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Li L, Chen D, Lin X, Luo J, Tan J, Ding D, Li P. Antioxidative Stress-Induced Destruction to Cochlear Cells Caused by Blind Antioxidant Therapy. Otolaryngol Head Neck Surg 2024; 170:1421-1429. [PMID: 38314899 DOI: 10.1002/ohn.659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 11/21/2023] [Accepted: 01/06/2024] [Indexed: 02/07/2024]
Abstract
OBJECTIVE Verification that blind and excessive use of antioxidants leads to antioxidant stress which exacerbates cochlear cell damage. STUDY DESIGN Basic research. SETTING The Third Affiliated Hospital of Sun Yat-Sen University. METHODS We compared and quantified hair cell-like house ear institute-organ of corti 1 (HEI-OC1) cell density, cell viability, and apoptosis caused by different concentrations of N-acetylcysteine (NAC) via Hoechst staining, Cell Counting Kit 8, Hoechst with propidium iodide staining, and Annexin V with propidium iodide (PI) staining. Apoptosis induced by high concentrations of M40403 and coenzyme Q10 in cochlear explants was analyzed and compared by cochlear dissection and activated caspase 3 labeling. RESULTS With the increase of NAC concentration (0-1000 μmol/L), cell density decreased consequently and reached the lowest at 1000 μmol/L (****P ≤ .0001). Cell viability is also declining (**P < .01). The number of Annexin V-fluorescein isothiocyanate-labeled cells and PI-labeled cells increased with increasing NAC concentration after treatment of HEI-OC1 cells for 48 hours. The proportion of apoptotic cells also rose (*P < .05, **P < .01). Cochlear hair cells (HCs) treated with low concentrations of M40403 and coenzyme Q10 for 48 hours showed no damage. When the concentrations of M40403 and coenzyme Q10 were increased (concentrations>30 μmol/L), HC damage began, followed by a dose-dependent increase in HC loss (*P < .001, **P < .0001). Activated caspase-3 was clearly apparent in cochlear explants treated with 50 μmol/L M40403 and coenzyme Q10 compared with cochlear explants without added M40403 and coenzyme Q10. CONCLUSION These experimental results suggest that inappropriate application of antioxidants can cause severe damage to normal cochlear HCs.
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Affiliation(s)
- Liling Li
- Department of Otolaryngology-Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guang Zhou, Guangdong, China
| | - Dan Chen
- Department of Otolaryngology-Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guang Zhou, Guangdong, China
| | - Xuexin Lin
- Department of Otolaryngology-Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guang Zhou, Guangdong, China
| | - Jia Luo
- Department of Otolaryngology-Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guang Zhou, Guangdong, China
| | - Jingqian Tan
- Department of Otolaryngology-Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guang Zhou, Guangdong, China
| | - Dalian Ding
- Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, Amherst, New York, USA
| | - Peng Li
- Department of Otolaryngology-Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guang Zhou, Guangdong, China
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Kim MJ, Carmichael PB, Bose U, Honkura Y, Suzuki J, Ding D, Erfe SL, Simms SS, Avaiya KA, Milani MN, Rymer EJ, Fragnito DT, Strom N, Salvi R, Someya S. Sex differences in body composition, voluntary wheel running activity, balance performance, and auditory function in CBA/CaJ mice across the lifespan. Hear Res 2023; 428:108684. [PMID: 36599258 DOI: 10.1016/j.heares.2022.108684] [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: 05/21/2022] [Revised: 12/12/2022] [Accepted: 12/26/2022] [Indexed: 12/28/2022]
Abstract
Hearing loss is the third most prevalent chronic health condition affecting older adults and age-related hearing loss (ARHL) is the most common form of hearing impairment. Significant sex differences in hearing have been documented in humans and rodents. In general, the results of these studies show that men lose their hearing more rapidly than women. However, the cellular mechanism underlying sex differences in hearing or hearing loss remains largely unknown, and to our knowledge, there is no well-established animal model for studying sex differences in hearing. In the current study, we examined sex differences in body composition, voluntary wheel running activity, balance performance, auditory function, and cochlear histology in young, middle-age, and old CBA/CaJ mice, a model of age-related hearing loss. As expected, body weight of young females was lower than that of males. Similarly, lean mass and total water mass of young, middle-age, and old females were lower than those of males. Young females showed higher voluntary wheel running activity during the dark cycle, an indicator of mobility, physical activity, and balance status, compared to males. Young females also displayed higher auditory brainstem response (ABR) wave I amplitudes at 8 kHz, wave II, III, V amplitudes at 8 and 48 kHz, and wave IV/I and V/I amplitude ratios at 48 kHz compared to males. Collectively, our findings suggest that the CBA/CaJ mouse strain is a useful model to study the cellular mechanisms underlying sex differences in physical activity and hearing.
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Affiliation(s)
- Mi-Jung Kim
- Department of Physiology and Aging, University of Florida, Gainesville, FL, USA
| | - Peter B Carmichael
- Department of Physiology and Aging, University of Florida, Gainesville, FL, USA
| | - Upal Bose
- Department of Physiology and Aging, University of Florida, Gainesville, FL, USA
| | - Yohei Honkura
- Department of Otolaryngology-Head &Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Jun Suzuki
- Department of Otolaryngology-Head &Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Dalian Ding
- Center for Hearing and Deafness, State University of New York at Buffalo, NY, USA
| | - Samantha L Erfe
- Department of Physiology and Aging, University of Florida, Gainesville, FL, USA; Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL, USA
| | - Shion S Simms
- Department of Physiology and Aging, University of Florida, Gainesville, FL, USA
| | - Kishan A Avaiya
- Department of Physiology and Aging, University of Florida, Gainesville, FL, USA
| | - Marcus N Milani
- Department of Physiology and Aging, University of Florida, Gainesville, FL, USA
| | - Elizabeth J Rymer
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL, USA
| | - Daniella T Fragnito
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL, USA
| | - Nathan Strom
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL, USA
| | - Richard Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo, NY, USA
| | - Shinichi Someya
- Department of Physiology and Aging, University of Florida, Gainesville, FL, USA; Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL, USA.
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3
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Li H, Oh SH, Shin HC, Suh MW. Intratympanic Administration of Dieckol Prevents Ototoxic Hearing Loss. Mar Drugs 2022; 20:md20100622. [PMID: 36286446 PMCID: PMC9604621 DOI: 10.3390/md20100622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Systemic administration of dieckol reportedly ameliorates acute hearing loss. In this study, dieckol was delivered to the inner ear by the intratympanic route. The functional and anatomic effects and safety of dieckol were assessed using the rat ototoxicity model. MATERIALS AND METHODS Dieckol in a high-molecular-weight hyaluronic acid vehicle (dieckol+vehicle group) or vehicle without dieckol (vehicle-only group) were randomly delivered into 12 ears intratympanically. Ototoxic hearing loss was induced by intravenous administration of cisplatin, gentamicin, and furosemide. The hearing threshold and surviving outer hair cells (OHC) were enumerated. Biocompatibility was assessed by serial endoscopy of the tympanic membrane (TM), and the histology of the TM and the base of bulla (BB) mucosa was quantitatively assessed. RESULTS The hearing threshold was significantly better (difference of 20 dB SPL) in the dieckol+vehicle group than in the vehicle-only group. The number of surviving OHCs was significantly greater in the dieckol+vehicle group than in the vehicle-only group. There were no signs of inflammation or infection in the ear. The thickness of the TM and the BB mucosa did not differ between the two groups. CONCLUSION Intratympanic local delivery of dieckol may be a safe and effective method to prevent ototoxic hearing loss.
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Affiliation(s)
- Hui Li
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul 03080, Korea
| | - Seung Ha Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul 03080, Korea
| | - Hyeon-Cheol Shin
- Center for Molecular Intelligence, The State University of New York, Incheon 21985, Korea
| | - Myung-Whan Suh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul 03080, Korea
- Correspondence: ; Tel.: +82-2-2072-3649; Fax: +82-2-745-2387
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4
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Cellular targets of mefloquine. Toxicology 2021; 464:152995. [PMID: 34678321 DOI: 10.1016/j.tox.2021.152995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/24/2022]
Abstract
Mefloquine is a quinoline-based compound widely used as an antimalarial drug, particularly in chemoprophylaxis. Although decades of research have identified various aspects of mefloquine's anti-Plasmodium properties, toxic effects offset its robust use in humans. Mefloquine exerts harmful effects in several types of human cells by targeting many of the cellular lipids, proteins, and complexes, thereby blocking a number of downstream signaling cascades. In general, mefloquine modulates several cellular phenomena, such as alteration of membrane potential, induction of oxidative stress, imbalance of ion homeostasis, disruption of metabolism, failure of organelle function, etc., leading to cell cycle arrest and programmed cell death. This review aims to summarize the information on functional and mechanistic findings related to the cytotoxic effects of mefloquine.
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5
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Ding D, Prolla T, Someya S, Manohar S, Salvi R. Roles of Bak and Sirt3 in Paraquat-Induced Cochlear Hair Cell Damage. Neurotox Res 2021; 39:1227-1237. [PMID: 33900547 DOI: 10.1007/s12640-021-00366-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/22/2022]
Abstract
Paraquat, a superoxide generator, can damage the cochlea causing an ototoxic hearing loss. The purpose of the study was to determine if deletion of Bak, a pro-apoptotic gene, would reduce paraquat ototoxicity or if deletion of Sirt3, which delays age-related hearing loss under caloric restriction, would increase paraquat ototoxicity. We tested these two hypotheses by treating postnatal day 3 cochlear cultures from Bak±, Bak-/-, Sirt3±, Sirt3-/-, and WT mice with paraquat and compared the results to a standard rat model of paraquat ototoxicity. Paraquat damaged nerve fibers and dose-dependently destroyed rat outer hair cells (OHCs) and inner hair cells (IHCs). Rat hair cell loss began in the base of the cochlea with a 10 μM dose and as the dose increased from 50 to 500 μM, the hair cell loss increased near the base of the cochlea and spread toward the apex of the cochlea. Rat OHC losses were consistently greater than IHC losses. Unexpectedly, in all mouse genotypes, paraquat-induced hair cell lesions were maximal near the apex of the cochlea and minimal near the base. This unusual damage gradient is opposite to that seen in paraquat-treated rats and in mice and rats treated with other ototoxic drugs. However, paraquat always induced greater OHC loss than IHC loss in all mouse strains. Contrary to our hypothesis, Bak deficient mice were more vulnerable to paraquat ototoxicity than WT mice (Bak-/- > Bak± > WT), suggesting that Bak plays a protective role against hair cell stress. Also, contrary to expectation, Sirt3-deficient mice did not differ significantly from WT mice, possibly due to the fact that Sirt3 was not experimentally upregulated in Sirt3-expressing mice prior to paraquat treatment. Our results show for the first time a gradient of ototoxic damage in mice that is greater in the apex than the base of the cochlea.
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MESH Headings
- Animals
- Animals, Newborn
- Cells, Cultured
- Cochlea/drug effects
- Cochlea/metabolism
- Cochlea/pathology
- Dose-Response Relationship, Drug
- Female
- Hair Cells, Auditory, Inner/drug effects
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Outer/drug effects
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/pathology
- Herbicides/toxicity
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Organ Culture Techniques
- Paraquat/toxicity
- Rats
- Rats, Sprague-Dawley
- Sirtuin 3/deficiency
- Sirtuin 3/genetics
- bcl-2 Homologous Antagonist-Killer Protein/deficiency
- bcl-2 Homologous Antagonist-Killer Protein/genetics
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Affiliation(s)
- Dalian Ding
- Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Tomas Prolla
- Department of Genetics and Medical Genetics, University of Wisconsin, 702 W Johnson St 1101, Madison, WI, 53715, USA
| | - Shinichi Someya
- Department of Aging and Geriatrics, University of Florida, Gainsville, FL, 32611, USA
| | - Senthilvelan Manohar
- Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Richard Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA.
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6
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Jozefowicz-Korczynska M, Pajor A, Lucas Grzelczyk W. The Ototoxicity of Antimalarial Drugs-A State of the Art Review. Front Neurol 2021; 12:661740. [PMID: 33959089 PMCID: PMC8093564 DOI: 10.3389/fneur.2021.661740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/04/2021] [Indexed: 11/19/2022] Open
Abstract
This review summarizes current knowledge about the occurrence of hearing and balance disorders after antimalarial drugs treatment. It also examines the clinical applications of antimalarials, their mechanisms behind this ototoxicity and how it can be monitored. It includes studies with larger numbers of patients and those in which auditory function was assessed using audiological tests. Some antimalarials have been repurposed for other conditions like autoimmune disorders, rheumatic diseases, some viral diseases and cancers. While old antimalarial drugs, such as quinoline derivatives, are known to demonstrate ototoxicity, a number of new synthetic antimalarial agents particularly artemisinin derivatives, demonstrate unknown ototoxicity. Adverse audiovestibular effects vary depending on the medication itself, its dose and route of administration, as well as the drug combination, treated disease and individual predispositions of the patient. Dizziness was commonly reported, while vestibular symptoms, hearing loss and tinnitus were observed much less frequently, and most of these symptoms were reversible. As early identification of ototoxic hearing loss is critical to introducing possible alternative treatments with less ototoxic medications, therefore monitoring systems of those drugs ototoxic side effects are much needed.
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Affiliation(s)
- Magdalena Jozefowicz-Korczynska
- Balance Disorders Unit, Otolaryngology Department, The Norbert Barlicki Memorial Teaching Hospital, Medical University of Lodz, Lodz, Poland
| | - Anna Pajor
- Department of Otolaryngology, Head and Neck Oncology, The Norbert Barlicki Memorial Teaching Hospital, Medical University of Lodz, Lodz, Poland
| | - Weronika Lucas Grzelczyk
- Balance Disorders Unit, Otolaryngology Department, The Norbert Barlicki Memorial Teaching Hospital, Medical University of Lodz, Lodz, Poland
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7
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Abstract
Abstract
Background
Lung adenocarcinoma is metastatic cancer with a high mortality rate. Circular RNAs (circRNAs) are a type of noncoding RNA and play a vital role in cancer progression. However, the expression and function of circRNAs in lung adenocarcinoma are still mostly unknown.
Methods
In this study, we screened the differential expression of circRNAs in human bronchial epithelial cells (HBE) and A549 human lung adenocarcinoma cell line (A549) by human circRNA microarray and RT-qPCR. The role of overexpressed circRNA_104889 in A549 cell proliferation, apoptosis, migration, and invasion was studied extensively. Intracellular localization of circRNA_104889 was visualized by FISH assay. MiRNA sponging, ERK1/2 signaling, and caspase-3 expression were analyzed in siRNA-mediated circRNA_104889 knockdowned A549 cells.
Results
CircRNA microarray showed overexpression of circRNA_104889 (> 13-fold) in A459 cells compared to HBE. This finding was further corroborated by the RT-qPCR result. CircRNA_104889 was mainly localized in the cytoplasm of A549 cells. The knockdown of circRNA_104889 in A549 cells by si-RNA mediated RNA interference did not affect cell proliferation and apoptosis but significantly inhibited cell migration and invasion in vitro. Furthermore, knockdown of circRNA_104889 led to an increase of miR4458 expression. Overexpression of miR4458 inhibited A549 cell migration. Both the knockdown of circRNA_104889 and overexpression of miR4458 inhibited the caspase-3 expression and ERK1/2 phosphorylation in A549 cells.
Conclusions
CircRNA_104889 promotes lung adenocarcinoma cell migration and invasion by sponging miR4458 and targeting ERK1/2 signaling and caspase-3 expression.
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Kim MJ, Han C, White K, Park HJ, Ding D, Boyd K, Rothenberger C, Bose U, Carmichael P, Linser PJ, Tanokura M, Salvi R, Someya S. Txn2 haplodeficiency does not affect cochlear antioxidant defenses or accelerate the progression of cochlear cell loss or hearing loss across the lifespan. Exp Gerontol 2020; 141:111078. [PMID: 32866605 DOI: 10.1016/j.exger.2020.111078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 07/16/2020] [Accepted: 08/25/2020] [Indexed: 11/16/2022]
Abstract
Thioredoxin 2 (TXN2) is a small redox protein found in nearly all organisms. As a mitochondrial member of the thioredoxin antioxidant defense system, TXN2 interacts with peroxiredoxin 3 (PRDX3) to remove hydrogen peroxide. Accordingly, TXN2 is thought to play an important role in maintaining the appropriate mitochondrial redox environment and protecting the mitochondrial components against oxidative stress. In the current study, we investigated the effects of Txn2 haplodeficiency on cochlear antioxidant defenses, auditory function, and cochlear cell loss across the lifespan in wild-type (WT) and Txn2 heterozygous knockout (Txn2+/-) mice backcrossed onto CBA/CaJ mice, a well-established model of age-related hearing loss. Txn2+/- mice displayed a 58% decrease in TXN2 protein levels in the mitochondria of the inner ears compared to WT mice. However, Txn2 haplodeficiency did not affect the thioredoxin or glutathione antioxidant defense in both the mitochondria and cytosol of the inner ears of young mice. There were no differences in the levels of mitochondrial biogenesis markers, mitochondrial DNA content, or oxidative DNA and protein damage markers in the inner ears between young WT and Txn2+/- mice. In a mouse inner ear cell line, knockdown of Txn2 did not affect cell viability under hydrogen peroxide treatment. Consistent with the tissue and cell line results, there were no differences in hair cell loss or spiral ganglion neuron density between WT and Txn2+/- mice at 3-5 or 23-25 months of age. Furthermore, Txn2 haplodeficiency did not affect auditory brainstem response threshold, wave I latency, or wave I amplitude at 3-5, 15-16, or 23-25 months of age. Therefore, Txn2 haplodeficiency does not affect cochlear antioxidant defenses, accelerate degeneration of cochlear cells, or affect auditory function in mice across the lifespan.
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Affiliation(s)
- Mi-Jung Kim
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA
| | - Chul Han
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA
| | - Karessa White
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA
| | - Hyo-Jin Park
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA
| | - Dalian Ding
- Center for Hearing and Deafness, State University of New York at Buffalo, NY, USA
| | - Kevin Boyd
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA
| | | | - Upal Bose
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA
| | - Peter Carmichael
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA
| | - Paul J Linser
- Whitney Laboratory, University of Florida, St Augustine, FL, USA
| | - Masaru Tanokura
- Department of Applied Biological Chemistry, University of Tokyo, Yayoi, Tokyo, Japan
| | - Richard Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo, NY, USA
| | - Shinichi Someya
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA.
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9
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Zhong Z, Fu X, Li H, Chen J, Wang M, Gao S, Zhang L, Cheng C, Zhang Y, Li P, Zhang S, Qian X, Shu Y, Chai R, Gao X. Citicoline Protects Auditory Hair Cells Against Neomycin-Induced Damage. Front Cell Dev Biol 2020; 8:712. [PMID: 32984303 PMCID: PMC7487320 DOI: 10.3389/fcell.2020.00712] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/13/2020] [Indexed: 01/07/2023] Open
Abstract
Aminoglycoside-induced hair cell (HC) loss is one of the most important causes of hearing loss. After entering the inner ear, aminoglycosides induce the production of high levels of reactive oxygen species (ROS) that subsequently activate apoptosis in HCs. Citicoline, a nucleoside derivative, plays a therapeutic role in central nervous system injury and in neurodegenerative disease models, including addictive disorders, stroke, head trauma, and cognitive impairment in the elderly, and has been widely used in the clinic as an FDA approved drug. However, its effect on auditory HCs remains unknown. Here, we used HC-like HEI-OC-1 cells and whole organ explant cultured mouse cochleae to explore the effect of citicoline on aminoglycoside-induced HC damage. Consistent with previous reports, both ROS levels and apoptosis were significantly increased in neomycin-induced cochlear HCs and HEI-OC-1 cells compared to undamaged controls. Interestingly, we found that co-treatment with citicoline significantly protected against neomycin-induced HC loss in both HEI-OC-1 cells and whole organ explant cultured cochleae. Furthermore, we demonstrated that citicoline could significantly reduce neomycin-induced mitochondrial dysfunction and inhibit neomycin-induced ROS accumulation and subsequent apoptosis. Thus, we conclude that citicoline can protect against neomycin-induced HC loss by inhibiting ROS aggregation and thus preventing apoptosis in HCs, and this suggests that citicoline might serve as a potential therapeutic drug in the clinic to protect HCs.
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Affiliation(s)
- Zhenhua Zhong
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China.,Department of Otolaryngology, Head and Neck Surgery, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Xiaolong Fu
- MOE Key Laboratory for Developmental Genes and Human Disease, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Institute of Life Sciences, Southeast University, Nanjing, China
| | - He Li
- Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jie Chen
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Maohua Wang
- Department of Otolaryngology, Head and Neck Surgery, Xiangya School of Medicine, Central South University, Changsha, China
| | - Song Gao
- Department of Otolaryngology, Affiliated People's Hospital of Jiangsu University, Zhenjiang, China
| | - Liyan Zhang
- MOE Key Laboratory for Developmental Genes and Human Disease, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Cheng Cheng
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Yuan Zhang
- MOE Key Laboratory for Developmental Genes and Human Disease, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Peipei Li
- School of Life Sciences, Shandong University, Jinan, China
| | - Shasha Zhang
- MOE Key Laboratory for Developmental Genes and Human Disease, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Xiaoyun Qian
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Yilai Shu
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology, Institute of Biomedical Sciences, NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Renjie Chai
- MOE Key Laboratory for Developmental Genes and Human Disease, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Institute of Life Sciences, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Xia Gao
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
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10
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Zhang C, Frye MD, Sun W, Sharma A, Manohar S, Salvi R, Hu BH. New insights on repeated acoustic injury: Augmentation of cochlear susceptibility and inflammatory reaction resultant of prior acoustic injury. Hear Res 2020; 393:107996. [PMID: 32534268 DOI: 10.1016/j.heares.2020.107996] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 04/29/2020] [Accepted: 05/12/2020] [Indexed: 12/20/2022]
Abstract
In industrial and military settings, individuals who suffer from one episode of acoustic trauma are likely to sustain another episode of acoustic stress, creating an opportunity for a potential interaction between the two stress conditions. We previously demonstrated that acoustic overstimulation perturbs the cochlear immune environment. However, how the cochlear immune system responds to repeated acoustic overstimulation is unknown. Here, we used a mouse model to investigate the cochlear immune response to repeated stress. We reveal that exposure to an intense noise at 120 dB SPL for 1 h activates the cochlear immune response in a time-dependent fashion with substantial expansion and activation of the macrophage population in the cochlea at 2-days post-exposure. At 20-days post-exposure, the number and pro-inflammatory phenotypes of cochlear macrophages have significantly subsided, but have yet to return to homeostatic levels. Monocytes with anti-inflammatory phenotypes are recruited into the cochlea. With the presence of this residual immune activation, a second exposure to the same noise provokes an exaggerated inflammatory response as evidenced by exacerbated maturation of macrophages. Furthermore, the second noise causes greater sensory cell pathogenesis. Unlike the first noise-induced damage that occurs mainly between 0 and 2 days post-exposure, the second noise-induced damage occurs more frequently between 2 and 20 days post-exposure, the period when secondary damage takes place. These observations suggest that repeated acoustic overstimulation exacerbates cochlear inflammation and secondary sensory cell pathogenesis. Together, our results suggest that the cochlear immune system plays an important role in modulating cochlear responses to repeated acoustic stress.
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Affiliation(s)
- Celia Zhang
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Mitchell D Frye
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Wei Sun
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Ashu Sharma
- Department of Oral Biology, University at Buffalo, School of Dental Medicine, University of Buffalo, The State University of New York, Buffalo, NY, USA, 14214.
| | - Senthilvelan Manohar
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Bo Hua Hu
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
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11
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Park HJ, Kim MJ, Han C, White K, Ding D, Boyd K, Salvi R, Someya S. Effects of Gsta4 deficiency on age-related cochlear pathology and hearing loss in mice. Exp Gerontol 2020; 133:110872. [PMID: 32044382 DOI: 10.1016/j.exger.2020.110872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 01/31/2020] [Accepted: 02/05/2020] [Indexed: 12/29/2022]
Abstract
The glutathione transferase (GST) detoxification system converts exogenous and endogenous toxins into a less toxic form by conjugating the toxic compound to reduced glutathione (GSH) by a variety of GST enzymes. Of the ~20 GST isoforms, GSTA4 exhibits high catalytic efficiency toward 4-hydroxynonenal (4-HNE), one of the most abundant end products of lipid peroxidation that contributes to neurodegenerative diseases and age-related disorders. Conjugation to GSH by GSTA4 is thought to be a major route of 4-HNE elimination. In the current study, we investigated the effects of Gsta4 deficiency on age-related cochlear pathology and hearing loss using young (3-5 months old) and old (24-25 months old) Gsta4+/+ and Gsta4-/- mice that were backcrossed onto the CBA/CaJ mouse strain, a well-established model of age-related hearing loss (AHL). At 3-5 months of age, loss of Gsta4 resulted in decreased total GSTA activity toward 4-HNE in the inner ears of young mice. However, there were no differences in the levels of 4-HNE in the inner ears between Gsta4+/+ and Gsta4-/- mice at 3-5 or 24-25 months of age. No histological abnormalities were observed in the cochlea and no hearing impairments were observed in young Gsta4-/- mice. At 24-25 months of age, both Gsta4+/+ and Gsta4-/- mice showed elevated ABR thresholds compared to 3-month-old mice, but there were no differences in ABR thresholds, cochlear spiral ganglion neuron densities, or stria vascularis thickness between Gsta4+/+ and Gsta4-/- mice. Together, these results suggest that under normal physiological conditions or during normal aging, GSTA4 is not essential for removal of 4-HNE in mouse inner ears.
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Affiliation(s)
- Hyo-Jin Park
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL 32611, USA
| | - Mi-Jung Kim
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL 32611, USA
| | - Chul Han
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL 32611, USA
| | - Karessa White
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL 32611, USA
| | - Dalian Ding
- Center for Hearing and Deafness, State University of New York at Buffalo, NY, USA
| | - Kevin Boyd
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL 32611, USA
| | - Richard Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo, NY, USA
| | - Shinichi Someya
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL 32611, USA.
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12
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Some Ototoxic Drugs Destroy Cochlear Support Cells Before Damaging Sensory Hair Cells. Neurotox Res 2020; 37:743-752. [PMID: 31997155 DOI: 10.1007/s12640-020-00170-8] [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] [Received: 10/30/2019] [Revised: 01/07/2020] [Accepted: 01/22/2020] [Indexed: 02/07/2023]
Abstract
A wide variety of ototoxic drugs are capable of damaging the sensory hair cells in the mammalian cochlea resulting in permanent hearing loss. However, the toxic properties of these drugs suggest that some could potentially damage cochlear support cells as well. To test the hypothesis, we treated postnatal day three rat cochlear cultures with toxic doses of gentamicin, cisplatin, mefloquine, and cadmium. Gentamicin primarily destroyed the hair cells and disrupted the intercellular connection with the surrounding support cells. Gentamicin-induced hair cell death was initiated through the caspase-9 intrinsic apoptotic pathway followed by activation of downstream executioner caspase-3. In contrast, cisplatin, mefloquine, and cadmium initially damaged the support cells and only later damaged the hair cells. Support cell death was initiated through the caspase-8 extrinsic apoptotic pathway followed later by downstream activation of caspase-3. Cisplatin, mefloquine, and cadmium significantly reduced the expression of actin and laminin, in the extracellular matrix, leading to significant disarray of the sensory epithelium.
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13
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Ding D, Zhang J, Liu F, Li P, Qi W, Xing Y, Shi H, Jiang H, Sun H, Yin S, Salvi R. Antioxidative stress-induced damage in cochlear explants. J Otol 2019; 15:36-40. [PMID: 32110239 PMCID: PMC7033592 DOI: 10.1016/j.joto.2019.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/26/2019] [Accepted: 11/27/2019] [Indexed: 12/31/2022] Open
Abstract
The imbalance of reactive oxygen species and antioxidants is considered to be an important factor in the cellular injury of the inner ear. At present, great attention has been placed on oxidative stress. However, little is known about fighting oxidative stress. In the current study, we evaluated antioxidant-induced cochlear damage by applying several different additional antioxidants. To determine whether excessive antioxidants can cause damage to cochlear cells, we treated cochlear explants with 50 μM M40403, a superoxide dismutase mimetic, 50 μM coenzyme Q-10, a vitamin-like antioxidant, or 50 μM d-methionine, an essential amino acid and the important antioxidant glutathione for 48 h. Control cochlear explants without the antioxidant treatment maintained their normal structures after incubation in the standard serum-free medium for 48 h, indicating the maintenance of the inherent oxidative and antioxidant balance in these cochlear explants. In contrast, M40403 and coenzyme Q-10-treated cochlear explants displayed significant hair cell damage together with slight damage to the auditory nerve fibers. Moreover, d-methiodine-treated explants exhibited severe damage to the surface structure of hair cells and the complete loss of the spiral ganglion neurons and their peripheral fibers. These results indicate that excessive antioxidants are detrimental to cochlear cells, suggesting that inappropriate dosages of antioxidant treatments can interrupt the balance of the inherent oxidative and antioxidant capacity in the cell.
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Affiliation(s)
- Dalian Ding
- Center for Hearing and Deafness, State University of New York at Buffalo, United States.,The Third People's Hospital of Chengdu, Chengdu, China.,Huashan Hospital, Fudan University, Shanghai, China
| | | | - Fang Liu
- Beijing Hospital and National Center of Gerontology, Department of Otolaryngology, Beijing, China
| | - Peng Li
- The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Weidong Qi
- Huashan Hospital, Fudan University, Shanghai, China
| | - Yazhi Xing
- Shanghai Six People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Haibo Shi
- Shanghai Six People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Haiyan Jiang
- Center for Hearing and Deafness, State University of New York at Buffalo, United States
| | - Hong Sun
- Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shankai Yin
- Shanghai Six People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Richard Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo, United States
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14
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Increased burden of mitochondrial DNA deletions and point mutations in early-onset age-related hearing loss in mitochondrial mutator mice. Exp Gerontol 2019; 125:110675. [PMID: 31344454 DOI: 10.1016/j.exger.2019.110675] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 07/14/2019] [Accepted: 07/20/2019] [Indexed: 11/20/2022]
Abstract
Mitochondrial DNA (mtDNA) mutations are thought to have a causal role in a variety of age-related neurodegenerative diseases, including age-related hearing loss (AHL). In the current study, we investigated the roles of mtDNA deletions and point mutations in AHL in mitochondrial mutator mice (Polgmut/mut) that were backcrossed onto CBA/CaJ mice, a well-established model of late-onset AHL. mtDNA deletions accumulated significantly with age in the inner ears of Polgmut/mut mice, while there were no differences in mtDNA deletion frequencies in the inner ears between 5 and 17 months old Polg+/+ mice or 5 months old Polg+/+ and Polgmut/mut mice. mtDNA deletions also accumulated significantly in the inner ears of CBA/CaJ mice during normal aging. In contrast, 5 months old Polgmut/mut mice displayed a 238-fold increase in mtDNA point mutation frequencies in the inner ears compared to age-matched Polg+/+ mice, but there were no differences in mtDNA point mutation frequencies in the inner ears between 5 and 17 months old Polgmut/mut mice. Seventeen-month-old Polgmut/mut mice also displayed early-onset severe hearing loss associated with a significant reduction in neural output of the cochlea, while age-matched Polg+/+ mice displayed little or no hearing impairment. Consistent with the physiological and mtDNA deletion test result, 17-month-old Polgmut/mut mice displayed a profound loss of spiral ganglion neurons in the cochlea. Thus, our data suggest that a higher burden of mtDNA point mutations from a young age and age-related accumulation of mtDNA deletions likely contribute to early-onset AHL in mitochondrial mutator mice.
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15
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Xuan Y, Ding D, Xuan W, Huang L, Tang J, Wei Y, Chen S, Hamblin MR. A traditional Chinese medicine compound (Jian Er) for presbycusis in a mouse model: Reduction of apoptosis and protection of cochlear sensorineural cells and hearing. INTERNATIONAL JOURNAL OF HERBAL MEDICINE 2018; 6:127-135. [PMID: 31890893 PMCID: PMC6936738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Age-related hearing loss (AHL) or presbycusis is steadily increasing due to the overall aging of the Chinese population. Traditional Chinese medicine (TCM) has long been used to prevent and treat deafness, but its effectiveness and mechanism of action are still uncertain. The present study tested a TCM preparation called "Jian Er" in a mouse model of prebycusis.
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Affiliation(s)
- Yi Xuan
- School of Engineering, Tufts University, Medford, MA, USA
| | - Dalian Ding
- Center for Hearing Deafness, the State University of New York at Buffalo, Buffalo, NY, USA
| | - Weijun Xuan
- Department of Otorhinolaryngology, Head and Neck Surgery, First Clinical Medical College and Hospital, Guangxi University of Chinese Medicine,Nanning, China
| | - Liyi Huang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
| | - Junbo Tang
- Department of Otorhinolaryngology, Head and Neck Surgery, First Clinical Medical College and Hospital, Guangxi University of Chinese Medicine, Nanning, China
| | - Yulong Wei
- Department of Pharmaceutical Manufacturing, Ruikang Clinical Medical College, Guangxi University of Chinese Medicine, Nanning, China
| | - Sizhong Chen
- Department of Otorhinolaryngology, Head and Neck Surgery, First Clinical Medical College and Hospital, Guangxi University of Chinese Medicine, Nanning, China
| | - Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
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16
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Abstract
A typical cochleogram was plotted to investigate hair cell densities as a percentage along the whole length of the basilar membrane (BM) of the rabbit, the length of the BM and the width of the organ of Corti. We generated surface preparations of cochlea from adult, healthy New Zealand White (NZW) rabbits. The numbers of inner hair cells (IHCs) and outer hair cells (OHCs) were counted from images acquired from a digital camera attached to an Olympus light microscope with a scale of 100 μm as a primary unit drawn continuously, and the numbers of IHCs and OHCs were converted to densities at 10% intervals along the length of the cochlea. Meanwhile, the length of the BM and the width of the organ of Corti were calculated. The average length of the cochlea was 14.504 ± 0.403 mm, while the total number of IHCs and the numbers of OHCs in the first, second, and third rows were 1556 ± 13, 1840 ± 47, 1842 ± 46, and 1840 ± 45, respectively, accounting for 21.98%, 26.00%, 26.02%, and 26.00% of the total number of cells, respectively. The densities of each row of OHCs reported in 10% intervals were greater than the densities of the IHCs corresponding to their anatomical locations within the cochlea. The densities of OHCs in each row were distributed uniformly along the BM, while the IHCs densities were not and showed a bimodal distribution with a maximum density at the apex and at 70–80% of the cochlear length from the apex but a lower density in the remaining cochlea. The width of the organ of Corti decreased successively from the apex to the base.
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17
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Zhang LW, Cang XH, Chen Y, Guan MX. In vitro culture of mammalian inner ear hair cells. J Zhejiang Univ Sci B 2018; 20:170-179. [PMID: 30187712 DOI: 10.1631/jzus.b1700613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Auditory function in vertebrates depends on the transduction of sound vibrations into electrical signals by inner ear hair cells. In general, hearing loss resulting from hair cell damage is irreversible because the human ear has been considered to be incapable of regenerating or repairing these sensory elements following severe injury. Therefore, regeneration and protection of inner ear hair cells have become an exciting, rapidly evolving field of research during the last decade. However, mammalian auditory hair cells are few in number, experimentally inaccessible, and barely proliferate postnatally in vitro. Various in vitro primary culture systems of inner ear hair cells have been established by different groups, although many challenges remain unresolved. Here, we briefly explain the structure of the inner ear, summarize the published methods of in vitro hair cell cultures, and propose a feasible protocol for culturing these cells, which gave satisfactory results in our study. A better understanding of in vitro hair cell cultures will substantially facilitate research involving auditory functions, drug development, and the isolation of critical molecules involved in hair cell biology.
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Affiliation(s)
- Lu-Wen Zhang
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xiao-Hui Cang
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Ye Chen
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou 310058, China
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18
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Dong Y, Zhang C, Frye M, Yang W, Ding D, Sharma A, Guo W, Hu BH. Differential fates of tissue macrophages in the cochlea during postnatal development. Hear Res 2018; 365:110-126. [PMID: 29804721 PMCID: PMC6026078 DOI: 10.1016/j.heares.2018.05.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/03/2018] [Accepted: 05/14/2018] [Indexed: 12/11/2022]
Abstract
The cochlea contains macrophages. These cells participate in inflammatory responses to cochlear pathogenesis. However, it is not clear how and when these cells populate the cochlea during postnatal development. The current study aims to determine the postnatal development of cochlear macrophages with the focus on macrophage development in the organ of Corti and the basilar membrane. Cochleae were collected from C57BL/6J mice at ages of postnatal day (P) 1 to P21, as well as from mature mice (1-4 months). Macrophages were identified based on their expression of F4/80 and Iba1, as well as their unique morphologies. Two sets of macrophages were identified in the regions of the organ of Corti and the basilar membrane. One set resides on the scala tympani side of the basilar membrane. These cells have a round shape at P1 and start to undergo site-specific differentiation at P4. Apical macrophages adopt a dendritic shape. Middle and basal macrophages take on an irregular shape with short projections. Basal macrophages further differentiate into an amoeboid shape. The other set of macrophages resides above the basilar membrane, either beneath the cells of the organ of Corti or along the spiral vessel of the basilar membrane. As the sensory epithelium matures, these cells undergo developmental death with the phenotypes of apoptosis. Macrophages are also identified in the spiral ligament, spiral limbus, and neural regions. Their numbers decrease during postnatal development. Together, these results suggest a dynamic rearrangement of the macrophage population during postnatal cochlear development.
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Affiliation(s)
- Youyi Dong
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Celia Zhang
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Mitchell Frye
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Weiping Yang
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA; Department of Otolaryngology and Head & Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, China.
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Ashu Sharma
- Department of Oral Biology, University at Buffalo, NY, 14214, USA.
| | - Weiwei Guo
- Department of Otolaryngology and Head & Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, China.
| | - Bo Hua Hu
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
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19
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Zhang J, Sun H, Salvi R, Ding D. Paraquat initially damages cochlear support cells leading to anoikis-like hair cell death. Hear Res 2018; 364:129-141. [PMID: 29563067 PMCID: PMC5984146 DOI: 10.1016/j.heares.2018.03.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/20/2018] [Accepted: 03/09/2018] [Indexed: 12/11/2022]
Abstract
Paraquat (PQ), one of the most widely used herbicides, is extremely dangerous because it generates the highly toxic superoxide radical. When paraquat was applied to cochlear organotypic cultures, it not only damaged the outer hair cells (OHCs) and inner hair cells (IHCs), but also caused dislocation of the hair cell rows. We hypothesized that the dislocation arose from damage to the support cells (SCs) that anchors hair cells within the epithelium. To test this hypothesis, rat postnatal cochlear cultures were treated with PQ. Shortly after PQ treatment, the rows of OHCs separated from one another and migrated radially away from IHCs suggesting loss of cell-cell adhesion that hold the hair cells in proper alignment. Hair cells dislocation was associated with extensive loss of SCs in the organ of Corti, loss of tympanic border cells (TBCs) beneath the basilar membrane, the early appearance of superoxide staining and caspase-8 labeling in SCs below the OHCs and disintegration of E-cadherin and β-catenin in the organ of Corti. Damage to the TBCs and SCs occurred prior to loss of OHC or IHC loss suggesting a form of detachment-induced apoptosis referred to as anoikis.
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Affiliation(s)
- Jianhui Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, China; Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA
| | - Hong Sun
- Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, China; Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA
| | - Richard Salvi
- Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, China; Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Audiology and Speech-Language Pathology, Asia University, Taichung, Taiwan, ROC
| | - Dalian Ding
- Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, China; Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA.
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20
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Seigel GM, Manohar S, Bai YY, Ding D, Salvi R. An immortalized microglial cell line (Mocha) derived from rat cochlea. Mol Cell Neurosci 2017; 85:202-210. [PMID: 29109020 DOI: 10.1016/j.mcn.2017.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 10/19/2017] [Accepted: 11/02/2017] [Indexed: 01/18/2023] Open
Abstract
Microglia are glial-immune cells that are essential for the function and survival of the central nervous system. Microglia not only protect neural tissues from immunological insults, but also play a critical role in neural development and repair. However, little is known about the biology of microglia in the cochlea, the auditory portion of the inner ear. In this study, we detected TMEM119+, CD11b+, CD45+ and Iba1+ populations of cells in the rat cochlea, particularly in Rosenthal's canal, inner sulcus and stria vascularis. Next, we isolated and enriched the population of CD11b+ cells from the cochlea and immortalized these cells with the 12S E1A gene of adenovirus in a replication-incompetent retroviral vector to derive a novel microglial cell line, designated Mocha (microglia of the cochlea). The resulting Mocha cells express a number of markers consistent with microglia and respond to lipopolysaccharide (LPS) stimulation by upregulation of genes (Cox2, ICAM-1, Il6r, Ccl2, Il13Ra and Il15Ra) as well as releasing cytokines (IL-1beta, IL-12, IL-13 and RANTES). As evidence of microglial function, Mocha cells phagocytose fluorescent beads at 37°C, but not at 4°C. The expression pattern of microglial markers in Mocha cells suggests that immortalization leads to a more primitive phenotype, a common phenomenon in immortalized cell lines. In summary, Mocha cells display key characteristics of microglia and are now available as a useful model system for the study of cochlear microglial behavior, both in vitro and in vivo.
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Affiliation(s)
- G M Seigel
- University at Buffalo, Center For Hearing & Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States.
| | - S Manohar
- University at Buffalo, Center For Hearing & Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States.
| | - Y Y Bai
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing 210009, China.
| | - D Ding
- University at Buffalo, Center For Hearing & Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States.
| | - R Salvi
- University at Buffalo, Center For Hearing & Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States; Department of Audiology and Speech-Language Pathology, Asia University, Taichung, Taiwan.
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21
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Gao K, Ding D, Sun H, Roth J, Salvi R. Kanamycin Damages Early Postnatal, but Not Adult Spiral Ganglion Neurons. Neurotox Res 2017; 32:603-613. [PMID: 28656549 PMCID: PMC5711550 DOI: 10.1007/s12640-017-9773-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/31/2017] [Accepted: 06/13/2017] [Indexed: 01/13/2023]
Abstract
Although aminoglycoside antibiotics such as kanamycin are widely used clinically to treat life-threatening bacterial infections, ototoxicity remains a significant dose-limiting side effect. The prevailing view is that the hair cells are the primary ototoxic target of aminoglycosides and that spiral ganglion neurons begin to degenerate weeks or months after the hair cells have died due to lack of neurotrophic support. To test the early developmental aspects of this issue, we compared kanamycin-induced hair cell and spiral ganglion pathology in rat postnatal day 3 cochlear organotypic cultures with adult whole cochlear explants. In both adult and postnatal day 3 cultures, hair cell damage began at the base of the cochleae and progressed toward the apex in a dose-dependent manner. In postnatal day 3 cultures, spiral ganglion neurons were rapidly destroyed by kanamycin prior to hair cell loss. In contrast, adult spiral ganglion neurons were resistant to kanamycin damage even at the highest concentration, consistent with in vivo models of delayed SGN degeneration. In postnatal day 3 cultures, kanamycin preferentially damaged type I spiral ganglion neurons, whereas type II neurons were resistant. Spiral ganglion degeneration of postnatal day 3 neurons was associated with upregulation of the superoxide radical and caspase-3-mediated cell death. These results show for the first time that kanamycin is toxic to postnatal day 3 spiral ganglion neurons, but not adult neurons.
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Affiliation(s)
- Kelei Gao
- Department of Otolaryngology Head and Neck Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410013, China
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Hong Sun
- Department of Otolaryngology Head and Neck Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410013, China
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Jerome Roth
- Department of Audiology and Speech-Language Pathology, Asia University, Taichung, Taiwan
| | - Richard Salvi
- Department of Otolaryngology Head and Neck Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410013, China.
- Department of Audiology and Speech-Language Pathology, Asia University, Taichung, Taiwan.
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22
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Effects of Long-Term Exercise on Age-Related Hearing Loss in Mice. J Neurosci 2017; 36:11308-11319. [PMID: 27807171 DOI: 10.1523/jneurosci.2493-16.2016] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/15/2016] [Indexed: 01/22/2023] Open
Abstract
Regular physical exercise reduces the risk for obesity, cardiovascular diseases, and disability and is associated with longer lifespan expectancy (Taylor et al., 2004; Pahor et al., 2014; Anton et al., 2015; Arem et al., 2015). In contrast, decreased physical function is associated with hearing loss among older adults (Li et al., 2013; Chen et al., 2015). Here, we investigated the effects of long-term voluntary wheel running (WR) on age-related hearing loss (AHL) in CBA/CaJ mice, a well established model of AHL (Zheng et al., 1999). WR activity peaked at 6 months of age (12,280 m/d) and gradually decreased over time. At 24 months of age, the average WR distance was 3987 m/d. Twenty-four-month-old runners had less cochlear hair cell and spiral ganglion neuron loss and better auditory brainstem response thresholds at the low and middle frequencies compared with age-matched, non-WR controls. Gene ontology (GO) enrichment analysis of inner ear tissues from 6-month-old controls and runners revealed that WR resulted in a marked enrichment for GO gene sets associated with immune response, inflammatory response, vascular function, and apoptosis. In agreement with these results, there was reduced stria vascularis (SV) atrophy and reduced loss of capillaries in the SV of old runners versus old controls. Given that SV holds numerous capillaries that are essential for transporting oxygen and nutrients into the cochlea, our findings suggest that long-term exercise delays the progression of AHL by reducing age-related loss of strial capillaries associated with inflammation. SIGNIFICANCE STATEMENT Nearly two-thirds of adults aged 70 years or older develop significant age-related hearing loss (AHL), a condition that can lead to social isolation and major communication difficulties. AHL is also associated with decreased physical function among older adults. In the current study, we show that regular exercise slowed AHL and cochlear degeneration significantly in a well established murine model. Our data suggest that regular exercise delays the progression of AHL by reducing age-related loss of strial capillaries associated with inflammation.
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Han C, Kim MJ, Ding D, Park HJ, White K, Walker L, Gu T, Tanokura M, Yamasoba T, Linser P, Salvi R, Someya S. GSR is not essential for the maintenance of antioxidant defenses in mouse cochlea: Possible role of the thioredoxin system as a functional backup for GSR. PLoS One 2017; 12:e0180817. [PMID: 28686716 PMCID: PMC5501606 DOI: 10.1371/journal.pone.0180817] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/21/2017] [Indexed: 11/18/2022] Open
Abstract
Glutathione reductase (GSR), a key member of the glutathione antioxidant defense system, converts oxidized glutathione (GSSG) to reduced glutathione (GSH) and maintains the intracellular glutathione redox state to protect the cells from oxidative damage. Previous reports have shown that Gsr deficiency results in defects in host defense against bacterial infection, while diquat induces renal injury in Gsr hypomorphic mice. In flies, overexpression of GSR extended lifespan under hyperoxia. In the current study, we investigated the roles of GSR in cochlear antioxidant defense using Gsr homozygous knockout mice that were backcrossed onto the CBA/CaJ mouse strain, a normal-hearing strain that does not carry a specific Cdh23 mutation that causes progressive hair cell degeneration and early onset of hearing loss. Gsr-/- mice displayed a significant decrease in GSR activity and GSH/GSSG ratios in the cytosol of the inner ears. However, Gsr deficiency did not affect ABR (auditory brainstem response) hearing thresholds, wave I amplitudes or wave I latencies in young mice. No histological abnormalities were observed in the cochlea of Gsr-/- mice. Furthermore, there were no differences in the activities of cytosolic glutathione-related enzymes, including glutathione peroxidase and glutamate-cysteine ligase, or the levels of oxidative damage markers in the inner ears between WT and Gsr-/- mice. In contrast, Gsr deficiency resulted in increased activities of cytosolic thioredoxin and thioredoxin reductase in the inner ears. Therefore, under normal physiological conditions, GSR is not essential for the maintenance of antioxidant defenses in mouse cochlea. Given that the thioredoxin system is known to reduce GSSG to GSH in multiple species, our findings suggest that the thioredoxin system can support GSSG reduction in the mouse peripheral auditory system.
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Affiliation(s)
- Chul Han
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States of America
| | - Mi-Jung Kim
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States of America
| | - Dalian Ding
- Center for Hearing and Deafness, State University of New York at Buffalo, NY, United States of America
| | - Hyo-Jin Park
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States of America
- Whitney Laboratory, University of Florida, St Augustine, FL, United States of America
| | - Karessa White
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States of America
| | - Logan Walker
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States of America
| | - Tongjun Gu
- Bioinformatics, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, United States of America
| | - Masaru Tanokura
- Department of Applied Biological Chemistry, University of Tokyo, Yayoi, Tokyo, Japan
| | - Tatsuya Yamasoba
- Department of Otolaryngology, University of Tokyo, Hongo, Tokyo, Japan
| | - Paul Linser
- Whitney Laboratory, University of Florida, St Augustine, FL, United States of America
| | - Richard Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo, NY, United States of America
| | - Shinichi Someya
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States of America
- * E-mail:
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G6pd Deficiency Does Not Affect the Cytosolic Glutathione or Thioredoxin Antioxidant Defense in Mouse Cochlea. J Neurosci 2017; 37:5770-5781. [PMID: 28473643 DOI: 10.1523/jneurosci.0519-17.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/25/2017] [Accepted: 04/26/2017] [Indexed: 11/21/2022] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) is the first and rate-limiting enzyme of the pentose phosphate pathway; it catalyzes the conversion of glucose-6-phosphate to 6-phosphogluconate and NADP+ to NADPH and is thought to be the principal source of NADPH for the cytosolic glutathione and thioredoxin antioxidant defense systems. We investigated the roles of G6PD in the cytosolic antioxidant defense in the cochlea of G6pd hypomorphic mice that were backcrossed onto normal-hearing CBA/CaJ mice. Young G6pd-deficient mice displayed a significant decrease in cytosolic G6PD protein levels and activities in the inner ears. However, G6pd deficiency did not affect the cytosolic NADPH redox state, or glutathione or thioredoxin antioxidant defense in the inner ears. No histological abnormalities or oxidative damage was observed in the cochlea of G6pd hemizygous males or homozygous females. Furthermore, G6pd deficiency did not affect auditory brainstem response hearing thresholds, wave I amplitudes or wave I latencies in young males or females. In contrast, G6pd deficiency resulted in increased activities and protein levels of cytosolic isocitrate dehydrogenase 1, an enzyme that catalyzes the conversion of isocitrate to α-ketoglutarate and NADP+ to NADPH, in the inner ear. In a mouse inner ear cell line, knockdown of Idh1, but not G6pd, decreased cell growth rates, cytosolic NADPH levels, and thioredoxin reductase activities. Therefore, under normal physiological conditions, G6pd deficiency does not affect the cytosolic glutathione or thioredoxin antioxidant defense in mouse cochlea. Under G6pd deficiency conditions, isocitrate dehydrogenase 1 likely functions as the principal source of NADPH for cytosolic antioxidant defense in the cochlea.SIGNIFICANCE STATEMENT Glucose-6-phosphate dehydrogenase (G6PD) is the first and rate-limiting enzyme of the pentose phosphate pathway; it catalyzes the conversion of glucose-6-phosphate to 6-phosphogluconate and NADP+ to NADPH and is thought to be the principal source of NADPH for the cytosolic glutathione and thioredoxin antioxidant defense systems. In the current study, we show that, under normal physiological conditions, G6pd deficiency does not affect the cytosolic glutathione or thioredoxin antioxidant defense in the mouse cochlea. However, under G6pd deficiency conditions, isocitrate dehydrogenase 1 likely functions as the principal source of NADPH for cytosolic antioxidant defense in the cochlea.
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Prakash Krishnan Muthaiah V, Ding D, Salvi R, Roth JA. Carbaryl-induced ototoxicity in rat postnatal cochlear organotypic cultures. ENVIRONMENTAL TOXICOLOGY 2017; 32:956-969. [PMID: 27296064 DOI: 10.1002/tox.22296] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/16/2016] [Accepted: 05/21/2016] [Indexed: 06/06/2023]
Abstract
Carbaryl, a widely used carbamate-based insecticide, is a potent anticholinesterase known to induce delayed neurotoxicity following chronic exposure. However, its potential toxic effects on the cochlea, the sensory organ for hearing that contains cholinergic efferent neurons and acetylcholine receptors on the hair cells (HC) and spiral ganglion neurons has heretofore not been evaluated. To assess ototoxic potential of carbaryl, cochlear organotypic cultures from postnatal day 3 rats were treated with doses of carbaryl ranging from 50 to 500 μM for 48 h up to 96 h. Carbaryl damaged both the sensory HC and spiral ganglion neurons in a dose- and duration-dependent manner. HC and neuronal damage was observed at carbaryl concentrations as low as 50 μM after 96-h treatment and 100 μM after 48-h treatment. Hair cell was greatest in the high frequency basal region of the cochlea and progressively decreased towards the apex consistent with the majority of ototoxic drugs. In contrast, damage to the spiral ganglion neurons was of similar magnitude in the basal and apical regions of the cochlea. Carbaryl damage was characterized by soma shrinkage, nuclear condensation and fragmentation, and blebbing, morphological features of programmed cell death. Carbaryl upregulated the expression of executioner caspase-3 in HC and spiral ganglion neurons indicating that cellular damage occurred primarily by caspase-mediated apoptosis. These results suggest that chronic exposure to carbaryl and other carbamate anticholinesterases may be ototoxic. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 956-969, 2017.
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Affiliation(s)
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, Buffalo, New York, 14214
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, New York, 14214
| | - Jerome A Roth
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, 14214
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Livezey J, Oliver T, Cantilena L. Prolonged Neuropsychiatric Symptoms in a Military Service Member Exposed to Mefloquine. DRUG SAFETY - CASE REPORTS 2016; 3:7. [PMID: 27747687 PMCID: PMC5005770 DOI: 10.1007/s40800-016-0030-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A 32-year-old male developed neuropsychiatric symptoms 2 weeks after starting mefloquine 250 mg/week for malaria prophylaxis. He continued to take the medication for the next 4 months. Initial symptoms included vivid dreams and anxiety, as well as balance problems. These symptoms persisted and progressed over the next 4 years to include vertigo, emotional lability, and poor short-term memory, which have greatly affected his personal and professional life. An extensive evaluation revealed objective evidence supporting a central vestibulopathy. These symptoms have been unresponsive to pharmacologic therapy and psychotherapy. A Naranjo assessment score of 6 was obtained for his initial symptoms, indicating a probable adverse drug reaction to mefloquine given the relationship between the clinical picture and drug exposure.
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Affiliation(s)
- Jeffrey Livezey
- Department of Clinical Pharmacology, Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD, 20910, USA.
| | - Thomas Oliver
- Division of Clinical Pharmacology and Medical Toxicology, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Louis Cantilena
- Division of Clinical Pharmacology and Medical Toxicology, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
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Zhu Y, Zhao KK, Tong Y, Zhou YL, Wang YX, Zhao PQ, Wang ZY. Exogenous NAD(+) decreases oxidative stress and protects H2O2-treated RPE cells against necrotic death through the up-regulation of autophagy. Sci Rep 2016; 6:26322. [PMID: 27240523 PMCID: PMC4886526 DOI: 10.1038/srep26322] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 05/03/2016] [Indexed: 01/08/2023] Open
Abstract
Increased oxidative stress, which can lead to the retinal pigment epithelium (RPE) cell death by inducing ATP depletion and DNA repair, is believed to be a prominent pathology in age-related macular degeneration (AMD). In the present study, we showed that and 0.1 mM nicotinamide adenine dinucleotide (NAD+) administration significantly blocked RPE cell death induced by 300 μM H2O2. Further investigation showed that H2O2 resulted in increased intracellular ROS level, activation of PARP-1 and subsequently necrotic death of RPE cells. Exogenous NAD+ administration significantly decreased intracellular and intranuclear ROS levels in H2O2-treated RPE cells. In addition, NAD+ administration to H2O2-treated RPE cells inhibited the activation of PARP-1 and protected the RPE cells against necrotic death. Moreover, exogenous NAD+ administration up-regulated autophagy in the H2O2-treated RPE cells. Inhibition of autophagy by LY294002 blocked the decrease of intracellular and intranuclear ROS level. Besides, inhibition of autophagy by LY294002 abolished the protection of exogenous NAD+ against H2O2-induced cell necrotic death. Taken together, our findings indicate that that exogenous NAD+ administration suppresses H2O2-induced oxidative stress and protects RPE cells against PARP-1 mediated necrotic death through the up-regulation of autophagy. The results suggest that exogenous NAD+ administration might be potential value for the treatment of AMD.
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Affiliation(s)
- Ying Zhu
- Department of Ophthalmology, Xinhua Hospital, Shanghai Jiaotong University Scool of Medicine, Shanghai, China
| | - Ke-Ke Zhao
- Department of Ophthalmology, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yao Tong
- Department of Ophthalmology, Xinhua Hospital, Shanghai Jiaotong University Scool of Medicine, Shanghai, China
| | - Ya-Li Zhou
- Department of Ophthalmology, Xinhua Hospital, Shanghai Jiaotong University Scool of Medicine, Shanghai, China
| | - Yi-Xiao Wang
- Department of Ophthalmology, Xinhua Hospital, Shanghai Jiaotong University Scool of Medicine, Shanghai, China
| | - Pei-Quan Zhao
- Department of Ophthalmology, Xinhua Hospital, Shanghai Jiaotong University Scool of Medicine, Shanghai, China
| | - Zhao-Yang Wang
- Department of Ophthalmology, Xinhua Hospital, Shanghai Jiaotong University Scool of Medicine, Shanghai, China
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Caito SW, Aschner M. NAD+ Supplementation Attenuates Methylmercury Dopaminergic and Mitochondrial Toxicity in Caenorhabditis Elegans. Toxicol Sci 2016; 151:139-49. [PMID: 26865665 DOI: 10.1093/toxsci/kfw030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Methylmercury (MeHg) is a neurotoxic contaminant of our fish supply that has been linked to dopaminergic (DAergic) dysfunction that characterizes Parkinson's disease. We have previously shown that MeHg causes both morphological and behavioral changes in the Caenorhabditis elegans DAergic neurons that are associated with oxidative stress. We were therefore interested in whether the redox sensitive cofactor nicotinamide adenine dinucleotide (NAD(+)) may be affected by MeHg and whether supplementation of NAD( + )may prevent MeHg-induced toxicities. Worms treated with MeHg showed depletion in cellular NAD( + )levels, which was prevented by NAD( + )supplementation prior to MeHg treatment. NAD( + )supplementation also prevented DAergic neurodegeneration and deficits in DAergic-dependent behavior upon MeHg exposure. In a mutant worm line that cannot synthesize NAD( + )from nicotinamide, MeHg lethality and DAergic behavioral deficits were more sensitive to MeHg than wildtype worms, demonstrating the importance of NAD( + )in MeHg toxicity. In wildtype worms, NAD( + )supplementation provided protection from MeHg-induced oxidative stress and mitochondrial dysfunction. These data show the importance of NAD( + )levels in the response to MeHg exposure. NAD( + )supplementation may be beneficial for MeHg-induced toxicities and preventing cellular damage involved in Parkinson's disease.
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Affiliation(s)
- Samuel W Caito
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
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Abstract
As most gene sequences and functional structures of internal organs in rats have been well studied, rat models are widely used in experimental medical studies. A large number of descriptions and atlas of the rat temporal bone have been published, but some detailed anatomy of its surface and inside structures remains to be studied. By focusing on some unique characteristics of the rat temporal bone, the current paper aims to provide more accurate and detailed information on rat temporal bone anatomy in an attempt to complete missing or unclear areas in the existed knowledge. We also hope this paper can lay a solid foundation for experimental rat temporal bone surgeries, and promote information exchange among colleagues, as well as providing useful guidance for novice researchers in the field of hearing research involving rats.
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Affiliation(s)
- Peng Li
- Department of Otolaryngology, Head and Neck Surgery, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.,Center for Hearing and Deafness, State University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Kelei Gao
- Center for Hearing and Deafness, State University of New York at Buffalo, Buffalo, NY 14214, USA.,Department of Otolaryngology, Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410013, China
| | - Dalian Ding
- Department of Otolaryngology, Head and Neck Surgery, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.,Center for Hearing and Deafness, State University of New York at Buffalo, Buffalo, NY 14214, USA.,Department of Otolaryngology, Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410013, China
| | - Richard Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo, Buffalo, NY 14214, USA.,Department of Otolaryngology, Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410013, China
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Quinn JC. Complex Membrane Channel Blockade: A Unifying Hypothesis for the Prodromal and Acute Neuropsychiatric Sequelae Resulting from Exposure to the Antimalarial Drug Mefloquine. J Parasitol Res 2015; 2015:368064. [PMID: 26576290 PMCID: PMC4630403 DOI: 10.1155/2015/368064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/28/2015] [Indexed: 12/18/2022] Open
Abstract
The alkaloid toxin quinine and its derivative compounds have been used for many centuries as effective medications for the prevention and treatment of malaria. More recently, synthetic derivatives, such as the quinoline derivative mefloquine (bis(trifluoromethyl)-(2-piperidyl)-4-quinolinemethanol), have been widely used to combat disease caused by chloroquine-resistant strains of the malaria parasite, Plasmodium falciparum. However, the parent compound quinine, as well as its more recent counterparts, suffers from an incidence of adverse neuropsychiatric side effects ranging from mild mood disturbances and anxiety to hallucinations, seizures, and psychosis. This review considers how the pharmacology, cellular neurobiology, and membrane channel kinetics of mefloquine could lead to the significant and sometimes life-threatening neurotoxicity associated with mefloquine exposure. A key role for mefloquine blockade of ATP-sensitive potassium channels and connexins in the substantia nigra is considered as a unifying hypothesis for the pathogenesis of severe neuropsychiatric events after mefloquine exposure in humans.
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Affiliation(s)
- Jane C. Quinn
- Plant and Animal Toxicology Group, School of Animal and Veterinary Sciences, Graham Centre for Agricultural Innovation, Charles Sturt University, Boorooma Street, Wagga Wagga, NSW 2650, Australia
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31
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Li P, Ding D, Salvi R, Roth JA. Cobalt-Induced Ototoxicity in Rat Postnatal Cochlear Organotypic Cultures. Neurotox Res 2015; 28:209-21. [PMID: 26153487 DOI: 10.1007/s12640-015-9538-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 06/28/2015] [Accepted: 06/30/2015] [Indexed: 01/01/2023]
Abstract
Cobalt (Co) is a required divalent metal used in the production of metal alloys, batteries, and pigments and is a component of vitamin B12. Excessive uptake of Co is neurotoxic causing temporary or permanent hearing loss; however, its ototoxic effects on the sensory hair cells, neurons, and support cells in the cochlea are poorly understood. Accordingly, we treated postnatal day 3 rat cochlear organotypic cultures with various doses and durations of CoCl2 and quantified the damage to the hair cells, peripheral auditory nerve fibers, and spiral ganglion neurons (SGN). Five-day treatment with 250 μM CoCl2 caused extensive damage to hair cells and neurons which increased with dose and treatment duration. CoCl2 caused greater damage to outer hair cells than inner hair cells; damage was greatest in the base of the cochlea and decreased towards the base. CoCl2 increased expression of superoxide radical in hair cells and SGNs and SGN loss was characterized by nuclear condensation and fragmentation, morphological features of apoptosis. CoCl2 treatment increased the expression of caspase-3 indicative of caspase-mediated programmed cell death. These results identify hair cells and spiral ganglion neurons as the main targets of Co ototoxicity in vitro and implicate the superoxide radical as a trigger of caspase-mediated ototoxicity.
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Affiliation(s)
- Peng Li
- Department of Otolaryngology Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guang Zhou, 510630, China
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Tang J, Qian Y, Li H, Kopecky BJ, Ding D, Ou HC, DeCook R, Chen X, Sun Z, Kobel M, Bao J. Canertinib induces ototoxicity in three preclinical models. Hear Res 2015; 328:59-66. [PMID: 26163095 DOI: 10.1016/j.heares.2015.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 06/23/2015] [Accepted: 07/03/2015] [Indexed: 12/16/2022]
Abstract
Neuregulin-1 (NRG1) ligand and its epidermal growth factor receptor (EGFR)/ERBB family regulate normal cellular proliferation and differentiation in many tissues including the cochlea. Aberrant NRG1 and ERBB signaling cause significant hearing impairment in mice. Dysregulation of the same signaling pathway in humans is involved in certain types of cancers such as breast cancer or non-small cell lung cancer (NSCLC). A new irreversible pan-ERBB inhibitor, canertinib, has been tested in clinical trials for the treatment of refractory NSCLC. Its possible ototoxicity was unknown. In this study, a significant dose-dependent canertinib ototoxicity was observed in a zebrafish model. Canertinib ototoxicity was further confirmed in two mouse models with different genetic backgrounds. The data strongly suggested an evolutionally preserved ERBB molecular mechanism underlying canertinib ototoxicity. Thus, these results imply that clinical monitoring of hearing loss should be considered for clinical testing of canertinib or other pan-ERBB inhibitors.
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Affiliation(s)
- Jian Tang
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Thoracic Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Yi Qian
- Department of Cardio-Thoracic Surgery, The Third Affiliated Hospital of Nantong University, Wuxi 214041, China
| | - Hui Li
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Benjamin J Kopecky
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Dalian Ding
- Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA
| | - Henry C Ou
- Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA; Department of Otolaryngology, University of Washington, Seattle, WA, USA
| | - Rhonda DeCook
- Department of Statistics and Actuarial Science, University of Iowa, Iowa City, IA 52242, USA
| | - Xiaojie Chen
- Gateway Biotechnology Inc., St. Louis, MO 63108, USA
| | - Zhenyu Sun
- Department of Cardio-Thoracic Surgery, The Third Affiliated Hospital of Nantong University, Wuxi 214041, China
| | - Megan Kobel
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Jianxin Bao
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH 44272, USA.
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Li P, Ding D, Gao K, Salvi R. Standardized surgical approaches to ear surgery in rats. J Otol 2015; 10:72-77. [PMID: 29937785 PMCID: PMC6002556 DOI: 10.1016/j.joto.2015.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 03/15/2015] [Accepted: 03/30/2015] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE To describe several approaches of ear surgeries for experimental studies in rats. METHODS Anesthetized rats were prepared for demonstration of various ear surgery approaches designed to optimize experimental outcomes in studies with specific goals and exposure requirements. The surgical approaches included the posterior tympanum, superior tympanum, inferior tympanum and occipital approaches. RESULTS The middle ear cavity and inner ear were successfully exposed from different angles via the mentioned surgical approaches. For example, electrode placement for recording of cochlear bioelectric responses was easily achieved through the posterior tympanum or inferior tympanum approach. Alternatively, drug delivery or gene transfection via round window membrane was most easily accomplished using the posterior tympanum approach. Cochlear perfusion of protective or ototoxic drugs was best performed using the inferior tympanum approach. Ossicular chain interruption to induce a prolonged conductive hearing loss was readily achieved using a superior tympanum approach. Lastly, surgical destruction of the endolymphatic sac to induce experimental endolymphatic hydrops was readily performed via an occipital surgical approach. CONCLUSION These standardized surgical approaches can be applied in scientific studies of the ear with different purposes covering electrophysiology, conductive hearing loss, intra-cochlear drug perfusion and experimental studies relevant to Meniere's disease.
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Affiliation(s)
- Peng Li
- Department of Otolaryngology Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510630, China
- Center for Hearing and Deafness, University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Dalian Ding
- Center for Hearing and Deafness, University of New York at Buffalo, Buffalo, NY 14214, USA
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410018, China
| | - Kelei Gao
- Center for Hearing and Deafness, University of New York at Buffalo, Buffalo, NY 14214, USA
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410018, China
| | - Richard Salvi
- Center for Hearing and Deafness, University of New York at Buffalo, Buffalo, NY 14214, USA
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410018, China
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34
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Zong L, Guan J, Ealy M, Zhang Q, Wang D, Wang H, Zhao Y, Shen Z, Campbell CA, Wang F, Yang J, Sun W, Lan L, Ding D, Xie L, Qi Y, Lou X, Huang X, Shi Q, Chang S, Xiong W, Yin Z, Yu N, Zhao H, Wang J, Wang J, Salvi RJ, Petit C, Smith RJH, Wang Q. Mutations in apoptosis-inducing factor cause X-linked recessive auditory neuropathy spectrum disorder. J Med Genet 2015; 52:523-31. [PMID: 25986071 PMCID: PMC4518735 DOI: 10.1136/jmedgenet-2014-102961] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/21/2015] [Indexed: 01/09/2023]
Abstract
Background Auditory neuropathy spectrum disorder (ANSD) is a form of hearing loss in which auditory signal transmission from the inner ear to the auditory nerve and brain stem is distorted, giving rise to speech perception difficulties beyond that expected for the observed degree of hearing loss. For many cases of ANSD, the underlying molecular pathology and the site of lesion remain unclear. The X-linked form of the condition, AUNX1, has been mapped to Xq23-q27.3, although the causative gene has yet to be identified. Methods We performed whole-exome sequencing on DNA samples from the AUNX1 family and another small phenotypically similar but unrelated ANSD family. Results We identified two missense mutations in AIFM1 in these families: c.1352G>A (p.R451Q) in the AUNX1 family and c.1030C>T (p.L344F) in the second ANSD family. Mutation screening in a large cohort of 3 additional unrelated families and 93 sporadic cases with ANSD identified 9 more missense mutations in AIFM1. Bioinformatics analysis and expression studies support this gene as being causative of ANSD. Conclusions Variants in AIFM1 gene are a common cause of familial and sporadic ANSD and provide insight into the expanded spectrum of AIFM1-associated diseases. The finding of cochlear nerve hypoplasia in some patients was AIFM1-related ANSD implies that MRI may be of value in localising the site of lesion and suggests that cochlea implantation in these patients may have limited success.
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Affiliation(s)
- Liang Zong
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Jing Guan
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Megan Ealy
- Molecular Otolaryngology and Renal Research Laboratories and the Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA Department of Otolaryngology-Head & Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Qiujing Zhang
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Dayong Wang
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Hongyang Wang
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Yali Zhao
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China Beijing Institute of Otorhinolaryngology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Zhirong Shen
- National Institute of Biological Sciences, Beijing, China
| | - Colleen A Campbell
- Molecular Otolaryngology and Renal Research Laboratories and the Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA
| | - Fengchao Wang
- National Institute of Biological Sciences, Beijing, China
| | - Ju Yang
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Wei Sun
- Department of Communicative Disorders & Sciences, Center for Hearing and Deafness, University at Buffalo, Buffalo, New York, USA
| | - Lan Lan
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Dalian Ding
- Department of Communicative Disorders & Sciences, Center for Hearing and Deafness, University at Buffalo, Buffalo, New York, USA
| | - Linyi Xie
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Yue Qi
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Xin Lou
- Department of Radiology, PLA General Hospital, Beijing, China
| | - Xusheng Huang
- Department of Neurology, PLA General Hospital, Beijing, China
| | - Qiang Shi
- Department of Neurology, PLA General Hospital, Beijing, China
| | - Suhua Chang
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Wenping Xiong
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Zifang Yin
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Ning Yu
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | - Hui Zhao
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
| | | | - Jing Wang
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Richard J Salvi
- Department of Communicative Disorders & Sciences, Center for Hearing and Deafness, University at Buffalo, Buffalo, New York, USA
| | - Christine Petit
- Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Collège de France, Paris, France
| | - Richard J H Smith
- Molecular Otolaryngology and Renal Research Laboratories and the Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA
| | - Qiuju Wang
- Department of Otolaryngology-Head and Neck Surgery, Institute of Otolaryngology, PLA General Hospital, Beijing, China
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35
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Autophagy in axonal degeneration in glaucomatous optic neuropathy. Prog Retin Eye Res 2015; 47:1-18. [PMID: 25816798 DOI: 10.1016/j.preteyeres.2015.03.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/14/2015] [Accepted: 03/19/2015] [Indexed: 01/07/2023]
Abstract
The role of autophagy in retinal ganglion cell (RGC) death is still controversial. Several studies focused on RGC body death, although the axonal degeneration pathway in the optic nerve has not been well documented in spite of evidence that the mechanisms of degeneration of neuronal cell bodies and their axons differ. Axonal degeneration of RGCs is a hallmark of glaucoma, and a pattern of localized retinal nerve fiber layer defects in glaucoma patients indicates that axonal degeneration may precede RGC body death in this condition. As models of preceding axonal degeneration, both the tumor necrosis factor (TNF) injection model and hypertensive glaucoma model may be useful in understanding the mechanism of axonal degeneration of RGCs, and the concept of axonal protection can be an attractive approach to the prevention of neurodegenerative optic nerve disease. Since mitochondria play crucial roles in glaucomatous optic neuropathy and can themselves serve as a part of the autophagosome, it seems that mitochondrial function may alter autophagy machinery. Like other neurodegenerative diseases, optic nerve degeneration may exhibit autophagic flux impairment resulting from elevated intraocular pressure, TNF, traumatic injury, ischemia, oxidative stress, and aging. As a model of aging, we used senescence-accelerated mice to provide new insights. In this review, we attempt to describe the relationship between autophagy and recently reported noteworthy factors including Nmnat, ROCK, and SIRT1 in the degeneration of RGCs and their axons and propose possible mechanisms of axonal protection via modulation of autophagy machinery.
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Chen Y, Li L, Ni W, Zhang Y, Sun S, Miao D, Chai R, Li H. Bmi1 regulates auditory hair cell survival by maintaining redox balance. Cell Death Dis 2015; 6:e1605. [PMID: 25611380 PMCID: PMC4669747 DOI: 10.1038/cddis.2014.549] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/13/2014] [Accepted: 11/17/2014] [Indexed: 01/06/2023]
Abstract
Reactive oxygen species (ROS) accumulation are involved in noise- and ototoxic drug-induced hair cell loss, which is the major cause of hearing loss. Bmi1 is a member of the Polycomb protein family and has been reported to regulate mitochondrial function and ROS level in thymocytes and neurons. In this study, we reported the expression of Bmi1 in mouse cochlea and investigated the role of Bmi1 in hair cell survival. Bmi1 expressed in hair cells and supporting cells in mouse cochlea. Bmi1−/− mice displayed severe hearing loss and patched outer hair cell loss from postnatal day 22. Ototoxic drug-induced hair cells loss dramatically increased in Bmi1−/− mice compared with that in wild-type controls both in vivo and in vitro, indicating Bmi1−/− hair cells were significantly more sensitive to ototoxic drug-induced damage. Cleaved caspase-3 and TUNEL staining demonstrated that apoptosis was involved in the increased hair cell loss of Bmi1−/− mice. Aminophenyl fluorescein and MitoSOX Red staining showed the level of free radicals and mitochondrial ROS increased in Bmi1−/− hair cells due to the aggravated disequilibrium of antioxidant–prooxidant balance. Furthermore, the antioxidant N-acetylcysteine rescued Bmi1−/− hair cells from neomycin injury both in vitro and in vivo, suggesting that ROS accumulation was mainly responsible for the increased aminoglycosides sensitivity in Bmi1−/− hair cells. Our findings demonstrate that Bmi1 has an important role in hair cell survival by controlling redox balance and ROS level, thus suggesting that Bmi1 may work as a new therapeutic target for the prevention of hair cell death.
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Affiliation(s)
- Y Chen
- 1] Department of Otorhinolaryngology, Hearing Research Institute, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China [2] Central Laboratory, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China
| | - L Li
- Department of Otorhinolaryngology, Hearing Research Institute, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China
| | - W Ni
- Department of Otorhinolaryngology, Hearing Research Institute, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China
| | - Y Zhang
- 1] Department of Otorhinolaryngology, Hearing Research Institute, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China [2] Central Laboratory, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China [3] Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - S Sun
- 1] Department of Otorhinolaryngology, Hearing Research Institute, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China [2] Central Laboratory, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China
| | - D Miao
- State Key Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Department of Human Anatomy, Nanjing Medical University, Nanjing 210096, China
| | - R Chai
- Co-innovation Center of Neuroregeneration, Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - H Li
- 1] Department of Otorhinolaryngology, Hearing Research Institute, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China [2] Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China [3] State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
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37
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Wang X, Li H, Ding S. The effects of NAD+ on apoptotic neuronal death and mitochondrial biogenesis and function after glutamate excitotoxicity. Int J Mol Sci 2014; 15:20449-68. [PMID: 25387075 PMCID: PMC4264177 DOI: 10.3390/ijms151120449] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/03/2014] [Indexed: 12/27/2022] Open
Abstract
NAD+ is an essential co-enzyme for cellular energy metabolism and is also involved as a substrate for many cellular enzymatic reactions. It has been shown that NAD+ has a beneficial effect on neuronal survival and brain injury in in vitro and in vivo ischemic models. However, the effect of NAD+ on mitochondrial biogenesis and function in ischemia has not been well investigated. In the present study, we used an in vitro glutamate excitotoxicity model of primary cultured cortical neurons to study the effect of NAD+ on apoptotic neuronal death and mitochondrial biogenesis and function. Our results show that supplementation of NAD+ could effectively reduce apoptotic neuronal death, and apoptotic inducing factor translocation after neurons were challenged with excitotoxic glutamate stimulation. Using different approaches including confocal imaging, mitochondrial DNA measurement and Western blot analysis of PGC-1 and NRF-1, we also found that NAD+ could significantly attenuate glutamate-induced mitochondrial fragmentation and the impairment of mitochondrial biogenesis. Furthermore, NAD+ treatment effectively inhibited mitochondrial membrane potential depolarization and NADH redistribution after excitotoxic glutamate stimulation. Taken together, our results demonstrated that NAD+ is capable of inhibiting apoptotic neuronal death after glutamate excitotoxicity via preserving mitochondrial biogenesis and integrity. Our findings provide insights into potential neuroprotective strategies in ischemic stroke.
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Affiliation(s)
- Xiaowan Wang
- Dalton Cardiovascular Research Center, Department of Bioengineering, University of Missouri, Columbia, MO 65211, USA.
| | - Hailong Li
- Dalton Cardiovascular Research Center, Department of Bioengineering, University of Missouri, Columbia, MO 65211, USA.
| | - Shinghua Ding
- Dalton Cardiovascular Research Center, Department of Bioengineering, University of Missouri, Columbia, MO 65211, USA.
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38
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Pattern of hair cell loss and delayed peripheral neuron degeneration in inner ear by a high-dose intratympanic gentamicin. J Otol 2014. [DOI: 10.1016/j.joto.2014.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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39
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Ramos-Martín V, González-Martínez C, Mackenzie I, Schmutzhard J, Pace C, Lalloo DG, Terlouw DJ. Neuroauditory toxicity of artemisinin combination therapies-have safety concerns been addressed? Am J Trop Med Hyg 2014; 91:62-73. [PMID: 24865683 PMCID: PMC4080570 DOI: 10.4269/ajtmh.13-0702] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Although artemisinin-based combination therapies (ACTs) are widely viewed as safe drugs with a wide therapeutic dose range, concerns about neuroauditory safety of artemisinins arose during their development. A decade ago, reviews of human data suggested a potential neuro-ototoxic effect, but the validity of these findings was questioned. With 5–10 years of programmatic use, emerging artemisinin-tolerant falciparum malaria in southeast Asia, and the first calls to consider an increased dose of artemisinins, we review neuroauditory safety data on ACTs to treat uncomplicated falciparum malaria. Fifteen studies reported a neurological or auditory assessment. The large heterogeneity of neuro-ototoxic end points and assessment methodologies and the descriptive nature of assessments hampered a formal meta-analysis and definitive conclusions, but they highlight the persistent lack of data from young children. This subgroup is potentially most vulnerable to any neuroauditory toxicity because of their development stage, increased malaria susceptibility, and repeated ACT exposure in settings lacking robust safety monitoring.
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Affiliation(s)
| | | | | | | | | | | | - Dianne J. Terlouw
- *Address correspondence to Dianne J. Terlouw, Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom. E-mail:
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40
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Nevin RL. Idiosyncratic quinoline central nervous system toxicity: Historical insights into the chronic neurological sequelae of mefloquine. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2014; 4:118-25. [PMID: 25057461 PMCID: PMC4095041 DOI: 10.1016/j.ijpddr.2014.03.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 03/17/2014] [Accepted: 03/19/2014] [Indexed: 12/04/2022]
Abstract
Regulators now warn adverse neurological effects from mefloquine may be irreversible. Many neurological effects resemble those of a common quinoline CNS toxidrome. The quinoline toxidrome is associated with a risk of CNS neuronal degeneration. CNS neuronal degeneration may underlie some neurological effects from mefloquine.
Mefloquine is a quinoline derivative antimalarial which demonstrates promise for the treatment of schistosomiasis. Traditionally employed in prophylaxis and treatment of chloroquine-resistant Plasmodium falciparum malaria, recent changes to the approved European and U.S. product labeling for mefloquine now warn of a risk of permanent and irreversible neurological sequelae including vertigo, loss of balance and symptoms of polyneuropathy. The newly described permanent nature of certain of these neurological effects challenges the conventional belief that they are due merely to the long half-life of mefloquine and its continued presence in the body, and raises new considerations for the rational use of the drug against parasitic disease. In this opinion, it is proposed that many of the reported lasting adverse neurological effects of mefloquine are consistent with the chronic sequelae of a well characterized but idiosyncratic central nervous system (CNS) toxicity syndrome (or toxidrome) common to certain historical antimalarial and antiparasitic quinolines and associated with a risk of permanent neuronal degeneration within specific CNS regions including the brainstem. Issues in the development and licensing of mefloquine are then considered in the context of historical awareness of the idiosyncratic CNS toxicity of related quinoline drugs. It is anticipated that the information presented in this opinion will aid in the future clinical recognition of the mefloquine toxidrome and its chronic sequelae, and in informing improved regulatory evaluation of mefloquine and related quinoline drugs as they are explored for expanded antiparasitic use and for other indications.
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Affiliation(s)
- Remington L Nevin
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, 624 N. Broadway, Room 782, Baltimore, MD 21205, United States
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41
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Wang L, Ding D, Salvi R, Roth JA. Nicotinamide adenine dinucleotide prevents neuroaxonal degeneration induced by manganese in cochlear organotypic cultures. Neurotoxicology 2013; 40:65-74. [PMID: 24308914 DOI: 10.1016/j.neuro.2013.11.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 11/19/2013] [Accepted: 11/25/2013] [Indexed: 01/17/2023]
Abstract
Manganese (Mn) is an essential trace mineral for normal growth and development. Persistent exposures to high atmospheric levels of Mn have deleterious effects on CNS and peripheral nerves including those associated with the auditory system. Nicotinamide adenine dinucleotide (NAD) is a coenzyme which functions in the electron transfer system within the mitochondria. One of the most notable protective functions of NAD is to delay axonal degenerations caused by various neurodegenerative injuries. We hypothesized that NAD might also protect auditory nerve fibers (ANF) and SGN from Mn injury. To test this hypothesis, cochlear organotypic cultures were treated with different doses of Mn (0.5-3.0 mM) alone or combined with 20 mM NAD. Results demonstrate that the percentage of hair cells, ANF and SGN decreased with increasing Mn concentration. The addition of 20 mM NAD did not significantly reduce hair cells loss in the presence of Mn, whereas the density of ANF and SGN increased significantly in the presence of NAD. NAD suppressed Mn-induced TUNEL staining and caspase activation suggesting it prevents apoptotic cell death. These results suggest that excess Mn has ototoxic and neurotoxic effects on the auditory system and that NAD may prevent Mn-induced axonal degeneration and avoid or delay hearing loss caused by excess Mn exposure.
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Affiliation(s)
- Lu Wang
- Department of Otolaryngology, Head and Neck Surgery, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, China; Center for Hearing and Deafness, University at Buffalo, Buffalo, NY 14214, United States
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY 14214, United States; Department of Otolaryngology, Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY 14214, United States
| | - Jerome A Roth
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, NY 14214, United States.
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