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Cui Y, Bai M, Guo D, Yang Y, Chen H, Sun J, Xie J, Zhou X. Insulin-like growth factor 1 promotes neural differentiation of human stem cells from the apical papilla. Arch Oral Biol 2021; 131:105264. [PMID: 34598025 DOI: 10.1016/j.archoralbio.2021.105264] [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: 08/02/2021] [Revised: 09/09/2021] [Accepted: 09/11/2021] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Insulin-like growth factor 1 (IGF1) is one of the vital factors in regenerative endodontics. Previous studies have focused on the role of IGF1 in the mineralization of dental tissues. However, the role of IGF1 in the neural differentiation of dental stem cells was little discussed. DESIGN IGF1 was overexpressed in human stem cells from the apical papilla (hSCAPs) by lentivirus and knocked down in hSCAPs by small interfering RNA. The neural differentiation level of hSCAPs was investigated histologically by HE staining and Nissl staining after neural induction for 3 days. The expression of proteins was examined by western blot and immunofluorescence. RESULTS IGF1 promoted neural differentiation of hSCAPs, more cell processes and Nissl-positive body stained cells. IGF1 overexpression could both promote glial differentiation in hSCAPs, characterized by the increase of S100β and GFAP proteins, and neuronal differentiation, characterized by the increase of βIII-tubulin and functional GAD67/vGLUT1 proteins. Conversely, IGF1 knockdown suppressed both glial and neuronal differentiation. IGF1 activated AKT to regulate the early neural differentiation of hSCAPs. CONCLUSIONS The results indicate IGF1 could promote neural differentiation of hSCAPs by activating AKT signaling and provide a cue for the candidate of induced neural seeding cells in regenerative endodontics.
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Affiliation(s)
- Yujia Cui
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China; Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Mingru Bai
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China; Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Daimo Guo
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China; Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Yueyi Yang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China; Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Haoran Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China; Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Jianxun Sun
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China; Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China; Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
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Altaie AM, Venkatachalam T, Samaranayake LP, Soliman SSM, Hamoudi R. Comparative Metabolomics Reveals the Microenvironment of Common T-Helper Cells and Differential Immune Cells Linked to Unique Periapical Lesions. Front Immunol 2021; 12:707267. [PMID: 34539639 PMCID: PMC8446658 DOI: 10.3389/fimmu.2021.707267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 08/12/2021] [Indexed: 12/12/2022] Open
Abstract
Periapical abscesses, radicular cysts, and periapical granulomas are the most frequently identified pathological lesions in the alveolar bone. While little is known about the initiation and progression of these conditions, the metabolic environment and the related immunological behaviors were examined for the first time to model the development of each pathological condition. Metabolites were extracted from each lesion and profiled using gas chromatography-mass spectrometry in comparison with healthy pulp tissue. The metabolites were clustered and linked to their related immune cell fractions. Clusters I and J in the periapical abscess upregulated the expression of MMP-9, IL-8, CYP4F3, and VEGF, while clusters L and M were related to lipophagy and apoptosis in radicular cyst, and cluster P in periapical granuloma, which contains L-(+)-lactic acid and ethylene glycol, was related to granuloma formation. Oleic acid, 17-octadecynoic acid, 1-nonadecene, and L-(+)-lactic acid were significantly the highest unique metabolites in healthy pulp tissue, periapical abscess, radicular cyst, and periapical granuloma, respectively. The correlated enriched metabolic pathways were identified, and the related active genes were predicted. Glutamatergic synapse (16–20),-hydroxyeicosatetraenoic acids, lipophagy, and retinoid X receptor coupled with vitamin D receptor were the most significantly enriched pathways in healthy control, abscess, cyst, and granuloma, respectively. Compared with the healthy control, significant upregulation in the gene expression of CYP4F3, VEGF, IL-8, TLR2 (P < 0.0001), and MMP-9 (P < 0.001) was found in the abscesses. While IL-12A was significantly upregulated in cysts (P < 0.01), IL-17A represents the highest significantly upregulated gene in granulomas (P < 0.0001). From the predicted active genes, CIBERSORT suggested the presence of natural killer cells, dendritic cells, pro-inflammatory M1 macrophages, and anti-inflammatory M2 macrophages in different proportions. In addition, the single nucleotide polymorphisms related to IL-10, IL-12A, and IL-17D genes were shown to be associated with periapical lesions and other oral lesions. Collectively, the unique metabolism and related immune response shape up an environment that initiates and maintains the existence and progression of these oral lesions, suggesting an important role in diagnosis and effective targeted therapy.
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Affiliation(s)
- Alaa Muayad Altaie
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates.,Department of Oral and Craniofacial Health Sciences, College of Dental Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Thenmozhi Venkatachalam
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Lakshman P Samaranayake
- Department of Oral and Craniofacial Health Sciences, College of Dental Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Department of Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong, Hong Kong, SAR China
| | - Sameh S M Soliman
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates.,Department of Medicinal Chemistry, College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates
| | - Rifat Hamoudi
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates.,Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Division of Surgery and Interventional Science, University College London, London, United Kingdom
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Cho YS, Ko HG, Han HM, Park SK, Moozhayil SJ, Choi SY, Bae YC. Vesicular glutamate transporter-immunopositive axons that coexpress neuropeptides in the rat and human dental pulp. Int Endod J 2020; 54:377-387. [PMID: 33090483 DOI: 10.1111/iej.13427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 12/17/2022]
Abstract
AIM To examine the type of vesicular glutamate transporter (VGLUT)-immunopositive (+) axons that coexpress neuropeptides in the rat and human dental pulp, which may help understand peripheral mechanism of pulpal inflammatory pain in rats and humans. METHODOLOGY The trigeminal ganglia (TG) and the dental pulp of the maxillary molar teeth from three male Sprague-Dawley rats weighing 300-330 g and dental pulps of three healthy human (male) maxillary premolar teeth from three 16 to 28-year-old patients extracted for orthodontic treatment were used. The type of VGLUT + axons that coexpress substance P (SP)- and/or calcitonin gene-related peptide (CGRP) and parvalbumin in the rat TG and in the axons of the rat and the human dental pulp was examined by double fluorescence immunohistochemistry and quantitative analysis. Results were analyzed using one-way anova and the Kruskal-Wallis test. RESULTS SP and CGRP were expressed in many human VGLUT1 + pulpal axons but not in the rat VGLUT1 + TG neurons and pulpal axons (P < 0.05). SP and CGRP were expressed in a considerable number of human VGLUT2 + pulpal axons and also in many rat TG neurons and pulpal axons. The fraction of VGLUT1 + axons expressing parvalbumin was about three times higher in the rat than in the human dental pulp (P < 0.05). CONCLUSIONS These findings suggest that the types of VGLUT + axons, which release neuropeptides, may be different between the rat and the human dental pulp, raising a possibility that peripheral mechanism of pulpal inflammatory pain may be different between rats and humans.
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Affiliation(s)
- Y S Cho
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - H G Ko
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - H M Han
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - S K Park
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - S J Moozhayil
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - S Y Choi
- Department of Oral & Maxillofacial Surgery, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Y C Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
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Parvalbumin-, substance P- and calcitonin gene-related peptide-immunopositive axons in the human dental pulp differ in their distribution of varicosities. Sci Rep 2020; 10:10672. [PMID: 32606338 PMCID: PMC7327034 DOI: 10.1038/s41598-020-67804-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/11/2020] [Indexed: 11/17/2022] Open
Abstract
Information on the frequency and spatial distribution of axonal varicosities associated with release of neurotransmitters in the dental pulp is important to help elucidate the peripheral mechanisms of dental pain, mediated by myelinated versus unmyelinated fibers. For this, we investigated the distribution of axonal varicosities in the human dental pulp using light- and electron-microscopic immunohistochemistry for the vesicular glutamate transporter 2 (VGLUT2), which is involved in the glutamatergic transmission, and syntaxin-1 and synaptosomal nerve-associated protein 25 (SNAP-25), combined with parvalbumin (PV), which is expressed mostly in myelinated axons, and substance P (SP) and calcitonin gene-related peptide (CGRP), which are expressed mostly in unmyelinated axons. We found that the varicosities of the SP- and CGRP-immunopositive (+) axons were uniformly distributed throughout the dental pulp, whereas those of PV+ axons were only dense in the peripheral pulp, and that the expression of PV, VGLUT2, syntaxin-1, SNAP-25, SP and CGRP was significantly higher in the varicosities than in the axonal segments between them. These findings are consistent with the release of glutamate and neuropeptides by axonal varicosities of SP+ and CGRP+ unmyelinated fibers, involved in pulpal pain throughout the human dental pulp, and by varicosities of PV+ fibers, arising from parent myelinated fibers, and involved in dentin sensitivity primarily in the peripheral pulp.
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Affiliation(s)
- Yong-Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University
| | - Atsushi Yoshida
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University
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Zhang FX, Ge SN, Dong YL, Shi J, Feng YP, Li Y, Li YQ, Li JL. Vesicular glutamate transporter isoforms: The essential players in the somatosensory systems. Prog Neurobiol 2018; 171:72-89. [PMID: 30273635 DOI: 10.1016/j.pneurobio.2018.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/28/2018] [Accepted: 09/23/2018] [Indexed: 02/08/2023]
Abstract
In nervous system, glutamate transmission is crucial for centripetal conveyance and cortical perception of sensory signals of different modalities, which necessitates vesicular glutamate transporters 1-3 (VGLUT 1-3), the three homologous membrane-bound protein isoforms, to load glutamate into the presysnaptic vesicles. These VGLUTs, especially VGLUT1 and VGLUT2, selectively label and define functionally distinct neuronal subpopulations at each relay level of the neural hierarchies comprising spinal and trigeminal sensory systems. In this review, by scrutinizing each structure of the organism's fundamental hierarchies including dorsal root/trigeminal ganglia, spinal dorsal horn/trigeminal sensory nuclear complex, somatosensory thalamic nuclei and primary somatosensory cortex, we summarize and characterize in detail within each relay the neuronal clusters expressing distinct VGLUT protein/transcript isoforms, with respect to their regional distribution features (complementary distribution in some structures), axonal terminations/peripheral innervations and physiological functions. Equally important, the distribution pattern and characteristics of VGLUT1/VGLUT2 axon terminals within these structures are also epitomized. Finally, the correlation of a particular VGLUT isoform and its physiological role, disclosed thus far largely via studying the peripheral receptors, is generalized by referring to reports on global and conditioned VGLUT-knockout mice. Also, researches on VGLUTs relating to future direction are tentatively proposed, such as unveiling the elusive differences between distinct VGLUTs in mechanism and/or pharmacokinetics at ionic/molecular level, and developing VGLUT-based pain killers.
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Affiliation(s)
- Fu-Xing Zhang
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Shun-Nan Ge
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China; Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - Yu-Lin Dong
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Juan Shi
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Yu-Peng Feng
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Yang Li
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - Yun-Qing Li
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, PR China.
| | - Jin-Lian Li
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China.
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Vesicular glutamate transporter 1 (VGLUT1)- and VGLUT2-immunopositive axon terminals on the rat jaw-closing and jaw-opening motoneurons. Brain Struct Funct 2018; 223:2323-2334. [DOI: 10.1007/s00429-018-1636-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 02/19/2018] [Indexed: 12/16/2022]
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Kim TH, Park SK, Choi SY, Lee JS, Bae YC. Morphologic Change of Parvalbumin-positive Myelinated Axons in the Human Dental Pulp. J Endod 2017; 43:977-981. [PMID: 28389070 DOI: 10.1016/j.joen.2017.01.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 12/22/2016] [Accepted: 01/09/2017] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Information on the nerve fibers innervating the dental pulp is crucial for understanding dental pain and hypersensitivity. This study investigated the morphologic differences of parvalbumin (PV)-positive (+) myelinated fibers in 3 different regions of the human dental pulp. METHODS Light and electron microscopic immunohistochemistry for parvalbumin, a marker for myelinated fibers, and quantitative analysis were performed in the apical root, core of coronal pulp, and peripheral pulp of human premolar teeth. RESULTS About 40% of the myelinated fibers in the apical root pulp became unmyelinated in the core of the coronal pulp, and virtually all the remaining fibers became unmyelinated at the peripheral pulp. The size of myelinated axons decreased from root to peripheral pulp. PV+ axons showed extensive axonal varicosities in the peripheral pulp. CONCLUSIONS These findings suggest that the myelinated fibers innervating the human dental pulp undergo extensive morphologic change in the extrapulpal region and in the coronal and peripheral pulp, and that PV-mediated regulation of calcium concentration and its downstream events may occur primarily in axonal varicosities in the peripheral pulp.
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Affiliation(s)
- Tae Heon Kim
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Sook Kyung Park
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - So Young Choi
- Department of Oral & Maxillofacial Surgery, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Jae Sik Lee
- Department of Pediatric Dentistry, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea.
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Honma S, Kadono K, Kawano A, Wakisaka S. Immunohistochemical localization of SNARE core proteins in intrapulpal and intradentinal nerve fibers of rat molar teeth. Arch Oral Biol 2017; 73:248-252. [DOI: 10.1016/j.archoralbio.2016.10.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 10/15/2016] [Accepted: 10/24/2016] [Indexed: 11/29/2022]
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Cho YA, Kim DS, Song M, Bae WJ, Lee S, Kim EC. Protein Interacting with Never in Mitosis A-1 Induces Glutamatergic and GABAergic Neuronal Differentiation in Human Dental Pulp Stem Cells. J Endod 2016; 42:1055-61. [PMID: 27178251 DOI: 10.1016/j.joen.2016.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 03/28/2016] [Accepted: 04/02/2016] [Indexed: 01/09/2023]
Abstract
INTRODUCTION The purpose of this study was to investigate the role of protein interacting with never in mitosis A-1 (PIN1) in the neuronal or glial differentiation of human dental pulp stem cells (hDPSCs) and whether PIN1 can regulate determination of neuronal sub-phenotype. METHODS After magnetic-activated cell sorting to separate CD34(+)/c-kit(+)/STRO-1(+) hDPSCs, cells were cultured in neurogenic medium. Differentiation was measured as Nissl staining and marker protein or mRNA expression by reverse transcriptase polymerase chain reaction, immunofluorescence, and flow cytometric analysis. RESULTS PIN1 mRNA levels were upregulated in a time-dependent fashion during neurogenic differentiation. The PIN1 inhibitor juglone suppressed neuronal differentiation but promoted glial differentiation as assessed by the number of Nissl-positive cells and mRNA expression of neuronal markers (nestin, βIII-tubulin, and NeuN) and a glial marker (glial fibrillary acidic protein). Conversely, overexpression of PIN1 by infection with adenovirus-PIN1 increased neuronal differentiation but decreased glial differentiation. Moreover, PIN1 overexpression increased the percentage of glutamatergic and GABAergic cells but decreased that of dopaminergic cells among total NeuN-positive hDPSCs. CONCLUSIONS This is the first study to demonstrate that PIN1 overexpression induced glutamatergic and GABAergic neuronal differentiation but suppressed glial differentiation of hDPSCs, suggesting that enhancing PIN expression is important to obtain human glutamatergic and GABAergic neurons from hDPSCs.
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Affiliation(s)
- Young-Ah Cho
- Department of Oral and Maxillofacial Pathology and Research Center for Tooth and Periodontal Tissue Regeneration (MRC), School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Duck-Su Kim
- Department of Conservative Dentistry, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Miyeoun Song
- Department of Oral and Maxillofacial Pathology and Research Center for Tooth and Periodontal Tissue Regeneration (MRC), School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Won-Jung Bae
- Department of Oral and Maxillofacial Pathology and Research Center for Tooth and Periodontal Tissue Regeneration (MRC), School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Soojung Lee
- Department of Oral Physiology, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Eun-Cheol Kim
- Department of Oral and Maxillofacial Pathology and Research Center for Tooth and Periodontal Tissue Regeneration (MRC), School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
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Kim YS, Kim TH, McKemy DD, Bae YC. Expression of vesicular glutamate transporters in transient receptor potential melastatin 8 (TRPM8)-positive dental afferents in the mouse. Neuroscience 2015; 303:378-88. [PMID: 26166724 DOI: 10.1016/j.neuroscience.2015.07.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/01/2015] [Accepted: 07/02/2015] [Indexed: 01/31/2023]
Abstract
Transient receptor potential melastatin 8 (TRPM8) is activated by innocuous cool and noxious cold and plays a crucial role in cold-induced acute pain and pain hypersensitivity. To help understand the mechanism of TRPM8-mediated cold perception under normal and pathologic conditions, we used light microscopic immunohistochemistry and Western blot analysis in mice expressing a genetically encoded axonal tracer in TRPM8-positive (+) neurons. We investigated the coexpression of TRPM8 and vesicular glutamate transporter 1 (VGLUT1) and VGLUT2 in the trigeminal ganglion (TG) and the dental pulp before and after inducing pulpal inflammation. Many TRPM8+ neurons in the TG and axons in the dental pulp expressed VGLUT2, while none expressed VGLUT1. TRPM8+ axons were dense in the pulp horn and peripheral pulp and also frequently observed in the dentinal tubules. Following pulpal inflammation, the proportion of VGLUT2+ and of VGLUT2+/TRPM8+ neurons increased significantly, whereas that of TRPM8+ neurons remained unchanged. Our findings suggest the existence of VGLUT2 (but not VGLUT1)-mediated glutamate signaling in TRPM8+ neurons possibly underlying the cold-induced acute pain and hypersensitivity to cold following pulpal inflammation.
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Affiliation(s)
- Y S Kim
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, South Korea
| | - T H Kim
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, South Korea
| | - D D McKemy
- Neurobiology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Y C Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, South Korea.
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Cho Y, Kim Y, Moozhayil S, Yang E, Bae Y. The expression of hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1) and HCN2 in the rat trigeminal ganglion, sensory root, and dental pulp. Neuroscience 2015; 291:15-25. [DOI: 10.1016/j.neuroscience.2015.01.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 10/24/2022]
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Expression of vesicular glutamate transporters VGLUT1 and VGLUT2 in the rat dental pulp and trigeminal ganglion following inflammation. PLoS One 2014; 9:e109723. [PMID: 25290694 PMCID: PMC4188624 DOI: 10.1371/journal.pone.0109723] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 09/04/2014] [Indexed: 01/07/2023] Open
Abstract
Background There is increasing evidence that peripheral glutamate signaling mechanism is involved in the nociceptive transmission during pathological conditions. However, little is known about the glutamate signaling mechanism and related specific type of vesicular glutamate transporter (VGLUT) in the dental pulp following inflammation. To address this issue, we investigated expression and protein levels of VGLUT1 and VGLUT2 in the dental pulp and trigeminal ganglion (TG) following complete Freund’s adjuvant (CFA) application to the rat dental pulp by light microscopic immunohistochemistry and Western blot analysis. Results The density of VGLUT2− immunopositive (+) axons in the dental pulp and the number of VGLUT2+ soma in the TG increased significantly in the CFA-treated group, compared to control group. The protein levels of VGLUT2 in the dental pulp and TG were also significantly higher in the CFA-treated group than control group by Western blot analysis. The density of VGLUT1+ axons in the dental pulp and soma in the TG remained unchanged in the CFA-treated group. Conclusions These findings suggest that glutamate signaling that is mediated by VGLUT2 in the pulpal axons may be enhanced in the inflamed dental pulp, which may contribute to pulpal axon sensitization leading to hyperalgesia following inflammation.
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VGLUTs in Peripheral Neurons and the Spinal Cord: Time for a Review. ISRN NEUROLOGY 2013; 2013:829753. [PMID: 24349795 PMCID: PMC3856137 DOI: 10.1155/2013/829753] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/25/2013] [Indexed: 02/07/2023]
Abstract
Vesicular glutamate transporters (VGLUTs) are key molecules for the incorporation of glutamate in synaptic vesicles across the nervous system, and since their discovery in the early 1990s, research on these transporters has been intense and productive. This review will focus on several aspects of VGLUTs research on neurons in the periphery and the spinal cord. Firstly, it will begin with a historical account on the evolution of the morphological analysis of glutamatergic systems and the pivotal role played by the discovery of VGLUTs. Secondly, and in order to provide an appropriate framework, there will be a synthetic description of the neuroanatomy and neurochemistry of peripheral neurons and the spinal cord. This will be followed by a succinct description of the current knowledge on the expression of VGLUTs in peripheral sensory and autonomic neurons and neurons in the spinal cord. Finally, this review will address the modulation of VGLUTs expression after nerve and tissue insult, their physiological relevance in relation to sensation, pain, and neuroprotection, and their potential pharmacological usefulness.
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