs, DFSCs, PDLSCs and their differentiation capacity can by further enhanced under E2 supplementation.
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Affiliation(s)
- Young-Bum Son
- Department of Theriogenology and Biotechnology, College of Veterinary Medicine and Research Institute of Life Science, Gyeongsang National University, 501 Jinju-daero, Jinju, GN, 660-701, Republic of Korea
| | - Young-Hoon Kang
- Department of Oral and Maxillofacial Surgery, Changwon Gyeongsang National University Hospital, Changwon, Republic of Korea.,Department of Oral and Maxillofacial Surgery, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - Hyeon-Jeong Lee
- Department of Theriogenology and Biotechnology, College of Veterinary Medicine and Research Institute of Life Science, Gyeongsang National University, 501 Jinju-daero, Jinju, GN, 660-701, Republic of Korea
| | - Si-Jung Jang
- Department of Theriogenology and Biotechnology, College of Veterinary Medicine and Research Institute of Life Science, Gyeongsang National University, 501 Jinju-daero, Jinju, GN, 660-701, Republic of Korea
| | - Dinesh Bharti
- Department of Theriogenology and Biotechnology, College of Veterinary Medicine and Research Institute of Life Science, Gyeongsang National University, 501 Jinju-daero, Jinju, GN, 660-701, Republic of Korea
| | - Sung-Lim Lee
- Department of Theriogenology and Biotechnology, College of Veterinary Medicine and Research Institute of Life Science, Gyeongsang National University, 501 Jinju-daero, Jinju, GN, 660-701, Republic of Korea
| | - Byeong-Gyun Jeon
- Department of Biology Education, Gyeongsang National University, Jinju, Republic of Korea
| | - Bong-Wook Park
- Department of Oral and Maxillofacial Surgery, Changwon Gyeongsang National University Hospital, Changwon, Republic of Korea. .,Department of Oral and Maxillofacial Surgery, Gyeongsang National University School of Medicine, Jinju, Republic of Korea. .,Department of Dentistry, Hanil Hospital, Jinju, Republic of Korea.
| | - Gyu-Jin Rho
- Department of Theriogenology and Biotechnology, College of Veterinary Medicine and Research Institute of Life Science, Gyeongsang National University, 501 Jinju-daero, Jinju, GN, 660-701, Republic of Korea.
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3
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Kim JH, Won J, Oh SB. Expression of Ca V3.1 T-type Calcium Channels in Acutely Isolated Adult Rat Odontoblasts. Arch Oral Biol 2020; 118:104864. [PMID: 32847753 DOI: 10.1016/j.archoralbio.2020.104864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 03/20/2020] [Accepted: 07/30/2020] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Odontoblasts, which consist the outermost compartment of the dental pulp, are primarily engaged in dentin formation. Earlier evidence suggests that voltage-gated calcium channels, such as the high voltage-activated L-type calcium channels, serve as a calcium entry route to mediate dentin formation in odontoblasts. However, the involvement of other voltage-gated calcium channels in regulating intracellular Ca2+ remain unanswered. DESIGN The expression of voltage-gated calcium channel subtypes of the P/Q- (CaV2.1), N-(CaV2.2), R- (CaV2.3), and T- (CaV3.1-3.3) type were screened in adult rat odontoblasts by single cell RT-PCR. Among these candidates, immunopositivity against CaV3.1 was examined in the odontoblastic layer in teeth sections and dissociated odontoblasts. To confirm the functional expression of CaV3.1 in odontoblasts, intracellular Ca2+ increase in response to membrane depolarization was monitored with Fura-2-based ratiometric calcium imaging. RESULTS Among the candidate calcium channels, we found that mRNA for CaV3.1 is mainly detected in odontoblasts, with its expression being detected in the odontoblastic layer and dissociated odontoblasts. High extracellular K+-induced membrane depolarization was inhibited by pharmacological blockers for T-type calcium channels such as amiloride or ML218. CONCLUSION Our results demonstrate that among P/Q-, N-, R-, and T-type calcium channels, CaV3.1 is mainly expressed in odontoblasts to mediate intracellular Ca2+ signaling in response to membrane depolarization. These findings suggest that CaV3.1 may facilitate intracellular Ca2+ dynamics especially in the range of subliminal depolarizations near resting membrane potentials where other high voltage-gated calcium channels such as the L-type are likely to be inactive.
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Affiliation(s)
- Ji Hyun Kim
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Jonghwa Won
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Seog Bae Oh
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea; Dental Research Institute and Department of Neurobiology & Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
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4
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Reibring CG, Hallberg K, Linde A, Gritli-Linde A. Distinct and Overlapping Expression Patterns of the Homer Family of Scaffolding Proteins and Their Encoding Genes in Developing Murine Cephalic Tissues. Int J Mol Sci 2020; 21:ijms21041264. [PMID: 32070057 PMCID: PMC7072945 DOI: 10.3390/ijms21041264] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/08/2020] [Accepted: 02/10/2020] [Indexed: 02/06/2023] Open
Abstract
In mammals Homer1, Homer2 and Homer3 constitute a family of scaffolding proteins with key roles in Ca2+ signaling and Ca2+ transport. In rodents, Homer proteins and mRNAs have been shown to be expressed in various postnatal tissues and to be enriched in brain. However, whether the Homers are expressed in developing tissues is hitherto largely unknown. In this work, we used immunohistochemistry and in situ hybridization to analyze the expression patterns of Homer1, Homer2 and Homer3 in developing cephalic structures. Our study revealed that the three Homer proteins and their encoding genes are expressed in a wide range of developing tissues and organs, including the brain, tooth, eye, cochlea, salivary glands, olfactory and respiratory mucosae, bone and taste buds. We show that although overall the three Homers exhibit overlapping distribution patterns, the proteins localize at distinct subcellular domains in several cell types, that in both undifferentiated and differentiated cells Homer proteins are concentrated in puncta and that the vascular endothelium is enriched with Homer3 mRNA and protein. Our findings suggest that Homer proteins may have differential and overlapping functions and are expected to be of value for future research aiming at deciphering the roles of Homer proteins during embryonic development.
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Affiliation(s)
- Claes-Göran Reibring
- Department of Oral Biochemistry, Institute of Odontology, Sahlgrenska Academy at the University of Gothenburg, SE-40530 Göteborg, Sweden; (C.-G.R.); (K.H.); (A.L.)
- Public Dental Service, Region Västra Götaland, SE-45131 Uddevalla, Sweden
| | - Kristina Hallberg
- Department of Oral Biochemistry, Institute of Odontology, Sahlgrenska Academy at the University of Gothenburg, SE-40530 Göteborg, Sweden; (C.-G.R.); (K.H.); (A.L.)
| | - Anders Linde
- Department of Oral Biochemistry, Institute of Odontology, Sahlgrenska Academy at the University of Gothenburg, SE-40530 Göteborg, Sweden; (C.-G.R.); (K.H.); (A.L.)
| | - Amel Gritli-Linde
- Department of Oral Biochemistry, Institute of Odontology, Sahlgrenska Academy at the University of Gothenburg, SE-40530 Göteborg, Sweden; (C.-G.R.); (K.H.); (A.L.)
- Correspondence: ; Tel.: +46-31-7863392
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5
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Lee K, Lee BM, Park CK, Kim YH, Chung G. Ion Channels Involved in Tooth Pain. Int J Mol Sci 2019; 20:ijms20092266. [PMID: 31071917 PMCID: PMC6539952 DOI: 10.3390/ijms20092266] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/03/2019] [Accepted: 05/03/2019] [Indexed: 01/05/2023] Open
Abstract
The tooth has an unusual sensory system that converts external stimuli predominantly into pain, yet its sensory afferents in teeth demonstrate cytochemical properties of non-nociceptive neurons. This review summarizes the recent knowledge underlying this paradoxical nociception, with a focus on the ion channels involved in tooth pain. The expression of temperature-sensitive ion channels has been extensively investigated because thermal stimulation often evokes tooth pain. However, temperature-sensitive ion channels cannot explain the sudden intense tooth pain evoked by innocuous temperatures or light air puffs, leading to the hydrodynamic theory emphasizing the microfluidic movement within the dentinal tubules for detection by mechanosensitive ion channels. Several mechanosensitive ion channels expressed in dental sensory systems have been suggested as key players in the hydrodynamic theory, and TRPM7, which is abundant in the odontoblasts, and recently discovered PIEZO receptors are promising candidates. Several ligand-gated ion channels and voltage-gated ion channels expressed in dental primary afferent neurons have been discussed in relation to their potential contribution to tooth pain. In addition, in recent years, there has been growing interest in the potential sensory role of odontoblasts; thus, the expression of ion channels in odontoblasts and their potential relation to tooth pain is also reviewed.
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Affiliation(s)
- Kihwan Lee
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 406-799, Korea.
| | - Byeong-Min Lee
- Department of Oral Physiology and Program in Neurobiology, School of Dentistry, Seoul National University, Seoul 08826, Korea.
| | - Chul-Kyu Park
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 406-799, Korea.
| | - Yong Ho Kim
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 406-799, Korea.
| | - Gehoon Chung
- Department of Oral Physiology and Program in Neurobiology, School of Dentistry, Seoul National University, Seoul 08826, Korea.
- Dental Research Institute, Seoul National University, Seoul 03080, Korea.
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6
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An S. The emerging role of extracellular Ca
2+
in osteo/odontogenic differentiation and the involvement of intracellular Ca
2+
signaling: From osteoblastic cells to dental pulp cells and odontoblasts. J Cell Physiol 2018; 234:2169-2193. [DOI: 10.1002/jcp.27068] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/25/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Shaofeng An
- Department of Operative Dentistry and EndodonticsGuanghua School of Stomatology, Hospital of Stomatology, Sun Yat‐sen UniversityGuangzhou China
- Guangdong Province Key Laboratory of StomatologySun Yat‐Sen UniversityGuangzhou China
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7
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Kimura M, Nishi K, Higashikawa A, Ohyama S, Sakurai K, Tazaki M, Shibukawa Y. High pH-Sensitive Store-Operated Ca 2+ Entry Mediated by Ca 2+ Release-Activated Ca 2+ Channels in Rat Odontoblasts. Front Physiol 2018; 9:443. [PMID: 29765331 PMCID: PMC5938338 DOI: 10.3389/fphys.2018.00443] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 04/10/2018] [Indexed: 11/13/2022] Open
Abstract
Odontoblasts play a crucial role in dentin formation and sensory transduction following the application of stimuli to the dentin surface. Various exogenous and endogenous stimuli elicit an increase in the intracellular free calcium concentration ([Ca2+]i) in odontoblasts, which is mediated by Ca2+ release from intracellular Ca2+ stores and/or Ca2+ influx from the extracellular medium. In a previous study, we demonstrated that the depletion of Ca2+ stores in odontoblasts activated store-operated Ca2+ entry (SOCE), a Ca2+ influx pathway. However, the precise biophysical and pharmacological properties of SOCE in odontoblasts have remained unclear. In the present study, we examined the functional expression and pharmacological properties of Ca2+ release-activated Ca2+ (CRAC) channels that mediate SOCE and evaluated the alkali sensitivity of SOCE in rat odontoblasts. In the absence of extracellular Ca2+, treatment with thapsigargin (TG), a sarco/endoplasmic reticulum Ca2+-ATPase inhibitor, induced an increase in [Ca2+]i. After [Ca2+]i returned to near-resting levels, the subsequent application of 2.5 mM extracellular Ca2+ resulted in an increase in [Ca2+]i which is a typical of SOCE activation. Additionally, application of 2-methylthioadenosine diphosphate trisodium salt (2-MeSADP), a P2Y1,12,13 receptor agonist, or carbachol (CCh), a muscarinic cholinergic receptor agonist, in the absence of extracellular Ca2+, induced a transient increase in [Ca2+]i. The subsequent addition of extracellular Ca2+ resulted in significantly higher [Ca2+]i in 2-MeSADP- or CCh-treated odontoblasts than in untreated cells. SOCE, that is activated by addition of extracellular Ca2+ in the TG pretreated odontoblasts was then suppressed by Synta66, BTP2, or lanthanum, which are CRAC channel inhibitors. Treatment with an alkaline solution enhanced SOCE, while treatment with HC030031, a TRPA1 channel antagonist, inhibited it. The amplitude of SOCE at pH 9 in the presence of HC030031 was higher than that at pH 7.4 in the absence of HC030031. These findings indicate that CRAC channel-mediated alkali-sensitive SOCE occurs in odontoblasts. SOCE is mediated by P2Y and muscarinic-cholinergic receptors, which are activated by endogenous ligands in odontoblasts.
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Affiliation(s)
- Maki Kimura
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
| | - Koichi Nishi
- Department of Removable Prosthodontics and Gerodontology, Tokyo Dental College, Tokyo, Japan
| | | | - Sadao Ohyama
- Department of Physiology, Tokyo Dental College, Tokyo, Japan.,Department of Oral Surgery, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Tokyo, Japan
| | - Kaoru Sakurai
- Department of Removable Prosthodontics and Gerodontology, Tokyo Dental College, Tokyo, Japan
| | - Masakazu Tazaki
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
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Zuo J, Zhen J, Wang F, Li Y, Zhou Z. Effect of Low-Intensity Pulsed Ultrasound on the Expression of Calcium Ion Transport-Related Proteins during Tertiary Dentin Formation. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:223-233. [PMID: 29079395 DOI: 10.1016/j.ultrasmedbio.2017.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 08/02/2017] [Accepted: 09/07/2017] [Indexed: 06/07/2023]
Abstract
Low-intensity pulsed ultrasound (LIPUS) is known for its positive effect on bone healing and reparative regeneration. This study investigated whether LIPUS affects reparative progression of the tooth and the expression of calcium ion transport-related proteins in odontoblasts and dental pulp cells using a rat dentin-pulp complex injury model. Forty male adult Sprague-Dawley rats underwent cavity preparation in the right maxillary first molar: 20 received LIPUS irradiation on the cavity-prepared tooth; 20 received LIPUS irradiation on the left maxillary first molar. Rats were randomly allocated into four groups: blank control group, LIPUS group, cavity-prepared group, cavity-prepared + LIPUS group. LIPUS irradiation (frequency: 1.5 MHz, 200-µs pulse width, 1-kHz pulse repetition frequency, 30 mW/cm2 spatial averaged temporal averaged intensity) was administered individually for 20 min daily. Rats were sacrificed 1, 3, 7 and 14 d post-operation. The histopathological and cellular morphologic changes in the dentin-pulp complex were detected with hematoxylin and eosin staining. Expression of calcium ion transport-related proteins (Cav1.2, NCX1 and TRPV1) was determined with immunohistochemical staining and imaging analysis. Histopathological analysis revealed obvious reparative dentin formation at day 14 in the cavity-prepared + LIPUS group compared with the other groups. Expression levels of Cav1.2, NCX1 and TRPV1 increased significantly by 22%, 53% and 23%, respectively, at day 1 and increased significantly by 23%, 27% and 22%, respectively, at day 3 in the cavity-prepared + LIPUS group (p <0.05) compared with the cavity-prepared group. LIPUS has a positive effect on the expression of calcium transport-related proteins during early-stage dentin injury and facilitates tertiary dentin formation; the mechanism for this likely relates to the inflammatory reaction and a mechanical effect.
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Affiliation(s)
- Jing Zuo
- College of Stomatology, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory for Oral Diseases and Biomedical Science, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Jiaxiu Zhen
- College of Stomatology, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory for Oral Diseases and Biomedical Science, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Fei Wang
- College of Stomatology, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory for Oral Diseases and Biomedical Science, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Yueheng Li
- College of Stomatology, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory for Oral Diseases and Biomedical Science, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Zhi Zhou
- College of Stomatology, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory for Oral Diseases and Biomedical Science, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China.
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9
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Kwon M, Baek SH, Park CK, Chung G, Oh SB. Single-cell RT-PCR and immunocytochemical detection of mechanosensitive transient receptor potential channels in acutely isolated rat odontoblasts. Arch Oral Biol 2014; 59:1266-71. [PMID: 25150531 DOI: 10.1016/j.archoralbio.2014.07.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 07/15/2014] [Accepted: 07/19/2014] [Indexed: 01/25/2023]
Abstract
OBJECTIVE Hydrostatic force applied to tooth pulp has long been suspected to be the direct cause of dental pain. However, the molecular and cellular identity of the transducer of the mechanical force in teeth is not clear. Growing number of literatures suggested that odontoblasts, secondary to its primary role as formation of tooth structure, might function as a cellular mechanical transducer in teeth. DESIGN In order to determine whether odontoblasts could play a crucial role in transduction of hydrostatic force applied to dental pulp into electrical impulses, current study investigated the expression of stretch-activated transient receptor potential (TRP) channels in acutely isolated odontoblasts from adult rats by single cell reverse transcriptase polymerase chain reaction and immunocytochemical analysis. RESULTS As the result, expression of TRPM7 (melastatin 7) was observed in majority (87%) of odontoblasts while mRNAs for TRPC1 (canonical 1), TRPC6 (canonical 6) and TRPV4 (vanilloid 4) were detected in small subpopulations of odontoblasts. TRPM3 (melastatin 3) was not detected in our experimental set-up. Immunocytochemical analysis further revealed TRPM7 expression at protein level. CONCLUSION Expression of the mechanosensitive TRP channels provides additional evidence that supports the sensory roles of odontoblasts. Given that TRPM7 is a mechanosensitive ion channel with a kinase activity that plays a role in Mg(2+) homeostasis, it is possible that TRPM7 expressed in odontoblasts might play a central role in mineralization during dentin formation.
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Affiliation(s)
- Minsoo Kwon
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Sang Hoon Baek
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Chul-Kyu Park
- Department of Physiology, Graduate School of Medicine, Gachon University, Incheon 406-799, Republic of Korea
| | - Gehoon Chung
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea; Pain Cognitive Function Research Center, Seoul National University, Seoul, Republic of Korea.
| | - Seog Bae Oh
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea; Pain Cognitive Function Research Center, Seoul National University, Seoul, Republic of Korea; Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea.
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10
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Bleicher F. Odontoblast physiology. Exp Cell Res 2014; 325:65-71. [DOI: 10.1016/j.yexcr.2013.12.012] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/03/2013] [Accepted: 12/08/2013] [Indexed: 11/25/2022]
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11
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Magloire H, Couble ML, Romeas A, Bleicher F. Odontoblast primary cilia: facts and hypotheses. Cell Biol Int 2013; 28:93-9. [PMID: 14984754 DOI: 10.1016/j.cellbi.2003.11.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2003] [Accepted: 11/04/2003] [Indexed: 11/22/2022]
Abstract
Odontoblasts, the cells responsible for the dentine formation, are organized as a single layer of highly polarized and differentiated post-mitotic cells along the interface between the dental pulp and the mineralized tubules. They lay down the physiological secondary dentine throughout the life of the teeth. Odontoblasts play a central role in the transportation of calcium to the dentine and they possibly mediate early stages of sensory processing in teeth. A primary cilium, 9+0 configuration, have been regularly identified in a supra nuclear location. Calbindin D28k has been detected at the base of the cilium membrane. The cilium structure was positive with detyrosinated alpha tubulin antibodies in vivo and in cultured human odontoblasts. Transcripts of tektin, a protein involved in ciliogenesis, were expressed in vitro. The putative role of the primary cilium constituting a critical link between external teeth stimuli and odontoblast responses is extensively discussed.
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Affiliation(s)
- Henry Magloire
- Laboratoire du Développement des tissus dentaires, EA 1892, IFR 62, Faculté d'Odontologie, rue G. Paradin, 69372 Lyon Cedex 08, France.
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12
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Tjäderhane L, Haapasalo M. The dentin-pulp border: a dynamic interface between hard and soft tissues. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1601-1546.2012.00266.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Tsumura M, Sobhan U, Muramatsu T, Sato M, Ichikawa H, Sahara Y, Tazaki M, Shibukawa Y. TRPV1-mediated calcium signal couples with cannabinoid receptors and sodium-calcium exchangers in rat odontoblasts. Cell Calcium 2012; 52:124-36. [PMID: 22656960 DOI: 10.1016/j.ceca.2012.05.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 04/24/2012] [Accepted: 05/02/2012] [Indexed: 11/30/2022]
Abstract
Odontoblasts are involved in the transduction of stimuli applied to exposed dentin. Although expression of thermo/mechano/osmo-sensitive transient receptor potential (TRP) channels has been demonstrated, the properties of TRP vanilloid 1 (TRPV1)-mediated signaling remain to be clarified. We investigated physiological and pharmacological properties of TRPV1 and its functional coupling with cannabinoid (CB) receptors and Na(+)-Ca(2+) exchangers (NCXs) in odontoblasts. Anandamide (AEA), capsaicin (CAP), resiniferatoxin (RF) or low-pH evoked Ca(2+) influx. This influx was inhibited by capsazepine (CPZ). Delay in time-to-activation of TRPV1 channels was observed between application of AEA or CAP and increase in [Ca(2+)](i). In the absence of extracellular Ca(2+), however, an immediate increase in [Ca(2+)](i) was observed on administration of extracellular Ca(2+), followed by activation of TRPV1 channels. Intracellular application of CAP elicited inward current via opening of TRPV1 channels faster than extracellular application. With extracellular RF application, no time delay was observed in either increase in [Ca(2+)](i) or inward current, indicating that agonist binding sites are located on both extra- and intracellular domains. KB-R7943, an NCX inhibitor, yielded an increase in the decay time constant during TRPV1-mediated Ca(2+) entry. Increase in [Ca(2+)](i) by CB receptor agonist, 2-arachidonylglycerol, was inhibited by CB1 receptor antagonist or CPZ, as well as by adenylyl cyclase inhibitor. These results showed that TRPV1-mediated Ca(2+) entry functionally couples with CB1 receptor activation via cAMP signaling. Increased [Ca(2+)](i) by TRPV1 activation was extruded by NCXs. Taken together, this suggests that cAMP-mediated CB1-TRPV1 crosstalk and TRPV1-NCX coupling play an important role in driving cellular functions following transduction of external stimuli to odontoblasts.
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Affiliation(s)
- Maki Tsumura
- Oral Health Science Center hrc8, Tokyo Dental College, Chiba, Japan
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14
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Tsumura M, Okumura R, Tatsuyama S, Ichikawa H, Muramatsu T, Matsuda T, Baba A, Suzuki K, Kajiya H, Sahara Y, Tokuda M, Momose Y, Tazaki M, Shimono M, Shibukawa Y. Ca2+ Extrusion via Na+-Ca2+ Exchangers in Rat Odontoblasts. J Endod 2010; 36:668-74. [DOI: 10.1016/j.joen.2010.01.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 01/06/2010] [Accepted: 01/15/2010] [Indexed: 11/16/2022]
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15
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Magloire H, Couble ML, Thivichon-Prince B, Maurin JC, Bleicher F. Odontoblast: a mechano-sensory cell. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2009; 312B:416-24. [DOI: 10.1002/jez.b.21264] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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16
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Heyeraas KJ, Haug SR, Bukoski RD, Awumey EM. Identification of a Ca2+-sensing receptor in rat trigeminal ganglia, sensory axons, and tooth dental pulp. Calcif Tissue Int 2008; 82:57-65. [PMID: 18175029 DOI: 10.1007/s00223-007-9096-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Accepted: 11/14/2007] [Indexed: 10/22/2022]
Abstract
Extracellular Ca2+ regulates dentin formation, but little information is available on this regulatory mechanism. We have previously reported that sensory denervation reduces dentin formation, suggesting a role for sensory nerves in tooth mineralization. The G protein-coupled Ca2+-sensing receptor (CaR) is expressed in dorsal root ganglia and perivascular sensory nerves in mesenteric arterioles, and activation of these receptors by Ca2+ has been shown to induce vascular relaxation. The present study determined CaR expression in tooth dental pulp (DP), sensory axons, and trigeminal ganglion (TG) as well as the effect of increased [Ca2+]e or a calcimimetic on tooth blood flow. The distribution of CaR, studied by immunochemistry, RT-PCR, and Western blot, indicates abundant expression of CaR in sensory axons in the jaws, TG, and DP. Restriction analysis of PCR products with specific endonucleases showed the presence of CaR message in TG and DP, and Western blotting indicates the expression of mature and immature forms of the receptor in these tissues. Pulpal blood flow, measured by laser-Doppler flowmetry, increased by 67% +/- 6% (n = 12) following receptor stimulation with 5 mM Ca2+, which was completely inhibited by 5 microM IBTx, a high-conductance KCa channel blocker indicating a mechanism involving hyperpolarization. NPS R-467 (10 microM) increased blood flow by 85% +/- 18% (n = 6), suggesting regulation through the CaR. Our results suggest that the CaR is present in sensory nerves, DP, and TG and that an increase in Ca2+ in the DP causes vasodilatation, which may contribute to accumulation of Ca2+ during dentin mineralization.
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Affiliation(s)
- Karin J Heyeraas
- Department of Biomedicine, Section for Physiology, Faculty of Medicine, University of Bergen, Jonas Lies vei 91, N-5009, Bergen, Norway.
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17
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Fan W, Li C, Wang X, Gong N, Xie L, Zhang R. Cloning, characterization and expression analysis of calcium channel β subunit from pearl oyster (Pinctada fucata). J Biosci Bioeng 2007; 104:47-54. [PMID: 17697983 DOI: 10.1263/jbb.104.47] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Accepted: 04/16/2007] [Indexed: 11/17/2022]
Abstract
The absorption, transport and localization of calcium underlie the basis of biomineralization, and Ca(2+) entry into epithelial cell is the primary step in shell formation. However, the related mechanism of Ca(2+) transport is poorly documented at the gene or protein level. L-type voltage-dependent calcium channels may be involved in calcium transport for biomineralization in some marine invertebrates. In this study, a full-length cDNA of a voltage-dependent calcium channel beta subunit from Pinctada fucata (PCabeta) was cloned, and its amino acid sequence was deduced. PCabeta shared 51%-67% apparently sequence identity with voltage-dependent calcium channel beta subunits from other species. However, PCabeta was much shorter than other voltage-dependent calcium channel beta subunits particularly at the carboxyl terminus, indicating that it is likely a truncated beta subunit isoform. Semi-quantitative RT-PCR analysis showed that PCabeta was expressed in all the tested tissues and that it had a higher expression level in the gill tissue and hemolymph than in other tissues, suggesting that L-type voltage-dependent calcium channels are responsible for Ca(2+) absorption in the gill and Ca(2+) entry into hemocytes. In the mantle, PCabeta mRNA was predominantly expressed in the inner and middle folds of the mantle epithelium, suggesting that L-type voltage-dependent calcium channels are involved in Ca(2+) absorption from the ambient medium in the mantle. All these results suggest that voltage-dependent calcium channels are involved in Ca(2+) uptake and transport during oyster biomineralization.
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Affiliation(s)
- Weimin Fan
- Institute of Marine Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China
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18
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Honda MJ, Shinohara Y, Sumita Y, Tonomura A, Kagami H, Ueda M. Shear stress facilitates tissue-engineered odontogenesis. Bone 2006; 39:125-33. [PMID: 16469551 DOI: 10.1016/j.bone.2005.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 10/27/2005] [Accepted: 12/07/2005] [Indexed: 11/27/2022]
Abstract
Numerous studies have demonstrated the effect of shear stress on osteoblasts, but its effect on odontogenic cells has never been reported. In this study, we focused on the effect of shear stress on facilitating tissue-engineered odontogenesis by dissociated single cells. Cells were harvested from the porcine third molar tooth at the early stage of crown formation, and the isolated heterogeneous cells were seeded on a biodegradable polyglycolic acid fiber mesh. Then, cell-polymer constructs with and without exposure to shear stress were evaluated by in vitro and in vivo studies. In in vitro studies, the expression of both epithelial and mesenchymal odontogenic-related mRNAs was significantly enhanced by shear stress for 2 h. At 12 h after exposure to shear stress, the expression of amelogenin, bone sialoprotein and vimentin protein was significantly enhanced compared with that of control. Moreover, after 7 days, alkaline phosphatase activity exhibited a significant increase without any significant effect on cell proliferation in vitro. In vivo, enamel and dentin tissues formed after 15 weeks of in vivo implantation in constructs exposure to in vitro shear stress for 12 h. Such was not the case in controls. We concluded that shear stress facilitates odontogenic cell differentiation in vitro as well as the process of tooth tissue engineering in vivo.
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Affiliation(s)
- M J Honda
- Tooth Regeneration, The Division of Stem Cell Engineering, The Institute of Medical Science, The University of Tokyo, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
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19
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Byers MR, Maeda T, Brown AM, Westenbroek RE. GFAP immunoreactivity and transcription in trigeminal and dental tissues of rats and transgenic GFP/GFAP mice. Microsc Res Tech 2005; 65:295-307. [PMID: 15662620 DOI: 10.1002/jemt.20130] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Sensory mechanisms in teeth are not well understood and may involve pulpal-neural interactions. Tooth cells that proliferate in vitro have polyclonal immunoreactivity (IR) for glial fibrillary acidic protein (GFAP), growth-associated protein (GAP-43), and vimentin, plus glial-like ion channels. Here, we analyzed GFAP-IR patterns in dental and trigeminal tissues of rats, for comparison with green fluorescent protein (GFP) associated with GFAP transcription in transgenic mice, in order to better characterize glial-like cells in dental tissues. Astrocytes, ganglion satellite cells, and epineurial Schwann cells were demonstrated by anti-GFAP antibodies and GFP-GFAP, as expected. Odontoblasts did not stain by any of these methods and cannot be the glial-like cells. Fibroblasts and undifferentiated mesenchymal cells in pulp had polyclonal GFAP-IR and vimentin-IR, while nerve fibers reacted only with polyclonal antibody. Some Schwann cell subtypes in trigeminal nerve and oral mucosa were positive for GFP and for polyclonal anti-GFAP, but not for monoclonal antibody. In pulp almost all Schwann cells were unstained, but many Schwann cells in periodontal ligament had polyclonal GFAP-IR. These results show greater heterogeneity for Schwann cells than expected, and suggest that the glial-like pulp cells are fibroblasts and/or undifferentiated mesenchymal cells or stem cells. We also found that polyclonal GFAP revealed intermediate filaments in preterminal sensory nerve fibers, thereby providing a useful marker for that neural subregion. GFP transcription by some Schwann cell subtypes in oral mucosae and trigeminal nerve, but not trigeminal root was a novel finding that reveals more complexity in peripheral glia than previously recognized.
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Affiliation(s)
- Margaret R Byers
- Anesthesiology, University of Washington, Seattle, Washington 98195, USA.
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20
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Westenbroek RE, Anderson NL, Byers MR. Altered localization of Cav1.2 (L-type) calcium channels in nerve fibers, Schwann cells, odontoblasts, and fibroblasts of tooth pulp after tooth injury. J Neurosci Res 2004; 75:371-83. [PMID: 14743450 DOI: 10.1002/jnr.10863] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have determined the localization of Cav1.2 (L-Type) Ca2+ channels in the cells and nerve fibers in molars of normal or injured rats. We observed high levels of immunostaining of L-type Ca2+ channels in odontoblast cell bodies and their processes, in fibroblast cell bodies and in Schwann cells. Many Cav1.2-containing unmyelinated and myelinated axons were also present in root nerves and proximal branches in coronal pulp, but were usually missing from nerve fibers in dentin. Labeling in the larger fibers was present along the axonal membrane, localized in axonal vesicles, and in nodal regions. After focal tooth injury, there is a marked loss of Cav1.2 channels in injured teeth. Immunostaining of Cav1.2 channels was lost selectively in nerve fibers and local cells of the tooth pulp within 10 min of the lesion, without loss of other Cav channel or pulpal labels. By 60 min, Cav1.2 channels in odontoblasts were detected again but at levels below controls, whereas fibroblasts were labeled well above control levels, similar to upregulation of Cav1.2 channels in astrocytes after injury. By 3 days after the injury, Cav1.2 channels were again detected in nerve fibers and immunostaining of fibroblasts and odontoblasts had returned to control levels. These findings provide new insight into the localization of Cav1.2 channels in dental pulp and sensory fibers, and demonstrate unexpected plasticity of channel distribution in response to nerve injury.
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Affiliation(s)
- R E Westenbroek
- Department of Pharmacology, University of Washington, Seattle, USA.
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21
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Magloire H, Lesage F, Couble ML, Lazdunski M, Bleicher F. Expression and localization of TREK-1 K+ channels in human odontoblasts. J Dent Res 2003; 82:542-5. [PMID: 12821716 DOI: 10.1177/154405910308200711] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
During tooth development, odontoblasts are the cells that form dentin and possibly mediate early stages of sensory processing in teeth. It is suggested that ion channels assist in these events. Indeed, mechanosensitive potassium currents, transducing mechanical stimuli into electrical cell signals, have been previously recorded in the human odontoblast cell membrane. Here, we show by RT-PCR that the mechanosensitive potassium channel TREK-1 (a member of the two-pore-domain potassium channel family) is overexpressed in these cultured cells compared with pulp cells in vitro. In situ hybridization showed that transcripts are detected in the odontoblast layer in vivo. The use of antibodies shows that TREK-1 is strongly expressed in the membrane of coronal odontoblasts and absent in the root. This distribution is related to the spatial distribution of nerve endings identified by labeling of the low-affinity nerve growth factor (NGF) receptor (p75(NTR)). These results demonstrate the expression of TREK-1 in human odontoblasts in vitro and in vivo.
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Affiliation(s)
- H Magloire
- Laboratoire du Développement des Tissus Dentaires, EA 1892, IFR 62, Faculté d'Odontologie, Rue G. Paradin, 69372, Lyon cedex 08, France.
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22
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Shibukawa Y, Suzuki T. Ca2+ signaling mediated by IP3-dependent Ca2+ releasing and store-operated Ca2+ channels in rat odontoblasts. J Bone Miner Res 2003; 18:30-8. [PMID: 12510803 DOI: 10.1359/jbmr.2003.18.1.30] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In the phospholipase-C (PLC) signaling system, Ca2+ is mobilized from intracellular Ca2+ stores by an action of inositol 1,4,5-trisphosphate (IP3). The depletion of IP3-sensitive Ca2+ stores activates a store-operated Ca2+ entry (SOCE). However, no direct evidence has been obtained about these signaling pathways in odontoblasts. In this study, we investigate the characteristics of the SOCE and IP3-mediated Ca2+ mobilizations in rat odontoblasts using fura-2 microfluorometry and a nystatin-perforated patch-clamp technique. In the absence of extracellular Ca2+ ([Ca2+]o), thapsigargin (TG) evoked a transient rise in intracellular Ca2+ concentration ([Ca2+]i). After TG treatment to deplete the store, the subsequent application of Ca2+ resulted in a rapid rise in [Ca2+]i caused by SOCE. In the absence of TG treatment, no SOCE was evoked. The Ca2+ influx was dependent on [Ca2+]o (KD = 1.29 mM) and was blocked by an IP3 receptor inhibitor, 2-aminoethoxydiphenyl borate (2-APB), as well as La3+ in a concentration-dependent manner (IC50 = 26 microM). In TG-treated cells, an elevation of [Ca2+]o from 0 to 2.5 mM elicited an inwardly rectifying current at hyperpolarizing potentials with a positive reversal potential. The currents were selective for Ca2+ over the other divalent cations (Ca2+ > Ba2+ > Sr2+ >> Mn2+). In the absence of [Ca2+]o, carbachol, bradykinin, and 2-methylthioadenosine 5'triphosphate activated Ca2+ release from the store; these were inhibited by 2-APB. These results indicate that odontoblasts possessed Ca2+ signaling pathways through the activation of store-operated Ca2+ channels by the depletion of intracellular Ca2+ stores and through the IP3-induced Ca2+ release activated by PLC-coupled receptors.
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23
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Lundquist P, Ritchie HH, Moore K, Lundgren T, Linde A. Phosphate and calcium uptake by rat odontoblast-like MRPC-1 cells concomitant with mineralization. J Bone Miner Res 2002; 17:1801-13. [PMID: 12369784 DOI: 10.1359/jbmr.2002.17.10.1801] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It has been suggested that odontoblasts are instrumental in translocating Ca2+ and inorganic phosphate (Pi) ions during the mineralization of dentin. The aim of this study was to characterize cellular Pi and Ca2+ uptake in the novel rat odontoblast-like cell line mineralizing rat pulpal cell line (MRPC) 1 during mineralization to see if changes in the ion transport activity would occur as the cultures develop and begin forming a mineralized matrix. MRPC-1 cells were cultured in chemically defined medium containing ascorbate and Pi, and cultures were specifically analyzed for cellular P, and Ca2+ uptake activities and expression of type II high-capacity Na+-Pi cotransporters. The odontoblast-like phenotype of the cell line was ascertained by monitoring the expression of collagen type I and dentin phosphopoprotein (DPP). Mineralized nodule formation started at day 9 after confluency and then rapidly increased. Ca2+ uptake by the cells showed a maximum during the end of the proliferative phase (days 5-7). Pi uptake declined to a basal level during proliferation and then was up-regulated simultaneously with the onset of mineralization to a level fourfold of the basal uptake, suggesting an initiating and regulatory role for cellular Pi uptake in mineral formation. This up-regulation coincided with a conspicuously increased glycosylation of NaPi-2a, indicating an activation of this Na+-Pi cotransporter. The study showed that MRPC-1 cells express an odontoblast-like phenotype already at the onset of culture, but that to mineralize the collagenous extracellular matrix (ECM) that formed, a further differentiation involving their ion transporters is necessary.
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Affiliation(s)
- P Lundquist
- Department of Oral Biochemistry, Faculty of Odontology, Göteborg University, Sweden
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24
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Allard B, Couble ML, Magloire H, Bleicher F. Characterization and gene expression of high conductance calcium-activated potassium channels displaying mechanosensitivity in human odontoblasts. J Biol Chem 2000; 275:25556-61. [PMID: 10840032 DOI: 10.1074/jbc.m002327200] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Odontoblasts form a layer of cells responsible for the dentin formation and possibly mediate early stages of sensory processing in teeth. Several classes of ion channels have previously been identified in the odontoblast or pulp cell membrane, and it is suspected that these channels assist in these events. This study was carried out to characterize the K(Ca) channels on odontoblasts fully differentiated in vitro using the patch clamp technique and to investigate the HSLO gene expression encoding the alpha-subunit of these channels on odontoblasts in vivo. In inside-out patches, K(Ca) channels were identified on the basis of their K(+) selectivity, conductance, voltage, and Ca(2+) dependence. In cell-attached patches, these channels were found to be activated by application of a negative pressure as well as an osmotic shock. By reverse transcription-polymerase chain reaction, a probe complementary to K(Ca) alpha-subunit mRNA was constructed and used for in situ hybridization on human dental pulp samples. Transcripts were expressed in the odontoblast layer. The use of antibodies showed that the K(Ca) channels were preferentially detected at the apical pole of the odontoblasts. These channels could be involved in mineralization processes. Their mechanosensitivity suggests that the fluid displacement within dentinal tubules could be transduced into electrical cell signals.
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Affiliation(s)
- B Allard
- Laboratoire de Physiologie des Eléments Excitables, UMR CNRS 5578, Université C. Bernard Lyon I, Villeurbanne, France
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25
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Abstract
Recent evidence suggests that extracellular Ca2+ may modulate cell function in mineralized tissue. To determine whether dentinogenic cells, in particular, are sensitive to extracellular Ca2+, fura-2 microfluorometry was used to monitor intracellular calcium levels in odontoblasts freshly isolated from rat incisor. In response to applications of 0.5-4.0 mM extracellular calcium (CaCl2), most odontoblasts (84%; 107/128) showed an increase in intracellular calcium. For the majority of these cells (70%; 75/107), the typical response was biphasic; there was an initial, transient increase in intracellular calcium which reached peak levels within 30-50 s and decayed rapidly, followed by a slower (> 300 s) recovery toward basal levels. In general, the response of these cells to calcium was repeatable and the mean calcium concentration for the half-maximal response was approximately 1.3 mM. This effect could be partially blocked by either 200 microM lanthanum, a nonspecific blocker of Ca2+ channels, or 20 microM dantrolene, a potent inhibitor of Ca2+ release from internal stores. Used in combination, lanthanum, and dantrolene nearly abolished the calcium response completely. In addition, this response was sensitive to the dihydropyridine-sensitive calcium channel blocking agent nicardipine (60 microM), indicating a role for voltage-gated calcium channels during these events. These results show that odontoblasts respond to external calcium through mechanisms involving both influx of external calcium as well as release of calcium from internal stores and suggest a role for extracellular calcium in regulating the function of these cells.
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Affiliation(s)
- L Guo
- Division of Basic Sciences, New York University College of Dentistry, New York, New York 10010-4086, USA
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26
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Zoccola D, Tambutté E, Sénégas-Balas F, Michiels JF, Failla JP, Jaubert J, Allemand D. Cloning of a calcium channel alpha1 subunit from the reef-building coral, Stylophora pistillata. Gene X 1999; 227:157-67. [PMID: 10023047 DOI: 10.1016/s0378-1119(98)00602-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
While the mechanisms of cellular Ca2+ entry associated with cell activation are well characterized, the pathway of continuous uptake of the large amount of Ca2+ needed in the biomineralization process remains largely unknown. Scleractinian corals are one of the major calcifying groups of organisms. Recent studies have suggested that a voltage-dependent Ca2+ channel is involved in the transepithelial transport of Ca2+ used for coral calcification. We report here the cloning and sequencing of a cDNA coding a coral alpha1 subunit Ca2+ channel. This channel is closely related to the L-type family found in vertebrates and invertebrates. Immunohistochemical analysis shows that this channel is present within the calicoblastic ectoderm, the site involved in calcium carbonate precipitation. These data and previous results provide molecular evidence that voltage-dependent Ca2+ channels are involved in calcification. Cnidarians are the most primitive organisms in which a Ca2+ channel has been cloned up to now; evolutionary perspectives on Ca2+ channel diversity are discussed.
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Affiliation(s)
- D Zoccola
- Observatoire Océanologique Européen, Centre Scientifique de Monaco, Avenue Saint Martin, MC-98000, Monaco, Monaco
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27
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Vazquez G, de Boland AR, Boland RL. 1alpha,25-dihydroxy-vitamin-D3-induced store-operated Ca2+ influx in skeletal muscle cells. Modulation by phospholipase c, protein kinase c, and tyrosine kinases. J Biol Chem 1998; 273:33954-60. [PMID: 9852048 DOI: 10.1074/jbc.273.51.33954] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In skeletal muscle cells the steroid hormone 1alpha, 25-dihydroxy-vitamin-D3 (1,25(OH)2D3) nongenomically promotes Ca2+ release from intracellular stores and cation influx through both L-type and store-operated Ca2+ (SOC) channels. In the present work we evaluated the regulation and kinetics of the 1, 25(OH)2D3-stimulated SOC influx in chick muscle cells. Stimulation with 10(-9) M 1,25(OH)2D3 in Ca2+-free medium resulted in a rapid (40-60 s) but transient [Ca2+]i rise, which correlated with sterol-dependent inositol 1,4,5-trisphosphate production. The SOC influx stimulated by the hormone was insensitive to both L-type channel antagonists and polyphosphoinositide-specific phospholipase C (PPI-PLC) inhibitors but was fully inhibitable by La3+ and Ni2+. PPI-PLC blockade prior to 1,25(OH)2D3 stimulation suppressed both the [Ca2+]i transient and the SOC influx. 1,25(OH)2D3-induced SOC entry was markedly increased after 3 min of treatment (30% above basal) and then rapidly reached a steady-state level. The sterol-stimulated SOC influx was prevented by protein kinase C and tyrosine kinase inhibitors but unaffected by blockade of the protein kinase A pathway. None of these inhibitors altered the thapsigargin-induced SOC entry, suggesting the operation of a signaling mechanism different from that for sterol-dependent SOC influx. The present results indicate that 1,25(OH)2D3-induced activation of PPI-PLC is upstream to Ca2+ influx through SOC channels and point for a role of both protein kinase C and tyrosine kinases but not protein kinase A in the regulation of the sterol-dependent SOCE pathway.
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Affiliation(s)
- G Vazquez
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, (8000) Bahía Blanca, Argentina
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28
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Lundgren T, Linde A. Modulation of rat incisor odontoblast plasma membrane-associated Ca2+ with nifedipine. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1373:341-6. [PMID: 9733994 DOI: 10.1016/s0005-2736(98)00124-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In addition to the Ca2+ portion freely dissociated in the cytosol, another Ca2+ pool is associated with plasma membranes and intracellular organelle membranes. This Ca2+ portion is of importance for regulation of, among other things, the cell cycle, actin-mediated processes, and cell morphology. In the literature, dihydropyridines have been reported to influence this membrane-associated pool of Ca2+ under certain conditions. The aim of this investigation was to study possible modulations of plasma membrane-associated Ca2+ upon treatment with nifedipine in vitro in a Ca2+-transporting cell, the dentin-forming odontoblast. The membrane-associated portion of Ca2+ in dissected dentinogenically active rat incisor odontoblasts was monitored by fluorescence spectrophotometry using chlortetracycline as a probe. In addition, images of chlortetracycline-Ca2+ binding were obtained by fluorescence microscopy. It was found that membrane-associated Ca2+ decreased by the dihydropyridine nifedipine, whereas this Ca2+ pool was unaffected by the cellular polarization state, which was in contrast to cytosolic free Ca2+ as measured by fura-2. The results show that the odontoblast plasma membrane-associated Ca2+-pool can be modulated by nifedipine, thus being dependent on the conformational state of the L-type Ca2+ channels.
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Affiliation(s)
- T Lundgren
- Department of Oral Biochemistry, Faculty of Odontology, Göteborg University, P.O. Box 451, S-405 30 Göteborg, Sweden.
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29
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Abstract
It has been suggested that understanding the physiological properties of odontoblasts may be important in understanding the mechanisms underlying both metabolic and transductive processes in dental pulp. Because ion flux(es) may play a critical role in these events, it is of particular interest to understand ionic mechanisms in odontoblast cells. Thus, the aim of this study was to use patch-clamp recording techniques to examine the properties of resident ion channels in freshly dissociated odontoblasts. In recordings made in potassium-rich solutions, cells displayed at least three distinct channel amplitudes, with conductances of 130 +/- 18 pS, 52 +/- 4 pS, and 25 +/- 2 pS, respectively. Channel activity persisted in the presence of potassium salts of impermeant anions, and could be abolished by barium, a non-specific potassium channel blocker. In addition to the potassium conductances, we saw two separate anion channels in the odontoblast membrane. These channels were predominantly chloride-selective, weakly permeable to both acetate and aspartate, and had conductances of 391 +/- 64 pS and 24 +/- 3 pS. While questions remain regarding the functional role of these and other ion channels that presumably reside in the odontoblast membrane, our results demonstrate that it is possible to study ionic mechanisms of the odontoblast at the level of the single cell.
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Affiliation(s)
- L Guo
- Division of Basic Sciences, New York University College of Dentistry, New York 10010-4086, USA
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