201
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Gao Z, Chen Y, Guan MX. Mitochondrial DNA mutations associated with aminoglycoside induced ototoxicity. J Otol 2017; 12:1-8. [PMID: 29937831 PMCID: PMC6011804 DOI: 10.1016/j.joto.2017.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 11/25/2022] Open
Abstract
Aminoglycosides (AmAn) are widely used for their great efficiency against gram-negative bacterial infections. However, they can also induce ototoxic hearing loss, which has affected millions of people around the world. As previously reported, individuals bearing mitochondrial DNA mutations in the 12S rRNA gene, such as m.1555A>G and m.1494C>T, are more prone to AmAn-induced ototoxicity. These mutations cause human mitochondrial ribosomes to more closely resemble bacterial ribosomes and enable a stronger aminoglycoside interaction. Consequently, exposure to AmAn can induce or worsen hearing loss in these individuals. Furthermore, a wide range of severity and penetrance of hearing loss was observed among families carrying these mutations. Studies have revealed that these mitochondria mutations are the primary molecular mechanism of genetic susceptibility to AmAn ototoxicity, though nuclear modifier genes and mitochondrial haplotypes are known to modulate the phenotypic manifestation.
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Affiliation(s)
- Zewen Gao
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Ye Chen
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Min-Xin Guan
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
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202
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Li J, Woo CW. Finding ways to solve or prevent aminoglycoside-induced ototoxicity? ANNALS OF TRANSLATIONAL MEDICINE 2017; 4:533. [PMID: 28149894 DOI: 10.21037/atm.2016.11.71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jin Li
- The State Key Laboratory of Pharmaceutical Biotechnology, the University of Hong Kong, Hong Kong SAR, China; Department of Medicine, the University of Hong Kong, Hong Kong SAR, China
| | - Connie W Woo
- The State Key Laboratory of Pharmaceutical Biotechnology, the University of Hong Kong, Hong Kong SAR, China; Department of Pharmacology and Pharmacy, the University of Hong Kong, Hong Kong SAR, China
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203
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Kim YJ, Tian C, Kim J, Shin B, Choo OS, Kim YS, Choung YH. Autophagic flux, a possible mechanism for delayed gentamicin-induced ototoxicity. Sci Rep 2017; 7:41356. [PMID: 28145495 PMCID: PMC5286410 DOI: 10.1038/srep41356] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 12/20/2016] [Indexed: 12/20/2022] Open
Abstract
Aminoglycoside antibiotics including gentamicin (GM) induce delayed ototoxic effects such as hearing loss after long-term use, unlike the early-onset ototoxicity caused by cisplatin. The purpose of the study was to identify the mechanism of the delayed GM-induced ototoxicity by exploring the role of autophagy in vitro and in vivo. Treating HEI-OC1 auditory cells with GM led to a time-dependent increase of the autophagosome marker LC3-II, which was accompanied by cell death. In contrast, cisplatin and penicillin caused a rapid increase and had no effect on LC3-II levels, respectively. LC3-II-expressing autophagosomes co-localized with the labeled GM. GM-treated autophagosomes expressed reduced levels of Rab7, which is necessary for the fusion of autophagosomes with lysosomes. When the autophagic flux enhancer rapamycin was applied to GM-treated cells, Rab7 and the lysosomal enzyme cathepsin D were upregulated, and increased cell survival was observed. In animal studies, the intraperitoneal injection of GM worsened hearing thresholds and induced the accumulation of LC3 in the organ of Corti. This hearing impairment was attenuated by rapamycin. These findings suggest that the delayed onset-ototoxicity of GM may be closely related to the accumulation of autophagosomes via impaired autophagy. This GM-induced auditory cell death could be inhibited by enhancing autophagic flux.
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Affiliation(s)
- Yeon Ju Kim
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
| | - Chunjie Tian
- Department of Otolaryngology, Dali Bai Autonomous Prefecture People's Hospital, Renminnan road 35, Dali, Yunnan 671000, China
| | - Jangho Kim
- Department of Rural and Biosystems Engineering, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Beomyong Shin
- Department of Biomedical Sciences, BK21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
| | - Oak-Sung Choo
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea.,Department of Medical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
| | - You-Sun Kim
- Department of Biomedical Sciences, BK21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
| | - Yun-Hoon Choung
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea.,Department of Biomedical Sciences, BK21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea.,Department of Medical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
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204
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Chaiyasap P, Srichomthong C, Tongkobpetch S, Suphapeetiporn K, Shotelersuk V. Identification of a mitochondrial 12S rRNA A1555G mutation causing aminoglycoside-induced deafness in a large Thai family. ASIAN BIOMED 2017. [DOI: 10.5372/1905-7415.0902.389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Abstract
Background
Hearing loss is among the most frequent sensory disorders. Preventable causes include medications given to genetically susceptible individuals. Several families around the world with an A1555G mitochondrial mutation who became profoundly deaf after receiving aminoglycosides have been described. However, none has been reported in Thailand.
Objectives
To identify the cause of hearing loss of a large Thai family with 11 members who reportedly turned deaf after receiving antibiotics.
Methods
We obtained blood samples from 5 members; 4 of whom had hearing loss. Mutation analyses were performed using molecular techniques including polymerase chain reaction, Sanger sequencing, and restriction fragment length polymorphism.
Results
All 4 affected members were found to harbor the same A1555G mitochondrial mutation, while the unaffected had only the wild-type A.
Conclusions
We have identified the mitochondrial mutation leading to aminoglycoside-induced hearing loss in a Thai population. Raising awareness for medical practitioners of this genetic susceptibility in Thailand is warranted. Avoidance of certain medications in these individuals would prevent this acquired permanent hearing loss.
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Affiliation(s)
- Pongsathorn Chaiyasap
- Interdepartment of Biomedical Sciences , Faculty of Graduate School , Chulalongkorn University , Bangkok 10330 , Thailand
| | - Chalurmpon Srichomthong
- Center of Excellence for Medical Genetics , Department of Pediatrics, Faculty of Medicine , Chulalongkorn University , Bangkok 10330 , Thailand
- Excellence Center for Medical Genetics , King Chulalongkorn Memorial Hospital, the Thai Red Cross , Bangkok 10330 , Thailand
| | - Siraprapa Tongkobpetch
- Center of Excellence for Medical Genetics , Department of Pediatrics, Faculty of Medicine , Chulalongkorn University , Bangkok 10330 , Thailand
- Excellence Center for Medical Genetics , King Chulalongkorn Memorial Hospital, the Thai Red Cross , Bangkok 10330 , Thailand
| | - Kanya Suphapeetiporn
- Center of Excellence for Medical Genetics , Department of Pediatrics, Faculty of Medicine , Chulalongkorn University , Bangkok 10330 , Thailand
- Excellence Center for Medical Genetics , King Chulalongkorn Memorial Hospital, the Thai Red Cross , Bangkok 10330 , Thailand
| | - Vorasuk Shotelersuk
- Center of Excellence for Medical Genetics , Department of Pediatrics, Faculty of Medicine , Chulalongkorn University , Bangkok 10330 , Thailand
- Excellence Center for Medical Genetics , King Chulalongkorn Memorial Hospital, the Thai Red Cross , Bangkok 10330 , Thailand
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205
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O’Sullivan ME, Perez A, Lin R, Sajjadi A, Ricci AJ, Cheng AG. Towards the Prevention of Aminoglycoside-Related Hearing Loss. Front Cell Neurosci 2017; 11:325. [PMID: 29093664 PMCID: PMC5651232 DOI: 10.3389/fncel.2017.00325] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 09/30/2017] [Indexed: 01/08/2023] Open
Abstract
Aminoglycosides are potent antibiotics deployed worldwide despite their known side-effect of sensorineural hearing loss. The main etiology of this sensory deficit is death of inner ear sensory hair cells selectively triggered by aminoglycosides. For decades, research has sought to unravel the molecular events mediating sensory cell demise, emphasizing the roles of reactive oxygen species and their potentials as therapeutic targets. Studies in recent years have revealed candidate transport pathways including the mechanotransducer channel for drug entry into sensory cells. Once inside sensory cells, intracellular targets of aminoglycosides, such as the mitochondrial ribosomes, are beginning to be elucidated. Based on these results, less ototoxic aminoglycoside analogs are being generated and may serve as alternate antimicrobial agents. In this article, we review the latest findings on mechanisms of aminoglycoside entry into hair cells, their intracellular actions and potential therapeutic targets for preventing aminoglycoside ototoxicity.
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Affiliation(s)
- Mary E. O’Sullivan
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Adela Perez
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Randy Lin
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Autefeh Sajjadi
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Anthony J. Ricci
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, United States
- *Correspondence: Anthony J. Ricci Alan G. Cheng
| | - Alan G. Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
- *Correspondence: Anthony J. Ricci Alan G. Cheng
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206
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Chang-Chien J, Yen YC, Li SY, Hsu TC, Yang JJ. Ferulic acid-mediated protection against neomycin-induced hair cell loss in transgenic zebrafish. J Funct Foods 2017. [DOI: 10.1016/j.jff.2016.11.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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207
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Hailey DW, Esterberg R, Linbo TH, Rubel EW, Raible DW. Fluorescent aminoglycosides reveal intracellular trafficking routes in mechanosensory hair cells. J Clin Invest 2016; 127:472-486. [PMID: 27991862 DOI: 10.1172/jci85052] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/03/2016] [Indexed: 11/17/2022] Open
Abstract
Aminoglycosides (AGs) are broad-spectrum antibiotics that are associated with kidney damage, balance disorders, and permanent hearing loss. This damage occurs primarily by killing of proximal tubule kidney cells and mechanosensory hair cells, though the mechanisms underlying cell death are not clear. Imaging molecules of interest in living cells can elucidate how molecules enter cells, traverse intracellular compartments, and interact with sites of activity. Here, we have imaged fluorescently labeled AGs in live zebrafish mechanosensory hair cells. We determined that AGs enter hair cells via both nonendocytic and endocytic pathways. Both routes deliver AGs from the extracellular space to lysosomes, and structural differences between AGs alter the efficiency of this delivery. AGs with slower delivery to lysosomes were immediately toxic to hair cells, and impeding lysosome delivery increased AG-induced death. Therefore, pro-death cascades induced at early time points of AG exposure do not appear to derive from the lysosome. Our findings help clarify how AGs induce hair cell death and reveal properties that predict toxicity. Establishing signatures for AG toxicity may enable more efficient evaluation of AG treatment paradigms and structural modifications to reduce hair cell damage. Further, this work demonstrates how following fluorescently labeled drugs at high resolution in living cells can reveal important details about how drugs of interest behave.
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208
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Keeling KM. Nonsense Suppression as an Approach to Treat Lysosomal Storage Diseases. Diseases 2016; 4:32. [PMID: 28367323 PMCID: PMC5370586 DOI: 10.3390/diseases4040032] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/14/2016] [Indexed: 02/08/2023] Open
Abstract
In-frame premature termination codons (PTCs) (also referred to as nonsense mutations) comprise ~10% of all disease-associated gene lesions. PTCs reduce gene expression in two ways. First, PTCs prematurely terminate translation of an mRNA, leading to the production of a truncated polypeptide that often lacks normal function and/or is unstable. Second, PTCs trigger degradation of an mRNA by activating nonsense-mediated mRNA decay (NMD), a cellular pathway that recognizes and degrades mRNAs containing a PTC. Thus, translation termination and NMD are putative therapeutic targets for the development of treatments for genetic diseases caused by PTCs. Over the past decade, significant progress has been made in the identification of compounds with the ability to suppress translation termination of PTCs (also referred to as readthrough). More recently, NMD inhibitors have also been explored as a way to enhance the efficiency of PTC suppression. Due to their relatively low threshold for correction, lysosomal storage diseases are a particularly relevant group of diseases to investigate the feasibility of nonsense suppression as a therapeutic approach. In this review, the current status of PTC suppression and NMD inhibition as potential treatments for lysosomal storage diseases will be discussed.
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Affiliation(s)
- Kim M Keeling
- Department of Biochemistry and Molecular Genetics, Gregory Fleming Cystic Fibrosis Research Center, Comprehensive Arthritis, Musculoskeletal, Bone, and Autoimmunity Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA; ; Tel.: +1-205-975-6585
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209
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Sagwa EL, Souverein PC, Ribeiro I, Leufkens HGM, Mantel-Teeuwisse AK. Differences in VigiBase® reporting of aminoglycoside and capreomycin-suspected ototoxicity during tuberculosis treatment. Pharmacoepidemiol Drug Saf 2016; 26:1-8. [DOI: 10.1002/pds.4125] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 10/14/2016] [Indexed: 12/28/2022]
Affiliation(s)
- Evans L. Sagwa
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences; Utrecht University; Utrecht The Netherlands
| | - Patrick C. Souverein
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences; Utrecht University; Utrecht The Netherlands
| | - Inês Ribeiro
- Centre for Health Technology Assessment and Drug Research; Association for Innovation and Biomedical Research on Light and Image; Coimbra Portugal
| | - Hubert G. M. Leufkens
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences; Utrecht University; Utrecht The Netherlands
| | - Aukje K. Mantel-Teeuwisse
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences; Utrecht University; Utrecht The Netherlands
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210
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Oh KH, Rah YC, Hwang KH, Lee SH, Kwon SY, Cha JH, Choi J. Melatonin mitigates neomycin-induced hair cell injury in zebrafish. Drug Chem Toxicol 2016; 40:390-396. [PMID: 27855522 DOI: 10.1080/01480545.2016.1244679] [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] [Indexed: 10/20/2022]
Abstract
CONTEXT Ototoxicity due to medications, such as aminoglycosides, is irreversible, and free radicals in the inner ear are assumed to play a major role. Because melatonin has an antioxidant property, we hypothesize that it might mitigate hair cell injury by aminoglycosides. OBJECTIVE The objective of this study was to evaluate whether melatonin has an alleviative effect on neomycin-induced hair cell injury in zebrafish (Danio rerio). METHODS Various concentrations of melatonin were administered to 5-day post-fertilization zebrafish treated with 125 μM neomycin for 1 h. Surviving hair cells within four neuromasts were compared with that of a control group. Apoptosis was assessed via terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. The changes of ultrastructure were confirmed using a scanning electron microscope. RESULTS Melatonin alleviated neomycin-induced hair cell injury in neuromasts (neomycin + melatonin 100 μM: 13.88 ± 0.91 cells, neomycin only: 7.85 ± 0.90 cells; n = 10, p < 0.05) and reduced neomycin-induced apoptosis in the TUNEL assay. In ultrastructural analysis, hair cells within the neuromasts in zebrafish were preserved exposed to 125 μM neomycin and 100 μM melatonin for 1 h in SEM findings. CONCLUSION Melatonin is effective in alleviating aminoglycoside-induced hair cell injury in zebrafish. The results of this study demonstrated that melatonin has the potential to reduce apoptosis induced by aminoglycosides in zebrafish.
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Affiliation(s)
- Kyoung Ho Oh
- a Department of Otorhinolaryngology-Head and Neck Surgery , Korea University College of Medicine , Seoul , South Korea and
| | - Yoon Chan Rah
- a Department of Otorhinolaryngology-Head and Neck Surgery , Korea University College of Medicine , Seoul , South Korea and
| | - Kyu Ho Hwang
- a Department of Otorhinolaryngology-Head and Neck Surgery , Korea University College of Medicine , Seoul , South Korea and
| | - Seung Hoon Lee
- a Department of Otorhinolaryngology-Head and Neck Surgery , Korea University College of Medicine , Seoul , South Korea and
| | - Soon Young Kwon
- a Department of Otorhinolaryngology-Head and Neck Surgery , Korea University College of Medicine , Seoul , South Korea and
| | - Jae Hyung Cha
- b Medical Science Research Center, Korea University College of Medicine , Ansan , South Korea
| | - June Choi
- a Department of Otorhinolaryngology-Head and Neck Surgery , Korea University College of Medicine , Seoul , South Korea and
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211
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Esterberg R, Linbo T, Pickett SB, Wu P, Ou HC, Rubel EW, Raible DW. Mitochondrial calcium uptake underlies ROS generation during aminoglycoside-induced hair cell death. J Clin Invest 2016; 126:3556-66. [PMID: 27500493 DOI: 10.1172/jci84939] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 06/09/2016] [Indexed: 12/11/2022] Open
Abstract
Exposure to aminoglycoside antibiotics can lead to the generation of toxic levels of reactive oxygen species (ROS) within mechanosensory hair cells of the inner ear that have been implicated in hearing and balance disorders. Better understanding of the origin of aminoglycoside-induced ROS could focus the development of therapies aimed at preventing this event. In this work, we used the zebrafish lateral line system to monitor the dynamic behavior of mitochondrial and cytoplasmic oxidation occurring within the same dying hair cell following exposure to aminoglycosides. The increased oxidation observed in both mitochondria and cytoplasm of dying hair cells was highly correlated with mitochondrial calcium uptake. Application of the mitochondrial uniporter inhibitor Ru360 reduced mitochondrial and cytoplasmic oxidation, suggesting that mitochondrial calcium drives ROS generation during aminoglycoside-induced hair cell death. Furthermore, targeting mitochondria with free radical scavengers conferred superior protection against aminoglycoside exposure compared with identical, untargeted scavengers. Our findings suggest that targeted therapies aimed at preventing mitochondrial oxidation have therapeutic potential to ameliorate the toxic effects of aminoglycoside exposure.
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212
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He Z, Sun S, Waqas M, Zhang X, Qian F, Cheng C, Zhang M, Zhang S, Wang Y, Tang M, Li H, Chai R. Reduced TRMU expression increases the sensitivity of hair-cell-like HEI-OC-1 cells to neomycin damage in vitro. Sci Rep 2016; 6:29621. [PMID: 27405449 PMCID: PMC4942793 DOI: 10.1038/srep29621] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/20/2016] [Indexed: 12/13/2022] Open
Abstract
Aminoglycosides are ototoxic to the cochlear hair cells, and mitochondrial dysfunction is one of the major mechanisms behind ototoxic drug-induced hair cell death. TRMU (tRNA 5-methylaminomethyl-2-thiouridylate methyltransferase) is a mitochondrial protein that participates in mitochondrial tRNA modifications, but the role of TRMU in aminoglycoside-induced ototoxicity remains to be elucidated. In this study, we took advantage of the HEI-OC-1 cell line to investigate the role of TRMU in aminoglycoside-induced cell death. We found that TRMU is expressed in both hair cells and HEI-OC-1 cells, and its expression is significantly decreased after 24 h neomycin treatment. We then downregulated TRMU expression with siRNA and found that cell death and apoptosis were significantly increased after neomycin injury. Furthermore, when we down-regulated TRMU expression, we observed significantly increased mitochondrial dysfunction and increased levels of reactive oxygen species (ROS) after neomycin injury, suggesting that TRMU regulates mitochondrial function and ROS levels. Lastly, the antioxidant N-acetylcysteine rescued the mitochondrial dysfunction and cell apoptosis that was induced by TRMU downregulation, suggesting that ROS accumulation contributed to the increased aminoglycosides sensitivity of HEI-OC-1 cells after TRMU downregulation. This study provides evidence that TRMU might be a new therapeutic target for the prevention of aminoglycoside-induced hair cell death.
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Affiliation(s)
- Zuhong He
- State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,MOE Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Shan Sun
- Department of Otorhinolaryngology, Hearing Research Institute, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China
| | - Muhammad Waqas
- State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,MOE Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Xiaoli Zhang
- Department of Otolaryngology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Fuping Qian
- State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,MOE Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Cheng Cheng
- State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,MOE Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Mingshu Zhang
- Medical School, Southeast University, Nanjing 210096, China
| | - Shasha Zhang
- State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,MOE Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Yongming Wang
- Institutes of Life Sciences, Fudan University, Shanghai 200032, China
| | - Mingliang Tang
- State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,MOE Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Huawei Li
- Department of Otorhinolaryngology, Hearing Research Institute, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China.,Institutes of Life Sciences, Fudan University, Shanghai 200032, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,MOE Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
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213
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Gentamicin Exposure and Sensorineural Hearing Loss in Preterm Infants. PLoS One 2016; 11:e0158806. [PMID: 27390846 PMCID: PMC4938424 DOI: 10.1371/journal.pone.0158806] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 06/22/2016] [Indexed: 11/21/2022] Open
Abstract
Objective To evaluate the impact of gentamicin exposure on sensorineural hearing loss (SNHL) in very low birth weight (VLBW) infants. Methods Exposure to gentamicin was determined in infants born between 1993 and 2010 at a gestational age < 32 weeks and/or with a birthweight < 1500 g, who presented with SNHL during the first 5 years of life. For each case, we selected two controls matched for gender, gestational age, birthweight, and year of birth. Results We identified 25 infants affected by SNHL, leading to an incidence of SNHL of 1.58% in our population of VLBW infants. The proportion of infants treated with gentamicin was 76% in the study group and 70% in controls (p = 0.78). The total cumulated dose of gentamicin administered did not differ between the study group (median 10.2 mg/kg, Q1-Q3 1.6–13.2) and the control group (median 7.9 mg/kg, Q1-Q3 0–12.8, p = 0.47). The median duration of gentamicin treatment was 3 days both in the study group and the control group (p = 0.58). Maximum predicted trough serum levels of gentamicin, cumulative area under the curve and gentamicin clearance were not different between cases and controls. Conclusion The impact of gentamicin on SNHL can be minimized with treatments of short duration, monitoring of blood levels and dose adjustment.
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214
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Foster J, Tekin M. Aminoglycoside induced ototoxicity associated with mitochondrial DNA mutations. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2016. [DOI: 10.1016/j.ejmhg.2016.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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215
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Jadali A, Kwan KY. Activation of PI3K signaling prevents aminoglycoside-induced hair cell death in the murine cochlea. Biol Open 2016; 5:698-708. [PMID: 27142333 PMCID: PMC4920183 DOI: 10.1242/bio.016758] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Accepted: 04/17/2016] [Indexed: 12/28/2022] Open
Abstract
Loss of sensory hair cells of the inner ear due to aminoglycoside exposure is a major cause of hearing loss. Using an immortalized multipotent otic progenitor (iMOP) cell line, specific signaling pathways that promote otic cell survival were identified. Of the signaling pathways identified, the PI3K pathway emerged as a strong candidate for promoting hair cell survival. In aging animals, components for active PI3K signaling are present but decrease in hair cells. In this study, we determined whether activated PI3K signaling in hair cells promotes survival. To activate PI3K signaling in hair cells, we used a small molecule inhibitor of PTEN or genetically ablated PTEN using a conditional knockout animal. Hair cell survival was challenged by addition of gentamicin to cochlear cultures. Hair cells with activated PI3K signaling were more resistant to aminoglycoside-induced hair cell death. These results indicate that increased PI3K signaling in hair cells promote survival and the PI3K signaling pathway is a target for preventing aminoglycoside-induced hearing loss.
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Affiliation(s)
- Azadeh Jadali
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA Stem Cell Research Center and Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Kelvin Y Kwan
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA Stem Cell Research Center and Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
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Kruger M, Boney R, Ordoobadi AJ, Sommers TF, Trapani JG, Coffin AB. Natural Bizbenzoquinoline Derivatives Protect Zebrafish Lateral Line Sensory Hair Cells from Aminoglycoside Toxicity. Front Cell Neurosci 2016; 10:83. [PMID: 27065807 PMCID: PMC4811916 DOI: 10.3389/fncel.2016.00083] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 03/16/2016] [Indexed: 01/24/2023] Open
Abstract
Moderate to severe hearing loss affects 360 million people worldwide and most often results from damage to sensory hair cells. Hair cell damage can result from aging, genetic mutations, excess noise exposure, and certain medications including aminoglycoside antibiotics. Aminoglycosides are effective at treating infections associated with cystic fibrosis and other life-threatening conditions such as sepsis, but cause hearing loss in 20–30% of patients. It is therefore imperative to develop new therapies to combat hearing loss and allow safe use of these potent antibiotics. We approach this drug discovery question using the larval zebrafish lateral line because zebrafish hair cells are structurally and functionally similar to mammalian inner ear hair cells and respond similarly to toxins. We screened a library of 502 natural compounds in order to identify novel hair cell protectants. Our screen identified four bisbenzylisoquinoline derivatives: berbamine, E6 berbamine, hernandezine, and isotetrandrine, each of which robustly protected hair cells from aminoglycoside-induced damage. Using fluorescence microscopy and electrophysiology, we demonstrated that the natural compounds confer protection by reducing antibiotic uptake into hair cells and showed that hair cells remain functional during and after incubation in E6 berbamine. We also determined that these natural compounds do not reduce antibiotic efficacy. Together, these natural compounds represent a novel source of possible otoprotective drugs that may offer therapeutic options for patients receiving aminoglycoside treatment.
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Affiliation(s)
- Matthew Kruger
- School of Biological Sciences, Washington State University Vancouver, WA, USA
| | - Robert Boney
- College of Arts and Sciences, Washington State University Vancouver, WA, USA
| | | | - Thomas F Sommers
- Department of Biology and Neuroscience Program, Amherst College Amherst, MA, USA
| | - Josef G Trapani
- Department of Biology and Neuroscience Program, Amherst College Amherst, MA, USA
| | - Allison B Coffin
- School of Biological Sciences, Washington State UniversityVancouver, WA, USA; College of Arts and Sciences, Washington State UniversityVancouver, WA, USA; Department of Integrative Physiology and Neuroscience, Washington State UniversityVancouver, WA, USA
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218
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Chang J, Choi J, Rah YC, Yoo MH, Oh KH, Im GJ, Lee SH, Kwon SY, Park HC, Chae SW, Jung HH. Sodium Selenite Acts as an Otoprotectant against Neomycin-Induced Hair Cell Damage in a Zebrafish Model. PLoS One 2016; 11:e0151557. [PMID: 26974429 PMCID: PMC4790947 DOI: 10.1371/journal.pone.0151557] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/01/2016] [Indexed: 01/13/2023] Open
Abstract
Sodium selenite is a trace element essential for many physiological functions in the body. It is involved in various biological processes; it acts as a cofactor for antioxidant enzymes that protect against free radicals and is reported to limit metal-mediated oxidative DNA damage. In the present study, we investigated the effect of sodium selenite on neomycin ototoxicity in wild-type and transgenic zebrafish (Brn3C: EGFP). Five or six days post-fertilization, zebrafish larvae were co-exposed to 125 μM neomycin and various concentrations (10 μM, 100 μM, 250 μM, and 500 μM) of sodium selenite for 1 h. Hair cells within neuromasts of the supraorbital (SO1 and SO2), otic (O1), and occipital (OC1) lateral lines were analyzed by fluorescence microscopy (n = 10 fish per treatment). Hair cell survival was estimated as the ratio of the hair cell numbers in each group compared to those of the control group that were not exposed to neomycin. Apoptosis and hair cell damage of neuromasts were evaluated using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) assay and 2-[4-(dimethylamino) styryl]-N-ethylpyridinium iodide (DASPEI) assay, respectively. Ultrastructural changes were evaluated using scanning electron microscopy and transmission electron microscopy. Neuromast hair cells were preserved in zebrafish exposed to 125 μM neomycin and 500 μM sodium selenite for 1 h. Sodium selenite protected against neomycin-induced hair cell loss of neuromasts, reduced apoptosis, and prevented zebrafish ultrastructural changes. We propose that sodium selenite protects against neomycin-induced hair cell damage by inhibiting apoptosis, decreasing the disarray of stereocilia, and preventing ultrastructural changes in the neuromast hair cells of the zebrafish.
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Affiliation(s)
- Jiwon Chang
- Department of Otorhinolaryngology-Head and Neck Surgery, Hallym University College of Medicine, Seoul, Korea
| | - June Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea
- * E-mail:
| | - Yoon Chan Rah
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea
| | - Myung Hoon Yoo
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea
| | - Kyoung Ho Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea
| | - Gi Jung Im
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea
| | - Seung Hoon Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea
| | - Soon Young Kwon
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea
| | - Hae-Chul Park
- Laboratory of Neurodevelopmental Genetics, Graduate School of Medicine, Korea University, Seoul, Korea
| | - Sung Won Chae
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea
| | - Hak Hyun Jung
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, Korea
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Galangin prevents aminoglycoside-induced ototoxicity by decreasing mitochondrial production of reactive oxygen species in mouse cochlear cultures. Toxicol Lett 2016; 245:78-85. [DOI: 10.1016/j.toxlet.2016.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 12/29/2015] [Accepted: 01/11/2016] [Indexed: 11/22/2022]
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The expression of NLRX1 in C57BL/6 mice cochlear hair cells: Possible relation to aging- and neomycin-induced deafness. Neurosci Lett 2016; 616:138-46. [PMID: 26836140 DOI: 10.1016/j.neulet.2015.11.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 11/22/2015] [Accepted: 11/23/2015] [Indexed: 12/21/2022]
Abstract
Nucleotide-binding domain and leucine-rich-repeat-containing family member X1 (NLRX1) is a cytoplasmic pattern recognition receptor that is predominantly located in mitochondria, which is tightly related to mitochondrial damage, reactive oxygen species (ROS) production, inflammation and apoptosis. The present study was designed to explore whether NLRX1 expresses in C57BL/6 mice cochlear hair cells and, if so, to investigate the possible correlations between NLRX1 and hearing. The location and dynamic expression of NLRX1 were investigated by immunofluorescence, real-time PCR and Western blotting. Hearing thresholds of C57BL/6 mice were measured by auditory brainstem response (ABR). Moreover, the downstream inflammatory and apoptotic pathways regulated by NLRX1 were examined in age-related and neomycin-induced hair cell damage. Data showed that NLRX1 expressed in cytoplasm of C57BL/6 cochlear hair cells, especially in the cilia, which were essential for sound sensation. The expression of NLRX1 in hair cells increased as the mice grew up, and, decreased as they aged. Additionally, the activated apoptotic JNK pathway was detected in 9-month old mice with worse-hearing and 3-month old mice treated with neomycin. Overall, results indicate that NLRX1 may relate to hair cell maturity, hearing formation and maintenance, and promote hair cell apoptosis through JNK pathway induced by aging and neomycin.
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221
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Azadeh J, Song Z, Laureano AS, Toro-Ramos A, Kwan K. Initiating Differentiation in Immortalized Multipotent Otic Progenitor Cells. J Vis Exp 2016. [PMID: 26780605 DOI: 10.3791/53692] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Use of human induced pluripotent stem cells (iPSC) or embryonic stem cells (ESC) for cell replacement therapies holds great promise. Several limitations including low yields and heterogeneous populations of differentiated cells hinder the progress of stem cell therapies. A fate restricted immortalized multipotent otic progenitor (iMOP) cell line was generated to facilitate efficient differentiation of large numbers of functional hair cells and spiral ganglion neurons (SGN) for inner ear cell replacement therapies. Starting from dissociated cultures of single iMOP cells, protocols that promote cell cycle exit and differentiation by basic fibroblast growth factor (bFGF) withdrawal were described. A significant decrease in proliferating cells after bFGF withdrawal was confirmed using an EdU cell proliferation assay. Concomitant with a decrease in proliferation, successful differentiation resulted in expression of molecular markers and morphological changes. Immunostaining of Cdkn1b (p27(KIP)) and Cdh1 (E-cadherin) in iMOP-derived otospheres was used as an indicator for differentiation into inner ear sensory epithelia while immunostaining of Cdkn1b and Tubb3 (neuronal β-tubulin) was used to identify iMOP-derived neurons. Use of iMOP cells provides an important tool for understanding cell fate decisions made by inner ear neurosensory progenitors and will help develop protocols for generating large numbers of iPSC or ESC-derived hair cells and SGNs. These methods will accelerate efforts for generating otic cells for replacement therapies.
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Affiliation(s)
| | | | | | | | - Kelvin Kwan
- Cell Biology & Neuroscience, Rutgers University;
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Abstract
Tuberculosis (TB) remains a major public health problem, representing the second leading cause of death from infectious diseases globally, despite being nearly 100 % curable. Multidrug-resistant (MDR)-TB, a form of TB resistant to isoniazid and rifampicin (rifampin), two of the key first-line TB drugs, is becoming increasingly common. MDR-TB is treated with a combination of drugs that are less effective but more toxic than isoniazid and rifampicin. These drugs include fluoroquinolones, aminoglycosides, ethionamide, cycloserine, aminosalicyclic acid, linezolid and clofazimine among others. Minor adverse effects are quite common and they can be easily managed with symptomatic treatment. However, some adverse effects can be life-threatening, e.g. nephrotoxicity due to aminoglycosides, cardiotoxicity due to fluoroquinolones, gastrointestinal toxicity due to ethionamide or para-aminosalicylic acid, central nervous system toxicity due to cycloserine, etc. Baseline evaluation may help to identify patients who are at increased risk for adverse effects. Regular clinical and laboratory evaluation during treatment is very important to prevent adverse effects from becoming serious. Timely and intensive monitoring for, and management of adverse effects caused by, second-line drugs are essential components of drug-resistant TB control programmes; poor management of adverse effects increases the risk of non-adherence or irregular adherence to treatment, and may result in death or permanent morbidity. Treating physicians should have a thorough knowledge of the adverse effects associated with the use of second-line anti-TB drugs, and routinely monitor the occurrence of adverse drug reactions. In this review, we have compiled safety and tolerability information regarding second-line anti-TB drugs in both adults and children.
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223
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Sagwa EL, Ruswa N, Mavhunga F, Rennie T, Leufkens HGM, Mantel-Teeuwisse AK. Comparing amikacin and kanamycin-induced hearing loss in multidrug-resistant tuberculosis treatment under programmatic conditions in a Namibian retrospective cohort. BMC Pharmacol Toxicol 2015; 16:36. [PMID: 26654443 PMCID: PMC4675035 DOI: 10.1186/s40360-015-0036-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 11/18/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Amikacin and kanamycin are mainly used for treating multidrug-resistant tuberculosis (MDR-TB), especially in developing countries where the burden of MDR-TB is highest. Their protracted use in MDR-TB treatment is known to cause dose-dependent irreversible hearing loss, requiring hearing aids, cochlear implants or rehabilitation. Therapeutic drug monitoring and regular audiological assessments may help to prevent or detect the onset of hearing loss, but these services are not always available or affordable in many developing countries. We aimed to compare the cumulative incidence of hearing loss among patients treated for MDR-TB with amikacin or kanamycin-based regimens, and to identify the most-at-risk patients, based on the real-life clinical practice experiences in Namibia. METHODS We conducted a retrospective cohort study of patients treated with amikacin or kanamycin-based regimens in four public sector MDR-TB treatment sites in Namibia between June 2004 and March 2014. Patients were audiologically assessed as part of clinical care. The study outcome was the occurrence of any hearing loss. Data were manually extracted from patients' treatment records. We compared proportions using the Chi-square test; applied stratified analysis and logistic regression to study the risk of hearing loss and to identify the most-at-risk patients through effect-modification analysis. A P-value < 0.05 was statistically significant. RESULTS All 353 patients had normal baseline hearing, 46 % were HIV co-infected. Cumulative incidence of any hearing loss was 58 %, which was mostly bilateral (83 %), and mild (32 %), moderate (23 %), moderate-severe (16 %), severe (10 %), or profound (15 %). Patients using amikacin had a greater risk of developing the more severe forms of hearing loss than those using kanamycin (adjusted odds ratio (OR) = 4.0, 95 % CI: 1.5-10.8). Patients co-infected with HIV (OR = 3.4, 95 % CI: 1.1-10.6), males (OR = 4.5, 95 %1.5-13.4) and those with lower baseline body weight (40-59 kg, OR = 2.8, 95 % CI: 1.1-6.8), were most-at-risk of developing hearing loss. CONCLUSION Amikacin use in the long-term MDR-TB treatment led to a higher risk of occurrence of the more severe forms of hearing loss compared to kanamycin use. Males, patients with low baseline body weight and those co-infected with HIV were most-at-risk. MDR-TB treatment programmes should consider replacing amikacin with kanamycin and strengthen the routine renal, serum therapeutic drug levels and audiometric monitoring in the most-at-risk patients treated with aminoglycosides.
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Affiliation(s)
- Evans L Sagwa
- Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
| | - Nunurai Ruswa
- National Tuberculosis and Leprosy Program, Windhoek, Namibia
| | - Farai Mavhunga
- National Tuberculosis and Leprosy Program, Windhoek, Namibia
| | - Timothy Rennie
- University of Namibia School of Pharmacy, Windhoek, Namibia
| | - Hubert G M Leufkens
- Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
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Rah YC, Choi J, Yoo MH, Yum G, Park S, Oh KH, Lee SH, Kwon SY, Cho SH, Kim S, Park HC. Ecabet sodium alleviates neomycin-induced hair cell damage. Free Radic Biol Med 2015; 89:1176-83. [PMID: 26561773 DOI: 10.1016/j.freeradbiomed.2015.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/13/2015] [Accepted: 11/06/2015] [Indexed: 02/04/2023]
Abstract
Ecabet sodium (ES) is currently applied to some clinical gastrointestinal disease primarily by the inhibition of the ROS production. In this study, the protective role of ES was evaluated against the neomycin-induced hair cell loss using zebrafish experimental animal model. Zebrafish larvae (5-7 dpf), were treated with each of the following concentrations of ES: 5, 10, 20, 40, and 80 μg/mL for 1 h, followed by 125 μM neomycin for 1h. The positive control group was established by 125 μM neomycin-only treatment (1h) and the negative control group with no additional chemicals was also established. Hair cells inside four neuromasts ( SO1, SO2, O1, OC1) were assessed using fluorescence microscopy (n = 10). Hair cell survival was calculated as the mean number of viable hair cells for each group. Apoptosis and mitochondrial damage were investigated using special staining (TUNEL and DASPEI assay, respectively), and compared among groups. Ultrastructural changes were evaluated using scanning electron microscopy. Pre-treatment group with ES increased the mean number of viable hair cells as a dose-dependent manner achieving almost same number of viable hair cells with 40 μM/ml ES treatment (12.98 ± 2.59 cells) comparing to that of the negative control group (14.15 ± 1.39 cells, p = 0.72) and significantly more number of viable hair cells than that of the positive control group (7.45 ± 0.91 cells, p < 0.01). The production of reactive oxygen species significantly increased by 183% with 125 μM neomycin treatment than the negative control group and significantly decreased down to 105% with the pre-treatment with 40 μM/ml ES (n = 40, p = 0.04). A significantly less number of TUNEL-positive cells (reflecting apoptosis, p < 0.01) and a significantly increased DASPEI reactivity (reflecting viable mitochondria, p < 0.01) were observed in 40 μM/ml ES pre-treatment group. Our data suggest that ES could protect against neomycin-induced hair cell loss possibly by reducing apoptosis, mitochondrial damages, and the ROS generation.
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Affiliation(s)
- Yoon Chan Rah
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
| | - June Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea.
| | - Myung Hoon Yoo
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
| | - Gunhwee Yum
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
| | - Saemi Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
| | - Kyoung Ho Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
| | - Seung Hoon Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
| | - Soon Young Kwon
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
| | | | - Suhyun Kim
- Laboratory of Neurodevelopmental Genetics, Graduate School of Medicine, Korea University, Seoul, Republic of Korea
| | - Hae-Chul Park
- Laboratory of Neurodevelopmental Genetics, Graduate School of Medicine, Korea University, Seoul, Republic of Korea
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Fan C, Zou S, Wang J, Zhang B, Song J. Neomycin damage and regeneration of hair cells in both mechanoreceptor and electroreceptor lateral line organs of the larval Siberian sturgeon (Acipenser baerii
). J Comp Neurol 2015; 524:1443-56. [DOI: 10.1002/cne.23918] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 10/16/2015] [Accepted: 10/17/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Chunxin Fan
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education; Shanghai China
- Institute for Marine Biosystem and Neuroscience, International Center for Marine Studies, Shanghai Ocean University; Shanghai China
| | - Sha Zou
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education; Shanghai China
- Institute for Marine Biosystem and Neuroscience, International Center for Marine Studies, Shanghai Ocean University; Shanghai China
| | - Jian Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education; Shanghai China
| | - Bo Zhang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education; Shanghai China
- Institute for Marine Biosystem and Neuroscience, International Center for Marine Studies, Shanghai Ocean University; Shanghai China
| | - Jiakun Song
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education; Shanghai China
- Institute for Marine Biosystem and Neuroscience, International Center for Marine Studies, Shanghai Ocean University; Shanghai China
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226
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Musiime GM, Seale AC, Moxon SG, Lawn JE. Risk of gentamicin toxicity in neonates treated for possible severe bacterial infection in low- and middle-income countries: Systematic Review. Trop Med Int Health 2015; 20:1593-606. [PMID: 26426298 DOI: 10.1111/tmi.12608] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVES To assess the risk of gentamicin toxicity and potential number of neonates exposed annually to this risk, through treatment with WHO-recommended first-line antibiotics (gentamicin with penicillin) for the 6.9 million neonates with possible serious bacterial infection (PSBI). METHODS Systematic literature review and assessment of the evidence using Cochrane and GRADE criteria. Meta-analysis was undertaken for pooled estimates where appropriate. RESULTS Eleven studies (946 neonates) were included (nine randomised controlled trials and two prospective cohort studies). Six trials reported consistently measured ototoxicity outcomes in neonates treated with gentamicin, and the pooled estimate for hearing loss was 3% (95% CI 0-7%). Nephrotoxicity could not be assessed due to variation in case definitions used. Estimates of the number of neonates potentially affected by gentamicin toxicity were not undertaken due to insufficient data. CONCLUSION Given wider scale-up of outpatient-based and lower-level treatment of PSBI, improved data are essential to better assess the risks from neonatal gentamicin treatment without assessment of blood levels, to maximise benefit and reduce harm.
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Affiliation(s)
| | - Anna C Seale
- Department of Infectious Diseases Informatics, University College London, London, UK.,Centre for Maternal, Adolescent, Reproductive and Child Health (MARCH), and Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Sarah G Moxon
- Centre for Maternal, Adolescent, Reproductive and Child Health (MARCH), and Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Joy E Lawn
- Centre for Maternal, Adolescent, Reproductive and Child Health (MARCH), and Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
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Kato T, Yang G, Teo Y, Juskeviciene R, Perez-Fernandez D, Shinde HM, Salian S, Bernet B, Vasella A, Böttger EC, Crich D. Synthesis and Antiribosomal Activities of 4'-O-, 6'-O-, 4″-O-, 4',6'-O- and 4″,6″-O-Derivatives in the Kanamycin Series Indicate Differing Target Selectivity Patterns between the 4,5- and 4,6-Series of Disubstituted 2-Deoxystreptamine Aminoglycoside Antibiotics. ACS Infect Dis 2015; 1:479-86. [PMID: 27623314 DOI: 10.1021/acsinfecdis.5b00069] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Chemistry for the efficient modification of the kanamycin class of 4,6-aminoglycosides at the 4'-position is presented. In all kanamycins but kanamycin B, 4'-O-alkylation is strongly detrimental to antiribosomal and antibacterial activity. Ethylation of kanamycin B at the 4″-position entails little loss of antiribosomal and antibacterial activity, but no increase of ribosomal selectivity. These results are contrasted with those for the 4,5-aminoglycosides, where 4'-O-alkylation of paromomycin causes only a minimal loss of activity but results in a significant increase in selectivity with a concomitant loss of ototoxicity.
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Affiliation(s)
- Takayuki Kato
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Guanyu Yang
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Youjin Teo
- Institut für Medizinische Mikrobiologie, Universität Zürich, 8006 Zürich, Switzerland
| | - Reda Juskeviciene
- Institut für Medizinische Mikrobiologie, Universität Zürich, 8006 Zürich, Switzerland
| | | | - Harish M. Shinde
- Laboratorium für Organische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - Sumanth Salian
- Laboratorium für Organische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - Bruno Bernet
- Laboratorium für Organische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - Andrea Vasella
- Laboratorium für Organische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - Erik C. Böttger
- Institut für Medizinische Mikrobiologie, Universität Zürich, 8006 Zürich, Switzerland
| | - David Crich
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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Maarup TJ, Chen AH, Porter FD, Farhat NY, Ory DS, Sidhu R, Jiang X, Dickson PI. Intrathecal 2-hydroxypropyl-beta-cyclodextrin in a single patient with Niemann-Pick C1. Mol Genet Metab 2015; 116:75-9. [PMID: 26189084 PMCID: PMC4633280 DOI: 10.1016/j.ymgme.2015.07.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 07/06/2015] [Accepted: 07/06/2015] [Indexed: 11/28/2022]
Abstract
Niemann-Pick C, type 1 (NPC1) is a progressive autosomal recessive neurologic disease caused by defective intracellular cholesterol and lipid trafficking. There are currently no United States Food and Drug Administration approved treatments for NPC1. We undertook a study evaluating the safety, efficacy, and biomarker response of intrathecal 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in a 12-year old subject with mildly symptomatic NPC. The subject received 200mg intrathecal HP-β-CD administered biweekly via lumbar puncture. To date the subject has received 27 intrathecal HP-β-CD injections. Intrathecal HP-β-CD has been generally safe and well tolerated in this subject. There has been an improvement in vertical gaze. The subject has developed subclinical hearing loss at high frequency that is likely HP-β-CD related. Plasma 24-(S)-hydroxycholesterol, a pharmacodynamic biomarker for cholesterol redistribution in the central nervous system, was significantly increased in response to each of the first 5 drug administrations. Further dosing as well as dose escalations are needed to more completely ascertain the safety and efficacy of intrathecal HP-β-CD.
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Affiliation(s)
- Timothy J Maarup
- Department of Pediatrics, Division of Medical Genetics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA.
| | - Agnes H Chen
- Department of Pediatrics, Division of Neurology, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Forbes D Porter
- Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, DHHS, Bethesda, MD, USA
| | - Nicole Y Farhat
- Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, DHHS, Bethesda, MD, USA
| | - Daniel S Ory
- Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St Louis, MO, USA
| | - Rohini Sidhu
- Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St Louis, MO, USA
| | - Xuntian Jiang
- Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St Louis, MO, USA
| | - Patricia I Dickson
- Department of Pediatrics, Division of Medical Genetics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
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229
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Yang CH, Schrepfer T, Schacht J. Age-related hearing impairment and the triad of acquired hearing loss. Front Cell Neurosci 2015; 9:276. [PMID: 26283913 PMCID: PMC4515558 DOI: 10.3389/fncel.2015.00276] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 07/06/2015] [Indexed: 02/03/2023] Open
Abstract
Understanding underlying pathological mechanisms is prerequisite for a sensible design of protective therapies against hearing loss. The triad of age-related, noise-generated, and drug-induced hearing loss displays intriguing similarities in some cellular responses of cochlear sensory cells such as a potential involvement of reactive oxygen species (ROS) and apoptotic and necrotic cell death. On the other hand, detailed studies have revealed that molecular pathways are considerably complex and, importantly, it has become clear that pharmacological protection successful against one form of hearing loss will not necessarily protect against another. This review will summarize pathological and pathophysiological features of age-related hearing impairment (ARHI) in human and animal models and address selected aspects of the commonality (or lack thereof) of cellular responses in ARHI to drugs and noise.
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Affiliation(s)
- Chao-Hui Yang
- Department of Otolaryngology, Kresge Hearing Research Institute, University of Michigan Ann Arbor, MI, USA ; Division of Otology, Department of Otolaryngology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine Kaohsiung, Taiwan
| | - Thomas Schrepfer
- Department of Otolaryngology, Kresge Hearing Research Institute, University of Michigan Ann Arbor, MI, USA
| | - Jochen Schacht
- Department of Otolaryngology, Kresge Hearing Research Institute, University of Michigan Ann Arbor, MI, USA
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230
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Schellack N, Wium AM, Ehlert K, van Aswegen Y, Gous A. Establishing a pharmacotherapy induced ototoxicity programme within a service-learning approach. SOUTH AFRICAN JOURNAL OF COMMUNICATION DISORDERS 2015; 62:E1-7. [PMID: 26304216 PMCID: PMC5843252 DOI: 10.4102/sajcd.v62i1.96] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 04/23/2015] [Accepted: 04/04/2015] [Indexed: 01/20/2023] Open
Abstract
Pharmacotherapy-induced ototoxicity is growing, especially in developing countries such as South Africa. This highlights the importance of ototoxicity monitoring and management of hearing loss. This article focuses on the establishment of an ototoxicity clinic as a site for the implementation of a service-learning module in the Audiology programme. The clinic offers a unique opportunity of collaboration between pharmacists and an audiologist where pharmacotherapy-induced ototoxicity is uniquely monitored. The Sefako Makgatho Health Sciences University (SMU) provides training to both the disciplines, audiology and pharmacy. The main aim of this article is to describe how ototoxicity monitoring is implemented in the curriculum within such an academic service-learning approach. Through service learning students develop a deeper understanding of course content, acquire new knowledge and engage in civic activity. It simultaneously provides a unique opportunity for interdisciplinary collaboration between the disciplines of audiology and pharmacy. The objectives for this programme are therefore to facilitate learning and to provide a service to the local community by identifying, preventing and monitoring medicine-induced hearing loss in in-hospital and out-patients; as well as to establish inter-disciplinary collaboration between the disciplines and stakeholders for more effective service delivery. The constant interdisciplinary teamwork between the audiologist, pharmacist, physician and nursing staff in the wards results in best practice and management of patients with ototoxic damage.
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231
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Pinto-Teixeira F, Viader-Llargués O, Torres-Mejía E, Turan M, González-Gualda E, Pola-Morell L, López-Schier H. Inexhaustible hair-cell regeneration in young and aged zebrafish. Biol Open 2015; 4:903-9. [PMID: 26002931 PMCID: PMC4571094 DOI: 10.1242/bio.012112] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Animals have evolved two general strategies to counter injury and maintain physiological function. The most prevalent is protection by isolating vital organs into body cavities. However, protection is not optimal for sensory systems because their external components need to be exposed to the environment to fulfill their receptive function. Thus, a common strategy to maintain sensory abilities against persistent environmental insult involves repair and regeneration. However, whether age or frequent injuries affect the regenerative capacity of sensory organs remains unknown. We have found that neuromasts of the zebrafish lateral line regenerate mechanosensory hair cells after recurrent severe injuries and in adulthood. Moreover, neuromasts can reverse transient imbalances of Notch signaling that result in defective organ proportions during repair. Our results reveal inextinguishable hair-cell regeneration in the lateral line, and suggest that the neuromast epithelium is formed by plastic territories that are maintained by continuous intercellular communication.
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Affiliation(s)
- Filipe Pinto-Teixeira
- Laboratory of Sensory Cell Biology & Organogenesis, Centre for Genomic Regulation, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Oriol Viader-Llargués
- Laboratory of Sensory Cell Biology & Organogenesis, Centre for Genomic Regulation, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Elen Torres-Mejía
- Laboratory of Sensory Cell Biology & Organogenesis, Centre for Genomic Regulation, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Melissa Turan
- Laboratory of Sensory Cell Biology & Organogenesis, Centre for Genomic Regulation, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Estela González-Gualda
- Laboratory of Sensory Cell Biology & Organogenesis, Centre for Genomic Regulation, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Laura Pola-Morell
- Laboratory of Sensory Cell Biology & Organogenesis, Centre for Genomic Regulation, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Hernán López-Schier
- Laboratory of Sensory Cell Biology & Organogenesis, Centre for Genomic Regulation, Dr. Aiguader 88, 08003 Barcelona, Spain
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232
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Tao L, Segil N. Early transcriptional response to aminoglycoside antibiotic suggests alternate pathways leading to apoptosis in sensory hair cells in the mouse inner ear. Front Cell Neurosci 2015; 9:190. [PMID: 26052268 PMCID: PMC4439550 DOI: 10.3389/fncel.2015.00190] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/29/2015] [Indexed: 01/22/2023] Open
Abstract
Aminoglycoside antibiotics are “the drug of choice” for treating many bacterial infections, but their administration results in hearing loss in up to one fourth of the patients who receive them. Several biochemical pathways have been implicated in aminoglycoside antibiotic ototoxicity; however, little is known about how hair cells respond to aminoglycoside antibiotics at the transcriptome level. Here we have investigated the genome-wide response to the aminoglycoside antibiotic gentamicin. Using organotypic cultures of the perinatal organ of Corti, we performed RNA sequencing using cDNA libraries obtained from FACS-purified hair cells. Within 3 h of gentamicin treatment, the messenger RNA level of more than three thousand genes in hair cells changed significantly. Bioinformatic analysis of these changes highlighted several known signal transduction pathways, including the JNK pathway and the NF-κB pathway, in addition to genes involved in the stress response, apoptosis, cell cycle control, and DNA damage repair. In contrast, only 698 genes, mainly involved in cell cycle and metabolite biosynthetic processes, were significantly affected in the non-hair cell population. The gene expression profiles of hair cells in response to gentamicin share a considerable similarity with those previously observed in gentamicin-induced nephrotoxicity. Our findings suggest that previously observed early responses to gentamicin in hair cells in specific signaling pathways are reflected in changes in gene expression. Additionally, the observed changes in gene expression of cell cycle regulatory genes indicate a disruption of the postmitotic state, which may suggest an alternate pathway regulating gentamicin-induced apoptotic hair cell death. This work provides a more comprehensive view of aminoglycoside antibiotic ototoxicity, and thus contributes to identifying potential pathways or therapeutic targets to alleviate this important side effect of aminoglycoside antibiotics.
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Affiliation(s)
- Litao Tao
- Genetic, Molecular and Cellular Biology Program, University of Southern California Los Angeles, CA, USA ; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California Los Angeles, CA, USA
| | - Neil Segil
- Genetic, Molecular and Cellular Biology Program, University of Southern California Los Angeles, CA, USA ; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California Los Angeles, CA, USA ; Department of Otolaryngology, University of Southern California Los Angeles, CA, USA
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233
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Affiliation(s)
- P Garcia-Huerta
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - A Rivas
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - C Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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234
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Zholudeva LV, Ward KG, Nichols MG, Smith HJ. Gentamicin differentially alters cellular metabolism of cochlear hair cells as revealed by NAD(P)H fluorescence lifetime imaging. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:051032. [PMID: 25688541 PMCID: PMC4405084 DOI: 10.1117/1.jbo.20.5.051032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 01/15/2015] [Indexed: 06/04/2023]
Abstract
Aminoglycoside antibiotics are implicated as culprits of hearing loss in more than 120,000 individuals annually. Research has shown that the sensory cells, but not supporting cells, of the cochlea are readily damaged and/or lost after use of such antibiotics. High-frequency outer hair cells (OHCs) show a greater sensitivity to antibiotics than high- and low-frequency inner hair cells (IHCs). We hypothesize that variations in mitochondrial metabolism account for differences in susceptibility. Fluorescence lifetime microscopy was used to quantify changes in NAD(P)H in sensory and supporting cells from explanted murine cochleae exposed to mitochondrial uncouplers, inhibitors, and an ototoxic antibiotic, gentamicin (GM). Changes in metabolic state resulted in a redistribution of NAD(P)H between subcellular fluorescence lifetime pools. Supporting cells had a significantly longer lifetime than sensory cells. Pretreatment with GM increased NAD(P)H intensity in high-frequency sensory cells, as well as the NAD(P)H lifetime within IHCs. GM specifically increased NAD(P)H concentration in high-frequency OHCs, but not in IHCs or pillar cells. Variations in NAD(P)H intensity in response to mitochondrial toxins and GM were greatest in high-frequency OHCs. These results demonstrate that GM rapidly alters mitochondrial metabolism, differentially modulates cell metabolism, and provides evidence that GM-induced changes in metabolism are significant and greatest in high-frequency OHCs.
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Affiliation(s)
- Lyandysha V. Zholudeva
- Drexel University, Department of Neurobiology and Anatomy, 2900 West Queen Lane, Philadelphia, Pennsylvania 19129, United States
| | - Kristina G. Ward
- Creighton University, Department of Physics, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Michael G. Nichols
- Creighton University, Department of Physics, 2500 California Plaza, Omaha, Nebraska 68178, United States
- Creighton University, Department of Biomedical Sciences, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Heather Jensen Smith
- Creighton University, Department of Biomedical Sciences, 2500 California Plaza, Omaha, Nebraska 68178, United States
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235
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Reactive oxygen species, apoptosis, and mitochondrial dysfunction in hearing loss. BIOMED RESEARCH INTERNATIONAL 2015; 2015:617207. [PMID: 25874222 PMCID: PMC4385658 DOI: 10.1155/2015/617207] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 09/10/2014] [Indexed: 12/20/2022]
Abstract
Reactive oxygen species (ROS) production is involved in several apoptotic and necrotic cell death pathways in auditory tissues. These pathways are the major causes of most types of sensorineural hearing loss, including age-related hearing loss, hereditary hearing loss, ototoxic drug-induced hearing loss, and noise-induced hearing loss. ROS production can be triggered by dysfunctional mitochondrial oxidative phosphorylation and increases or decreases in ROS-related enzymes. Although apoptotic cell death pathways are mostly activated by ROS production, there are other pathways involved in hearing loss that do not depend on ROS production. Further studies of other pathways, such as endoplasmic reticulum stress and necrotic cell death, are required.
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236
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Stawicki TM, Esterberg R, Hailey DW, Raible DW, Rubel EW. Using the zebrafish lateral line to uncover novel mechanisms of action and prevention in drug-induced hair cell death. Front Cell Neurosci 2015; 9:46. [PMID: 25741241 PMCID: PMC4332341 DOI: 10.3389/fncel.2015.00046] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/30/2015] [Indexed: 01/01/2023] Open
Abstract
The majority of hearing loss and balance disorders are caused by the permanent loss of mechanosensory hair cells of the inner ear. Identification of genes and compounds that modulate susceptibility to hair cell death is frequently confounded by the difficulties of assaying for such complex phenomena in mammalian models. The zebrafish has emerged as a powerful animal model for genetic and chemical screening in many contexts. Several characteristics of the zebrafish, such as its small size and external location of mechanosensory hair cells within the lateral line sensory organ, uniquely position it as an ideal model organism for the study of hair cell toxicity. We have used this model to screen for genes and compounds that affect hair cell survival during ototoxin exposure and have identified agents that would not be expected to play a role in this process based on a priori knowledge of their function. The identification of such agents yields better understanding of hair cell death and holds promise to stem hearing loss and balance disorders in the human population.
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Affiliation(s)
- Tamara M Stawicki
- Virginia Merrill Bloedel Hearing Research Center, University of Washington Seattle, WA, USA ; Department of Biological Structure, University of Washington Seattle, WA, USA
| | - Robert Esterberg
- Virginia Merrill Bloedel Hearing Research Center, University of Washington Seattle, WA, USA ; Department of Otolaryngology, Head and Neck Surgery, University of Washington Seattle, WA, USA
| | - Dale W Hailey
- Virginia Merrill Bloedel Hearing Research Center, University of Washington Seattle, WA, USA ; Department of Biological Structure, University of Washington Seattle, WA, USA
| | - David W Raible
- Virginia Merrill Bloedel Hearing Research Center, University of Washington Seattle, WA, USA ; Department of Biological Structure, University of Washington Seattle, WA, USA
| | - Edwin W Rubel
- Virginia Merrill Bloedel Hearing Research Center, University of Washington Seattle, WA, USA ; Department of Otolaryngology, Head and Neck Surgery, University of Washington Seattle, WA, USA
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237
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Sun S, Yu H, Yu H, Honglin M, Ni W, Zhang Y, Guo L, He Y, Xue Z, Ni Y, Li J, Feng Y, Chen Y, Shao R, Chai R, Li H. Inhibition of the activation and recruitment of microglia-like cells protects against neomycin-induced ototoxicity. Mol Neurobiol 2015; 51:252-67. [PMID: 24781382 DOI: 10.1007/s12035-014-8712-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/09/2014] [Indexed: 12/18/2022]
Abstract
One of the most unfortunate side effects of aminoglycoside (AG) antibiotics such as neomycin is that they target sensory hair cells (HCs) and can cause permanent hearing impairment. We have observed HC loss and microglia-like cell (MLC) activation in the inner ear (cochlea) following neomycin administration. We focused on CX3CL1, a membrane-bound glycoprotein expressed on neurons and endothelial cells, as a way to understand how the MLCs are activated and the role these cells play in HC loss. CX3CL1 is the exclusive ligand for CX3CR1, which is a chemokine receptor expressed on the surface of macrophages and MLCs. In vitro experiments showed that the expression levels of CX3CL1 and CX3CR1 increased in the cochlea upon neomycin treatment, and CX3CL1 was expressed on HCs, while CX3CR1 was expressed on MLCs. When cultured with 1 μg/mL exogenous CX3CL1, MLCs were activated by CX3CL1, and the cytokine level was increased in the cochleae leading to apoptosis in the HCs. In CX3CR1 knockout mice, a significantly greater number of cochlear HCs survived than in wild-type mice when the cochlear explants were cultured with neomycin in vitro. Furthermore, inhibiting the activation of MLCs with minocycline reduced the neomycin-induced HC loss and improved the hearing function in neomycin-treated mice in vivo. Our results demonstrate that CX3CL1-induced MLC activation plays an important role in the induction of HC death and provide evidence for CX3CL1 and CX3CR1 as promising new therapeutic targets for the prevention of hearing loss.
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Affiliation(s)
- Shan Sun
- Research Center, Affiliated Eye and ENT Hospital of Fudan University, Shanghai, China
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238
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Huth ME, Han KH, Sotoudeh K, Hsieh YJ, Effertz T, Vu AA, Verhoeven S, Hsieh MH, Greenhouse R, Cheng AG, Ricci AJ. Designer aminoglycosides prevent cochlear hair cell loss and hearing loss. J Clin Invest 2015; 125:583-92. [PMID: 25555219 DOI: 10.1172/jci77424] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 11/13/2014] [Indexed: 02/02/2023] Open
Abstract
Bacterial infections represent a rapidly growing challenge to human health. Aminoglycosides are widely used broad-spectrum antibiotics, but they inflict permanent hearing loss in up to ~50% of patients by causing selective sensory hair cell loss. Here, we hypothesized that reducing aminoglycoside entry into hair cells via mechanotransducer channels would reduce ototoxicity, and therefore we synthesized 9 aminoglycosides with modifications based on biophysical properties of the hair cell mechanotransducer channel and interactions between aminoglycosides and the bacterial ribosome. Compared with the parent aminoglycoside sisomicin, all 9 derivatives displayed no or reduced ototoxicity, with the lead compound N1MS 17 times less ototoxic and with reduced penetration of hair cell mechanotransducer channels in rat cochlear cultures. Both N1MS and sisomicin suppressed growth of E. coli and K. pneumoniae, with N1MS exhibiting superior activity against extended spectrum β lactamase producers, despite diminished activity against P. aeruginosa and S. aureus. Moreover, systemic sisomicin treatment of mice resulted in 75% to 85% hair cell loss and profound hearing loss, whereas N1MS treatment preserved both hair cells and hearing. Finally, in mice with E. coli-infected bladders, systemic N1MS treatment eliminated bacteria from urinary tract tissues and serially collected urine samples, without compromising auditory and kidney functions. Together, our findings establish N1MS as a nonototoxic aminoglycoside and support targeted modification as a promising approach to generating nonototoxic antibiotics.
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239
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Sills JM, Southall BL, Reichmuth C. Amphibious hearing in ringed seals (Pusa hispida): underwater audiograms, aerial audiograms and critical ratio measurements. J Exp Biol 2015; 218:2250-9. [DOI: 10.1242/jeb.120972] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/12/2015] [Indexed: 11/20/2022]
Abstract
Ringed seals are semi-aquatic marine mammals with a circumpolar Arctic distribution. In this study, we investigate the amphibious hearing capabilities of ringed seals to provide auditory profiles for this species across the full range of hearing. Using psychophysical methods with two trained ringed seals, detection thresholds for narrowband signals were measured under quiet, carefully controlled environmental conditions to generate aerial and underwater audiograms. Masked underwater thresholds were measured in the presence of octave-band noise to determine critical ratios. Results indicate that ringed seals possess hearing abilities comparable to those of spotted and harbor seals, and considerably better than previously reported for ringed and harp seals. Best sensitivity was 49 dB re 1 µPa (12.8 kHz) in water, and -12 dB re 20 µPa (4.5 kHz) in air, rivaling the acute hearing abilities of some fully aquatic and terrestrial species in their respective media. Critical ratio measurements ranged from 14 dB at 0.1 kHz to 31 dB at 25.6 kHz, suggesting that ringed seals—like other true seals—can efficiently extract signals from background noise across a broad range of frequencies. The work described herein extends similar research on amphibious hearing in spotted seals, the results of which were recently published in this journal [Sills et al., J. Exp. Biol., 217, 726-734 (2014)]. These parallel studies enhance our knowledge of the auditory capabilities of ice-living seals, and inform effective management strategies for these and related species in a rapidly changing Arctic environment.
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Affiliation(s)
- Jillian M. Sills
- Department of Ocean Sciences, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 USA
| | - Brandon L. Southall
- Long Marine Laboratory, Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95060 USA & SEA, Inc., 9099 Soquel Drive, Suite 8, Aptos, California 95003 USA
| | - Colleen Reichmuth
- Long Marine Laboratory, Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95060 USA
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240
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Liu Y, Yu Y, Chu H, Bing D, Wang S, Zhou L, Chen J, Chen Q, Pan C, Sun Y, Cui Y. 17-DMAG induces Hsp70 and protects the auditory hair cells from kanamycin ototoxicity in vitro. Neurosci Lett 2014; 588:72-7. [PMID: 25556684 DOI: 10.1016/j.neulet.2014.12.060] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/28/2014] [Accepted: 12/30/2014] [Indexed: 01/17/2023]
Abstract
Heat shock protein 70 (Hsp70) has been known to be able to play a protective role in the cochlea. The aim of this study was to investigate whether geldanamycin hydrosoluble derivative 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG) has the ability to induce Hsp70 up-regulation to protect hair cells from kanamycin-induced ototoxicity in vitro. The organ of Corti (OC) explants were isolated from mice at postnatal day 3-5. Then, the explants were exposed to kanamycin with or without pre-incubation with 17-DMAG. The expression of Hsp70 was assessed by reverse transcription-quantitative polymerase chain reaction, ELISA, and immunofluorescent staining. The surviving hair cells were examined by phalloidin labeling and were counted. We found that Hsp70 expression in the explants after pre-incubation with 17-DMAG was significantly increased at both mRNA and protein levels. Immunofluorescent staining showed that Hsp70 was mainly located in the auditory hair cells. Compared with kanamycin group, the loss of hair cells was inhibited significantly in 17-DMAG+kanamycin group. Our study demonstrated that 17-DMAG induces Hsp70 in the hair cells, and has a significant protective effect against kanamycin ototoxicity in vitro. 17-DMAG has the possibility to be a safe and effective anti-ototoxic drug.
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Affiliation(s)
- Yun Liu
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Yang Yu
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China.
| | - Hanqi Chu
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Dan Bing
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Shaoli Wang
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Liangqiang Zhou
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Jin Chen
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Qingguo Chen
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Chunchen Pan
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Yanbo Sun
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Yonghua Cui
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
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241
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Aminoglycoside stress together with the 12S rRNA 1494C>T mutation leads to mitophagy. PLoS One 2014; 9:e114650. [PMID: 25474306 PMCID: PMC4256443 DOI: 10.1371/journal.pone.0114650] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 11/12/2014] [Indexed: 12/16/2022] Open
Abstract
Aminoglycosides as modifying factors modulated the phenotypic manifestation of mitochondrial rRNA mutations and the incomplete penetrance of hearing loss. In this report, using cybrids harboring the m.1494C>T mutation, we showed that gentamycin aggravated mitochondrial dysfunction in a combination of the m.1494C>T mutation. The m.1494C>T mutation was responsible for the dramatic reduction in three mtDNA-encoded proteins of H-strand, with the average of 39% reduction, except of the MT-ND6 protein, accompanied with 21% reduction of ATP production and increase in mitochondrial reactive oxygen species, compared with those of control cybrids. After exposure to gentamycin, 35% reduction of mitochondrial ATP production was observed in mutant cybrids with a marked decrease of the mitochondrial membrane potential. More excessive cellular reactive oxygen species was detected with stimulus of gentamycin than those in mutant cells. Under gentamycin and m.1494C>T stress together, more dysfunctional mitochondria were forced to fuse and exhibited mitophagy via up-regulated LC3-B, as a compensatory protective response to try to optimize mitochondrial function, rather than undergo apoptosis. These findings may provide valuable information to further understand of mechanistic link between mitochondrial rRNA mutation, toxicity of AGs and hearing loss.
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242
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Population pharmacokinetics of gentamicin and dosing optimization for infants. Antimicrob Agents Chemother 2014; 59:482-9. [PMID: 25385111 DOI: 10.1128/aac.03464-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to characterize and validate the population pharmacokinetics of gentamicin in infants and to determine the influences of clinically relevant covariates to explain the inter- and intraindividual variabilities associated with this drug. Infants receiving intravenous gentamicin and with routine therapeutic drug monitoring were consecutively enrolled in the study. Plasma concentration and time data were retrospectively collected from 208 infants (1 to 24 months old) of the Hospital Universitario Severo Ochoa (Spain), of whom 44% were males (mean age [± standard deviation], 5.8 ± 4.8 months; mean body weight, 6.4 ± 2.2 kg). Data analysis was performed with NONMEM 7.2. One- and two-compartment open models were analyzed to estimate the gentamicin population parameters and the influences of several covariates. External validation was carried out in another population of 55 infants. The behavior of gentamicin in infants exhibits two-compartment pharmacokinetics, with total body weight being the covariate that mainly influences central volume (Vc) and clearance (CL); this parameter was also related to creatinine clearance. Both parameters are age related and different from those reported for neonatal populations. On the basis of clinical presentation and diagnosis, a once-daily dosage regimen of 7 mg/kg of body weight every 24 h is proposed for intravenous gentamicin, followed by therapeutic drug monitoring in order to avoid toxicity and ensure efficacy with minimal blood sampling. Gentamicin pharmacokinetics and disposition were accurately characterized in this pediatric population (infants), with the parameters obtained being different from those reported for neonates and children. These differences should be considered in the dosing and therapeutic monitoring of this antibiotic.
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Mattappalil A, Mergenhagen KA. Neurotoxicity with Antimicrobials in the Elderly: A Review. Clin Ther 2014; 36:1489-1511.e4. [DOI: 10.1016/j.clinthera.2014.09.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/24/2014] [Accepted: 09/17/2014] [Indexed: 02/07/2023]
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244
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Ayoob AM, Borenstein JT. The role of intracochlear drug delivery devices in the management of inner ear disease. Expert Opin Drug Deliv 2014; 12:465-79. [PMID: 25347140 DOI: 10.1517/17425247.2015.974548] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
INTRODUCTION Diseases of the inner ear include those of the auditory and vestibular systems, and frequently result in disabling hearing loss or vertigo. Despite a rapidly expanding pipeline of potential cochlear therapeutics, the inner ear remains a challenging organ for targeted drug delivery, and new technologies are required to deliver these therapies in a safe and efficacious manner. In addition to traditional approaches for direct inner ear drug delivery, novel microfluidics-based systems are under development, promising improved control over pharmacokinetics over longer periods of delivery, ultimately with application towards hair cell regeneration in humans. AREAS COVERED Advances in the development of intracochlear drug delivery systems are reviewed, including passive systems, active microfluidic technologies and cochlear prosthesis-mediated delivery. This article provides a description of novel delivery systems and their potential future clinical applications in treating inner ear disease. EXPERT OPINION Recent progresses in microfluidics and miniaturization technologies are enabling the development of wearable and ultimately implantable drug delivery microsystems. Progress in this field is being spurred by the convergence of advances in molecular biology, microfluidic flow control systems and models for drug transport in the inner ear. These advances will herald a new generation of devices, with near-term applications in preclinical models, and ultimately with human clinical use for a range of diseases of the inner ear.
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Neurotrophic and antioxidant effects of silymarin comparable to 4-methylcatechol in protection against gentamicin-induced ototoxicity in guinea pigs. Pharmacol Rep 2014; 67:317-25. [PMID: 25712657 DOI: 10.1016/j.pharep.2014.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 09/14/2014] [Accepted: 10/06/2014] [Indexed: 11/21/2022]
Abstract
BACKGROUND Despite that gentamicin is a very effective aminoglycoside, its potential ototoxicity which is of irreversible nature makes a challenge and limitation for its use. This study was designed to investigate possible neurotrophic and antioxidant effects of silymarin comparable to 4-methylcatechol in protection against gentamicin-induced ototoxicity. METHODS AND RESULTS Twenty pigmented guinea pigs were divided into four equal groups, where group I served as normal control group. The other groups received gentamicin (120 mg/kg/day, ip) for 19 days where group II given vehicle of 1% CMC, group III and group IV were pre-treated 2h before gentamicin by 4-methylcatechol (10 μg/kg, ip) and silymarin (100mg/kg, oral gavage), respectively. The main findings indicated that silymarin exhibited restoration of nerve growth factor (NGF) levels and increased tropomyosin-related kinase receptors-A (Trk-A) m-RNA expression in cochlear tissue and preservation of hair cells of organ of Corti by scanning electron microscopy (SEM) with significant decrease in auditory brainstem response (ABR) threshold compared to 4-methylcatechol. Only silymarin caused significant amelioration in oxidative stress state by reducing malondialdehyde (MDA) levels and increasing catalase activity. CONCLUSIONS Silymarin exerts superiority over 4-methylcatechol when recommended as protective agent against gentamicin ototoxicity based on its efficient neurotrophic and antioxidant activities.
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Abstract
PURPOSE OF THE REVIEW This article presents research findings from two invertebrate model systems with potential to advance both the understanding of noise-induced hearing loss mechanisms and the development of putative therapies to reduce human noise damage. RECENT FINDINGS Work on sea anemone hair bundles, which resemble auditory hair cells, has revealed secretions that exhibit astonishing healing properties not only for damaged hair bundles, but also for vertebrate lateral line neuromasts. We present progress on identifying functional components of the secretions, and their mechanisms of repair. The second model, the Johnston's organ in Drosophila, is also genetically homologous to hair cells and shows noise-induced hearing loss similar to vertebrates. Drosophila offers genetic and molecular insight into noise sensitivity and pathways that can be manipulated to reduce stress and damage from noise. SUMMARY Using the comparative approach is a productive avenue to understanding basic mechanisms, in this case cellular responses to noise trauma. Expanding study of these systems may accelerate identification of strategies to reduce or prevent noise damage in the human ear.
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Affiliation(s)
- Kevin W Christie
- Department of Biology, The University of Iowa, Iowa City, Iowa 52246
| | - Daniel F. Eberl
- Department of Biology, The University of Iowa, Iowa City, Iowa 52246
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Figueroa VA, Retamal MA, Cea LA, Salas JD, Vargas AA, Verdugo CA, Jara O, Martínez AD, Sáez JC. Extracellular gentamicin reduces the activity of connexin hemichannels and interferes with purinergic Ca(2+) signaling in HeLa cells. Front Cell Neurosci 2014; 8:265. [PMID: 25237294 PMCID: PMC4154469 DOI: 10.3389/fncel.2014.00265] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 08/18/2014] [Indexed: 01/15/2023] Open
Abstract
Gap junction channels (GJCs) and hemichannels (HCs) are composed of protein subunits termed connexins (Cxs) and are permeable to ions and small molecules. In most organs, GJCs communicate the cytoplasm of adjacent cells, while HCs communicate the intra and extracellular compartments. In this way, both channel types coordinate physiological responses of cell communities. Cx mutations explain several genetic diseases, including about 50% of autosomal recessive non-syndromic hearing loss. However, the possible involvement of Cxs in the etiology of acquired hearing loss remains virtually unknown. Factors that induce post-lingual hearing loss are diverse, exposure to gentamicin an aminoglycoside antibiotic, being the most common. Gentamicin has been proposed to block GJCs, but its effect on HCs remains unknown. In this work, the effect of gentamicin on the functional state of HCs was studied and its effect on GJCs was reevaluated in HeLa cells stably transfected with Cxs. We focused on Cx26 because it is the main Cx expressed in the cochlea of mammals where it participates in purinergic signaling pathways. We found that gentamicin applied extracellularly reduces the activity of HCs, while dye transfer across GJCs was not affected. HCs were also blocked by streptomycin, another aminoglycoside antibiotic. Gentamicin also reduced the adenosine triphosphate release and the HC-dependent oscillations of cytosolic free-Ca2+ signal. Moreover, gentamicin drastically reduced the Cx26 HC-mediated membrane currents in Xenopus laevis oocytes. Therefore, the extracellular gentamicin-induced inhibition of Cx HCs may adversely affect autocrine and paracrine signaling, including the purinergic one, which might partially explain its ototoxic effects.
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Affiliation(s)
- Vania A Figueroa
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile ; Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Mauricio A Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Luis A Cea
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile
| | - José D Salas
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Aníbal A Vargas
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Christian A Verdugo
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Oscar Jara
- Instituto Milenio, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Agustín D Martínez
- Instituto Milenio, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile ; Instituto Milenio, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
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Affiliation(s)
- Schellack Natalie
- Department of Pharmacy, Faculty of Health Sciences, University of Limpopo (Medunsa Campus)
| | - Naude Alida
- Department of Pharmacy, Faculty of Health Sciences, University of Limpopo (Medunsa Campus)
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Park MK, Im GJ, Chang J, Chae SW, Yoo J, Han WG, Hwang GH, Jung JY, Choi J, Jung HH, Chung AY, Park HC, Choi J. Protective effects of caffeic acid phenethyl ester (CAPE) against neomycin-induced hair cell damage in zebrafish. Int J Pediatr Otorhinolaryngol 2014; 78:1311-5. [PMID: 24880922 DOI: 10.1016/j.ijporl.2014.05.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 05/12/2014] [Accepted: 05/14/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Caffeic acid phenethyl ester (CAPE) is known to reduce the generation of oxygen-derived free radicals, which is a major mechanism of aminoglycoside-induced ototoxicity. The objective of the present study was to evaluate the effects of CAPE on neomycin-induced ototoxicity in zebrafish (Brn3c: EGFP). METHODS Five-day post-fertilization zebrafish larvae (n=10) were exposed to 125 μM neomycin and one of the following CAPE concentrations for 1h: 50, 100, 250, 500, or 1000 μM. Ultrastructural changes were evaluated using scanning electron microscopy (SEM). The terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL) assay and 2-[4-(dimethylamino)styryl]-N-ethylpyridiniumiodide (DASPEI) assay were performed for evaluation of apoptosis and mitochondrial damage. RESULTS CAPE decreased neomycin-induced hair cell loss in the neuromasts (500 μM CAPE: 12.7 ± 1.1 cells, 125 μM neomycin only: 6.3 ± 1.1 cells; n = 10, P < 0.05). In the ultrastructural analysis, structures of mitochondria and hair cells were preserved when exposed to 125 μM neomycin and 500 μM CAPE. CAPE decreased apoptosis and mitochondrial damage. CONCLUSION In the present study, CAPE attenuated neomycin-induced hair cell damage in zebrafish. The results of the current study suggest that neomycin induces apoptosis, and the apoptotic cell death can be prevented by treatment with CAPE in zebrafish.
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Affiliation(s)
- Moo Kyun Park
- Department of Otolaryngology - Head and Neck Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Gi Jung Im
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Jiwon Chang
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Sung Won Chae
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Jun Yoo
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Won-gue Han
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Gyu Ho Hwang
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Jong Yoon Jung
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Jungim Choi
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Hak Hyun Jung
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Ah-Young Chung
- Laboratory of Neurodevelopmental Genetics, Graduate School of Medicine, Korea University, Ansan-City, South Korea
| | - Hae-Chul Park
- Laboratory of Neurodevelopmental Genetics, Graduate School of Medicine, Korea University, Ansan-City, South Korea
| | - June Choi
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea.
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Scharr AL, Mooney TA, Schweizer FE, Ketten DR. Aminoglycoside-induced damage in the statocyst of the longfin inshore squid, Doryteuthis pealeii. THE BIOLOGICAL BULLETIN 2014; 227:51-60. [PMID: 25216502 DOI: 10.1086/bblv227n1p51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Squid are a significant component of the marine biomass and are a long-established model organism in experimental neurophysiology. The squid statocyst senses linear and angular acceleration and is the best candidate for mediating squid auditory responses, but its physiology and morphology are rarely studied. The statocyst contains mechano-sensitive hair cells that resemble hair cells in the vestibular and auditory systems of other animals. We examined whether squid statocyst hair cells are sensitive to aminoglycosides, a group of antibiotics that are ototoxic in fish, birds, and mammals. To assess aminoglycoside-induced damage, we used immunofluorescent methods to image the major cell types in the statocyst of longfin squid (Doryteuthis pealeii). Statocysts of live, anesthetized squid were injected with either a buffered saline solution or neomycin at concentrations ranging from 0.05 to 3.0 mmol l(-1). The statocyst hair cells of the macula statica princeps were examined 5 h post-treatment. Anti-acetylated tubulin staining showed no morphological differences between the hair cells of saline-injected and non-injected statocysts. The hair cell bundles of the macula statica princeps in aminoglycoside-injected statocysts were either missing or damaged, with the amount of damage being dose-dependent. The proportion of missing hair cells did not increase at the same rate as damaged cells, suggesting that neomycin treatment affects hair cells in a nonlethal manner. These experiments provide a reliable method for imaging squid hair cells. Further, aminoglycosides can be used to induce hair cell damage in a primary sensory area of the statocyst of squid. Such results support further studies on loss of hearing and balance in squid.
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Affiliation(s)
- Alexandra L Scharr
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; Stanford University School of Medicine, Palo Alto, California 94305;
| | - T Aran Mooney
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543
| | - Felix E Schweizer
- Marine Biological Laboratory, Woods Hole, Massachusetts 02543; Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California 90095
| | - Darlene R Ketten
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; Harvard Medical School, Boston, Massachusetts 02114; and Curtin University, Perth, Western Australia 6845, Australia
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