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Lee DS, Schrader A, Zou J, Ang WH, Warchol M, Sheets L. Cisplatin drives mitochondrial dysregulation in sensory hair cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.29.577846. [PMID: 38352581 PMCID: PMC10862698 DOI: 10.1101/2024.01.29.577846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2024]
Abstract
Cisplatin is a chemotherapy drug that causes permanent hearing loss by injuring cochlear hair cells. The mechanisms that initiate injury are not fully understood, but mitochondria have emerged as potential mediators of hair cell cytotoxicity. Using in vivo live imaging of hair cells in the zebrafish lateral-line organ expressing a genetically encoded indicator of cumulative mitochondrial activity, we first demonstrate that greater redox history increases susceptibility to cisplatin. Next, we conducted time-lapse imaging to understand dynamic changes in mitochondrial homeostasis and observe elevated mitochondrial and cytosolic calcium that surge prior to hair cell death. Furthermore, using a localized probe that fluoresces in the presence of cisplatin, we show that cisplatin directly accumulates in hair cell mitochondria, and this accumulation occurs before mitochondrial dysregulation and apoptosis. Our findings provide evidence that cisplatin directly targets hair cell mitochondria and support that the mitochondria are integral to cisplatin cytotoxicity in hair cells.
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Liu Z, Zhang H, Hong G, Bi X, Hu J, Zhang T, An Y, Guo N, Dong F, Xiao Y, Li W, Zhao X, Chu B, Guo S, Zhang X, Chai R, Fu X. Inhibition of Gpx4-mediated ferroptosis alleviates cisplatin-induced hearing loss in C57BL/6 mice. Mol Ther 2024; 32:1387-1406. [PMID: 38414247 PMCID: PMC11081921 DOI: 10.1016/j.ymthe.2024.02.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/29/2024] [Accepted: 02/24/2024] [Indexed: 02/29/2024] Open
Abstract
Cisplatin-induced hearing loss is a common side effect of cancer chemotherapy in clinics; however, the mechanism of cisplatin-induced ototoxicity is still not completely clarified. Cisplatin-induced ototoxicity is mainly associated with the production of reactive oxygen species, activation of apoptosis, and accumulation of intracellular lipid peroxidation, which also is involved in ferroptosis induction. In this study, the expression of TfR1, a ferroptosis biomarker, was upregulated in the outer hair cells of cisplatin-treated mice. Moreover, several key ferroptosis regulator genes were altered in cisplatin-damaged cochlear explants based on RNA sequencing, implying the induction of ferroptosis. Ferroptosis-related Gpx4 and Fsp1 knockout mice were established to investigate the specific mechanisms associated with ferroptosis in cochleae. Severe outer hair cell loss and progressive damage of synapses in inner hair cells were observed in Atoh1-Gpx4-/- mice. However, Fsp1-/- mice showed no significant hearing phenotype, demonstrating that Gpx4, but not Fsp1, may play an important role in the functional maintenance of HCs. Moreover, findings showed that FDA-approved luteolin could specifically inhibit ferroptosis and alleviate cisplatin-induced ototoxicity through decreased expression of transferrin and intracellular concentration of ferrous ions. This study indicated that ferroptosis inhibition through the reduction of intracellular ferrous ions might be a potential strategy to prevent cisplatin-induced hearing loss.
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MESH Headings
- Animals
- Cisplatin/adverse effects
- Ferroptosis/drug effects
- Ferroptosis/genetics
- Mice
- Hearing Loss/chemically induced
- Hearing Loss/genetics
- Hearing Loss/metabolism
- Mice, Knockout
- Phospholipid Hydroperoxide Glutathione Peroxidase/metabolism
- Phospholipid Hydroperoxide Glutathione Peroxidase/genetics
- Mice, Inbred C57BL
- Disease Models, Animal
- Receptors, Transferrin/metabolism
- Receptors, Transferrin/genetics
- Reactive Oxygen Species/metabolism
- Lipid Peroxidation/drug effects
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/drug effects
- Hair Cells, Auditory, Outer/pathology
- Ototoxicity/etiology
- Ototoxicity/metabolism
- Antineoplastic Agents/adverse effects
- Apoptosis/drug effects
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Affiliation(s)
- Ziyi Liu
- Medical Science and Technology Innovation Center, Institute of Brain Science and Brain-inspired Research, Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Hanbing Zhang
- Department of Otorhinolaryngology, Qilu Hospital of Shandong University, NHC Key Laboratory of Otorhinolaryngology (Shandong University), Jinan, Shandong 250012, China
| | - Guodong Hong
- Medical Science and Technology Innovation Center, Institute of Brain Science and Brain-inspired Research, Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Xiuli Bi
- Medical Science and Technology Innovation Center, Institute of Brain Science and Brain-inspired Research, Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Jun Hu
- Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Tiancheng Zhang
- Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Yachun An
- School of Life Science, Shandong University, Qingdao, Shandong 266237, China
| | - Na Guo
- Medical Science and Technology Innovation Center, Institute of Brain Science and Brain-inspired Research, Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Fengyue Dong
- School of Life Science, Shandong University, Qingdao, Shandong 266237, China
| | - Yu Xiao
- School of Life Science, Shandong University, Qingdao, Shandong 266237, China
| | - Wen Li
- Medical Science and Technology Innovation Center, Institute of Brain Science and Brain-inspired Research, Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Xiaoxu Zhao
- Medical Science and Technology Innovation Center, Institute of Brain Science and Brain-inspired Research, Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Bo Chu
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250102, China
| | - Siwei Guo
- School of Life Science, Shandong University, Qingdao, Shandong 266237, China
| | - Xiaohan Zhang
- Medical Science and Technology Innovation Center, Institute of Brain Science and Brain-inspired Research, Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Renjie Chai
- Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, China; State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, Jiangsu 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China; Department of Neurology, Aerospace Center Hospital, School of Life Science, Beijing Institute of Technology, Beijing 100081, China; Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China; Southeast University Shenzhen Research Institute, Shenzhen, Guangdong 518063, China.
| | - Xiaolong Fu
- Medical Science and Technology Innovation Center, Institute of Brain Science and Brain-inspired Research, Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China.
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3
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Hoogstraten CA, Koenderink JB, van Straaten CE, Scheer-Weijers T, Smeitink JAM, Schirris TJJ, Russel FGM. Pyruvate dehydrogenase is a potential mitochondrial off-target for gentamicin based on in silico predictions and in vitro inhibition studies. Toxicol In Vitro 2024; 95:105740. [PMID: 38036072 DOI: 10.1016/j.tiv.2023.105740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 11/08/2023] [Accepted: 11/22/2023] [Indexed: 12/02/2023]
Abstract
During the drug development process, organ toxicity leads to an estimated failure of one-third of novel chemical entities. Drug-induced toxicity is increasingly associated with mitochondrial dysfunction, but identifying the underlying molecular mechanisms remains a challenge. Computational modeling techniques have proven to be a good tool in searching for drug off-targets. Here, we aimed to identify mitochondrial off-targets of the nephrotoxic drugs tenofovir and gentamicin using different in silico approaches (KRIPO, ProBis and PDID). Dihydroorotate dehydrogenase (DHODH) and pyruvate dehydrogenase (PDH) were predicted as potential novel off-target sites for tenofovir and gentamicin, respectively. The predicted targets were evaluated in vitro, using (colorimetric) enzymatic activity measurements. Tenofovir did not inhibit DHODH activity, while gentamicin potently reduced PDH activity. In conclusion, the use of in silico methods appeared a valuable approach in predicting PDH as a mitochondrial off-target of gentamicin. Further research is required to investigate the contribution of PDH inhibition to overall renal toxicity of gentamicin.
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Affiliation(s)
- Charlotte A Hoogstraten
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands; Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands
| | - Jan B Koenderink
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands
| | - Carolijn E van Straaten
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands
| | - Tom Scheer-Weijers
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands
| | - Jan A M Smeitink
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands; Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands; Khondrion BV, Nijmegen 6525 EX, the Netherlands
| | - Tom J J Schirris
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands; Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands
| | - Frans G M Russel
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands; Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands.
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4
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Du P, Liu T, Luo P, Li H, Tang W, Zong S, Xiao H. SIRT3/GLUT4 signaling activation by metformin protect against cisplatin-induced ototoxicity in vitro. Arch Toxicol 2023; 97:1147-1162. [PMID: 36800006 DOI: 10.1007/s00204-023-03457-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 02/02/2023] [Indexed: 02/18/2023]
Abstract
Cisplatin is highly effective for killing tumor cells. However, as one of its side effects, ototoxicity limits the clinical application of cisplatin. The mechanisms of cisplatin-induced ototoxicity have not been fully clarified yet. SIRT3 is a deacetylated protein mainly located in mitochondria, which regulates a variety of physiological processes in cells. The role of SIRT3 in cisplatin-induced hair cell injury has not been founded. In this study, primary cultured cochlear explants exposed to 5 μM cisplatin, as well as OC-1 cells exposed to 10 μM cisplatin, were used to establish models of cisplatin-induced ototoxicity in vitro. We found that when combined with cisplatin, metformin (75 μM) significantly up-regulated the expression of SIRT3 and alleviated cisplatin-induced apoptosis of hair cells. We regulated the expression of SIRT3 to explore the role of SIRT3 in cisplatin-induced auditory hair cell injury. Overexpression of SIRT3 promoted the survival of auditory hair cells and alleviated the apoptosis of auditory hair cells. In contrast, knockdown of SIRT3 impaired the protective effect of metformin and exacerbated cisplatin injury. In addition, we found that the protective effect of SIRT3 may be achieved by regulating GLUT4 translocation and rescuing impaired glucose uptake caused by cisplatin. Our study confirmed that upregulation of SIRT3 may antagonize cisplatin-induced ototoxicity, and provided a new perspective for the study of cisplatin-induced ototoxicity.
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Affiliation(s)
- Peiyu Du
- Department of Otolaryngology-Head and Neck Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Tianyi Liu
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Pan Luo
- Department of Otolaryngology-Head and Neck Surgery, Wuhan Central Hospital, Wuhan, China
| | - Hejie Li
- Department of Otolaryngology-Head and Neck Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Wei Tang
- Department of Otolaryngology-Head and Neck Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Shimin Zong
- Department of Otolaryngology-Head and Neck Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Hongjun Xiao
- Department of Otolaryngology-Head and Neck Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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5
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O'Sullivan JDB, Bullen A, Mann ZF. Mitochondrial form and function in hair cells. Hear Res 2023; 428:108660. [PMID: 36525891 DOI: 10.1016/j.heares.2022.108660] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/07/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022]
Abstract
Hair cells (HCs) are specialised sensory receptors residing in the neurosensory epithelia of inner ear sense organs. The precise morphological and physiological properties of HCs allow us to perceive sound and interact with the world around us. Mitochondria play a significant role in normal HC function and are also intricately involved in HC death. They generate ATP essential for sustaining the activity of ion pumps, Ca2+ transporters and the integrity of the stereociliary bundle during transduction as well as regulating cytosolic calcium homoeostasis during synaptic transmission. Advances in imaging techniques have allowed us to study mitochondrial populations throughout the HC, and how they interact with other organelles. These analyses have identified distinct mitochondrial populations between the apical and basolateral portions of the HC, in which mitochondrial morphology appears determined by the physiological processes in the different cellular compartments. Studies in HCs across species show that ototoxic agents, ageing and noise damage directly impact mitochondrial structure and function resulting in HC death. Deciphering the molecular mechanisms underlying this mitochondrial sensitivity, and how their morphology relates to their function during HC death, requires that we first understand this relationship in the context of normal HC function.
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Affiliation(s)
- James D B O'Sullivan
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral, Craniofacial Sciences, King's College London, London SE1 9RT, U.K
| | - Anwen Bullen
- UCL Ear Institute, University College London, London WC1×8EE, U.K.
| | - Zoë F Mann
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral, Craniofacial Sciences, King's College London, London SE1 9RT, U.K.
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6
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Lysakowski A, Govindaraju AC, Raphael RM. Structural and functional diversity of mitochondria in vestibular/cochlear hair cells and vestibular calyx afferents. Hear Res 2022; 426:108612. [PMID: 36223702 DOI: 10.1016/j.heares.2022.108612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 07/21/2022] [Accepted: 09/19/2022] [Indexed: 11/30/2022]
Abstract
Mitochondria supply energy in the form of ATP to drive a plethora of cellular processes. In heart and liver cells, mitochondria occupy over 20% of the cellular volume and the major need for ATP is easily identifiable - i.e., to drive cross-bridge recycling in cardiac cells or biosynthetic machinery in liver cells. In vestibular and cochlear hair cells the overall cellular mitochondrial volume is much less, and mitochondria structure varies dramatically in different regions of the cell. The regional demands for ATP and cellular forces that govern mitochondrial structure and localization are not well understood. Below we review our current understanding of the heterogeneity of form and function in hair cell mitochondria. A particular focus of this review will be on regional specialization in vestibular hair cells, where large mitochondria are found beneath the cuticular plate in close association with the striated organelle. Recent findings on the role of mitochondria in hair cell death and aging are covered along with potential therapeutic approaches. Potential avenues for future research are discussed, including the need for integrated computational modeling of mitochondrial function in hair cells and the vestibular afferent calyx.
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Affiliation(s)
- Anna Lysakowski
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, 808 S. Wood St., M/C 512, Chicago, IL 60605, USA.
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Tao L, Segil N. CDK2 regulates aminoglycoside-induced hair cell death through modulating c-Jun activity: Inhibiting CDK2 to preserve hearing. Front Mol Neurosci 2022; 15:1013383. [PMID: 36311033 PMCID: PMC9606710 DOI: 10.3389/fnmol.2022.1013383] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 09/27/2022] [Indexed: 11/13/2022] Open
Abstract
Sensory hair cell death caused by the ototoxic side effects of many clinically used drugs leads to permanent sensorineural hearing loss in patients. Aminoglycoside antibiotics are widely used and well-known for their ototoxicity, but the molecular mechanisms of aminoglycoside-induced hair cell death are not well understood. This creates challenges in our attempts to alleviate or prevent such adverse side effects. Here, we report a regulatory role of CDK2 in aminoglycoside-induced hair cell death. Utilizing organotypic cultures of cochleae from neonatal mice, we show that blocking CDK2 activity by either pharmaceutical inhibition or by Cdk2 gene knockout protects hair cells against the ototoxicity of gentamicin—one of the most commonly used aminoglycoside antibiotics—by interfering with intrinsic programmed cell death processes. Specifically, we show that CDK2 inhibition delays the collapse of mitochondria and the activation of a caspase cascade. Furthermore, at the molecular level, inhibition of CDK2 activity influences proapoptotic JNK signaling by reducing the protein level of c-Jun and suppressing the gentamicin-induced upregulation of c-Jun target genes Jun and Bim. Our in vivo studies reveal that Cdk2 gene knockout animals are significantly less sensitive to gentamicin ototoxicity compared to wild-type littermates. Altogether, our work ascertains the non-cell cycle role of CDK2 in regulating aminoglycoside-induced hair cell apoptosis and sheds lights on new potential strategies for hearing protection against ototoxicity.
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Affiliation(s)
- Litao Tao
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
- USC Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
- *Correspondence: Litao Tao,
| | - Neil Segil
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
- USC Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
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Gibaja A, Alvarado JC, Scheper V, Carles L, Juiz JM. Kanamycin and Cisplatin Ototoxicity: Differences in Patterns of Oxidative Stress, Antioxidant Enzyme Expression and Hair Cell Loss in the Cochlea. Antioxidants (Basel) 2022; 11:antiox11091759. [PMID: 36139833 PMCID: PMC9495324 DOI: 10.3390/antiox11091759] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/25/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
Kanamycin and cisplatin are ototoxic drugs. The mechanisms are incompletely known. With subcutaneous kanamycin (400 mg/kg, 15 days), auditory threshold shifts were detected at days 12–13 at 16 and 32 kHz, extending to 8 and 4 kHz at days 14–15. The outer hair cell (OHC) loss was concentrated past day 12. The maximum cochlear length showing apoptotic cells, tested with TUNEL, was at day 13. At day 15, 1/5 of the apical cochlea contained preserved OHCs. 3-nitrotyrosine (3-NT) immunolabeling, showing oxidative stress, was found in surviving OHCs and in basal and middle portions of the stria vascularis (SV). The antioxidant Gpx1 gene expression was decreased. The immunocytochemistry showed diminished Gpx1 in OHCs. With intraperitoneal cisplatin (16 mg/kg, single injection), no evoked auditory activity was recorded at the end of treatment, at 72 h. The basal third of the cochlea lacked OHCs. Apoptosis occupied the adjacent 1/3, and the apical third contained preserved OHCs. 3-NT immunolabeling was extensive in OHCs and the SV. Gpx1 and Sod1 gene expression was downregulated. Gpx1 immunostaining diminished in middle and basal SV. More OHCs survived cisplatin than kanamycin towards the apex, despite undetectable evoked activity. Differential regulation of antioxidant enzyme levels suggests differences in the antioxidant response for both drugs.
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Affiliation(s)
- Alejandro Gibaja
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008 Albacete, Spain
| | - Juan C. Alvarado
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008 Albacete, Spain
| | - Verena Scheper
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” of the German Research Foundation, DFG, MHH, 30625 Hannover, Germany
| | - Liliana Carles
- Department of Otolaryngology, University Hospital “Doce de Octubre”, 28041 Madrid, Spain
| | - José M. Juiz
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008 Albacete, Spain
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” of the German Research Foundation, DFG, MHH, 30625 Hannover, Germany
- IDINE/Med School, UCLM-Campus in Albacete, C/Almansa 14, 02008 Albacete, Spain
- Correspondence:
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Kishimoto-Urata M, Urata S, Fujimoto C, Yamasoba T. Role of Oxidative Stress and Antioxidants in Acquired Inner Ear Disorders. Antioxidants (Basel) 2022; 11:1469. [PMID: 36009187 PMCID: PMC9405327 DOI: 10.3390/antiox11081469] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/25/2022] [Accepted: 07/25/2022] [Indexed: 01/27/2023] Open
Abstract
Oxygen metabolism in the mitochondria is essential for biological activity, and reactive oxygen species (ROS) are produced simultaneously in the cell. Once an imbalance between ROS production and degradation (oxidative stress) occurs, cells are damaged. Sensory organs, especially those for hearing, are constantly exposed during daily life. Therefore, almost all mammalian species are liable to hearing loss depending on their environment. In the auditory pathway, hair cells, spiral ganglion cells, and the stria vascularis, where mitochondria are abundant, are the main targets of ROS. Excessive generation of ROS in auditory sensory organs is widely known to cause sensorineural hearing loss, and mitochondria-targeted antioxidants are candidates for treatment. This review focuses on the relationship between acquired hearing loss and antioxidant use to provide an overview of novel antioxidants, namely medicines, supplemental nutrients, and natural foods, based on clinical, animal, and cultured-cell studies.
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Affiliation(s)
| | | | | | - Tatsuya Yamasoba
- Department of Otolaryngology, Graduate School of Medicine, The University of Tokyo, Tokyo 1138655, Japan; (M.K.-U.); (S.U.); (C.F.)
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10
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A reduced form of nicotinamide riboside protects the cochlea against aminoglycoside-induced ototoxicity by SIRT1 activation. Biomed Pharmacother 2022; 150:113071. [PMID: 35658237 DOI: 10.1016/j.biopha.2022.113071] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/25/2022] [Accepted: 04/29/2022] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Nicotinamide adenine dinucleotide (NAD+), a coenzyme that plays crucial roles in many cellular processes, is a potential therapeutic target for various diseases. Dihydronicotinamide riboside (NRH), a novel reduced form of nicotinamide riboside, has emerged as a potent NAD+ precursor. Here, we studied the protective effects and underlying mechanism of NRH on aminoglycoside-induced ototoxicity. METHODS Auditory function and hair-cell (HC) morphology were examined to assess the effects of NRH on kanamycin-induced hearing loss. The pharmacokinetic parameters of NRH were measured in plasma and the cochlea using liquid chromatography tandem mass spectrometry. NAD+ levels in organ explant cultures were assessed to compare NRH with known NAD+ precursors. Immunofluorescence analysis was performed to detect reactive oxygen species (ROS) and apoptosis. We analyzed SIRT1 and 14-3-3 protein expression. EX527 and resveratrol were used to investigate the role of SIRT1 in the protective effect of NRH against kanamycin-induced ototoxicity. RESULTS NRH alleviated kanamycin-induced HC damage and attenuated hearing loss in mice. NRH reduced gentamicin-induced vestibular HC loss. Compared with NAD and NR, NRH produced more NAD+ in cochlear HCs and significantly ameliorated kanamycin-induced oxidative stress and apoptosis. NRH rescued the aminoglycoside-induced decreases in SIRT1 and 14-3-3 protein expression. Moreover, EX527 antagonized the protective effect of NRH on kanamycin-induced HC loss by inhibition of SIRT1, while resveratrol alleviated HC damage caused by EX527. CONCLUSIONS NRH ameliorates aminoglycoside-induced ototoxicity by inhibiting HC apoptosis by activating SIRT1 and decreasing ROS. NRH is an effective therapeutic option for aminoglycoside-induced ototoxicity.
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11
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Manohar S, Ding D, Jiang H, Li L, Chen GD, Kador P, Salvi R. Combined antioxidants and anti-inflammatory therapies fail to attenuate the early and late phases of cyclodextrin-induced cochlear damage and hearing loss. Hear Res 2021; 414:108409. [PMID: 34953289 DOI: 10.1016/j.heares.2021.108409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/08/2021] [Accepted: 12/06/2021] [Indexed: 11/04/2022]
Abstract
Niemann-Pick C1 (NPC1) is a fatal neurodegenerative disease caused by aberrant cholesterol metabolism. The progression of the disease can be slowed by removing excess cholesterol with high-doses of 2-hyroxypropyl-beta-cyclodextrin (HPβCD). Unfortunately, HPβCD causes hearing loss; the initial first phase involves a rapid destruction of outer hair cells (OHCs) while the second phase, occurring 4-6 weeks later, involves the destruction of inner hair cells (IHCs), pillar cells, collapse of the organ of Corti and spiral ganglion neuron degeneration. To determine whether the first and/or second phase of HPβCD-induced cochlear damage is linked, in part, to excess oxidative stress or neuroinflammation, rats were treated with a single-dose of 3000 mg/kg HPβCD alone or together with one of two combination therapies. Each combination therapy was administered from 2-days before to 6-weeks after the HPβCD treatment. Combination 1 consisted of minocycline, an antibiotic that suppresses neuroinflammation, and HK-2, a multifunctional redox modulator that suppresses oxidative stress. Combination 2 was comprised of minocycline plus N-acetyl cysteine (NAC), which upregulates glutathione, a potent antioxidant. To determine if either combination therapy could prevent HPβCD-induced hearing impairment and cochlear damage, distortion product otoacoustic emissions (DPOAE) were measured to assess OHC function and the cochlear compound action potential (CAP) was measured to assess the function of IHCs and auditory nerve fibers. Cochleograms were prepared to quantify the amount of OHC, IHC and pillar cell (PC) loss. HPβCD significantly reduced DPOAE and CAP amplitudes and caused significant OHC, IHC and OPC losses with losses greater in the high-frequency base of the cochlea than the apex. Neither minocycline + HK-2 (MIN+ HK-2) nor minocycline + NAC (MIN+NAC) prevented the loss of DPOAEs, CAPs, OHCs, IHCs or IPCs caused by HPβCD. These results suggest that oxidative stress and neuroinflammation are unlikely to play major roles in mediating the first or second phase of HPβCD-induced cochlear damage. Thus, HPβCD-induced ototoxicity must be mediated by some other unknown cell-death pathway possibly involving loss of trophic support from damaged support cells or disrupted cholesterol metabolism.
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Affiliation(s)
- Senthilvelan Manohar
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Haiyan Jiang
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Li Li
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Guang-Di Chen
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Peter Kador
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA.
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12
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Effect of Dexamethasone Combination with Gentamicin in Chemical Labyrinthectomy on Hearing Preservation and Vertigo Control in Patients with Unilateral Meniere's Disease: A Randomized Controlled Clinical Trial. J Clin Med 2021; 10:jcm10235581. [PMID: 34884281 PMCID: PMC8658607 DOI: 10.3390/jcm10235581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/22/2021] [Accepted: 11/25/2021] [Indexed: 12/03/2022] Open
Abstract
Chemical labyrinthectomy using gentamicin is a popular method for treating intractable vertigo attacks in Meniere’s disease. However, the risk of hearing loss remains a major concern for clinicians. We investigated the effect of simultaneous dexamethasone and gentamicin application on hearing preservation and vertigo control in patients with intractable unilateral Meniere’s disease. A single-institutional, prospective, single-blinded, randomized clinical trial was conducted. Gentamicin-soaked Gelfoam® was directly applied on the oval window following middle ear exploration. On the round window, dexamethasone-soaked Gelfoam® was applied in the gentamicin with dexamethasone group (GD group, n = 18), and saline-soaked Gelfoam® was applied in the gentamicin with sham reagent group (GO group, n = 19). The hearing change 8 weeks after the procedure and vertigo control 2–12 months after the procedure were investigated. The high-frequency hearing threshold was significantly increased in the GO group (p = 0.005 and 0.012 for 4 and 8 kHz, respectively), but not in the GD group. The short-term (2–6 months) vertigo control was more successful in the GD group (57.89% vs. 94.44%, p = 0.019), but long-term control (6–12 months) was insignificant. In conclusion, the combined application of gentamicin and dexamethasone in chemical labyrinthectomy is an effective method for protecting high-frequency hearing and vertigo control.
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13
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Cakir U, Tayman C. Relationship between gentamicin administration and ductal patency in very low birth weight infants. Curr Rev Clin Exp Pharmacol 2021; 17:149-155. [DOI: 10.2174/1574884716666210603110412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/08/2021] [Accepted: 04/07/2021] [Indexed: 11/22/2022]
Abstract
Background:
Patent ductus arteriosus (PDA) is associated with adverse clinical outcomes in very low birth weight (<1500g) infants.
Objective:
In our study, it was aimed to investigate the effect of gentamicin treatment, which is frequently used for early-onset sepsis on ductal patency.
Method:
We performed a single-center retrospective review of charts of preterm infants <32 weeks gestation with birth weight <1500 grams born between June 1, 2015, and December 31, 2019, at the neonatal intensive care unit. All infants underwent an echocardiogram (ECHO) at 72 hours. To determine the effect of gentamicin treatment on hemodynamically significant PDA (hsPDA), we compared the frequency and duration of gentamicin administration between infants with hsPDA and without hsPDA.
Results:
During the study period, 792 patients were evaluated. Gentamicin was given to more infants with hsPDA than to those without hsPDA (89.2 % vs. 64.6 %, p<0.001), and the duration of therapy was longer in those infants with hsPDA (7 days vs. 9 days, p<0.001). The area under the curve for duration of gentamicin was 0.772 (%95 CI: 0.742-0.804, P=0.0001), sensitivity: 59 (%95 CI: 53-65), specificity: 82 (%95 CI: 78-88), with a cut-off day for duration of gentamicin >7 days.
Conclusion:
In our study, it was found that ductal contraction decreased and hsPDA rate increased as the rate and duration of gentamicin increased.
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Affiliation(s)
- Ufuk Cakir
- Division of Neonatology, Department of Pediatrics, Health Sciences University, Ankara Bilkent City Hospital, Ankara, Turkey
| | - Cuneyt Tayman
- Division of Neonatology, Department of Pediatrics, Health Sciences University, Ankara Bilkent City Hospital, Ankara, Turkey
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14
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Abstract
Mitochondrial dysfunction has been suggested to be a risk factor for sensorineural hearing loss (SNHL) induced by aging, noise, ototoxic drugs, and gene. Reactive oxygen species (ROS) are mainly derived from mitochondria, and oxidative stress induced by ROS contributes to cochlear damage as well as mitochondrial DNA mutations, which may enhance the sensitivity and severity of hearing loss and disrupt ion homeostasis (e.g., Ca2+ homeostasis). The formation and accumulation of ROS further undermine mitochondrial components and ultimately lead to apoptosis and necrosis. SIRT3–5, located in mitochondria, belong to the family of sirtuins, which are highly conserved deacetylases dependent on nicotinamide adenine dinucleotide (NAD+). These deacetylases regulate diverse cellular biochemical activities. Recent studies have revealed that mitochondrial sirtuins, especially SIRT3, modulate ROS levels in hearing loss pathologies. Although the precise functions of SIRT4 and SIRT5 in the cochlea remain unclear, the molecular mechanisms in other tissues indicate a potential protective effect against hearing loss. In this review, we summarize the current knowledge regarding the role of mitochondrial dysfunction in hearing loss, discuss possible functional links between mitochondrial sirtuins and SNHL, and propose a perspective that SIRT3–5 have a positive effect on SNHL.
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15
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Holmgren M, Sheets L. Using the Zebrafish Lateral Line to Understand the Roles of Mitochondria in Sensorineural Hearing Loss. Front Cell Dev Biol 2021; 8:628712. [PMID: 33614633 PMCID: PMC7892962 DOI: 10.3389/fcell.2020.628712] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 12/23/2020] [Indexed: 01/05/2023] Open
Abstract
Hair cells are the mechanosensory receptors of the inner ear and can be damaged by noise, aging, and ototoxic drugs. This damage often results in permanent sensorineural hearing loss. Hair cells have high energy demands and rely on mitochondria to produce ATP as well as contribute to intracellular calcium homeostasis. In addition to generating ATP, mitochondria produce reactive oxygen species, which can lead to oxidative stress, and regulate cell death pathways. Zebrafish lateral-line hair cells are structurally and functionally analogous to cochlear hair cells but are optically and pharmacologically accessible within an intact specimen, making the zebrafish a good model in which to study hair-cell mitochondrial activity. Moreover, the ease of genetic manipulation of zebrafish embryos allows for the study of mutations implicated in human deafness, as well as the generation of transgenic models to visualize mitochondrial calcium transients and mitochondrial activity in live organisms. Studies of the zebrafish lateral line have shown that variations in mitochondrial activity can predict hair-cell susceptibility to damage by aminoglycosides or noise exposure. In addition, antioxidants have been shown to protect against noise trauma and ototoxic drug–induced hair-cell death. In this review, we discuss the tools and findings of recent investigations into zebrafish hair-cell mitochondria and their involvement in cellular processes, both under homeostatic conditions and in response to noise or ototoxic drugs. The zebrafish lateral line is a valuable model in which to study the roles of mitochondria in hair-cell pathologies and to develop therapeutic strategies to prevent sensorineural hearing loss in humans.
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Affiliation(s)
- Melanie Holmgren
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States
| | - Lavinia Sheets
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States.,Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
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16
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Qian X, He Z, Wang Y, Chen B, Hetrick A, Dai C, Chi F, Li H, Ren D. Hair cell uptake of gentamicin in the developing mouse utricle. J Cell Physiol 2020; 236:5235-5252. [PMID: 33368220 DOI: 10.1002/jcp.30228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 11/27/2020] [Accepted: 12/08/2020] [Indexed: 12/27/2022]
Abstract
Intratympanic injection of gentamicin has proven to be an effective therapy for intractable vestibular dysfunction. However, most studies to date have focused on the cochlea, so little is known about the distribution and uptake of gentamicin by the counterpart of the auditory system, specifically vestibular hair cells (HCs). Here, with a combination of in vivo and in vitro approaches, we used a gentamicin-Texas Red (GTTR) conjugate to investigate the mechanisms of gentamicin vestibulotoxicity in the developing mammalian utricular HCs. In vivo, GTTR fluorescence was concentrated in the apical cytoplasm and the cellular membrane of neonatal utricular HCs, but scarce in the nucleus of HCs and supporting cells. Quantitative analysis showed the GTTR uptake by striolar HCs was significantly higher than that in the extrastriola. In addition, the GTTR fluorescence intensity in the striola was increased gradually from 1 to 8 days, peaking at 8-9 days postnatally. In vitro, utricle explants were incubated with GTTR and candidate uptake conduits, including mechanotransduction (MET) channels and endocytosis in the HC, were inhibited separately. GTTR uptake by HCs could be inhibited by quinine, a blocker of MET channels, under both normal and stressed conditions. Meanwhile, endocytic inhibition only reduced GTTR uptake in the CoCl2 hypoxia model. In sum, the maturation of MET channels mediated uptake of GTTR into vestibular HCs. Under stressed conditions, MET channels play a pronounced role, manifested by channel-dependent stress enhanced GTTR permeation, while endocytosis participates in GTTR entry in a more selective manner.
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Affiliation(s)
- Xiaoqing Qian
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, China
| | - Ziyu He
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, China
| | - Yanmei Wang
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, China
| | - Binjun Chen
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, China
| | - Alisa Hetrick
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, USA
| | - Chunfu Dai
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, China
| | - Fanglu Chi
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, China
| | - Hongzhe Li
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, USA.,Department of Otolaryngology-Head and Neck Surgery, Loma Linda University School of Medicine, Loma Linda, California, USA
| | - Dongdong Ren
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, China
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17
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Pecha PP, Almishaal AA, Mathur PD, Hillas E, Johnson T, Price MS, Haller T, Yang J, Rajasekaran NS, Firpo MA, Park AH. Role of Free Radical Formation in Murine Cytomegalovirus-Induced Hearing Loss. Otolaryngol Head Neck Surg 2020; 162:709-717. [PMID: 32041493 DOI: 10.1177/0194599820901485] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES The goal of the study was to determine whether reactive oxygen species (ROS) mediates cytomegalovirus (CMV)-induced labyrinthitis. STUDY DESIGN Murine model of CMV infection. SETTING University of Utah laboratory. SUBJECTS AND METHODS Nrf2 knockout mice were inoculated with murine CMV. Auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs) were then performed on these and uninfected controls. BALB/c mice were inoculated with murine CMV to determine whether a marker for ROS production, dihydroethidium (DHE), is expressed 7 days after inoculation. Finally, 2 antioxidants-D-methionine and ACE-Mg (vitamins A, C, and E with magnesium)-were administered 1 hour before and after infection in inoculated mice for 14 days. Temporal bones were harvested at postnatal day 10 for DHE detection. ABR and DPOAE testing was done at postnatal day 30. Scanning electron microscopy was also performed at postnatal day 30 to evaluate outer hair cell integrity. RESULTS Nrf2-infected mice had worse hearing than uninfected mice (P < .001). A statistically significant increase in DHE fluorescence was detected in BALB/c-infected mice as compared with uninfected mice 7 days after inoculation. D-methionine- and ACE-Mg-treated mice demonstrated an attenuation of the DHE fluorescence and a significant improvement in ABR and DPOAE thresholds when compared with untreated infected controls (P < .0001). Scanning electron microscopy demonstrated less outer hair cell loss in the treated versus untreated infected controls. CONCLUSION These results demonstrate for the first time that excessive ROS mediates CMV-induced hearing loss in a mouse model.
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Affiliation(s)
- Phayvanh P Pecha
- Division of Pediatric Otolaryngology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Ali A Almishaal
- College of Applied Medical Sciences, University of Hail, Hail, Saudi Arabia
| | - Pranav D Mathur
- Otonomy Inc, San Diego, California, USA.,Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, USA
| | - Elaine Hillas
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Taelor Johnson
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Melissa S Price
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Travis Haller
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Jun Yang
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, USA.,Department of Ophthalmology, University of Utah, Salt Lake City, UT, USA
| | - Namakkal S Rajasekaran
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Division of Cardiovascular Medicine, Department of Medicine, University of Utah, School of Medicine, Salt Lake City, UT, USA
| | - Matthew A Firpo
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Albert H Park
- College of Applied Medical Sciences, University of Hail, Hail, Saudi Arabia.,Division of Otolaryngology-Head and Neck Surgery, University of Utah, Salt Lake City, Utah, USA
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18
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Wong HTC, Zhang Q, Beirl AJ, Petralia RS, Wang YX, Kindt K. Synaptic mitochondria regulate hair-cell synapse size and function. eLife 2019; 8:e48914. [PMID: 31609202 PMCID: PMC6879205 DOI: 10.7554/elife.48914] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/13/2019] [Indexed: 11/21/2022] Open
Abstract
Sensory hair cells in the ear utilize specialized ribbon synapses. These synapses are defined by electron-dense presynaptic structures called ribbons, composed primarily of the structural protein Ribeye. Previous work has shown that voltage-gated influx of Ca2+ through CaV1.3 channels is critical for hair-cell synapse function and can impede ribbon formation. We show that in mature zebrafish hair cells, evoked presynaptic-Ca2+ influx through CaV1.3 channels initiates mitochondrial-Ca2+ (mito-Ca2+) uptake adjacent to ribbons. Block of mito-Ca2+ uptake in mature cells depresses presynaptic-Ca2+ influx and impacts synapse integrity. In developing zebrafish hair cells, mito-Ca2+ uptake coincides with spontaneous rises in presynaptic-Ca2+ influx. Spontaneous mito-Ca2+ loading lowers cellular NAD+/NADH redox and downregulates ribbon size. Direct application of NAD+ or NADH increases or decreases ribbon size respectively, possibly acting through the NAD(H)-binding domain on Ribeye. Our results present a mechanism where presynaptic- and mito-Ca2+ couple to confer proper presynaptic function and formation.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Animals, Genetically Modified
- Calcium/metabolism
- Calcium Channel Agonists/pharmacology
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Signaling
- Cell Size
- Embryo, Nonmammalian
- Evoked Potentials, Auditory/physiology
- Eye Proteins/chemistry
- Eye Proteins/genetics
- Eye Proteins/metabolism
- Gene Expression
- Hair Cells, Auditory/cytology
- Hair Cells, Auditory/drug effects
- Hair Cells, Auditory/metabolism
- Isradipine/pharmacology
- Mitochondria/drug effects
- Mitochondria/metabolism
- Mitochondria/ultrastructure
- NAD/metabolism
- Oxidation-Reduction
- Protein Binding
- Protein Interaction Domains and Motifs
- Ruthenium Compounds/pharmacology
- Synapses/drug effects
- Synapses/metabolism
- Synapses/ultrastructure
- Synaptic Transmission
- Zebrafish
- Zebrafish Proteins/agonists
- Zebrafish Proteins/antagonists & inhibitors
- Zebrafish Proteins/chemistry
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism
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Affiliation(s)
- Hiu-tung C Wong
- Section on Sensory Cell Development and FunctionNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
- National Institutes of Health-Johns Hopkins University Graduate Partnership ProgramNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Qiuxiang Zhang
- Section on Sensory Cell Development and FunctionNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Alisha J Beirl
- Section on Sensory Cell Development and FunctionNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Ronald S Petralia
- Advanced Imaging CoreNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Ya-Xian Wang
- Advanced Imaging CoreNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Katie Kindt
- Section on Sensory Cell Development and FunctionNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
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19
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O’Reilly M, Young L, Kirkwood NK, Richardson GP, Kros CJ, Moore AL. Gentamicin Affects the Bioenergetics of Isolated Mitochondria and Collapses the Mitochondrial Membrane Potential in Cochlear Sensory Hair Cells. Front Cell Neurosci 2019; 13:416. [PMID: 31572129 PMCID: PMC6753894 DOI: 10.3389/fncel.2019.00416] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 08/29/2019] [Indexed: 01/11/2023] Open
Abstract
Aminoglycoside antibiotics are widely prescribed to treat a variety of serious bacterial infections. They are extremely useful clinical tools, but have adverse side effects such as oto- and nephrotoxicity. Once inside a cell they are thought to cause mitochondrial dysfunction, subsequently leading to apoptotic cell death due to an increase in reactive oxygen species (ROS) production. Here we present evidence of a direct effect of gentamicin (the most commonly prescribed aminoglycoside) on the respiratory activities of isolated rat liver and kidney mitochondria. We show that gentamicin stimulates state 4 and inhibits state 3u respiratory rates, thereby reducing the respiratory control ratio (RCR) whilst simultaneously causing a collapse of the mitochondrial membrane potential (MtMP). We propose that gentamicin behaves as an uncoupler of the electron transport chain (ETC) - a hypothesis supported by our evidence that it reduces the production of mitochondrial ROS (MtROS). We also show that gentamicin collapses the MtMP in the sensory hair cells (HCs) of organotypic mouse cochlear cultures.
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Affiliation(s)
- Molly O’Reilly
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Luke Young
- Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Nerissa K. Kirkwood
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Guy P. Richardson
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Corné J. Kros
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Anthony L. Moore
- Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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20
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García-Herreros M, Simintiras CA, Lonergan P. Temporally differential protein expression of glycolytic and glycogenic enzymes during in vitro preimplantation bovine embryo development. Reprod Fertil Dev 2019; 30:1245-1252. [PMID: 29566785 DOI: 10.1071/rd17429] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 03/01/2018] [Indexed: 12/11/2022] Open
Abstract
Proteomic analyses are useful for understanding the metabolic pathways governing embryo development. This study investigated the presence of enzymes involved in glycolysis and glycogenesis in in vitro-produced bovine embryos at five developmental stages leading up to blastocyst formation. The enzymes examined were: (1) glycolytic: hexokinase-I (HK-I), phosphofructokinase-1 (PFK-1), pyruvate kinase mutase 1/2 (PKM-1/2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and (2) glycogenic: glycogen synthase kinase-3 isoforms α/ β (GSK-3α/β). Glucose transporter-1 (GLUT-1) was also analysed. The developmental stages examined were: (1) 2-4-cell, (2) 5-8-cell, (3) 16-cell, (4) morula and (5) expanded blastocyst. The enzymes HK-I, PFK-1, PKM-1/2, GAPDH and GLUT-1 were differentially expressed throughout all stages (P<0.05). GSK-3α and β were also differentially expressed from the 2-4-cell to the expanded blastocyst stage (P<0.05) and GLUT-1 was identified throughout. The general trend was that the abundance of PFK1, GAPDH and PKM-1/2 decreased whereas HK-I, phospho-GSK3α (P-GSK3α) and P-GSK3β levels increased as the embryo advanced. In contrast, GLUT-1 expression peaked at the 16-cell stage. These data combined suggest that in vitro bovine embryo metabolism switches from being glycolytic-centric to glycogenic-centric around the 16-cell stage, the developmental window also characterised by embryonic genome activation.
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Affiliation(s)
- Manuel García-Herreros
- National Institute for Agricultural and Veterinary Research (INIAV, I.P.), Quinta da Fonte Boa 2005-048, Santarém, Portugal
| | - Constantine A Simintiras
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Dublin D04 N2E5, Ireland
| | - Patrick Lonergan
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Dublin D04 N2E5, Ireland
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21
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Kitcher SR, Kirkwood NK, Camci ED, Wu P, Gibson RM, Redila VA, Simon JA, Rubel EW, Raible DW, Richardson GP, Kros CJ. ORC-13661 protects sensory hair cells from aminoglycoside and cisplatin ototoxicity. JCI Insight 2019; 4:126764. [PMID: 31391343 PMCID: PMC6693895 DOI: 10.1172/jci.insight.126764] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 07/09/2019] [Indexed: 12/14/2022] Open
Abstract
Aminoglycoside (AG) antibiotics are widely used to prevent life-threatening infections, and cisplatin is used in the treatment of various cancers, but both are ototoxic and result in loss of sensory hair cells from the inner ear. ORC-13661 is a new drug that was derived from PROTO-1, a compound first identified as protective in a large-scale screen utilizing hair cells in the lateral line organs of zebrafish larvae. Here, we demonstrate, in zebrafish larvae and in mouse cochlear cultures, that ORC-13661 provides robust protection of hair cells against both ototoxins, the AGs and cisplatin. ORC-13661 also prevents both hearing loss in a dose-dependent manner in rats treated with amikacin and the loading of neomycin-Texas Red into lateral line hair cells. In addition, patch-clamp recordings in mouse cochlear cultures reveal that ORC-13661 is a high-affinity permeant blocker of the mechanoelectrical transducer (MET) channel in outer hair cells, suggesting that it may reduce the toxicity of AGs by directly competing for entry at the level of the MET channel and of cisplatin by a MET-dependent mechanism. ORC-13661 is therefore a promising and versatile protectant that reversibly blocks the hair cell MET channel and operates across multiple species and toxins. Candidate drug ORC-13661 robustly protects against ototoxicity by aminoglycoside antibiotics and cisplatin by reversibly blocking mechanotransduction of sensory hair cells.
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Affiliation(s)
- Siân R Kitcher
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Nerissa K Kirkwood
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Esra D Camci
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, USA
| | - Patricia Wu
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, USA.,Department of Biological Structure, University of Washington, Seattle, Washington, USA
| | - Robin M Gibson
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, USA
| | - Van A Redila
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, USA
| | - Julian A Simon
- Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Edwin W Rubel
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, USA
| | - David W Raible
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington, USA.,Department of Biological Structure, University of Washington, Seattle, Washington, USA
| | - Guy P Richardson
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Corné J Kros
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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22
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Mammano F. Inner Ear Connexin Channels: Roles in Development and Maintenance of Cochlear Function. Cold Spring Harb Perspect Med 2019; 9:a033233. [PMID: 30181354 PMCID: PMC6601451 DOI: 10.1101/cshperspect.a033233] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Connexin 26 and connexin 30 are the prevailing isoforms in the epithelial and connective tissue gap junction systems of the developing and mature cochlea. The most frequently encountered variants of the genes that encode these connexins, which are transcriptionally coregulated, determine complete loss of protein function and are the predominant cause of prelingual hereditary deafness. Reducing connexin 26 expression by Cre/loxP recombination in the inner ear of adult mice results in a decreased endocochlear potential, increased hearing thresholds, and loss of >90% of outer hair cells, indicating that this connexin is essential for maintenance of cochlear function. In the developing cochlea, connexins are necessary for intercellular calcium signaling activity. Ribbon synapses and basolateral membrane currents fail to mature in inner hair cells of mice that are born with reduced connexin expression, even though hair cells do not express any connexin. In contrast, pannexin 1, an alternative mediator of intercellular signaling, is dispensable for hearing acquisition and auditory function.
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Affiliation(s)
- Fabio Mammano
- University of Padova, Department of Physics and Astronomy "G. Galilei," Padova 35129, Italy
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
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23
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O'Reilly M, Kirkwood NK, Kenyon EJ, Huckvale R, Cantillon DM, Waddell SJ, Ward SE, Richardson GP, Kros CJ, Derudas M. Design, Synthesis, and Biological Evaluation of a New Series of Carvedilol Derivatives That Protect Sensory Hair Cells from Aminoglycoside-Induced Damage by Blocking the Mechanoelectrical Transducer Channel. J Med Chem 2019; 62:5312-5329. [PMID: 31083995 DOI: 10.1021/acs.jmedchem.8b01325] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aminoglycosides (AGs) are broad-spectrum antibiotics used for the treatment of serious bacterial infections but have use-limiting side effects including irreversible hearing loss. Here, we assessed the otoprotective profile of carvedilol in mouse cochlear cultures and in vivo zebrafish assays and investigated its mechanism of protection which, we found, may be mediated by a block of the hair cell's mechanoelectrical transducer (MET) channel, the major entry route for the AGs. To understand the full otoprotective potential of carvedilol, a series of 18 analogues were prepared and evaluated for their effect against AG-induced damage as well as their affinity for the MET channel. One derivative was found to confer greater protection than carvedilol itself in cochlear cultures and also to bind more tightly to the MET channel. At higher concentrations, both carvedilol and this derivative were toxic in cochlear cultures but not in zebrafish, suggesting a good therapeutic window under in vivo conditions.
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Affiliation(s)
| | | | | | | | - Daire M Cantillon
- Wellcome Trust Centre for Global Health Research, Brighton and Sussex Medical School , University of Sussex , Falmer , Brighton BN1 9PX , U.K
| | - Simon J Waddell
- Wellcome Trust Centre for Global Health Research, Brighton and Sussex Medical School , University of Sussex , Falmer , Brighton BN1 9PX , U.K
| | - Simon E Ward
- Medicines Discovery Institute , Cardiff University , Park Place , Cardiff CF10 3AT , U.K
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24
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Fujimoto C, Yamasoba T. Mitochondria-Targeted Antioxidants for Treatment of Hearing Loss: A Systematic Review. Antioxidants (Basel) 2019; 8:E109. [PMID: 31022870 PMCID: PMC6523236 DOI: 10.3390/antiox8040109] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 01/22/2023] Open
Abstract
Mitochondrial dysfunction is associated with the etiologies of sensorineural hearing loss, such as age-related hearing loss, noise- and ototoxic drug-induced hearing loss, as well as hearing loss due to mitochondrial gene mutation. Mitochondria are the main sources of reactive oxygen species (ROS) and ROS-induced oxidative stress is involved in cochlear damage. Moreover, the release of ROS causes further damage to mitochondrial components. Antioxidants are thought to counteract the deleterious effects of ROS and thus, may be effective for the treatment of oxidative stress-related diseases. The administration of mitochondria-targeted antioxidants is one of the drug delivery systems targeted to mitochondria. Mitochondria-targeted antioxidants are expected to help in the prevention and/or treatment of diseases associated with mitochondrial dysfunction. Of the various mitochondria-targeted antioxidants, the protective effects of MitoQ and SkQR1 against ototoxicity have been previously evaluated in animal models and/or mouse auditory cell lines. MitoQ protects against both gentamicin- and cisplatin-induced ototoxicity. SkQR1 also provides auditory protective effects against gentamicin-induced ototoxicity. On the other hand, decreasing effect of MitoQ on gentamicin-induced cell apoptosis in auditory cell lines has been controversial. No clinical studies have been reported for otoprotection using mitochondrial-targeted antioxidants. High-quality clinical trials are required to reveal the therapeutic effect of mitochondria-targeted antioxidants in terms of otoprotection in patients.
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Affiliation(s)
- Chisato Fujimoto
- Department of Otolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
- Department of Otolaryngology, Tokyo Teishin Hospital, 2-14-23, Fujimi, Chiyoda-ku, Tokyo 102-8798, Japan.
| | - Tatsuya Yamasoba
- Department of Otolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
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25
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Pickett SB, Raible DW. Water Waves to Sound Waves: Using Zebrafish to Explore Hair Cell Biology. J Assoc Res Otolaryngol 2019; 20:1-19. [PMID: 30635804 DOI: 10.1007/s10162-018-00711-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 12/19/2018] [Indexed: 01/09/2023] Open
Abstract
Although perhaps best known for their use in developmental studies, over the last couple of decades, zebrafish have become increasingly popular model organisms for investigating auditory system function and disease. Like mammals, zebrafish possess inner ear mechanosensory hair cells required for hearing, as well as superficial hair cells of the lateral line sensory system, which mediate detection of directional water flow. Complementing mammalian studies, zebrafish have been used to gain significant insights into many facets of hair cell biology, including mechanotransduction and synaptic physiology as well as mechanisms of both hereditary and acquired hair cell dysfunction. Here, we provide an overview of this literature, highlighting some of the particular advantages of using zebrafish to investigate hearing and hearing loss.
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Affiliation(s)
- Sarah B Pickett
- Department of Biological Structure, University of Washington, Health Sciences Building H-501, 1959 NE Pacific Street, Box 357420, Seattle, WA, 98195-7420, USA
- Graduate Program in Neuroscience, University of Washington, 1959 NE Pacific Street, Box 357270, Seattle, WA, 98195-7270, USA
| | - David W Raible
- Department of Biological Structure, University of Washington, Health Sciences Building H-501, 1959 NE Pacific Street, Box 357420, Seattle, WA, 98195-7420, USA.
- Graduate Program in Neuroscience, University of Washington, 1959 NE Pacific Street, Box 357270, Seattle, WA, 98195-7270, USA.
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, 1701 NE Columbia Rd, Box 357923, Seattle, WA, 98195-7923, USA.
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26
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Pickett SB, Thomas ED, Sebe JY, Linbo T, Esterberg R, Hailey DW, Raible DW. Cumulative mitochondrial activity correlates with ototoxin susceptibility in zebrafish mechanosensory hair cells. eLife 2018; 7:38062. [PMID: 30596476 PMCID: PMC6345563 DOI: 10.7554/elife.38062] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 12/31/2018] [Indexed: 12/11/2022] Open
Abstract
Mitochondria play a prominent role in mechanosensory hair cell damage and death. Although hair cells are thought to be energetically demanding cells, how mitochondria respond to these demands and how this might relate to cell death is largely unexplored. Using genetically encoded indicators, we found that mitochondrial calcium flux and oxidation are regulated by mechanotransduction and demonstrate that hair cell activity has both acute and long-term consequences on mitochondrial function. We tested whether variation in mitochondrial activity reflected differences in the vulnerability of hair cells to the toxic drug neomycin. We observed that susceptibility did not correspond to the acute level of mitochondrial activity but rather to the cumulative history of that activity.
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Affiliation(s)
- Sarah B Pickett
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States
| | - Eric D Thomas
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States
| | - Joy Y Sebe
- Department of Biological Structure, University of Washington, Seattle, United States
| | - Tor Linbo
- Department of Biological Structure, University of Washington, Seattle, United States
| | - Robert Esterberg
- Department of Biological Structure, University of Washington, Seattle, United States.,Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, United States
| | - Dale W Hailey
- Department of Biological Structure, University of Washington, Seattle, United States.,Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, United States
| | - David W Raible
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States.,Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, United States
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27
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Desa DE, Nichols MG, Smith HJ. Aminoglycosides rapidly inhibit NAD(P)H metabolism increasing reactive oxygen species and cochlear cell demise. JOURNAL OF BIOMEDICAL OPTICS 2018; 24:1-14. [PMID: 30411553 PMCID: PMC6225535 DOI: 10.1117/1.jbo.24.5.051403] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 09/21/2018] [Indexed: 06/04/2023]
Abstract
Despite causing permanent hearing loss by damaging inner ear sensory cells, aminoglycosides (AGs) remain one of the most widely used classes of antibiotics in the world. Although the mechanisms of cochlear sensory cell damage are not fully known, reactive oxygen species (ROS) are clearly implicated. Mitochondrial-specific ROS formation was evaluated in acutely cultured murine cochlear explants exposed to gentamicin (GM), a representative ototoxic AG antibiotic. Superoxide (O2·-) and hydrogen peroxide (H2O2) were measured using MitoSOX Red and Dihydrorhodamine 123, respectively, in sensory and supporting cells. A 1-h GM exposure significantly increased O2·- formation in IHCs and increased H2O2 formation in all cell types. At the same time point, GM significantly increased manganese superoxide dismutase (MnSOD) levels while significantly decreasing copper/zinc superoxide dismutase (CuZnSOD) in cochlear sensory cells. This suggests (1) a rapid conversion of highly reactive O2·- to H2O2 during the acute stage of ototoxic antibiotic exposure and (2) that the endogenous antioxidant system is significantly altered by AGs. Fluorescence intensity-based measurements of reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] and mitochondrial membrane potential were measured to determine if increases in GM-induced ROS production were correlated with changes in mitochondrial metabolism. This project provides a basis for understanding the mechanisms of mitochondrial ROS production in cochlear cells exposed to ototoxic antibiotics. Understanding the nature of ototoxic antibiotic-induced changes in mitochondrial metabolism is critical for developing hearing loss treatment and prevention strategies.
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Affiliation(s)
- Danielle E. Desa
- University of Rochester, Department of Biomedical Engineering, Rochester, New York, United States
| | - Michael G. Nichols
- Creighton University, Department of Physics, Omaha, Nebraska, United States
- Creighton University, Department of Biomedical Sciences, Omaha, Nebraska, United States
| | - Heather Jensen Smith
- University of Nebraska Medical Center, The Eppley Institute for Cancer and Allied Diseases, Omaha, Nebraska, United States
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28
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Fetoni AR, Zorzi V, Paciello F, Ziraldo G, Peres C, Raspa M, Scavizzi F, Salvatore AM, Crispino G, Tognola G, Gentile G, Spampinato AG, Cuccaro D, Guarnaccia M, Morello G, Van Camp G, Fransen E, Brumat M, Girotto G, Paludetti G, Gasparini P, Cavallaro S, Mammano F. Cx26 partial loss causes accelerated presbycusis by redox imbalance and dysregulation of Nfr2 pathway. Redox Biol 2018; 19:301-317. [PMID: 30199819 PMCID: PMC6129666 DOI: 10.1016/j.redox.2018.08.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/26/2018] [Accepted: 08/05/2018] [Indexed: 11/29/2022] Open
Abstract
Mutations in GJB2, the gene that encodes connexin 26 (Cx26), are the most common cause of sensorineural hearing impairment. The truncating variant 35delG, which determines a complete loss of Cx26 protein function, is the prevalent GJB2 mutation in several populations. Here, we generated and analyzed Gjb2+/- mice as a model of heterozygous human carriers of 35delG. Compared to control mice, auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs) worsened over time more rapidly in Gjb2+/- mice, indicating they were affected by accelerated age-related hearing loss (ARHL), or presbycusis. We linked causally the auditory phenotype of Gjb2+/- mice to apoptosis and oxidative damage in the cochlear duct, reduced release of glutathione from connexin hemichannels, decreased nutrient delivery to the sensory epithelium via cochlear gap junctions and deregulated expression of genes that are under transcriptional control of the nuclear factor erythroid 2-related factor 2 (Nrf2), a pivotal regulator of tolerance to redox stress. Moreover, a statistically significant genome-wide association with two genes (PRKCE and TGFB1) related to the Nrf2 pathway (p-value < 4 × 10-2) was detected in a very large cohort of 4091 individuals, originating from Europe, Caucasus and Central Asia, with hearing phenotype (including 1076 presbycusis patients and 1290 healthy matched controls). We conclude that (i) elements of the Nrf2 pathway are essential for hearing maintenance and (ii) their dysfunction may play an important role in the etiopathogenesis of human presbycusis.
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Affiliation(s)
- Anna Rita Fetoni
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy; Institute of Otolaryngology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo F. Vito 1, 00168 Rome, Italy
| | - Veronica Zorzi
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy
| | - Fabiola Paciello
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy
| | - Gaia Ziraldo
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy
| | - Chiara Peres
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy
| | - Marcello Raspa
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy
| | | | | | - Giulia Crispino
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy
| | - Gabriella Tognola
- CNR Institute of Electronics, Computer and Telecommunication Engineering, 20133 Milano, Italy
| | - Giulia Gentile
- CNR Institute of Neurological Sciences, 95126 Catania, Italy
| | | | - Denis Cuccaro
- CNR Institute of Neurological Sciences, 95126 Catania, Italy
| | | | | | - Guy Van Camp
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Universiteitsplein 1, 2610 Antwerp, Belgium
| | - Erik Fransen
- Department of Biomedical Sciences, University of Antwerp, 2650 Antwerp, Belgium
| | - Marco Brumat
- Dept Med Surg & Hlth Sci, University of Trieste, Trieste, Italy; IRCCS Burlo Garofolo, Inst Maternal & Child Hlth, Trieste, Italy
| | - Giorgia Girotto
- Dept Med Surg & Hlth Sci, University of Trieste, Trieste, Italy; IRCCS Burlo Garofolo, Inst Maternal & Child Hlth, Trieste, Italy
| | - Gaetano Paludetti
- Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy; Institute of Otolaryngology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo F. Vito 1, 00168 Rome, Italy
| | - Paolo Gasparini
- Dept Med Surg & Hlth Sci, University of Trieste, Trieste, Italy; IRCCS Burlo Garofolo, Inst Maternal & Child Hlth, Trieste, Italy.
| | | | - Fabio Mammano
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; University of Padova, Department of Physics and Astronomy "G. Galilei", Padova, Italy.
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29
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Yu JJ, Lee DH, Gallagher SP, Kenney MC, Boisvert CJ. Mitochondrial Impairment in Antibiotic Induced Toxic Optic Neuropathies. Curr Eye Res 2018; 43:1199-1204. [DOI: 10.1080/02713683.2018.1504086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Jeffrey J. Yu
- Department of Ophthalmology, University of California, Irvine, CA, USA
| | - Daniel H. Lee
- Department of Ophthalmology, University of California, Irvine, CA, USA
| | - Shea P. Gallagher
- Department of Ophthalmology, University of California, Irvine, CA, USA
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30
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Qi M, Qiu Y, Zhou X, Tian K, Zhou K, Sun F, Yue B, Chen F, Zha D, Qiu J. Regional up-regulation of NOX2 contributes to the differential vulnerability of outer hair cells to neomycin. Biochem Biophys Res Commun 2018; 500:110-116. [PMID: 29571735 DOI: 10.1016/j.bbrc.2018.03.141] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 03/19/2018] [Indexed: 11/26/2022]
Abstract
In hearing loss induced by aminoglycoside antibiotics, the outer hair cells (OHCs) in the basal turn are always more susceptible than OHCs in the apical turn, while the underlying mechanisms remain unknown. In this study, we reported that NAPDH oxidase 2 (NOX2) played an important role in the OHCs damage preferentially in the basal turn. Normally, NOX2 was evenly expressed in OHCs among different turns, at a relatively low level. However, after neomycin treatment, NOX2 was dominantly induced in OHCs in the basal turn. In vivo and in vitro studies demonstrated that inhibition of NOX2 significantly alleviated neomycin-induced OHCs damages, as seen from both the cleaved caspase-3 and TUNEL staining. Moreover, gp91 ds-tat delivery and DHE staining results showed that NOX2-derived ROS was responsible for neomycin ototoxicity. Taken together, our study shows that regional up-expression of NOX2 and subsequent increase of ROS in OHCs of the basal turn is an important factor contributing to the vulnerability of OHCs there, which should shed light on the prevention of hearing loss induced by aminoglycoside antibiotics.
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Affiliation(s)
- Meihao Qi
- Department of Otolaryngology Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yang Qiu
- Department of Otolaryngology Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xueying Zhou
- Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Keyong Tian
- Department of Otolaryngology Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ke Zhou
- Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Fei Sun
- Department of Otolaryngology Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Bo Yue
- Department of Otolaryngology Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Fuquan Chen
- Department of Otolaryngology Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Dingjun Zha
- Department of Otolaryngology Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
| | - Jianhua Qiu
- Department of Otolaryngology Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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31
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Noise-Induced Loss of Hair Cells and Cochlear Synaptopathy Are Mediated by the Activation of AMPK. J Neurosci 2017; 36:7497-510. [PMID: 27413159 DOI: 10.1523/jneurosci.0782-16.2016] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/31/2016] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Noise-induced hearing loss (NIHL) is a major unresolved public health problem. Here, we investigate pathomechanisms of sensory hair cell death and suggest a novel target for protective intervention. Cellular survival depends upon maintenance of energy homeostasis, largely by AMP-activated protein kinase (AMPK). In response to a noise exposure in CBA/J mice, the levels of phosphorylated AMPKα increased in hair cells in a noise intensity-dependent manner. Inhibition of AMPK via siRNA or the pharmacological inhibitor compound C attenuated noise-induced loss of outer hair cells (OHCs) and synaptic ribbons, and preserved auditory function. Additionally, noise exposure increased the activity of the upstream AMPK kinase liver kinase B1 (LKB1) in cochlear tissues. The inhibition of LKB1 by siRNA attenuated the noise-increased phosphorylation of AMPKα in OHCs, reduced the loss of inner hair cell synaptic ribbons and OHCs, and protected against NIHL. These results indicate that noise exposure induces hair cell death and synaptopathy by activating AMPK via LKB1-mediated pathways. Targeting these pathways may provide a novel route to prevent NIHL. SIGNIFICANCE STATEMENT Our results demonstrate for the first time that the activation of AMP-activated protein kinase (AMPK) α in sensory hair cells is noise intensity dependent and contributes to noise-induced hearing loss by mediating the loss of inner hair cell synaptic ribbons and outer hair cells. Noise induces the phosphorylation of AMPKα1 by liver kinase B1 (LKB1), triggered by changes in intracellular ATP levels. The inhibition of AMPK activation by silencing AMPK or LKB1, or with the pharmacological inhibitor compound C, reduced outer hair cell and synaptic ribbon loss as well as noise-induced hearing loss. This study provides new insights into mechanisms of noise-induced hearing loss and suggests novel interventions for the prevention of the loss of sensory hair cells and cochlear synaptopathy.
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32
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Antibiotics induce mitonuclear protein imbalance but fail to inhibit respiration and nutrient activation in pancreatic β-cells. Exp Cell Res 2017; 357:170-180. [PMID: 28527697 DOI: 10.1016/j.yexcr.2017.05.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 05/12/2017] [Accepted: 05/14/2017] [Indexed: 01/31/2023]
Abstract
Chloramphenicol and several other antibiotics targeting bacterial ribosomes inhibit mitochondrial protein translation. Inhibition of mitochondrial protein synthesis leads to mitonuclear protein imbalance and reduced respiratory rates as confirmed here in HeLa and PC12 cells. Unexpectedly, respiration in INS-1E insulinoma cells and primary human islets was unaltered in the presence of chloramphenicol. Resting respiratory rates and glucose stimulated acceleration of respiration were also not lowered when a range of antibiotics including, thiamphenicol, streptomycin, gentamycin and doxycycline known to interfere with bacterial protein synthesis were tested. However, chloramphenicol efficiently reduced mitochondrial protein synthesis in INS-1E cells, lowering expression of the mtDNA encoded COX1 subunit of the respiratory chain but not the nuclear encoded ATP-synthase subunit ATP5A. Despite a marked reduction of the essential respiratory chain subunit COX1, normal respiratory rates were maintained in INS-1E cells. ATP-synthase dependent respiration was even elevated in chloramphenicol treated INS-1E cells. Consistent with these findings, glucose-dependent calcium signaling reflecting metabolism-secretion coupling in beta-cells, was augmented. We conclude that antibiotics targeting mitochondria are able to cause mitonuclear protein imbalance in insulin secreting cells. We hypothesize that in contrast to other cell types, compensatory mechanisms are sufficiently strong to maintain normal respiratory rates and surprisingly even result in augmented ATP-synthase dependent respiration and calcium signaling following glucose stimulation. The result suggests that in insulin secreting cells only lowering COX1 below a threshold level may result in a measurable impairment of respiration. When focusing on mitochondrial function, care should be taken when including antibiotics targeting translation for long-term cell culture as depending on the sensitivity of the cell type analyzed, respiration, mitonuclear protein imbalance or down-stream signaling may be altered.
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Félix L, Oliveira M, Videira R, Maciel E, Alves ND, Nunes FM, Alves A, Almeida JM, Domingues MRM, Peixoto FP. Carvedilol exacerbate gentamicin-induced kidney mitochondrial alterations in adult rat. ACTA ACUST UNITED AC 2017; 69:83-92. [DOI: 10.1016/j.etp.2016.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/05/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
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Kohanski MA, Tharakan A, London NR, Lane AP, Ramanathan M. Bactericidal antibiotics promote oxidative damage and programmed cell death in sinonasal epithelial cells. Int Forum Allergy Rhinol 2017; 7:359-364. [PMID: 28117948 DOI: 10.1002/alr.21914] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 12/05/2016] [Accepted: 12/14/2016] [Indexed: 11/06/2022]
Abstract
BACKGROUND Antibiotics are widely and heavily used in the treatment of chronic sinusitis. Bactericidal antibiotics can stimulate reactive oxygen species (ROS) formation, a proinflammatory response, and cell death in cultured human sinonasal epithelial cells (SNECs). Sulforaphane (SFN) is a potent stimulator of the antioxidant nuclear factor erythroid 2-related factor 2 (Nrf-2) system and a suppressor of inflammation. In this study we utilized SFN to further explore the relationship between levofloxacin treatment, ROS formation, and the cell death response. METHODS SNECs were collected from patients during endoscopic sinus surgery and grown in culture at the air-liquid interface. Differentiated SNECs were stimulated with levofloxacin with or without SFN pretreatment. ROS were quantified. Apoptosis markers of caspase-3 activity and DNA fragmentation were quantified. RESULTS Cultured SNECs treated with levofloxacin resulted in a significant increase in activity of the proapoptotic caspase-3 protease (5.9-fold, p = 0.01). The increase in activity was suppressed by pretreatment with SFN (1.9-fold). ROS levels increased with levofloxacin treatment (range, 1.2-fold to 1.8-fold), but were not significantly suppressed by pretreatment with SFN (range, 1.0-fold to 1.3-fold). CONCLUSION In this study, we demonstrate that treatment of cultured SNECs with levofloxacin leads to an increase in caspase-3 activity. SFN pretreatment suppresses the increased apoptotic response possibly through its antioxidant stimulating properties. Our results suggest that levofloxacin treatment stimulates a potent proapoptotic possibly through an ROS-dependent mechanism. Future studies will explore if this antibiotic-induced response is harmful to recovery of function in those with sinusitis.
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Affiliation(s)
- Michael A Kohanski
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Anuj Tharakan
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nyall R London
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Andrew P Lane
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Murugappan Ramanathan
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD
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Abe J, Yamada Y, Harashima H. Validation of a Strategy for Cancer Therapy: Delivering Aminoglycoside Drugs to Mitochondria in HeLa Cells. J Pharm Sci 2016; 105:734-740. [PMID: 26523487 DOI: 10.1002/jps.24686] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/17/2015] [Accepted: 09/21/2015] [Indexed: 12/12/2022]
Abstract
Mitochondria in human cancer cells have been implicated in cancer cell proliferation, invasion, metastasis, and even drug-resistance mechanisms, making them a potential target organelle for the treatment of human malignancies. Gentamicin (GM), an aminoglycoside drug (AG), is a small molecule that functions as an antibiotic and has ototoxic and nephrotoxic characteristics. Thus, the delivery of GM to mitochondria in cancer cells would be an innovative anticancer therapeutic strategy. In this study, we attempted mitochondrial delivery of GM in HeLa cells derived from a human cervical cancer. For the mitochondrial delivery, we used MITO-Porter, a liposomal nanocarrier for mitochondrial delivery via membrane fusion. We first encapsulated GM in the aqueous phase of the carrier to construct GM-MITO-Porter. Flow cytometry analysis and fluorescent microscopy observations permitted us to confirm that the GM-MITO-Porter was efficiently taken up by HeLa cells and accumulated in mitochondria, whereas naked GM was not taken up by the cells. Moreover, cell viability assays using HeLa cells showed that the GM-MITO-Porter induced strong cytotoxic effects related to mitochondrial disorder. This finding is the first report of the mitochondrial delivery of an AG to cancer cells for cancer therapeutic strategy.
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Affiliation(s)
- Jiro Abe
- Department of Pediatrics, Graduate School of Medicine, Hokkaido University, Kita-ku, Sapporo 060-8638, Japan; Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan
| | - Yuma Yamada
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan
| | - Hideyoshi Harashima
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan.
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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: 85] [Impact Index Per Article: 9.4] [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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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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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: 130] [Impact Index Per Article: 14.4] [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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Bezdjian A, Mujica-Mota MA, Devic S, Daniel SJ. The Effect of Radiotherapy on Gentamicin Ototoxicity. Otolaryngol Head Neck Surg 2015; 152:1094-101. [DOI: 10.1177/0194599815573197] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 01/27/2015] [Indexed: 11/15/2022]
Abstract
Objective Patients undergoing radiotherapy (RT) often present with serious bacterial infections requiring the use of antibiotic treatment. Gentamicin is a commonly used aminoglycoside antibiotic, whose ototoxicity remains a major problem in clinical use. The objective of this study was to determine whether radiation exposure can influence gentamicin-induced ototoxicity. Study Design Prospective animal study. Setting Animal care facilities of the Montreal Children’s Hospital Research Institute. Methods Sixteen guinea pigs received low-dose RT unilaterally for 4 weeks (total: 48 Gy). Animals then received low or high doses of gentamicin (40 mg/kg/d and 80 mg/kg/d) for 10 days. The ears were divided into 4 groups: gentamicin 40 mg, gentamicin 80 mg, gentamicin 40 mg + RT, and gentamicin 80 + RT. Auditory brainstem responses and distortion products otoacoustic emissions were assessed at baseline and before and after gentamicin treatment. Cochlear morphology using light and scanning electron microscopy were evaluated. Results High-dose gentamicin caused significant auditory brainstem response threshold shifts ( P = .020), with greater hearing loss in the irradiated ear (difference of 23.6 + 7.5 dB). All animals exposed to high-dose gentamicin had head tilts toward the radiated side. Cochlear morphology revealed the greatest hair cell damage in the gentamicin 80 + RT group followed by gentamicin 80. Conclusion Results suggest that radiation can exacerbate the ototoxicity of gentamicin at high doses.
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Affiliation(s)
- Aren Bezdjian
- McGill Auditory Sciences Laboratory, McGill University, Montreal, Quebec, Canada
- Department of Otolaryngology–Head and Neck Surgery, The Montreal Children’s Hospital, Montreal, Quebec, Canada
| | - Mario A. Mujica-Mota
- McGill Auditory Sciences Laboratory, McGill University, Montreal, Quebec, Canada
- Department of Otolaryngology–Head and Neck Surgery, The Montreal Children’s Hospital, Montreal, Quebec, Canada
| | - Slobodan Devic
- Medical Physics Unit, McGill University, Montréal, Quebec, Canada
- Department of Radiation Oncology, Jewish General Hospital, Montreal, Quebec, Canada
| | - Sam J. Daniel
- McGill Auditory Sciences Laboratory, McGill University, Montreal, Quebec, Canada
- Department of Otolaryngology–Head and Neck Surgery, The Montreal Children’s Hospital, Montreal, Quebec, Canada
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Wang J, Wang Y, Chen X, Zhang PZ, Shi ZT, Wen LT, Qiu JH, Chen FQ. Histone deacetylase inhibitor sodium butyrate attenuates gentamicin-induced hearing loss in vivo. Am J Otolaryngol 2015; 36:242-8. [PMID: 25554003 DOI: 10.1016/j.amjoto.2014.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 11/14/2014] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Although histone deacetylase (HDAC) inhibition has been shown to protect against gentamicin (GM)-induced hearing loss in vitro, its protective effect has not been proven in vivo. In the present study, the aim was to investigate the protective effect of sodium butyrate (NaB), a specific HDAC inhibitor, on GM-induced ototoxicity in vivo. METHODS Forty 8-week-old albino guinea pigs were divided into two experimental groups. Group 1 (n=10) underwent bilateral ear surgery to place sponges (0.3mm(3)) permeated with NaB (10μl, 100mg/ml) and physiological saline (10μl; control) in the right and left round window niches, respectively. The sponges were left in place for 15days to evaluate the effects of NaB at the applied concentration. Group 2 (n=30) underwent the same bilateral ear surgery described for Group 1, except three days after surgery, the animals received intramuscular GM injections (200mg/kg/day) for 5 consecutive days. Seven days after the final GM injection, the protective effects of NaB were examined. RESULTS After 15days of NaB treatment (10μl, 100mg/ml), an increase in histone acetylation was detected in Corti organ samples. Auditory brainstem response (ABR) threshold shifts and hair cell loss were also reduced in NaB-treated ears after GM administration. Furthermore, GM treatment increased HDAC1 expression in outer hair cells (OHCs) in vivo, and NaB blocked this action. CONCLUSION GM increases HDAC1 expression in OHCs, and NaB is able to block this action. Thus, it appears that the HDAC inhibitor, NaB, attenuates GM-induced hearing loss in guinea pigs.
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Affiliation(s)
- Jie Wang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 17 Changle Western Road, Xi'an, China; Department of Otolaryngology-Head and Neck Surgery, Xi'an Children's Hospital, Shanxi, Xi'an, China
| | - Ye Wang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 17 Changle Western Road, Xi'an, China
| | - Xin Chen
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 17 Changle Western Road, Xi'an, China
| | - Peng-zhi Zhang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 17 Changle Western Road, Xi'an, China
| | - Ze-tao Shi
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 17 Changle Western Road, Xi'an, China
| | - Li-ting Wen
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 17 Changle Western Road, Xi'an, China
| | - Jian-hua Qiu
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 17 Changle Western Road, Xi'an, China
| | - Fu-quan Chen
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 17 Changle Western Road, Xi'an, China.
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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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Abstract
Mechanisms that lead to the death of hair cells are reviewed. Exposure to noise, the use of ototoxic drugs that damage the cochlea and old age are accompanied by hair cell death. Outer hair cells are often more susceptible than inner hair cells, partly because of an intrinsically greater susceptibility; high frequency cells are also more vulnerable. A common factor in hair cell loss following age-related changes and exposure to ototoxic drugs or high noise levels is the generation of reactive oxygen species, which can trigger intrinsic apoptosis (the mitochondrial pathway). However, hair cell death is sometimes produced via an extracellular signal pathway triggering extrinsic apoptosis. Necrosis and necroptosis also play a role and, in various situations in which cochlear damage occurs, a balance exists between these possible routes of cell death, with no one mechanism being exclusively activated. Finally, the numerous studies on these mechanisms of hair cell death have led to the identification of many potential therapeutic agents, some of which have been used to attempt to treat people exposed to damaging events, although clinical trials are not yet conclusive. Continued work in this area is likely to lead to clinical treatments that could be used to prevent or ameliorate hearing loss.
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Affiliation(s)
- David N Furness
- School of Life Sciences, Keele University, Keele, Staffordshire, ST5 5BG, UK,
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Sun S, Sun M, Zhang Y, Cheng C, Waqas M, Yu H, He Y, Xu B, Wang L, Wang J, Yin S, Chai R, Li H. In vivo overexpression of X-linked inhibitor of apoptosis protein protects against neomycin-induced hair cell loss in the apical turn of the cochlea during the ototoxic-sensitive period. Front Cell Neurosci 2014; 8:248. [PMID: 25278835 PMCID: PMC4166379 DOI: 10.3389/fncel.2014.00248] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/05/2014] [Indexed: 01/30/2023] Open
Abstract
Aminoglycoside-induced cochlear ototoxicity causes hair cell (HC) loss and results in hearing impairment in patients. Previous studies have developed the concept of an ototoxicity-sensitive period during which the cochleae of young mice are more vulnerable to auditory trauma than adults. Here, we compared neomycin-induced ototoxicity at the following four developmental ages in mice: postnatal day (P)1–P7, P8–P14, P15–P21, and P60–P66. We found that when neomycin was administered between P8 and P14, the auditory brainstem response threshold increase was significantly higher at low frequencies and HC loss was significantly greater in the apical turn of the cochlea compared to neomycin administration during the other age ranges. Quantitative real-time PCR (qPCR) data revealed that the expression of apoptotic markers, including Casp3 and Casp9, was significantly higher when neomycin was injected from P8 to P14, while the expression of the X-linked inhibitor of apoptosis protein (XIAP) gene was significantly higher when neomycin was injected from P60 to P66. Because XIAP expression was low during the neomycin-sensitive period, we overexpressed XIAP in mice and found that it could protect against neomycin-induced hearing loss at low frequencies and HC loss in the apical turn of the cochlea. Altogether, our findings demonstrate a protective role for XIAP against neomycin-induced hearing loss and HC loss in the apical turn of the cochlea during the ototoxic-sensitive period, and suggest that apoptotic factors mediate the effect of neomycin during the ototoxic-sensitive period.
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Affiliation(s)
- Shan Sun
- Research Center, Affiliated Eye and ENT Hospital of Fudan University Shanghai, China
| | - Mingzhi Sun
- Department of Otorhinolaryngology, Affiliated Eye and ENT Hospital of Fudan University Shanghai, China
| | - Yanping Zhang
- Research Center, Affiliated Eye and ENT Hospital of Fudan University Shanghai, China
| | - Cheng Cheng
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University Nanjing, China
| | - Muhammad Waqas
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University Nanjing, China
| | - Huiqian Yu
- Department of Otorhinolaryngology, Affiliated Eye and ENT Hospital of Fudan University Shanghai, China
| | - Yingzi He
- Research Center, Affiliated Eye and ENT Hospital of Fudan University Shanghai, China
| | - Bo Xu
- Anesthesiology Department, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Lei Wang
- Institute of Stem Cell and Regeneration Medicine, Institutions of Biomedical Science, Fudan University Shanghai, China ; State Key Laboratory of Genetic Engineering, MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University Shanghai, China
| | - Jian Wang
- Department of Otolaryngology, The Sixth Hospital Affiliated to Shanghai Jiao Tong University Shanghai, China
| | - Shankai Yin
- Department of Otolaryngology, The Sixth Hospital Affiliated to Shanghai Jiao Tong University Shanghai, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University Nanjing, China
| | - Huawei Li
- Department of Otorhinolaryngology, Affiliated Eye and ENT Hospital of Fudan University Shanghai, China ; Institute of Stem Cell and Regeneration Medicine, Institutions of Biomedical Science, Fudan University Shanghai, China ; State Key Laboratory of Medical Neurobiology, Fudan University Shanghai, China
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Abstract
Mechanosensory hair cells are vulnerable to environmental insult, resulting in hearing and balance disorders. We demonstrate that directional compartmental flow of intracellular Ca(2+) underlies death in zebrafish lateral line hair cells after exposure to aminoglycoside antibiotics, a well characterized hair cell toxin. Ca(2+) is mobilized from the ER and transferred to mitochondria via IP3 channels with little cytoplasmic leakage. Pharmacological agents that shunt ER-derived Ca(2+) directly to cytoplasm mitigate toxicity, indicating that high cytoplasmic Ca(2+) levels alone are not cytotoxic. Inhibition of the mitochondrial transition pore sensitizes hair cells to the toxic effects of aminoglycosides, contrasting with current models of excitotoxicity. Hair cells display efficient ER-mitochondrial Ca(2+) flow, suggesting that tight coupling of these organelles drives mitochondrial activity under physiological conditions at the cost of increased susceptibility to toxins.
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Vucovich MM, Cotton RB, Shelton EL, Goettel JA, Ehinger NJ, Poole SD, Brown N, Wynn JL, Paria BC, Slaughter JC, Clark RH, Rojas MA, Reese J. Aminoglycoside-mediated relaxation of the ductus arteriosus in sepsis-associated PDA. Am J Physiol Heart Circ Physiol 2014; 307:H732-40. [PMID: 24993047 PMCID: PMC4187398 DOI: 10.1152/ajpheart.00838.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 06/27/2014] [Indexed: 11/22/2022]
Abstract
Sepsis is strongly associated with patency of the ductus arteriosus (PDA) in critically ill newborns. Inflammation and the aminoglycoside antibiotics used to treat neonatal sepsis cause smooth muscle relaxation, but their contribution to PDA is unknown. We examined whether: 1) lipopolysaccharide (LPS) or inflammatory cytokines cause relaxation of the ex vivo mouse DA; 2) the aminoglycosides gentamicin, tobramycin, or amikacin causes DA relaxation; and 3) newborn infants treated with aminoglycosides have an increased risk of symptomatic PDA (sPDA). Changes in fetal mouse DA tone were measured by pressure myography in response to LPS, TNF-α, IFN-γ, macrophage-inflammatory protein 2, IL-15, IL-13, CXC chemokine ligand 12, or three aminoglycosides. A clinical database of inborn patients of all gestations was analyzed for association between sPDA and aminoglycoside treatment. Contrary to expectation, neither LPS nor any of the inflammatory mediators caused DA relaxation. However, each of the aminoglycosides caused concentration-dependent vasodilation in term and preterm mouse DAs. Pretreatment with indomethacin and N-(G)-nitro-L-arginine methyl ester did not prevent gentamicin-induced DA relaxation. Gentamicin-exposed DAs developed less oxygen-induced constriction than unexposed DAs. Among 488,349 infants who met the study criteria, 40,472 (8.3%) had sPDA. Confounder-adjusted odds of sPDA were higher in gentamicin-exposed infants, <25 wk and >32 wk. Together, these findings suggest that factors other than inflammation contribute to PDA. Aminoglycoside-induced vasorelaxation and inhibition of oxygen-induced DA constriction support the paradox that antibiotic treatment of sepsis may contribute to DA relaxation. This association was also found in newborn infants, suggesting that antibiotic selection may be an important consideration in efforts to reduce sepsis-associated PDA.
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Affiliation(s)
- Megan M Vucovich
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Robert B Cotton
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Elaine L Shelton
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Jeremy A Goettel
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Noah J Ehinger
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Stanley D Poole
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Naoko Brown
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - James L Wynn
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Bibhash C Paria
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - James C Slaughter
- Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | | | - Mario A Rojas
- Department of Pediatrics, Wake Forest University School of Medicine, Winston Salem, North Carolina
| | - Jeff Reese
- Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee;
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Coffin AB, Rubel EW, Raible DW. Bax, Bcl2, and p53 differentially regulate neomycin- and gentamicin-induced hair cell death in the zebrafish lateral line. J Assoc Res Otolaryngol 2013; 14:645-59. [PMID: 23821348 DOI: 10.1007/s10162-013-0404-1] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 06/20/2013] [Indexed: 12/19/2022] Open
Abstract
Sensorineural hearing loss is a normal consequence of aging and results from a variety of extrinsic challenges such as excessive noise exposure and certain therapeutic drugs, including the aminoglycoside antibiotics. The proximal cause of hearing loss is often death of inner ear hair cells. The signaling pathways necessary for hair cell death are not fully understood and may be specific for each type of insult. In the lateral line, the closely related aminoglycoside antibiotics neomycin and gentamicin appear to kill hair cells by activating a partially overlapping suite of cell death pathways. The lateral line is a system of hair cell-containing sense organs found on the head and body of aquatic vertebrates. In the present study, we use a combination of pharmacologic and genetic manipulations to assess the contributions of p53, Bax, and Bcl2 in the death of zebrafish lateral line hair cells. Bax inhibition significantly protects hair cells from neomycin but not from gentamicin toxicity. Conversely, transgenic overexpression of Bcl2 attenuates hair cell death due to gentamicin but not neomycin, suggesting a complex interplay of pro-death and pro-survival proteins in drug-treated hair cells. p53 inhibition protects hair cells from damage due to either aminoglycoside, with more robust protection seen against gentamicin. Further experiments evaluating p53 suggest that inhibition of mitochondrial-specific p53 activity confers significant hair cell protection from either aminoglycoside. These results suggest a role for mitochondrial p53 activity in promoting hair cell death due to aminoglycosides, likely upstream of Bax and Bcl2.
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Affiliation(s)
- Allison B Coffin
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Box 357923, Seattle, WA, 98195, USA,
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Disruption of intracellular calcium regulation is integral to aminoglycoside-induced hair cell death. J Neurosci 2013; 33:7513-25. [PMID: 23616556 DOI: 10.1523/jneurosci.4559-12.2013] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Intracellular Ca(2+) is a key regulator of life or death decisions in cultured neurons and sensory cells. The role of Ca(2+) in these processes is less clear in vivo, as the location of these cells often impedes visualization of intracellular Ca(2+) dynamics. We generated transgenic zebrafish lines that express the genetically encoded Ca(2+) indicator GCaMP in mechanosensory hair cells of the lateral line. These lines allow us to monitor intracellular Ca(2+) dynamics in real time during aminoglycoside-induced hair cell death. After exposure of live larvae to aminoglycosides, dying hair cells undergo a transient increase in intracellular Ca(2+) that occurs shortly after mitochondrial membrane potential collapse. Inhibition of intracellular Ca(2+) elevation through either caged chelators or pharmacological inhibitors of Ca(2+) effectors mitigates toxic effects of aminoglycoside exposure. Conversely, artificial elevation of intracellular Ca(2+) by caged Ca(2+) release agents sensitizes hair cells to the toxic effects of aminoglycosides. These data suggest that alterations in intracellular Ca(2+) homeostasis play an essential role in aminoglycoside-induced hair cell death, and indicate several potential therapeutic targets to stem ototoxicity.
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The mitochondrion: a perpetrator of acquired hearing loss. Hear Res 2013; 303:12-9. [PMID: 23361190 DOI: 10.1016/j.heares.2013.01.006] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 12/22/2012] [Accepted: 01/06/2013] [Indexed: 02/01/2023]
Abstract
Age, drugs, and noise are major causes of acquired hearing loss. The involvement of reactive oxygen species (ROS) in hair cell death has long been discussed, but there is considerably less information available as to the mechanisms underlying ROS formation. Most cellular ROS arise in mitochondria and this review will evaluate evidence for mitochondrial pathology in general and dysfunction of the mitochondrial respiratory chain in particular in acquired hearing loss. We will discuss evidence that different pathways can lead to the generation of ROS and that oxidative stress might not necessarily be causal to all three pathologies. Finally, we will detail recent advances in exploiting knowledge of aminoglycoside-mitochondria interactions for the development of non-ototoxic antibacterials. This article is part of a Special Issue entitled "Annual Reviews 2013".
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