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Li W, Sun W, Zhang G, Lu Y, Dai C. Thermosensitive hydrogel containing ethosuximide-loaded multivesicular liposomes attenuates age-related hearing loss in C57BL/6J mice. Neurosci Lett 2024; 826:137693. [PMID: 38428726 DOI: 10.1016/j.neulet.2024.137693] [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: 12/05/2023] [Revised: 01/20/2024] [Accepted: 02/13/2024] [Indexed: 03/03/2024]
Abstract
Ethosuximide is the first drug reported to protect against age-related hearing loss, but its benefits are hampered by the pronounced side effects generated through systemic administration. We prepared a thermosensitive hydrogel containing ethosuximide-encapsulated multivesicular liposomes (ethosuximide-loaded MVLs-Gel) and evaluated its functional and histological effects on age-related hearing loss in C57BL/6J mice. The MVLs-Gel showed slow sustained-release characteristics up to over 120 h. After 8 weeks of treatment, compared to the oral systemic administration of ethosuximide, intratympanic ethosuximide-loaded MVLs-Gel injection dramatically reduced the loss of age-related spiral ganglion neurons in the apical turns of the mice (low-frequency regions, p < 0.05). Correspondingly, compared to the oral systemic administration group, the intratympanic ethosuximide-loaded MVLs-Gel injection group showed significantly lower auditory brainstem response threshold shifts at stimulus frequencies of 4, 8, and 16 kHz (low-and middle-frequency regions, p < 0.05). In conclusion, intratympanic ethosuximide-loaded MVLs-Gel injection can reach the apical turn of the cochlea, which is extremely difficult with oral systemic administration of the drug. The ethosuximide-loaded MVLs-Gel, as a novel intratympanic sustained-release drug delivery system, attenuated age-related hearing loss in C57BL/6J mice.
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Affiliation(s)
- Wei Li
- Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai, China; Key Laboratory of Hearing Medicine, Ministry of Health, Shanghai, China
| | - Wenfang Sun
- Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai, China; Key Laboratory of Hearing Medicine, Ministry of Health, Shanghai, China
| | - Guoming Zhang
- Department of Otolaryngology, Yuecheng District People's Hospital, Shaoxing, China
| | - Yi Lu
- School of Pharmacy, Fudan University, Shanghai, China.
| | - Chunfu Dai
- Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai, China; Key Laboratory of Hearing Medicine, Ministry of Health, Shanghai, China.
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2
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Herb M. NADPH Oxidase 3: Beyond the Inner Ear. Antioxidants (Basel) 2024; 13:219. [PMID: 38397817 PMCID: PMC10886416 DOI: 10.3390/antiox13020219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Reactive oxygen species (ROS) were formerly known as mere byproducts of metabolism with damaging effects on cellular structures. The discovery and description of NADPH oxidases (Nox) as a whole enzyme family that only produce this harmful group of molecules was surprising. After intensive research, seven Nox isoforms were discovered, described and extensively studied. Among them, the NADPH oxidase 3 is the perhaps most underrated Nox isoform, since it was firstly discovered in the inner ear. This stigma of Nox3 as "being only expressed in the inner ear" was also used by me several times. Therefore, the question arose whether this sentence is still valid or even usable. To this end, this review solely focuses on Nox3 and summarizes its discovery, the structural components, the activating and regulating factors, the expression in cells, tissues and organs, as well as the beneficial and detrimental effects of Nox3-mediated ROS production on body functions. Furthermore, the involvement of Nox3-derived ROS in diseases progression and, accordingly, as a potential target for disease treatment, will be discussed.
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Affiliation(s)
- Marc Herb
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine, University Hospital Cologne, University of Cologne, 50935 Cologne, Germany;
- German Centre for Infection Research, Partner Site Bonn-Cologne, 50931 Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Aging-Associated Diseases (CECAD), 50931 Cologne, Germany
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Tavanai E, Rahimi V, Khalili ME, Falahzadeh S, Motasaddi Zarandy M, Mohammadkhani G. Age-related hearing loss: An updated and comprehensive review of the interventions. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2024; 27:256-269. [PMID: 38333758 PMCID: PMC10849199 DOI: 10.22038/ijbms.2023.72863.15849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 07/17/2023] [Indexed: 02/10/2024]
Abstract
Aging causes progressive degenerative changes in many organs, particularly the auditory system. Several attempts have been conducted to investigate preventive and therapeutic strategy/strategies for age-related auditory dysfunction, such as maintaining a healthy lifestyle through good nutrition, lower anxiety levels, and noise exposure, different pharmacological approaches, gene and cell therapy, and other strategies. However, it is not clear which approach is the best to slow down these dysfunctions because several different underlying mechanistic pathways are associated with presbycusis which eventually leads to different types of this disease. A combination of several methods is probably required, whereas the effectiveness for some people needs to be monitored. The effectiveness of treatments will not be the same for all; therefore, we may need to have a unique and personalized approach to the prevention and treatment of ARHL for each person. In addition, each method needs to specify what type of presbycusis can prevent or treat and provide complete information about the extent, duration of treatment, persistency of treatment, side effects, and whether the approach is for treatment or prevention or even both. This paper reviews the updated literature, which targets current interventions for age-related hearing loss.
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Affiliation(s)
- Elham Tavanai
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
| | - Vida Rahimi
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ehsan Khalili
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
| | - Somayeh Falahzadeh
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
- Department of Audiology, School of Rehabilitation, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Masoud Motasaddi Zarandy
- Otolaryngology Research Center, Amiralam Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ghassem Mohammadkhani
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
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Liu J, Chen H, Lin X, Zhu X, Huang J, Xu W, Tan M, Su J. Melatonin Suppresses Cyclic GMP-AMP Synthase-Stimulator of Interferon Genes Signaling and Delays the Development of Hearing Loss in the C57BL/6J Presbycusis Mouse Model. Neuroscience 2023; 517:84-95. [PMID: 36702373 DOI: 10.1016/j.neuroscience.2023.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 01/05/2023] [Accepted: 01/16/2023] [Indexed: 01/24/2023]
Abstract
Melatonin supplementation has been shown to delay age-related hearing loss (ARHL) progression. Previously, melatonin was found to inhibit neuronal mitochondrial DNA (mtDNA) release, as well as inhibit cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling, thereby delaying the onset of central nervous system diseases. Therefore, we hypothesized that melatonin may delay the progression of hearing loss in the C57BL/6J presbycusis mouse model by inhibiting cGAS-STING signaling in the auditory pathway. Oral melatonin at 10 mg/kg/d was administered to 3-month-old C57BL/6J mice until 12 months of age. The auditory brainstem response (ABR) threshold was used to assess their hearing ability. By real-time polymerase chain reaction and Western blot analysis, the levels of cytosolic mtDNA, cGAS/STING, and cytokines were examined in the mouse cochlea, inferior colliculus, and auditory cortex. We found that the 12-month-old control mice exhibited significant hearing loss, increased cytosolic mtDNA, increased expression of inflammatory factors TNF-α, IL-6, IFN-β, Cxcl10, and Ifit3, up-regulated cGAS and STING expression, and enhanced interferon regulatory factor 3 (IRF3) phosphorylation in the C57BL/6J mouse cochlea, inferior colliculus, and auditory cortex. Melatonin treatment significantly improved hearing, decreased cytosolic mtDNA, suppressed the expression of inflammatory cytokines TNF-α, IL-6, IFN-β, Ifit3, and Cxcl10, down-regulated cGAS and STING expression, and attenuated IRF3 phosphorylation in the C57BL/6J mouse cochlea, inferior colliculus, and auditory cortex. This study suggested that melatonin had a protective effect on auditory function in the C57BL/6J presbycusis mouse model, which may be mediated through reducing mtDNA release, inhibiting the cGAS-STING signaling pathway in the auditory pathway.
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Affiliation(s)
- Jinlan Liu
- Department of Otolaryngology-Head & Neck Surgery, First Afliated Hospital of Guangxi Medical University, Nanning, Guangxi, China; Department of Otolaryngology-Head & Neck Surgery, Guangxi International Zhuang Medicine Hospital, Nanning, Guangxi, China
| | - Huiying Chen
- Department of Otolaryngology-Head & Neck Surgery, First Afliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Xiaoyu Lin
- Department of Otolaryngology-Head & Neck Surgery, First Afliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Xiaoting Zhu
- Department of Otolaryngology-Head & Neck Surgery, First Afliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Jialin Huang
- Department of Otolaryngology-Head & Neck Surgery, First Afliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Wenfeng Xu
- Department of Otolaryngology-Head & Neck Surgery, First Afliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Ming Tan
- Department of Otolaryngology-Head & Neck Surgery, First Afliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Jiping Su
- Department of Otolaryngology-Head & Neck Surgery, First Afliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
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Vlajkovic SM, Thorne PR. Purinergic Signalling in the Cochlea. Int J Mol Sci 2022; 23:ijms232314874. [PMID: 36499200 PMCID: PMC9741428 DOI: 10.3390/ijms232314874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022] Open
Abstract
The mammalian cochlea is the sensory organ of hearing with a delicate, highly organised structure that supports unique operating mechanisms. ATP release from the secretory tissues of the cochlear lateral wall (stria vascularis) triggers numerous physiological responses by activating P2 receptors in sensory, supporting and neural tissues. Two families of P2 receptors, ATP-gated ion channels (P2X receptors) and G protein-coupled P2Y receptors, activate intracellular signalling pathways that regulate cochlear development, homeostasis, sensory transduction, auditory neurotransmission and response to stress. Of particular interest is a purinergic hearing adaptation, which reflects the critical role of the P2X2 receptor in adaptive cochlear response to elevated sound levels. Other P2 receptors are involved in the maturation of neural processes and frequency selectivity refinement in the developing cochlea. Extracellular ATP signalling is regulated by a family of surface-located enzymes collectively known as "ectonucleotidases" that hydrolyse ATP to adenosine. Adenosine is a constitutive cell metabolite with an established role in tissue protection and regeneration. The differential activation of A1 and A2A adenosine receptors defines the cochlear response to injury caused by oxidative stress, inflammation, and activation of apoptotic pathways. A1 receptor agonism, A2A receptor antagonism, and increasing adenosine levels in cochlear fluids all represent promising therapeutic tools for cochlear rescue from injury and prevention of hearing loss.
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Affiliation(s)
- Srdjan M. Vlajkovic
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Correspondence: ; Tel.: +64-9-9239782
| | - Peter R. Thorne
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Section of Audiology, School of Population Health, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Ma X, Guo J, Fu Y, Shen C, Jiang P, Zhang Y, Zhang L, Yu Y, Fan J, Chai R. G protein-coupled receptors in cochlea: Potential therapeutic targets for hearing loss. Front Mol Neurosci 2022; 15:1028125. [PMID: 36311029 PMCID: PMC9596917 DOI: 10.3389/fnmol.2022.1028125] [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: 08/25/2022] [Accepted: 09/21/2022] [Indexed: 11/29/2022] Open
Abstract
The prevalence of hearing loss-related diseases caused by different factors is increasing worldwide year by year. Currently, however, the patient’s hearing loss has not been effectively improved. Therefore, there is an urgent need to adopt new treatment measures and treatment techniques to help improve the therapeutic effect of hearing loss. G protein-coupled receptors (GPCRs), as crucial cell surface receptors, can widely participate in different physiological and pathological processes, particularly play an essential role in many disease occurrences and be served as promising therapeutic targets. However, no specific drugs on the market have been found to target the GPCRs of the cochlea. Interestingly, many recent studies have demonstrated that GPCRs can participate in various pathogenic process related to hearing loss in the cochlea including heredity, noise, ototoxic drugs, cochlear structure, and so on. In this review, we comprehensively summarize the functions of 53 GPCRs known in the cochlea and their relationships with hearing loss, and highlight the recent advances of new techniques used in cochlear study including cryo-EM, AI, GPCR drug screening, gene therapy vectors, and CRISPR editing technology, as well as discuss in depth the future direction of novel GPCR-based drug development and gene therapy for cochlear hearing loss. Collectively, this review is to facilitate basic and (pre-) clinical research in this area, and provide beneficial help for emerging GPCR-based cochlear therapies.
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Affiliation(s)
- Xiangyu Ma
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Jiamin Guo
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Yaoyang Fu
- Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Cangsong Shen
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Pei Jiang
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Yuan Zhang
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
- Research Institute of Otolaryngology, Nanjing, China
| | - Lei Zhang
- Department of Otorhinolaryngology, Head and Neck Surgery, The Second Hospital of Anhui Medical University, Hefei, China
| | - Yafeng Yu
- First Affiliated Hospital of Soochow University, Soochow, China
- *Correspondence: Yafeng Yu,
| | - Jiangang Fan
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Jiangang Fan,
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
- Renjie Chai,
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7
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Zhang J, Fan W, Neng L, Chen B, Wang Y, Zuo B, Lu W. Adenosine improves LPS-induced ROS expression and increasing in monolayer permeability of endothelial cell via acting on A2AR. Microvasc Res 2022; 143:104403. [PMID: 35753505 DOI: 10.1016/j.mvr.2022.104403] [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: 12/22/2021] [Revised: 05/23/2022] [Accepted: 06/20/2022] [Indexed: 11/19/2022]
Abstract
Blood-labyrinth barrier (BLB) disruption plays a crucial role in the development of otitis media. The aims of our study was to explore the role and action mechanism of adenosine in LPS-induced endothelial cells (ECs) damage, which are one of the major principal cell type for blood-labyrinth barrier (BLB), and so as to assess the potential of adenosine to be used in the treatment of BLB disruption in animal experiment. In our study, ECs were treated with LPS to mimic BLB damage in vitro. Our data showed that adenosine at dosage of 1, 10, and 20 μM had no influence on the cell viability of ECs. LPS treatment obviously suppressed the expression of Occludin and Zonula occludens-1 (ZO-1) in ECs, which was partly recused by adenosine treatment. Meantime, LPS-induced increasing in reactive oxygen species (ROS) production and ECs permeability also was rescued by adenosine treatment. However, inhibition the A2A receptor (A2AR) could attenuate the influence of adenosine on LPS-treated ECs, indicating that adenosine alleviated LPS-induced BLB damage by activating A2AR. Moreover, the inhibition of adenosine to LPS-induced inactivation of AMPK/AKT signaling pathway was partly recused by A2AR suppression. In addition, Compound C (an AMPK inhibitor) decreased the expression of Occludin and ZO-1 in ECs following LPS combined with adenosine treatment. In conclusion, adenosine alleviates LPS-induced BLB damage via AMPK/AKT pathway through activation of A2AR. This work suggests that adenosine may be a candidate drug for the treatment of BLB dysfunction-related diseases.
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Affiliation(s)
- Jinhui Zhang
- Department of otorhinolaryngology, Head and Neck surgery, The First Affiliated Hospital of Zhengzhou University, No 1 Jianshe Road, Zhengzhou 450052, Henan, China.
| | - Wenya Fan
- Department of otorhinolaryngology, Head and Neck surgery, The First Affiliated Hospital of Zhengzhou University, No 1 Jianshe Road, Zhengzhou 450052, Henan, China
| | - Lingling Neng
- Department of otorhinolaryngology, Head and Neck surgery, The First Affiliated Hospital of Zhengzhou University, No 1 Jianshe Road, Zhengzhou 450052, Henan, China
| | - Bei Chen
- Department of otorhinolaryngology, Head and Neck surgery, The First Affiliated Hospital of Zhengzhou University, No 1 Jianshe Road, Zhengzhou 450052, Henan, China
| | - Yanting Wang
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, No 16, Jiangsu Road, Qingdao, Shandong, China
| | - Bin Zuo
- Department of otorhinolaryngology, Head and Neck surgery, The First Affiliated Hospital of Zhengzhou University, No 1 Jianshe Road, Zhengzhou 450052, Henan, China
| | - Wei Lu
- Department of otorhinolaryngology, Head and Neck surgery, The First Affiliated Hospital of Zhengzhou University, No 1 Jianshe Road, Zhengzhou 450052, Henan, China.
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Oike H, Tomita S, Koyano H, Azami K. Garland chrysanthemum consumption ameliorates age-related hearing loss in C57BL/6 mouse; model system to explore hearing loss prevention foods in a short period. Biosci Biotechnol Biochem 2022; 86:1085-1094. [PMID: 35687003 DOI: 10.1093/bbb/zbac092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/30/2022] [Indexed: 11/13/2022]
Abstract
Garland chrysanthemum (Glebionis coronaria L.) is an antioxidant-rich leafy vegetable. We found that garland chrysanthemum consumption ameliorated age-related hearing loss (AHL) in C57BL/6J mice, an early onset model. We also found that AHL progression was significantly ameliorated by three of ten products. Metabolome analysis of the 10 products using nuclear magnetic resonance (NMR) spectroscopy indicated that phytosterols may be involved in the amelioration of AHL. However, the direct inhibitory effect of phytosterol mixture on mouse AHL progression was not identified. These results suggest that garland chrysanthemum consumption delays AHL development in mice and its efficiency varies depending on the source of product. Our findings also suggest that phytosterol content in garland chrysanthemum function as an evaluation marker for the efficiency. Furthermore, to accelerate the search for foods that prevent AHL, we have used these data to develop an automatic threshold determination method for auditory brainstem response using machine learning.
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Affiliation(s)
- Hideaki Oike
- Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.,Research Center for Agricultural Information Technology, National Agriculture and Food Research Organization (NARO), 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8517, Japan
| | - Satoru Tomita
- Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
| | - Hitoshi Koyano
- Research Center for Agricultural Information Technology, National Agriculture and Food Research Organization (NARO), 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8517, Japan
| | - Kayo Azami
- Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
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9
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Oike H, Kohyama K, Mochizuki-Kawai H, Azami K. Food hardness influences the progression of age-related hearing loss in mice. Exp Gerontol 2021; 149:111335. [PMID: 33785396 DOI: 10.1016/j.exger.2021.111335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/05/2021] [Accepted: 03/24/2021] [Indexed: 12/20/2022]
Abstract
C57BL/6J and DBA/2J mice are often used for hearing research because of their early onset and progression of age-related hearing loss (AHL). Here, we report that the hardness of the diet affects the progression of AHL in these mice. When C57BL/6J mice and DBA/2J mice were fed a pellet-type or powder-type standard AIN93M diet, the pellet diet significantly promoted AHL. AHL promotion was eliminated by crushing the pellet diet to a powder. Subsequently, when C57BL/6J mice were fed the pellet-type AIN93M diet obtained from three different manufacturers, two of them significantly promoted AHL. The hardness of the diets was measured, and it was found that the two diets that promoted AHL were significantly harder than the other diet. Next, we attempted to reduce diet hardness by replacing some nutritional ingredients with dried eggs or phosphatidylcholine (PC), and we succeeded in obtaining brittle diets with lower hardness values. Then, C57BL/6J mice were bred with brittle diets for 6 months and the promotion of AHL was suppressed to the equivalent level as the powder diet. Furthermore, when senescence-accelerated mice, SAMP8, were fed a brittle diet for one year, the progression of AHL was also suppressed; however, it did not affect other aging indexes, such as mental and physical performance. We also confirmed that a high-fat pellet diet, which is soft even in pellet form, did not promote AHL. Time-restricted feeding (tRF), which is a chrono-nutritional method to delay aging, ameliorated the promotion of AHL by the hard AIN93M pellets in C57BL/6J mice. These results indicate that the physical form and hardness of diets affect the progression of AHL in mouse models.
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Affiliation(s)
- Hideaki Oike
- Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan; Research Center for Agricultural Information Technology, National Agriculture and Food Research Organization (NARO), 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8517, Japan.
| | - Kaoru Kohyama
- Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
| | - Hiroko Mochizuki-Kawai
- Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
| | - Kayo Azami
- Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
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10
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Fok C, Bogosanovic M, Pandya M, Telang R, Thorne PR, Vlajkovic SM. Regulator of G Protein Signalling 4 (RGS4) as a Novel Target for the Treatment of Sensorineural Hearing Loss. Int J Mol Sci 2020; 22:ijms22010003. [PMID: 33374915 PMCID: PMC7792627 DOI: 10.3390/ijms22010003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/16/2020] [Accepted: 12/19/2020] [Indexed: 12/20/2022] Open
Abstract
We and others have previously identified signalling pathways associated with the adenosine A1 receptor (A1R) as important regulators of cellular responses to injury in the cochlea. We have shown that the “post-exposure” treatment with adenosine A1R agonists confers partial protection against acoustic trauma and other forms of sensorineural hearing loss (SNHL). The aim of this study was to determine if increasing A1R responsiveness to endogenous adenosine would have the same otoprotective effect. This was achieved by pharmacological targeting of the Regulator of G protein Signalling 4 (RGS4). RGS proteins inhibit signal transduction pathways initiated by G protein-coupled receptors (GPCR) by enhancing GPCR deactivation and receptor desensitisation. A molecular complex between RGS4 and neurabin, an intracellular scaffolding protein expressed in neural and cochlear tissues, is the key negative regulator of A1R activity in the brain. In this study, Wistar rats (6–8 weeks) were exposed to traumatic noise (110 dBSPL, 8–16 kHz) for 2 h and a small molecule RGS4 inhibitor CCG-4986 was delivered intratympanically in a Poloxamer-407 gel formulation for sustained drug release 24 or 48 h after noise exposure. Intratympanic administration of CCG-4986 48 h after noise exposure attenuated noise-induced permanent auditory threshold shifts by up to 19 dB, whilst the earlier drug administration (24 h) led to even better preservation of auditory thresholds (up to 32 dB). Significant improvement of auditory thresholds and suprathreshold responses was linked to improved survival of sensorineural tissues and afferent synapses in the cochlea. Our studies thus demonstrate that intratympanic administration of CCG-4986 can rescue cochlear injury and hearing loss induced by acoustic overexposure. This research represents a novel paradigm for the treatment of various forms of SNHL based on regulation of GPCR.
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Kawashima T, Harai K, Fujita N, Takahashi R. Ninjinyoeito Has a Protective Effect on the Auditory Nerve and Suppresses the Progression of Age-Related Hearing Loss in Mice. Front Nutr 2020; 7:528864. [PMID: 33163504 PMCID: PMC7583632 DOI: 10.3389/fnut.2020.528864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 09/01/2020] [Indexed: 12/02/2022] Open
Abstract
Currently, there are limited reports available regarding the treatment and prevention of progressive age-related hearing loss. This is because age-related hearing loss is not a critical disease with direct fatalities and has several well-established countermeasures such as hearing aids and cochlear implants. This study evaluated the efficacy of Ninjinyoeito (NYT) in the treatment of age-related hearing loss. C57BL/6J mice were divided into three groups: baseline group, untreated group, and NYT-treated group, with the latter receiving NYT treatment for 2 months. The mice were fed with NYT extract mixed with 4% mouse normal chow. Hearing loss was confirmed by a reduction in intact cell density of the auditory nerve from the age of 5–7 months. The suppression of hearing loss with aging and decrease in the intact cell density of the auditory nerve were significant in mice fed with NYT for 2 months. NYT has been reported to improve blood flow and enhance mitochondrial activity and may exert its protective effects on spiral neurons through these mechanisms. There was no decrease in the size of the stria vascularis from the age of 5–7 months in C57BL/6J mice. The present model failed to reveal the effect of NYT on atrophy of the stria vascularis of the cochlear duct. In conclusion, NYT appears to have a protective effect on the auditory nerve and suppress the progression of age-related hearing loss by reducing age-related auditory nerve degeneration.
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Affiliation(s)
| | - Kenji Harai
- Kampo Research Laboratories, Kracie Pharma, Ltd., Tokyo, Japan
| | - Nina Fujita
- Kampo Research Laboratories, Kracie Pharma, Ltd., Tokyo, Japan
| | - Ryuji Takahashi
- Kampo Research Laboratories, Kracie Pharma, Ltd., Tokyo, Japan
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12
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Bielefeld EC, Kobel MJ. Advances and Challenges in Pharmaceutical Therapies to Prevent and Repair Cochlear Injuries From Noise. Front Cell Neurosci 2019; 13:285. [PMID: 31297051 PMCID: PMC6607696 DOI: 10.3389/fncel.2019.00285] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/13/2019] [Indexed: 12/20/2022] Open
Abstract
Noise induces a broad spectrum of pathological injuries to the cochlea, reflecting both mechanical damage to the delicate architecture of the structures of the organ of Corti and metabolic damage within the organ of Corti and lateral wall tissues. Unlike ototoxic medications, the blood-labyrinth barrier does not offer protection against noise injury. The blood-labyrinth barrier is a target of noise injury, and can be weakened as part of the metabolic pathologies in the cochlea. However, it also offers a potential for therapeutic intervention with oto-protective compounds. Because the blood-labyrinth barrier is weakened by noise, penetration of blood-borne oto-protective compounds could be higher. However, systemic dosing for cochlear protection from noise offers other significant challenges. An alternative option to systemic dosing is local administration to the cochlea through the round window membrane using a variety of drug delivery techniques. The review will discuss noise-induced cochlear pathology, including alterations to the blood-labyrinth barrier, and then transition into discussing approaches for delivery of oto-protective compounds to reduce cochlear injury from noise.
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Affiliation(s)
- Eric C Bielefeld
- Department of Speech and Hearing Science, The Ohio State University, Columbus, OH, United States
| | - Megan J Kobel
- Department of Speech and Hearing Science, The Ohio State University, Columbus, OH, United States.,Department of Otolaryngology-Head & Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, United States
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13
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Zhang Y, Guo L, Lu X, Cheng C, Sun S, Li W, Zhao L, Lai C, Zhang S, Yu C, Tang M, Chen Y, Chai R, Li H. Characterization of Lgr6+ Cells as an Enriched Population of Hair Cell Progenitors Compared to Lgr5+ Cells for Hair Cell Generation in the Neonatal Mouse Cochlea. Front Mol Neurosci 2018; 11:147. [PMID: 29867341 PMCID: PMC5961437 DOI: 10.3389/fnmol.2018.00147] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/12/2018] [Indexed: 12/20/2022] Open
Abstract
Hair cell (HC) loss is irreversible because only very limited HC regeneration has been observed in the adult mammalian cochlea. Wnt/β-catenin signaling regulates prosensory cell proliferation and differentiation during cochlear development, and Wnt activation promotes the proliferation of Lgr5+ cochlear HC progenitors in newborn mice. Similar to Lgr5, Lgr6 is also a Wnt downstream target gene. Lgr6 is reported to be present in adult stem cells in the skin, nail, tongue, lung, and mammary gland, and this protein is very important for adult stem cell maintenance in rapidly proliferating organs. Our previous studies showed that Lgr6+ cells are a subpopulation of Lgr5+ progenitor cells and that both Lgr6+ and Lgr5+ progenitors can generate Myosin7a+ HCs in vitro. Thus we hypothesized that Lgr6+ cells are an enriched population of cochlear progenitor cells. However, the detailed distinctions between the Lgr5+ and Lgr6+ progenitors are unclear. Here, we systematically compared the proliferation, HC differentiation, and detailed transcriptome expression profiles of these two progenitor populations. We found that the same number of isolated Lgr6+ progenitors generated significantly more Myosin7a+ HCs compared to Lgr5+ progenitors; however, Lgr5+ progenitors formed more epithelial colonies and more spheres than Lgr6+ progenitors in vitro. Using RNA-Seq, we compared the transcriptome differences between Lgr5+ and Lgr6+ progenitors and identified a list of significantly differential expressed genes that might regulate the proliferation and differentiation of these HC progenitors, including 4 cell cycle genes, 9 cell signaling pathway genes, and 54 transcription factors. In conclusion, we demonstrate that Lgr6+ progenitors are an enriched population of inner ear progenitors that generate more HCs compared to Lgr5+ progenitors in the newborn mouse cochlea, and the our research provides a series of genes that might regulate the proliferation of progenitors and HC generation.
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Affiliation(s)
- Yanping Zhang
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Xiaoling Lu
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Cheng Cheng
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Shan Sun
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Wen Li
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Liping Zhao
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Chuijin Lai
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Chenjie Yu
- Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline Laboratory, Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Yan Chen
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.,Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine, National Health and Family Planning Commission (NHFPC), Shanghai, China.,Shanghai Engineering Research Center of Cochlear Implant, Shanghai, China.,The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China
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14
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Kalinec GM, Lomberk G, Urrutia RA, Kalinec F. Resolution of Cochlear Inflammation: Novel Target for Preventing or Ameliorating Drug-, Noise- and Age-related Hearing Loss. Front Cell Neurosci 2017; 11:192. [PMID: 28736517 PMCID: PMC5500902 DOI: 10.3389/fncel.2017.00192] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 06/20/2017] [Indexed: 12/11/2022] Open
Abstract
A significant number of studies support the idea that inflammatory responses are intimately associated with drug-, noise- and age-related hearing loss (DRHL, NRHL and ARHL). Consequently, several clinical strategies aimed at reducing auditory dysfunction by preventing inflammation are currently under intense scrutiny. Inflammation, however, is a normal adaptive response aimed at restoring tissue functionality and homeostasis after infection, tissue injury and even stress under sterile conditions, and suppressing it could have unintended negative consequences. Therefore, an appropriate approach to prevent or ameliorate DRHL, NRHL and ARHL should involve improving the resolution of the inflammatory process in the cochlea rather than inhibiting this phenomenon. The resolution of inflammation is not a passive response but rather an active, highly controlled and coordinated process. Inflammation by itself produces specialized pro-resolving mediators with critical functions, including essential fatty acid derivatives (lipoxins, resolvins, protectins and maresins), proteins and peptides such as annexin A1 and galectins, purines (adenosine), gaseous mediators (NO, H2S and CO), as well as neuromodulators like acetylcholine and netrin-1. In this review article, we describe recent advances in the understanding of the resolution phase of inflammation and highlight therapeutic strategies that might be useful in preventing inflammation-induced cochlear damage. In particular, we emphasize beneficial approaches that have been tested in pre-clinical models of inflammatory responses induced by recognized ototoxic drugs such as cisplatin and aminoglycoside antibiotics. Since these studies suggest that improving the resolution process could be useful for the prevention of inflammation-associated diseases in humans, we discuss the potential application of similar strategies to prevent or mitigate DRHL, NRHL and ARHL.
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Affiliation(s)
- Gilda M Kalinec
- Laboratory of Auditory Cell Biology, Department of Head and Neck Surgery, David Geffen School of Medicine, University of CaliforniaLos Angeles, Los Angeles, CA, United States
| | - Gwen Lomberk
- Epigenetics and Chromatin Dynamics Laboratory, Translational Epigenomic Program, Center for Individualized Medicine (CIM) Mayo ClinicRochester, MN, United States
| | - Raul A Urrutia
- Epigenetics and Chromatin Dynamics Laboratory, Translational Epigenomic Program, Center for Individualized Medicine (CIM) Mayo ClinicRochester, MN, United States
| | - Federico Kalinec
- Laboratory of Auditory Cell Biology, Department of Head and Neck Surgery, David Geffen School of Medicine, University of CaliforniaLos Angeles, Los Angeles, CA, United States
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15
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Oike H. Intake of Egg Prevents Age-related Hearing Loss in Mice. J JPN SOC FOOD SCI 2017. [DOI: 10.3136/nskkk.64.104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Hideaki Oike
- Food Research Institute, National Agriculture and Food Research Organization (NARO)
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16
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Vlajkovic SM, Ambepitiya K, Barclay M, Boison D, Housley GD, Thorne PR. Adenosine receptors regulate susceptibility to noise-induced neural injury in the mouse cochlea and hearing loss. Hear Res 2016; 345:43-51. [PMID: 28034618 DOI: 10.1016/j.heares.2016.12.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/15/2016] [Accepted: 12/20/2016] [Indexed: 12/20/2022]
Abstract
Our previous studies have shown that the stimulation of A1 adenosine receptors in the inner ear can mitigate the loss of sensory hair cells and hearing loss caused by exposure to traumatic noise. Here, we focus on the role of adenosine receptors (AR) in the development of noise-induced neural injury in the cochlea using A1AR and A2AAR null mice (A1AR-/- and A2AAR-/-). Wildtype (WT) and AR deficient mice were exposed to octave band noise (8-16 kHz, 100 dB SPL) for 2 h to induce cochlear injury and hearing loss. Auditory thresholds and input/output functions were assessed using auditory brainstem responses (ABR) before and two weeks post-exposure. The loss of outer hair cells (OHC), afferent synapses and spiral ganglion neurons (SGN) were assessed by quantitative histology. A1AR-/- mice (6-8 weeks old) displayed a high frequency hearing loss (ABR threshold shift and reduced ABR wave I and II amplitudes). This hearing loss was further aggravated by acute noise exposure and exceeded the hearing loss in the WT and A2AAR-/- mice. All mice experienced the loss of OHC, synaptic ribbons and SGN after noise exposure, but the loss of SGN was significantly higher in A1AR-/- mice than in the A2AAR-/- and WT genotypes. The A2AAR-/- demonstrated better preservation of OHC and afferent synapses and the minimal loss of SGN after noise exposure. The findings suggest that the loss of A1AR expression results in an increased susceptibility to cochlear neural injury and hearing loss, whilst absence of A2AAR increases cochlear resistance to acoustic trauma.
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Affiliation(s)
- Srdjan M Vlajkovic
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, 92019, Auckland, New Zealand; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, 92019, Auckland, New Zealand.
| | - Kaushi Ambepitiya
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, 92019, Auckland, New Zealand; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, 92019, Auckland, New Zealand
| | - Meagan Barclay
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, 92019, Auckland, New Zealand; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, 92019, Auckland, New Zealand
| | - Detlev Boison
- RS Dow Neurobiology Laboratories, Legacy Research, Portland, OR, 97232, USA
| | - Gary D Housley
- Department of Physiology and Translational Neuroscience Facility, School of Medical Sciences, UNSW Australia, Sydney, NSW, 2052, Australia
| | - Peter R Thorne
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, 92019, Auckland, New Zealand; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, 92019, Auckland, New Zealand
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17
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Kaur T, Borse V, Sheth S, Sheehan K, Ghosh S, Tupal S, Jajoo S, Mukherjea D, Rybak LP, Ramkumar V. Adenosine A1 Receptor Protects Against Cisplatin Ototoxicity by Suppressing the NOX3/STAT1 Inflammatory Pathway in the Cochlea. J Neurosci 2016; 36:3962-77. [PMID: 27053204 PMCID: PMC4821909 DOI: 10.1523/jneurosci.3111-15.2016] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 02/16/2016] [Accepted: 02/26/2016] [Indexed: 01/19/2023] Open
Abstract
Cisplatin is a commonly used antineoplastic agent that produces ototoxicity that is mediated in part by increasing levels of reactive oxygen species (ROS) via the NOX3 NADPH oxidase pathway in the cochlea. Recent studies implicate ROS generation in mediating inflammatory and apoptotic processes and hearing loss by activating signal transducer and activator of transcription (STAT1). In this study, we show that the adenosine A1 receptor (A1AR) protects against cisplatin ototoxicity by suppressing an inflammatory response initiated by ROS generation via NOX3 NADPH oxidase, leading to inhibition of STAT1. Trans-tympanic administration of the A1AR agonist R-phenylisopropyladenosine (R-PIA) inhibited cisplatin-induced ototoxicity, as measured by auditory brainstem responses and scanning electron microscopy in male Wistar rats. This was associated with reduced NOX3 expression, STAT1 activation, tumor necrosis factor-α (TNF-α) levels, and apoptosis in the cochlea. In vitro studies in UB/OC-1 cells, an organ of Corti immortalized cell line, showed that R-PIA reduced cisplatin-induced phosphorylation of STAT1 Ser(727) (but not Tyr(701)) and STAT1 luciferase activity by suppressing the ERK1/2, p38, and JNK mitogen-activated protein kinase (MAPK) pathways.R-PIA also decreased the expression of STAT1 target genes, such as TNF-α, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and reduced cisplatin-mediated apoptosis. These data suggest that the A1AR provides otoprotection by suppressing NOX3 and inflammation in the cochlea and could serve as an ideal target for otoprotective drug therapy. SIGNIFICANCE STATEMENT Cisplatin is a widely used chemotherapeutic agent for the treatment of solid tumors. Its use results in significant and permanent hearing loss, for which no US Food and Drug Administration-approved treatment is currently available. In this study, we targeted the cochlear adenosine A1 receptor (A1AR) by trans-tympanic injections of the agonist R-phenylisopropyladenosine (R-PIA) and showed that it reduced cisplatin-induced inflammation and apoptosis in the rat cochlea and preserved hearing. The mechanism of protection involves suppression of the NOX3 NADPH oxidase enzyme, a major target of cisplatin-induced reactive oxygen species (ROS) generation in the cochlea. ROS initiates an inflammatory and apoptotic cascade in the cochlea by activating STAT1 transcription factor, which is attenuated byR-PIA. Therefore, trans-tympanic delivery of A1AR agonists could effectively treat cisplatin ototoxicity.
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Affiliation(s)
- Tejbeer Kaur
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri 63110, and
| | | | | | - Kelly Sheehan
- Department of Surgery, Southern Illinois University School of Medicine, Springfield, Illinois 62794
| | | | | | | | - Debashree Mukherjea
- Department of Surgery, Southern Illinois University School of Medicine, Springfield, Illinois 62794
| | - Leonard P Rybak
- Department of Pharmacology and Department of Surgery, Southern Illinois University School of Medicine, Springfield, Illinois 62794
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18
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Oike H, Aoki-Yoshida A, Kimoto-Nira H, Yamagishi N, Tomita S, Sekiyama Y, Wakagi M, Sakurai M, Ippoushi K, Suzuki C, Kobori M. Dietary intake of heat-killed Lactococcus lactis H61 delays age-related hearing loss in C57BL/6J mice. Sci Rep 2016; 6:23556. [PMID: 27000949 PMCID: PMC4802309 DOI: 10.1038/srep23556] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/09/2016] [Indexed: 12/20/2022] Open
Abstract
Age-related hearing loss (AHL) is a common disorder associated with aging. In this study, we investigated the effect of the intake of heat-killed Lactococcus lactis subsp. cremoris H61 (strain H61) on AHL in C57BL/6J mice. Measurement of the auditory brainstem response (ABR) demonstrated that female mice at 9 months of age fed a diet containing 0.05% strain H61 for 6 months maintained a significantly lower ABR threshold than control mice. The age-related loss of neurons and hair cells in the cochlea was suppressed by the intake of strain H61. Faecal analysis of bacterial flora revealed that the intake of strain H61 increased the prevalence of Lactobacillales, which is positively correlated with hearing ability in mice. Furthermore, plasma fatty acid levels were negatively correlated with hearing ability. Overall, the results supported that the intake of heat-killed strain H61 for 6 months altered the intestinal flora, affected plasma metabolite levels, including fatty acid levels, and retarded AHL in mice.
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Affiliation(s)
- Hideaki Oike
- National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, JAPAN
| | - Ayako Aoki-Yoshida
- NARO Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, 2 Ikenodai, Tsukuba, Ibaraki 305-0901, JAPAN.,Graduate school of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, JAPAN
| | - Hiromi Kimoto-Nira
- NARO Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, 2 Ikenodai, Tsukuba, Ibaraki 305-0901, JAPAN
| | - Naoko Yamagishi
- NARO Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, 2 Ikenodai, Tsukuba, Ibaraki 305-0901, JAPAN
| | - Satoru Tomita
- National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, JAPAN
| | - Yasuyo Sekiyama
- National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, JAPAN
| | - Manabu Wakagi
- National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, JAPAN
| | - Mutsumi Sakurai
- National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, JAPAN
| | - Katsunari Ippoushi
- National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, JAPAN
| | - Chise Suzuki
- NARO Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, 2 Ikenodai, Tsukuba, Ibaraki 305-0901, JAPAN
| | - Masuko Kobori
- National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, JAPAN
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19
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Barclay M, Constable R, James NR, Thorne PR, Montgomery JM. Reduced sensory stimulation alters the molecular make-up of glutamatergic hair cell synapses in the developing cochlea. Neuroscience 2016; 325:50-62. [PMID: 27012610 DOI: 10.1016/j.neuroscience.2016.03.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 02/26/2016] [Accepted: 03/16/2016] [Indexed: 12/20/2022]
Abstract
Neural activity during early development is known to alter innervation pathways in the central and peripheral nervous systems. We sought to examine how reduced sound-induced sensory activity in the cochlea affected the consolidation of glutamatergic synapses between inner hair cells (IHC) and the primary auditory neurons as these synapses play a primary role in transmitting sound information to the brain. A unilateral conductive hearing loss was induced prior to the onset of sound-mediated stimulation of the sensory hair cells, by rupturing the tympanic membrane and dislocating the auditory ossicles in the left ear of P11 mice. Auditory brainstem responses at P15 and P21 showed a 40-50-dB increase in thresholds for frequencies 8-32kHz in the dislocated ear relative to the control ear. Immunohistochemistry and confocal microscopy were subsequently used to examine the effect of this attenuation of sound stimulation on the expression of RIBEYE, which comprises the presynaptic ribbons, Shank-1, a postsynaptic scaffolding protein, and the GluA2/3 and 4 subunits of postsynaptic AMPA receptors. Our results show that dislocation did not alter the number of pre- or postsynaptic protein puncta. However, dislocation did increase the size of RIBEYE, GluA4, GluA2/3 and Shank-1 puncta, with postsynaptic changes preceding presynaptic changes. Our data suggest that a reduction in sound stimulation during auditory development induces plasticity in the molecular make-up of IHC glutamatergic synapses, but does not affect the number of these synapses. Up-regulation of synaptic proteins with sound attenuation may facilitate a compensatory increase in synaptic transmission due to the reduced sensory stimulation of the IHC.
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Affiliation(s)
- M Barclay
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - R Constable
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - N R James
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - P R Thorne
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Section of Audiology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - J M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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20
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Wong ACY, Ryan AF. Mechanisms of sensorineural cell damage, death and survival in the cochlea. Front Aging Neurosci 2015; 7:58. [PMID: 25954196 PMCID: PMC4404918 DOI: 10.3389/fnagi.2015.00058] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/05/2015] [Indexed: 12/20/2022] Open
Abstract
The majority of acquired hearing loss, including presbycusis, is caused by irreversible damage to the sensorineural tissues of the cochlea. This article reviews the intracellular mechanisms that contribute to sensorineural damage in the cochlea, as well as the survival signaling pathways that can provide endogenous protection and tissue rescue. These data have primarily been generated in hearing loss not directly related to age. However, there is evidence that similar mechanisms operate in presbycusis. Moreover, accumulation of damage from other causes can contribute to age-related hearing loss (ARHL). Potential therapeutic interventions to balance opposing but interconnected cell damage and survival pathways, such as antioxidants, anti-apoptotics, and pro-inflammatory cytokine inhibitors, are also discussed.
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Affiliation(s)
- Ann C Y Wong
- Department of Surgery/Division of Otolaryngology, University of California, San Diego School of Medicine La Jolla, CA, USA ; Department of Physiology and Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales Sydney, NSW, Australia
| | - Allen F Ryan
- Department of Surgery/Division of Otolaryngology, University of California, San Diego School of Medicine La Jolla, CA, USA ; Veterans Administration Medical Center La Jolla, CA, USA ; Department of Neurosciences, University of California, San Diego School of Medicine La Jolla, CA, USA
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21
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Martínez-Vega R, Garrido F, Partearroyo T, Cediel R, Zeisel SH, Martínez-Álvarez C, Varela-Moreiras G, Varela-Nieto I, Pajares MA. Folic acid deficiency induces premature hearing loss through mechanisms involving cochlear oxidative stress and impairment of homocysteine metabolism. FASEB J 2014; 29:418-32. [PMID: 25384423 DOI: 10.1096/fj.14-259283] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nutritional imbalance is emerging as a causative factor of hearing loss. Epidemiologic studies have linked hearing loss to elevated plasma total homocysteine (tHcy) and folate deficiency, and have shown that folate supplementation lowers tHcy levels potentially ameliorating age-related hearing loss. The purpose of this study was to address the impact of folate deficiency on hearing loss and to examine the underlying mechanisms. For this purpose, 2-mo-old C57BL/6J mice (Animalia Chordata Mus musculus) were randomly divided into 2 groups (n = 65 each) that were fed folate-deficient (FD) or standard diets for 8 wk. HPLC analysis demonstrated a 7-fold decline in serum folate and a 3-fold increase in tHcy levels. FD mice exhibited severe hearing loss measured by auditory brainstem recordings and TUNEL-positive-apoptotic cochlear cells. RT-quantitative PCR and Western blotting showed reduced levels of enzymes catalyzing homocysteine (Hcy) production and recycling, together with a 30% increase in protein homocysteinylation. Redox stress was demonstrated by decreased expression of catalase, glutathione peroxidase 4, and glutathione synthetase genes, increased levels of manganese superoxide dismutase, and NADPH oxidase-complex adaptor cytochrome b-245, α-polypeptide (p22phox) proteins, and elevated concentrations of glutathione species. Altogether, our findings demonstrate, for the first time, that the relationship between hyperhomocysteinemia induced by folate deficiency and premature hearing loss involves impairment of cochlear Hcy metabolism and associated oxidative stress.
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Affiliation(s)
- Raquel Martínez-Vega
- *Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Unidad 761, Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU San Pablo, Boadilla del Monte, Madrid, Spain; Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain; University of North Carolina at Chapel Hill, Nutrition Research Institute, Kannapolis, North Carolina, USA; Departamento de Anatomía y Embriología Humana I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria La Paz, Madrid, Spain
| | - Francisco Garrido
- *Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Unidad 761, Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU San Pablo, Boadilla del Monte, Madrid, Spain; Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain; University of North Carolina at Chapel Hill, Nutrition Research Institute, Kannapolis, North Carolina, USA; Departamento de Anatomía y Embriología Humana I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria La Paz, Madrid, Spain
| | - Teresa Partearroyo
- *Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Unidad 761, Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU San Pablo, Boadilla del Monte, Madrid, Spain; Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain; University of North Carolina at Chapel Hill, Nutrition Research Institute, Kannapolis, North Carolina, USA; Departamento de Anatomía y Embriología Humana I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria La Paz, Madrid, Spain
| | - Rafael Cediel
- *Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Unidad 761, Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU San Pablo, Boadilla del Monte, Madrid, Spain; Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain; University of North Carolina at Chapel Hill, Nutrition Research Institute, Kannapolis, North Carolina, USA; Departamento de Anatomía y Embriología Humana I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria La Paz, Madrid, Spain
| | - Steven H Zeisel
- *Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Unidad 761, Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU San Pablo, Boadilla del Monte, Madrid, Spain; Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain; University of North Carolina at Chapel Hill, Nutrition Research Institute, Kannapolis, North Carolina, USA; Departamento de Anatomía y Embriología Humana I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria La Paz, Madrid, Spain
| | - Concepción Martínez-Álvarez
- *Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Unidad 761, Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU San Pablo, Boadilla del Monte, Madrid, Spain; Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain; University of North Carolina at Chapel Hill, Nutrition Research Institute, Kannapolis, North Carolina, USA; Departamento de Anatomía y Embriología Humana I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria La Paz, Madrid, Spain
| | - Gregorio Varela-Moreiras
- *Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Unidad 761, Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU San Pablo, Boadilla del Monte, Madrid, Spain; Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain; University of North Carolina at Chapel Hill, Nutrition Research Institute, Kannapolis, North Carolina, USA; Departamento de Anatomía y Embriología Humana I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria La Paz, Madrid, Spain
| | - Isabel Varela-Nieto
- *Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Unidad 761, Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU San Pablo, Boadilla del Monte, Madrid, Spain; Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain; University of North Carolina at Chapel Hill, Nutrition Research Institute, Kannapolis, North Carolina, USA; Departamento de Anatomía y Embriología Humana I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria La Paz, Madrid, Spain
| | - María A Pajares
- *Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Unidad 761, Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU San Pablo, Boadilla del Monte, Madrid, Spain; Hospital Clínico Veterinario, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain; University of North Carolina at Chapel Hill, Nutrition Research Institute, Kannapolis, North Carolina, USA; Departamento de Anatomía y Embriología Humana I, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria La Paz, Madrid, Spain
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Ahmad S, Elsherbiny NM, Bhatia K, Elsherbini AM, Fulzele S, Liou GI. Inhibition of adenosine kinase attenuates inflammation and neurotoxicity in traumatic optic neuropathy. J Neuroimmunol 2014; 277:96-104. [PMID: 25457840 DOI: 10.1016/j.jneuroim.2014.10.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 10/03/2014] [Accepted: 10/15/2014] [Indexed: 12/20/2022]
Abstract
Traumatic optic neuropathy (TON) is associated with apoptosis of retinal ganglion cells. Local productions of reactive oxygen species and inflammatory mediators from activated microglial cells have been hypothesized to underlie apoptotic processes. We previously demonstrated that the anti-inflammatory effect of adenosine, through A2A receptor activation had profound protective influence against retinal injury in traumatic optic neuropathy. This protective effect is limited due to rapid cellular re-uptake of adenosine by equilibrative nucleotside transporter-1 (ENT1) or break down by adenosine kinase (AK), the key enzyme in adenosine clearance pathway. Further, the use of adenosine receptors agonists are limited by systemic side effects. Therefore, we seek to investigate the potential role of amplifying the endogenous ambient level of adenosine by pharmacological inhibition of AK. We tested our hypothesis by comparing TON-induced retinal injury in mice with and without ABT-702 treatment, a selective AK inhibitor (AKI). The retinal-protective effect of ABT-702 was demonstrated by significant reduction of Iba-1, ENT1, TNF-α, IL-6, and iNOS/nNOS protein or mRNA expression in TON as revealed by western blot and real time PCR. TON-induced superoxide anion generation and nitrotyrosine expression were reduced in ABT-702 treated mice retinal sections as determined by immunoflourescence. In addition, ABT-702 attenuated p-ERK1/2 and p-P38 activation in LPS induced activated mouse microglia cells. The results of the present investigation suggested that ABT-702 had a protective role against marked TON-induced retinal inflammation and damage by augmenting the endogenous therapeutic effects of site- and event-specific accumulation of extracellular adenosine.
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Affiliation(s)
- Saif Ahmad
- Department of Ophthalmology, School of Medicine, Georgia Regents University (GRU), Augusta, GA, USA; Departmet of Biological Sciences, Rabigh College of Science and Arts, King Abdulaziz University, Rabigh, Saudi Arabia.
| | - Nehal M Elsherbiny
- Department of Ophthalmology, School of Medicine, Georgia Regents University (GRU), Augusta, GA, USA; Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - Kanchan Bhatia
- Departmet of Biological Sciences, Rabigh College of Science and Arts, King Abdulaziz University, Rabigh, Saudi Arabia
| | - Ahmed M Elsherbini
- Department of Ophthalmology, School of Medicine, Georgia Regents University (GRU), Augusta, GA, USA
| | - Sadanand Fulzele
- Department of Orthopedics, Georgia Regents University (GRU), Augusta, GA, USA
| | - Gregory I Liou
- Department of Ophthalmology, School of Medicine, Georgia Regents University (GRU), Augusta, GA, USA.
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23
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Tan WJT, Thorne PR, Vlajkovic SM. Noise-induced cochlear inflammation. World J Otorhinolaryngol 2013; 3:89-99. [DOI: 10.5319/wjo.v3.i3.89] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/08/2013] [Accepted: 08/20/2013] [Indexed: 02/06/2023] Open
Abstract
Hearing loss is the most common sensory disability with considerable social and economic implications. According to recent World Health Organization estimates, 360 million people worldwide suffer from moderate to profound hearing loss. Exposure to excessive noise is one of the major causes of sensorineural hearing loss, secondary only to age-related hearing loss (presbyacusis). Since cochlear tissues have limited abilities of repair and regeneration, this damage can be irreversible, leading to cochlear dysfunction and permanent hearing loss. Recent studies have shown that cochlear inflammation can be induced by noise exposure and contribute to the overall pathogenesis of cochlear injury and hearing loss. The cochlea is separated from the systemic circulation by the blood-labyrinth barrier, which is physiologically similar to the blood-brain barrier of the central nervous system. Because of this feature, the cochlea was originally considered an immunologically privileged organ. However, this postulate has been challenged by the evidence of an inflammatory response in the cochlea in the presence of bacterial or viral pathogens or antigens that can cause labyrinthitis. Although the main purpose of the inflammatory reaction is to protect against invading pathogens, the inflammatory response can also cause significant bystander injury to the delicate structures of the cochlea. The cochlear inflammatory response is characterised by the generation of proinflammatory mediators (cytokines, chemokines and adhesion molecules), and the recruitment of inflammatory cells (leukocytes). Here, we present an overview of the current research on cochlear inflammation, with particular emphasis on noise-induced cochlear inflammation. We also discuss treatment strategies aimed at the suppression of inflammation, which may potentially lead to mitigation of hearing loss.
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24
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Elsherbiny NM, Ahmad S, Naime M, Elsherbini AM, Fulzele S, Al-Gayyar MM, Eissa LA, El-Shishtawy MM, Liou GI. ABT-702, an adenosine kinase inhibitor, attenuates inflammation in diabetic retinopathy. Life Sci 2013; 93:78-88. [PMID: 23770229 DOI: 10.1016/j.lfs.2013.05.024] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 04/29/2013] [Accepted: 05/28/2013] [Indexed: 12/20/2022]
Abstract
AIMS This study was undertaken to determine the effect of an adenosine kinase inhibitor (AKI) in diabetic retinopathy (DR). We have shown previously that adenosine signaling via A2A receptors (A2AAR) is involved in retinal protection from diabetes-induced inflammation. Here we demonstrate that AKI-enhanced adenosine signaling provides protection from DR in mice. MAIN METHODS We targeted AK, the key enzyme in adenosine metabolism, using a treatment regime with the selective AKI, ABT-702 (1.5mg/kg intraperitoneally twice a week) commencing at the beginning of streptozotocin-induced diabetes at the age of eight weeks. This treatment, previously demonstrated to increase free adenosine levels in vivo, was maintained until the age of 16 weeks. Retinal inflammation was evaluated using Western blot, Real-Time PCR and immuno-staining analyses. Role of A2AAR signaling in the anti-inflammation effect of ABT-702 was analyzed in Amadori-glycated-albumin (AGA)-treated microglial cells. KEY FINDINGS At 16 weeks, when diabetic mice exhibit significant signs of retinal inflammation including up-regulation of oxidative/nitrosative stress, A2AAR, ENT1, Iba1, TNF-α, ICAM1, retinal cell death, and down-regulation of AK, the ABT-702 treated group showed lower signs of inflammation compared to control animals receiving the vehicle. The involvement of adenosine signaling in the anti-inflammation effect of ABT-702 was supported by the TNF-α release blocking effect of A2AAR antagonist in AGA-treated microglial cells. SIGNIFICANCE These results suggest a role for AK in regulating adenosine receptor signaling in the retina. Inhibition of AK potentially amplifies the therapeutic effects of site- and event-specific accumulation of extracellular adenosine, which is of highly translational impact.
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25
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Abstract
Adenosine kinase (ADK; EC 2.7.1.20) is an evolutionarily conserved phosphotransferase that converts the purine ribonucleoside adenosine into 5'-adenosine-monophosphate. This enzymatic reaction plays a fundamental role in determining the tone of adenosine, which fulfills essential functions as a homeostatic and metabolic regulator in all living systems. Adenosine not only activates specific signaling pathways by activation of four types of adenosine receptors but it is also a primordial metabolite and regulator of biochemical enzyme reactions that couple to bioenergetic and epigenetic functions. By regulating adenosine, ADK can thus be identified as an upstream regulator of complex homeostatic and metabolic networks. Not surprisingly, ADK dysfunction is involved in several pathologies, including diabetes, epilepsy, and cancer. Consequently, ADK emerges as a rational therapeutic target, and adenosine-regulating drugs have been tested extensively. In recent attempts to improve specificity of treatment, localized therapies have been developed to augment adenosine signaling at sites of injury or pathology; those approaches include transplantation of stem cells with deletions of ADK or the use of gene therapy vectors to downregulate ADK expression. More recently, the first human mutations in ADK have been described, and novel findings suggest an unexpected role of ADK in a wider range of pathologies. ADK-regulating strategies thus represent innovative therapeutic opportunities to reconstruct network homeostasis in a multitude of conditions. This review will provide a comprehensive overview of the genetics, biochemistry, and pharmacology of ADK and will then focus on pathologies and therapeutic interventions. Challenges to translate ADK-based therapies into clinical use will be discussed critically.
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Affiliation(s)
- Detlev Boison
- Legacy Research Institute, 1225 NE 16th Ave, Portland, OR 97202, USA.
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