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He C, Gai H, Zhao W, Zhang H, Lai L, Ding C, Chen L, Ding J. Advances in the Study of Etiology and Molecular Mechanisms of Sensorineural Hearing Loss. Cell Biochem Biophys 2024; 82:1721-1734. [PMID: 38849694 DOI: 10.1007/s12013-024-01344-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2024] [Indexed: 06/09/2024]
Abstract
Sensorineural hearing loss (SNHL), a multifactorial progressive disorder, results from a complex interplay of genetic and environmental factors, with its underlying mechanisms remaining unclear. Several pathological factors are believed to contribute to SNHL, including genetic factors, ion homeostasis, cell apoptosis, immune inflammatory responses, oxidative stress, hormones, metabolic syndrome, human cytomegalovirus infection, mitochondrial damage, and impaired autophagy. These factors collectively interact and play significant roles in the onset and progression of SNHL. The present review offers a comprehensive overview of the various factors that contribute to SNHL, emphasizes recent developments in understanding its etiology, and explores relevant preventive and intervention measures.
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Affiliation(s)
- Cairong He
- Key laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, 550025, Guizhou, China
| | - Hongcun Gai
- Key laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, 550025, Guizhou, China
| | - Wen Zhao
- Key laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, 550025, Guizhou, China
| | - Haiqin Zhang
- Key laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, 550025, Guizhou, China
| | - Lin Lai
- Key laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, 550025, Guizhou, China
| | - Chenyu Ding
- Key laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, 550025, Guizhou, China
| | - Lin Chen
- Key laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, 550025, Guizhou, China
| | - Jie Ding
- Key laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, 550025, Guizhou, China.
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Maniaci A, La Via L, Lechien JR, Sangiorgio G, Iannella G, Magliulo G, Pace A, Mat Q, Lavalle S, Lentini M. Hearing Loss and Oxidative Stress: A Comprehensive Review. Antioxidants (Basel) 2024; 13:842. [PMID: 39061910 PMCID: PMC11274311 DOI: 10.3390/antiox13070842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 07/05/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024] Open
Abstract
Hearing loss is a prevalent condition affecting millions of people worldwide. Hearing loss has been linked to oxidative stress as a major factor in its onset and progression. The goal of this thorough analysis is to investigate the connection between oxidative stress and hearing loss, with an emphasis on the underlying mechanisms and possible treatments. The review addressed the many forms of hearing loss, the role of reactive oxygen species (ROS) in causing damage to the cochlea, and the auditory system's antioxidant defensive mechanisms. The review also goes over the available data that support the use of antioxidants and other methods to lessen hearing loss brought on by oxidative stress. We found that oxidative stress is implicated in multiple types of hearing loss, including age-related, noise-induced, and ototoxic hearing impairment. The cochlea's unique anatomical and physiological characteristics, such as high metabolic activity and limited blood supply, make it particularly susceptible to oxidative damage. Antioxidant therapies have shown promising results in both animal models and clinical studies for preventing and mitigating hearing loss. Emerging therapeutic approaches, including targeted drug delivery systems and gene therapy, offer new possibilities for addressing oxidative stress in the auditory system. The significance of this review lies in its comprehensive analysis of the intricate relationship between oxidative stress and hearing loss. By synthesizing current knowledge and identifying gaps in understanding, this review provides valuable insights for both researchers and clinicians. It highlights the potential of antioxidant-based interventions and emphasizes the need for further research into personalized treatment strategies. Our findings on oxidative stress mechanisms may also affect clinical practice and future research directions. This review serves as a foundation for developing novel therapeutic approaches and may inform evidence-based strategies for the prevention and treatment of hearing loss, ultimately contributing to improved quality of life for millions affected by this condition worldwide.
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Affiliation(s)
- A. Maniaci
- Faculty of Medicine and Surgery, University of Enna Kore, 94100 Enna, Italy;
- ASP Ragusa-Hospital Giovanni Paolo II, 97100 Ragusa, Italy;
- Otology Study Group, Young Otolaryngologists-International Federation of Otorhinolaryngological Societies, 13005 Paris, France; (J.R.L.); (G.I.); (A.P.); (Q.M.)
| | - L. La Via
- Department of Anaesthesia and Intensive Care, University Hospital Policlinico-San Marco, 95125 Catania, Italy
| | - J. R. Lechien
- Otology Study Group, Young Otolaryngologists-International Federation of Otorhinolaryngological Societies, 13005 Paris, France; (J.R.L.); (G.I.); (A.P.); (Q.M.)
- Department of Human Anatomy and Experimental Oncology, Faculty of Medicine, UMONS Research Institute for Health Sciences and Technology, University of Mons (UMons), 7000 Mons, Belgium
- Department of Otolaryngology-Head & Neck Surgery, Foch Hospital, School of Medicine, UFR Simone Veil, Université Versailles Saint-Quentin-en-Yvelines (Paris Saclay University), 78180 Paris, France
- Department of Otolaryngology-Head & Neck Surgery, EpiCURA Hospital, 7301 Hornu, Belgium
| | - G. Sangiorgio
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy;
| | - G. Iannella
- Otology Study Group, Young Otolaryngologists-International Federation of Otorhinolaryngological Societies, 13005 Paris, France; (J.R.L.); (G.I.); (A.P.); (Q.M.)
- Department of ‘Organi di Senso’, University “Sapienza”, 00185 Rome, Italy;
| | - G. Magliulo
- Department of ‘Organi di Senso’, University “Sapienza”, 00185 Rome, Italy;
| | - A. Pace
- Otology Study Group, Young Otolaryngologists-International Federation of Otorhinolaryngological Societies, 13005 Paris, France; (J.R.L.); (G.I.); (A.P.); (Q.M.)
- Department of ‘Organi di Senso’, University “Sapienza”, 00185 Rome, Italy;
| | - Q. Mat
- Otology Study Group, Young Otolaryngologists-International Federation of Otorhinolaryngological Societies, 13005 Paris, France; (J.R.L.); (G.I.); (A.P.); (Q.M.)
- Department of Otorhinolaryngology, C.H.U. Charleroi, Chaussée de Bruxelles 140, 6042 Charleroi, Belgium
| | - S. Lavalle
- Faculty of Medicine and Surgery, University of Enna Kore, 94100 Enna, Italy;
| | - M. Lentini
- ASP Ragusa-Hospital Giovanni Paolo II, 97100 Ragusa, Italy;
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3
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Vandiver AR, Hoang AN, Herbst A, Lee CC, Aiken JM, McKenzie D, Teitell MA, Timp W, Wanagat J. Nanopore sequencing identifies a higher frequency and expanded spectrum of mitochondrial DNA deletion mutations in human aging. Aging Cell 2023; 22:e13842. [PMID: 37132288 PMCID: PMC10265159 DOI: 10.1111/acel.13842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 05/04/2023] Open
Abstract
Mitochondrial DNA (mtDNA) deletion mutations cause many human diseases and are linked to age-induced mitochondrial dysfunction. Mapping the mutation spectrum and quantifying mtDNA deletion mutation frequency is challenging with next-generation sequencing methods. We hypothesized that long-read sequencing of human mtDNA across the lifespan would detect a broader spectrum of mtDNA rearrangements and provide a more accurate measurement of their frequency. We employed nanopore Cas9-targeted sequencing (nCATS) to map and quantitate mtDNA deletion mutations and develop analyses that are fit-for-purpose. We analyzed total DNA from vastus lateralis muscle in 15 males ranging from 20 to 81 years of age and substantia nigra from three 20-year-old and three 79-year-old men. We found that mtDNA deletion mutations detected by nCATS increased exponentially with age and mapped to a wider region of the mitochondrial genome than previously reported. Using simulated data, we observed that large deletions are often reported as chimeric alignments. To address this, we developed two algorithms for deletion identification which yield consistent deletion mapping and identify both previously reported and novel mtDNA deletion breakpoints. The identified mtDNA deletion frequency measured by nCATS correlates strongly with chronological age and predicts the deletion frequency as measured by digital PCR approaches. In substantia nigra, we observed a similar frequency of age-related mtDNA deletions to those observed in muscle samples, but noted a distinct spectrum of deletion breakpoints. NCATS-mtDNA sequencing allows the identification of mtDNA deletions on a single-molecule level, characterizing the strong relationship between mtDNA deletion frequency and chronological aging.
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Affiliation(s)
- Amy R. Vandiver
- Division of Dermatology, Department of MedicineUCLALos AngelesCaliforniaUSA
- Veterans Administration Greater Los Angeles Healthcare SystemLos AngelesCaliforniaUSA
| | - Austin N. Hoang
- Division of Geriatrics, Department of MedicineUCLALos AngelesCaliforniaUSA
| | - Allen Herbst
- US Geological Survey National Wildlife Health CenterMadisonWisconsinUSA
| | - Cathy C. Lee
- Veterans Administration Greater Los Angeles Healthcare SystemLos AngelesCaliforniaUSA
- Division of Geriatrics, Department of MedicineUCLALos AngelesCaliforniaUSA
| | - Judd M. Aiken
- Department of Agricultural, Food and Nutritional SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - Debbie McKenzie
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - Michael A. Teitell
- Molecular Biology InstituteUniversity of California at Los AngelesLos AngelesCaliforniaUSA
- Department of Pathology and Laboratory Medicine, David Geffen School of MedicineUniversity of California at Los AngelesLos AngelesCaliforniaUSA
- Department of Bioengineering, California NanoSystems Institute, Broad Center for Regenerative Medicine and Stem Cell ResearchUniversity of California at Los AngelesLos AngelesCaliforniaUSA
- Department of Pediatrics, David Geffen School of MedicineUniversity of California at Los AngelesLos AngelesCaliforniaUSA
- Jonsson Comprehensive Cancer Center, David Geffen School of MedicineUniversity of California at Los AngelesLos AngelesCaliforniaUSA
| | - Winston Timp
- Department of Molecular Biology and GeneticsJohns Hopkins University School of MedicineBaltimoreMarylandUSA
- Department of Biomedical EngineeringJohns Hopkins UniversityBaltimoreMarylandUSA
- Department of Genetic MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Jonathan Wanagat
- Veterans Administration Greater Los Angeles Healthcare SystemLos AngelesCaliforniaUSA
- Division of Geriatrics, Department of MedicineUCLALos AngelesCaliforniaUSA
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4
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Tan WJT, Song L. Role of mitochondrial dysfunction and oxidative stress in sensorineural hearing loss. Hear Res 2023; 434:108783. [PMID: 37167889 DOI: 10.1016/j.heares.2023.108783] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 04/19/2023] [Accepted: 04/28/2023] [Indexed: 05/13/2023]
Abstract
Sensorineural hearing loss (SNHL) can either be genetically inherited or acquired as a result of aging, noise exposure, or ototoxic drugs. Although the precise pathophysiological mechanisms underlying SNHL remain unclear, an overwhelming body of evidence implicates mitochondrial dysfunction and oxidative stress playing a central etiological role. With its high metabolic demands, the cochlea, particularly the sensory hair cells, stria vascularis, and spiral ganglion neurons, is vulnerable to the damaging effects of mitochondrial reactive oxygen species (ROS). Mitochondrial dysfunction and consequent oxidative stress in cochlear cells can be caused by inherited mitochondrial DNA (mtDNA) mutations (hereditary hearing loss and aminoglycoside-induced ototoxicity), accumulation of acquired mtDNA mutations with age (age-related hearing loss), mitochondrial overdrive and calcium dysregulation (noise-induced hearing loss and cisplatin-induced ototoxicity), or accumulation of ototoxic drugs within hair cell mitochondria (drug-induced hearing loss). In this review, we provide an overview of our current knowledge on the role of mitochondrial dysfunction and oxidative stress in the development of SNHL caused by genetic mutations, aging, exposure to excessive noise, and ototoxic drugs. We also explore the advancements in antioxidant therapies for the different forms of acquired SNHL that are being evaluated in preclinical and clinical studies.
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Affiliation(s)
- Winston J T Tan
- Department of Surgery (Otolaryngology), Yale University School of Medicine, New Haven, CT, 06510, USA; Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, 1023, New Zealand.
| | - Lei Song
- Department of Surgery (Otolaryngology), Yale University School of Medicine, New Haven, CT, 06510, USA; Department of Otolaryngology - Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China.
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5
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Neyroud AS, Rudinger-Thirion J, Frugier M, Riley LG, Bidet M, Akloul L, Simpson A, Gilot D, Christodoulou J, Ravel C, Sinclair AH, Belaud-Rotureau MA, Tucker EJ, Jaillard S. LARS2 variants can present as premature ovarian insufficiency in the absence of overt hearing loss. Eur J Hum Genet 2023; 31:453-460. [PMID: 36450801 PMCID: PMC10133321 DOI: 10.1038/s41431-022-01252-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 11/07/2022] [Accepted: 11/18/2022] [Indexed: 12/03/2022] Open
Abstract
Premature ovarian insufficiency (POI) affects 1 in 100 women and is a leading cause of female infertility. There are over 80 genes in which variants can cause POI, with these explaining only a minority of cases. Whole exome sequencing (WES) can be a useful tool for POI patient management, allowing clinical care to be personalized to underlying cause. We performed WES to investigate two French sisters, whose only clinical complaint was POI. Surprisingly, they shared one known and one novel likely pathogenic variant in the Perrault syndrome gene, LARS2. Using amino-acylation studies, we established that the novel missense variant significantly impairs LARS2 function. Perrault syndrome is characterized by sensorineural hearing loss in addition to POI. This molecular diagnosis alerted the sisters to the significance of their difficulty in following conversation. Subsequent audiology assessment revealed a mild bilateral hearing loss. We describe the first cases presenting with perceived isolated POI and causative variants in a Perrault syndrome gene. Our study expands the phenotypic spectrum associated with LARS2 variants and highlights the clinical benefit of having a genetic diagnosis, with prediction of potential co-morbidity and prompt and appropriate medical care, in this case by an audiologist for early detection of hearing loss.
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Affiliation(s)
- Anne Sophie Neyroud
- CHU Rennes, Service de Biologie de la Reproduction-CECOS, F-35033, Rennes, France
- Univ Rennes, CHU Rennes, INSERM, EHESP, IRSET (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, F-35000, Rennes, France
| | - Joëlle Rudinger-Thirion
- Université de Strasbourg, Architecture et Réactivité de l'ARN, CNRS, IBMC, Strasbourg, France
| | - Magali Frugier
- Université de Strasbourg, Architecture et Réactivité de l'ARN, CNRS, IBMC, Strasbourg, France
| | - Lisa G Riley
- Rare Diseases Functional Genomics, Kids Research, The Children's Hospital at Westmead and The Children's Medical Research Institute, Sydney, NSW, Australia
- Specialty of Child and Adolescent Health, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Maud Bidet
- Clinique Mutualiste La Sagesse, Service of AMP, 35000, Rennes, France
| | - Linda Akloul
- CHU Rennes, Service de Génétique Clinique, CLAD Ouest, F-35033, Rennes, France
| | - Andrea Simpson
- School of Allied Health, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC, Australia
- College of Health and Human Services, Charles Darwin University, Darwin, NT, Australia
| | - David Gilot
- CHU Rennes, Service de Cytogénétique et Biologie Cellulaire, F-35033, Rennes, France
- INSERM U1242, COSS, Université Rennes 1, F-35032, Rennes, France
| | - John Christodoulou
- Specialty of Child and Adolescent Health, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Célia Ravel
- CHU Rennes, Service de Biologie de la Reproduction-CECOS, F-35033, Rennes, France
- Univ Rennes, CHU Rennes, INSERM, EHESP, IRSET (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, F-35000, Rennes, France
| | - Andrew H Sinclair
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Marc-Antoine Belaud-Rotureau
- CHU Rennes, Service de Biologie de la Reproduction-CECOS, F-35033, Rennes, France
- Univ Rennes, CHU Rennes, INSERM, EHESP, IRSET (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, F-35000, Rennes, France
- School of Allied Health, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC, Australia
| | - Elena J Tucker
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia.
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia.
| | - Sylvie Jaillard
- Univ Rennes, CHU Rennes, INSERM, EHESP, IRSET (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, F-35000, Rennes, France.
- CHU Rennes, Service de Cytogénétique et Biologie Cellulaire, F-35033, Rennes, France.
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Kashio A, Yamada C, Yasuhara K, Kamogashira T, Someya S, Yamasoba T. Taurine, Coenzyme Q 10, and Hydrogen Water Prevents Germanium Dioxide-Induced Mitochondrial Dysfunction and Associated Sensorineural Hearing Loss in mouse. Hear Res 2023; 428:108678. [PMID: 36577362 PMCID: PMC11466212 DOI: 10.1016/j.heares.2022.108678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 11/26/2022] [Accepted: 12/16/2022] [Indexed: 12/23/2022]
Abstract
Mitochondrial dysfunction has been implicated in numerous common diseases as well as aging and plays an important role in the pathogenesis of sensorineural hearing loss (SNHL). In the current study, we showed that supplementation with germanium dioxide (GeO2) in CBA/J mice resulted in SNHL due to the degeneration of the stria vascularis and spiral ganglion, which were associated with down-regulation of mitochondrial respiratory chain associated genes and up-regulation in apoptosis associated genes in the cochlea. Supplementation with taurine, coenzyme Q10, or hydrogen-rich water, attenuated the cochlear degeneration and associated SNHL induced by GeO2. These results suggest that daily supplements or consumption of antioxidants, such as taurine, coenzyme Q10, and hydrogen-rich water, may be a promising intervention to slow SNHL associated with mitochondrial dysfunction.
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Affiliation(s)
- Akinori Kashio
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Chikako Yamada
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Kazuo Yasuhara
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Teru Kamogashira
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Shinichi Someya
- Department of Aging and Geriatric Research, University of Florida, Gainesville, Florida, United States of America
| | - Tatsuya Yamasoba
- Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
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Paciello F, Ripoli C, Fetoni AR, Grassi C. Redox Imbalance as a Common Pathogenic Factor Linking Hearing Loss and Cognitive Decline. Antioxidants (Basel) 2023; 12:antiox12020332. [PMID: 36829891 PMCID: PMC9952092 DOI: 10.3390/antiox12020332] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/23/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023] Open
Abstract
Experimental and clinical data suggest a tight link between hearing and cognitive functions under both physiological and pathological conditions. Indeed, hearing perception requires high-level cognitive processes, and its alterations have been considered a risk factor for cognitive decline. Thus, identifying common pathogenic determinants of hearing loss and neurodegenerative disease is challenging. Here, we focused on redox status imbalance as a possible common pathological mechanism linking hearing and cognitive dysfunctions. Oxidative stress plays a critical role in cochlear damage occurring during aging, as well as in that induced by exogenous factors, including noise. At the same time, increased oxidative stress in medio-temporal brain regions, including the hippocampus, is a hallmark of neurodegenerative disorders like Alzheimer's disease. As such, antioxidant therapy seems to be a promising approach to prevent and/or counteract both sensory and cognitive neurodegeneration. Here, we review experimental evidence suggesting that redox imbalance is a key pathogenetic factor underlying the association between sensorineural hearing loss and neurodegenerative diseases. A greater understanding of the pathophysiological mechanisms shared by these two diseased conditions will hopefully provide relevant information to develop innovative and effective therapeutic strategies.
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Affiliation(s)
- Fabiola Paciello
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Cristian Ripoli
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
- Correspondence: ; Tel.: +39-0630154966
| | - Anna Rita Fetoni
- Unit of Audiology, Department of Neuroscience, Università degli Studi di Napoli Federico II, 80138 Naples, Italy
| | - Claudio Grassi
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
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White K, Someya S. The roles of NADPH and isocitrate dehydrogenase in cochlear mitochondrial antioxidant defense and aging. Hear Res 2023; 427:108659. [PMID: 36493529 PMCID: PMC11446251 DOI: 10.1016/j.heares.2022.108659] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 11/04/2022] [Accepted: 11/23/2022] [Indexed: 11/26/2022]
Abstract
Hearing loss is the third most prevalent chronic health condition affecting older adults. Age-related hearing loss affects one in three adults over 65 years of age and is caused by both extrinsic and intrinsic factors, including genetics, aging, and exposure to noise and toxins. All cells possess antioxidant defense systems that play an important role in protecting cells against these factors. Reduced nicotinamide adenine dinucleotide phosphate (NADPH) serves as a co-factor for antioxidant enzymes such as glutathione reductase and thioredoxin reductase and is produced by glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase 1 (IDH1) or malic enzyme 1 in the cytosol, while in the mitochondria, NADPH is generated from mitochondrial transhydrogenase, glutamate dehydrogenase, malic enzyme 3 or IDH2. There are three isoforms of IDH: cytosolic IDH1, and mitochondrial IDH2 and IDH3. Of these, IDH2 is thought to be the major supplier of NADPH to the mitochondrial antioxidant defense system. The NADP+/NADPH and NAD+/NADH couples are essential for maintaining a large array of biological processes, including cellular redox state, and energy metabolism, mitochondrial function. A growing body of evidence indicates that mitochondrial dysfunction contributes to age-related structural or functional changes of cochlear sensory hair cells and neurons, leading to hearing impairments. In this review, we describe the current understanding of the roles of NADPH and IDHs in cochlear mitochondrial antioxidant defense and aging.
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Affiliation(s)
- Karessa White
- Charlie Brigade Support Medical Company, 2/1 ABCT, United States Army, Fort Riley, KS, USA
| | - Shinichi Someya
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, USA.
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9
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Age-related Activation of Cyclic GMP-AMP synthase-Stimulator of Interferon Genes Signaling in the Auditory System is Associated with Presbycusis in C57BL/6J Male Mice. Neuroscience 2022; 481:73-84. [PMID: 34848262 DOI: 10.1016/j.neuroscience.2021.11.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/29/2021] [Accepted: 11/20/2021] [Indexed: 11/21/2022]
Abstract
Presbycusis, or age-related hearing loss (ARHL), is primarily associated with sensory or transduction nerve cell degeneration in the peripheral and/or central auditory systems. During aging, the auditory system shows mitochondrial dysfunction and increased inflammatory responses. Mitochondrial dysfunction promotes leakage of mitochondrial DNA (mtDNA) into the cytosol, which activates the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway to induce type I interferon and inflammatory responses. However, whether this pathway is involved in the occurrence and development of ARHL is unknown. This study aimed to determine whether there are age-related changes in the levels of cytosolic mtDNA and cGAS-STING pathway activation in the auditory pathway and to explore their relationship with ARHL. The results showed that cGAS-positive immunoreactive cells were observed in the cochlea, inferior colliculus, and auditory cortex. Levels of cytosolic mtDNA, cGAS, STING, phosphorylated interferon regulatory factor 3, and cytokines were significantly increased in the cochlea, inferior colliculus, and auditory cortex of 6-, 9-, and 12-month-old mice compared with 3-month-old mice. These findings suggested that cytosolic mtDNA may play an important role in the pathogenesis of ARHL by activating cGAS-STING-mediated type I interferon and inflammatory responses.
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10
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Herbst A, Lee CC, Vandiver AR, Aiken JM, McKenzie D, Hoang A, Allison D, Liu N, Wanagat J. Mitochondrial DNA deletion mutations increase exponentially with age in human skeletal muscle. Aging Clin Exp Res 2021; 33:1811-1820. [PMID: 32965609 PMCID: PMC7985047 DOI: 10.1007/s40520-020-01698-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/26/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) deletion mutations lead to electron transport chain-deficient cells and age-induced cell loss in multiple tissues and mammalian species. Accurate quantitation of somatic mtDNA deletion mutations could serve as an index of age-induced cell loss. Quantitation of mtDNA deletion molecules is confounded by their low abundance in tissue homogenates, the diversity of deletion breakpoints, stochastic accumulation in single cells, and mosaic distribution between cells. AIMS Translate a pre-clinical assay to quantitate mtDNA deletions for use in human DNA samples, with technical and biological validation, and test this assay on human subjects of different ages. METHODS We developed and validated a high-throughput droplet digital PCR assay that quantitates human mtDNA deletion frequency. RESULTS Analysis of human quadriceps muscle samples from 14 male subjects demonstrated that mtDNA deletion frequency increases exponentially with age-on average, a 98-fold increase from age 20-80. Sequence analysis of amplification products confirmed the specificity of the assay for human mtDNA deletion breakpoints. Titration of synthetic mutation mixtures found a lower limit of detection of at least 0.6 parts per million. Using muscle DNA from 6-month-old mtDNA mutator mice, we measured a 6.4-fold increase in mtDNA deletion frequency (i.e., compared to wild-type mice), biologically validating the approach. DISCUSSION/CONCLUSIONS The exponential increase in mtDNA deletion frequency is concomitant with the known muscle fiber loss and accelerating mortality that occurs with age. The improved assay permits the accurate and sensitive quantification of deletion mutations from DNA samples and is sufficient to measure changes in mtDNA deletion mutation frequency in healthy individuals across the lifespan and, therefore, patients with suspected mitochondrial diseases.
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Affiliation(s)
- Allen Herbst
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB, Canada
| | - Cathy C Lee
- Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, USA
- Division of Geriatrics, Department of Medicine, UCLA, Los Angeles, CA, USA
| | - Amy R Vandiver
- Division of Dermatology, Department of Medicine, UCLA, 10945 Le Conte Ave, Suite 2339, Los Angeles, CA, 90095, USA
| | - Judd M Aiken
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB, Canada
| | - Debbie McKenzie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Austin Hoang
- Division of Geriatrics, Department of Medicine, UCLA, Los Angeles, CA, USA
| | - David Allison
- Department of Epidemiology and Biostatistics, Indiana University Bloomington, Bloomington, IN, USA
| | - Nianjun Liu
- Department of Epidemiology and Biostatistics, Indiana University Bloomington, Bloomington, IN, USA
| | - Jonathan Wanagat
- Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, USA.
- Division of Geriatrics, Department of Medicine, UCLA, Los Angeles, CA, USA.
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11
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Abstract
Mitochondrial dysfunction has been suggested to be a risk factor for sensorineural hearing loss (SNHL) induced by aging, noise, ototoxic drugs, and gene. Reactive oxygen species (ROS) are mainly derived from mitochondria, and oxidative stress induced by ROS contributes to cochlear damage as well as mitochondrial DNA mutations, which may enhance the sensitivity and severity of hearing loss and disrupt ion homeostasis (e.g., Ca2+ homeostasis). The formation and accumulation of ROS further undermine mitochondrial components and ultimately lead to apoptosis and necrosis. SIRT3–5, located in mitochondria, belong to the family of sirtuins, which are highly conserved deacetylases dependent on nicotinamide adenine dinucleotide (NAD+). These deacetylases regulate diverse cellular biochemical activities. Recent studies have revealed that mitochondrial sirtuins, especially SIRT3, modulate ROS levels in hearing loss pathologies. Although the precise functions of SIRT4 and SIRT5 in the cochlea remain unclear, the molecular mechanisms in other tissues indicate a potential protective effect against hearing loss. In this review, we summarize the current knowledge regarding the role of mitochondrial dysfunction in hearing loss, discuss possible functional links between mitochondrial sirtuins and SNHL, and propose a perspective that SIRT3–5 have a positive effect on SNHL.
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12
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Oishi T, Matsumaru D, Ota N, Kitamura H, Zhang T, Honkura Y, Katori Y, Motohashi H. Activation of the NRF2 pathway in Keap1-knockdown mice attenuates progression of age-related hearing loss. NPJ Aging Mech Dis 2020; 6:14. [PMID: 33318486 PMCID: PMC7736866 DOI: 10.1038/s41514-020-00053-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 11/12/2020] [Indexed: 12/21/2022] Open
Abstract
Age-related hearing loss (AHL) is a progressive sensorineural hearing loss in elderly people. Although no prevention or treatments have been established for AHL, recent studies have demonstrated that oxidative stress is closely related to pathogenesis of AHL, suggesting that suppression of oxidative stress leads to inhibition of AHL progression. NRF2 is a master transcription factor that regulates various antioxidant proteins and cytoprotection factors. To examine whether NRF2 pathway activation prevents AHL, we used Keap1-knockdown (Keap1FA/FA) mice, in which KEAP1, a negative regulator of NRF2, is decreased, resulting in the elevation of NRF2 activity. We compared 12-month-old Keap1FA/FA mice with age-matched wild-type (WT) mice in the same breeding colony. In the Keap1FA/FA mice, the expression levels of multiple NRF2 target genes were verified to be significantly higher than the expression levels of these genes in the WT mice. Histological analysis showed that cochlear degeneration at the apical and middle turns was ameliorated in the Keap1FA/FA mice. Auditory brainstem response (ABR) thresholds in the Keap1FA/FA mice were significantly lower than those in the WT mice, in particular at low-mid frequencies. Immunohistochemical detection of oxidative stress markers suggested that oxidative stress accumulation was attenuated in the Keap1FA/FA cochlea. Thus, we concluded that NRF2 pathway activation protects the cochlea from oxidative damage during aging, in particular at the apical and middle turns. KEAP1-inhibiting drugs and phytochemicals are expected to be effective in the prevention of AHL.
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Affiliation(s)
- Tetsuya Oishi
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.,Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Daisuke Matsumaru
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Nao Ota
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Hiroshi Kitamura
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Tianxiang Zhang
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Yohei Honkura
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Yukio Katori
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Hozumi Motohashi
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
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13
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Perkins G, Lee JH, Park S, Kang M, Perez-Flores MC, Ju S, Phillips G, Lysakowski A, Gratton MA, Yamoah EN. Altered Outer Hair Cell Mitochondrial and Subsurface Cisternae Connectomics Are Candidate Mechanisms for Hearing Loss in Mice. J Neurosci 2020; 40:8556-8572. [PMID: 33020216 PMCID: PMC7605424 DOI: 10.1523/jneurosci.2901-19.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 09/21/2020] [Accepted: 09/24/2020] [Indexed: 11/21/2022] Open
Abstract
Organelle crosstalk is vital for cellular functions. The propinquity of mitochondria, ER, and plasma membrane promote regulation of multiple functions, which include intracellular Ca2+ flux, and cellular biogenesis. Although the purposes of apposing mitochondria and ER have been described, an understanding of altered organelle connectomics related to disease states is emerging. Since inner ear outer hair cell (OHC) degeneration is a common trait of age-related hearing loss, the objective of this study was to investigate whether the structural and functional coupling of mitochondria with subsurface cisternae (SSC) was affected by aging. We applied functional and structural probes to equal numbers of male and female mice with a hearing phenotype akin to human aging. We discovered the polarization of cristae and crista junctions in mitochondria tethered to the SSC in OHCs. Aging was associated with SSC stress and decoupling of mitochondria with the SSC, mitochondrial fission/fusion imbalance, a remarkable reduction in mitochondrial and cytoplasmic Ca2+ levels, reduced K+-induced Ca2+ uptake, and marked plasticity of cristae membranes. A model of structure-based ATP production predicts profound energy stress in older OHCs. This report provides data suggesting that altered membrane organelle connectomics may result in progressive hearing loss.
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Affiliation(s)
- Guy Perkins
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, California 92093
| | | | | | | | | | - Saeyeon Ju
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, California 92093
| | - Grady Phillips
- Washington University School of Medicine, St. Louis, Missouri 63110
| | - Anna Lysakowski
- Departments of Anatomy and Cell Biology and Otolaryngology, University of Illinois at Chicago, Chicago, Illinois 60612
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14
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Keithley EM. Pathology and mechanisms of cochlear aging. J Neurosci Res 2020; 98:1674-1684. [PMID: 31066107 PMCID: PMC7496655 DOI: 10.1002/jnr.24439] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/22/2019] [Accepted: 04/23/2019] [Indexed: 12/21/2022]
Abstract
Presbycusis, or age-related hearing loss (ARHL), occurs in most mammals with variations in the age of onset, rate of decline, and magnitude of degeneration in the central nervous system and inner ear. The affected cochlear structures include the stria vascularis and its vasculature, spiral ligament, sensory hair cells and auditory neurons. Dysfunction of the stria vascularis results in a reduced endocochlear potential. Without this potential, the cochlear amplification provided by the electro-motility of the outer hair cells is insufficient, and a high-frequency hearing-loss results. Degeneration of the sensory cells, especially the outer hair cells also leads to hearing loss due to lack of amplification. Neuronal degeneration, another hallmark of ARHL, most likely underlies difficulties with speech discrimination, especially in noisy environments. Noise exposure is a major cause of ARHL. It is well-known to cause sensory cell degeneration, especially the outer hair cells at the high frequency end of the cochlea. Even loud, but not uncomfortable, sound levels can lead to synaptopathy and ultimately neuronal degeneration. Even in the absence of a noisy environment, aged cells degenerate. This pathology most likely results from damage to mitochondria and contributes to degenerative changes in the stria vascularis, hair cells, and neurons. The genetic underpinnings of ARHL are still unknown and most likely involve various combinations of genes. At present, the only effective strategy for reducing ARHL is prevention of noise exposure. If future strategies can improve mitochondrial activity and reduce oxidative damage in old age, these should also bring relief.
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Affiliation(s)
- Elizabeth M. Keithley
- Division of Otolaryngology ‐ Head and Neck SurgeryUniversity of CaliforniaSan DiegoCalifornia
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15
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Li Q, Xiang YH, Liang XJ, Zhang Y, Zhao PP, Wang M, Bao XM, Zhu XB, Deng AC. Expression of G9a in Auditory Cortex Is Downregulated in a Rat Model of Age-Related Hearing Loss. J Mol Neurosci 2020; 71:409-418. [PMID: 32671696 DOI: 10.1007/s12031-020-01663-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/08/2020] [Indexed: 01/11/2023]
Abstract
G9a is essential for dendritic plasticity and is associated with neurological disorders. The possible relationship between age-related hearing loss and G9a expression in the auditory cortex has not been fully explored. This study aimed to understand the expression patterns of G9a-mediated histone methylations in the auditory cortex during aging. Using immunofluorescence and western blotting, we demonstrated that a significant reduction in G9a expression observed in the auditory cortex of 24-month-old rats compared to 3-month-old rats, was associated with remarkable hearing threshold elevation and hair cell loss. Correspondingly, histone H3 lysine 9 (H3K9) mono- and dimethylation (marked by H3K9me1 and H3K9me2, respectively), which were regulated by G9a activity, also evidently decreased during aging. These findings, which merit further investigation, suggest a possible association between G9a-mediated histone methylations and central age-related hearing disorders.
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Affiliation(s)
- Qian Li
- Department of Otolaryngology Head and Neck Surgery, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Yang-Hong Xiang
- Department of Otolaryngology Head and Neck Surgery, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Xiao-Jun Liang
- Department of Otolaryngology Head and Neck Surgery, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Yun Zhang
- Department of Otolaryngology Head and Neck Surgery, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Peng-Peng Zhao
- Department of Otolaryngology Head and Neck Surgery, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Min Wang
- Department of Otolaryngology Head and Neck Surgery, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Xiao-Min Bao
- Department of Otolaryngology Head and Neck Surgery, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Xian-Bai Zhu
- Department of Otolaryngology Head and Neck Surgery, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - An-Chun Deng
- Department of Otolaryngology Head and Neck Surgery, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China.
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16
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Kim YY, Chao JR, Kim C, Kim B, Thi-Thanh Nguyen P, Jung H, Chang J, Lee JH, Suh JG. Hearing loss through apoptosis of the spiral ganglion neurons in apolipoprotein E knockout mice fed with a western diet. Biochem Biophys Res Commun 2020; 523:692-698. [PMID: 31948760 DOI: 10.1016/j.bbrc.2019.12.100] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 12/21/2019] [Indexed: 01/11/2023]
Abstract
Age-related hearing loss (ARHL) is a neurodegenerative disease associated with an aged population. ARHL is influenced by biological factors such as aging, sex difference, and atherosclerosis. The mechanisms of ARHL caused by atherosclerosis have not been previously determined in apolipoprotein E knockout (ApoE KO) male mice. To investigate the onset and cause of the hearing loss, ApoE KO male mice were treated with a western diet (ApoE KO-WD) for 16 weeks. The lipid profile, atherosclerotic plaques throughout the aorta, and auditory brainstem response (ABR) thresholds were measured in the ApoE KO-WD male mice. The expression of S100 calcium-binding protein B (S100B), a neuronal damage biomarker, was also observed. Reactive oxygen species (ROS) and apoptosis rates were detected in the cochlea of the ApoE KO male mice. Atherosclerotic plaques on the aorta and ABR thresholds were significantly increased in the ApoE KO-WD male mice at 24 weeks of age. ABR thresholds had a statistically significant positive correlation with the area of atherosclerotic plaques (r = 0.783, p = 0.013) in male mice at 24 weeks of age. S100B protein expression and the dihydroethidium (DHE) reaction to ROS in the cochlear spiral ganglion neurons (SGNs) were significantly increased in the ApoE KO and ApoE KO-WD male mice. Cells positive for active caspase-3 and terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) in the SGNs were significantly increased in ApoE KO-WD male mice indicating an increased rate of cellular apoptosis. In conclusion, ROS in the SGNs were activated by increased S100B expression in ApoE KO-WD male mice, and this resulted in an increased apoptosis rate. Thus, hearing loss began at 16 weeks in ApoE KO-WD male mice. Our results suggest that the ApoE KO-WD male mice are a suitable animal model for studying ARHL associated with exacerbated atherosclerosis.
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Affiliation(s)
- Yoo Yeon Kim
- Department of Medical Genetics, College of Medicine, Hallym University, Chuncheon, 24252, Republic of Korea
| | - Janet Ren Chao
- Division of Otolaryngology, Department of Surgery, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Chulho Kim
- Department of Neurology, Hallym University College of Medicine, Chuncheon, 24252, Republic of Korea
| | - Boyoung Kim
- Department of Medical Genetics, College of Medicine, Hallym University, Chuncheon, 24252, Republic of Korea
| | - Phuong Thi-Thanh Nguyen
- Department of Medical Genetics, College of Medicine, Hallym University, Chuncheon, 24252, Republic of Korea
| | - Harry Jung
- Institute of New Frontier Research Team, Hallym University College of Medicine, Chuncheon, 24252, Republic of Korea
| | - Jiwon Chang
- Department of Otorhinolaryngology-Head and Neck Surgery, Hallym University College of Medicine, Chuncheon, 24252, Republic of Korea
| | - Jun Ho Lee
- Institute of New Frontier Research Team, Hallym University College of Medicine, Chuncheon, 24252, Republic of Korea; Department of Otorhinolaryngology-Head and Neck Surgery, Hallym University College of Medicine, Chuncheon, 24252, Republic of Korea.
| | - Jun Gyo Suh
- Department of Medical Genetics, College of Medicine, Hallym University, Chuncheon, 24252, Republic of Korea.
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17
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Grover R, Burse SA, Shankrit S, Aggarwal A, Kirty K, Narta K, Srivastav R, Ray AK, Malik G, Vats A, Motiani RK, Thukral L, Roy SS, Bhattacharya S, Sharma R, Natarajan K, Mukerji M, Pandey R, Gokhale RS, Natarajan VT. Myg1 exonuclease couples the nuclear and mitochondrial translational programs through RNA processing. Nucleic Acids Res 2019; 47:5852-5866. [PMID: 31081026 PMCID: PMC6582341 DOI: 10.1093/nar/gkz371] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 04/12/2019] [Accepted: 04/30/2019] [Indexed: 01/25/2023] Open
Abstract
Semi-autonomous functioning of mitochondria in eukaryotic cell necessitates coordination with nucleus. Several RNA species fine-tune mitochondrial processes by synchronizing with the nuclear program, however the involved components remain enigmatic. In this study, we identify a widely conserved dually localized protein Myg1, and establish its role as a 3′-5′ RNA exonuclease. We employ mouse melanoma cells, and knockout of the Myg1 ortholog in Saccharomyces cerevisiae with complementation using human Myg1 to decipher the conserved role of Myg1 in selective RNA processing. Localization of Myg1 to nucleolus and mitochondrial matrix was studied through imaging and confirmed by sub-cellular fractionation studies. We developed Silexoseqencing, a methodology to map the RNAse trail at single-nucleotide resolution, and identified in situ cleavage by Myg1 on specific transcripts in the two organelles. In nucleolus, Myg1 processes pre-ribosomal RNA involved in ribosome assembly and alters cytoplasmic translation. In mitochondrial matrix, Myg1 processes 3′-termini of the mito-ribosomal and messenger RNAs and controls translation of mitochondrial proteins. We provide a molecular link to the possible involvement of Myg1 in chronic depigmenting disorder vitiligo. Our study identifies a key component involved in regulating spatially segregated organellar RNA processing and establishes the evolutionarily conserved ribonuclease as a coordinator of nucleo-mitochondrial crosstalk.
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Affiliation(s)
- Ritika Grover
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India.,Academy of Scientific and Innovative Research, Rafi Marg, New Delhi, India
| | - Shaunak A Burse
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India.,Academy of Scientific and Innovative Research, Rafi Marg, New Delhi, India
| | - Shambhavi Shankrit
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Ayush Aggarwal
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India.,Academy of Scientific and Innovative Research, Rafi Marg, New Delhi, India
| | - Kritika Kirty
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Kiran Narta
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Rajpal Srivastav
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Ashwini Kumar Ray
- School of environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Garima Malik
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Archana Vats
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Rajender K Motiani
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Lipi Thukral
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Soumya Sinha Roy
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Sudha Bhattacharya
- School of environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Rakesh Sharma
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | | | - Mitali Mukerji
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Rajesh Pandey
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India
| | - Rajesh S Gokhale
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India.,National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India
| | - Vivek T Natarajan
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi, India.,Academy of Scientific and Innovative Research, Rafi Marg, New Delhi, India
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18
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The nuclear transcription factor FoxG1 affects the sensitivity of mimetic aging hair cells to inflammation by regulating autophagy pathways. Redox Biol 2019; 28:101364. [PMID: 31731101 PMCID: PMC6920089 DOI: 10.1016/j.redox.2019.101364] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/22/2019] [Accepted: 10/27/2019] [Indexed: 12/18/2022] Open
Abstract
Inflammation is a self-defense response to protect individuals from infection and tissue damage, but excessive or persistent inflammation can have adverse effects on cell survival. Many individuals become especially susceptible to chronic-inflammation-induced sensorineural hearing loss as they age, but the intrinsic molecular mechanism behind aging individuals' increased risk of hearing loss remains unclear. FoxG1 (forkhead box transcription factor G1) is a key transcription factor that plays important roles in hair cell survival through the regulation of mitochondrial function, but how the function of FoxG1 changes during aging and under inflammatory conditions is unknown. In this study, we first found that FoxG1 expression and autophagy both increased gradually in the low concentration lipopolysaccharide (LPS)-induced inflammation model, while after high concentration of LPS treatment both FoxG1 expression and autophagy levels decreased as the concentration of LPS increased. We then used siRNA to downregulate Foxg1 expression in hair cell-like OC-1 cells and found that cell death and apoptosis were significantly increased after LPS injury. Furthermore, we used d-galactose (D-gal) to create an aging model with hair cell-like OC-1 cells and cochlear explant cultures in vitro and found that the expression of Foxg1 and the level of autophagy were both decreased after D-gal and LPS co-treatment. Lastly, we knocked down the expression of Foxg1 under aged inflammation conditions and found increased numbers of dead and apoptotic cells. Together these results suggest that FoxG1 affects the sensitivity of mimetic aging hair cells to inflammation by regulating autophagy pathways.
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19
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Abstract
Age-related hearing loss (ARHL) is the most prevalent sensory deficit in the elderly. This progressive hearing impairment leads to social isolation and is also associated with comorbidities, such as frailty, falls, and late-onset depression. Moreover, there is a growing evidence linking it with cognitive decline and increased risk of dementia. Given the large social and welfare burden that results from ARHL, and because ARHL is potentially a modifiable risk factor for dementia, there is an urgent need for therapeutic interventions to ameliorate age-related auditory decline. However, a prerequisite for design of therapies is knowledge of the underlying molecular mechanisms. Currently, our understanding of ARHL is very limited. Here, we review recent findings from research into ARHL from both human and animal studies and discuss future prospects for advances in our understanding of genetic susceptibility, pathology, and potential therapeutic approaches in ARHL.
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Affiliation(s)
- Michael R Bowl
- Mammalian Genetics Unit, MRC Harwell Institute, Oxford OX11 0RD, United Kingdom
| | - Sally J Dawson
- UCL Ear Institute, University College London, London WC1X 8EE, United Kingdom
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20
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Increased burden of mitochondrial DNA deletions and point mutations in early-onset age-related hearing loss in mitochondrial mutator mice. Exp Gerontol 2019; 125:110675. [PMID: 31344454 DOI: 10.1016/j.exger.2019.110675] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 07/14/2019] [Accepted: 07/20/2019] [Indexed: 11/20/2022]
Abstract
Mitochondrial DNA (mtDNA) mutations are thought to have a causal role in a variety of age-related neurodegenerative diseases, including age-related hearing loss (AHL). In the current study, we investigated the roles of mtDNA deletions and point mutations in AHL in mitochondrial mutator mice (Polgmut/mut) that were backcrossed onto CBA/CaJ mice, a well-established model of late-onset AHL. mtDNA deletions accumulated significantly with age in the inner ears of Polgmut/mut mice, while there were no differences in mtDNA deletion frequencies in the inner ears between 5 and 17 months old Polg+/+ mice or 5 months old Polg+/+ and Polgmut/mut mice. mtDNA deletions also accumulated significantly in the inner ears of CBA/CaJ mice during normal aging. In contrast, 5 months old Polgmut/mut mice displayed a 238-fold increase in mtDNA point mutation frequencies in the inner ears compared to age-matched Polg+/+ mice, but there were no differences in mtDNA point mutation frequencies in the inner ears between 5 and 17 months old Polgmut/mut mice. Seventeen-month-old Polgmut/mut mice also displayed early-onset severe hearing loss associated with a significant reduction in neural output of the cochlea, while age-matched Polg+/+ mice displayed little or no hearing impairment. Consistent with the physiological and mtDNA deletion test result, 17-month-old Polgmut/mut mice displayed a profound loss of spiral ganglion neurons in the cochlea. Thus, our data suggest that a higher burden of mtDNA point mutations from a young age and age-related accumulation of mtDNA deletions likely contribute to early-onset AHL in mitochondrial mutator mice.
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21
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Fujimoto C, Yamasoba T. Mitochondria-Targeted Antioxidants for Treatment of Hearing Loss: A Systematic Review. Antioxidants (Basel) 2019; 8:E109. [PMID: 31022870 PMCID: PMC6523236 DOI: 10.3390/antiox8040109] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 01/22/2023] Open
Abstract
Mitochondrial dysfunction is associated with the etiologies of sensorineural hearing loss, such as age-related hearing loss, noise- and ototoxic drug-induced hearing loss, as well as hearing loss due to mitochondrial gene mutation. Mitochondria are the main sources of reactive oxygen species (ROS) and ROS-induced oxidative stress is involved in cochlear damage. Moreover, the release of ROS causes further damage to mitochondrial components. Antioxidants are thought to counteract the deleterious effects of ROS and thus, may be effective for the treatment of oxidative stress-related diseases. The administration of mitochondria-targeted antioxidants is one of the drug delivery systems targeted to mitochondria. Mitochondria-targeted antioxidants are expected to help in the prevention and/or treatment of diseases associated with mitochondrial dysfunction. Of the various mitochondria-targeted antioxidants, the protective effects of MitoQ and SkQR1 against ototoxicity have been previously evaluated in animal models and/or mouse auditory cell lines. MitoQ protects against both gentamicin- and cisplatin-induced ototoxicity. SkQR1 also provides auditory protective effects against gentamicin-induced ototoxicity. On the other hand, decreasing effect of MitoQ on gentamicin-induced cell apoptosis in auditory cell lines has been controversial. No clinical studies have been reported for otoprotection using mitochondrial-targeted antioxidants. High-quality clinical trials are required to reveal the therapeutic effect of mitochondria-targeted antioxidants in terms of otoprotection in patients.
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Affiliation(s)
- Chisato Fujimoto
- Department of Otolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
- Department of Otolaryngology, Tokyo Teishin Hospital, 2-14-23, Fujimi, Chiyoda-ku, Tokyo 102-8798, Japan.
| | - Tatsuya Yamasoba
- Department of Otolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
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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] [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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Tan WJT, Song L, Graham M, Schettino A, Navaratnam D, Yarbrough WG, Santos-Sacchi J, Ivanova AV. Novel Role of the Mitochondrial Protein Fus1 in Protection from Premature Hearing Loss via Regulation of Oxidative Stress and Nutrient and Energy Sensing Pathways in the Inner Ear. Antioxid Redox Signal 2017; 27:489-509. [PMID: 28135838 PMCID: PMC5564041 DOI: 10.1089/ars.2016.6851] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
AIMS Acquired hearing loss is a worldwide epidemic that affects all ages. It is multifactorial in etiology with poorly characterized molecular mechanisms. Mitochondria are critical components in hearing. Here, we aimed to identify the mechanisms of mitochondria-dependent hearing loss using Fus1 KO mice, our novel model of mitochondrial dysfunction/oxidative stress. RESULTS Using auditory brainstem responses (ABRs), we characterized the Fus1 KO mouse as a novel, clinically relevant model of age-related hearing loss (ARHL) of metabolic etiology. We demonstrated early decline of the endocochlear potential (EP) that may occur due to severe mitochondrial and vascular pathologies in the Fus1 KO cochlear stria vascularis. We showed that pathological alterations in antioxidant (AO) and nutrient and energy sensing pathways (mTOR and PTEN/AKT) occur in cochleae of young Fus1 KO mice before major hearing loss. Importantly, short-term AO treatment corrected pathological molecular changes, while longer AO treatment restored EP, improved ABR parameters, restored mitochondrial structure, and delayed the development of hearing loss in the aging mouse. INNOVATION Currently, no molecular mechanisms linked to metabolic ARHL have been identified. We established pathological and molecular mechanisms that link the disease to mitochondrial dysfunction and oxidative stress. CONCLUSION Since chronic mitochondrial dysfunction is common in many patients, it could lead to developing hearing loss that can be alleviated/rescued by AO treatment. Our study creates a framework for clinical trials and introduces the Fus1 KO model as a powerful platform for developing novel therapeutic strategies to prevent/delay hearing loss associated with mitochondrial dysfunction. Antioxid. Redox Signal. 27, 489-509.
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Affiliation(s)
- Winston J T Tan
- 1 Department of Surgery, Section of Otolaryngology, Yale University School of Medicine , New Haven, Connecticut
| | - Lei Song
- 2 Department of Otolaryngology-Head and Neck Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai, China .,3 Ear Institute, Shanghai Jiao Tong University School of Medicine , Shanghai, China .,4 Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases , Shanghai, China
| | - Morven Graham
- 5 CCMI EM Core Facility, Yale University School of Medicine , New Haven, Connecticut
| | | | - Dhasakumar Navaratnam
- 7 Department of Neurology, Yale University School of Medicine , New Haven, Connecticut.,8 Department of Neuroscience, Yale University School of Medicine , New Haven, Connecticut
| | - Wendell G Yarbrough
- 1 Department of Surgery, Section of Otolaryngology, Yale University School of Medicine , New Haven, Connecticut.,9 Department of Pathology, Yale University School of Medicine , New Haven, Connecticut
| | - Joseph Santos-Sacchi
- 1 Department of Surgery, Section of Otolaryngology, Yale University School of Medicine , New Haven, Connecticut.,8 Department of Neuroscience, Yale University School of Medicine , New Haven, Connecticut.,10 Department of Cellular and Molecular Physiology, Yale University School of Medicine , New Haven, Connecticut
| | - Alla V Ivanova
- 1 Department of Surgery, Section of Otolaryngology, Yale University School of Medicine , New Haven, Connecticut
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Xu Y, Liu L, Nakamura A, Someya S, Miyakawa T, Tanokura M. Studies on the regulatory mechanism of isocitrate dehydrogenase 2 using acetylation mimics. Sci Rep 2017; 7:9785. [PMID: 28852116 PMCID: PMC5575304 DOI: 10.1038/s41598-017-10337-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 08/08/2017] [Indexed: 01/29/2023] Open
Abstract
Mitochondrial isocitrate dehydrogenase 2 (IDH2) converts NADP+ to NADPH and promotes regeneration of reduced glutathione (GSH) by supplying NADPH to glutathione reductase or thioredoxin reductase. We have previously shown that under calorie restriction, mitochondrial deacetylase Sirt3 deacetylates and activates IDH2, thereby regulating the mitochondrial glutathione antioxidant defense system in mice. To investigate the regulatory mechanism of mIDH2 (mouse mitochondrial IDH2), we used lysine-to-glutamine (KQ) mutants to mimic acetylated lysines and screened 15 KQ mutants. Among these mutants, the activities of the K256Q and K413Q proteins were less than 50% of the wild-type value. We then solved the crystal structures of the wild-type mIDH2 and the K256Q mutant proteins, revealing conformational changes in the substrate-binding pocket. Structural data suggested that positively charged Lys256 was important in stabilizing the pocket because it repelled a lysine cluster on the other side. Glutamine (or acetylated lysine) was neutral and thus caused the pocket size to decrease, which might be the main reason for the lower activity of the K256Q mutant. Together, our data provide the first structure of an acetylation mimic of mIDH2 and new insights into the regulatory mechanism of acetylation of mIDH2.
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Affiliation(s)
- Yuqun Xu
- Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Lingwen Liu
- Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Akira Nakamura
- Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Shinichi Someya
- Departments of Aging and Geriatric Research, University of Florida, Gainesville, Florida, 32610-0143, United States of America
| | - Takuya Miyakawa
- Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Masaru Tanokura
- Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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Sang L, Zheng T, Min L, Zhang X, Ma X, Entenman S, Su Y, Zheng Q. Otoprotective effects of ethosuximide in NOD/LtJ mice with age-related hearing loss. Int J Mol Med 2017; 40:146-154. [PMID: 28560432 PMCID: PMC5466398 DOI: 10.3892/ijmm.2017.3004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 05/12/2017] [Indexed: 11/30/2022] Open
Abstract
Despite long-term efforts to elucidate the mechanisms responsible for age-related hearing loss (AHL), there is currently no available treatment strategy able to provide a cure. Apoptotic cell death, including that of hair cells and spiral ganglion neurons (SGNs) in the cochlea has been proposed to be the classic theory behind the development of AHL. As calcium signaling plays key roles in signal transduction in apoptosis, in this study, we selected ethosuximide, which is able to block T-type calcium (Ca2+ion) channels, suppressing Ca2+. We hypothesized that the apoptotic pathway may be blocked through the inhibition of T-type Ca2+ channels in cochlear cells in NOD/LtJ mice. NOD/LtJ mice were divided into 2 groups as follows: the ethosuximide-treated and untreated (control) groups. Ethosuximide was administered by intraperitoneal injection every other day from post-natal day seven (P7) until the mice were 8 weeks of age. Following treatment, auditory-evoked brainstem response (ABR) thresholds and distortion product oto-acoustic emission (DPOAE) of the mice in the 2 groups were measured at different time points. Morphometric analysis and the expression of genes involved in the T-type Ca2+-mediated apoptotic pathway were monitored. The ABR and DPOAE results revealed that the NOD/LtJ mice exhibited early-onset and rapidly progressive AHL. A histological examination revealed that hair cell degeneration coincided with the progression of hearing loss. Hair cell and SGN was were significantly lower and auditory function was significantly improved in the ethosuximide-treated group compared to the untreated group. Our data thus indicate that ethosuximide prevents the degeneration of cochlear cells by regulating the expression of genes in apoptotic pathways. Our findings suggest that activating the T-type Ca2+ channel and downstream genes may be key pathological mechanisms responsible for AHL in NOD/LtJ mice.
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Affiliation(s)
- Lu Sang
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Tihua Zheng
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Lingqian Min
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Xiaolin Zhang
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Xiufang Ma
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Shami Entenman
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, OH 44106-4952, USA
| | - Yipeng Su
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Qingyin Zheng
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, OH 44106-4952, USA
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Reduced expression of citrate synthase leads to excessive superoxide formation and cell apoptosis. Biochem Biophys Res Commun 2017; 485:388-394. [PMID: 28216161 DOI: 10.1016/j.bbrc.2017.02.067] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 02/13/2017] [Indexed: 02/04/2023]
Abstract
A/J mice are a mouse model of age-related hearing loss. It has been demonstrated that a mutation in gene of citrate synthase (CS) contributes to the early onset of hearing loss occurring at about one month of age. To understand the effects of a decreased CS activity that results from the mutation in Cs gene on hearing loss in A/J mice, human kidney cell line (293T) was transiently transfected with short hairpin RNA for Cs (shRNA-Cs) to reduce expression of CS. In comparison with those of cells transfected with a scrambled sequence (shRNA-NC), the oxygen consumption rate and adenosine trisphosphate (ATP) production level were decreased in 293T cells transfected with shRNA-Cs. Meanwhile, excessive superoxide production was induced as determined by mitochondrial superoxide formation assay (MitoSOX) and superoxide dismutase 2 (SOD2) detection. Moreover, the expression levels of BIP (binding immunoglobulin protein) and CHOP (CCAAT/enhancer-binding protein-homologous protein), markers of endoplasmic reticulum stress, were upregulated. Furthermore, apoptosis related molecule caspase-3 and the mitochondrial membrane potential were reduced. It is therefore concluded that downregulation of Cs expression in 293T cells leads to low level of ATP production, excessive superoxide formation and cell apoptosis, which implies a possible mechanism for hearing loss in A/J mice.
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Tavanai E, Mohammadkhani G. Role of antioxidants in prevention of age-related hearing loss: a review of literature. Eur Arch Otorhinolaryngol 2016; 274:1821-1834. [PMID: 27858145 DOI: 10.1007/s00405-016-4378-6] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 11/08/2016] [Indexed: 01/21/2023]
Abstract
Age-related hearing loss (ARHL), also known as presbycusis, is one of the most prevalent chronic degenerative conditions. It is characterized by a decline in auditory function. ARHL is caused by the interaction of multiple factors, including cochlear aging, environment, genetic predisposition, and health comorbidities. The primary pathology of ARHL includes the hair cells loss, stria vascularis atrophy, and loss of spiral ganglion neurons as well as the changes in central auditory pathways. The research to date suggests that oxidative stress and mitochondrial DNA deletion (mtDNA) play a major role in pathophysiology of ARHL. Therefore, similar to other otological conditions, several studies have also showed that antioxidants can slow ARHL, but some also indicate that antioxidant therapy is not a magic elixir that will prevent or treat hearing loss associated with aging completely, but why? All available clinical trials, including animal and human studies, in English language that examined the protective effects of antioxidants against ARHL were reviewed. Materials were obtained by searching ELSEVIER, PubMed, Scopus, Web of knowledge, Google Scholar databases, Clinical trials, and Cochrane database of systematic reviews. Although ARHL has been shown to be slowed by supplementation with antioxidants, particularly in laboratory animals, a few studies have investigated the effect of interventions against ARHL in humans. High-quality clinical trials are needed to investigate if ARHL can be delayed or prevented in humans. However, it seems that targeting several cell-death pathways is better than targeting the only oxidative stress pathway.
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Affiliation(s)
- Elham Tavanai
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Piche-Shemiran, Enghelab Ave, Tehran, Iran
| | - Ghassem Mohammadkhani
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Piche-Shemiran, Enghelab Ave, Tehran, Iran.
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28
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Falah M, Houshmand M, Najafi M, Balali M, Mahmoudian S, Asghari A, Emamdjomeh H, Farhadi M. The potential role for use of mitochondrial DNA copy number as predictive biomarker in presbycusis. Ther Clin Risk Manag 2016; 12:1573-1578. [PMID: 27799778 PMCID: PMC5077262 DOI: 10.2147/tcrm.s117491] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVES Age-related hearing impairment, or presbycusis, is the most common communication disorder and neurodegenerative disease in the elderly. Its prevalence is expected to increase, due to the trend of growth of the elderly population. The current diagnostic test for detection of presbycusis is implemented after there has been a change in hearing sensitivity. Identification of a pre-diagnostic biomarker would raise the possibility of preserving hearing sensitivity before damage occurs. Mitochondrial dysfunction, including the production of reactive oxygen species and induction of expression of apoptotic genes, participates in the progression of presbycusis. Mitochondrial DNA sequence variation has a critical role in presbycusis. However, the nature of the relationship between mitochondrial DNA copy number, an important biomarker in many other diseases, and presbycusis is undetermined. METHODS Fifty-four subjects with presbycusis and 29 healthy controls were selected after ear, nose, throat examination and pure-tone audiometry. DNA was extracted from peripheral blood samples. The copy number of mitochondrial DNA relative to the nuclear genome was measured by quantitative real-time polymerase chain reaction. RESULTS Subjects with presbycusis had a lower median mitochondrial DNA copy number than healthy subjects and the difference was statistically significant (P=0.007). Mitochondrial DNA copy number was also significantly associated with degree of hearing impairment (P=0.025) and audiogram configuration (P=0.022). CONCLUSION The findings of this study suggest that lower mitochondrial DNA copy number is responsible for presbycusis through alteration of mitochondrial function. Moreover, the significant association of mitochondrial DNA copy number in peripheral blood samples with the degree of hearing impairment and audiogram configuration has potential for use as a standard test for presbycusis, providing the possibility of the development of an easy-to-use biomarker for the early detection of this condition.
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Affiliation(s)
- Masoumeh Falah
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran; Cellular and Molecular Research Center, Biochemistry Department, Iran University of Medical Sciences, Tehran, Iran
| | - Massoud Houshmand
- Department of Medical Genetics, National Institute for Genetic Engineering and Biotechnology, Tehran, Iran
| | - Mohammad Najafi
- Cellular and Molecular Research Center, Biochemistry Department, Iran University of Medical Sciences, Tehran, Iran
| | - Maryam Balali
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran
| | - Saeid Mahmoudian
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran
| | - Alimohamad Asghari
- Skull base research center, Iran University of Medical Sciences, Tehran, Iran
| | - Hessamaldin Emamdjomeh
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Farhadi
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran
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Formichi P, Radi E, Branca C, Battisti C, Brunetti J, Da Pozzo P, Giannini F, Dotti MT, Bracci L, Federico A. Oxidative stress-induced apoptosis in peripheral blood lymphocytes from patients with POLG-related disorders. J Neurol Sci 2016; 368:359-68. [PMID: 27538665 DOI: 10.1016/j.jns.2016.07.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 07/07/2016] [Accepted: 07/19/2016] [Indexed: 12/29/2022]
Abstract
BACKGROUND POLG-related disorders are a group of heterogeneous diseases characterized by an overlapping clinical presentations and associated with mutations in the POLG gene. POLG codes for the catalytic subunit of mitochondrial polymerase gamma (POLG), essential for mitochondrial DNA (mtDNA) replication and repair. Studies on mutator POLG mice showed an increase in oxidative stress and apoptosis. In this regard we analysed the involvement of POLG mutations in the apoptotic regulation, evaluating apoptosis in peripheral blood lymphocytes (PBLs) from patients with POLG-related diseases. METHODS Cells were cultured under basal conditions and with 2-deoxy-d-ribose (dRib), a reducing sugar that induces apoptosis by oxidative stress. Apoptosis rate was assessed by flow cytometry. Phosphatidylserine translocation, mitochondrial membrane depolarization and caspase 3 activation were also analysed. RESULTS Our data showed higher percentages of apoptosis after dRib treatment in patients with POLG mutations than in controls, while under basal culture conditions, apoptosis levels were similar in the two groups. CONCLUSIONS Cells with POLG mutations are more sensitive than control cells to oxidative stress-induced apoptosis, confirming that mtDNA mutations may have a role in mitochondrial apoptosis pathway. We also suggest that redox state homeostasis may play a crucial role in phenotypic expression of POLG-related diseases.
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Affiliation(s)
- Patrizia Formichi
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Elena Radi
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Chiara Branca
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Carla Battisti
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Jlenia Brunetti
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Paola Da Pozzo
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Fabio Giannini
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Maria Teresa Dotti
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Luisa Bracci
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Antonio Federico
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy.
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Brosel S, Laub C, Averdam A, Bender A, Elstner M. Molecular aging of the mammalian vestibular system. Ageing Res Rev 2016; 26:72-80. [PMID: 26739358 DOI: 10.1016/j.arr.2015.12.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 12/16/2015] [Accepted: 12/21/2015] [Indexed: 12/18/2022]
Abstract
Dizziness and imbalance frequently affect the elderly and contribute to falls and frailty. In many geriatric patients, clinical testing uncovers a dysfunction of the vestibular system, but no specific etiology can be identified. Neuropathological studies have demonstrated age-related degeneration of peripheral and central vestibular neurons, but the molecular mechanisms are poorly understood. In contrast, recent studies into age-related hearing loss strongly implicate mitochondrial dysfunction, oxidative stress and apoptotic cell death of cochlear hair cells. While some data suggest that analogous biological pathomechanisms may underlie vestibular dysfunction, actual proof is missing. In this review, we summarize the available data on the molecular causes of vestibular dysfunction.
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Affiliation(s)
- Sonja Brosel
- German Center for Vertigo and Balance Disorders, Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich, Germany.
| | - Christoph Laub
- Department of Neurology with Friedrich-Baur-Institute, Klinikum Grosshadern, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich, Germany
| | - Anne Averdam
- Department of Neurology with Friedrich-Baur-Institute, Klinikum Grosshadern, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich, Germany
| | - Andreas Bender
- Department of Neurology, Therapiezentrum Burgau, Kapuzinerstr.34, 89331 Burgau, Germany
| | - Matthias Elstner
- Department of Neurology with Friedrich-Baur-Institute, Klinikum Grosshadern, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich, Germany; Department of Neurology and Clinical Neurophysiology, Academic Hospital Munich-Bogenhausen, Technical University of Munich, Englschalkingerstr. 77, 81925 Munich, Germany
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Du Z, Li S, Liu L, Yang Q, Zhang H, Gao C. NADPH oxidase 3‑associated oxidative stress and caspase 3‑dependent apoptosis in the cochleae of D‑galactose‑induced aged rats. Mol Med Rep 2015; 12:7883-90. [PMID: 26498835 PMCID: PMC4758280 DOI: 10.3892/mmr.2015.4430] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 07/23/2015] [Indexed: 01/27/2023] Open
Abstract
Oxidative damage to mitochondrial DNA (mtDNA) and cell apoptosis are heavily implicated in aging. Our previous study established a mimetic rat model of aging in the cochleae using D‑galactose (D‑gal), and revealed that chronic injection of D‑gal can increase oxidative stress and mtDNA common deletions (CD). The aim of the present study was to investigate the sources of reactive oxygen species and the occurrence of apoptosis in the cochleae of rats following 8 weeks of D‑gal exposure. The results of the present study indicated that an elevated accumulation of the mtDNA CD and mitochondrial ultrastructural damage occurred in the cochleae of rats injected with D‑gal for 8 weeks. In addition, the levels of 8‑hydroxy‑2‑deoxyguanosine, NADPH oxidase (NOX) 3, P22phox and cleaved caspase 3, and the number of terminal deoxynucleotidyl transferase‑mediated deoxyuridine triphosphate nick‑end‑labelling‑positive cells were increased in the cochleae of D‑gal‑treated rats, compared with the controls. These findings suggested that nitric oxide synthase NOX3‑associated oxidative stress may contribute to the accumulation of mtDNA mutations and activate a caspase 3‑dependent apoptotic signalling pathway in the cochleae during aging. The present study also provided novel insights into the development of age‑associated hearing loss, also termed presbycusis.
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Affiliation(s)
- Zhengde Du
- Department of Otorhinolaryngology, Nanshan Affiliated Hospital of Guangdong Medical College, Shenzhen, Guangdong 518052, P.R. China
| | - Shuo Li
- Department of Otorhinolaryngology, Nanshan Affiliated Hospital of Guangdong Medical College, Shenzhen, Guangdong 518052, P.R. China
| | - Lin Liu
- Department of Pharmacology, College of Pharmacy, Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Qiong Yang
- Department of Otorhinolaryngology, Nanshan Affiliated Hospital of Guangdong Medical College, Shenzhen, Guangdong 518052, P.R. China
| | - Hongwei Zhang
- Department of Otorhinolaryngology, Nanshan Affiliated Hospital of Guangdong Medical College, Shenzhen, Guangdong 518052, P.R. China
| | - Chunsheng Gao
- Department of Otorhinolaryngology, Nanshan Affiliated Hospital of Guangdong Medical College, Shenzhen, Guangdong 518052, P.R. China
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Sun HY, Hu YJ, Zhao XY, Zhong Y, Zeng LL, Chen XB, Yuan J, Wu J, Sun Y, Kong W, Kong WJ. Age-related changes in mitochondrial antioxidant enzyme Trx2 and TXNIP-Trx2-ASK1 signal pathways in the auditory cortex of a mimetic aging rat model: changes to Trx2 in the auditory cortex. FEBS J 2015; 282:2758-74. [PMID: 25996168 DOI: 10.1111/febs.13324] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 04/10/2015] [Accepted: 05/18/2015] [Indexed: 12/21/2022]
Abstract
Age-associated degeneration in the central auditory system, which is defined as central presbycusis, can impair sound localization and speech perception. Research has shown that oxidative stress plays a central role in the pathological process of central presbycusis. Thioredoxin 2 (Trx2), one member of thioredoxin family, plays a key role in regulating the homeostasis of cellular reactive oxygen species and anti-apoptosis. The purpose of this study was to explore the association between Trx2 and the phenotype of central presbycusis using a mimetic aging animal model induced by long-term exposure to d-galactose (d-Gal). We also explored changes in thioredoxin-interacting protein (TXNIP), apoptosis signal regulating kinase 1 (ASK1) and phosphorylated ASK1 (p-ASK1) expression, as well as the Trx2-TXNIP/Trx2-ASK1 binding complex in the auditory cortex of mimetic aging rats. Our results demonstrate that, compared with control groups, the levels of Trx2 and Trx2-ASK1 binding complex were significantly reduced, whereas TXNIP, ASK1 p-ASK1 expression, and Trx2-TXNIP binding complex were significantly increased in the auditory cortex of the mimetic aging groups. Our results indicated that changes in Trx2 and the TXNIP-Trx2-ASK1 signal pathway may participate in the pathogenesis of central presbycusis.
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Affiliation(s)
- Hai-Ying Sun
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
| | - Yu-Juan Hu
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
| | - Xue-Yan Zhao
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Zhong
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
| | - Ling-Ling Zeng
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
| | - Xu-Bo Chen
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
| | - Jie Yuan
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Wu
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
| | - Yu Sun
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
| | - Wen Kong
- Department of Endocrinology, Huazhong University of Science and Technology, Wuhan, China
| | - Wei-Jia Kong
- Department of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China.,Key Laboratory of Neurological Disease, Ministry of Education, Wuhan, China
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Yang L, Zhang H, Han X, Zhao X, Hu F, Li P, Xie G, Gao L, Cheng L, Song X, Han F. Attenuation of hearing loss in DBA/2J mice by anti-apoptotic treatment. Hear Res 2015; 327:109-16. [PMID: 26003529 DOI: 10.1016/j.heares.2015.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 04/11/2015] [Accepted: 05/08/2015] [Indexed: 01/07/2023]
Abstract
DBA/2J mice are characterized by early onset hearing loss at about 3-4 weeks of age. Mutations in cadherin 23 (Cdh23) and fascin-2 (Fscn2) are responsible for the phenotypes, but the underlying mechanism is unknown. In the present study, DBA/2J mice displayed progressive hair cell loss and degeneration of spiral ganglion neurons (SGNs) after 2 weeks of age; however, the mRNA level of Caspase-3 in the inner ears was much higher at 2 weeks of age than that at 4 or 8 weeks of age. Moreover, transcriptional levels of Caspase-3 and Caspase-9 in the inner ears of DBA/2J mice were significantly higher than those of C57BL/6J mice at 2 or 8 weeks of age. Immunohistochemistry localized Caspase-3 and Caspase-9 mainly to the hair cells, SGNs and stria vascularis of the cochleae. To determine the significance of caspase-dependent apoptosis in the hearing loss, the pan-caspase inhibitor Z-VAD-FMK was given intraperitoneally to DBA/J2 mice over an 8-week period starting at one week of age. Blockage of caspases preserved hearing in the mice by more than 10 dB (dB) sound pressure level (SPL) of the ABR thresholds and significantly reduced outer hair cell loss at the basal turns of the cochleae. These results demonstrate that apoptosis in the cochleae of DBA/J2 mice contributes to the early onset of hearing loss, which can be attenuated by anti-apoptotic treatment.
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Affiliation(s)
- Linlin Yang
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Department of Otorhinolaryngology-Head and Neck Surgery, Yuhuangding Hospital, 20 East Yuhuangding Road, Yantai 264000, Shandong, PR China
| | - Heng Zhang
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Transformative Otology and Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
| | - Xu Han
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Transformative Otology and Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
| | - Xin Zhao
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Transformative Otology and Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
| | - Fangyuan Hu
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Transformative Otology and Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
| | - Ping Li
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Transformative Otology and Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
| | - Gang Xie
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Transformative Otology and Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
| | - Lixiang Gao
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Transformative Otology and Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
| | - Lin Cheng
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Transformative Otology and Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
| | - Xicheng Song
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Department of Otorhinolaryngology-Head and Neck Surgery, Yuhuangding Hospital, 20 East Yuhuangding Road, Yantai 264000, Shandong, PR China.
| | - Fengchan Han
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China; Transformative Otology and Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China.
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NADPH oxidase 2-dependent oxidative stress, mitochondrial damage and apoptosis in the ventral cochlear nucleus of d-galactose-induced aging rats. Neuroscience 2015; 286:281-92. [DOI: 10.1016/j.neuroscience.2014.11.061] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 11/20/2014] [Accepted: 11/20/2014] [Indexed: 01/11/2023]
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Gurkar AU, Niedernhofer LJ. Comparison of mice with accelerated aging caused by distinct mechanisms. Exp Gerontol 2015; 68:43-50. [PMID: 25617508 DOI: 10.1016/j.exger.2015.01.045] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/17/2015] [Accepted: 01/20/2015] [Indexed: 02/05/2023]
Abstract
Aging is the primary risk factor for numerous chronic, debilitating diseases. These diseases impact quality of life of the elderly and consume a large portion of health care costs. The cost of age-related diseases will only increase as the world's population continues to live longer. Thus it would be advantageous to consider aging itself as a therapeutic target, potentially stemming multiple age-related diseases simultaneously. While logical, this is extremely challenging as the molecular mechanisms that drive aging are still unknown. Furthermore, clinical trials to treat aging are impractical. Even in preclinical models, testing interventions to extend healthspan in old age are lengthy and therefore costly. One approach to expedite aging studies is to take advantage of mouse strains that are engineered to age rapidly. These strains are genetically and phenotypically quite diverse. This review aims to offer a comparison of several of these strains to highlight their relative strengths and weaknesses as models of mammalian and more specifically human aging. Additionally, careful identification of commonalities among the strains may lead to the identification of fundamental pathways of aging.
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Affiliation(s)
- Aditi U Gurkar
- Department of Metabolism and Aging, Scripps Florida, 130 Scripps Way #3B3, Jupiter, FL 33458, USA
| | - Laura J Niedernhofer
- Department of Metabolism and Aging, Scripps Florida, 130 Scripps Way #3B3, Jupiter, FL 33458, USA.
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Bowl MR, Dawson SJ. The mouse as a model for age-related hearing loss - a mini-review. Gerontology 2014; 61:149-57. [PMID: 25471225 DOI: 10.1159/000368399] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 09/17/2014] [Indexed: 11/19/2022] Open
Abstract
The most common form of sensory disability is age-related hearing loss (ARHL), also referred to as presbycusis. ARHL is a complex disorder with a mixture of genetic and environmental components, a combination that leads to a progressive decline in hearing function with increased age. In the last 15 years, there has been a vast increase in our knowledge of the genes that underlie congenital deafness and the critical components of hearing. In contrast, knowledge of the pathological processes involved in ARHL remains very limited. The mouse has proved an essential tool in the identification of early-onset deafness genes and in revealing the basic mechanisms of hearing. As focus is now turning toward elucidating the most common form of hearing loss, ARHL, the mouse will again play a fundamental role in this research. Here, we review the need for an animal model and discuss the suitability of the mouse as an ARHL model. Finally, we outline the ways in which hearing researchers are utilising the mouse in the investigation of ARHL and provide perspectives on the need for these data to be integrated with the results of human genetic studies.
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Affiliation(s)
- Michael R Bowl
- Mammalian Genetics Unit, MRC Harwell, Harwell Oxford, UK
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Fujimoto C, Yamasoba T. Oxidative stresses and mitochondrial dysfunction in age-related hearing loss. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:582849. [PMID: 25110550 PMCID: PMC4106174 DOI: 10.1155/2014/582849] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 06/24/2014] [Accepted: 06/24/2014] [Indexed: 11/18/2022]
Abstract
Age-related hearing loss (ARHL), the progressive loss of hearing associated with aging, is the most common sensory disorder in the elderly population. The pathology of ARHL includes the hair cells of the organ of Corti, stria vascularis, and afferent spiral ganglion neurons as well as the central auditory pathways. Many studies have suggested that the accumulation of mitochondrial DNA damage, the production of reactive oxygen species, and decreased antioxidant function are associated with subsequent cochlear senescence in response to aging stress. Mitochondria play a crucial role in the induction of intrinsic apoptosis in cochlear cells. ARHL can be prevented in laboratory animals by certain interventions, such as caloric restriction and supplementation with antioxidants. In this review, we will focus on previous research concerning the role of the oxidative stress and mitochondrial dysfunction in the pathology of ARHL in both animal models and humans and introduce concepts that have recently emerged regarding the mechanisms of the development of ARHL.
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Affiliation(s)
- Chisato Fujimoto
- Department of Otolaryngology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Tatsuya Yamasoba
- Department of Otolaryngology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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38
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Integrative analysis of independent transcriptome data for rare diseases. Methods 2014; 69:315-25. [PMID: 24981076 DOI: 10.1016/j.ymeth.2014.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 06/12/2014] [Accepted: 06/15/2014] [Indexed: 01/12/2023] Open
Abstract
High-throughput technologies used to interrogate transcriptomes have been generating a great amount of publicly available gene expression data. For rare diseases that lack of clinical samples and research funding, there is a practical benefit to jointly analyze existing data sets commonly related to a specific rare disease. In this study, we collected a number of independently generated transcriptome data sets from four species: human, fly, mouse and worm. All data sets included samples with both normal and abnormal mitochondrial function. We reprocessed each data set to standardize format, scale and gene annotation and used HomoloGene database to map genes between species. Standardized procedure was also applied to compare gene expression profiles of normal and abnormal mitochondrial function to identify differentially expressed genes. We further used meta-analysis and other integrative analyses to recognize patterns across data sets and species. Novel insights related to mitochondrial dysfunction was revealed via these analyses, such as a group of genes consistently dysregulated by impaired mitochondrial function in multiple species. This study created a template for the study of rare diseases using genomic technologies and advanced statistical methods. All data and results generated by this study are freely available and stored at http://goo.gl/nOGWC2, to support further data mining.
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Iwasaki S, Yamasoba T. Dizziness and Imbalance in the Elderly: Age-related Decline in the Vestibular System. Aging Dis 2014; 6:38-47. [PMID: 25657851 DOI: 10.14336/ad.2014.0128] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/27/2014] [Accepted: 01/28/2014] [Indexed: 01/30/2023] Open
Abstract
Dizziness and imbalance are amongst the most common complaints in older people, and are a growing public health concern since they put older people at a significantly higher risk of falling. Although the causes of dizziness in older people are multifactorial, peripheral vestibular dysfunction is one of the most frequent causes. Benign paroxysmal positional vertigo is the most frequent form of vestibular dysfunction in the elderly, followed by Meniere's disease. Every factor associated with the maintenance of postural stability deteriorates during aging. Age-related deterioration of peripheral vestibular function has been demonstrated through quantitative measurements of the vestibulo-ocular reflex with rotational testing and of the vestibulo-collic reflex with testing of vestibular evoked myogenic potentials. Age-related decline of vestibular function has been shown to correlate with the age-related decrease in the number of vestibular hair cells and neurons. The mechanism of age-related cellular loss in the vestibular endorgan is unclear, but it is thought that genetic predisposition and cumulative effect of oxidative stress may both play an important role. Since the causes of dizziness in older people are multi-factorial, management of this disease should be customized according to the etiologies of each individual. Vestibular rehabilitation is found to be effective in treating both unilateral and bilateral vestibular dysfunction. Various prosthetic devices have also been developed to improve postural balance in older people. Although there have been no medical treatments improving age-related vestibular dysfunction, new medical treatments such as mitochondrial antioxidants or caloric restriction, which have been effective in preventing age-related hearing loss, should be ienvestigated in the future.
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Affiliation(s)
- Shinichi Iwasaki
- Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Tatsuya Yamasoba
- Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan
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Takada Y, Beyer LA, Swiderski DL, O'Neal AL, Prieskorn DM, Shivatzki S, Avraham KB, Raphael Y. Connexin 26 null mice exhibit spiral ganglion degeneration that can be blocked by BDNF gene therapy. Hear Res 2013; 309:124-35. [PMID: 24333301 DOI: 10.1016/j.heares.2013.11.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 11/16/2013] [Accepted: 11/19/2013] [Indexed: 01/11/2023]
Abstract
Mutations in the connexin 26 gene (GJB2) are the most common genetic cause of deafness, leading to congenital bilateral non-syndromic sensorineural hearing loss. Here we report the generation of a mouse model for a connexin 26 (Cx26) mutation, in which cre-Sox10 drives excision of the Cx26 gene from non-sensory cells flanking the auditory epithelium. We determined that these conditional knockout mice, designated Gjb2-CKO, have a severe hearing loss. Immunocytochemistry of the auditory epithelium confirmed absence of Cx26 in the non-sensory cells. Histology of the organ of Corti and the spiral ganglion neurons (SGNs) performed at ages 1, 3, or 6 months revealed that in Gjb2-CKO mice, the organ of Corti began to degenerate in the basal cochlear turn at an early stage, and the degeneration rapidly spread to the apex. In addition, the density of SGNs in Rosenthal's canal decreased rapidly along a gradient from the base of the cochlea to the apex, where some SGNs survived until at least 6 months of age. Surviving neurons often clustered together and formed clumps of cells in the canal. We then assessed the influence of brain derived neurotrophic factor (BDNF) gene therapy on the SGNs of Gjb2-CKO mice by inoculating Adenovirus with the BDNF gene insert (Ad.BDNF) into the base of the cochlea via the scala tympani or scala media. We determined that over-expression of BDNF beginning around 1 month of age resulted in a significant rescue of neurons in Rosenthal's canal of the cochlear basal turn but not in the middle or apical portions. This data may be used to design therapies for enhancing the SGN physiological status in all GJB2 patients and especially in a sub-group of GJB2 patients where the hearing loss progresses due to ongoing degeneration of the auditory nerve, thereby improving the outcome of cochlear implant therapy in these ears.
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Affiliation(s)
- Yohei Takada
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA; Department of Otolaryngology, Kansai Medical University, 2-3-1, Shinmachi, Hirakata, Osaka 573-1191, Japan
| | - Lisa A Beyer
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA
| | - Donald L Swiderski
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA
| | - Aubrey L O'Neal
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA
| | - Diane M Prieskorn
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA
| | - Shaked Shivatzki
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yehoash Raphael
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA.
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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: 359] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [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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42
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Ruan Q, Ma C, Zhang R, Yu Z. Current status of auditory aging and anti-aging research. Geriatr Gerontol Int 2013; 14:40-53. [PMID: 23992133 DOI: 10.1111/ggi.12124] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2013] [Indexed: 01/08/2023]
Affiliation(s)
- Qingwei Ruan
- Central Lab; Shanghai Institute of Geriatrics and Gerontology; Huadong Hospital, Shanghai Medical College, Fudan University; Shanghai China
| | - Cheng Ma
- Central Lab; Shanghai Institute of Geriatrics and Gerontology; Huadong Hospital, Shanghai Medical College, Fudan University; Shanghai China
| | - Ruxin Zhang
- Central Lab; Shanghai Institute of Geriatrics and Gerontology; Huadong Hospital, Shanghai Medical College, Fudan University; Shanghai China
| | - Zhuowei Yu
- Central Lab; Shanghai Institute of Geriatrics and Gerontology; Huadong Hospital, Shanghai Medical College, Fudan University; Shanghai China
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43
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Han C, Someya S. Mouse models of age-related mitochondrial neurosensory hearing loss. Mol Cell Neurosci 2013; 55:95-100. [PMID: 22820179 PMCID: PMC3609944 DOI: 10.1016/j.mcn.2012.07.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/01/2012] [Accepted: 07/10/2012] [Indexed: 11/18/2022] Open
Abstract
Hearing loss is the most common sensory disorder in the elderly population. Overall, 10% of the population has a hearing loss in the US, and this age-related hearing disorder is projected to afflict more than 28 million Americans by 2030. Age-related hearing loss is associated with loss of sensory hair cells (sensory hearing loss) and/or spiral ganglion neurons (neuronal hearing loss) in the cochlea of the inner ear. Many lines of evidence indicate that oxidative stress and associated mitochondrial dysfunction play a central role in age-related neurodegenerative diseases and are a cause of age-related neurosensory hearing loss. Yet, the molecular mechanisms of how oxidative stress and/or mitochondrial dysfunction lead to hearing loss during aging remain unclear, and currently there is no treatment for this age-dependent disorder. Several mouse models of aging and age-related diseases have been linked to age-related mitochondrial neurosensory hearing loss. Evaluation of these animal models has offered basic knowledge of the mechanism underlying hearing loss associated with oxidative stress, mitochondrial dysfunction, and aging. Here we review the evidence that specific mutations in the mitochondrial DNA or nuclear DNA that affect mitochondrial function result in increased oxidative damage and associated loss of sensory hair cells and/or spiral ganglion neurons in the cochlea during aging, thereby causing hearing loss in these mouse models. Future studies comparing these models will provide further insight into fundamental knowledge about the disordered process of hearing and treatments to improve the lives of individuals with communication disorders. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
- Chul Han
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL 32610, USA
| | - Shinichi Someya
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL 32610, USA
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Age-related hearing loss in Mn-SOD heterozygous knockout mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:325702. [PMID: 23936608 PMCID: PMC3710654 DOI: 10.1155/2013/325702] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 06/02/2013] [Indexed: 01/07/2023]
Abstract
Age-related hearing loss (AHL) reduces the quality of life for many elderly individuals. Manganese superoxide dismutase (Mn-SOD), one of the antioxidant enzymes acting within the mitochondria, plays a crucial role in scavenging reactive oxygen species (ROS). To determine whether reduction in Mn-SOD accelerates AHL, we evaluated auditory function in Mn-SOD heterozygous knockout (HET) mice and their littermate wild-type (WT) C57BL/6 mice by means of auditory brainstem response (ABR). Mean ABR thresholds were significantly increased at 16 months when compared to those at 4 months in both WT and HET mice, but they did not significantly differ between them at either age. The extent of hair cell loss, spiral ganglion cell density, and thickness of the stria vascularis also did not differ between WT and HET mice at either age. At 16 months, immunoreactivity of 8-hydroxydeoxyguanosine was significantly greater in the SGC and SV in HET mice compared to WT mice, but that of 4-hydroxynonenal did not differ between them. These findings suggest that, although decrease of Mn-SOD by half may increase oxidative stress in the cochlea to some extent, it may not be sufficient to accelerate age-related cochlear damage under physiological aging process.
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45
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Pierce S, Gersak K, Michaelson-Cohen R, Walsh T, Lee M, Malach D, Klevit R, King MC, Levy-Lahad E. Mutations in LARS2, encoding mitochondrial leucyl-tRNA synthetase, lead to premature ovarian failure and hearing loss in Perrault syndrome. Am J Hum Genet 2013; 92:614-20. [PMID: 23541342 DOI: 10.1016/j.ajhg.2013.03.007] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 02/25/2013] [Accepted: 03/11/2013] [Indexed: 11/25/2022] Open
Abstract
The genetic causes of premature ovarian failure (POF) are highly heterogeneous, and causative mutations have been identified in more than ten genes so far. In two families affected by POF accompanied by hearing loss (together, these symptoms compose Perrault syndrome), exome sequencing revealed mutations in LARS2, encoding mitochondrial leucyl-tRNA synthetase: homozygous c.1565C>A (p.Thr522Asn) in a consanguineous Palestinian family and compound heterozygous c.1077delT and c.1886C>T (p.Thr629Met) in a nonconsanguineous Slovenian family. LARS2 c.1077delT leads to a frameshift at codon 360 of the 901 residue protein. LARS2 p.Thr522Asn occurs in the LARS2 catalytic domain at a site conserved from bacteria through mammals. LARS2 p.Thr629Met occurs in the LARS2 leucine-specific domain, which is adjacent to a catalytic loop critical in all species but for which primary sequence is not well conserved. A recently developed method of detecting remote homologies revealed threonine at this site in consensus sequences derived from multiple-species alignments seeded by human and E. coli residues at this region. Yeast complementation indicated that LARS2 c.1077delT is nonfunctional and that LARS2 p.Thr522Asn is partially functional. LARS2 p.Thr629Met was functional in this assay but might be insufficient as a heterozygote with the fully nonfunctional LARS2 c.1077delT allele. A known C. elegans strain with the protein-truncating alteration LARS-2 p.Trp247Ter was confirmed to be sterile. After HARS2, LARS2 is the second gene encoding mitochondrial tRNA synthetase to be found to harbor mutations leading to Perrault syndrome, further supporting a critical role for mitochondria in the maintenance of ovarian function and hearing.
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Lu J, Huang Y, Wang Y, Li Y, Zhang Y, Wu J, Zhao F, Meng S, Yu X, Ma Q, Song M, Chang N, Bittles AH, Wang W. Profiling plasma peptides for the identification of potential ageing biomarkers in Chinese Han adults. PLoS One 2012; 7:e39726. [PMID: 22802942 PMCID: PMC3389038 DOI: 10.1371/journal.pone.0039726] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 05/25/2012] [Indexed: 12/12/2022] Open
Abstract
Advancing age is associated with cardiovascular disease, diabetes mellitus and cancer, and shows significant inter-individual variability. To identify ageing-related biomarkers we performed a proteomic analysis on 1890 Chinese Han individuals, 1136 males and 754 females, aged 18 to 82 years, using weak cation exchange magnetic bead based MALDI-TOF-MS analysis. The study identified 44 peptides which varied in concentration in different age groups. In particular, apolipoprotein A-I (ApoA1) concentration gradually increased between 18 to 50 years of age, the levels of fibrinogen alpha (FGA) decreased over the same age span, while albumin (ALB) was significantly degraded in middle-aged individuals. In addition, the plasma peptide profiles of FGA and four other unidentified proteins were found to be gender-dependent. Plasma proteins such as FGA, ALB and ApoA1 are significantly correlated with age in the Chinese Han population and could be employed as indicative ageing-related biomarkers.
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Affiliation(s)
- Jiapeng Lu
- School of Public Health and Family Medicine, Capital Medical University, Beijing, People’s Republic of China
- Municipal Key Laboratory of Clinical Epidemiology, Beijing, People’s Republic of China
| | - Yuqing Huang
- Department of Chest Surgery, Beijing Haidian Hospital, Beijing, People’s Republic of China
| | - Youxin Wang
- School of Public Health and Family Medicine, Capital Medical University, Beijing, People’s Republic of China
- Municipal Key Laboratory of Clinical Epidemiology, Beijing, People’s Republic of China
| | - Yan Li
- Bioyong Technologies Inc, Beijing, People’s Republic of China
| | - Yujun Zhang
- Bioyong Technologies Inc, Beijing, People’s Republic of China
| | - Jingjing Wu
- School of Public Health and Family Medicine, Capital Medical University, Beijing, People’s Republic of China
- Municipal Key Laboratory of Clinical Epidemiology, Beijing, People’s Republic of China
| | - Feifei Zhao
- School of Public Health and Family Medicine, Capital Medical University, Beijing, People’s Republic of China
- Municipal Key Laboratory of Clinical Epidemiology, Beijing, People’s Republic of China
| | - Shijiao Meng
- School of Public Health and Family Medicine, Capital Medical University, Beijing, People’s Republic of China
- Municipal Key Laboratory of Clinical Epidemiology, Beijing, People’s Republic of China
| | - Xinwei Yu
- School of Public Health and Family Medicine, Capital Medical University, Beijing, People’s Republic of China
- Municipal Key Laboratory of Clinical Epidemiology, Beijing, People’s Republic of China
| | - Qingwei Ma
- Bioyong Technologies Inc, Beijing, People’s Republic of China
| | - Manshu Song
- School of Public Health and Family Medicine, Capital Medical University, Beijing, People’s Republic of China
- Municipal Key Laboratory of Clinical Epidemiology, Beijing, People’s Republic of China
- * E-mail: (MS); (NC); (WW)
| | - Naibai Chang
- Department of Hematology, Beijing Hospital, Beijing, People’s Republic of China
- * E-mail: (MS); (NC); (WW)
| | - Alan H. Bittles
- School of Medical Sciences, Edith Cowan University, Perth, Australia
- Centre for Comparative Genomics, Murdoch University, Perth, Australia
| | - Wei Wang
- School of Public Health and Family Medicine, Capital Medical University, Beijing, People’s Republic of China
- College of Life Sciences, Graduate University of Chinese Academy of Sciences, Beijing, People’s Republic of China
- School of Medical Sciences, Edith Cowan University, Perth, Australia
- Municipal Key Laboratory of Clinical Epidemiology, Beijing, People’s Republic of China
- * E-mail: (MS); (NC); (WW)
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Kidd Iii AR, Bao J. Recent advances in the study of age-related hearing loss: a mini-review. Gerontology 2012; 58:490-6. [PMID: 22710288 PMCID: PMC3766364 DOI: 10.1159/000338588] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 04/02/2012] [Indexed: 11/19/2022] Open
Abstract
Hearing loss is a common age-associated affliction that can result from the loss of hair cells and spiral ganglion neurons (SGNs) in the cochlea. Although hair cells and SGNs are typically lost in the same cochlea, recent analysis suggests that they can occur independently, via unique mechanisms. Research has identified both environmental and genetic factors that contribute to degeneration of cochlear cells. Additionally, molecular analysis has identified multiple cell-signaling mechanisms that likely contribute to pathological changes that result in hearing deficiencies. These analyses should serve as useful primers for future work, including genomic and proteomic analysis, to elucidate the mechanisms driving cell loss in the aging cochlea. Significant progress in this field has occurred in the past decade. As our understanding of aging-induced cochlear changes continues to improve, our ability to offer medical intervention will surely benefit the growing elderly population.
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Affiliation(s)
- Ambrose R Kidd Iii
- Department of Otolaryngology, Center for Aging, Washington University School of Medicine, St. Louis, Mo., USA
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Fox RG, Magness S, Kujoth GC, Prolla TA, Maeda N. Mitochondrial DNA polymerase editing mutation, PolgD257A, disturbs stem-progenitor cell cycling in the small intestine and restricts excess fat absorption. Am J Physiol Gastrointest Liver Physiol 2012; 302:G914-24. [PMID: 22345551 PMCID: PMC3362078 DOI: 10.1152/ajpgi.00402.2011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Changes in intestinal absorption of nutrients are important aspects of the aging process. To address this issue, we investigated the impact of accelerated mitochondrial DNA mutations on the stem/progenitor cells in the crypts of Lieberkühn in mice homozygous for a mitochondrial DNA polymerase gamma mutation, Polg(D257A), that exhibit accelerated aging phenotype. As early as 3-7 mo of age, the small intestine was significantly enlarged in the PolgD257A mice. The crypts of the PolgD257A mice contained 20% more cells than those of their wild-type littermates and exhibited a 10-fold increase in cellular apoptosis primarily in the stem/progenitor cell zones. Actively dividing cells were proportionally increased, yet a significantly smaller proportion of cells was in the S phase of the cell cycle. Stem cell-derived organoids from PolgD257A mice failed to develop fully in culture and exhibited fewer crypt units, indicating an impact of the mutation on the intestinal epithelial stem/progenitor cell maintenance. In addition, epithelial cell migration along the crypt-villus axis was slowed and less organized, and the ATP content in the villi was significantly reduced. On a high-fat, high-carbohydrate diet, PolgD257A mice showed significantly restricted absorption of excess lipids accompanied by an increase in fecal steatocrits. We conclude that the PolgD257A mutation causes cell cycle dysregulation in the crypts leading to the age-associated changes in the morphology of the small intestine and contributes to the restricted absorption of dietary lipids.
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Affiliation(s)
- Raymond G. Fox
- 1Curriculum in Genetics and Molecular Biology, ,2Department of Pathology and Laboratory Medicine,
| | - Scott Magness
- 3Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, North Carolina; and
| | - Gregory C. Kujoth
- Departments of 4Genetics and Medical Genetics and ,5Neurological Surgery, University of Wisconsin, Madison, Wisconsin
| | | | - Nobuyo Maeda
- 1Curriculum in Genetics and Molecular Biology, ,2Department of Pathology and Laboratory Medicine,
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Raimundo N, Song L, Shutt TE, McKay SE, Cotney J, Guan MX, Gilliland TC, Hohuan D, Santos-Sacchi J, Shadel GS. Mitochondrial stress engages E2F1 apoptotic signaling to cause deafness. Cell 2012; 148:716-26. [PMID: 22341444 DOI: 10.1016/j.cell.2011.12.027] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 10/31/2011] [Accepted: 12/15/2011] [Indexed: 01/03/2023]
Abstract
Mitochondrial dysfunction causes poorly understood tissue-specific pathology stemming from primary defects in respiration, coupled with altered reactive oxygen species (ROS), metabolic signaling, and apoptosis. The A1555G mtDNA mutation that causes maternally inherited deafness disrupts mitochondrial ribosome function, in part, via increased methylation of the mitochondrial 12S rRNA by the methyltransferase mtTFB1. In patient-derived A1555G cells, we show that 12S rRNA hypermethylation causes ROS-dependent activation of AMP kinase and the proapoptotic nuclear transcription factor E2F1. This retrograde mitochondrial-stress relay is operative in vivo, as transgenic-mtTFB1 mice exhibit enhanced 12S rRNA methylation in multiple tissues, increased E2F1 and apoptosis in the stria vascularis and spiral ganglion neurons of the inner ear, and progressive E2F1-dependent hearing loss. This mouse mitochondrial disease model provides a robust platform for deciphering the complex tissue specificity of human mitochondrial-based disorders, as well as the precise pathogenic mechanism of maternally inherited deafness and its exacerbation by environmental factors.
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Affiliation(s)
- Nuno Raimundo
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
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Osumi Y, Shibata SB, Kanda S, Yagi M, Ooka H, Shimano T, Asako M, Kawamoto K, Kuriyama H, Inoue T, Nishiyama T, Yamashita T, Tomoda K. Downregulation of N-methyl-D-aspartate receptor ζ1 subunit (GluN1) gene in inferior colliculus with aging. Brain Res 2012; 1454:23-32. [PMID: 22483791 DOI: 10.1016/j.brainres.2012.03.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 02/17/2012] [Accepted: 03/06/2012] [Indexed: 11/15/2022]
Abstract
Presbycusis is the impairment of auditory function associated with aging, which stems from peripheral cochlear lesions and degeneration of the central auditory process. The effect of age-induced peripheral hearing loss on the central auditory process is not fully understood. C57Bl/6 (C57) mice present accelerated peripheral hearing loss, which is well developed by middle-age and mimics the human presbycusis pattern. The aim of this study was to elucidate the molecular effects of peripheral hearing loss in the inferior colliculus (IC) with age between young and middle-aged C57 mice using cDNA microarray. Glutamate receptor ionotropic NMDA ζ1 (GluN1) exhibited the greatest decrease in the middle-aged group as determined using cDNA microarray and by further assessment using real-time PCR (qPCR). Histological assessment with in situ hybridization of GluN1 showed significantly decreased expression in all IC subdivisions of the middle-aged group. GluN1 is a receptor for excitatory neurotransmission, and significant downregulation of this gene may be subsequent to the decline of afferent input from the cochlea in aging C57 mice. Consequently, using the combination of microarray, qPCR, and in situ hybridization, we showed that the decline of GluN1 in the IC of aging animals might have a key role in the pathogenesis of presbycusis.
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Affiliation(s)
- Yasunori Osumi
- Department of Otolaryngology, Kansai Medical University, Takii Hospital, 10-15 Fumizono-cho, Moriguchi, Osaka 570-8506, Japan
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