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See LP, Sripinun P, Lu W, Li J, Alboloushi N, Alvarez-Periel E, Lee SM, Karabucak B, Wang S, Jordan Sciutto KL, Theken KN, Mitchell CH. Increased Purinergic Signaling in Human Dental Pulps With Inflammatory Pain is Sex-Dependent. THE JOURNAL OF PAIN 2024; 25:1039-1058. [PMID: 37956743 PMCID: PMC11129867 DOI: 10.1016/j.jpain.2023.10.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/22/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023]
Abstract
An enhanced understanding of neurotransmitter systems contributing to pain transmission aids in drug development, while the identification of biological variables like age and sex helps in the development of personalized pain management and effective clinical trial design. This study identified enhanced expression of purinergic signaling components specifically in painful inflammation, with levels increased more in women as compared to men. Inflammatory dental pain is common and potentially debilitating; as inflammation of the dental pulp can occur with or without pain, it provides a powerful model to examine distinct pain pathways in humans. In control tissues, P2X3 and P2X2 receptors colocalized with PGP9.5-positive nerves. Expression of the ecto-nucleotidase NTPDase1 (CD39) increased with exposure to extracellular adenosine triphosphate (ATP), implying CD39 acted as a marker for sustained elevation of extracellular ATP. Both immunohistochemistry and immunoblots showed P2X2, P2X3, and CD39 increased in symptomatic pulpitis, suggesting receptors and the ATP agonist were elevated in patients with increased pain. The increased expression of P2X3 and CD39 was more frequently observed in women than men. In summary, this study identifies CD39 as a marker for chronic elevation of extracellular ATP in fixed human tissue. It supports a role for increased purinergic signaling in humans with inflammatory dental pain and suggests the contribution of purines shows sexual dimorphism. This highlights the potential for P2X antagonists to treat pain in humans and stresses the need to consider sex in clinical trials that target pain and purinergic pathways. PERSPECTIVE: This article demonstrates an elevation of ATP-marker CD39 and of ATP receptors P2X2 and P2X3 with inflammatory pain and suggests the rise is greater in women. This highlights the potential for P2X antagonists to treat pain and stresses the consideration of sexual dimorphism in studies of purines and pain.
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Affiliation(s)
- Lily P. See
- Departments of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104
- Department of Endodontics, University of Pennsylvania, Philadelphia, PA 19104
| | - Puttipong Sripinun
- Departments of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104
- Department of Orthodontics, University of Pennsylvania, Philadelphia, PA 19104
| | - Wennan Lu
- Departments of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104
| | - Jiaqi Li
- Departments of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104
| | - Naela Alboloushi
- Department of Endodontics, University of Pennsylvania, Philadelphia, PA 19104
- Department of Oral Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Su-Min Lee
- Department of Endodontics, University of Pennsylvania, Philadelphia, PA 19104
| | - Bekir Karabucak
- Department of Endodontics, University of Pennsylvania, Philadelphia, PA 19104
| | - Steven Wang
- Department of Oral Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Katherine N. Theken
- Department of Oral Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | - Claire H. Mitchell
- Departments of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104
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2
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McAllister BB, Stokes-Heck S, Harding EK, van den Hoogen NJ, Trang T. Targeting Pannexin-1 Channels: Addressing the 'Gap' in Chronic Pain. CNS Drugs 2024; 38:77-91. [PMID: 38353876 DOI: 10.1007/s40263-024-01061-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/07/2024] [Indexed: 02/22/2024]
Abstract
Chronic pain complicates many diseases and is notoriously difficult to treat. In search of new therapeutic targets, pannexin-1 (Panx1) channels have sparked intense interest as a key mechanism involved in a variety of chronic pain conditions. Panx1 channels are transmembrane proteins that release ions and small molecules, such as adenosine triphosphate (ATP). They are expressed along important nodes of the pain pathway, modulating activity of diverse cell types implicated in the development and progression of chronic pain caused by injury or pathology. This review highlights advances that have unlocked the core structure and machinery controlling Panx1 function with a focus on understanding and treating chronic pain.
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Affiliation(s)
- Brendan B McAllister
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada
| | - Sierra Stokes-Heck
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada
| | - Erika K Harding
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada
| | - Nynke J van den Hoogen
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada
| | - Tuan Trang
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, AB, T2N 4N1, Canada.
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3
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Wang Q, Luan J, Zhao Z, Kong W, Zhang C, Ding J. Dentin-desensitizing biomaterials. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.108060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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4
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Sun XF, Qiao WW, Meng LY, Bian Z. PIEZO1 Ion Channels Mediate Mechanotransduction in Odontoblasts. J Endod 2022; 48:749-758. [DOI: 10.1016/j.joen.2022.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 01/30/2022] [Accepted: 02/07/2022] [Indexed: 12/21/2022]
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Immunohistochemistry as a detection tool for ion channels involved in dental pain signaling. Saudi Dent J 2022; 34:155-166. [PMID: 35935722 PMCID: PMC9346947 DOI: 10.1016/j.sdentj.2022.02.004] [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: 08/01/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
Background Despite advances in pain detection, diagnosis, and management, the prevalence of dental pain is still on the rise. Although dental pain is not directly related to fatal outcomes, the two most common types of dental pain—dental caries and dentin hypersensitivity—have a significant impact on an individual’s quality of life. Understanding the mechanism of the pain pathway is one of the crucial steps in providing better treatment for these patients. Ion channels are critical biomolecules that have been the subject of dental study owing to their roles in the transmission and transduction of external stimuli, as well as in the control and perception of pain. Numerous immunohistochemical (IHC) staining approaches have also been used to identify the many ion channels implicated in peripheral pain signaling in dental pulp. Highlight This review highlights the critical steps in IHC and its role in the detection of ion channels involved in the dental pain signaling pathway. Conclusion The key ion channels identified using IHC and whose functions have been widely researched in dental tissues are addressed in this review article.
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6
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Calabrese EJ, Agathokleous E, Dhawan G, Kapoor R, Calabrese V. Human dental pulp stem cells and hormesis. Ageing Res Rev 2022; 73:101540. [PMID: 34890824 DOI: 10.1016/j.arr.2021.101540] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/26/2021] [Accepted: 12/05/2021] [Indexed: 02/06/2023]
Abstract
This paper represents the first assessment of hormetic dose responses by human dental pulp stem cells (hDPSCs) with particular emphasis on cell renewal (proliferation) and differentiation. Hormetic dose responses were commonly reported in this model, encompassing a broad range of chemicals, including principally pharmaceuticals (e.g., metformin and artemisinin), dietary supplements/extracts from medicinal plants (e.g., berberine, N-acetyl-L-cysteine, and ginsenoside Rg1) and endogenous agents (e.g., ATP, TNF-α). The paper assesses mechanistic foundations of the hDPSCs hormetic dose responses for both cell proliferation and cell differentiation, study design considerations, and therapeutic implications.
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Yan H, Oshima M, Raju R, Raman S, Sekine K, Waskitho A, Inoue M, Inoue M, Baba O, Morita T, Miyagi M, Matsuka Y. Dentin-Pulp Complex Tissue Regeneration via Three-Dimensional Cell Sheet Layering. Tissue Eng Part C Methods 2021; 27:559-570. [PMID: 34583551 DOI: 10.1089/ten.tec.2021.0171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The dentin-pulp complex is a unique structure in teeth that contains both hard and soft tissues. Generally, deep caries and trauma cause damage to the dentin-pulp complex, and if left untreated, this damage will progress to irreversible pulpitis. The aim of this study was to fabricate a layered cell sheet composed of rat dental pulp (DP) cells and odontogenic differentiation of pulp (OD) cells and to investigate the ability to regenerate the dentin-pulp complex in a scaffold tooth. We fabricated two single cell sheets composed of DP cells (DP cell sheet) or OD cells (OD cell sheet) and a layered cell sheet made by layering both cells. The characteristics of the fabricated cell sheets were analyzed using light microscopy, scanning electron microscope (SEM), hematoxylin-eosin (HE) staining, and immunohistochemistry (IHC). Furthermore, the cell sheets were transplanted into the subrenal capsule of immunocompromised mice for 8 weeks. After this, the regenerative capacity to form dentin-like tissue was evaluated using micro-computed tomography (micro-CT), HE staining, and IHC. The findings of SEM and IHC confirmed that layered cell sheets fabricated by stacking OD cells and DP cells maintained their cytological characteristics. Micro-CT of layered cell sheet transplants revealed a mineralized capping of the access cavity in the crown area, similar to that of natural dentin. In contrast, the OD cell sheet group demonstrated the formation of irregular fragments of mineralized tissue in the pulp cavity, and the DP cell sheet did not develop any hard tissue. Moreover, bone volume/tissue volume (BV/TV) showed a significant increase in hard tissue formation in the layered cell sheet group compared with that in the single cell sheet group (p < 0.05). HE staining also showed a combination of soft and hard tissue formation in the layered cell sheet group. Furthermore, IHC confirmed that the dentin-like tissue generated from the layered cell sheet expressed characteristic markers of dentin but not bone equivalent to that of a natural tooth. In conclusion, this study demonstrates the feasibility of regenerating dentin-pulp complex using a bioengineered tissue designed to simulate the anatomical structure. Impact statement The dentin-pulp complex can be destroyed by deep caries and trauma, which may cause pulpitis and progress to irreversible pulpitis, apical periodontitis, and even tooth loss. Current treatments cannot maintain pulp health, and teeth can become brittle. We developed a three-dimensional (3D) layered cell sheet using dental pulp cells and odontogenic differentiation of pulp cells for dentin-pulp complex regeneration. Our layered cell sheet enables the regeneration of an organized 3D dentin-pulp-like structure comparable with that of natural teeth. This layered cell sheet technology may contribute to dentin-pulp complex regeneration and provide a novel method for complex tissue engineering.
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Affiliation(s)
- Huijiao Yan
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Masamitsu Oshima
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Resmi Raju
- Department of Oral Disease Research, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Swarnalakshmi Raman
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Kazumitsu Sekine
- Department of Biomaterials and Bioengineering, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Arief Waskitho
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Miho Inoue
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Masahisa Inoue
- Laboratories for Structure and Function Research, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
| | - Otto Baba
- Department of Oral and Maxillofacial Anatomy, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Tsuyoshi Morita
- Department of Oral and Maxillofacial Anatomy, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Mayu Miyagi
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Yoshizo Matsuka
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
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8
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Liu XX, Tenenbaum HC, Wilder RS, Quock R, Hewlett ER, Ren YF. Pathogenesis, diagnosis and management of dentin hypersensitivity: an evidence-based overview for dental practitioners. BMC Oral Health 2020; 20:220. [PMID: 32762733 PMCID: PMC7409672 DOI: 10.1186/s12903-020-01199-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 07/20/2020] [Indexed: 01/01/2023] Open
Abstract
Though dentin hypersensitivity (DHS) is one of the most common complaints from patients in dental clinics, there are no universally accepted guidelines for differential diagnosis as well as selection of reliable treatment modalities for this condition. The neurosensory mechanisms underlying DHS remain unclear, but fluid movements within exposed dentinal tubules, i.e., the hydrodynamic theory, has been a widely accepted explanation for DHS pain. As several dental conditions have symptoms that mimic DHS at different stages of their progression, diagnosis and treatment of DHS are often confusing, especially for inexperienced dental practitioners. In this paper we provide an up-to-date review on risk factors that play a role in the development and chronicity of DHS and summarize the current principles and strategies for differential diagnosis and management of DHS in dental practices. We will outline the etiology, predisposing factors and the underlying putative mechanisms of DHS, and provide principles and indications for its diagnosis and management. Though desensitization remains to be the first choice for DHS for many dental practitioners and most of desensitizing agents reduce the symptoms of DHS by occluding patent dentinal tubules, the long-term outcome of such treatment is uncertain. With improved understanding of the underlying nociceptive mechanisms of DHS, it is expected that promising novel therapies will emerge and provide more effective relief for patients with DHS.
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Affiliation(s)
- Xiu-Xin Liu
- Department of General Dentistry, Eastman Institute for Oral Health, University of Rochester, 625 Elmwood Ave, Rochester, NY, 14620, USA.,Department of Dentistry, Atlanta VA Medical Center, Atlanta, GA, USA
| | - Howard C Tenenbaum
- Department of Periodontology, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Rebecca S Wilder
- Office for Professional Development and Faculty Affairs, Adams School of Dentistry, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ryan Quock
- Department of Restorative Dentistry & Prosthodontics, University of Texas School of Dentistry at Houston, Houston, TX, USA
| | - Edmond R Hewlett
- Section of Restorative Dentistry, UCLA School of Dentistry, Los Angeles, California, USA
| | - Yan-Fang Ren
- Department of General Dentistry, Eastman Institute for Oral Health, University of Rochester, 625 Elmwood Ave, Rochester, NY, 14620, USA. .,Outreach and Diversity, UCLA School of Dentistry, Los Angeles, California, USA.
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9
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Pannexin-1 Channel Regulates ATP Release in Epilepsy. Neurochem Res 2020; 45:965-971. [PMID: 32170674 DOI: 10.1007/s11064-020-02981-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 01/16/2020] [Accepted: 02/01/2020] [Indexed: 12/28/2022]
Abstract
With the deepening of research on epilepsy in recent decades, great progress has been made in the diagnosis and treatment of the disease. However, the clinical outcome remains unsatisfactory due to the confounding symptoms and complications, as well as complex intrinsic pathogenesis. A better understanding of the pathogenesis of epilepsy should be able to hinder the progress of the disease and improve the therapeutic effectiveness. Since the discovery of pannexin (Panx), unremitting efforts on the study of this gap junction protein family member have revealed its role in participating in the expression of various physiopathological processes. Among them, the activation or inhibition of Panx channel has been shown to regulate the release of adenosine triphosphate (ATP) and other signals, which is very important for the onset and control of nervous system diseases including epilepsy. In this article, we summarize the factors influencing the regulation of Panx channel opening, hoping to find a way to interfere with the activation or inhibition of Panx channel that regulates the signal transduction of ATP and other factors so as to control the progression of epilepsy and improve the quality of life of epileptic patients who fail to respond to the existing medical therapies and those at risk of surgical treatment.
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10
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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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11
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Hossain MZ, Bakri MM, Yahya F, Ando H, Unno S, Kitagawa J. The Role of Transient Receptor Potential (TRP) Channels in the Transduction of Dental Pain. Int J Mol Sci 2019; 20:ijms20030526. [PMID: 30691193 PMCID: PMC6387147 DOI: 10.3390/ijms20030526] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 12/18/2022] Open
Abstract
Dental pain is a common health problem that negatively impacts the activities of daily living. Dentine hypersensitivity and pulpitis-associated pain are among the most common types of dental pain. Patients with these conditions feel pain upon exposure of the affected tooth to various external stimuli. However, the molecular mechanisms underlying dental pain, especially the transduction of external stimuli to electrical signals in the nerve, remain unclear. Numerous ion channels and receptors localized in the dental primary afferent neurons (DPAs) and odontoblasts have been implicated in the transduction of dental pain, and functional expression of various polymodal transient receptor potential (TRP) channels has been detected in DPAs and odontoblasts. External stimuli-induced dentinal tubular fluid movement can activate TRP channels on DPAs and odontoblasts. The odontoblasts can in turn activate the DPAs by paracrine signaling through ATP and glutamate release. In pulpitis, inflammatory mediators may sensitize the DPAs. They could also induce post-translational modifications of TRP channels, increase trafficking of these channels to nerve terminals, and increase the sensitivity of these channels to stimuli. Additionally, in caries-induced pulpitis, bacterial products can directly activate TRP channels on DPAs. In this review, we provide an overview of the TRP channels expressed in the various tooth structures, and we discuss their involvement in the development of dental pain.
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Affiliation(s)
- Mohammad Zakir Hossain
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
| | - Marina Mohd Bakri
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Farhana Yahya
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Hiroshi Ando
- Department of Biology, School of Dentistry, Matsumoto Dental University, 1780 Gobara, Hirooka, Shiojiri, Nagano 399-0781, Japan.
| | - Shumpei Unno
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
| | - Junichi Kitagawa
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
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12
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Zhang S, Ye D, Ma L, Ren Y, Dirksen RT, Liu X. Purinergic Signaling Modulates Survival/Proliferation of Human Dental Pulp Stem Cells. J Dent Res 2018; 98:242-249. [PMID: 30383477 DOI: 10.1177/0022034518807920] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Human dental pulp stem cells (hDPSCs) reside in postnatal dental pulp and exhibit the potential to differentiate into odontoblasts as well as neurons. However, the intercellular signaling niches necessary for hDPSC survival and self-renewal remain largely unknown. The objective of this study is to demonstrate the existence of intercellular purinergic signaling in hDPSCs and to assess the impact of purinergic signaling on hDPSC survival and proliferation. hDPSCs were isolated from extracted third molars and cultured in minimum essential medium. To demonstrate responsiveness to ATP application and inhibitions by purinergic receptor antagonists, whole cell patch-clamp recordings of ATP-induced currents were recorded from cultured hDPSCs. Immunofluorescence and enzymatic histochemistry staining were performed to assess purinergic receptor expression and ectonucleotidase activity in hDPSCs, respectively. To determine the effects of purinergic signaling on hDPSC, purinergic receptor antagonists and an ectonucleotidase inhibitor were applied in culture medium, and hDPSC survival and proliferation were assessed with DAPI staining and Ki67 immunofluorescence staining, respectively. We demonstrated that ATP application induced inward currents in hDPSCs. P2X and P2Y receptors are involved in the generation of ATP-induced inward currents. We also detected expression of NTPDase3 and ectonucleotidase activity in hDPSCs. We further demonstrated that purinergic receptors were tonically activated in hDPSCs and that inhibition of ectonucleotidase activity enhanced ATP-induced inward currents. Furthermore, we found that blocking P2Y and P2X receptors reduced-and inhibition of ecto-ATPase activity enhanced-the survival and proliferation of hDPSCs, while blocking P2X receptors alone affected only hDPSC proliferation. Autocrine/paracrine purinergic signaling is essential for hDPSC survival and proliferation. These results reveal potential targets to manipulate hDPSCs to promote tooth/dental pulp repair and regeneration.
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Affiliation(s)
- S Zhang
- 1 Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - D Ye
- 1 Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - L Ma
- 2 Department of Dentistry, School of Stomatology, Zhengzhou University, Zhengzhou, China, China
| | - Y Ren
- 1 Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - R T Dirksen
- 3 Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - X Liu
- 1 Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.,3 Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.,4 Department of Dentistry, Atlanta VA Medical Center, Decatur, GA, USA
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13
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Sato M, Ogura K, Kimura M, Nishi K, Ando M, Tazaki M, Shibukawa Y. Activation of Mechanosensitive Transient Receptor Potential/Piezo Channels in Odontoblasts Generates Action Potentials in Cocultured Isolectin B 4-negative Medium-sized Trigeminal Ganglion Neurons. J Endod 2018; 44:984-991.e2. [PMID: 29709295 DOI: 10.1016/j.joen.2018.02.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 02/15/2018] [Accepted: 02/20/2018] [Indexed: 01/22/2023]
Abstract
INTRODUCTION Various stimuli to the dentin surface elicit dentinal pain by inducing dentinal fluid movement causing cellular deformation in odontoblasts. Although odontoblasts detect deformation by the activation of mechanosensitive ionic channels, it is still unclear whether odontoblasts are capable of establishing neurotransmission with myelinated A delta (Aδ) neurons. Additionally, it is still unclear whether these neurons evoke action potentials by neurotransmitters from odontoblasts to mediate sensory transduction in dentin. Thus, we investigated evoked inward currents and evoked action potentials form trigeminal ganglion (TG) neurons after odontoblast mechanical stimulation. METHODS We used patch clamp recordings to identify electrophysiological properties and record evoked responses in TG neurons. RESULTS We classified TG cells into small-sized and medium-sized neurons. In both types of neurons, we observed voltage-dependent inward currents. The currents from medium-sized neurons showed fast inactivation kinetics. When mechanical stimuli were applied to odontoblasts, evoked inward currents were recorded from medium-sized neurons. Antagonists for the ionotropic adenosine triphosphate receptor (P2X3), transient receptor potential channel subfamilies, and Piezo1 channel significantly inhibited these inward currents. Mechanical stimulation to odontoblasts also generated action potentials in the isolectin B4-negative medium-sized neurons. Action potentials in these isolectin B4-negative medium-sized neurons showed a short duration. Overall, electrophysiological properties of neurons indicate that the TG neurons with recorded evoked responses after odontoblast mechanical stimulation were myelinated Aδ neurons. CONCLUSIONS Odontoblasts established neurotransmission with myelinated Aδ neurons via P2X3 receptor activation. The results also indicated that mechanosensitive TRP/Piezo1 channels were functionally expressed in odontoblasts. The activation of P2X3 receptors induced an action potential in the Aδ neurons, underlying a sensory generation mechanism of dentinal pain.
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Affiliation(s)
- Masaki Sato
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
| | - Kazuhiro Ogura
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
| | - Maki Kimura
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
| | - Koichi Nishi
- Removable Prosthodontics and Gerodontology, Tokyo Dental College, Tokyo, Japan
| | - Masayuki Ando
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
| | - Masakazu Tazaki
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
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14
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Yi X, Wang W, Xie Q. Adenosine receptors enhance the ATP-induced odontoblastic differentiation of human dental pulp cells. Biochem Biophys Res Commun 2018; 497:850-856. [PMID: 29454963 DOI: 10.1016/j.bbrc.2018.02.125] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 02/14/2018] [Indexed: 01/12/2023]
Abstract
Purinergic signaling regulates various biological processes through the activation of adenosine receptors (ARs) and P2 receptors. ATP induces the odontoblastic differentiation of human dental pulp cells (HDPCs) via P2 receptors. However, there is no information available about the roles of ARs in HDPC odontoblastic differentiation induced by ATP. Here, we found that HDPCs treated with ATP showed higher activity of ADORA1 (A1R), ADORA2B (A2BR), and ADORA3 (A3R). Inhibition of A1R and A2BR attenuated ATP-induced odontoblastic differentiation of HDPCs, whereas activation of the two receptors enhanced the odontoblastic differentiation induced by ATP. However, activation of ARs by adenosine did not induce the odontoblastic differentiation of HDPCs independently without induction of ATP. Our study indicates a positive role for ARs in ATP-induced odontoblastic differentiation of HDPCs, and demonstrates that ATP-induced odontoblastic differentiation of HDPCs may be due to the combined administration of ARs and P2 receptors. This study provides new insights into the molecular mechanisms of pulpal injury repair induced by ATP.
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Affiliation(s)
- Xiaosong Yi
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China; Center for Oral Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology, China
| | - Wei Wang
- Department of Stomatology, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, Shenzhen, Guangdong, China
| | - Qiufei Xie
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China; Center for Oral Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology, China.
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15
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Burnstock G. Purinergic Signalling: Therapeutic Developments. Front Pharmacol 2017; 8:661. [PMID: 28993732 PMCID: PMC5622197 DOI: 10.3389/fphar.2017.00661] [Citation(s) in RCA: 275] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/05/2017] [Indexed: 12/15/2022] Open
Abstract
Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990's when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine) receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and biochemistry of purinergic signalling. More recently, the focus has been on the pathophysiology and therapeutic potential. There was early recognition of the use of P1 receptor agonists for the treatment of supraventricular tachycardia and A2A receptor antagonists are promising for the treatment of Parkinson's disease. Clopidogrel, a P2Y12 antagonist, is widely used for the treatment of thrombosis and stroke, blocking P2Y12 receptor-mediated platelet aggregation. Diquafosol, a long acting P2Y2 receptor agonist, is being used for the treatment of dry eye. P2X3 receptor antagonists have been developed that are orally bioavailable and stable in vivo and are currently in clinical trials for the treatment of chronic cough, bladder incontinence, visceral pain and hypertension. Antagonists to P2X7 receptors are being investigated for the treatment of inflammatory disorders, including neurodegenerative diseases. Other investigations are in progress for the use of purinergic agents for the treatment of osteoporosis, myocardial infarction, irritable bowel syndrome, epilepsy, atherosclerosis, depression, autism, diabetes, and cancer.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical SchoolLondon, United Kingdom
- Department of Pharmacology and Therapeutics, The University of Melbourne, MelbourneVIC, Australia
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16
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Solé-Magdalena A, Martínez-Alonso M, Coronado CA, Junquera LM, Cobo J, Vega JA. Molecular basis of dental sensitivity: The odontoblasts are multisensory cells and express multifunctional ion channels. Ann Anat 2017; 215:20-29. [PMID: 28954208 DOI: 10.1016/j.aanat.2017.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/22/2017] [Accepted: 09/10/2017] [Indexed: 12/26/2022]
Abstract
Odontoblasts are the dental pulp cells responsible for the formation of dentin. In addition, accumulating data strongly suggest that they can also function as sensory cells that mediate the early steps of mechanical, thermic, and chemical dental sensitivity. This assumption is based on the expression of different families of ion channels involved in various modalities of sensitivity and the release of putative neurotransmitters in response to odontoblast stimulation which are able to act on pulp sensory nerve fibers. This review updates the current knowledge on the expression of transient-potential receptor ion channels and acid-sensing ion channels in odontoblasts, nerve fibers innervating them and trigeminal sensory neurons, as well as in pulp cells. Moreover, the innervation of the odontoblasts and the interrelationship been odontoblasts and nerve fibers mediated by neurotransmitters was also revisited. These data might provide the basis for novel therapeutic approaches for the treatment of dentin sensibility and/or dental pain.
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Affiliation(s)
- A Solé-Magdalena
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - M Martínez-Alonso
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - C A Coronado
- Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile
| | - L M Junquera
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Servicio de Cirugía Maxilofacial, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - J Cobo
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Instituto Asturiano de Odontología, Oviedo, Spain
| | - J A Vega
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain; Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile.
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17
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Tazawa K, Ikeda H, Kawashima N, Okiji T. Transient receptor potential melastatin (TRPM) 8 is expressed in freshly isolated native human odontoblasts. Arch Oral Biol 2017; 75:55-61. [DOI: 10.1016/j.archoralbio.2016.12.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 01/20/2023]
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18
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Liu X, Ma L, Zhang S, Ren Y, Dirksen RT. CD73 Controls Extracellular Adenosine Generation in the Trigeminal Nociceptive Nerves. J Dent Res 2017; 96:671-677. [PMID: 28530470 DOI: 10.1177/0022034517692953] [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] [Indexed: 12/30/2022] Open
Abstract
Purinergic signaling is involved in pain generation and modulation in the nociceptive sensory nervous system. Adenosine triphosphate (ATP) induces pain via activation of ionotropic P2X receptors while adenosine mediates analgesia via activation of metabotropic P1 receptors. These purinergic signaling are determined by ecto-nucleotidases that control ATP degradation and adenosine generation. Using enzymatic histochemistry, we detected ecto-AMPase activity in dental pulp, trigeminal ganglia (TG) neurons, and their nerve fibers. Using immunofluorescence staining, we confirmed the expression of ecto-5'-nucleotidase (CD73) in trigeminal nociceptive neurons and their axonal fibers, including the nociceptive nerve fibers projecting into the brainstem. In addition, we detected the existence of CD73 and ecto-AMPase activity in the nociceptive lamina of the trigeminal subnucleus caudalis (TSNC) in the brainstem. Furthermore, we demonstrated that incubation with specific anti-CD73 serum significantly reduced the ecto-AMPase activity in the nociceptive lamina in the brainstem. Our results indicate that CD73 might participate in nociceptive modulation by affecting extracellular adenosine generation in the trigeminal nociceptive pathway. Disruption of TG neuronal ecto-nucleotidase expression and axonal terminal localization under certain circumstances such as chronic inflammation, oxidant stress, local constriction, and injury in trigeminal nerves may contribute to the pathogenesis of orofacial neuropathic pain.
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Affiliation(s)
- X Liu
- 1 Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.,2 Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - L Ma
- 1 Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.,3 Department of Dentistry, School of Stomatology, Zhengzhou University, Zhengzhou, China
| | - S Zhang
- 1 Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Y Ren
- 1 Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - R T Dirksen
- 2 Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
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19
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Shiozaki Y, Sato M, Kimura M, Sato T, Tazaki M, Shibukawa Y. Ionotropic P2X ATP Receptor Channels Mediate Purinergic Signaling in Mouse Odontoblasts. Front Physiol 2017; 8:3. [PMID: 28163685 PMCID: PMC5247440 DOI: 10.3389/fphys.2017.00003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/04/2017] [Indexed: 11/29/2022] Open
Abstract
ATP modulates various functions in the dental pulp cells, such as intercellular communication and neurotransmission between odontoblasts and neurons, proliferation of dental pulp cells, and odontoblast differentiation. However, functional expression patterns and their biophysical properties of ionotropic ATP (P2X) receptors (P2X1–P2X7) in odontoblasts were still unclear. We examined these properties of P2X receptors in mouse odontoblasts by patch-clamp recordings. K+-ATP, nonselective P2X receptor agonist, induced inward currents in odontoblasts in a concentration-dependent manner. K+-ATP-induced currents were inhibited by P2X4 and P2X7 selective inhibitors (5-BDBD and KN62, respectively), while P2X1 and P2X3 inhibitors had no effects. P2X7 selective agonist (BzATP) induced inward currents dose-dependently. We could not observe P2X1, 2/3, 3 selective agonist (αβ-MeATP) induced currents. Amplitudes of K+-ATP-induced current were increased in solution without extracellular Ca2+, but decreased in Na+-free extracellular solution. In the absence of both of extracellular Na+ and Ca2+, K+-ATP-induced currents were completely abolished. K+-ATP-induced Na+ currents were inhibited by P2X7 inhibitor, while the Ca2+ currents were sensitive to P2X4 inhibitor. These results indicated that odontoblasts functionally expressed P2X4 and P2X7 receptors, which might play an important role in detecting extracellular ATP following local dental pulp injury.
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Affiliation(s)
- Yuta Shiozaki
- Department of Physiology, Tokyo Dental CollegeTokyo, Japan; Department of Crown and Bridge Prosthodontics, Tokyo Dental CollegeTokyo, Japan
| | - Masaki Sato
- Department of Physiology, Tokyo Dental College Tokyo, Japan
| | - Maki Kimura
- Department of Physiology, Tokyo Dental College Tokyo, Japan
| | - Toru Sato
- Department of Crown and Bridge Prosthodontics, Tokyo Dental College Tokyo, Japan
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20
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Ma L, Trinh T, Ren Y, Dirksen RT, Liu X. Neuronal NTPDase3 Mediates Extracellular ATP Degradation in Trigeminal Nociceptive Pathway. PLoS One 2016; 11:e0164028. [PMID: 27706204 PMCID: PMC5051867 DOI: 10.1371/journal.pone.0164028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/19/2016] [Indexed: 01/05/2023] Open
Abstract
ATP induces pain via activation of purinergic receptors in nociceptive sensory nerves. ATP signaling is terminated by ATP hydrolysis mediated by cell surface-localized ecto-nucleotidases. Using enzymatic histochemical staining, we show that ecto-ATPase activity is present in mouse trigeminal nerves. Using immunofluorescence staining, we found that ecto-NTPDase3 is expressed in trigeminal nociceptive neurons and their projections to the brainstem. In addition, ecto-ATPase activity and ecto-NTPDase3 are also detected in the nociceptive outermost layer of the trigeminal subnucleus caudalis. Furthermore, we demonstrate that incubation with anti-NTPDase3 serum reduces extracellular ATP degradation in the nociceptive lamina of both the trigeminal subnucleus caudalis and the spinal cord dorsal horn. These results are consistent with neuronal NTPDase3 activity modulating pain signal transduction and transmission by affecting extracellular ATP hydrolysis within the trigeminal nociceptive pathway. Thus, disruption of trigeminal neuronal NTPDase3 expression and localization to presynaptic terminals during chronic inflammation, local constriction and injury may contribute to the pathogenesis of orofacial neuropathic pain.
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Affiliation(s)
- Lihua Ma
- Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
- Department of Dentistry, School of Stomatology, Zhengzhou University, Zhengzhou, China
| | - Thu Trinh
- Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
| | - Yanfang Ren
- Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
| | - Robert T. Dirksen
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
| | - Xiuxin Liu
- Department of Dentistry, Eastman Institute for Oral Health, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
- * E-mail:
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21
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Lee BM, Jo H, Park G, Kim YH, Park CK, Jung SJ, Chung G, Oh SB. Extracellular ATP Induces Calcium Signaling in Odontoblasts. J Dent Res 2016; 96:200-207. [PMID: 27694154 DOI: 10.1177/0022034516671308] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Odontoblasts form dentin at the outermost surface of tooth pulp. An increasing level of evidence in recent years, along with their locational advantage, implicates odontoblasts as a secondary role as sensory or immune cells. Extracellular adenosine triphosphate (ATP) is a well-characterized signaling molecule in the neuronal and immune systems, and its potential involvement in interodontoblast communications was recently demonstrated. In an effort to elaborate the ATP-mediated signaling pathway in odontoblasts, the current study performed single-cell reverse transcription polymerase chain reaction (RT-PCR) and immunofluorescent detection to investigate the expression of ATP receptors related to calcium signal in odontoblasts from incisal teeth of 8- to 10-wk-old rats, and demonstrated an in vitro response to ATP application via calcium imaging experiments. While whole tissue RT-PCR analysis detected P2Y2, P2Y4, and all 7 subtypes (P2X1 to P2X7) in tooth pulp, single-cell RT-PCR analysis of acutely isolated rat odontoblasts revealed P2Y2, P2Y4, P2X2, P2X4, P2X6, and P2X7 expression in only a subset (23% to 47%) of cells tested, with no evidence for P2X1, P2X3, and P2X5 expression. An increase of intracellular Ca2+ concentration in response to 100μM ATP, which was repeated after pretreatment of thapsigargin or under the Ca2+-free condition, suggested function of both ionotropic and metabotropic ATP receptors in odontoblasts. The enhancement of ATP-induced calcium response by ivermectin and inhibition by 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one (5-BDBD) confirmed a functional P2X4 subtype in odontoblasts. Positive calcium response to 2',3'-O-(benzoyl-4-benzoyl)-ATP (BzATP) and negative response to α,β-methylene ATP suggested P2X2, P2X4, and P2X7 as functional subunits in rat odontoblasts. Single-cell RT-PCR analysis of the cells with confirmed calcium response and immunofluorescent detection further corroborated the expression of P2X4 and P2X7 in odontoblasts. Overall, this study demonstrated heterogeneous expression of calcium-related ATP receptor subtypes in subsets of individual odontoblasts, suggesting extracellular ATP as a potential signal mediator for odontoblastic functions.
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Affiliation(s)
- B M Lee
- 1 Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - H Jo
- 1 Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - G Park
- 1 Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Y H Kim
- 1 Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - C K Park
- 2 Department of Physiology, Graduate School of Medicine, Gachon University, Incheon, Republic of Korea
| | - S J Jung
- 3 Department of Physiology, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - G Chung
- 1 Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - S B Oh
- 1 Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
- 4 Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
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22
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Wang W, Yi X, Ren Y, Xie Q. Effects of Adenosine Triphosphate on Proliferation and Odontoblastic Differentiation of Human Dental Pulp Cells. J Endod 2016; 42:1483-9. [PMID: 27576209 DOI: 10.1016/j.joen.2016.07.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 06/11/2016] [Accepted: 07/17/2016] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Adenosine 5'-triphosphate (ATP) is a potent signaling molecule that regulates diverse biological activities in cells. Its effects on human dental pulp cells (HDPCs) remain unknown. This study aimed to examine the effects of ATP on proliferation and differentiation of HDPCs. METHODS Reverse transcription polymerase chain reaction was performed to explore the mRNA expression of P2 receptor subtypes. Cell Counting Kit-8 test and flow cytometry analysis were used to examine the effects of ATP on proliferation and cell cycle of HDPCs. The effects of ATP on differentiation of HDPCs were examined by using alizarin red S staining, energy-dispersive x-ray analysis, Western blot analysis, and real-time polymerase chain reaction. RESULTS The purinoceptors P2X3, P2X4, P2X5, P2X7, and all P2Y receptor subtypes were confirmed to present in HDPCs. ATP enhanced HDPC proliferation at 10 μmol/L concentration. However, it inhibited cell proliferation by arresting the cell cycle in G0G1 phase (P < .05 versus control) and induced odontoblastic differentiation, ERK/MAPK activation, and dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP) mRNA transcriptions at 800 μmol/L concentration. Suramin, an ATP receptor antagonist, inhibited ERK/MAPK activation and HDPC odontoblastic differentiation (P < .05 versus control). CONCLUSIONS Extracellular ATP activates P2 receptors and downstream signaling events that induce HDPC odontogenic differentiation. Thus, ATP may promote dental pulp tissue healing and repair through P2 signaling. Results provide new insights into the molecular regulation of pulpal wound healing.
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Affiliation(s)
- Wei Wang
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China; Center for Oral Functional Diagnosis, Treatment, and Research, Peking University School and Hospital of Stomatology, Beijing, China; Department of Stomatology, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, Shenzhen, Guangdong, China
| | - Xiaosong Yi
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China; Center for Oral Functional Diagnosis, Treatment, and Research, Peking University School and Hospital of Stomatology, Beijing, China
| | - Yanfang Ren
- University of Rochester Eastman Institute for Oral Health, Rochester, New York
| | - Qiufei Xie
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China; Center for Oral Functional Diagnosis, Treatment, and Research, Peking University School and Hospital of Stomatology, Beijing, China.
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Proteomic analysis of human tooth pulp proteomes – Comparison of caries-resistant and caries-susceptible persons. J Proteomics 2016; 145:127-136. [DOI: 10.1016/j.jprot.2016.04.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/08/2016] [Accepted: 04/17/2016] [Indexed: 01/13/2023]
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24
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Nishiyama A, Sato M, Kimura M, Katakura A, Tazaki M, Shibukawa Y. Intercellular signal communication among odontoblasts and trigeminal ganglion neurons via glutamate. Cell Calcium 2016; 60:341-355. [PMID: 27452727 DOI: 10.1016/j.ceca.2016.07.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 01/01/2023]
Abstract
Various stimuli to the exposed surface of dentin induce changes in the hydrodynamic force inside the dentinal tubules resulting in dentinal pain. Recent evidences indicate that mechano-sensor channels, such as the transient receptor potential channels, in odontoblasts receive these hydrodynamic forces and trigger the release of ATP to the pulpal neurons, to generate dentinal pain. A recent study, however, has shown that odontoblasts also express glutamate receptors (GluRs). This implies that cells in the dental pulp tissue have the ability to release glutamate, which acts as a functional intercellular mediator to establish inter-odontoblast and odontoblast-trigeminal ganglion (TG) neuron signal communication. To investigate the intercellular signal communication, we applied mechanical stimulation to odontoblasts and measured the intracellular free Ca2+ concentration ([Ca2+]i). During mechanical stimulation in the presence of extracellular Ca2+, we observed a transient [Ca2+]i increase not only in single stimulated odontoblasts, but also in adjacent odontoblasts. We could not observe these responses in the absence of extracellular Ca2+. [Ca2+]i increases in the neighboring odontoblasts during mechanical stimulation of single odontoblasts were inhibited by antagonists of metabotropic glutamate receptors (mGluRs) as well as glutamate-permeable anion channels. In the odontoblast-TG neuron coculture, we observed an increase in [Ca2+]i in the stimulated odontoblasts and TG neurons, in response to direct mechanical stimulation of single odontoblasts. These [Ca2+]i increases in the neighboring TG neurons were inhibited by antagonists for mGluRs. The [Ca2+]i increases in the stimulated odontoblasts were also inhibited by mGluRs antagonists. We further confirmed that the odontoblasts express group I, II, and III mGluRs. However, we could not record any currents evoked from odontoblasts near the mechanically stimulated odontoblast, with or without extracellular Mg2+, indicating that N-methyl-d-aspartic acid receptor does not contribute to inter-odontoblast signal communication. The results suggest that a mechanically stimulated odontoblast is capable of releasing glutamate into the extracellular space via glutamate-permeable anion channels. The released glutamate activates mGluRs on the odontoblasts in an autocrine/paracrine manner, forming an inter-odontoblasts communication, which drives dentin formation via odontoblast-odontoblast signal communication. Glutamate and mGluRs also mediate neurotransmission between the odontoblasts and neurons in the dental pulp to modulate sensory signal transmission for dentinal sensitivity.
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Affiliation(s)
- A Nishiyama
- Department of Oral Pathobiological Science and Surgery, Tokyo Dental College, Tokyo 101-0061, Japan
| | - M Sato
- Department of Physiology, Tokyo Dental College, Tokyo 101-0061, Japan
| | - M Kimura
- Department of Physiology, Tokyo Dental College, Tokyo 101-0061, Japan
| | - A Katakura
- Department of Oral Pathobiological Science and Surgery, Tokyo Dental College, Tokyo 101-0061, Japan
| | - M Tazaki
- Department of Physiology, Tokyo Dental College, Tokyo 101-0061, Japan
| | - Y Shibukawa
- Department of Physiology, Tokyo Dental College, Tokyo 101-0061, Japan.
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Ikeda E, Goto T, Gunjigake K, Kuroishi K, Ueda M, Kataoka S, Toyono T, Nakatomi M, Seta Y, Kitamura C, Nishihara T, Kawamoto T. Expression of Vesicular Nucleotide Transporter in Rat Odontoblasts. Acta Histochem Cytochem 2016; 49:21-8. [PMID: 27006518 PMCID: PMC4794551 DOI: 10.1267/ahc.15022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 11/25/2015] [Indexed: 01/29/2023] Open
Abstract
Several theories have been proposed regarding pain transmission mechanisms in tooth. However, the exact signaling mechanism from odontoblasts to pulp nerves remains to be clarified. Recently, ATP-associated pain transmission has been reported, but it is unclear whether ATP is involved in tooth pain transmission. In the present study, we focused on the vesicular nucleotide transporter (VNUT), a transporter of ATP into vesicles, and examined whether VNUT was involved in ATP release from odontoblasts. We examined the expression of VNUT in rat pulp by RT-PCR and immunostaining. ATP release from cultured odontoblast-like cells with heat stimulation was evaluated using ATP luciferase methods. VNUT was expressed in pulp tissue, and the distribution of VNUT-immunopositive vesicles was confirmed in odontoblasts. In odontoblasts, some VNUT-immunopositive vesicles were colocalized with membrane fusion proteins. Additionally P2X3, an ATP receptor, immunopositive axons were distributed between odontoblasts. The ATP release by thermal stimulation from odontoblast-like cells was inhibited by the addition of siRNA for VNUT. These findings suggest that cytosolic ATP is transported by VNUT and that the ATP in the vesicles is then released from odontoblasts to ATP receptors on axons. ATP vesicle transport in odontoblasts seems to be a key mechanism for signal transduction from odontoblasts to axons in the pulp.
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Affiliation(s)
- Erina Ikeda
- Division of Orofacial Functions and Orthodontics, Kyushu Dental University
| | - Tetsuya Goto
- Department of Oral Anatomy and Cell Biology, Kagoshima University
| | - Kaori Gunjigake
- Division of Orofacial Functions and Orthodontics, Kyushu Dental University
| | - Kayoko Kuroishi
- Division of Orofacial Functions and Orthodontics, Kyushu Dental University
| | - Masae Ueda
- Division of Orofacial Functions and Orthodontics, Kyushu Dental University
| | | | | | | | - Yuji Seta
- Division of Anatomy, Kyushu Dental University
| | - Chiaki Kitamura
- Division of Endodontics and Restorative Dentistry, Kyushu Dental University
| | - Tatsuji Nishihara
- Division of Infections and Molecular Biology, Kyushu Dental University
| | - Tatsuo Kawamoto
- Division of Orofacial Functions and Orthodontics, Kyushu Dental University
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Sato M, Furuya T, Kimura M, Kojima Y, Tazaki M, Sato T, Shibukawa Y. Intercellular Odontoblast Communication via ATP Mediated by Pannexin-1 Channel and Phospholipase C-coupled Receptor Activation. Front Physiol 2015; 6:326. [PMID: 26617529 PMCID: PMC4639624 DOI: 10.3389/fphys.2015.00326] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/27/2015] [Indexed: 11/13/2022] Open
Abstract
Extracellular ATP released via pannexin-1 channels, in response to the activation of mechanosensitive-TRP channels during odontoblast mechanical stimulation, mediates intercellular communication among odontoblasts in dental pulp slice preparation dissected from rat incisor. Recently, odontoblast cell lines, such as mouse odontoblast lineage cells, have been widely used to investigate physiological/pathological cellular functions. To clarify whether the odontoblast cell lines also communicate with each other by diffusible chemical substance(s), we investigated the chemical intercellular communication among cells from mouse odontoblast cell lines following mechanical stimulation. A single cell was stimulated using a glass pipette filled with standard extracellular solution. We measured intracellular free Ca(2+) concentration ([Ca(2+)]i) by fura-2 in stimulated cells, as well as in cells located nearby. Direct mechanical stimulation to a single odontoblast increased [Ca(2+)]i, which showed sensitivity to capsazepine. In addition, we observed increases in [Ca(2+)]i not only in the mechanically stimulated odontoblast, but also in nearby odontoblasts. We could observe mechanical stimulation-induced increase in [Ca(2+)]i in a stimulated human embryo kidney (HEK) 293 cell, but not in nearby HEK293 cells. The increase in [Ca(2+)]i in nearby odontoblasts, but not in the stimulated odontoblast, was inhibited by adenosine triphosphate (ATP) release channel (pannexin-1) inhibitor in a concentration- and spatial-dependent manner. Moreover, in the presence of phospholipase C (PLC) inhibitor, the increase in [Ca(2+)]i in nearby odontoblasts, following mechanical stimulation of a single odontoblast, was abolished. We could record some inward currents evoked from odontoblasts near the stimulated odontoblast, but the currents were observed in only 4.8% of the recorded odontoblasts. The results of this study showed that ATP is released via pannexin-1, from a mechanically stimulated odontoblast, which transmits a signal to nearby odontoblasts by predominant activation of PLC-coupled nucleotide receptors.
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Affiliation(s)
- Masaki Sato
- Department of Physiology, Tokyo Dental College Tokyo, Japan
| | - Tadashi Furuya
- Department of Physiology, Tokyo Dental College Tokyo, Japan ; Department of Crown and Bridge Prosthodontics, Tokyo Dental College Tokyo, Japan
| | - Maki Kimura
- Department of Physiology, Tokyo Dental College Tokyo, Japan
| | - Yuki Kojima
- Department of Physiology, Tokyo Dental College Tokyo, Japan
| | | | - Toru Sato
- Department of Crown and Bridge Prosthodontics, Tokyo Dental College Tokyo, Japan
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