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Yang DW, Shim HM, Kim MS, Kim SH. Spatiotemporal regulation of dental pulpal innervation in the rat. Anat Histol Embryol 2024; 53:e13093. [PMID: 39056435 DOI: 10.1111/ahe.13093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 07/01/2024] [Accepted: 07/10/2024] [Indexed: 07/28/2024]
Abstract
The dental pulp is a highly innervated tissue transmitting pain-related sensations in the tooth. Consequently, understanding the intricacies of its innervation mechanism in odontogenesis is crucial for gaining insights into dental pain and developing dental pain-modulating agents. This study examined neuroregulatory molecules such as neurotrophic factors (nerve growth factor [NGF], brain-derived neurotrophic factor [BDNF], neurotrophin-4 [NTF-4], and neurturin [NRTN]) and neuroinhibitory factors (slit2, ephrin isoforms and netrin-1) in developing rat teeth with follicles. NGF, BDNF and NRTN transcriptions showed time-dependent upregulation, particularly during the root formation stage. In contrast, NTF-4 mRNA was highly expressed at the cap stage, but became downregulated over time. Slit2 and ephrin-B2 expression was distinct at the cap stage and then downregulated in a time-dependent manner. Ephrin-A5 and netrin-1 expression did not significantly change. Immunofluorescence analysis revealed a robust expression of both ephrin-B2 and slit2 in the outer and inner dental epithelia of the enamel organ, a non-neurogenic tissue, during the cap stage of 3rd molar germs. In contrast, BDNF was predominantly localized in dental papilla cells and odontoblasts during the root formation stage. These results suggest that neuroregulatory molecules, such as BDNF, slit2 and ephrin-B2, may be important in identifying therapeutic targets for modulating dental pulp pain.
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Affiliation(s)
- Dong-Wook Yang
- Department of Oral Anatomy, Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
| | - Hye-Min Shim
- Department of Oral Anatomy, Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
| | - Min-Seok Kim
- Department of Oral Anatomy, Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
| | - Sun-Hun Kim
- Department of Oral Anatomy, Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
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Wang S, Ko CC, Chung MK. Nociceptor mechanisms underlying pain and bone remodeling via orthodontic forces: toward no pain, big gain. FRONTIERS IN PAIN RESEARCH 2024; 5:1365194. [PMID: 38455874 PMCID: PMC10917994 DOI: 10.3389/fpain.2024.1365194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 02/12/2024] [Indexed: 03/09/2024] Open
Abstract
Orthodontic forces are strongly associated with pain, the primary complaint among patients wearing orthodontic braces. Compared to other side effects of orthodontic treatment, orthodontic pain is often overlooked, with limited clinical management. Orthodontic forces lead to inflammatory responses in the periodontium, which triggers bone remodeling and eventually induces tooth movement. Mechanical forces and subsequent inflammation in the periodontium activate and sensitize periodontal nociceptors and produce orthodontic pain. Nociceptive afferents expressing transient receptor potential vanilloid subtype 1 (TRPV1) play central roles in transducing nociceptive signals, leading to transcriptional changes in the trigeminal ganglia. Nociceptive molecules, such as TRPV1, transient receptor potential ankyrin subtype 1, acid-sensing ion channel 3, and the P2X3 receptor, are believed to mediate orthodontic pain. Neuropeptides such as calcitonin gene-related peptides and substance P can also regulate orthodontic pain. While periodontal nociceptors transmit nociceptive signals to the brain, they are also known to modulate alveolar bone remodeling in periodontitis. Therefore, periodontal nociceptors and nociceptive molecules may contribute to the modulation of orthodontic tooth movement, which currently remains undetermined. Future studies are needed to better understand the fundamental mechanisms underlying neuroskeletal interactions in orthodontics to improve orthodontic treatment by developing novel methods to reduce pain and accelerate orthodontic tooth movement-thereby achieving "big gains with no pain" in clinical orthodontics.
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Affiliation(s)
- Sheng Wang
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, United States
| | - Ching-Chang Ko
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, United States
| | - Man-Kyo Chung
- Department of Neural and Pain Sciences, School of Dentistry, University of Maryland Baltimore, Baltimore, MD, United States
- Center to Advance Chronic Pain Research, University of Maryland Baltimore, Baltimore, MD, United States
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Wang C, Liu X, Zhou J, Zhang Q. The Role of Sensory Nerves in Dental Pulp Homeostasis: Histological Changes and Cellular Consequences after Sensory Denervation. Int J Mol Sci 2024; 25:1126. [PMID: 38256202 PMCID: PMC10815945 DOI: 10.3390/ijms25021126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 01/24/2024] Open
Abstract
Homeostatic maintenance is essential for pulp function. Disrupting pulp homeostasis may lead to pulp degeneration, such as fibrosis and calcifications. Sensory nerves constitute a crucial component of the dental pulp. However, the precise involvement of sensory nerves in pulp homeostasis remains uncertain. In this study, we observed the short-term and long-term histological changes in the dental pulp after inferior alveolar nerve transection. Additionally, we cultured primary dental pulp cells (DPCs) from the innervated and denervated groups and compared indicators of cellular senescence and cellular function. The results revealed that pulp fibrosis occurred at 2 w after the operation. Furthermore, the pulp area, as well as the height and width of the pulp cavity, showed accelerated reductions after sensory denervation. Notably, the pulp area at 16 w after the operation was comparable to that of 56 w old rats. Sensory denervation induced excessive extracellular matrix (ECM) deposition and increased predisposition to mineralization. Furthermore, sensory denervation promoted the senescence of DPCs. Denervated DPCs exhibited decelerated cell proliferation, arrest in the G2/M phase of the cell cycle, imbalance in the synthesis and degradation of ECM, and enhanced mineralization. These findings indicate that sensory nerves play an essential role in pulp homeostasis maintenance and dental pulp cell fate decisions, which may provide novel insights into the prevention of pulp degeneration.
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Affiliation(s)
| | | | | | - Qi Zhang
- Department of Endodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, No.399 Yanchang Middle Road, Jing’an District, Shanghai 200072, China
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Menon N, Kishen A. Nociceptor-Macrophage Interactions in Apical Periodontitis: How Biomolecules Link Inflammation with Pain. Biomolecules 2023; 13:1193. [PMID: 37627258 PMCID: PMC10452348 DOI: 10.3390/biom13081193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023] Open
Abstract
Periradicular tissues have a rich supply of peripheral afferent neurons, also known as nociceptive neurons, originating from the trigeminal nerve. While their primary function is to relay pain signals to the brain, these are known to be involved in modulating innate and adaptive immunity by initiating neurogenic inflammation (NI). Studies have investigated neuroanatomy and measured the levels of biomolecules such as cytokines and neuropeptides in human saliva, gingival crevicular fluid, or blood/serum samples in apical periodontitis (AP) to validate the possible role of trigeminal nociceptors in inflammation and tissue regeneration. However, the contributions of nociceptors and the mechanisms involved in the neuro-immune interactions in AP are not fully understood. This narrative review addresses the complex biomolecular interactions of trigeminal nociceptors with macrophages, the effector cells of the innate immune system, in the clinical manifestations of AP.
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Affiliation(s)
| | - Anil Kishen
- Dental Research Institute, Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada;
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Deng Y, Luo N, Xie M, He L, Jiang R, Hu N, Wen J, Jiang X. Transcriptome landscape comparison of periodontium in developmental and renewal stages. Front Endocrinol (Lausanne) 2023; 14:1154931. [PMID: 37008900 PMCID: PMC10050752 DOI: 10.3389/fendo.2023.1154931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 02/22/2023] [Indexed: 03/17/2023] Open
Abstract
OBJECTIVES Periodontium regeneration remains a significant challenge in clinics and research, and it is essential to understand the stage-specific biological process in situ. However, differing findings have been reported, and the mechanism has yet to be elucidated. The periodontium of adult mice molars is considered to be stable remodeling tissue. At the same time, the continuously growing incisors and the developing dental follicle (DF) of postnatal mice highly represent fast remodeling tissue. In this study, we attempted to explore different clues of temporal and spatial comparisons to provide improved references for periodontal regeneration. METHODS Periodontal tissues from the developing periodontium (DeP) of postnatal mice, and continuously growing periodontium (CgP) and stable remodeling periodontium (ReP) of adult mice were isolated and compared using RNA sequencing. Based on the Dep and CgP separately compared with the ReP, differentially expressed genes and signaling pathways were analyzed using GO, KEGG databases, and Ingenuity Pathway Analysis (IPA). The results and validation were obtained by immunofluorescence staining and RT-PCR assays. Data were expressed as means ± standard deviation (SD) and analyzed by GraphPad Prism 8 software package, and one-way ANOVA was used to test multiple groups. RESULTS Principal component analysis showed that the three groups of periodontal tissue were successfully isolated and had distinct expression profiles. A total of 792 and 612 DEGs were identified in the DeP and CgP groups compared with the ReP. Upregulated DEGs in the DeP were closely related to developmental processes, while the CgP showed significantly enhanced cellular energy metabolism. The DeP and CgP showed a common downregulation of the immune response, with activation, migration, and recruitment of immune cells. IPA and further validation jointly suggested that the MyD88/p38 MAPK pathway played an essential regulatory role in periodontium remodeling. CONCLUSION Tissue development, energy metabolism, and immune response were critical regulatory processes during periodontal remodeling. Developmental and adult stages of periodontal remodeling showed different expression patterns. These results contribute to a deeper understanding of periodontal development and remodeling and may provide references for periodontal regeneration.
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Affiliation(s)
- Yuwei Deng
- Shanghai Engineering Research Center of Advanced Dental Technology and Materials, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Ninth People’s Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Prosthodontics, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Nan Luo
- Shanghai Engineering Research Center of Advanced Dental Technology and Materials, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Ninth People’s Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Preventive Dentistry, Ninth People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ming Xie
- Shanghai Engineering Research Center of Advanced Dental Technology and Materials, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Ninth People’s Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Prosthodontics, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ling He
- Department of Radiation Oncology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, United States
| | - Ruixue Jiang
- Shanghai Engineering Research Center of Advanced Dental Technology and Materials, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Ninth People’s Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Prosthodontics, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Nan Hu
- Shanghai Engineering Research Center of Advanced Dental Technology and Materials, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Ninth People’s Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Endodontics, Ninth People’ Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jin Wen
- Shanghai Engineering Research Center of Advanced Dental Technology and Materials, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Ninth People’s Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Prosthodontics, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Xinquan Jiang, ; Jin Wen,
| | - Xinquan Jiang
- Shanghai Engineering Research Center of Advanced Dental Technology and Materials, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Ninth People’s Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Prosthodontics, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Xinquan Jiang, ; Jin Wen,
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