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Fuentes-Santamaría V, Benítez-Maicán Z, Alvarado JC, Fernández Del Campo IS, Gabaldón-Ull MC, Merchán MA, Juiz JM. Surface electrical stimulation of the auditory cortex preserves efferent medial olivocochlear neurons and reduces cochlear traits of age-related hearing loss. Hear Res 2024; 447:109008. [PMID: 38636186 DOI: 10.1016/j.heares.2024.109008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/19/2024] [Accepted: 04/11/2024] [Indexed: 04/20/2024]
Abstract
The auditory cortex is the source of descending connections providing contextual feedback for auditory signal processing at almost all levels of the lemniscal auditory pathway. Such feedback is essential for cognitive processing. It is likely that corticofugal pathways are degraded with aging, becoming important players in age-related hearing loss and, by extension, in cognitive decline. We are testing the hypothesis that surface, epidural stimulation of the auditory cortex during aging may regulate the activity of corticofugal pathways, resulting in modulation of central and peripheral traits of auditory aging. Increased auditory thresholds during ongoing age-related hearing loss in the rat are attenuated after two weeks of epidural stimulation with direct current applied to the surface of the auditory cortex for two weeks in alternate days (Fernández del Campo et al., 2024). Here we report that the same cortical electrical stimulation protocol induces structural and cytochemical changes in the aging cochlea and auditory brainstem, which may underlie recovery of age-degraded auditory sensitivity. Specifically, we found that in 18 month-old rats after two weeks of cortical electrical stimulation there is, relative to age-matched non-stimulated rats: a) a larger number of choline acetyltransferase immunoreactive neuronal cell body profiles in the ventral nucleus of the trapezoid body, originating the medial olivocochlear system.; b) a reduction of age-related dystrophic changes in the stria vascularis; c) diminished immunoreactivity for the pro-inflammatory cytokine TNFα in the stria vascularis and spiral ligament. d) diminished immunoreactivity for Iba1 and changes in the morphology of Iba1 immunoreactive cells in the lateral wall, suggesting reduced activation of macrophage/microglia; d) Increased immunoreactivity levels for calretinin in spiral ganglion neurons, suggesting excitability modulation by corticofugal stimulation. Altogether, these findings support that non-invasive neuromodulation of the auditory cortex during aging preserves the cochlear efferent system and ameliorates cochlear aging traits, including stria vascularis dystrophy, dysregulated inflammation and altered excitability in primary auditory neurons.
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Affiliation(s)
- V Fuentes-Santamaría
- School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008, Albacete, Spain
| | - Z Benítez-Maicán
- School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008, Albacete, Spain
| | - J C Alvarado
- School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008, Albacete, Spain
| | - I S Fernández Del Campo
- Lab. of Auditory Neuroplasticity, Institute for Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain
| | - M C Gabaldón-Ull
- School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008, Albacete, Spain
| | - M A Merchán
- Lab. of Auditory Neuroplasticity, Institute for Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain
| | - J M Juiz
- School of Medicine, Universidad de Castilla-La Mancha (UCLM), Campus in Albacete, 02008, Albacete, Spain; Hannover Medical School, Dept. of Otolaryngology and Cluster of Excellence "H4all" of the German Research Foundation, DFG, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
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Bovee S, Klump GM, Köppl C, Pyott SJ. The Stria Vascularis: Renewed Attention on a Key Player in Age-Related Hearing Loss. Int J Mol Sci 2024; 25:5391. [PMID: 38791427 DOI: 10.3390/ijms25105391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Revised: 05/08/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
Age-related hearing loss (HL), or presbycusis, is a complex and heterogeneous condition, affecting a significant portion of older adults and involving various interacting mechanisms. Metabolic presbycusis, a type of age-related HL, is characterized by the dysfunction of the stria vascularis, which is crucial for maintaining the endocochlear potential necessary for hearing. Although attention on metabolic presbycusis has waned in recent years, research continues to identify strial pathology as a key factor in age-related HL. This narrative review integrates past and recent research, bridging findings from animal models and human studies, to examine the contributions of the stria vascularis to age-related HL. It provides a brief overview of the structure and function of the stria vascularis and then examines mechanisms contributing to age-related strial dysfunction, including altered ion transport, changes in pigmentation, inflammatory responses, and vascular atrophy. Importantly, this review outlines the contribution of metabolic mechanisms to age-related HL, highlighting areas for future research. It emphasizes the complex interdependence of metabolic and sensorineural mechanisms in the pathology of age-related HL and highlights the importance of animal models in understanding the underlying mechanisms. The comprehensive and mechanistic investigation of all factors contributing to age-related HL, including cochlear metabolic dysfunction, remains crucial to identifying the underlying mechanisms and developing personalized, protective, and restorative treatments.
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Affiliation(s)
- Sonny Bovee
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| | - Georg M Klump
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Cluster of Excellence "Hearing4all", Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| | - Christine Köppl
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Cluster of Excellence "Hearing4all", Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| | - Sonja J Pyott
- Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
- The Research School of Behavioural and Cognitive Neurosciences, University of Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
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Lao H, Zhu Y, Yang M, Wang L, Tang J, Xiong H. Characteristics of spatial protein expression in the mouse cochlear sensory epithelia: Implications for age-related hearing loss. Hear Res 2024; 446:109006. [PMID: 38583350 DOI: 10.1016/j.heares.2024.109006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/27/2024] [Accepted: 04/01/2024] [Indexed: 04/09/2024]
Abstract
Hair cells in the cochlear sensory epithelia serve as mechanosensory receptors, converting sound into neuronal signals. The basal sensory epithelia are responsible for transducing high-frequency sounds, while the apex handles low-frequency sounds. Age-related hearing loss predominantly affects hearing at high frequencies and is indicative of damage to the basal sensory epithelia. However, the precise mechanism underlying this site-selective injury remains unclear. In this study, we employed a microscale proteomics approach to examine and compare protein expression in different regions of the cochlear sensory epithelia (upper half and lower half) in 1.5-month-old (normal hearing) and 6-month-old (severe high-frequency hearing loss without hair cell loss) C57BL/6J mice. A total of 2,386 proteins were detected, and no significant differences in protein expression were detected in the upper half of the cochlear sensory epithelia between the two age groups. The expression of 20 proteins in the lower half of the cochlear sensory epithelia significantly differed between the two age groups (e.g., MATN1, MATN4, and AQP1). Moreover, there were 311 and 226 differentially expressed proteins between the upper and lower halves of the cochlear sensory epithelia in 1.5-month-old and 6-month-old mice, respectively. The expression levels of selected proteins were validated by Western blotting. These findings suggest that the spatial differences in protein expression within the cochlear sensory epithelia may play a role in determining the susceptibility of cells at different sites of the cochlea to age-related damage.
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Affiliation(s)
- Huilin Lao
- Department of Otolaryngology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, Guangzhou, China
| | - Yafeng Zhu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Mei Yang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Lingshuo Wang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Jie Tang
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China; Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China.
| | - Hao Xiong
- Department of Otolaryngology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, Guangzhou, China.
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Bauer MA, Bazard P, Acosta AA, Bangalore N, Elessaway L, Thivierge M, Chellani M, Zhu X, Ding B, Walton JP, Frisina RD. L-Ergothioneine slows the progression of age-related hearing loss in CBA/CaJ mice. Hear Res 2024; 446:109004. [PMID: 38608332 PMCID: PMC11112832 DOI: 10.1016/j.heares.2024.109004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 03/25/2024] [Accepted: 04/01/2024] [Indexed: 04/14/2024]
Abstract
The naturally occurring amino acid, l-ergothioneine (EGT), has immense potential as a therapeutic, having shown promise in the treatment of other disease models, including neurological disorders. EGT is naturally uptaken into cells via its specific receptor, OCTN1, to be utilized by cells as an antioxidant and anti-inflammatory. In our current study, EGT was administered over a period of 6 months to 25-26-month-old CBA/CaJ mice as a possible treatment for age-related hearing loss (ARHL), since presbycusis has been linked to higher levels of cochlear oxidative stress, apoptosis, and chronic inflammation. Results from the current study indicate that EGT can prevent aging declines of some key features of ARHL. However, we found a distinct sex difference for the response to the treatments, for hearing - Auditory Brainstem Responses (ABRs) and Distortion Product Otoacoustic Emissions (DPOAEs). Males exhibited lower threshold declines in both low dose (LD) and high dose (HD) test groups throughout the testing period and did not display some of the characteristic aging declines in hearing seen in Control animals. In contrast, female mice did not show any therapeutic effects with either treatment dose. Further confirming this sex difference, EGT levels in whole blood sampling throughout the testing period showed greater uptake of EGT in males compared to females. Additionally, RT-PCR results from three tissue types of the inner ear confirmed EGT activity in the cochlea in both males and females. Males and females exhibited significant differences in biomarkers related to apoptosis (Cas-3), inflammation (TNF-a), oxidative stress (SOD2), and mitochondrial health (PGC1a).These changes were more prominent in males as compared to females, especially in stria vascularis tissue. Taken together, these findings suggest that EGT has the potential to be a naturally derived therapeutic for slowing down the progression of ARHL, and possibly other neurodegenerative diseases. EGT, while effective in the treatment of some features of presbycusis in aging males, could also be modified into a general prophylaxis for other age-related disorders where treatment protocols would include eating a larger proportion of EGT-rich foods or supplements. Lastly, the sex difference discovered here, needs further investigation to see if therapeutic conditions can be developed where aging females show better responsiveness to EGT.
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Affiliation(s)
- Mark A Bauer
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Parveen Bazard
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA.
| | - Alejandro A Acosta
- School of Medicine, University of Puerto Rico, San Juan, 00925 Puerto Rico; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Nidhi Bangalore
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Lina Elessaway
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Biomedical Sciences - Dept. of Chemistry, University of South Florida, Tampa, FL 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Mark Thivierge
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Moksheta Chellani
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Xiaoxia Zhu
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Bo Ding
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Joseph P Walton
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Department Communication Sciences and Disorders, College of Behavioral & Community Sciences, Tampa, FL 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Robert D Frisina
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA; Department Communication Sciences and Disorders, College of Behavioral & Community Sciences, Tampa, FL 33620, USA; Morsani College of Medicine, University of South Florida, Tampa, FL 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA.
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5
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Jiang K, Wang T, Huang X, Gao L. Identification of mRNA expression profiles and their characterization in age-related hearing loss. Cell Mol Biol (Noisy-le-grand) 2024; 70:255-259. [PMID: 38678595 DOI: 10.14715/cmb/2024.70.4.40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Indexed: 05/01/2024]
Abstract
Age-related hearing loss (ARHL), is a pervasive health problem worldwide. ARHL seriously affects the quality of life and reportedly leads to social isolation and dementia in the elderly. ARHL is caused by the degeneration or disorders of cochlear hair cells and auditory neurons. Numerous studies have verified that genetic factors contributed to this impairment, however, the mechanism behind remains unclear. In this study, we analyzed an mRNA expression dataset (GSE49543) from the GEO database. Differentially expressed genes (DEGs) between young control mice and presbycusis mice were analyzed using limma in R and weighted gene co-expression network analysis (WGCNA) methods. Functional enrichment analyses of the DEGs were conducted with the clusterProfiler R package and the results were visualized using ggplot2 R package. The STRING database was used for the construction of the protein-protein interaction (PPI) network of the screened DEGs. Two machine learning algorithms LASSO and SVM-RFE were used to screen the hub genes. We identified 54 DEGs in presbycusis using limma and WGCNA. DEGs were associated with the synaptic vesicle cycle, distal axon, neurotransmitter transmembrane transporter activity in GO analysis, and alcoholic liver disease, pertussis, lysosome pathway according to KEGG analyses. PPI network analysis identified three significant modules. Five hub genes (CLEC4D, MS4A7, CTSS, LAPTM5, ALOX5AP) were screened by LASSO and SVM-RFE. These hub genes were highly expressed in presbycusis mice compared with young control mice. We screened DEGs and identified hub genes involved in ARHL development, which might provide novel clues to understanding the molecular basis of ARHL.
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Affiliation(s)
- Kanglun Jiang
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai 200030, China.
| | - Tan Wang
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai 200030, China.
| | - Xinsheng Huang
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai 200030, China.
| | - Li Gao
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai 200030, China.
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Pineros J, Zhu X, Ding B, Frisina RD. Connexins 30 and 43 expression changes in relation to age-related hearing loss. Hear Res 2024; 444:108971. [PMID: 38359484 PMCID: PMC10939722 DOI: 10.1016/j.heares.2024.108971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/27/2024] [Accepted: 02/10/2024] [Indexed: 02/17/2024]
Abstract
Age-related hearing loss (ARHL), also known as presbycusis, is the number one communication disorder for aging adults. Connexin proteins are essential for intercellular communication throughout the human body, including the cochlea. Mutations in connexin genes have been linked to human syndromic and nonsyndromic deafness; thus, we hypothesize that changes in connexin gene and protein expression with age are involved in the etiology of ARHL. Here, connexin gene and protein expression changes for CBA/CaJ mice at different ages were examined, and correlations were analyzed between the changes in expression levels and functional hearing measures, such as ABRs and DPOAEs. Moreover, we investigated potential treatment options for ARHL. Results showed significant downregulation of Cx30 and Cx43 gene expression and significant correlations between the degree of hearing loss and the changes in gene expression for both genes. Moreover, dose-dependent treatments utilizing cochlear cell lines showed that aldosterone hormone therapy significantly increased Cx expression. In vivo mouse treatments with aldosterone also showed protective effects on connexin expression in aging mice. Based on these functionally relevant findings, next steps can include more investigations of the mechanisms related to connexin family gap junction protein expression changes during ARHL; and expand knowledge of clinically-relevant treatment options by knowing what specific members of the Cx family and related inter-cellular proteins should be targeted therapeutically.
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Affiliation(s)
- Jennifer Pineros
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Xiaoxia Zhu
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Bo Ding
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Robert D Frisina
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA; Department of Communication Sciences and Disorders, College of Behavioral & Community Sciences, University of South Florida, Tampa, FL 33620, USA; Morsani College of Medicine, University of South Florida, Tampa, FL 33620, USA.
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Xu K, Chen S, Bai X, Xie L, Qiu Y, Liu X, Wang X, Kong W, Sun Y. Degradation of cochlear Connexin26 accelerate the development of age-related hearing loss. Aging Cell 2023; 22:e13973. [PMID: 37681746 PMCID: PMC10652327 DOI: 10.1111/acel.13973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/03/2023] [Accepted: 08/15/2023] [Indexed: 09/09/2023] Open
Abstract
The GJB2 gene, encoding Connexin26 (Cx26), is one of the most common causes of inherited deafness. Clinically, mutations in GJB2 cause congenital deafness or late-onset progressive hearing loss. Recently, it has been reported that Cx26 haploid deficiency accelerates the development of age-related hearing loss (ARHL). However, the roles of cochlear Cx26 in the hearing function of aged animals remain unclear. In this study, we revealed that the Cx26 expression was significantly reduced in the cochleae of aged mice, and further explored the underlying molecular mechanism for Cx26 degradation. Immunofluorescence co-localization results showed that Cx26 was internalized and degraded by lysosomes, which might be one of the important ways for Cx26 degradation in the cochlea of aged mice. Currently, whether the degradation of Cx26 in the cochlea leads directly to ARHL, as well as the mechanism of Cx26 degradation-related hearing loss are still unclear. To address these questions, we generated mice with Cx26 knockout in the adult cochlea as a model for the natural degradation of Cx26. Auditory brainstem response (ABR) results showed that Cx26 knockout mice exhibited high-frequency hearing loss, which gradually progressed over time. Pathological examination also revealed the degeneration of hair cells and spiral ganglions, which is similar to the phenotype of ARHL. In summary, our findings suggest that degradation of Cx26 in the cochlea accelerates the occurrence of ARHL, which may be a novel mechanism of ARHL.
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Affiliation(s)
- Kai Xu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Sen Chen
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Xue Bai
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Le Xie
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Yue Qiu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Xiao‐zhou Liu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Xiao‐hui Wang
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Wei‐jia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Yu Sun
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and RegenerationWuhanChina
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Liu Y, Zhang H, Fan C, Liu F, Li S, Li J, Zhao H, Zeng X. Potential role of Bcl2 in lipid metabolism and synaptic dysfunction of age-related hearing loss. Neurobiol Dis 2023; 187:106320. [PMID: 37813166 DOI: 10.1016/j.nbd.2023.106320] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/25/2023] [Accepted: 10/06/2023] [Indexed: 10/11/2023] Open
Abstract
Age-related hearing loss (ARHL) is a prevalent condition affecting millions of individuals globally. This study investigated the role of the cell survival regulator Bcl2 in ARHL through in vitro and in vivo experiments and metabolomics analysis. The results showed that the lack of Bcl2 in the auditory cortex affects lipid metabolism, resulting in reduced synaptic function and neurodegeneration. Immunohistochemical analysis demonstrated enrichment of Bcl2 in specific areas of the auditory cortex, including the secondary auditory cortex, dorsal and ventral areas, and primary somatosensory cortex. In ARHL rats, a significant decrease in Bcl2 expression was observed in these areas. RNAseq analysis showed that the downregulation of Bcl2 altered lipid metabolism pathways within the auditory pathway, which was further confirmed by metabolomics analysis. These results suggest that Bcl2 plays a crucial role in regulating lipid metabolism, synaptic function, and neurodegeneration in ARHL; thereby, it could be a potential therapeutic target. We also revealed that Bcl2 probably has a close connection with lipid peroxidation and reactive oxygen species (ROS) production occurring in cochlear hair cells and cortical neurons in ARHL. The study also identified changes in hair cells, spiral ganglion cells, and nerve fiber density as consequences of Bcl2 deficiency, which could potentially contribute to the inner ear nerve blockage and subsequent hearing loss. Therefore, targeting Bcl2 may be a promising potential therapeutic intervention for ARHL. These findings provide valuable insights into the molecular mechanisms underlying ARHL and may pave the way for novel treatment approaches for this prevalent age-related disorder.
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Affiliation(s)
- Yue Liu
- Department of Graduate and Scientific Research, Zunyi Medical University Zhuhai Campus, Zhuhai 519041, China; Department of Otolaryngology, Longgang E.N.T Hospital & Shenzhen Key Laboratory of E.N.T, Institute of E.N.T, Shenzhen 518172, China.
| | - Huasong Zhang
- Department of Otolaryngology, Longgang E.N.T Hospital & Shenzhen Key Laboratory of E.N.T, Institute of E.N.T, Shenzhen 518172, China; Department of Otolaryngology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510000, China; Department of Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangzhou, 510000, China.
| | - Cong Fan
- Department of Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangzhou, 510000, China
| | - Feiyi Liu
- Department of Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangzhou, 510000, China
| | - Shaoying Li
- Department of Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangzhou, 510000, China
| | - Juanjuan Li
- Department of Otolaryngology, Longgang E.N.T Hospital & Shenzhen Key Laboratory of E.N.T, Institute of E.N.T, Shenzhen 518172, China
| | - Huiying Zhao
- Department of Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangzhou, 510000, China
| | - Xianhai Zeng
- Department of Graduate and Scientific Research, Zunyi Medical University Zhuhai Campus, Zhuhai 519041, China; Department of Otolaryngology, Longgang E.N.T Hospital & Shenzhen Key Laboratory of E.N.T, Institute of E.N.T, Shenzhen 518172, China.
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Luo X, Hu Y, Zhou X, Zhang C, Feng M, Yang T, Yuan W. Potential roles for lncRNA Mirg/Foxp1 in an ARHL model created using C57BL/6J mice. Hear Res 2023; 438:108859. [PMID: 37579646 DOI: 10.1016/j.heares.2023.108859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 07/21/2023] [Accepted: 08/07/2023] [Indexed: 08/16/2023]
Abstract
Age-related hearing loss (ARHL) is associated with hair cell apoptosis, but the underlying mechanism of hair cell apoptosis remains unclear. Here, we investigated the expression profiles of long noncoding RNAs (lncRNAs) and mRNAs in an ARHL model created with C57BL/6 J mice using RNA sequencing and found that the expression of several lncRNAs was significantly correlated with apoptosis-associated mRNAs in the cochlear tissues of old mice compared to young mice. We found that lncRNA Mirg was upregulated in the cochlear tissues of old mice compared to young mice and its overexpression promoted apoptosis in House Ear Institute-Organ of Corti 1 (HEI-OC1). H2O2-induced oxidative stress increased HEI-OC1 cell apoptosis by upregulating lncRNA Mirg. Furthermore, the expression of lncRNA Mirg and Foxp1 showed the highest correlation coefficient in the cochlear tissues of old mice, and lncRNA Mirg promoted HEI-OC1 cell apoptosis by increasing Foxp1 expression. In conclusion, our findings suggest that lncRNA Mirg expression correlates with cell apoptosis-associated mRNAs in the ARHL model created using C57BL/6 J mice and that oxidative stress-induced lncRNA Mirg promotes HEI-OC1 cell apoptosis by increasing Foxp1 expression. These data suggest the potential therapeutic significance of targeting lncRNA Mirg/Foxp1 signaling in ARHL.
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Affiliation(s)
- Xiaoqin Luo
- Department of Otolaryngology, Chongqing Medical University, Chongqing, 400042, China; Chongqing Institute of Green and Intelligent Technology, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing General Hospital, Chongqing 400014, China
| | - Yaqin Hu
- Department of Otolaryngology, Chongqing Medical University, Chongqing, 400042, China; Chongqing Institute of Green and Intelligent Technology, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing General Hospital, Chongqing 400014, China
| | - Xiaoqing Zhou
- Department of Otolaryngology, Chongqing Medical University, Chongqing, 400042, China; Chongqing Institute of Green and Intelligent Technology, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing General Hospital, Chongqing 400014, China
| | - Chanyuan Zhang
- Department of Otolaryngology, Chongqing Medical University, Chongqing, 400042, China; Chongqing Institute of Green and Intelligent Technology, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing General Hospital, Chongqing 400014, China
| | - Menglong Feng
- Department of Otolaryngology, Chongqing Medical University, Chongqing, 400042, China; Chongqing Institute of Green and Intelligent Technology, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing General Hospital, Chongqing 400014, China
| | - Ting Yang
- Department of Otolaryngology, Chongqing Medical University, Chongqing, 400042, China; Chongqing Institute of Green and Intelligent Technology, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing General Hospital, Chongqing 400014, China
| | - Wei Yuan
- Department of Otolaryngology, Chongqing Medical University, Chongqing, 400042, China; Chongqing Institute of Green and Intelligent Technology, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China; Department of Otolaryngology, Chongqing General Hospital, Chongqing 400014, China.
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10
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Pham TB, Boussaty EC, Currais A, Maher P, Schubert DR, Manor U, Friedman RA. Attenuation of Age-Related Hearing Impairment in Senescence-Accelerated Mouse Prone 8 (SAMP8) Mice Treated with Fatty Acid Synthase Inhibitor CMS121. J Mol Neurosci 2023; 73:307-315. [PMID: 37097512 PMCID: PMC10200781 DOI: 10.1007/s12031-023-02119-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 04/17/2023] [Indexed: 04/26/2023]
Abstract
In the senescence-accelerated mouse prone 8 (SAMP8) mouse model, oxidative stress leads to premature senescence and age-related hearing impairment (ARHI). CMS121 inhibits oxytosis/ferroptosis by targeting fatty acid synthase. The aim of our study was to determine whether CMS121 is protective against ARHI in SAMP8 mice. Auditory brainstem responses (ABRs) were used to assess baseline hearing in sixteen 4-week-old female SAMP8 mice, which were divided into two cohorts. The control group was fed a vehicle diet, while the experimental group was fed a diet containing CMS121. ABRs were measured until 13 weeks of age. Cochlear immunohistochemistry was performed to analyze the number of paired ribbon-receptor synapses per inner hair cell (IHC). Descriptive statistics are provided with mean ± SEM. Two-sample t-tests were performed to compare hearing thresholds and paired synapse count across the two groups, with alpha = 0.05. Baseline hearing thresholds in the control group were statistically similar to those of the CMS121 group. At 13 weeks of age, the control group had significantly worse hearing thresholds at 12 kHz (56.5 vs. 39.8, p = 0.044) and 16 kHz (64.8 vs. 43.8, p = 0.040) compared to the CMS121 group. Immunohistochemistry showed a significantly lower synapse count per IHC in the control group (15.7) compared to the CMS121 group (18.4), p = 0.014. Our study shows a significant reduction in ABR threshold shifts and increased preservation of IHC ribbon synapses in the mid-range frequencies among mice treated with CMS121 compared to untreated mice.
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Affiliation(s)
- Tammy B Pham
- Department of Otolaryngology-Head and Neck Surgery, University of California San Diego Health, 92037, La Jolla, CA, USA
| | - Ely Cheikh Boussaty
- Department of Otolaryngology-Head and Neck Surgery, University of California San Diego Health, 92037, La Jolla, CA, USA
| | - Antonio Currais
- Cellular Neurobiology Laboratory, Salk Institute for Biological Studies, 92037, La Jolla, CA, USA
| | - Pamela Maher
- Cellular Neurobiology Laboratory, Salk Institute for Biological Studies, 92037, La Jolla, CA, USA
| | - David R Schubert
- Cellular Neurobiology Laboratory, Salk Institute for Biological Studies, 92037, La Jolla, CA, USA
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 92037, La Jolla, CA, USA
| | - Rick A Friedman
- Department of Otolaryngology-Head and Neck Surgery, University of California San Diego Health, 92037, La Jolla, CA, USA.
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11
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Salam SA, Mostafa F, Alnamshan MM, Elshewemi SS, Sorour JM. Thymoquinone ameliorates age-related hearing loss in C57BL/6J mice by modulating Sirt1 activity and Bak1 expression. Biomed Pharmacother 2021; 143:112149. [PMID: 34507120 DOI: 10.1016/j.biopha.2021.112149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/27/2021] [Accepted: 08/31/2021] [Indexed: 01/10/2023] Open
Abstract
Age-related hearing loss (AHL) is the most common sensory disorder of aged population. Currently, one of the most important sources of experimental medicine for AHL is medicinal plants. This study performed the first investigation of the effect of thymoquinone (TQ), a potent antioxidant, on AHL. Here, we used inbred C57BL/6J mice (B6 mice) as a successful experimental model of the early onset of AHL. The behavioral assessment of hearing revealed that the injection of a high dose of TQ (40 mg/kg; TQ40) significantly improved the auditory sensitivity of B6 mice at all tested frequencies (8, 16 and 22 kHz). Histological sections of cochlea from B6 mice injected with a low dose (20 mg/kg; TQ20) and high dose showed relatively less degenerative signs in the modiolus, hair cells and spiral ligaments, the main constituents of the cochlea. In addition, TQ40 completely restored the normal pattern of hair cells in B6 mice, as shown in scanning electron micrographs. Our data indicated that TQ20 and TQ40 reduced levels of Bak1-mediated apoptosis in the cochlea of B6 mice. Interestingly, the level of Sirt1, a positive regulator of autophagy, was significantly increased in B6 mice administered TQ40. In conclusion, TQ relieves the symptoms of AHL by downregulating Bak1 and activating Sirt1 in the cochlea of B6 mice.
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Affiliation(s)
- Sherine Abdel Salam
- Department of Zoology, Faculty of Science, Alexandria University, Alexandria 21511, Egypt.
| | - Fatma Mostafa
- Department of Zoology, Faculty of Science, Alexandria University, Alexandria 21511, Egypt.
| | - Mashael M Alnamshan
- Department of Biology, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia.
| | - Salma S Elshewemi
- Department of Zoology, Faculty of Science, Alexandria University, Alexandria 21511, Egypt.
| | - Jehan M Sorour
- Department of Zoology, Faculty of Science, Alexandria University, Alexandria 21511, Egypt.
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Uraguchi K, Maeda Y, Takahara J, Omichi R, Fujimoto S, Kariya S, Nishizaki K, Ando M. Upregulation of a nuclear factor-kappa B-interacting immune gene network in mice cochleae with age-related hearing loss. PLoS One 2021; 16:e0258977. [PMID: 34679122 PMCID: PMC8535356 DOI: 10.1371/journal.pone.0258977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 10/09/2021] [Indexed: 12/15/2022] Open
Abstract
Epidemiological data suggest that inflammation and innate immunity play significant roles in the pathogenesis of age-related hearing loss (ARHL) in humans. In this mouse study, real-time RT-PCR array targeting 84 immune-related genes revealed that the expressions of 40 genes (47.6%) were differentially regulated with greater than a twofold change in 12-month-old cochleae with ARHL relative to young control mice, 33 (39.3%) of which were upregulated. These differentially regulated genes (DEGs) were involved in functional pathways for cytokine–cytokine receptor interaction, chemokine signaling, TNF signaling, and Toll-like receptor signaling. An NF-κB subunit, Nfkb1, was upregulated in aged cochleae, and bioinformatic analyses predicted that NF-κB would interact with the genomic regulatory regions of eight upregulated DEGs, including Tnf and Ptgs2. In aging cochleae, major proinflammatory molecules, IL1B and IL18rap, were upregulated by 6 months of age and thereafter. Remarkable upregulations of seven immune-related genes (Casp1, IL18r1, IL1B, Card9, Clec4e, Ifit1, and Tlr9) occurred at an advanced stage (between 9 and 12 months of age) of ARHL. Immunohistochemistry analysis of cochlear sections from the 12-month-old mice indicated that IL-18r1 and IL-1B were localized to the spiral ligament, spiral limbus, and organ of Corti. The two NF-κB-interacting inflammatory molecules, TNFα and PTGS2, immunolocalized ubiquitously in cochlear structures, including the lateral wall (the stria vascularis and spiral ligament), in the histological sections of aged cochleae. IBA1-positive macrophages were observed in the stria vascularis and spiral ligament in aged mice. Therefore, inflammatory and immune reactions are modulated in aged cochlear tissues with ARHL.
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Affiliation(s)
- Kensuke Uraguchi
- Department of Otolaryngology- Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Yukihide Maeda
- Department of Otolaryngology- Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- * E-mail:
| | - Junko Takahara
- Department of Otolaryngology- Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Ryotaro Omichi
- Department of Otolaryngology- Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Shohei Fujimoto
- Department of Otolaryngology- Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Shin Kariya
- Department of Otolaryngology- Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Kazunori Nishizaki
- Department of Otolaryngology- Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Mizuo Ando
- Department of Otolaryngology- Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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13
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Bazard P, Frisina RD, Acosta AA, Dasgupta S, Bauer MA, Zhu X, Ding B. Roles of Key Ion Channels and Transport Proteins in Age-Related Hearing Loss. Int J Mol Sci 2021; 22:6158. [PMID: 34200434 PMCID: PMC8201059 DOI: 10.3390/ijms22116158] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 12/25/2022] Open
Abstract
The auditory system is a fascinating sensory organ that overall, converts sound signals to electrical signals of the nervous system. Initially, sound energy is converted to mechanical energy via amplification processes in the middle ear, followed by transduction of mechanical movements of the oval window into electrochemical signals in the cochlear hair cells, and finally, neural signals travel to the central auditory system, via the auditory division of the 8th cranial nerve. The majority of people above 60 years have some form of age-related hearing loss, also known as presbycusis. However, the biological mechanisms of presbycusis are complex and not yet fully delineated. In the present article, we highlight ion channels and transport proteins, which are integral for the proper functioning of the auditory system, facilitating the diffusion of various ions across auditory structures for signal transduction and processing. Like most other physiological systems, hearing abilities decline with age, hence, it is imperative to fully understand inner ear aging changes, so ion channel functions should be further investigated in the aging cochlea. In this review article, we discuss key various ion channels in the auditory system and how their functions change with age. Understanding the roles of ion channels in auditory processing could enhance the development of potential biotherapies for age-related hearing loss.
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Affiliation(s)
- Parveen Bazard
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Robert D. Frisina
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
- Department Communication Sciences and Disorders, College of Behavioral & Communication Sciences, Tampa, FL 33620, USA
| | - Alejandro A. Acosta
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Sneha Dasgupta
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Mark A. Bauer
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Xiaoxia Zhu
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Bo Ding
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
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14
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Golub JS, Sharma RK, Rippon BQ, Brickman AM, Luchsinger JA. The Association Between Early Age-Related Hearing Loss and Brain β-Amyloid. Laryngoscope 2021; 131:633-638. [PMID: 32644260 PMCID: PMC7794089 DOI: 10.1002/lary.28859] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/12/2020] [Accepted: 05/18/2020] [Indexed: 11/09/2022]
Abstract
OBJECTIVES/HYPOTHESIS To analyze the association between early audiometric age-related hearing loss and brain β-amyloid, the pathologic hallmark of Alzheimer's disease (AD). STUDY DESIGN Cross-sectional analysis of a prospective cohort study. METHODS A cross-sectional analysis was performed on 98 participants in a cohort study of hearing and brain biomarkers of AD. The primary outcome was whole brain β-amyloid standardized uptake value ratio (SUVR) on positron emission tomography (PET). The exposure was hearing, as measured by either pure-tone average or word recognition score in the better ear. Covariates included age, gender, education, cardiovascular disease, and hearing aid use. Linear regression was performed to analyze the association between β-amyloid and hearing, adjusting for potentially confounding covariates. RESULTS The mean age ± standard deviation was 64.6 ± 3.5 years. In multivariable regression, adjusting for demographics, education, cardiovascular disease, and hearing aid use, whole brain β-amyloid SUVR increased by 0.029 (95% confidence interval [CI]: 0.003-0.056) for every 10 dB increase in pure-tone average (P = .030). Similarly, whole brain β-amyloid SUVR increased by 0.061 (95% CI: 0.009-0.112) for every 10% increase in word recognition score (P = .012). CONCLUSIONS Worsening hearing was associated with higher β-amyloid burden, a pathologic hallmark of AD, measured in vivo with PET scans. LEVEL OF EVIDENCE 3 Laryngoscope, 131:633-638, 2021.
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Affiliation(s)
- Justin S. Golub
- Department of Otolaryngology—Head and Neck Surgery, Columbia University, New York, NY, USA
| | - Rahul K. Sharma
- Department of Otolaryngology—Head and Neck Surgery, Columbia University, New York, NY, USA
| | - Brady Q. Rippon
- Department of Medicine, Columbia University, New York, NY, USA
| | - Adam M. Brickman
- Department of Neurology, the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, and the Gertrude H. Sergievsky Center; Vagelos College of Physicians and Surgeons, NewYork-Presbyterian/Columbia University Irving Medical Center, Columbia University, New York, NY, USA
| | - José A. Luchsinger
- Department of Medicine, Columbia University, New York, NY, USA
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
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15
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Zhao J, Li G, Zhao X, Lin X, Gao Y, Raimundo N, Li GL, Shang W, Wu H, Song L. Down-regulation of AMPK signaling pathway rescues hearing loss in TFB1 transgenic mice and delays age-related hearing loss. Aging (Albany NY) 2020; 12:5590-5611. [PMID: 32240104 PMCID: PMC7185105 DOI: 10.18632/aging.102977] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 03/03/2020] [Indexed: 04/08/2023]
Abstract
AMP-activated protein kinase (AMPK) integrates the regulation of cell growth and metabolism. AMPK activation occurs in response to cellular energy decline and mitochondrial dysfunction triggered by reactive oxygen species (ROS). In aged Tg-mtTFB1 mice, a mitochondrial deafness mouse model, hearing loss is accompanied with cochlear pathology including reduced endocochlear potential (EP) and loss of spiral ganglion neurons (SGN), inner hair cell (IHC) synapses and outer hair cells (OHC). Accumulated ROS and increased apoptosis signaling were also detected in cochlear tissues, accompanied by activation of AMPK. To further explore the role of AMPK signaling in the auditory phenotype, we used genetically knocked out AMPKα1 as a rescue to Tg-mtTFB1 mice and observed: improved ABR wave I, EP and IHC function, normal SGNs, IHC synapses morphology and OHC survivals, with decreased ROS, reduced pro-apoptotic signaling (Bax) and increased anti-apoptotic signaling (Bcl-2) in the cochlear tissues, indicating that reduced AMPK attenuated apoptosis via ROS-AMPK-Bcl2 pathway in the cochlea. To conclude, AMPK hyperactivation causes accelerated presbycusis in Tg-mtTFB1 mice by redox imbalance and dysregulation of the apoptosis pathway. The effects of AMPK downregulation on pro-survival function and reduction of oxidative stress indicate AMPK serves as a target to rescue or relieve mitochondrial hearing loss.
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Affiliation(s)
- Jingjing Zhao
- Department of Otolaryngology, Head and Neck Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Gen Li
- Department of Otolaryngology, Head and Neck Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Xuan Zhao
- Navy Clinical Medical School, Anhui Medical University, Hefei, China
| | - Xin Lin
- Department of Otorhinolaryngology, Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yunge Gao
- Department of Otolaryngology, Head and Neck Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Nuno Raimundo
- Institute of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Geng-Lin Li
- Department of Otorhinolaryngology, Eye and ENT Hospital, Fudan University, Shanghai, China
| | - Wei Shang
- Navy Clinical Medical School, Anhui Medical University, Hefei, China
- In Vitro Fertility (IVF) Center Department of Obstetrics and Gynecology, the Sixth Medical Center of PLA General Hospital, Beijing, China
| | - Hao Wu
- Department of Otolaryngology, Head and Neck Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Lei Song
- Department of Otolaryngology, Head and Neck Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
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16
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Li Y, Zhao X, Hu Y, Sun H, He Z, Yuan J, Cai H, Sun Y, Huang X, Kong W, Kong W. Age-associated decline in Nrf2 signaling and associated mtDNA damage may be involved in the degeneration of the auditory cortex: Implications for central presbycusis. Int J Mol Med 2018; 42:3371-3385. [PMID: 30272261 PMCID: PMC6202109 DOI: 10.3892/ijmm.2018.3907] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 09/19/2018] [Indexed: 11/15/2022] Open
Abstract
Central presbycusis is the most common sensory disorder in the elderly population, however, the underlying molecular mechanism remains unclear. NF‑E2‑related factor 2 (Nrf2) is a key transcription factor in the cellular response to oxidative stress, however, the role of Nrf2 in central presbycusis remains to be elucidated. The aim of the present study was to investigate the pathogenesis of central presbycusis using a mimetic aging model induced by D‑galactose (D‑gal) in vivo and in vitro. The degeneration of the cell was determined with transmission electron microscopy, terminal deoxynucleotidyl transferase‑mediated deoxyuridine 5'‑triphosphate nick‑end labeling staining, and senescence‑associated β‑galactosidase staining. The expression of protein was detected by western blotting and immunofluorescence. The quantification of the mitochondrial DNA (mtDNA) 4,834‑base pair (bp) deletion and mRNA was detected by TaqMan quantitative polymerase chain reaction (qPCR) and reverse transcription‑qPCR respectively. Cell apoptosis and intracellular ROS in vitro were determined with flow cytometry. The levels of nuclear Nrf2, and the mRNA levels of Nrf2‑regulated antioxidant genes, were downregulated in the auditory cortex of aging rats, which was accompanied by an increase in 8‑hydroxy‑2'‑deoxyguanosine formation, an accumulation of mtDNA 4,834‑bp deletion, and neuron degeneration. In addition, oltipraz, a typical Nrf2 activator, was found to protect cells against D‑gal‑induced mtDNA damage and mitochondrial dysfunction by activating Nrf2 target genes in vitro. It was also observed that activating Nrf2 with oltipraz inhibited cell apoptosis and delayed senescence. Taken together, the data of the present study suggested that the age‑associated decline in Nrf2 signaling activity and the associated mtDNA damage in the auditory cortex may be implicated in the degeneration of the auditory cortex. Therefore, the restoration of Nrf2 signaling activity may represent a potential therapeutic strategy for central presbycusis.
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Affiliation(s)
| | | | | | | | | | | | - Hua Cai
- Department of Otolaryngology
| | - Yu Sun
- Department of Otolaryngology
| | | | - Wen Kong
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
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Fetoni AR, Zorzi V, Paciello F, Ziraldo G, Peres C, Raspa M, Scavizzi F, Salvatore AM, Crispino G, Tognola G, Gentile G, Spampinato AG, Cuccaro D, Guarnaccia M, Morello G, Van Camp G, Fransen E, Brumat M, Girotto G, Paludetti G, Gasparini P, Cavallaro S, Mammano F. Cx26 partial loss causes accelerated presbycusis by redox imbalance and dysregulation of Nfr2 pathway. Redox Biol 2018; 19:301-317. [PMID: 30199819 PMCID: PMC6129666 DOI: 10.1016/j.redox.2018.08.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/26/2018] [Accepted: 08/05/2018] [Indexed: 11/29/2022] Open
Abstract
Mutations in GJB2, the gene that encodes connexin 26 (Cx26), are the most common cause of sensorineural hearing impairment. The truncating variant 35delG, which determines a complete loss of Cx26 protein function, is the prevalent GJB2 mutation in several populations. Here, we generated and analyzed Gjb2+/- mice as a model of heterozygous human carriers of 35delG. Compared to control mice, auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs) worsened over time more rapidly in Gjb2+/- mice, indicating they were affected by accelerated age-related hearing loss (ARHL), or presbycusis. We linked causally the auditory phenotype of Gjb2+/- mice to apoptosis and oxidative damage in the cochlear duct, reduced release of glutathione from connexin hemichannels, decreased nutrient delivery to the sensory epithelium via cochlear gap junctions and deregulated expression of genes that are under transcriptional control of the nuclear factor erythroid 2-related factor 2 (Nrf2), a pivotal regulator of tolerance to redox stress. Moreover, a statistically significant genome-wide association with two genes (PRKCE and TGFB1) related to the Nrf2 pathway (p-value < 4 × 10-2) was detected in a very large cohort of 4091 individuals, originating from Europe, Caucasus and Central Asia, with hearing phenotype (including 1076 presbycusis patients and 1290 healthy matched controls). We conclude that (i) elements of the Nrf2 pathway are essential for hearing maintenance and (ii) their dysfunction may play an important role in the etiopathogenesis of human presbycusis.
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Affiliation(s)
- Anna Rita Fetoni
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy; Institute of Otolaryngology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo F. Vito 1, 00168 Rome, Italy
| | - Veronica Zorzi
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy
| | - Fabiola Paciello
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy
| | - Gaia Ziraldo
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy
| | - Chiara Peres
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy
| | - Marcello Raspa
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy
| | | | | | - Giulia Crispino
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy
| | - Gabriella Tognola
- CNR Institute of Electronics, Computer and Telecommunication Engineering, 20133 Milano, Italy
| | - Giulia Gentile
- CNR Institute of Neurological Sciences, 95126 Catania, Italy
| | | | - Denis Cuccaro
- CNR Institute of Neurological Sciences, 95126 Catania, Italy
| | | | | | - Guy Van Camp
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Universiteitsplein 1, 2610 Antwerp, Belgium
| | - Erik Fransen
- Department of Biomedical Sciences, University of Antwerp, 2650 Antwerp, Belgium
| | - Marco Brumat
- Dept Med Surg & Hlth Sci, University of Trieste, Trieste, Italy; IRCCS Burlo Garofolo, Inst Maternal & Child Hlth, Trieste, Italy
| | - Giorgia Girotto
- Dept Med Surg & Hlth Sci, University of Trieste, Trieste, Italy; IRCCS Burlo Garofolo, Inst Maternal & Child Hlth, Trieste, Italy
| | - Gaetano Paludetti
- Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy; Institute of Otolaryngology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo F. Vito 1, 00168 Rome, Italy
| | - Paolo Gasparini
- Dept Med Surg & Hlth Sci, University of Trieste, Trieste, Italy; IRCCS Burlo Garofolo, Inst Maternal & Child Hlth, Trieste, Italy.
| | | | - Fabio Mammano
- CNR Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy; University of Padova, Department of Physics and Astronomy "G. Galilei", Padova, Italy.
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Sánchez-Rodríguez C, Cuadrado E, Riestra-Ayora J, Sanz-Fernández R. Polyphenols protect against age-associated apoptosis in female rat cochleae. Biogerontology 2018; 19:159-169. [PMID: 29363005 DOI: 10.1007/s10522-018-9747-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/18/2018] [Indexed: 01/13/2023]
Abstract
Dietary antioxidants, polyphenols, have been found to be beneficial in protecting against the generation of oxidative stress in various diseases associated with aging. Age-related hearing loss (AHL) is the number one neurodegenerative disorder on our aged population. Sprague-Dawley rats divided into five groups according to their age (3, 6, 12, 18 and 24 months old) and treated with 100 mg/day/kg body weight of polyphenols were used. Then, cochleae were harvested to measure caspase activities (- 3, - 8 and - 9), caspase-3 gene expression, ATP levels, Bax, BcL-2 and p53 levels. 8-OHdG levels (marker of DNA oxidative damage) and annexin-V were also measured in cochleae. Increased levels of caspase-3 and 9 in cochlea were observed with age and this effect was attenuated by polyphenol treatment. In addition, ATP and Bcl-2 levels in older rats were recovered after administration of polyphenols, while Bax and p53 levels protein decreased. Oral supplementation with polyphenols also reduces DNA oxidative damage of cochlear cell. Treatment with polyphenols inhibits the activation of age-related apoptotic signaling by decreasing oxidative stress inside the rat cochlea.
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Affiliation(s)
| | - Esperanza Cuadrado
- Department of biochemistry, University Hospital of Getafe, Carretera de Toledo, km 12, Getafe, 500, Madrid, Spain
| | - Juan Riestra-Ayora
- European University of Madrid, Calle del Tajo S/N, Villaviciosa de Odón, 28670, Madrid, Spain
- Department of Otolaryngology, University Hospital of Getafe, Carretera de Toledo, km 12, Getafe, 500, Madrid, Spain
| | - Ricardo Sanz-Fernández
- European University of Madrid, Calle del Tajo S/N, Villaviciosa de Odón, 28670, Madrid, Spain
- Department of Otolaryngology, University Hospital of Getafe, Carretera de Toledo, km 12, Getafe, 500, Madrid, Spain
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Watson N, Ding B, Zhu X, Frisina RD. Chronic inflammation - inflammaging - in the ageing cochlea: A novel target for future presbycusis therapy. Ageing Res Rev 2017; 40:142-148. [PMID: 29017893 DOI: 10.1016/j.arr.2017.10.002] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 10/04/2017] [Accepted: 10/06/2017] [Indexed: 12/11/2022]
Abstract
Chronic, low-grade inflammation, or inflammaging, is a crucial contributor to various age-related pathologies and natural processes in aging tissue, including the nervous system. Over the past two decades, much effort has been done to understand the mechanisms of inflammaging in disease models such as type II diabetes, cardiovascular disease, Alzheimer's disease, Parkinson's disease, and others. However, despite being the most prevalent neurodegenerative disorder, the number one communication disorder, and one of the top three chronic medical conditions of our aged population; little research has been conducted on the potential role of inflammation in age-related hearing loss (ARHL). Recently, it has been suggested that there is an inflammatory presence in the cochlea, perhaps involving diffusion processes of the blood-brain barrier as it relates to the inner ear. Recent research has found correlations between hearing loss and markers such as C-reactive protein, IL-6, and TNF-α indicating inflammatory status in human case-cohort studies. However, there have been very few reports of in vivo research investigating the role of chronic inflammation's in hearing loss in the aging cochlea. Future research directed at better understanding the mechanisms of inflammation in the cochlea as well as the natural changes acquired with aging may provide a better understanding of how this process can accelerate presbycusis. Animal model experimentation and pre-clinical studies designed to recognize and characterize cochlear inflammatory mechanisms may suggest novel treatment strategies for preventing or treating ARHL. In this review, we seek to summarize key research in chronic inflammation, discuss its implications for possible roles in ARHL, and finally suggest directions for future investigations.
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Affiliation(s)
- Nathan Watson
- Dept. Biomedical Engineering, Fitzpatrick Center (FCIEMAS), 101 Science Drive, Campus Box 90281, Duke University, Durham, NC 27708-0281, USA; Global Center for Hearing & Speech Res., 3802 Spectrum Blvd., BPB Suite 210, University of South Florida Res. Park, Tampa, FL 33612, USA; Dept. Chemical & Biomedical Engineering, 4202 E Fowler Avenue, ENB 118 University of South Florida, Tampa, FL 33620, USA
| | - Bo Ding
- Dept. Communication Sciences & Disorders, 4202 E. Fowler Avenue, PCD1017 University of South Florida, Tampa, FL 33620-8200, USA; Global Center for Hearing & Speech Res., 3802 Spectrum Blvd., BPB Suite 210, University of South Florida Res. Park, Tampa, FL 33612, USA
| | - Xiaoxia Zhu
- Dept. Communication Sciences & Disorders, 4202 E. Fowler Avenue, PCD1017 University of South Florida, Tampa, FL 33620-8200, USA; Dept. Chemical & Biomedical Engineering, 4202 E Fowler Avenue, ENB 118 University of South Florida, Tampa, FL 33620, USA
| | - Robert D Frisina
- Dept. Communication Sciences & Disorders, 4202 E. Fowler Avenue, PCD1017 University of South Florida, Tampa, FL 33620-8200, USA; Global Center for Hearing & Speech Res., 3802 Spectrum Blvd., BPB Suite 210, University of South Florida Res. Park, Tampa, FL 33612, USA; Dept. Chemical & Biomedical Engineering, 4202 E Fowler Avenue, ENB 118 University of South Florida, Tampa, FL 33620, USA.
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Pan C, Chu H, Lai Y, Liu Y, Sun Y, Du Z, Chen J, Tong T, Chen Q, Zhou L, Bing D, Tao Y. Down-regulation of the large conductance Ca(2+)-activated K(+) channel expression in C57BL/6J cochlea. Acta Otolaryngol 2016; 136:875-8. [PMID: 27093472 DOI: 10.3109/00016489.2016.1168941] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION The large conductance Ca(2+)-activated K(+ )channels (BK) expression is decreased in the cochleae of age-related hearing loss (AHL) mice. BK channel may be associated with AHL. OBJECTIVE AHL is the most common among elderly persons. BK channels act as sensors for membrane voltage and intracellular Ca(2+ )and are essential for hearing. To investigate the distribution of BK channel in the cochleae of C57BL/6J mice, and the relationship between the expression of BK channel and the etiology of AHL. METHODS BK expression was studied in the cochleae of C57BL/6J mice at various ages (4, 12, 26, 52 weeks). The expressions of BK at the protein and mRNA levels were detected by immunofluorescence technique, western blot and quantitative real time PCR. RESULTS In comparison with 4-week-old mice, BK expressions in the cochleae at 12, 26 and 52 weeks of age were significantly and gradually decreased at both the protein and the mRNA levels. The immunofluorescence technique showed the BK channel was located in the hair cells and cells of the spiral ganglion, spiral ligament and stria vascularis and its expression also decreased with aging.
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Affiliation(s)
- Chunchen Pan
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Hanqi Chu
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Yanbing Lai
- b Department of Otolaryngology-Head and Neck Surgery , the First People's Hospital of Foshan , Foshan , Guangdong , PR China
| | - Yun Liu
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Yanbo Sun
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Zhihui Du
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Jin Chen
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Ting Tong
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Qingguo Chen
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Liangqiang Zhou
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Dan Bing
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
| | - Yanling Tao
- a Department of Otolaryngology-Head and Neck Surgery , Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , PR China
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Mateo Sánchez S, Freeman SD, Delacroix L, Malgrange B. The role of post-translational modifications in hearing and deafness. Cell Mol Life Sci 2016; 73:3521-33. [PMID: 27147466 PMCID: PMC11108544 DOI: 10.1007/s00018-016-2257-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 04/21/2016] [Accepted: 04/26/2016] [Indexed: 12/20/2022]
Abstract
Post-translational modifications (PTMs) are key molecular events that modify proteins after their synthesis and modulate their ultimate functional properties by affecting their stability, localisation, interaction potential or activity. These chemical changes expand the size of the proteome adding diversity to the molecular pathways governing the biological outcome of cells. PTMs are, thus, crucial in regulating a variety of cellular processes such as apoptosis, proliferation and differentiation and have been shown to be instrumental during embryonic development. In addition, alterations in protein PTMs have been implicated in the pathogenesis of many human diseases, including deafness. In this review, we summarize the recent progress made in understanding the roles of PTMs during cochlear development, with particular emphasis on the enzymes driving protein phosphorylation, acetylation, methylation, glycosylation, ubiquitination and SUMOylation. We also discuss how these enzymes may contribute to hearing impairment and deafness.
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Affiliation(s)
- Susana Mateo Sánchez
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, Quartier Hôpital (CHU), Avenue Hippocrate 15, Tour 4, 1er étage, Bât. B36, 4000, Liège, Belgium
| | - Stephen D Freeman
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, Quartier Hôpital (CHU), Avenue Hippocrate 15, Tour 4, 1er étage, Bât. B36, 4000, Liège, Belgium
| | - Laurence Delacroix
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, Quartier Hôpital (CHU), Avenue Hippocrate 15, Tour 4, 1er étage, Bât. B36, 4000, Liège, Belgium
| | - Brigitte Malgrange
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, Quartier Hôpital (CHU), Avenue Hippocrate 15, Tour 4, 1er étage, Bât. B36, 4000, Liège, Belgium.
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22
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Pan CC, Chu HQ, Lai YB, Sun YB, Du ZH, Liu Y, Chen J, Tong T, Chen QG, Zhou LQ, Bing D, Tao YL. Downregulation of inwardly rectifying potassium channel 5.1 expression in C57BL/6J cochlear lateral wall. J Huazhong Univ Sci Technolog Med Sci 2016; 36:406-409. [PMID: 27376812 DOI: 10.1007/s11596-016-1600-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 04/20/2016] [Indexed: 10/21/2022]
Abstract
Age-related hearing loss (AHL) is one of the most common sensory disorders among elderly persons. The inwardly rectifying potassium channel 5.1 (Kir5.1) plays a vital role in regulating cochlear K(+) circulation which is necessary for normal hearing. The distribution of Kir5.1 in C57BL/6J mice cochleae, and the relationship between the expression of Kir5.1 and the etiology of AHL were investigated. Forty C57BL/6J mice were randomly divided into four groups at 4, 12, 24 and 52 weeks of age respectively. The location of Kir5.1 was detected by immunofluorescence technique. The mRNA and protein expression of Kir5.1 was evaluated in mice cochleae using real-time polymerase-chain reactions (RT-PCR) and Western blotting respectively. Kir5.1 was detected in the type II and IV fibrocytes of the spiral ligament in the cochlear lateral wall of C57BL/6J mice. The expression levels of Kir5.1 mRNA and protein in the cochleae of aging C57BL/6J mice were down-regulated. It was suggested that the age-related decreased expression of Kir5.1 in the lateral wall of C57BL/6J mice was associated with hearing loss. Our results indicated that Kir5.1 may play an important role in the pathogenesis of AHL.
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Affiliation(s)
- Chun-Chen Pan
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Han-Qi Chu
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yan-Bing Lai
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yan-Bo Sun
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Zhi-Hui Du
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yun Liu
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jin Chen
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Ting Tong
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Qing-Guo Chen
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Liang-Qiang Zhou
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Dan Bing
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yan-Ling Tao
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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23
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Dong Y, Guo CR, Ding Y, Zhang Y, Song HY, Peng YT, Zhang T, Shi JR. Effects of Erlong Zuoci decoction on the age-related hearing loss in C57BL/6J mice. J Ethnopharmacol 2016; 181:59-65. [PMID: 26826327 DOI: 10.1016/j.jep.2016.01.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 10/12/2015] [Accepted: 01/18/2016] [Indexed: 06/05/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Erlong Zuoci decoction (ELZCD), a typical traditional Chinese medicine (TCM) prescription, has long been clinically used in treatment of deafness and tinnitus with the syndrome of "kidney yin deficiency". However, there are few studies to investigate its pharmacological mechanisms. Until now, there is not report about its effects on the age-related hearing loss (ARHL). AIM OF STUDY The present study was conducted to observe the effects of ELZCD on the ARHL in C57BL/6J mice and explore the mechanisms. MATERIALS AND METHODS ELZCD was fed to C57BL/6J mice from 3 months to 6 months in ELZCD group as a dose of 6g/kg/d. And the same volume of saline was fed to mice in ARHL group. 3-months-old C57BL/6J mice were used as control group. High performance liquid chromatography (HPLC) was used for the quality control of ELZCD. Auditory brainstem response (ABR) was used to assess the hearing function of mice. The morphologic changes were observed by hematoxylin eosin (HE) staining. Apoptosis was tested by terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) method. Mitochondrial damage was detected by transmission electron microscopy (TEM). Quantitative RT-PCR (qRT-PCR) was used to observe the mRNA expression of p53 and Bak. Fluorescence immunohistochemical technique was used to test the protein expression of p53 and Bak. RESULTS The hearing threshold of ARHL group was higher than that of control group (P<0.001) and ELZCD decreased the rise of hearing threshold levels of ARHL mice (P<0.001), which suggested ELZCD inhibited the hearing loss of ARHL mice. HE staining showed that ELZCD decreased the spiral ganglion (SG) cell damage and loss in ARHL. TUNEL test showed that the apoptotic SG cells increased in ARHL group compared to control group and decreased in ELZCD group compared to ARHL group. TEM observation showed that mitochondrial damage was obvious in SG cells of ARHL group and ELZCD inhibited the mitochondrial damage. The qRT-PCR results showed that the mRNA expression of p53 and Bak in ARHL group increased compared to that of control group (P<0.05), and ELZCD reduced the elevated mRNA expression levels of p53 and Bak (P<0.01, P<0.05). In addition, ELZCD inhibited the increased proteins expression (green fluorescence) of p53 and Bak. CONCLUSION The results demonstrated that ELZCD prevented ARHL in C57BL/6J mice and p53/Bak-mediated mitochondrial apoptosis of SG cells might be involved in the mechanisms.
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Affiliation(s)
- Yang Dong
- Experimental Teaching Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Chun-Rong Guo
- Experimental Teaching Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yue Ding
- Experimental Teaching Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yong Zhang
- Experimental Teaching Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Hai-Yan Song
- Basic Medical College, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yin-Ting Peng
- Experimental Teaching Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Tong Zhang
- Experimental Teaching Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Jian-Rong Shi
- Experimental Teaching Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
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24
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Johnson KR, Longo-Guess CM, Gagnon LH. A QTL on Chr 5 modifies hearing loss associated with the fascin-2 variant of DBA/2J mice. Mamm Genome 2015; 26:338-47. [PMID: 26092689 DOI: 10.1007/s00335-015-9574-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 06/02/2015] [Indexed: 12/16/2022]
Abstract
Inbred mouse strains serve as important models for human presbycusis or age-related hearing loss. We previously mapped a locus (ahl8) contributing to the progressive hearing loss of DBA/2J (D2) mice and later showed that a missense variant of the Fscn2 gene, unique to the D2 inbred strain, was responsible for the ahl8 effect. Although ahl8 can explain much of the hearing loss difference between C57BL/6J (B6) and D2 strain mice, other loci also contribute. Here, we present results of our linkage analyses to map quantitative trait loci (QTLs) that modify the severity of hearing loss associated with the D2 strain Fscn2 (ahl8) allele. We searched for modifier loci by analyzing 31 BXD recombinant inbred (RI) lines fixed for the predisposing D2-derived Fscn2 (ahl8/ahl8) genotype and found a statistically significant linkage association of threshold means with a QTL on Chr 5, which we designated M5ahl8. The highest association (LOD 4.6) was with markers at the 84-90 Mb position of Chr 5, which could explain about 46 % of the among-RI strain variation in auditory brainstem response (ABR) threshold means. The semidominant nature of the modifying effect of M5ahl8 on the Fscn2 (ahl8/ahl8) phenotype was demonstrated by analysis of a backcross involving D2 and B6.D2-Chr11D/LusJ strain mice. The Chr 5 map position of M5ahl8 and the D2 origin of its susceptibility allele correspond to Tmc1m4, a previously reported QTL that modifies outer hair cell degeneration in Tmc1 (Bth) mutant mice, suggesting that M5ahl8 and Tmc1m4 may represent the same gene affecting maintenance of stereocilia structure and function during aging.
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MESH Headings
- Aging/genetics
- Aging/metabolism
- Aging/pathology
- Alleles
- Animals
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Chromosome Mapping
- Chromosomes, Mammalian/chemistry
- Disease Models, Animal
- Evoked Potentials, Auditory, Brain Stem
- Female
- Gene Expression
- Genetic Linkage
- Genetic Predisposition to Disease
- Genotype
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/pathology
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Phenotype
- Presbycusis/genetics
- Presbycusis/metabolism
- Presbycusis/pathology
- Quantitative Trait Loci
- Severity of Illness Index
- Species Specificity
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25
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Abstract
BACKGROUND Age-related hearing loss (ARHL) has been linked to the shift in the pro-oxidant/antioxidant ratio. Our objectives were to assess serum levels of retinol and zinc among the elderly individuals and to correlate the levels with hearing threshold. METHODS Prospective study of apparently healthy individuals aged ≥60 years of age. Participants had complete clinical history, physical examination and pure tone average conducted. Blood samples were collected for determination of serum levels of retinol and zinc. Mann-Whitney U test was used to compare retinol and zinc values. Pearson's correlation test was used to determine the relationship between hearing threshold and serum levels of retinol and zinc. RESULTS Among 126 elderly participants with mean age 67 ± 2.7 years; the mean pure tone average for air conduction was 29.3 ± 1.6 dBHL while the mean bone conduction was 36.5 ± 1.8 dBHL. The median values of serum retinol and zinc levels in the elderly participants who had hearing loss in the speech frequencies were 52 and 83.3 μg/L, respectively, while among participants with normal hearing threshold, values were 50 and 89.9 μg/L, respectively (p = 0.59 and 0.99, respectively). For the high frequencies, the median value of serum retinol and zinc levels among the elderly participants with normal hearing threshold was 70.3 and 99.9 μg/L, while among those with hearing loss, it was 46.9 and 83.2 μg/L, respectively (p = 0.000 and 0.005, respectively). CONCLUSION Serum retinol and zinc levels were significantly lower among elderly with hearing loss involving the high frequencies. This is added evidence to extant literature on the possible role of antioxidants in the development of ARHL and suggests further study on the effect of antioxidants supplementation in the control of ARHL which is presently controversial and inconclusive.
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Affiliation(s)
- Taye Jemilat Lasisi
- Departments of Physiology and Oral Pathology, College of Medicine, University of Ibadan, P. O. Box 22040, Ibadan, Nigeria,
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Xiong H, Dai M, Ou Y, Pang J, Yang H, Huang Q, Chen S, Zhang Z, Xu Y, Cai Y, Liang M, Zhang X, Lai L, Zheng Y. SIRT1 expression in the cochlea and auditory cortex of a mouse model of age-related hearing loss. Exp Gerontol 2014; 51:8-14. [PMID: 24365660 DOI: 10.1016/j.exger.2013.12.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 12/08/2013] [Accepted: 12/12/2013] [Indexed: 01/30/2023]
Abstract
SIRT1 is a highly conserved NAD(+)-dependent protein deacetylase known to have protective effects against a variety of age-related diseases. However, there is a lack of information concerning SIRT1 expression in the cochlea and auditory cortex of C57BL/6 mice, a mouse model of age-related hearing loss. Using RT-PCR and immunohistochemistry, we show that SIRT1 is abundantly expressed in the inner hair cells, strial marginal cells, strial intermediate cells, type I and type IV fibrocytes of the spiral ligament and spiral ganglion neurons. In addition, moderate SIRT1 is also detected in the outer hair cells and neurons of the auditory cortex. Associated with elevated hearing thresholds and hair cells loss during aging, there is also a significant reduction of SIRT1 expression in the cochlea and auditory cortex. The expression pattern of SIRT1 in the peripheral and central auditory system suggests that SIRT1 may play an important role in auditory function and therefore may serve as a protective molecule against age-related hearing loss.
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Affiliation(s)
- Hao Xiong
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Min Dai
- Department of Hematology, Nanfang Hospital, Southern Medical University, China
| | - Yongkang Ou
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Jiaqi Pang
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Haidi Yang
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Qiuhong Huang
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Suijun Chen
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Zhigang Zhang
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Yaodong Xu
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Yuexin Cai
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Maojin Liang
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Xueyuan Zhang
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Lan Lai
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China
| | - Yiqing Zheng
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China.
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Tadros SF, D'Souza M, Zhu X, Frisina RD. Gene expression changes for antioxidants pathways in the mouse cochlea: relations to age-related hearing deficits. PLoS One 2014; 9:e90279. [PMID: 24587312 PMCID: PMC3938674 DOI: 10.1371/journal.pone.0090279] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 01/28/2014] [Indexed: 12/17/2022] Open
Abstract
Age-related hearing loss - presbycusis - is the number one neurodegenerative disorder and top communication deficit of our aged population. Like many aging disorders of the nervous system, damage from free radicals linked to production of reactive oxygen and/or nitrogen species (ROS and RNS, respectively) may play key roles in disease progression. The efficacy of the antioxidant systems, e.g., glutathione and thioredoxin, is an important factor in pathophysiology of the aging nervous system. In this investigation, relations between the expression of antioxidant-related genes in the auditory portion of the inner ear - cochlea, and age-related hearing loss was explored for CBA/CaJ mice. Forty mice were classified into four groups according to age and degree of hearing loss. Cochlear mRNA samples were collected and cDNA generated. Using Affymetrix® GeneChip, the expressions of 56 antioxidant-related gene probes were analyzed to estimate the differences in gene expression between the four subject groups. The expression of Glutathione peroxidase 6, Gpx6; Thioredoxin reductase 1, Txnrd1; Isocitrate dehydrogenase 1, Idh1; and Heat shock protein 1, Hspb1; were significantly different, or showed large fold-change differences between subject groups. The Gpx6, Txnrd1 and Hspb1 gene expression changes were validated using qPCR. The Gpx6 gene was upregulated while the Txnrd1 gene was downregulated with age/hearing loss. The Hspb1 gene was found to be downregulated in middle-aged animals as well as those with mild presbycusis, whereas it was upregulated in those with severe presbycusis. These results facilitate development of future interventions to predict, prevent or slow down the progression of presbycusis.
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Affiliation(s)
- Sherif F. Tadros
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester, New York, United States of America
- Otolaryngology Dept., University of Rochester Medical School, Rochester, New York, United States of America
| | - Mary D'Souza
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester, New York, United States of America
- Otolaryngology Dept., University of Rochester Medical School, Rochester, New York, United States of America
| | - Xiaoxia Zhu
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester, New York, United States of America
- Otolaryngology Dept., University of Rochester Medical School, Rochester, New York, United States of America
- Depts. Chemical & Biomedical Engineering, Communication Sciences & Disorders, and Global Center for Hearing & Speech Research, University of South Florida, Tampa, Florida, United States of America
| | - Robert D. Frisina
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester, New York, United States of America
- Otolaryngology Dept., University of Rochester Medical School, Rochester, New York, United States of America
- Depts. Chemical & Biomedical Engineering, Communication Sciences & Disorders, and Global Center for Hearing & Speech Research, University of South Florida, Tampa, Florida, United States of America
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Zeng L, Yang Y, Hu Y, Sun Y, Du Z, Xie Z, Zhou T, Kong W. Age-related decrease in the mitochondrial sirtuin deacetylase Sirt3 expression associated with ROS accumulation in the auditory cortex of the mimetic aging rat model. PLoS One 2014; 9:e88019. [PMID: 24505357 PMCID: PMC3913718 DOI: 10.1371/journal.pone.0088019] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 01/03/2014] [Indexed: 12/31/2022] Open
Abstract
Age-related dysfunction of the central auditory system, also known as central presbycusis, can affect speech perception and sound localization. Understanding the pathogenesis of central presbycusis will help to develop novel approaches to prevent or treat this disease. In this study, the mechanisms of central presbycusis were investigated using a mimetic aging rat model induced by chronic injection of D-galactose (D-Gal). We showed that malondialdehyde (MDA) levels were increased and manganese superoxide dismutase (SOD2) activity was reduced in the auditory cortex in natural aging and D-Gal-induced mimetic aging rats. Furthermore, mitochondrial DNA (mtDNA) 4834 bp deletion, abnormal ultrastructure and cell apoptosis in the auditory cortex were also found in natural aging and D-Gal mimetic aging rats. Sirt3, a mitochondrial NAD+-dependent deacetylase, has been shown to play a crucial role in controlling cellular reactive oxygen species (ROS) homeostasis. However, the role of Sirt3 in the pathogenesis of age-related central auditory cortex deterioration is still unclear. Here, we showed that decreased Sirt3 expression might be associated with increased SOD2 acetylation, which negatively regulates SOD2 activity. Oxidative stress accumulation was likely the result of low SOD2 activity and a decline in ROS clearance. Our findings indicate that Sirt3 might play an essential role, via the mediation of SOD2, in central presbycusis and that manipulation of Sirt3 expression might provide a new approach to combat aging and oxidative stress-related diseases.
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Affiliation(s)
- Lingling Zeng
- Department of Otorhinolaryngology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei province, P. R. China
| | - Yang Yang
- Department of Otorhinolaryngology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei province, P. R. China
| | - Yujuan Hu
- Department of Otorhinolaryngology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei province, P. R. China
| | - Yu Sun
- Department of Otorhinolaryngology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei province, P. R. China
| | - Zhengde Du
- Department of Otorhinolaryngology, Nanshan Affiliated Hospital of Guangdong Medical College, Shenzhen, China
| | - Zhen Xie
- Department of Otorhinolaryngology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei province, P. R. China
| | - Tao Zhou
- Department of Otorhinolaryngology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei province, P. R. China
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei province, P. R. China
- * E-mail:
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Saremi A, Stenfelt S. Effect of metabolic presbyacusis on cochlear responses: a simulation approach using a physiologically-based model. J Acoust Soc Am 2013; 134:2833-2851. [PMID: 24116421 DOI: 10.1121/1.4820788] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In the presented model, electrical, acoustical, and mechanical elements of the cochlea are explicitly integrated into a signal transmission line where these elements convey physiological interpretations of the human cochlear structures. As a result, this physiologically-motivated model enables simulation of specific cochlear lesions such as presbyacusis. The hypothesis is that high-frequency hearing loss in older adults may be due to metabolic presbyacusis whereby age-related cellular/chemical degenerations in the lateral wall of the cochlea cause a reduction in the endocochlear potential. The simulations quantitatively confirm this hypothesis and emphasize that even if the outer and inner hair cells are totally active and intact, metabolic presbyacusis alone can significantly deteriorate the cochlear functionality. Specifically, in the model, as the endocochlear potential decreases, the transduction mechanism produces less receptor current such that there is a reduction in the battery of the somatic motor. This leads to a drastic decrease in cochlear amplification and frequency sensitivity, as well as changes in position-frequency map (tuning pattern) of the cochlea. In addition, the simulations show that the age-related reduction of the endocochlear potential significantly inhibits the firing rate of the auditory nerve which might contribute to the decline of temporal resolution in the aging auditory system.
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MESH Headings
- Action Potentials
- Age Factors
- Aging/metabolism
- Animals
- Cochlea/metabolism
- Cochlea/pathology
- Cochlea/physiopathology
- Cochlear Nerve/metabolism
- Cochlear Nerve/physiopathology
- Computer Simulation
- Evoked Potentials
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/pathology
- Hearing
- Humans
- Linear Models
- Mechanotransduction, Cellular
- Models, Biological
- Nonlinear Dynamics
- Presbycusis/metabolism
- Presbycusis/pathology
- Presbycusis/physiopathology
- Pressure
- Time Factors
- Vibration
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Affiliation(s)
- Amin Saremi
- Department of Clinical and Experimental Medicine, Division of Technical Audiology, Linköping University, 581 85 Linköping, Sweden
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Yamasoba T, Lin FR, Someya S, Kashio A, Sakamoto T, Kondo K. Current concepts in age-related hearing loss: epidemiology and mechanistic pathways. Hear Res 2013; 303:30-8. [PMID: 23422312 PMCID: PMC3723756 DOI: 10.1016/j.heares.2013.01.021] [Citation(s) in RCA: 344] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 12/20/2012] [Accepted: 01/29/2013] [Indexed: 01/10/2023]
Abstract
Age-related hearing loss (AHL), also known as presbycusis, is a universal feature of mammalian aging and is characterized by a decline of auditory function, such as increased hearing thresholds and poor frequency resolution. The primary pathology of AHL includes the hair cells, stria vascularis, and afferent spiral ganglion neurons as well as the central auditory pathways. A growing body of evidence in animal studies has suggested that cumulative effect of oxidative stress could induce damage to macromolecules such as mitochondrial DNA (mtDNA) and that the resulting accumulation of mtDNA mutations/deletions and decline of mitochondrial function play an important role in inducing apoptosis of the cochlear cells, thereby the development of AHL. Epidemiological studies have demonstrated four categories of risk factors of AHL in humans: cochlear aging, environment such as noise exposure, genetic predisposition, and health co-morbidities such as cigarette smoking and atherosclerosis. Genetic investigation has identified several putative associating genes, including those related to antioxidant defense and atherosclerosis. Exposure to noise is known to induce excess generation of reactive oxygen species (ROS) in the cochlea, and cumulative oxidative stress can be enhanced by relatively hypoxic situations resulting from the impaired homeostasis of cochlear blood supply due to atherosclerosis, which could be accelerated by genetic and co-morbidity factors. Antioxidant defense system may also be influenced by genetic backgrounds. These may explain the large variations of the onset and extent of AHL among elderly subjects. This article is part of a Special Issue entitled "Annual Reviews 2013".
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Affiliation(s)
- Tatsuya Yamasoba
- Department of Otolaryngology and Head and Neck Surgery, University of Tokyo, Tokyo, Japan.
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Chen XM, Dou XQ, Liang YH, Zhang LW, Luo BQ, Deng YH. [(1)H-MRS study of auditory cortex in patients with presbycusis]. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2012; 47:852-855. [PMID: 23302169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To study the metabolic changes of auditory cortex in patients with presbycusis by using proton magnetic resonance spectroscopy ((1)H-MRS). METHODS Ten normal hearing volunteers (youth group), 10 normal hearing of elderly (aged group) and 8 patients with presbycusis (presbycusis group) were checked with proton magnetic resonance spectroscopy. N-acetylaspartic acid (NAA), creatine (Cr), choline (Cho), γ-aminobutyric acid (GABA), glutamic acid (Glu) compound were measured. The differences between the groups were semi-quantitatively analyzed. RESULTS When compared with youth group, reduced NAA/Cr, increased Cho/Cr were found in the aged group and presbycusis group (P < 0.05). GABA/Cr ratio and Glu/Cr ratio were significant difference between presbycusis group and youth group (P < 0.05). There were no significant difference in the GABA/Cr and Glu/Cr ratios in the bilateral auditory cortex between the youth group and the aged group (P > 0.05). When compared with aged group, the metabolic changes of auditory cortex in patients with presbycusis were remarkable (P < 0.05). CONCLUSIONS (1)H-MRS is a noninvasive technique that can provide useful information concerning the metabolic changes of auditory cortex in human. In comparison to the aged group and the youth group, the changes of NAA, GABA, Cho and Glu is found in auditory cortex in patients with presbycusis.
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Affiliation(s)
- Xian-ming Chen
- Department of Otorhinolaryngology Head and Neck Surgery, Fuzhou General Hospital of People's Liberation Army, Fuzhou , China.
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Kane KL, Longo-Guess CM, Gagnon LH, Ding D, Salvi RJ, Johnson KR. Genetic background effects on age-related hearing loss associated with Cdh23 variants in mice. Hear Res 2011; 283:80-8. [PMID: 22138310 DOI: 10.1016/j.heares.2011.11.007] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 11/07/2011] [Accepted: 11/08/2011] [Indexed: 12/18/2022]
Abstract
Inbred strain variants of the Cdh23 gene have been shown to influence the onset and progression of age-related hearing loss (AHL) in mice. In linkage backcrosses, the recessive Cdh23 allele (ahl) of the C57BL/6J strain, when homozygous, confers increased susceptibility to AHL, while the dominant allele (Ahl+) of the CBA/CaJ strain confers resistance. To determine the isolated effects of these alleles on different strain backgrounds, we produced the reciprocal congenic strains B6.CBACa-Cdh23(Ahl)(+) and CBACa.B6-Cdh23(ahl) and tested 15-30 mice from each for hearing loss progression. ABR thresholds for 8 kHz, 16 kHz, and 32 kHz pure-tone stimuli were measured at 3, 6, 9, 12, 15 and 18 months of age and compared with age-matched mice of the C57BL/6J and CBA/CaJ parental strains. Mice of the C57BL/6N strain, which is the source of embryonic stem cells for the large International Knockout Mouse Consortium, were also tested for comparisons with C57BL/6J mice. Mice of the C57BL/6J and C57BL/6N strains exhibited identical hearing loss profiles: their 32 kHz ABR thresholds were significantly higher than those of CBA/CaJ and congenic strain mice by 6 months of age, and their 16 kHz thresholds were significantly higher by 12 months. Thresholds of the CBA/CaJ, the B6.CBACa-Cdh23(Ahl)(+), and the CBACa.B6-Cdh23(ahl) strain mice differed little from one another and only slightly increased throughout the 18-month test period. Hearing loss, which corresponded well with cochlear hair cell loss, was most profound in the C57BL/6J and C57BL/6NJ strains. These results indicate that the CBA/CaJ-derived Cdh23(Ahl)(+) allele dramatically lessens hearing loss and hair cell death in an otherwise C57BL/6J genetic background, but that the C57BL/6J-derived Cdh23(ahl) allele has little effect on hearing loss in an otherwise CBA/CaJ background. We conclude that although Cdh23(ahl) homozygosity is necessary, it is not by itself sufficient to account for the accelerated hearing loss of C57BL/6J mice.
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MESH Headings
- Acoustic Stimulation
- Age Factors
- Aging
- Animals
- Audiometry, Pure-Tone
- Auditory Threshold
- Cadherins/genetics
- Cadherins/metabolism
- Cochlea/metabolism
- Cochlea/pathology
- Cochlea/physiopathology
- Disease Models, Animal
- Evoked Potentials, Auditory, Brain Stem
- Female
- Genetic Predisposition to Disease
- Hair Cells, Auditory/metabolism
- Hair Cells, Auditory/pathology
- Male
- Mice
- Mice, Congenic
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Transgenic
- Phenotype
- Polymorphism, Single Nucleotide
- Presbycusis/genetics
- Presbycusis/metabolism
- Presbycusis/pathology
- Presbycusis/physiopathology
- Species Specificity
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Affiliation(s)
- Kelly L Kane
- The Jackson Laboratory, Bar Harbor, 600 Main Street, ME 04609, USA
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Wang Y, Chu HQ, Zhou LQ, Chen J, Li ZY, Liu Y, Zhang P, Huang XW, Cui YH. [Expression of PDCD5 and caspase 3 in the cochlea of different age of C57BL/6J mice]. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2011; 46:747-751. [PMID: 22177044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVE To investigate the age related changes of the expression of programmed cell death 5 (PDCD5) and caspase 3 in the cochlea of the different age of C57BL/6J mice. The relationship of PDCD5 and caspase 3 and the possible roles in the pathogenesis of presbycusis were also discussed. METHODS C57 mice of 3, 6, 9 and 12 months old were selected and divided into 4 groups, with 15 mice in each group. Auditory function of C57BL/6J mice was measured by auditory brainstem response (ABR) respectively. The changes of PDCD5 and Caspase 3 protein in the cochlea were detected by immunohistochemistry and Western blotting, the changes of PDCD5 mRNA and caspase 3 mRNA were detected using RT-PCR. RESULTS With the increase of age, the mean value for ABR thresholds in response to click, 4 kHz and 8 kHz sound stimulus of C57 mice gradually increased, the expression of PDCD5 and caspase 3 were increased also. At 3 months and 6 months of age in the cochlea of C57, all sorts of expression of PDCD5 and caspase 3 and the expression were enhanced with age. There was an evident expression at 9 months age, but the highest expression was detected at 12 months age. The PDCD5 and Caspase 3 expression were statistically different in each group (P < 0.05). The changes of PDCD5 and caspase 3 mRNA expression were in accordance with that of PDCD5 and Caspase 3 protein expression by the real-time PCR. CONCLUSIONS The expression levels of PDCD5 and caspase 3 in the cochlea of C57 mice increase with age, the results suggested that the expression of PDCD5 and caspase 3 might play an important role in the pathogenic mechanism of presbycusis.
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Affiliation(s)
- Yan Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Lei D, Gao X, Perez P, Ohlemiller KK, Chen CC, Campbell KP, Hood AY, Bao J. Anti-epileptic drugs delay age-related loss of spiral ganglion neurons via T-type calcium channel. Hear Res 2011; 278:106-12. [PMID: 21640179 PMCID: PMC3152691 DOI: 10.1016/j.heares.2011.05.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 04/29/2011] [Accepted: 05/11/2011] [Indexed: 12/26/2022]
Abstract
Loss of spiral ganglion neurons is a major cause of age-related hearing loss (presbycusis). Despite being the third most prevalent condition afflicting elderly persons, there are no known medications to prevent presbycusis. Because calcium signaling has long been implicated in age-related neuronal death, we investigated T-type calcium channels. This family is comprised of three members (Ca(v)3.1, Ca(v)3.2, and Ca(v)3.3), based on their respective main pore-forming alpha subunits: α1G, α1H, and α1I. In the present study, we report a significant delay of age-related loss of cochlear function and preservation of spiral ganglion neurons in α1H null and heterozygous mice, clearly demonstrating an important role for Ca(v)3.2 in age-related neuronal loss. Furthermore, we show that anticonvulsant drugs from a family of T-type calcium channel blockers can significantly preserve spiral ganglion neurons during aging. To our knowledge, this is the first report of drugs capable of diminishing age-related loss of spiral ganglion neurons.
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MESH Headings
- Aging/drug effects
- Aging/metabolism
- Aging/pathology
- Animals
- Anticonvulsants/pharmacology
- Base Sequence
- Calcium Channel Blockers/pharmacology
- Calcium Channels, T-Type/deficiency
- Calcium Channels, T-Type/genetics
- Calcium Channels, T-Type/metabolism
- Evoked Potentials, Auditory, Brain Stem/drug effects
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Outer/pathology
- Mice
- Mice, Congenic
- Mice, Knockout
- Neurons/drug effects
- Neurons/metabolism
- Neurons/pathology
- Presbycusis/metabolism
- Presbycusis/pathology
- Presbycusis/prevention & control
- RNA/genetics
- RNA/metabolism
- Spiral Ganglion/drug effects
- Spiral Ganglion/innervation
- Spiral Ganglion/metabolism
- Spiral Ganglion/pathology
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Affiliation(s)
- Debin Lei
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- Center for Aging, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Xia Gao
- Department of Otolaryngology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China 210008
| | - Philip Perez
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- Center for Aging, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Kevin K Ohlemiller
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Chien-Chang Chen
- Howard Hughes Medical Institute, University of Iowa, Iowa City, Iowa, 60153, USA
| | - Kevin P. Campbell
- Howard Hughes Medical Institute, University of Iowa, Iowa City, Iowa, 60153, USA
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, 60153, USA
- Department of Neurology, University of Iowa, Iowa City, Iowa, 60153, USA
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, 60153, USA
| | - Aizhen Yang Hood
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- Center for Aging, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Jianxin Bao
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- Center for Aging, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- The Division of Biology & Biomedical Science and Neuroscience Program, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
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Lubka-Pathak M, Shah AA, Gallozzi M, Müller M, Zimmermann U, Löwenheim H, Pfister M, Knipper M, Blin N, Schimmang T. Altered expression of securin (Pttg1) and serpina3n in the auditory system of hearing-impaired Tff3-deficient mice. Cell Mol Life Sci 2011; 68:2739-49. [PMID: 21076990 PMCID: PMC11114927 DOI: 10.1007/s00018-010-0586-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 10/22/2010] [Accepted: 10/26/2010] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Tff3 peptide exerts important functions in cytoprotection and restitution of the gastrointestinal (GI) tract epithelia. Moreover, its presence in the rodent inner ear and involvement in the hearing process was demonstrated recently. However, its role in the auditory system still remains elusive. Our previous results showed a deterioration of hearing with age in Tff3-deficient animals. RESULTS Present detailed analysis of auditory brain stem response (ABR) measurements and immunohistochemical study of selected functional proteins indicated a normal function and phenotype of the cochlea in Tff3 mutants. However, a microarray-based screening of tissue derived from the auditory central nervous system revealed an alteration of securin (Pttg1) and serpina3n expression between wild-type and Tff3 knock-out animals. This was confirmed by qRT-PCR, immunostaining and western blots. CONCLUSIONS We found highly down-regulated Pttg1 and up-regulated serpina3n expression as a consequence of genetically deleting Tff3 in mice, indicating a potential role of these factors during the development of presbyacusis.
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Affiliation(s)
- M. Lubka-Pathak
- Division of Molecular Genetics, Institute of Human Genetics, University of Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany
| | - A. A. Shah
- Division of Molecular Genetics, Institute of Human Genetics, University of Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany
| | - M. Gallozzi
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, C/Sanz y Forés 3, 47003 Valladolid, Spain
| | - M. Müller
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - U. Zimmermann
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - H. Löwenheim
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - M. Pfister
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - M. Knipper
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - N. Blin
- Division of Molecular Genetics, Institute of Human Genetics, University of Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany
| | - T. Schimmang
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, C/Sanz y Forés 3, 47003 Valladolid, Spain
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36
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Abstract
Spiral ganglion neurons (SGNs) are the relay station for auditory information between hair cells and central nervous system. Age-related decline of auditory function due to SGN loss can not be ameliorated by hearing aids or cochlear implants. Recent findings clearly indicate that survival of SGNs during aging depends on genetic and environmental interactions, which can be demonstrated at the systemic, tissue, cellular, and molecular levels. At the systemic level, both insulin/insulin-like growth factor-1 and lipophilic/steroid hormone pathways influence SGN survival during aging. At the level of organ of the Corti, it is difficult to determine whether age-related SGN loss is primary or secondary degeneration. However, a late stage of SGN degeneration may be independent of age-related loss of hair cells. At the cellular and molecular level, several pathways, particularly free radical and calcium signaling pathways, can influence age-related SGN loss, and further studies should determine how these pathways contribute to SGN loss, such as whether they directly or indirectly act on SGNs. With the advancement of recent genetic and pharmacologic tools, we should not only understand how SGNs die during aging, but also find ways to delay this loss.
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Affiliation(s)
- Jianxin Bao
- Fay and Carl Simmons Center for the Biology of Hearing and Deafness, Department of Otolaryngology, Washington University Medical School, 660 S. Euclid, St. Louis, MO 63110, USA.
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Friedman RA, Van Laer L, Huentelman MJ, Sheth SS, Van Eyken E, Corneveaux JJ, Tembe WD, Halperin RF, Thorburn AQ, Thys S, Bonneux S, Fransen E, Huyghe J, Pyykkö I, Cremers CWRJ, Kremer H, Dhooge I, Stephens D, Orzan E, Pfister M, Bille M, Parving A, Sorri M, Van de Heyning PH, Makmura L, Ohmen JD, Linthicum FH, Fayad JN, Pearson JV, Craig DW, Stephan DA, Van Camp G. GRM7 variants confer susceptibility to age-related hearing impairment. Hum Mol Genet 2009; 18:785-96. [PMID: 19047183 PMCID: PMC2638831 DOI: 10.1093/hmg/ddn402] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 11/20/2008] [Indexed: 01/22/2023] Open
Abstract
Age-related hearing impairment (ARHI), or presbycusis, is the most prevalent sensory impairment in the elderly. ARHI is a complex disease caused by an interaction between environmental and genetic factors. Here we describe the results of the first whole genome association study for ARHI. The study was performed using 846 cases and 846 controls selected from 3434 individuals collected by eight centers in six European countries. DNA pools for cases and controls were allelotyped on the Affymetrix 500K GeneChip for each center separately. The 252 top-ranked single nucleotide polymorphisms (SNPs) identified in a non-Finnish European sample group (1332 samples) and the 177 top-ranked SNPs from a Finnish sample group (360 samples) were confirmed using individual genotyping. Subsequently, the 23 most interesting SNPs were individually genotyped in an independent European replication group (138 samples). This resulted in the identification of a highly significant and replicated SNP located in GRM7, the gene encoding metabotropic glutamate receptor type 7. Also in the Finnish sample group, two GRM7 SNPs were significant, albeit in a different region of the gene. As the Finnish are genetically distinct from the rest of the European population, this may be due to allelic heterogeneity. We performed histochemical studies in human and mouse and showed that mGluR7 is expressed in hair cells and in spiral ganglion cells of the inner ear. Together these data indicate that common alleles of GRM7 contribute to an individual's risk of developing ARHI, possibly through a mechanism of altered susceptibility to glutamate excitotoxicity.
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Affiliation(s)
- Rick A Friedman
- House Ear Institute, Gonda Research Center for Cell and Molecular Biology, Los Angeles, CA, USA.
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38
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Abstract
The BALB/c mouse is an established model for the early development of sensorineural hearing loss, and is homozygous for the Ahl allele (age-related hearing loss). The present study was designed to determine how auditory peripheral pathology influences calcium-binding protein immunoreactivity in the cochlear nucleus in aged BALB/c mice. To address this issue the loss of hair cells, spiral ganglion neurons (SGN), and neurons in the dorsal (DCN) and posteroventral (PVCN) cochlear nucleus of BALB/c mice at 1 and 24 months of age were quantified using CAST stereological methods. These values were then compared to the percent increase in immunopositive calcium-binding proteins in the cochlear nucleus. By 24 months of age there was a near complete loss of all outer hair cells (OHC). The inner hair cell (IHC) loss was near complete in the more apical and basal regions, while in the mid-regions approximately 50% were missing. The SGN in the apical and middle turns show a 20% loss (re: 1 month) and the basal turn up to 80% loss. A statistically significant decrease in the density of DCN and PVCN neurons (25%) was found at 24 months of age compared to the one month old animals. The percentage of parvalbumin and calretinin positive neurons in the DCN and the PVCN in relation to the density of Nissl stained neurons showed significant increases at 24 months compared to the 1 month old animals. We also determine the relationship between peripheral pathology and the percent increase in calcium-binding protein immunoreactivity. In the DCN, the percent increase of calretinin and parvalbumin was correlated to the loss of SGN, IHCs and OHCs. In the PVCN, parvalbumin was correlated to SGN, IHC, and OHC loss. The percent increase in calbindin immunoreactivity was not correlated to any peripheral pathology. The data here suggest a percent increase in calcium-binding protein immunoreactivity in the cochlea nucleus in the 24 month old mice may reflect an endogenous protective strategy that is designed to counteract calcium overload that is prominent during aging and degeneration. These results will be valuable for understanding the relationship among the peripheral and central auditory system in a model demonstrating a rapidly progressive presbyacusis.
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Affiliation(s)
- Esma Idrizbegovic
- Department of Audiology Karolinska University Hospital, Stockholm, Sweden
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Yamasoba T, Someya S, Yamada C, Weindruch R, Prolla TA, Tanokura M. Role of mitochondrial dysfunction and mitochondrial DNA mutations in age-related hearing loss. Hear Res 2007; 226:185-93. [PMID: 16870370 DOI: 10.1016/j.heares.2006.06.004] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Revised: 05/29/2006] [Accepted: 06/12/2006] [Indexed: 10/24/2022]
Abstract
Mitochondrial DNA (mtDNA) mutations/deletions are considered to be associated with the development of age-related hearing loss (AHL). We assessed the role of accumulation of mtDNA mutations in the development of AHL using Polg(D257A) knock-in mouse, which exhibited increased spontaneous mtDNA mutation rates during aging and showed accelerated aging primarily due to increased apoptosis. They exhibited moderate hearing loss and degeneration of the hair cells, spiral ganglion cells and stria vascularis by 9 month of age, while wild-type animals did not. We next examined if mitochondrial damage induced by systemic application of germanium dioxide caused progressive hearing loss and cochlear damage. Guinea pigs and mice given germanium dioxide exhibited degeneration of the muscles and kidney and developed hearing loss due to degeneration of cochlear tissues, including the stria vascularis. Calorie restriction, which causes a metabolic shift toward increased energy metabolism in some organs, has been shown to attenuate AHL and age-related cochlear degeneration and to lower quantity of mtDNA deletions in the cochlea of mammals. Together these findings indicate that decreased energy metabolism due to accumulation of mtDNA mutations/deletions and decline of respiratory chain function play an important role in the manifestation of AHL.
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Affiliation(s)
- Tatsuya Yamasoba
- Department of Otolaryngology and Head and Neck Surgery, University of Tokyo, Hongo 7-3-1, Tokyo 113-8665, Japan.
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40
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Abstract
Age-related cochlear structural changes include the degeneration of sensory, neural cells and the stria vascularis. The hypothesis that cellular degeneration results from exposure to oxidative products of respiration was tested by supplementing aged dogs with a diet high in antioxidants and mitochondrial metabolites and by genetically modifying the expression level of the antioxidant, manganese superoxide dismutase (SOD2) in mice. Aged dogs received either a high antioxidant diet or a normal, control diet for the last 3 years of their life. Cellular measures were compared among the two aged groups (10-15 years) and young dogs. Both aged groups had cellular degeneration relative to young dogs, but the animals fed the antioxidant diet showed less degeneration at the base and apex than the control-diet group. Transgenic mice, heterozygous null for SOD2, produce only half as much enzyme as a normal mouse. These mice showed no increase in the amount of hearing loss relative to the background strain. A diet containing antioxidants reduced the magnitude of cochlear degeneration. Genetic reduction of one antioxidant, however, did not increase the magnitude of hearing loss in aging mice. A reduction in one enzyme seems to be compensated while the addition of a complex of factors is effective.
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Affiliation(s)
- Tima Le
- University of California, San Diego, Head and Neck Surgery-Otolaryngology, 9500 Gilman Dr., La Jolla, CA 92093-0666, USA
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41
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Tadros SF, D’Souza M, Zettel ML, Zhu X, Frisina RD. Glutamate-related gene expression changes with age in the mouse auditory midbrain. Brain Res 2006; 1127:1-9. [PMID: 17113045 PMCID: PMC2423939 DOI: 10.1016/j.brainres.2006.09.081] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Revised: 09/18/2006] [Accepted: 09/25/2006] [Indexed: 01/01/2023]
Abstract
Glutamate is the main excitatory neurotransmitter in both the peripheral and central auditory systems. Changes of glutamate and glutamate-related genes with age may be an important factor in the pathogenesis of age-related hearing loss-presbycusis. In this study, changes in glutamate-related mRNA gene expression in the CBA mouse inferior colliculus with age and hearing loss were examined and correlations were sought between these changes and functional hearing measures, such as the auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs). Gene expression of 68 glutamate-related genes was investigated using both genechip microarray and real-time PCR (qPCR) molecular techniques for four different age/hearing loss CBA mouse subject groups. Two genes showed consistent differences between groups for both the genechip and qPCR. Pyrroline-5-carboxylate synthetase enzyme (Pycs) showed down-regulation with age and a high-affinity glutamate transporter (Slc1a3) showed up-regulation with age and hearing loss. Since Pycs plays a role in converting glutamate to proline, its deficiency in old age may lead to both glutamate increases and proline deficiencies in the auditory midbrain, playing a role in the subsequent inducement of glutamate toxicity and loss of proline neuroprotective effects. The up-regulation of Slc1a3 gene expression may reflect a cellular compensatory mechanism to protect against age-related glutamate or calcium excitoxicity.
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Affiliation(s)
- Sherif F. Tadros
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
| | - Mary D’Souza
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
| | - Martha L. Zettel
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
| | - XiaoXia Zhu
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
| | - Robert D. Frisina
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
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42
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Someya S, Yamasoba T, Weindruch R, Prolla TA, Tanokura M. Caloric restriction suppresses apoptotic cell death in the mammalian cochlea and leads to prevention of presbycusis. Neurobiol Aging 2006; 28:1613-22. [PMID: 16890326 DOI: 10.1016/j.neurobiolaging.2006.06.024] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Revised: 06/20/2006] [Accepted: 06/22/2006] [Indexed: 12/20/2022]
Abstract
Presbycusis is characterized by an age-related progressive decline of auditory function, and arises mainly from the degeneration of hair cells or spiral ganglion (SG) cells in the cochlea. Here we show that caloric restriction suppresses apoptotic cell death in the mouse cochlea and prevents late onset of presbycusis. Calorie restricted (CR) mice, which maintained body weight at the same level as that of young control (YC) mice, retained normal hearing and showed no cochlear degeneration. CR mice also showed a significant reduction in the number of TUNEL-positive cells and cleaved caspase-3-positive cells relative to middle-age control (MC) mice. Microarray analysis revealed that CR down-regulated the expression of 24 apoptotic genes, including Bak and Bim. Taken together, our findings suggest that loss of critical cells through apoptosis is an important mechanism of presbycusis in mammals, and that CR can retard this process by suppressing apoptosis in the inner ear tissue.
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Affiliation(s)
- Shinichi Someya
- Department of Genetics, University of Wisconsin, Madison, WI 53706, USA
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43
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Rüttiger L, Panford-Walsh R, Schimmang T, Tan J, Zimmermann U, Rohbock K, Köpschall I, Limberger A, Müller M, Fraenzer JT, Cimerman J, Knipper M. BDNF mRNA expression and protein localization are changed in age-related hearing loss. Neurobiol Aging 2006; 28:586-601. [PMID: 16580094 DOI: 10.1016/j.neurobiolaging.2006.02.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 01/26/2006] [Accepted: 02/09/2006] [Indexed: 11/16/2022]
Abstract
A decline in neuronal plasticity during the adult life span has been proposed to be associated with a reduced level of the effectors of plasticity responses (e.g., BDNF). Alteration of plasticity is also correlated with age-related hearing loss (presbycusis), but to date no detailed studies of BDNF expression have been performed in the young or aging mature cochlea. We have used rat and gerbil animal models for presbycusis, which displayed hearing loss in the final third of the animals' natural life span. We demonstrate for the first time a co-localization of BDNF protein, transcripts III and IV in cochlear neurons with a declining distribution towards low-frequency processing cochlear turns. BDNF protein was also found within the neuronal projections of the cochlea. A significant reduction of BDNF transcripts in high-frequency processing cochlear neurons was observed during aging, though this did not coincide with a major reduction of BDNF protein. In contrast, BDNF protein in peripheral and central projections was drastically reduced. Our results suggest that reduced BDNF protein levels in auditory nerves over age may be a crucial factor in the altered brainstem plasticity observed during presbycusis.
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Affiliation(s)
- Lukas Rüttiger
- Molecular Neurobiology, Tübingen Hearing Research Center, Department of Otorhinolaryngology, University of Tübingen, Tübingen, Germany
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Bao J, Lei D, Du Y, Ohlemiller KK, Beaudet AL, Role LW. Requirement of nicotinic acetylcholine receptor subunit beta2 in the maintenance of spiral ganglion neurons during aging. J Neurosci 2006; 25:3041-5. [PMID: 15788760 PMCID: PMC2280031 DOI: 10.1523/jneurosci.5277-04.2005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Age-related hearing loss (presbycusis) is a major health concern for the elderly. Loss of spiral ganglion neurons (SGNs), the primary sensory relay of the auditory system, is associated consistently with presbycusis. The causative molecular events responsible for age-related loss of SGNs are unknown. Recent reports directly link age-related neuronal loss in cerebral cortex with the loss of high-affinity nicotine acetylcholine receptors (nAChRs). In cochlea, cholinergic synapses are made by olivocochlear efferent fibers on the outer hair cells that express alpha9 nAChR subunits and on the peripheral projections of SGNs that express alpha2, alpha4-7, and beta2-3 nAChR subunits. A significantly decreased expression of the beta2 nAChR subunit in SGNs was found specifically in mice susceptible to presbycusis. Furthermore, mice lacking the beta2 nAChR subunit (beta2-/-), but not mice lacking the alpha5 nAChR subunit (alpha5-/-), have dramatic hearing loss and significant reduction in the number of SGNs. Our findings clearly established a requirement for beta2 nAChR subunit in the maintenance of SGNs during aging.
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MESH Headings
- Acoustic Stimulation/methods
- Age Factors
- Aging/metabolism
- Animals
- Blotting, Northern/methods
- Blotting, Western/methods
- Cadherins/genetics
- Disease Models, Animal
- Dose-Response Relationship, Radiation
- Evoked Potentials, Auditory, Brain Stem/genetics
- Gene Expression Regulation/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Mutant Strains
- Neurons/metabolism
- Presbycusis/genetics
- Presbycusis/metabolism
- Presbycusis/physiopathology
- Protein Subunits/deficiency
- Protein Subunits/genetics
- Protein Subunits/metabolism
- RNA, Messenger/metabolism
- Receptors, Nicotinic/deficiency
- Receptors, Nicotinic/genetics
- Receptors, Nicotinic/metabolism
- Receptors, Nicotinic/physiology
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Spiral Ganglion/cytology
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Affiliation(s)
- Jianxin Bao
- Department of Otolaryngology, Center for Aging, Washington University, St. Louis, Missouri 63110, USA.
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45
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Riva C, Longuet M, Lucciano M, Magnan J, Lavieille JP. [Implication of mitochondrial apoptosis in neural degeneration of cochlea in a murine model for presbycusis]. Rev Laryngol Otol Rhinol (Bord) 2005; 126:67-74. [PMID: 16180344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
HYPOTHESIS Pathologies of senescence, in particular those of neurosensory organs represent an important health problem. The improvement of the life expectation entails the fast increase of the frequency of the presbyacusis in the population. The biological and molecular causes of this degenerative pathology of the inner ear are linked to the disappearance of the sensory cells (inner and outer hair cells) and are associated to nervous damages of the spiral ganglion in the cochlea. We were interested in mechanisms causing the cochlear degeneration in a model of mouse CD 1 presenting prematurely auditive losses. MATERIALS AND METHODS We tried to correlate the evolution of the hearing and the appearance of apoptotic phenomena by marking with specific antibody, activated anti-caspase-3, in the cochlea during time. We studied the role and the involvement of proteins controlling the apoptosis as the P53 protein and from an energy point of view at the level of the mitochondria such as proteins of the Bcl-2 family and the cytochrome c in the various structures of the cochlea. RESULTS After implantation of electrodes for auditory nerve acoustic thresholds measurements, the audition of mice CD 1 presented a characteristic profile of hearing losses which begins in the high frequencies from the age of 1 month and which quickly evolves towards the low frequencies. The observation (between the 1st and 3rd month of age) of spiral ganglion cells revealed an unchanged number of cellular bodies of type 1 neurons, on the other hand a characteristic morphology of apoptosis of glial cells with the formation of apoptotic body was noted. Indeed, glial cells expressed activated caspase-3. Furthermore, this phenomenon seems to be under the control of the pro-apoptotic protein Bax by its overexpression and a increased release of the cytochrome c. This phenomenon was followed at 3 and 6 months by the disappearance of the outer hair cells by 9 and 48% respectively. CONCLUSION The apparition of the deafness in the murin model CD 1 allowed us to demonstrate that the degeneration of cochlear structure begins at the level of glial cells of the spiral ganglion from 3 months, followed thereafter by the deterioration of the nervous conduction between the spiral ganglion and the sensory cells. As a consequence, because of the impoverishment in nervous signals, the outer hair cells would begin to disappear during the 6th month. In conclusion, the understanding of the sequence and the cause of these mechanisms responsible for the neural degeneration and the loss of hearing could eventually, allow us to optimize the various treatments of the presbyacusis.
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Affiliation(s)
- C Riva
- Laboratoire d'Otologie Neuro-Otologie et Microendoscopie Université de la Méditerranée Aix-Marseille II, IFR Jean Roche, Faculté de Médecine Nord, Boulevard Pierre Dramard, F-13916 Marseille cedex 20, France.
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46
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Abstract
Reactive oxygen metabolites are products of oxidative metabolism that are continuously generated in vivo, and are known to produce serious cellular, tissue and genomic damage. l-carnitine is an endogenous amine that has been shown to have an effect on the synthesis of reactive oxygen metabolites. Twenty Wistar rats, 24 months of age, were randomly assigned to two groups as control and l-carnitine treatment groups. One millilitre of distilled water was administered to control rats and 50 mg/kg l-carnitine to rats of l-carnitine treatment groups by intragastric gavage once a day for 30 days. At the end of 30 days, all groups underwent auditory brainstem response testing after administration of intraperitoneal urethane anaesthesia. l-carnitine treatment reduced III, V latencies and I-III, III-V and I-V interpeak latencies (IPL) significantly compared with the control group. l-carnitine treatment improved age-related deterioration in auditory pathways and hence may be a new alternative for the treatment of presbyacusis.
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Affiliation(s)
- A Derin
- Ear, Nose, Throat, Head and Neck Surgery Department, Faculty of Medicine, Akdeniz University, Antalya, Turkey.
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47
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Picciotti P, Torsello A, Wolf FI, Paludetti G, Gaetani E, Pola R. Age-dependent modifications of expression level of VEGF and its receptors in the inner ear. Exp Gerontol 2004; 39:1253-8. [PMID: 15288700 DOI: 10.1016/j.exger.2004.06.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Revised: 05/19/2004] [Accepted: 06/01/2004] [Indexed: 11/25/2022]
Abstract
The mechanisms responsible for age-associated hearing loss are still incompletely characterized. In this study, we used a murine model of age-dependent hearing loss and evaluated whether this condition is associated with vascular modifications of the structures of the inner ear. We used old C57BL/6J mice that are affected by rapid and severe age-related hearing loss, and analyzed the expression pattern of vascular endothelial growth factor (VEGF), a prototypical angiogenic cytokine, and its receptors Flt-1 and Flk-1 in the inner ear. We report for the first time morphological and quantitative data about the expression of these crucial angiogenic molecules in the murine cochlea. We also show that in this animal model, cochlear VEGF expression is significantly reduced as a function of age. Our findings provide new evidence of possible interdependent relationships between aging, VEGF, and presbycusis, suggesting that vascular abnormalities might play a role in aging-associated hearing loss, with potentially important fundamental and clinical implications.
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Affiliation(s)
- Pasqualina Picciotti
- Institute of Otolaryngology, A. Gemelli University Hospital, Università Cattolica del Sacro Cuore School of Medicine, Rome, Italy
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Seidman MD, Ahmad N, Joshi D, Seidman J, Thawani S, Quirk WS. Age-related hearing loss and its association with reactive oxygen species and mitochondrial DNA damage. Acta Otolaryngol 2004:16-24. [PMID: 15219042 DOI: 10.1080/03655230410017823] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Age-related hearing loss, known as presbyacusis, is characterized by the progressive deterioration of auditory sensitivity associated with the aging process and is the leading cause of adult auditory deficiency in the USA. Presbyacusis is described as a progressive, bilateral, high-frequency hearing loss that is manifested on audiometric assessment by a moderately sloping pure tone audiogram. Approximately 23% of the population between 65 and 75 years of age, and 40% of the population older than 75 years of age are affected by this condition. It was estimated in 1980 that 11% of the population was 76 years or older and this number is expected to almost double by the year 2030. When one considers that the population over 65 years of age is experiencing the most accelerated development of hearing loss, the potential socioeconomic ramifications are staggering. Curiously, the frequency of presbyacusis varies across different societies. This discrepancy has been attributed to many factors including genetics, diet, socioeconomic factors, and environmental variables. The purpose of this article is to review the various molecular mechanisms underlying presbyacusis and to offer insights into potential methods of mitigating the effects of aging on hearing impairment.
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Affiliation(s)
- Michael D Seidman
- Department of Otolaryngology-Head & Neck Surgery, Henry Ford Health System, West Bloomfield, Michigan 48323, USA.
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Dai P, Yang W, Jiang S, Gu R, Yuan H, Han D, Guo W, Cao J. Correlation of cochlear blood supply with mitochondrial DNA common deletion in presbyacusis. Acta Otolaryngol 2004; 124:130-6. [PMID: 15072414 DOI: 10.1080/00016480410016586] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To study the relationships between cochlear hypoxia, mitochondrial (mt) DNA4977 deletion and metabolic features of mtDNA in presbyacusis. MATERIAL AND METHODS Sixty-seven temporal bones from a presbyacusis group, an age-matched control group and a young and middle-aged control group were involved in the experiment. Nested and tri-nested polymerase chain reactions (PCRs) were applied to test for the presence of the mtDNA4977 deletion. Computer imaging processing was used to measure blood vessel parameters in the internal acoustic meatus (IAM). RESULTS The mtDNA4977 deletion was detected in 17/34 ears in the presbyacusis group, 4/19 ears in the age-matched control group and 0/14 ears in the young and middle-aged control group. In the presbyacusis group, the lumen of the vasa nervorum of the IAM showed a more severe narrowing in cases with than without the mtDNA4977 deletion. CONCLUSION The high incidence of the mtDNA4977 deletion in the temporal bones of presbyacusis patients suggests a correlation between the mtDNA4977 deletion and presbyacusis. Hypoxia of the cochlea may cause the mtDNA4977 deletion and other mtDNA mutants and furthermore may cause a reduction in mitochondrial oxidative phosphorylation and decreased function of the acoustic neural system. The symptoms of presbyacusis may occur when the function of the acoustic neural system is impaired as a result of abnormal mtDNA metabolism reaching a particular threshold.
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Affiliation(s)
- Pu Dai
- Department of Otolaryngology-Head and Neck Surgery, Chinese PLA General Hospital, Beijing, People's Republic of China
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Abstract
Much of the hearing loss that occurs in old age is likely to be due to the long-term deterioration of the mitochondria in the different structures of the cochlea. The current review surveys some of the basic information on mitochondria and mitochondrial DNA, as a background to their possible involvement in presbyacusis. It is likely that oxygen radicals damage mitochondrial DNA and other components of the mitochondria, such as their proteins and lipids. This further compromises both oxidative phosphorylation and the repair processes in mitochondria, setting up a vicious cycle of degradation. Evidence is presented from inherited point mutations on the possibly most critical sites for mutations in mitochondrial DNA associated with hearing loss. It is suggested that random sorting and clonal expansion of mutations both maintain the integrity of the pool of mitochondrial DNA molecules and give rise to the apoptosis that leads to loss of vulnerable cells, and hence to deafness. It is moreover suggested that apoptosis of the vulnerable cells of the inner ear may to some extent be preventable, or at least delayed.
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Affiliation(s)
- James O Pickles
- Vision, Touch and Hearing Research Centre, School of Biomedical Sciences, University of Queensland, St. Lucia, Australia.
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