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Foss CT, Olsen T, Bigelow J, Hasenstaub AR. Sst- and Vip-Cre mouse lines without age-related hearing loss. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.15.603003. [PMID: 39071442 PMCID: PMC11275752 DOI: 10.1101/2024.07.15.603003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
GABAergic interneurons, including somatostatin (SST) and vasoactive intestinal peptide (VIP) positive cells, play a crucial role in cortical circuit processing. Cre recombinase-mediated manipulation of these interneurons is facilitated by commercially available knock-in mouse strains such as Sst-IRES-Cre (Sst-Cre) and Vip-IRES-Cre (Vip-Cre). However, these strains are troublesome for hearing research because they are only available on the C57BL/6 genetic background, which suffer from early onset age-related hearing loss (AHL) due to a mutation of the Cdh23 gene. To overcome this limitation, we backcrossed Sst-Cre and Vip-Cre mice to CBA mice to create normal-hearing offspring with the desired Cre transgenes. We confirmed that in these "CBA Cre" lines, Cre drives appropriate expression of Cre-dependent genes, by crossing CBA Cre mice to Ai14 reporter mice. To assess the hearing capabilities of the CBA Cre mice, we measured auditory brainstem responses (ABRs) using clicks and tones. CBA Cre mice showed significantly lower ABR thresholds compared to C57 control mice at 3, 6, 9, and 12 months. In conclusion, our study successfully generated Sst-Cre and Vip-Cre mouse lines on the CBA background that will be valuable tools for investigating the roles of SST and VIP positive interneurons without the confounding effects of age-related hearing loss.
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Bakay WMH, Cervantes B, Lao-Rodríguez AB, Johannesen PT, Lopez-Poveda EA, Furness DN, Malmierca MS. How 'hidden hearing loss' noise exposure affects neural coding in the inferior colliculus of rats. Hear Res 2024; 443:108963. [PMID: 38308936 DOI: 10.1016/j.heares.2024.108963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 01/15/2024] [Accepted: 01/20/2024] [Indexed: 02/05/2024]
Abstract
Exposure to brief, intense sound can produce profound changes in the auditory system, from the internal structure of inner hair cells to reduced synaptic connections between the auditory nerves and the inner hair cells. Moreover, noisy environments can also lead to alterations in the auditory nerve or to processing changes in the auditory midbrain, all without affecting hearing thresholds. This so-called hidden hearing loss (HHL) has been shown in tinnitus patients and has been posited to account for hearing difficulties in noisy environments. However, much of the neuronal research thus far has investigated how HHL affects the response characteristics of individual fibres in the auditory nerve, as opposed to higher stations in the auditory pathway. Human models show that the auditory nerve encodes sound stochastically. Therefore, a sufficient reduction in nerve fibres could result in lowering the sampling of the acoustic scene below the minimum rate necessary to fully encode the scene, thus reducing the efficacy of sound encoding. Here, we examine how HHL affects the responses to frequency and intensity of neurons in the inferior colliculus of rats, and the duration and firing rate of those responses. Finally, we examined how shorter stimuli are encoded less effectively by the auditory midbrain than longer stimuli, and how this could lead to a clinical test for HHL.
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Affiliation(s)
- Warren M H Bakay
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain
| | - Blanca Cervantes
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; School of Medicine, University Anáhuac Puebla, Mexico
| | - Ana B Lao-Rodríguez
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain
| | - Peter T Johannesen
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain
| | - Enrique A Lopez-Poveda
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain; Department of Surgery, Faculty of Medicine, University of Salamanca, Spain
| | - David N Furness
- School of Life Sciences, Keele University, Keele, United Kingdom
| | - Manuel S Malmierca
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain; Department of Biology and Pathology, Faculty of Medicine, University of Salamanca, Spain.
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Hou S, Chen P, He J, Chen J, Zhang J, Mammano F, Yang J. Dietary intake of deuterium oxide decreases cochlear metabolism and oxidative stress levels in a mouse model of age-related hearing loss. Redox Biol 2022; 57:102472. [PMID: 36162258 PMCID: PMC9513171 DOI: 10.1016/j.redox.2022.102472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 09/06/2022] [Accepted: 09/08/2022] [Indexed: 11/15/2022] Open
Abstract
Age-related hearing loss (ARHL) is the most prevalent sensory disorder in the elderly. Currently, no treatment can effectively prevent or reverse ARHL. Aging auditory organs are often accompanied by exacerbated oxidative stress and metabolic deterioration. Here, we report the effect of deuterated oxygen (D2O), also known as "heavy water", mouse models of ARHL. Supplementing the normal mouse diet with 10% D2O from 4 to 9 weeks of age lowered hearing thresholds at selected frequencies in treated mice compared to untreated control group. Oxidative stress levels were significantly reduced and in the cochlear duct of treated vs. untreated mice. Through metabolic flux analysis, we found that D2O mainly slowed down catabolic reactions, and may delay metabolic deterioration related to aging to a certain extent. Experiments confirmed that the Nrf2/HO-1/glutathione axis was down-regulated in treated mice. Thus, D2O supplementation can hinder ARHL progression in mouse models by slowing the pace of metabolism and reducing endogenous oxidative stress production in the cochlea. These findings open new avenues for protecting the cochlea from oxidative stress and regulating metabolism to prevent ARHL.
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Affiliation(s)
- Shule Hou
- Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Jiaotong University School of Medicine Ear Institute, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Penghui Chen
- Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Jiaotong University School of Medicine Ear Institute, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Jingchun He
- Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Jiaotong University School of Medicine Ear Institute, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Junmin Chen
- Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Jiaotong University School of Medicine Ear Institute, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Jifang Zhang
- Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Jiaotong University School of Medicine Ear Institute, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Fabio Mammano
- Department of Physics and Astronomy "G. Galilei", University of Padua, Padova, Italy; Department of Biomedical Sciences, Institute of Cell Biology and Neurobiology, Italian National Research Council, Monterotondo, Italy.
| | - Jun Yang
- Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Jiaotong University School of Medicine Ear Institute, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
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Fabrizio-Stover EM, Nichols G, Corcoran J, Jain A, Burghard AL, Lee CM, Oliver DL. Comparison of two behavioral tests for tinnitus assessment in mice. Front Behav Neurosci 2022; 16:995422. [PMID: 36299293 PMCID: PMC9588978 DOI: 10.3389/fnbeh.2022.995422] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/20/2022] [Indexed: 01/10/2023] Open
Abstract
Animal research focused on chronic tinnitus associated with noise-induced hearing loss can be expensive and time-consuming as a result of the behavioral training required. Although there exist a number of behavioral tests for tinnitus; there have been few formal direct comparisons of these tests. Here, we evaluated animals in two different tinnitus assessment methods. CBA/CaJ mice were trained in an operant conditioning, active avoidance (AA) test, and a reflexive, gap-induced pre-pulse inhibition of acoustic startle (GPIAS) test, or both. Tinnitus was induced in awake mice by unilateral continuous sound exposure using a 2-kHz- or 12 octave-wide noise centered at 16 kHz and presented at 113- or 116-dB SPL. Tinnitus was assessed 8 weeks after sound overexposure. Most mice had evidence of tinnitus behavior in at least one of the two behaviors. Of the mice evaluated in AA, over half (55%) had tinnitus positive behavior. In GPIAS, fewer animals (13%) were positive than were identified using the AA test. Few mice were positive in both tests (10%), and only one was positive for tinnitus behavior at the same spectral frequency in both tests. When the association between tinnitus behavior and spontaneous activity recorded in the inferior colliculus was compared, animals with tinnitus behavior in AA exhibited increased spontaneous activity, while those positive in GPIAS did not. Thus, it appears that operant conditioning tests, like AA, maybe more reliable and accurate tests for tinnitus than reflexive tests.
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Si Y, Ito S, Litke AM, Feldheim DA. High-Frequency Hearing Is Required to Compute a Topographic Map of Auditory Space in the Mouse Superior Colliculus. eNeuro 2022; 9:ENEURO.0513-21.2022. [PMID: 35473764 PMCID: PMC9116932 DOI: 10.1523/eneuro.0513-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/01/2022] [Accepted: 04/09/2022] [Indexed: 12/30/2022] Open
Abstract
A topographic map of auditory space is a feature found in the superior colliculus (SC) of many species, including CBA/CaJ mice. In this genetic background, high-frequency monaural spectral cues and interaural level differences (ILDs) are used to compute spatial receptive fields (RFs) that form a topographic map along the azimuth. Unfortunately, C57BL/6 mice, a strain widely used for transgenic manipulation, display age-related hearing loss (AHL) because of an inbred mutation in the Cadherin 23 gene (Cdh23) that affects hair cell mechanotransduction. To overcome this problem, researchers have used young C57BL/6 mice in their studies, as they have been shown to have normal hearing thresholds. However, important details of the auditory response characteristics of the SC such as spectral responses and spatial localization, have not been characterized in young C57BL/6 mice. Here, we show that two- to four-month C57BL/6 mice lack neurons with frontal auditory RFs and therefore lack a topographic representation of auditory space in the SC. Analysis of the spectrotemporal RFs (STRFs) of the SC auditory neurons shows that C57BL/6 mouse SC neurons lack the ability to detect the high-frequency (>40 kHz) spectral cues that are needed to compute frontal RFs. We also show that crossing C57BL/6 mice with CBA/CaJ mice or introducing one copy of the wild-type Cdh23 to C57BL/6 mice rescues the high-frequency hearing deficit and improves the topographic map of auditory space. Taken together, these results demonstrate the importance of high-frequency hearing in computing a topographic map of auditory space.
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Affiliation(s)
- Yufei Si
- The Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064
| | - Shinya Ito
- Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064
- MindScope Program, Allen Institute, Seattle, WA 98109
| | - Alan M Litke
- Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064
| | - David A Feldheim
- The Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064
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Wonkam A, Adadey SM, Schrauwen I, Aboagye ET, Wonkam-Tingang E, Esoh K, Popel K, Manyisa N, Jonas M, deKock C, Nembaware V, Cornejo Sanchez DM, Bharadwaj T, Nasir A, Everard JL, Kadlubowska MK, Nouel-Saied LM, Acharya A, Quaye O, Amedofu GK, Awandare GA, Leal SM. Exome sequencing of families from Ghana reveals known and candidate hearing impairment genes. Commun Biol 2022; 5:369. [PMID: 35440622 PMCID: PMC9019055 DOI: 10.1038/s42003-022-03326-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/25/2022] [Indexed: 12/15/2022] Open
Abstract
We investigated hearing impairment (HI) in 51 families from Ghana with at least two affected members that were negative for GJB2 pathogenic variants. DNA samples from 184 family members underwent whole-exome sequencing (WES). Variants were found in 14 known non-syndromic HI (NSHI) genes [26/51 (51.0%) families], five genes that can underlie either syndromic HI or NSHI [13/51 (25.5%)], and one syndromic HI gene [1/51 (2.0%)]. Variants in CDH23 and MYO15A contributed the most to HI [31.4% (16/51 families)]. For DSPP, an autosomal recessive mode of inheritance was detected. Post-lingual expression was observed for a family segregating a MARVELD2 variant. To our knowledge, seven novel candidate HI genes were identified (13.7%), with six associated with NSHI (INPP4B, CCDC141, MYO19, DNAH11, POTEI, and SOX9); and one (PAX8) with Waardenburg syndrome. MYO19 and DNAH11 were replicated in unrelated Ghanaian probands. Six of the novel genes were expressed in mouse inner ear. It is known that Pax8-/- mice do not respond to sound, and depletion of Sox9 resulted in defective vestibular structures and abnormal utricle development. Most variants (48/60; 80.0%) have not previously been associated with HI. Identifying seven candidate genes in this study emphasizes the potential of novel HI genes discovery in Africa.
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Affiliation(s)
- Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa.
- McKusick-Nathans Institute and Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Samuel Mawuli Adadey
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Elvis Twumasi Aboagye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Edmond Wonkam-Tingang
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Kevin Esoh
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Kalinka Popel
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Noluthando Manyisa
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Mario Jonas
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Carmen deKock
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Victoria Nembaware
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Diana M Cornejo Sanchez
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Thashi Bharadwaj
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Abdul Nasir
- Department of Molecular Science and Technology, Ajou University, Suwon-si, Republic of Korea
| | - Jenna L Everard
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Magda K Kadlubowska
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Liz M Nouel-Saied
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Anushree Acharya
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Osbourne Quaye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Geoffrey K Amedofu
- Department of Eye, Ear, Nose, and Throat, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Suzanne M Leal
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA.
- Taub Institute for Alzheimer's Disease and the Aging Brain, Columbia University Medical Centre, New York, NY, 10032, USA.
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Tan J, Kaiserman D, O'Leary SJ, Bird PI. Mice heterozygous for the Serpinb6a null mutation show deficits in central auditory function after acoustic trauma. Neuroreport 2021; 32:1287-1292. [PMID: 34554936 DOI: 10.1097/wnr.0000000000001727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Complete deficiency of the serine protease inhibitor gene, SERPINB6, is responsible for autosomal-recessive, nonsyndromic sensorineural hearing loss in humans. A mouse model of this deafness gene identifies Serpinb6a expression in the neurosensory epithelium and fibrocytes of the cochlea. Homozygous Serpinb6a mutant mice display an exaggerated hearing loss after exposure to moderate acoustic trauma. It is unknown if and how heterozygous Serpinb6a mice show increased vulnerability to acoustic trauma. METHODS We exposed Serpinb6a+/- and Serpinb6a+/+ mice to acoustic trauma and measured their hearing function prior to, 3 and 14 days postexposure, analysing shifts in hearing threshold and amplitudes of Wave I and II of the auditory brainstem-evoked response (ABR) to 4, 8, 16 and 32 kHz tones. RESULTS Shifts in hearing threshold and Wave I amplitude of Serpinb6a+/- mice were not significantly different from Serpinb6a+/+ mice at both time points and all frequencies tested (P > 0.05, Mann-Whitney test). However, Wave II amplitudes at 16 and 32 kHz tones, were more severely diminished in Serpinb6a+/- mice (P < 0.05). To exclude any effects of ageing on auditory function in Serpinb6a+/- mice, hearing function of unexposed Serpinb6a+/- mice was measured at start and end of the experimental period. The shift in Wave II amplitude of exposed Serpinb6a+/- mice was significantly lower than unexposed Serpinb6a+/- mice only at 16 and 32 kHz (P < 0.01), confirming acoustic trauma as the main cause of hearing deficits in Serpinb6a+/- mice. CONCLUSION These results suggest that heterozygous Serpinb6a humans may be vulnerable to noise.
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Affiliation(s)
- Justin Tan
- Department of Surgery, Otolaryngology, University of Melbourne, East Melbourne
| | - Dion Kaiserman
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Stephen J O'Leary
- Department of Surgery, Otolaryngology, University of Melbourne, East Melbourne
| | - Phillip I Bird
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
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Rescuing Auditory Temporal Processing with a Novel Augmented Acoustic Environment in an Animal Model of Congenital Hearing Loss. eNeuro 2021; 8:ENEURO.0231-21.2021. [PMID: 34155086 PMCID: PMC8281262 DOI: 10.1523/eneuro.0231-21.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/02/2021] [Indexed: 11/29/2022] Open
Abstract
Congenital sensorineural hearing loss (SNHL) affects thousands of infants each year and results in significant delays in speech and language development. Previous studies have shown that early exposure to a simple augmented acoustic environment (AAE) can limit the effects of progressive SNHL on hearing sensitivity. However, SNHL is also accompanied by hearing loss that is not assessed on standard audiological examinations, such as reduced temporal processing acuity. To assess whether sound therapy may improve these deficits, a mouse model of congenital SNHL was exposed to simple or temporally complex AAE. The DBA/2J mouse strain develops rapid, base to apex, progressive SNHL beginning at birth and is functionally deaf by six months of age. Hearing sensitivity and auditory brainstem function was measured using otoacoustic emissions, auditory brainstem response (ABR) and extracellular recording from the inferior colliculus (IC) in mice following exposure to 30 d of continuous AAE. Peripheral function and sound sensitivity in auditory midbrain neurons improved following exposure to both types of AAE. However, exposure to a novel, temporally complex AAE more strongly improved a measure of temporal processing acuity, neural gap-in-noise detection in the auditory midbrain. These experiments suggest that targeted sound therapy may be harnessed to improve hearing outcomes for children suffering from congenital SNHL.
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Beebe NL, Schofield BR. Cholinergic boutons are closely associated with excitatory cells and four subtypes of inhibitory cells in the inferior colliculus. J Chem Neuroanat 2021; 116:101998. [PMID: 34186203 DOI: 10.1016/j.jchemneu.2021.101998] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 01/23/2023]
Abstract
Acetylcholine (ACh) is a neuromodulator that has been implicated in multiple roles across the brain, including the central auditory system, where it sets neuronal excitability and gain and affects plasticity. In the cerebral cortex, subtypes of GABAergic interneurons are modulated by ACh in a subtype-specific manner. Subtypes of GABAergic neurons have also begun to be described in the inferior colliculus (IC), a midbrain hub of the auditory system. Here, we used male and female mice (Mus musculus) that express fluorescent protein in cholinergic cells, axons, and boutons to look at the association between ACh and four subtypes of GABAergic IC cells that differ in their associations with extracellular markers, their soma sizes, and their distribution within the IC. We found that most IC cells, including excitatory and inhibitory cells, have cholinergic boutons closely associated with their somas and proximal dendrites. We also found that similar proportions of each of four subtypes of GABAergic cells are closely associated with cholinergic boutons. Whether the different types of GABAergic cells in the IC are differentially regulated remains unclear, as the response of cells to ACh is dependent on which types of ACh receptors are present. Additionally, this study confirms the presence of these four subtypes of GABAergic cells in the mouse IC, as they had previously been identified only in guinea pigs. These results suggest that cholinergic projections to the IC modulate auditory processing via direct effects on a multitude of inhibitory circuits.
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Affiliation(s)
- Nichole L Beebe
- Hearing Research Focus Group, Northeast Ohio Medical University, Rootstown, OH, USA; Brain Health Research Institute, Kent State University, Kent, OH, USA.
| | - Brett R Schofield
- Hearing Research Focus Group, Northeast Ohio Medical University, Rootstown, OH, USA; Brain Health Research Institute, Kent State University, Kent, OH, USA.
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Biswas J, Pijewski RS, Makol R, Miramontes TG, Thompson BL, Kresic LC, Burghard AL, Oliver DL, Martinelli DC. C1ql1 is expressed in adult outer hair cells of the cochlea in a tonotopic gradient. PLoS One 2021; 16:e0251412. [PMID: 33979385 PMCID: PMC8115824 DOI: 10.1371/journal.pone.0251412] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/26/2021] [Indexed: 01/08/2023] Open
Abstract
Hearing depends on the transduction of sounds into neural signals by the inner hair cells of the cochlea. Cochleae also have outer hair cells with unique electromotile properties that increase auditory sensitivity, but they are particularly susceptible to damage by intense noise exposure, ototoxic drugs, and aging. Although the outer hair cells have synapses on afferent neurons that project to the brain, the function of this neuronal circuit is unclear. Here, we created a novel mouse allele that inserts a fluorescent reporter at the C1ql1 locus which revealed gene expression in the outer hair cells and allowed creation of outer hair cell-specific C1ql1 knockout mice. We found that C1ql1 expression in outer hair cells corresponds to areas with the most sensitive frequencies of the mouse audiogram, and that it has an unexpected adolescence-onset developmental timing. No expression was observed in the inner hair cells. Since C1QL1 in the brain is made by neurons, transported anterogradely in axons, and functions in the synaptic cleft, C1QL1 may serve a similar function at the outer hair cell afferent synapse. Histological analyses revealed that C1ql1 conditional knockout cochleae may have reduced outer hair cell afferent synapse maintenance. However, auditory behavioral and physiological assays did not reveal a compelling phenotype. Nonetheless, this study identifies a potentially useful gene expressed in the cochlea and opens the door for future studies aimed at elucidating the function of C1QL1 and the function of the outer hair cell and its afferent neurons.
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Affiliation(s)
- Joyshree Biswas
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Robert S. Pijewski
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Rohit Makol
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
- The Connecticut Institute for the Brain and Cognitive Sciences (IBACS), Storrs, CT, United States of America
| | - Tania G. Miramontes
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Brianna L. Thompson
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Lyndsay C. Kresic
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Alice L. Burghard
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Douglas L. Oliver
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - David C. Martinelli
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
- The Connecticut Institute for the Brain and Cognitive Sciences (IBACS), Storrs, CT, United States of America
- * E-mail:
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Group II Metabotropic Glutamate Receptors Modulate Sound Evoked and Spontaneous Activity in the Mouse Inferior Colliculus. eNeuro 2021; 8:ENEURO.0328-20.2020. [PMID: 33334826 PMCID: PMC7814476 DOI: 10.1523/eneuro.0328-20.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/22/2020] [Accepted: 11/24/2020] [Indexed: 01/02/2023] Open
Abstract
Little is known about the functions of Group II metabotropic glutamate receptors (mGluRs2/3) in the inferior colliculus (IC), a midbrain structure that is a major integration region of the central auditory system. We investigated how these receptors modulate sound-evoked and spontaneous firing in the mouse IC in vivo. We first performed immunostaining and tested hearing thresholds to validate vesicular GABA transporter (VGAT)-ChR2 transgenic mice on a mixed CBA/CaJ x C57BL/6J genetic background. Transgenic animals allowed for optogenetic cell-type identification. Extracellular single neuron recordings were obtained before and after pharmacological mGluR2/3 activation. We observed increased sound-evoked firing, as assessed by the rate-level functions (RLFs), in a subset of both GABAergic and non-GABAergic IC neurons following mGluR2/3 pharmacological activation. These neurons also displayed elevated spontaneous excitability and were distributed throughout the IC area tested, suggesting a widespread mGluR2/3 distribution in the mouse IC.
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Generation of a ChAT Cre mouse line without the early onset hearing loss typical of the C57BL/6J strain. Hear Res 2020; 388:107896. [PMID: 31982642 DOI: 10.1016/j.heares.2020.107896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/16/2019] [Accepted: 01/14/2020] [Indexed: 12/13/2022]
Abstract
The development of knockin mice with Cre recombinase expressed under the control of the promoter for choline acetyltransferase (ChAT) has allowed experimental manipulation of cholinergic circuits. However, currently available ChATCre mouse lines are on the C57BL/6J strain background, which shows early onset age-related hearing loss attributed to the Cdh23753A mutation (a.k.a., the ahl mutation). To develop ChATCre mice without accelerated hearing loss, we backcrossed ChATIRES-Cre mice with CBA/CaJ mice that have normal hearing. We used genotyping to obtain mice homozygous for ChATIRES-Cre and the wild-type allele at the Cdh23 locus (ChATCre,Cdh23WT). In the new line, auditory brainstem response thresholds were ∼20 dB lower than those in 9 month old ChATIRES-Cre mice at all frequencies tested (4-31.5 kHz). These thresholds were stable throughout the period of testing (3-12 months of age). We then bred ChATCre,Cdh23WT animals with Ai14 reporter mice to confirm the expression pattern of ChATCre. In these mice, tdTomato-labeled cells were observed in all brainstem regions known to contain cholinergic cells. We then stained the tissue with a neuron-specific marker, NeuN, to determine whether Cre expression was limited to neurons. Across several brainstem nuclei (pontomesencephalic tegmentum, motor trigeminal and facial nuclei), 100% of the tdTomato-labeled cells were double-labeled with anti-NeuN (n = 1896 cells), indicating Cre-recombinase was limited to neurons. Almost all of these cells (1867/1896 = 98.5%) also stained with antibodies against ChAT, indicating that reporter label was expressed almost exclusively in cholinergic neurons. Finally, an average 88.7% of the ChAT+ cells in these nuclei were labeled with tdTomato, indicating that the Cre is expressed in a large proportion of the cholinergic cells in these nuclei. We conclude that the backcrossed ChATCre,Cdh23WT mouse line has normal hearing and expresses Cre recombinase almost exclusively in cholinergic neurons. This ChATCre,Cdh23WT mouse line may provide an opportunity to manipulate cholinergic circuits without the confound of accelerated hearing loss associated with the C57BL/6J background. Furthermore, comparison with lines that do show early hearing loss may provide insight into possible cholinergic roles in age-related hearing loss.
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