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Ege T, Tao L, North BJ. The Role of Molecular and Cellular Aging Pathways on Age-Related Hearing Loss. Int J Mol Sci 2024; 25:9705. [PMID: 39273652 PMCID: PMC11396656 DOI: 10.3390/ijms25179705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2024] [Revised: 08/27/2024] [Accepted: 09/06/2024] [Indexed: 09/15/2024] Open
Abstract
Aging, a complex process marked by molecular and cellular changes, inevitably influences tissue and organ homeostasis and leads to an increased onset or progression of many chronic diseases and conditions, one of which is age-related hearing loss (ARHL). ARHL, known as presbycusis, is characterized by the gradual and irreversible decline in auditory sensitivity, accompanied by the loss of auditory sensory cells and neurons, and the decline in auditory processing abilities associated with aging. The extended human lifespan achieved by modern medicine simultaneously exposes a rising prevalence of age-related conditions, with ARHL being one of the most significant. While our understanding of the molecular basis for aging has increased over the past three decades, a further understanding of the interrelationship between the key pathways controlling the aging process and the development of ARHL is needed to identify novel targets for the treatment of AHRL. The dysregulation of molecular pathways (AMPK, mTOR, insulin/IGF-1, and sirtuins) and cellular pathways (senescence, autophagy, and oxidative stress) have been shown to contribute to ARHL. However, the mechanistic basis for these pathways in the initiation and progression of ARHL needs to be clarified. Therefore, understanding how longevity pathways are associated with ARHL will directly influence the development of therapeutic strategies to treat or prevent ARHL. This review explores our current understanding of the molecular and cellular mechanisms of aging and hearing loss and their potential to provide new approaches for early diagnosis, prevention, and treatment of ARHL.
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Affiliation(s)
- Tuba Ege
- Biomedical Sciences Department, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Litao Tao
- Biomedical Sciences Department, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Brian J North
- Biomedical Sciences Department, School of Medicine, Creighton University, Omaha, NE 68178, USA
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Wu W, Chen P, Yang J, Liu Y. A Low Dose of Rapamycin Promotes Hair Cell Differentiation by Enriching SOX2 + Progenitors in the Neonatal Mouse Inner Ear Organoids. J Assoc Res Otolaryngol 2024; 25:149-165. [PMID: 38472516 PMCID: PMC11018585 DOI: 10.1007/s10162-024-00938-1] [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: 01/01/2023] [Accepted: 02/15/2024] [Indexed: 03/14/2024] Open
Abstract
PURPOSE To investigate the impact of rapamycin on the differentiation of hair cells. METHODS Murine cochlear organoids were derived from cochlear progenitor cells. Different concentrations of rapamycin were added into the culture medium at different proliferation and differentiation stages. RESULTS Rapamycin exhibited a concentration-dependent reduction in the proliferation of these inner ear organoids. Nevertheless, organoids subjected to a 10-nM dose of rapamycin demonstrated a markedly increased proportion of hair cells. Furthermore, rapamycin significantly upregulated the expression of markers associated with both hair cells and supporting cells, including ATOH1, MYO7A, and SOX2. Mechanistic studies revealed that rapamycin preferentially suppressed cells without Sox2 expression during the initial proliferation stage, thereby augmenting and refining the population of SOX2+ progenitors. These enriched progenitors were predisposed to differentiate into hair cells during the later stages of organoid development. Conversely, the use of the mTOR activator MHY 1485 demonstrated opposing effects. CONCLUSION Our findings underscore a practical strategy for enhancing the generation of inner ear organoids with a low dose of rapamycin, achieved by enriching SOX2+ progenitors in an in vitro setting.
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Affiliation(s)
- Wenjin Wu
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Penghui Chen
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Jun Yang
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Yupeng Liu
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
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Zhang X, Cao R, Li C, Zhao H, Zhang R, Che J, Xie J, Tang N, Wang Y, Liu X, Zheng Q. Caffeine Ameliorates Age-Related Hearing Loss by Downregulating the Inflammatory Pathway in Mice. Otol Neurotol 2024; 45:227-237. [PMID: 38320571 PMCID: PMC10922330 DOI: 10.1097/mao.0000000000004098] [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] [Indexed: 02/08/2024]
Abstract
OBJECTIVE Age-related hearing loss (ARHL), also known as presbycusis, is a debilitating sensory impairment that affects the elderly population. There is currently no ideal treatment for ARHL. Long-term caffeine intake was reported to have anti-aging effects in many diseases. This study is to identify whether caffeine could ameliorate ARHL in mice and analyze its mechanism. METHODS Caffeine was administered in drinking water to C57BL/6J mice from the age of 3 months to 12 months. The body weight, food intake and water intake of the mice were monitored during the experiment. The metabolic indicators of serum were detected by ELISA. The function of the hearing system was evaluated by ABR and hematoxylin and eosin staining of the cochlea. Genes' expression were detected by Q-PCR, immunofluorescencee and Western blot. RESULTS The results showed that the ARHL mice exhibited impaired hearing and cochlear tissue compared with the young mice. However, the caffeine-treated ARHL mice showed improved hearing and cochlear tissue morphology. The expression of inflammation-related genes, such as TLR4, Myd88, NF-κB, and IL-1β, was significantly increased in the cochleae of ARHL mice compared with young mice but was down-regulated in the caffeine-treated cochleae. CONCLUSIONS Inflammation is involved in ARHL of mice, and long-term caffeine supplementation could ameliorate ARHL through the down-regulation of the TLR4/NF-κB inflammation pathway. Our findings provide a new idea for preventing ARHL and suggest new drug targets for ARHL treatment.
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Affiliation(s)
- Xiaolin Zhang
- Department of Otolaryngology/Head and Neck Surgery, Institute of Otolaryngology, Binzhou Medical University Hospital, Binzhou, China
| | - Ruijuan Cao
- Department of Otolaryngology/Head and Neck Surgery, Institute of Otolaryngology, Binzhou Medical University Hospital, Binzhou, China
| | - Changye Li
- Department of Otolaryngology/Head and Neck Surgery, Institute of Otolaryngology, Binzhou Medical University Hospital, Binzhou, China
| | - Hongchun Zhao
- Department of Otolaryngology/Head and Neck Surgery, Institute of Otolaryngology, Binzhou Medical University Hospital, Binzhou, China
| | - Ruyi Zhang
- Department of Otolaryngology/Head and Neck Surgery, Institute of Otolaryngology, Binzhou Medical University Hospital, Binzhou, China
| | - Juan Che
- Department of Otolaryngology/Head and Neck Surgery, Institute of Otolaryngology, Binzhou Medical University Hospital, Binzhou, China
| | - Jinwen Xie
- Shandong Binzhou Animal science and veterinary Medicine Academy, Binzhou, China, 256600
| | - Na Tang
- Shandong Binzhou Animal science and veterinary Medicine Academy, Binzhou, China, 256600
| | - Yanfei Wang
- Department of Otolaryngology/Head and Neck Surgery, Institute of Otolaryngology, Binzhou Medical University Hospital, Binzhou, China
| | - Xiuzhen Liu
- Department of Clinical Laboratory, Binzhou Medical University Hospital, Binzhou, China
| | - Qingyin Zheng
- Department of Otolaryngology-HNS, Case Western Reserve University
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Tavanai E, Rahimi V, Khalili ME, Falahzadeh S, Motasaddi Zarandy M, Mohammadkhani G. Age-related hearing loss: An updated and comprehensive review of the interventions. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2024; 27:256-269. [PMID: 38333758 PMCID: PMC10849199 DOI: 10.22038/ijbms.2023.72863.15849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 07/17/2023] [Indexed: 02/10/2024]
Abstract
Aging causes progressive degenerative changes in many organs, particularly the auditory system. Several attempts have been conducted to investigate preventive and therapeutic strategy/strategies for age-related auditory dysfunction, such as maintaining a healthy lifestyle through good nutrition, lower anxiety levels, and noise exposure, different pharmacological approaches, gene and cell therapy, and other strategies. However, it is not clear which approach is the best to slow down these dysfunctions because several different underlying mechanistic pathways are associated with presbycusis which eventually leads to different types of this disease. A combination of several methods is probably required, whereas the effectiveness for some people needs to be monitored. The effectiveness of treatments will not be the same for all; therefore, we may need to have a unique and personalized approach to the prevention and treatment of ARHL for each person. In addition, each method needs to specify what type of presbycusis can prevent or treat and provide complete information about the extent, duration of treatment, persistency of treatment, side effects, and whether the approach is for treatment or prevention or even both. This paper reviews the updated literature, which targets current interventions for age-related hearing loss.
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Affiliation(s)
- Elham Tavanai
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
| | - Vida Rahimi
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ehsan Khalili
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
| | - Somayeh Falahzadeh
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
- Department of Audiology, School of Rehabilitation, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Masoud Motasaddi Zarandy
- Otolaryngology Research Center, Amiralam Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ghassem Mohammadkhani
- Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
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Lu Y, Hu Y, Wang S, Pan S, An K, Wang T, He Y, Tian C, Lei J. Hereditary Hearing Loss: A Systematic Review of Potential Treatments and Interventions. Am J Audiol 2023; 32:972-989. [PMID: 37889166 DOI: 10.1044/2023_aja-23-00069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023] Open
Abstract
PURPOSE The purpose of this study was to systematically review the research literature with regards to treatments and intervention methods for hereditary hearing loss. Our goal was to provide reference guidelines for the rational use of medication and gene-targeted therapy for patients with hereditary hearing loss and discuss the future development of research in this area. METHOD We searched two core databases, PubMed and Web of Science, for relevant literature relating to potential treatments and interventional methods for hereditary hearing loss. Then, we used Microsoft Excel to perform basic statistical analysis of the data, the R language to perform bibliometric analyses, and VOSviewer and CiteSpace to visualize data. In addition, we clustered and descriptively analyzed the data and identified the relative importance of each approach with regard to precise patient outcomes. RESULTS In this study, we followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standardized screening process and identified a total of 103 research articles. The average annual growth rate of publications in this area was 12.73%. The country with the highest number of publications and citations was the United States; 80 of these publications (associated with 76.92% of funding) were supported by grants from 16 countries. Potential treatments and interventions were clustered according to the stage of research and showed that 8.74% remain in the research design stage, 59.22% are in the clinical validation stage, and 32.04% are being applied in the clinic. The main research focus in this field is cochlear implants and gene therapy. CONCLUSIONS Hereditary hearing loss is in a critical period of transition from preventive to therapeutic research. Gene-targeted interventions represent one of the most promising and effective treatments. SUPPLEMENTAL MATERIAL https://doi.org/10.23641/asha.24309193.
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Affiliation(s)
- Yang Lu
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yuanjia Hu
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Shengyue Wang
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Sijia Pan
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Kai An
- Peking University Third Hospital, Beijing, China
- Center for Medical Informatics, Peking University, Beijing, China
| | - Tong Wang
- Department of Medical Informatics, School of Public Health, Jilin University, Changchun, China
| | - Yunfan He
- School of Public Health, Zhejiang University, Hangzhou City, China
| | - Chenghua Tian
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jianbo Lei
- Center for Medical Informatics, Peking University, Beijing, China
- Institute of Medical Technology, Peking University, Beijing, China
- School of Medical Informatics and Engineering, Southwest Medical University, Luzhou, China
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Tan WJT, Santos-Sacchi J, Tonello J, Shanker A, Ivanova AV. Pharmacological Modulation of Energy and Metabolic Pathways Protects Hearing in the Fus1/Tusc2 Knockout Model of Mitochondrial Dysfunction and Oxidative Stress. Antioxidants (Basel) 2023; 12:1225. [PMID: 37371955 DOI: 10.3390/antiox12061225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/23/2023] [Accepted: 05/31/2023] [Indexed: 06/29/2023] Open
Abstract
Tightly regulated and robust mitochondrial activities are critical for normal hearing. Previously, we demonstrated that Fus1/Tusc2 KO mice with mitochondrial dysfunction exhibit premature hearing loss. Molecular analysis of the cochlea revealed hyperactivation of the mTOR pathway, oxidative stress, and altered mitochondrial morphology and quantity, suggesting compromised energy sensing and production. Here, we investigated whether the pharmacological modulation of metabolic pathways using rapamycin (RAPA) or 2-deoxy-D-glucose (2-DG) supplementation can protect against hearing loss in female Fus1 KO mice. Additionally, we aimed to identify mitochondria- and Fus1/Tusc2-dependent molecular pathways and processes critical for hearing. We found that inhibiting mTOR or activating alternative mitochondrial energetic pathways to glycolysis protected hearing in the mice. Comparative gene expression analysis revealed the dysregulation of critical biological processes in the KO cochlea, including mitochondrial metabolism, neural and immune responses, and the cochlear hypothalamic-pituitary-adrenal axis signaling system. RAPA and 2-DG mostly normalized these processes, although some genes showed a drug-specific response or no response at all. Interestingly, both drugs resulted in a pronounced upregulation of critical hearing-related genes not altered in the non-treated KO cochlea, including cytoskeletal and motor proteins and calcium-linked transporters and voltage-gated channels. These findings suggest that the pharmacological modulation of mitochondrial metabolism and bioenergetics may restore and activate processes critical for hearing, thereby protecting against hearing loss.
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Affiliation(s)
- Winston J T Tan
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand
- Department of Surgery (Otolaryngology), Yale University School of Medicine, New Haven, CT 06510, USA
| | - Joseph Santos-Sacchi
- Department of Surgery (Otolaryngology), Yale University School of Medicine, New Haven, CT 06510, USA
| | - Jane Tonello
- School of Medicine, Meharry Medical College, Nashville, TN 37208, USA
| | - Anil Shanker
- School of Medicine, Meharry Medical College, Nashville, TN 37208, USA
| | - Alla V Ivanova
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA
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Wang K, Liu H, Hu Q, Wang L, Liu J, Zheng Z, Zhang W, Ren J, Zhu F, Liu GH. Epigenetic regulation of aging: implications for interventions of aging and diseases. Signal Transduct Target Ther 2022; 7:374. [PMID: 36336680 PMCID: PMC9637765 DOI: 10.1038/s41392-022-01211-8] [Citation(s) in RCA: 135] [Impact Index Per Article: 67.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/14/2022] [Accepted: 09/28/2022] [Indexed: 11/09/2022] Open
Abstract
Aging is accompanied by the decline of organismal functions and a series of prominent hallmarks, including genetic and epigenetic alterations. These aging-associated epigenetic changes include DNA methylation, histone modification, chromatin remodeling, non-coding RNA (ncRNA) regulation, and RNA modification, all of which participate in the regulation of the aging process, and hence contribute to aging-related diseases. Therefore, understanding the epigenetic mechanisms in aging will provide new avenues to develop strategies to delay aging. Indeed, aging interventions based on manipulating epigenetic mechanisms have led to the alleviation of aging or the extension of the lifespan in animal models. Small molecule-based therapies and reprogramming strategies that enable epigenetic rejuvenation have been developed for ameliorating or reversing aging-related conditions. In addition, adopting health-promoting activities, such as caloric restriction, exercise, and calibrating circadian rhythm, has been demonstrated to delay aging. Furthermore, various clinical trials for aging intervention are ongoing, providing more evidence of the safety and efficacy of these therapies. Here, we review recent work on the epigenetic regulation of aging and outline the advances in intervention strategies for aging and age-associated diseases. A better understanding of the critical roles of epigenetics in the aging process will lead to more clinical advances in the prevention of human aging and therapy of aging-related diseases.
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Affiliation(s)
- Kang Wang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Huicong Liu
- School of Biomedical Engineering, Shanghai Jiao Tong University, 200030, Shanghai, China
| | - Qinchao Hu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, 100101, Beijing, China
- Hospital of Stomatology, Sun Yat-sen University, 510060, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, 510060, Guangzhou, China
| | - Lingna Wang
- School of Biomedical Engineering, Shanghai Jiao Tong University, 200030, Shanghai, China
| | - Jiaqing Liu
- School of Biomedical Engineering, Shanghai Jiao Tong University, 200030, Shanghai, China
| | - Zikai Zheng
- University of Chinese Academy of Sciences, 100049, Beijing, China
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, 100101, Beijing, China
| | - Weiqi Zhang
- University of Chinese Academy of Sciences, 100049, Beijing, China
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, 100101, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, 100101, Beijing, China
| | - Jie Ren
- University of Chinese Academy of Sciences, 100049, Beijing, China.
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, 100101, Beijing, China.
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, 100101, Beijing, China.
| | - Fangfang Zhu
- School of Biomedical Engineering, Shanghai Jiao Tong University, 200030, Shanghai, China.
| | - Guang-Hui Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China.
- University of Chinese Academy of Sciences, 100049, Beijing, China.
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, 100101, Beijing, China.
- Advanced Innovation Center for Human Brain Protection, National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital, Capital Medical University, 100053, Beijing, China.
- Beijing Institute for Stem Cell and Regenerative Medicine, 100101, Beijing, China.
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Noise overstimulation of young adult UMHET4 mice accelerates age-related hearing loss. Hear Res 2022; 424:108601. [PMID: 36126618 DOI: 10.1016/j.heares.2022.108601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 08/16/2022] [Accepted: 09/03/2022] [Indexed: 11/22/2022]
Abstract
Many factors contribute to hearing loss commonly found in older adults. There can be natural aging of cellular elements, hearing loss previously induced by environmental factors such as noise or ototoxic drugs as well as genetic and epigenetic influences. Even when noise overstimulation does not immediately cause permanent hearing loss it has recently been shown to increase later age-related hearing loss (ARHL). The present study further investigated this condition in the UMHET4 mouse model by comparing a small arms fire (SAF)-like impulse noise exposure that has the greatest immediate effect in more apical cochlear regions to a broadband noise (BBN) exposure that has the greatest immediate effect in more basal cochlear regions. Both noise exposures were given at levels that only induced temporary auditory brainstem response (ABR) threshold shifts (TS). Mice were noise exposed at 5 months of age followed by ABR assessment at 6, 12, 18, 21, and 24 months of age. Mice that received the SAF-like impulse noise had accelerated age-related TS at 4 kHz that appeared at 12 months of age (significantly increased compared to no-noise controls). This increased TS at 4 kHz continued at 18 and 21 months but was no longer significantly greater at 24 months of age. The SAF-like impulse noise also induced a significantly greater mean TS at 48 kHz, first appearing at 18 months of age and continuing to be significantly greater than controls at 21 and 24 months. The BBN induced a different pace and pattern of enhanced age-related ABR TS. The mean TS for the BBN group first became significantly greater than controls at 18 months of age and only at 48 kHz. It remained significantly greater than controls at 21 months but was no longer significantly greater at 24 months of age. Results, therefore, show different influences on ARHL for the two different noise exposure conditions. Noise-induced enhancement appears to provide more an acceleration than overall total increase in ARHL.
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Activation of Rictor/mTORC2 signaling acts as a pivotal strategy to protect against sensorineural hearing loss. Proc Natl Acad Sci U S A 2022; 119:e2107357119. [PMID: 35238644 PMCID: PMC8917383 DOI: 10.1073/pnas.2107357119] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Significance The mechanistic target of rapamycin (mTOR) plays a central role in growth, metabolism, and aging. It is assembled into two multiprotein complexes, namely, mTORC1 and mTORC2. We previously demonstrated the efficacy of sirolimus in ARHL in mice by decreasing mTORC1. However, the aspect of mTORC2 regulation in the cochlea is poorly characterized. Herein, based on pharmacological and genetic interventions, we found that a high dose of sirolimus resulted in severe hearing loss by reducing the mTORC2/AKT signaling pathway in the cochlea. Furthermore, selective activation of mTORC2 could protect against hearing loss induced by acoustic trauma and cisplatin-induced ototoxicity. Hence, the therapeutic activation of mTORC2 in conjunction with decreasing mTORC1 might represent a promising and effective strategy in preventing hearing loss.
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Xiong H, Pang J, Min X, Ye Y, Lai L, Zheng Y. miR-34a/ATG9A/TFEB signaling modulates autophagy in cochlear hair cells and correlates with age-related hearing loss. Neuroscience 2022; 491:98-109. [DOI: 10.1016/j.neuroscience.2022.03.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 10/18/2022]
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Zhang Y, Zhang J, Wang S. The Role of Rapamycin in Healthspan Extension via the Delay of Organ Aging. Ageing Res Rev 2021; 70:101376. [PMID: 34089901 DOI: 10.1016/j.arr.2021.101376] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 05/07/2021] [Accepted: 05/30/2021] [Indexed: 12/17/2022]
Abstract
Aging can not only shorten a healthy lifespan, but can also lead to multi-organ dysfunction and failure. Anti-aging is a complex and worldwide conundrum for eliminating the various pathologies of senility. The past decade has seen great progress in the understanding of the aging-associated signaling pathways and their application for developing anti-aging approaches. Currently, some drugs can improve quality of life. The activation of mammalian target of rapamycin (mTOR) signaling is one of the core and detrimental mechanisms related to aging; rapamycin can reduce the rate of aging, improve age-related diseases by inhibiting the mTOR pathway, and prolong lifespan and healthspan effectively. However, the current evidence for rapamycin in lifespan extension and organ aging is fragmented and scattered. In this review, we summarize the efficacy and safety of rapamycin in prolonging a healthy lifespan by systematically alleviating aging in multiple organ systems, i.e., the nervous, urinary, digestive, circulatory, motor, respiratory, endocrine, reproductive, integumentary and immune systems, to provide a theoretical basis for the future clinical application of rapamycin in anti-aging.
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Affiliation(s)
- Yan Zhang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; National Clinical Research Center for Obstetrical and Gynecological Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China; Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jinjin Zhang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; National Clinical Research Center for Obstetrical and Gynecological Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China; Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Shixuan Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; National Clinical Research Center for Obstetrical and Gynecological Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China; Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Huazhong University of Science and Technology, Wuhan, 430030, China.
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Cortada M, Levano S, Bodmer D. mTOR Signaling in the Inner Ear as Potential Target to Treat Hearing Loss. Int J Mol Sci 2021; 22:ijms22126368. [PMID: 34198685 PMCID: PMC8232255 DOI: 10.3390/ijms22126368] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 12/14/2022] Open
Abstract
Hearing loss affects many people worldwide and occurs often as a result of age, ototoxic drugs and/or excessive noise exposure. With a growing number of elderly people, the number of people suffering from hearing loss will also increase in the future. Despite the high number of affected people, for most patients there is no curative therapy for hearing loss and hearing aids or cochlea implants remain the only option. Important treatment approaches for hearing loss include the development of regenerative therapies or the inhibition of cell death/promotion of cell survival pathways. The mammalian target of rapamycin (mTOR) pathway is a central regulator of cell growth, is involved in cell survival, and has been shown to be implicated in many age-related diseases. In the inner ear, mTOR signaling has also started to gain attention recently. In this review, we will emphasize recent discoveries of mTOR signaling in the inner ear and discuss implications for possible treatments for hearing restoration.
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Affiliation(s)
- Maurizio Cortada
- Department of Biomedicine, University of Basel, Hebelstrasse 20, 4031 Basel, Switzerland; (M.C.); (S.L.)
| | - Soledad Levano
- Department of Biomedicine, University of Basel, Hebelstrasse 20, 4031 Basel, Switzerland; (M.C.); (S.L.)
| | - Daniel Bodmer
- Department of Biomedicine, University of Basel, Hebelstrasse 20, 4031 Basel, Switzerland; (M.C.); (S.L.)
- Clinic for Otorhinolaryngology, Head and Neck Surgery, University of Basel Hospital, Petersgraben 4, 4031 Basel, Switzerland
- Correspondence: ; Tel.: +41-61-328-76-03
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13
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Altschuler RA, Kabara L, Martin C, Kanicki A, Stewart CE, Kohrman DC, Dolan DF. Rapamycin Added to Diet in Late Mid-Life Delays Age-Related Hearing Loss in UMHET4 Mice. Front Cell Neurosci 2021; 15:658972. [PMID: 33897373 PMCID: PMC8058174 DOI: 10.3389/fncel.2021.658972] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/11/2021] [Indexed: 01/30/2023] Open
Abstract
Our previous study demonstrated rapamycin added to diet at 4 months of age had significantly less age-related outer hair cell loss in the basal half of the cochlea at 22 months of age compared to mice without rapamycin. The present study tested adding rapamycin to diet later in life, at 14 months of age, and added a longitudinal assessment of auditory brain stem response (ABR). The present study used UMHET4 mice, a 4 way cross in which all grandparental strains lack the Cdh23753A allele that predisposes to early onset, progressive hearing loss. UMHET4 mice typically have normal hearing until 16-17 months, then exhibit threshold shifts at low frequencies/apical cochlea and later in more basal high frequency regions. ABR thresholds at 4, 12, 24, and 48 kHz were assessed at 12, 18, and 24 months of age and compared to baseline ABR thresholds acquired at 5 months of age to determine threshold shifts (TS). There was no TS at 12 months of age at any frequency tested. At 18 months of age mice with rapamycin added to diet at 14 months had a significantly lower mean TS at 4 and 12 kHz compared to mice on control diet with no significant difference at 24 and 48 kHz. At 24 months of age, the mean 4 kHz TS in rapamycin diet group was no longer significantly lower than the control diet group, while the 12 kHz mean remained significantly lower. Mean TS at 24 and 48 kHz in the rapamycin diet group became significantly lower than in the control diet group at 24 months. Hair cell counts at 24 months showed large loss in the apical half of most rapamycin and control diet mice cochleae with no significant difference between groups. There was only mild outer hair cell loss in the basal half of rapamycin and control diet mice cochleae with no significant difference between groups. The results show that a later life addition of rapamycin can decrease age-related hearing loss in the mouse model, however, it also suggests that this decrease is a delay/deceleration rather than a complete prevention.
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Affiliation(s)
- Richard A Altschuler
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States.,VA Ann Arbor Health Care System, Ann Arbor, MI, United States.,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Lisa Kabara
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States
| | - Catherine Martin
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States
| | - Ariane Kanicki
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States
| | - Courtney E Stewart
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States.,VA Ann Arbor Health Care System, Ann Arbor, MI, United States
| | - David C Kohrman
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States
| | - David F Dolan
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States
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14
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Moore SJ, Murphy GG, Cazares VA. Turning strains into strengths for understanding psychiatric disorders. Mol Psychiatry 2020; 25:3164-3177. [PMID: 32404949 PMCID: PMC7666068 DOI: 10.1038/s41380-020-0772-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/23/2020] [Accepted: 04/29/2020] [Indexed: 12/12/2022]
Abstract
There is a paucity in the development of new mechanistic insights and therapeutic approaches for treating psychiatric disease. One of the major challenges is reflected in the growing consensus that risk for these diseases is not determined by a single gene, but rather is polygenic, arising from the action and interaction of multiple genes. Canonically, experimental models in mice have been designed to ascertain the relative contribution of a single gene to a disease by systematic manipulation (e.g., mutation or deletion) of a known candidate gene. Because these studies have been largely carried out using inbred isogenic mouse strains, in which there is no (or very little) genetic diversity among subjects, it is difficult to identify unique allelic variants, gene modifiers, and epigenetic factors that strongly affect the nature and severity of these diseases. Here, we review various methods that take advantage of existing genetic diversity or that increase genetic variance in mouse models to (1) strengthen conclusions of single-gene function; (2) model diversity among human populations; and (3) dissect complex phenotypes that arise from the actions of multiple genes.
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Affiliation(s)
- Shannon J Moore
- Michigan Neuroscience Institute & Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Geoffrey G Murphy
- Michigan Neuroscience Institute & Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
| | - Victor A Cazares
- Michigan Neuroscience Institute & Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
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15
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Palliyaguru DL, Moats JM, Di Germanio C, Bernier M, de Cabo R. Frailty index as a biomarker of lifespan and healthspan: Focus on pharmacological interventions. Mech Ageing Dev 2019; 180:42-48. [PMID: 30926563 DOI: 10.1016/j.mad.2019.03.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/09/2019] [Accepted: 03/25/2019] [Indexed: 12/18/2022]
Abstract
Although survival has been the focus of aging research for many years, the field is rapidly evolving towards incorporating healthspan and health indices in studies that explore aging-related outcomes. Frailty is one such measure that is tightly correlated with human aging. Several frailty measures have been developed that focus on phenotypes of aging, including physical, cognitive and metabolic health that define healthspan. The extent at which cumulative deficits associated with frailty predict functional characteristics of healthy aging and longevity is currently unknown. A growing consensus for the use of animal models has emerged to evaluate a composite measure of frailty that provides a translational basis to understanding human frailty. In this review, we will focus on the impact of several anti-aging interventions, some of which have been characterized as caloric restriction (CR) mimetics such as metformin, rapamycin, and resveratrol as well as more novel approaches that are emerging in the field - nicotinamide adenine dinucleotide precursors, small molecule activators of sirtuins, and senolytics - on a number of frailty measurements associated with aging-related outcomes in mice and discuss the translatability of such measures to human frailty.
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Affiliation(s)
- Dushani L Palliyaguru
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Jacqueline M Moats
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Clara Di Germanio
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Michel Bernier
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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