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Brutnell TP, Wang X, Bao J. Integrating pharmacogenomics into clinical trials of hearing disorders. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:2828. [PMID: 36456290 PMCID: PMC9648993 DOI: 10.1121/10.0015092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 09/26/2022] [Accepted: 10/20/2022] [Indexed: 06/17/2023]
Abstract
In 2019, the U.S. Food and Drug Administration issued guidance to increase the efficiency of drug development and support precision medicine, including tailoring treatments to those patients who will benefit based on genetic variation even in the absence of a documented mechanism of action. Although multiple advancements have been made in the field of pharmacogenetics (PGx) for other disease conditions, there are no approved PGx guidelines in the treatment of hearing disorders. In studies of noise-induced hearing loss (NIHL), some progress has been made in the last several years associating genomic loci with susceptibility to noise damage. However, the power of such studies is limited as the underlying physiological responses may vary considerably among the patient populations. Here, we have summarized previous animal studies to argue that NIHL subtyping is a promising strategy to increase the granularity of audiological assessments. By coupling this enhanced phenotyping capability with genetic association studies, we suggest that drug efficacy will be better predicted, increasing the likelihood of success in clinical trials when populations are stratified based on genetic variation or designed with multidrug combinations to reach a broader segment of individuals suffering or at risk from NIHL.
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Affiliation(s)
| | - Xinwen Wang
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio 44272, USA
| | - Jianxin Bao
- Gateway Biotechnology, St. Louis, Missouri 63132, USA
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Lu F, Wei L, Yang C, Qiao Y, Liu YS, Chen XD, Wang J, Shi ZH, Chen FQ, Zha DJ, Xue T. Nrg1/ErbB2 regulates differentiation and apoptosis of neural stem cells in the cochlear nucleus through PI3K/Akt pathway. Neurosci Lett 2021; 751:135803. [PMID: 33705930 DOI: 10.1016/j.neulet.2021.135803] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 02/09/2021] [Accepted: 03/01/2021] [Indexed: 12/21/2022]
Abstract
Sensorineural hearing loss (SNHL) is a common causes of disability. Neural stem cells (NSCs) from the cochlear nuclei have been considered to be a potential direction for the treatment of SNHL. Neuregulin 1 (NRG1)/ErbB2 signaling displays an essential role in nervous system development. In this study, we aimed to explore the roles of NRG1/ErbB2 in differentiation and apoptosis of cochlear nuclei NSCs. The data showed that the expression of NGR1 and ErbB2 in cochlear nuclei NSCs isolated from rats were increased with the age of rats. NRG1 treatment reduced the nestin-positive cells number, increased the MAP2-positive and GFAP-positive cells number, decreased the expression of cleaved-caspase-3, and increased the activation of PI3K/AKT. ErbB2 knockdown by lentiviral-mediated ErbB2 shRNA infection reversed the effect of NRG1 on cochlear nuclei NSCs. LY294002 administration further enhanced the effect of ErbB2 silencing on the expression of nestin, MAP2, GFAP and cleaved-caspase-3. Taken together, NRG1/ErbB2 regulates differentiation and apoptosis of cochlear nucleus NSCs through PI3K/Akt pathway.
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Affiliation(s)
- Fei Lu
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Li Wei
- Departments of Obstetrics and Gynecology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Chun Yang
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Yan Qiao
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Yong-Shou Liu
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Xiao-Dong Chen
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Jian Wang
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Zhao-Hui Shi
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Fu-Quan Chen
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China
| | - Ding-Jun Zha
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China.
| | - Tao Xue
- Departments of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, PR China.
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Su Z, Xiong H, Liu Y, Pang J, Lin H, Zhang W, Zheng Y. Transcriptomic analysis highlights cochlear inflammation associated with age-related hearing loss in C57BL/6 mice using next generation sequencing. PeerJ 2020; 8:e9737. [PMID: 32879802 PMCID: PMC7443093 DOI: 10.7717/peerj.9737] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 07/26/2020] [Indexed: 12/27/2022] Open
Abstract
Background In our aging society, age-related hearing loss (AHL) is the most common sensory disorder in old people. Much progress has been made in understanding the pathological process of AHL over the past few decades. However, the mechanism of cochlear degeneration during aging is still not fully understood. Methods Next generation sequencing technique was used to sequence the whole transcriptome of the cochlea of C57BL/6 mice, a mouse model of AHL. Differentially expressed genes (DEGs) were identified using the Cuffdiff software. GO and KEGG pathway enrichment analyses of the DEGs were implemented by using the GOseq R package and KOBAS software, respectively. Results A total of 731 genes (379 up- and 352 down-regulated) were revealed to be differentially expressed in the cochlea of aged mice compared to the young. Many genes associated with aging, apoptosis, necroptosis and particularly, inflammation were identified as being significantly modulated in the aged cochlea. GO and KEGG analyses of the upregulated DEGs revealed that the most enriched terms were associated with immune responses and inflammatory pathways, whereas many of the downregulated genes are involved in ion channel function and neuronal signaling. Real-time qPCR showed that H2O2 treatment significantly induced the expression of multiple inflammation and necroptosis-related genes in HEI-OC1 cells. Conclusion Using next generation sequencing, our transcriptomic analysis revealed the differences of gene expression pattern with age in the cochlea of C57BL/6 mice. Our study also revealed multiple immune and inflammatory transcriptomic changes during cochlear aging and provides new insights into the molecular mechanisms underlying cochlear inflammation in AHL.
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Affiliation(s)
- Zhongwu Su
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Institute of Hearing and Speech-Language Science, Sun Yat-sen University, Guangzhou, China
| | - Hao Xiong
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Institute of Hearing and Speech-Language Science, Sun Yat-sen University, Guangzhou, China
| | - Yi Liu
- Department of Otolaryngology, Guangdong Women and Children Hospital, Guangzhou, China
| | - Jiaqi Pang
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Institute of Hearing and Speech-Language Science, Sun Yat-sen University, Guangzhou, China
| | - Hanqing Lin
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Institute of Hearing and Speech-Language Science, Sun Yat-sen University, Guangzhou, China
| | - Weijian Zhang
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Institute of Hearing and Speech-Language Science, Sun Yat-sen University, Guangzhou, China
| | - Yiqing Zheng
- Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Institute of Hearing and Speech-Language Science, Sun Yat-sen University, Guangzhou, China
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Bao J, Yu Y, Li H, Hawks J, Szatkowski G, Dade B, Wang H, Liu P, Brutnell T, Spehar B, Tye-Murray N. Evidence for independent peripheral and central age-related hearing impairment. J Neurosci Res 2020; 98:1800-1814. [PMID: 32415883 DOI: 10.1002/jnr.24639] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/12/2020] [Accepted: 04/10/2020] [Indexed: 11/11/2022]
Abstract
Deleterious age-related changes in the central auditory nervous system have been referred to as central age-related hearing impairment (ARHI) or central presbycusis. Central ARHI is often assumed to be the consequence of peripheral ARHI. However, it is possible that certain aspects of central ARHI are independent from peripheral ARHI. A confirmation of this possibility could lead to significant improvements in current rehabilitation practices. The major difficulty in addressing this issue arises from confounding factors, such as other age-related changes in both the cochlea and central non-auditory brain structures. Because gap detection is a common measure of central auditory temporal processing, and gap detection thresholds are less influenced by changes in other brain functions such as learning and memory, we investigated the potential relationship between age-related peripheral hearing loss (i.e., audiograms) and age-related changes in gap detection. Consistent with previous studies, a significant difference was found for gap detection thresholds between young and older adults. However, among older adults, no significant associations were observed between gap detection ability and several other independent variables including the pure tone audiogram average, the Wechsler Adult Intelligence Scale-Vocabulary score, gender, and age. Statistical analyses showed little or no contributions from these independent variables to gap detection thresholds. Thus, our data indicate that age-related decline in central temporal processing is largely independent of peripheral ARHI.
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Affiliation(s)
- Jianxin Bao
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Yan Yu
- The First People's Hospital of Zhangjiagang, Zhangjiagang, China
| | - Hui Li
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - John Hawks
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Grace Szatkowski
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Bethany Dade
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Hao Wang
- Department of Statistics, Iowa State University, Ames, IA, USA
| | - Peng Liu
- Department of Statistics, Iowa State University, Ames, IA, USA
| | - Thomas Brutnell
- Department of Research and Development, Gateway Biotechnology Inc., St. Louis. MO, USA
| | - Brent Spehar
- Department of Otolaryngology-Head and Neck Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Nancy Tye-Murray
- Department of Otolaryngology-Head and Neck Surgery, Washington University in St. Louis, St. Louis, MO, USA
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5
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Zhang YM, Yang ZD, Yu YF. Effect of neuregulin-1 on the auditory cortex in adult C57BL/6J mice. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2020; 23:362-367. [PMID: 32440323 PMCID: PMC7229506 DOI: 10.22038/ijbms.2020.33656.8026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
OBJECTIVES We sought to explore whether neuregulin-1(NRG1) would have a protective effect on the auditory cortices of adult C57BL/6J mice. MATERIALS AND METHODS We used RTPCR and Western blot (WB) to detect the expression of NRG1 and ERBB4 (the receptor of NRG1) in the auditory cortices of C57BL/6J mice of different ages (6-8 weeks and 42-44 weeks). Three groups of 42-44 week-old C57BL/6J mice were intraperitoneally injected with mouse neurotrophic factor (m-NGF), NRG1, or saline for two months. We observed the ultrastructures of the auditory cortices of adult mice after treatment using transmission electron microscopy. Additionally, we observed expression of NRG1 in the auditory cortices by immunohistochemistry. RESULTS Expression of NRG1 and ERBB4 in the auditory cortices of C57BL/6J mice at the age of 42-44 weeks was lower compared with 6-8 week-old mice. The ultra-structures of the auditory cortices, including the neurons and myelin sheaths, as revealed by transmission electron microscopy were healthier in the m-NGF and NRG1 treatment groups than those in the saline group. We found that expression of NRG1 in the auditory cortices after treatment in the m-NGF and NRG1 groups, especially in the NRG1 group, was higher than that in the saline group. CONCLUSION We concluded that with increasing age, NRG1 in the auditory cortices of C57BL/6J mice gradually decreased, and that NRG1 had a protective effect on the auditory cortices in adult C57BL/J mice.
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Affiliation(s)
- Yun-Mei Zhang
- Department of Otolaryngology, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Zhen-Dong Yang
- Department of Otolaryngology, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Ya-Feng Yu
- Department of Otolaryngology, The First Affiliated Hospital of Soochow University, Suzhou 215006, China,Corresponding author: Ya-Feng Yu. Department of Otolaryngology, The First Affiliated Hospital of Soochow University, Suzhou 215006, China. Tel: +86-0512-67780370;
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β-Secretase BACE1 Is Required for Normal Cochlear Function. J Neurosci 2019; 39:9013-9027. [PMID: 31527119 DOI: 10.1523/jneurosci.0028-19.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 08/30/2019] [Accepted: 09/04/2019] [Indexed: 12/20/2022] Open
Abstract
Cleavage of amyloid precursor protein (APP) by β-secretase BACE1 initiates the production and accumulation of neurotoxic amyloid-β peptides, which is widely considered an essential pathogenic mechanism in Alzheimer's disease (AD). Here, we report that BACE1 is essential for normal auditory function. Compared with wild-type littermates, BACE1-/- mice of either sex exhibit significant hearing deficits, as indicated by increased thresholds and reduced amplitudes in auditory brainstem responses (ABRs) and decreased distortion product otoacoustic emissions (DPOAEs). Immunohistochemistry revealed aberrant synaptic organization in the cochlea and hypomyelination of auditory nerve fibers as predominant neuropathological substrates of hearing loss in BACE1-/- mice. In particular, we found that fibers of spiral ganglion neurons (SGN) close to the organ of Corti are disorganized and abnormally swollen. BACE1 deficiency also engenders organization defects in the postsynaptic compartment of SGN fibers with ectopic overexpression of PSD95 far outside the synaptic region. During postnatal development, auditory fiber myelination in BACE1-/- mice lags behind dramatically and remains incomplete into adulthood. We relate the marked hypomyelination to the impaired processing of Neuregulin-1 when BACE1 is absent. To determine whether the cochlea of adult wild-type mice is susceptible to AD treatment-like suppression of BACE1, we administered the established BACE1 inhibitor NB-360 for 6 weeks. The drug suppressed BACE1 activity in the brain, but did not impair hearing performance and, upon neuropathological examination, did not produce the characteristic cochlear abnormalities of BACE1-/- mice. Together, these data strongly suggest that the hearing loss of BACE1 knock-out mice represents a developmental phenotype.SIGNIFICANCE STATEMENT Given its crucial role in the pathogenesis of Alzheimer's disease (AD), BACE1 is a prime pharmacological target for AD prevention and therapy. However, the safe and long-term administration of BACE1-inhibitors as envisioned in AD requires a comprehensive understanding of the various physiological functions of BACE1. Here, we report that BACE1 is essential for the processing of auditory signals in the inner ear, as BACE1-deficient mice exhibit significant hearing loss. We relate this deficit to impaired myelination and aberrant synapse formation in the cochlea, which manifest during postnatal development. By contrast, prolonged pharmacological suppression of BACE1 activity in adult wild-type mice did not reproduce the hearing deficit or the cochlear abnormalities of BACE1 null mice.
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Fuentes-Santamaría V, Alvarado JC, Rodríguez-de la Rosa L, Juiz JM, Varela-Nieto I. Neuroglial Involvement in Abnormal Glutamate Transport in the Cochlear Nuclei of the Igf1 -/- Mouse. Front Cell Neurosci 2019; 13:67. [PMID: 30881288 PMCID: PMC6405628 DOI: 10.3389/fncel.2019.00067] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/11/2019] [Indexed: 12/25/2022] Open
Abstract
Insulin-like growth factor 1 (IGF-1) is a powerful regulator of synaptic activity and a deficit in this protein has a profound impact on neurotransmission, mostly on excitatory synapses in both the developing and mature auditory system. Adult Igf1−/− mice are animal models for the study of human syndromic deafness; they show altered cochlear projection patterns into abnormally developed auditory neurons along with impaired glutamate uptake in the cochlear nuclei, phenomena that probably reflect disruptions in neuronal circuits. To determine the cellular mechanisms that might be involved in regulating excitatory synaptic plasticity in 4-month-old Igf1−/− mice, modifications to neuroglia, astroglial glutamate transporters (GLTs) and metabotropic glutamate receptors (mGluRs) were assessed in the cochlear nuclei. The Igf1−/− mice show significant decreases in IBA1 (an ionized calcium-binding adapter) and glial fibrillary acidic protein (GFAP) mRNA expression and protein accumulation, as well as dampened mGluR expression in conjunction with enhanced glutamate transporter 1 (GLT1) expression. By contrast, no differences were observed in the expression of glutamate aspartate transporter (GLAST) between these Igf1−/− mice and their heterozygous or wildtype littermates. These observations suggest that congenital IGF-1 deficiency may lead to alterations in microglia and astrocytes, an upregulation of GLT1, and the downregulation of groups I, II and III mGluRs. Understanding the molecular, biochemical and morphological mechanisms underlying neuronal plasticity in a mouse model of hearing deficits will give us insight into new therapeutic strategies that could help to maintain or even improve residual hearing when human deafness is related to IGF-1 deficiency.
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Affiliation(s)
- Veronica Fuentes-Santamaría
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Juan C Alvarado
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Lourdes Rodríguez-de la Rosa
- Grupo de Neurobiología de la Audición, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), CIBER MP, Instituto de Salud Carlos III, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Universitario La Paz (IdiPAZ), Madrid, Spain
| | - José M Juiz
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Isabel Varela-Nieto
- Grupo de Neurobiología de la Audición, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), CIBER MP, Instituto de Salud Carlos III, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Universitario La Paz (IdiPAZ), Madrid, Spain
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Mostaid MS, Lloyd D, Liberg B, Sundram S, Pereira A, Pantelis C, Karl T, Weickert CS, Everall IP, Bousman CA. Neuregulin-1 and schizophrenia in the genome-wide association study era. Neurosci Biobehav Rev 2016; 68:387-409. [DOI: 10.1016/j.neubiorev.2016.06.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 05/30/2016] [Accepted: 06/03/2016] [Indexed: 12/22/2022]
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Radtke-Schuller S, Seeler S, Grothe B. Restricted loss of olivocochlear but not vestibular efferent neurons in the senescent gerbil (Meriones unguiculatus). Front Aging Neurosci 2015; 7:4. [PMID: 25762929 PMCID: PMC4327622 DOI: 10.3389/fnagi.2015.00004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 01/11/2015] [Indexed: 11/19/2022] Open
Abstract
Degeneration of hearing and vertigo are symptoms of age-related auditory and vestibular disorders reflecting multifactorial changes in the peripheral and central nervous system whose interplay remains largely unknown. Originating bilaterally in the brain stem, vestibular and auditory efferent cholinergic projections exert feedback control on the peripheral sensory organs, and modulate sensory processing. We studied age-related changes in the auditory and vestibular efferent systems by evaluating number of cholinergic efferent neurons in young adult and aged gerbils, and in cholinergic trigeminal neurons serving as a control for efferents not related to the inner ear. We observed a significant loss of olivocochlear (OC) neurons in aged compared to young adult animals, whereas the overall number of lateral superior olive (LSO) cells was not reduced in aging. Although the loss of lateral and medial olivocochlear (MOC) neurons was uniform and equal on both sides of the brain, there were frequency-related differences within the lateral olivocochlear (LOC) neurons, where the decline was larger in the medial limb of the superior olivary nucleus (high frequency representation) than in the lateral limb (middle-to-low frequency representation). In contrast, neither the number of vestibular efferent neurons, nor the population of motor trigeminal neurons were significantly reduced in the aged animals. These observations suggest differential effects of aging on the respective cholinergic efferent brainstem systems.
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Affiliation(s)
- Susanne Radtke-Schuller
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University Munich, Germany ; IFB German Center for Vertigo and Balance Disorders Munich, Germany
| | - Sabine Seeler
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University Munich, Germany
| | - Benedikt Grothe
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University Munich, Germany ; IFB German Center for Vertigo and Balance Disorders Munich, Germany
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10
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Tang X, Zhu X, Ding B, Walton JP, Frisina RD, Su J. Age-related hearing loss: GABA, nicotinic acetylcholine and NMDA receptor expression changes in spiral ganglion neurons of the mouse. Neuroscience 2013; 259:184-93. [PMID: 24316061 DOI: 10.1016/j.neuroscience.2013.11.058] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 11/13/2013] [Accepted: 11/26/2013] [Indexed: 11/26/2022]
Abstract
Age-related hearing loss - presbycusis - is the number one communication disorder and most prevalent neurodegenerative condition of our aged population. Although speech understanding in background noise is quite difficult for those with presbycusis, there are currently no biomedical treatments to prevent, delay or reverse this condition. A better understanding of the cochlear mechanisms underlying presbycusis will help lead to future treatments. Objectives of the present study were to investigate GABAA receptor subunit α1, nicotinic acetylcholine (nACh) receptor subunit β2, and N-methyl-d-aspartate (NMDA) receptor subunit NR1 mRNA and protein expression changes in spiral ganglion neurons (SGN) of the CBA/CaJ mouse cochlea, that occur in age-related hearing loss, utilizing quantitative immunohistochemistry and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) techniques. We found that auditory brainstem response (ABR) thresholds shifted over 40dB from 3 to 48kHz in old mice compared to young adults. DPOAE thresholds also shifted over 40dB from 6 to 49kHz in old mice, and their amplitudes were significantly decreased or absent in the same frequency range. SGN density decreased with age in basal, middle and apical turns, and SGN density of the basal turn declined the most. A positive correlation was observed between SGN density and ABR wave 1amplitude. mRNA and protein expression of GABAAR α1 and AChR β2 decreased with age in SGNs in the old mouse cochlea. mRNA and protein expression of NMDAR NR1 increased with age in SGNs of the old mice. These findings demonstrate that there are functionally-relevant age-related changes of GABAAR, nAChR, NMDAR expression in CBA mouse SGNs reflecting their degeneration, which may be related to functional changes in cochlear synaptic transmission with age, suggesting biological mechanisms for peripheral age-related hearing loss.
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Affiliation(s)
- X Tang
- Department of Otolaryngology Head and Neck Surgery, First Affiliated Hospital, Guangxi Medical University, 6 Shuangyong Road, Nanning, Guangxi, 530021, China; Department Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - X Zhu
- Department Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - B Ding
- Department Communication Sciences & Disorders, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - J P Walton
- Department Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, United States; Department Communication Sciences & Disorders, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - R D Frisina
- Department Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, United States; Department Communication Sciences & Disorders, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - J Su
- Department of Otolaryngology Head and Neck Surgery, First Affiliated Hospital, Guangxi Medical University, 6 Shuangyong Road, Nanning, Guangxi, 530021, China.
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12
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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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Perez P, Bao J. Why do hair cells and spiral ganglion neurons in the cochlea die during aging? Aging Dis 2011; 2:231-241. [PMID: 22396875 PMCID: PMC3295057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 02/18/2011] [Accepted: 02/18/2011] [Indexed: 05/31/2023] Open
Abstract
Age-related decline of cochlear function is mainly due to the loss of hair cells and spiral ganglion neurons (SGNs). Recent findings clearly indicate that survival of these two cell types during aging depends on genetic and environmental interactions, and this relationship is seen at the systemic, tissue, cellular, and molecular levels. At cellular and molecular levels, age-related loss of hair cells and SGNs can occur independently, suggesting distinct mechanisms for the death of each during aging. This mechanistic independence is also observed in the loss of medial olivocochlear efferent innervation and outer hair cells during aging, pointing to a universal independent cellular mechanism for age-related neuronal death in the peripheral auditory system. While several molecular signaling pathways are implicated in the age-related loss of hair cells and SGNs, studies with the ability to locally modify gene expression in these cell types are needed to address whether these signaling pathways have direct effects on hair cells and SGNs during aging. Finally, the issue of whether age-related loss of these cells occurs via typical apoptotic pathways requires further examination. As new studies in the field of aging reshape the framework for exploring these underpinnings, understanding of the loss of hair cells and SGNs associated with age and the interventions that can treat and prevent these changes will result in dramatic benefits for an aging population.
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Affiliation(s)
| | - Jianxin Bao
- Correspondence should be addressed to: Jianxin Bao, Ph.D., Department of Otolaryngology, Center for Aging, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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