201
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Li A, You D, Li W, Cui Y, He Y, Li W, Chen Y, Feng X, Sun S, Chai R, Li H. Novel compounds protect auditory hair cells against gentamycin-induced apoptosis by maintaining the expression level of H3K4me2. Drug Deliv 2019; 25:1033-1043. [PMID: 30799660 PMCID: PMC6058728 DOI: 10.1080/10717544.2018.1461277] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Aminoglycoside-induced hair cell (HC) loss is a major cause of hearing impairment, and the effective prevention of HC loss remains an unmet medical need. Epigenetic mechanisms have been reported to be involved in protecting cochlear cells against ototoxic drug injury, and in this study we developed new bioactive compounds that have similar chemical structures as the epigenetics-related lysine-specific demethylase 1 (LSD1) inhibitors. LSD1 inhibitors have been reported to protect cochlear cells by preventing demethylation of dimethylated histone H3K4 (H3K4me2). To determine whether these new compounds exert similar protective effects on HCs, we treated mouse cochlear explant cultures with the new compounds together with gentamycin. There was a severe loss of HCs in the organ of Corti after gentamycin exposure, while co-treatment with the new compounds significantly protected against gentamycin-induced HC loss. H3K4me2 levels in the nuclei of HCs decreased after exposure to gentamycin, but H3K4me2 levels were maintained in the presence of the new compounds. Apoptosis is also involved in the injury process, and the new compounds protected the inner ear HCs against apoptosis by reducing caspase-3 activation. Together, our findings demonstrate that our new compounds prevent gentamycin-induced HC loss by preventing the demethylation of H3K4me2 and by inhibiting apoptosis, and these results might provide the theoretical basis for novel drug development for hearing protection.
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Affiliation(s)
- Ao Li
- a ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital , Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University , Shanghai , China.,b Department of Otorhinolaryngology Head and Neck Surgery , Affiliated Drum Tower Hospital of Nanjing University Medical School, Research Institution of Otorhinolaryngology, Jiangsu Provincial Key Medical Discipline (Laboratory) , Nanjing , China
| | - Dan You
- a ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital , Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University , Shanghai , China
| | - Wenyan Li
- a ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital , Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University , Shanghai , China
| | - Yingjie Cui
- c Knowshine (Shanghai) Pharmaceuticals Inc , Shanghai , China
| | - Yingzi He
- a ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital , Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University , Shanghai , China
| | - Wen Li
- a ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital , Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University , Shanghai , China
| | - Yan Chen
- a ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital , Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University , Shanghai , China
| | - Xiao Feng
- c Knowshine (Shanghai) Pharmaceuticals Inc , Shanghai , China
| | - Shan Sun
- a ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital , Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University , Shanghai , China
| | - Renjie Chai
- d Key Laboratory for Developmental Genes and Human Disease , Ministry of Education, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Institute of Life Sciences, Southeast University , Nanjing , China.,e Co-innovation Center of Neuroregeneration, Nantong University , Nantong , China
| | - Huawei Li
- a ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital , Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University , Shanghai , China.,f Institutes of Biomedical Sciences and The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University , Shanghai , China
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202
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Deng X, Liu Z, Li X, Zhou Y, Hu Z. Generation of new hair cells by DNA methyltransferase (Dnmt) inhibitor 5-azacytidine in a chemically-deafened mouse model. Sci Rep 2019; 9:7997. [PMID: 31142766 PMCID: PMC6541592 DOI: 10.1038/s41598-019-44313-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 04/02/2019] [Indexed: 02/08/2023] Open
Abstract
Regeneration of mature mammalian inner ear hair cells remains to be a challenge. This study aims to evaluate the ability of DNA methyltransferase (Dnmt) inhibitor 5-azacytidine (5-aza) to generate outer hair cells (OHCs) in a chemically-deafened adult mouse model. 5-aza was administrated into the mouse inner ear via the round window. Immunofluorescence was used to examine the expression of hair cell specific proteins following 5-aza treatment. The results showed that in the chemically-deafened mouse cochlea, new OHCs were found post 5-aza treatment, whereas OHCs were completely lost in saline-treated mice. New hair cells expressed multiple hair cell markers included Myosin VIIa, Pou4f3 and Myosin VI. Newly-generated hair cells presented in three cochlear turns and were able to survive for at least six weeks. The effects of new hair cells generation by 5-aza were concentration dependent. Quantitative PCR study indicates that 5-aza may function through Dnmt1 inhibition. The results of this report suggest that the Dnmt inhibitor 5-aza may promote hair cell regeneration in a chemically-deafened mouse model.
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Affiliation(s)
- Xin Deng
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit, USA
| | - Zhenjie Liu
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit, USA
| | - Xiaoyang Li
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit, USA
| | - Yang Zhou
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit, USA
| | - Zhengqing Hu
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit, USA.
- John D. Dingell VA Medical Center, Detroit, Michigan, USA.
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203
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Rhee J, Han E, Rah YC, Park S, Koun S, Choi J. Evaluation of Ototoxicity of an Antifog Agent and the Suspected Underlying Mechanisms: An Animal Study. Ear Nose Throat J 2019; 98:NP131-NP137. [PMID: 31088301 DOI: 10.1177/0145561319850808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Use of rigid endoscopes has become widespread in middle ear surgeries, thereby attracting attention to the safety of antifog agents. However, few studies on the ototoxicity of antifog agents have been conducted. The purpose of this study was to evaluate hair cell damage and the underlying mechanisms caused by antifog agents using zebrafish larvae. We exposed zebrafish larvae at 3 days postfertilization to various concentrations of the antifog agent, Ultrastop (0.01, 0.02, 0.04, and 0.08%) for 72 hours. The average number of hair cells within 4 neuromasts of larvae, including supraorbital (SO1 and SO2), otic (O1), and occipital (OC1), in the control group were compared to those in the exposure groups. Significant hair cell loss was observed in the experimental groups compared to that in the control group (P < .01; control: 53.88 ± 4.85, 0.01%: 45.08 ± 11.70, 0.02%: 41.36 ± 12.00, 0.04%: 35.36 ± 16.18, and 0.08%: 15.60 ± 7.53 cells). Concentration-dependent increase in hair cell apoptosis by terminal deoxynucleotidyltransferase (TDT)-mediated dUTP-biotin nick end labeling assay (control: 0.00 ± 0.00, 0.01%: 3.48 ± 2.18, 0.02%: 9.64 ± 5.75, 0.04%: 17.72 ± 6.26, and 0.08%: 14.60 ± 8.18 cells) and decrease in the viability of hair cell mitochondria by 2-(4-[dimethylamino] styryl)-N-ethylpyridinium iodide assay (control: 9.61 ± 1.47, 0.01%: 8.28 ± 2.22, 0.02%: 8.45 ± 2.72, 0.04%: 7.25 ± 2.44, and 0.08%: 6.77 ± 3.26 percentage of total area) were observed. Antifog agent exposure can cause hair cell damage in zebrafish larvae, possibly by induction of mitochondrial damage with subsequent apoptosis of hair cells.
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Affiliation(s)
- Jihye Rhee
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea.,Department of Otorhinolaryngology-Head and Neck Surgery, Veterans Health Service Medical Center, Seoul, Republic of Korea
| | - Eunjung Han
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea.,Laboratory of Neurodevelopmental Genetics, Graduate School of Medicine, Korea University, Seoul, Republic of Korea
| | - Yoon Chan Rah
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
| | - Saemi Park
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
| | - Soonil Koun
- Biomedical Research Center, Korea University Ansan Hospital, Ansan, Republic of Korea
| | - June Choi
- Department of Otorhinolaryngology - Head and Neck Surgery, Korea University Ansan Hospital, Korea University, College of Medicine, Seoul, Republic of Korea
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204
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Bartsch TF, Hengel FE, Oswald A, Dionne G, Chipendo IV, Mangat SS, El Shatanofy M, Shapiro L, Müller U, Hudspeth AJ. Elasticity of individual protocadherin 15 molecules implicates tip links as the gating springs for hearing. Proc Natl Acad Sci U S A 2019; 116:11048-56. [PMID: 31072932 DOI: 10.1073/pnas.1902163116] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Our hearing depends on mechanosensitive channels in hair cells of the inner ear. Experiments suggest that each channel is opened by a “gating spring,” an elastic element that conveys displacement of a hair bundle to the channel. Appropriate stiffness of the gating spring permits the discrimination of different sound amplitudes; if the spring is too stiff, then a faint sound will elicit the same response as a loud sound, opening all of a cell’s channels. Although the tip link—a fine molecular filament—might be the gating spring, its properties have remained controversial. Using high-precision optical tweezers, we demonstrate that the mechanical properties of a tip link protein correlate with those of a gating spring in vivo. Hair cells, the sensory receptors of the inner ear, respond to mechanical forces originating from sounds and accelerations. An essential feature of each hair cell is an array of filamentous tip links, consisting of the proteins protocadherin 15 (PCDH15) and cadherin 23 (CDH23), whose tension is thought to directly gate the cell’s transduction channels. These links are considered far too stiff to represent the gating springs that convert hair bundle displacement into forces capable of opening the channels, and no mechanism has been suggested through which tip-link stiffness could be varied to accommodate hair cells of distinct frequency sensitivity in different receptor organs and animals. Consequently, the gating spring’s identity and mechanism of operation remain central questions in sensory neuroscience. Using a high-precision optical trap, we show that an individual monomer of PCDH15 acts as an entropic spring that is much softer than its enthalpic stiffness alone would suggest. This low stiffness implies that the protein is a significant part of the gating spring that controls a hair cell’s transduction channels. The tip link’s entropic nature then allows for stiffness control through modulation of its tension. We find that a PCDH15 molecule is unstable under tension and exhibits a rich variety of reversible unfolding events that are augmented when the Ca2+ concentration is reduced to physiological levels. Therefore, tip link tension and Ca2+ concentration are likely parameters through which nature tunes a gating spring’s mechanical properties.
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205
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Holman HA, Poppi LA, Frerck M, Rabbitt RD. Spontaneous and Acetylcholine Evoked Calcium Transients in the Developing Mouse Utricle. Front Cell Neurosci 2019; 13:186. [PMID: 31133810 PMCID: PMC6514437 DOI: 10.3389/fncel.2019.00186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
Spontaneous calcium transients are present during early postnatal development in the mouse retina and cochlea, and play an important role in maturation of the sensory organs and neural circuits in the central nervous system (CNS). It is not known whether similar calcium transients occur during postnatal development in the vestibular sensory organs. Here we demonstrate spontaneous intracellular calcium transients in sensory hair cells (HCs) and supporting cells (SCs) in the murine utricular macula during the first two postnatal weeks. Calcium transients were monitored using a genetically encoded calcium indicator, GCaMP5G (G5), at 100 ms-frame−1 in excised utricle sensory epithelia, including HCs, SCs, and neurons. The reporter line expressed G5 and tdTomato (tdT) in a Gad2-Cre dependent manner within a subset of utricular HCs, SCs and neurons. Kinetics of the G5 reporter limited temporal resolution to calcium events lasting longer than 200 ms. Spontaneous calcium transients lasting 1-2 s were observed in the expressing population of HCs at birth and slower spontaneous transients lasting 10-30 s appeared in SCs by P3. Beginning at P5, calcium transients could be modulated by application of the efferent neurotransmitter acetylcholine (ACh). In mature mice, calcium transients in the utricular macula occurred spontaneously, had a duration 1-2 s, and could be modulated by the exogenous application of acetylcholine (ACh) or muscarine. Long-lasting calcium transients evoked by ACh in mature mice were blocked by atropine, consistent with previous reports describing the role of muscarinic receptors expressed in calyx bearing afferents in efferent control of vestibular sensation. Large spontaneous and ACh evoked transients were reversibly blocked by the inositol trisphosphate receptor (IP3R) antagonist aminoethoxydiphenyl borate (2-APB). Results demonstrate long-lasting calcium transients are present in the utricular macula during the first postnatal week, and that responses to ACh mature over this same time period.
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Affiliation(s)
- Holly A Holman
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Lauren A Poppi
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,School of Biomedical Science and Pharmacy, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia
| | - Micah Frerck
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Richard D Rabbitt
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,Neuroscience Program, University of Utah, Salt Lake City, UT, United States.,Otolaryngology-Head and Neck Surgery, University of Utah, Salt Lake City, UT, United States
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206
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Abstract
In mammals, hair cells and spiral ganglion neurons (SGNs) in the cochlea together are sophisticated "sensorineural" structures that transduce auditory information from the outside world into the brain. Hair cells and SGNs are joined by glutamatergic ribbon-type synapses composed of a molecular machinery rivaling in complexity the mechanoelectric transduction components found at the apical side of the hair cell. The cochlear hair cell ribbon synapse has received much attention lately because of recent and important findings related to its damage (sometimes termed "synaptopathy") as a result of noise overexposure. During development, ribbon synapses between type I SGNs and inner hair cells form in the time window between birth and hearing onset and is a process coordinated with type I SGN myelination, spontaneous activity, synaptic pruning, and innervation by efferents. In this review, we highlight new findings regarding the diversity of type I SGNs and inner hair cell synapses, and the molecular mechanisms of selective hair cell targeting. Also discussed are cell adhesion molecules and protein constituents of the ribbon synapse, and how these factors participate in ribbon synapse formation. We also note interesting new insights into the morphological development of type II SGNs, and the potential for cochlear macrophages as important players in protecting SGNs. We also address recent studies demonstrating that the structural and physiological profiles of the type I SGNs do not reach full maturity until weeks after hearing onset, suggesting a protracted development that is likely modulated by activity.
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Affiliation(s)
- Thomas M. Coate
- Georgetown University, Department of Biology, 37th and O St. NW. Washington, DC. 20007. USA
| | - M. Katie Scott
- Department of Biological Sciences and Purdue Institute of Integrative Neuroscience, Purdue University, West Lafayette, Indiana 47907. USA
| | - Mansa C. Gurjar
- Georgetown University, Department of Biology, 37th and O St. NW. Washington, DC. 20007. USA
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207
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Jen HI, Hill MC, Tao L, Sheng K, Cao W, Zhang H, Yu HV, Llamas J, Zong C, Martin JF, Segil N, Groves AK. Transcriptomic and epigenetic regulation of hair cell regeneration in the mouse utricle and its potentiation by Atoh1. eLife 2019; 8:e44328. [PMID: 31033441 PMCID: PMC6504235 DOI: 10.7554/elife.44328] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/28/2019] [Indexed: 12/30/2022] Open
Abstract
The mammalian cochlea loses its ability to regenerate new hair cells prior to the onset of hearing. In contrast, the adult vestibular system can produce new hair cells in response to damage, or by reprogramming of supporting cells with the hair cell transcription factor Atoh1. We used RNA-seq and ATAC-seq to probe the transcriptional and epigenetic responses of utricle supporting cells to damage and Atoh1 transduction. We show that the regenerative response of the utricle correlates with a more accessible chromatin structure in utricle supporting cells compared to their cochlear counterparts. We also provide evidence that Atoh1 transduction of supporting cells is able to promote increased transcriptional accessibility of some hair cell genes. Our study offers a possible explanation for regenerative differences between sensory organs of the inner ear, but shows that additional factors to Atoh1 may be required for optimal reprogramming of hair cell fate.
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Affiliation(s)
- Hsin-I Jen
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Matthew C Hill
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Litao Tao
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Kuanwei Sheng
- Program in Integrative Molecular and Biomedical SciencesBaylor College of MedicineHoustonUnited States
| | - Wenjian Cao
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Hongyuan Zhang
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
| | - Haoze V Yu
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Juan Llamas
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Chenghang Zong
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - James F Martin
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of Molecular Physiology and BiophysicsBaylor College of MedicineHoustonUnited States
- The Texas Heart InstituteHoustonUnited States
| | - Neil Segil
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Andrew K Groves
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
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208
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Abstract
We review recent progress in using numerical models to relate utricular hair bundle and otoconial membrane (OM) structure to the functional requirements imposed by natural behavior in turtles. The head movements section reviews the evolution of experimental attempts to understand vestibular system function with emphasis on turtles, including data showing that accelerations occurring during natural head movements achieve higher magnitudes and frequencies than previously assumed. The structure section reviews quantitative anatomical data documenting topographical variation in the structures underlying macromechanical and micromechanical responses of the turtle utricle to head movement: hair bundles, OM, and bundle-OM coupling. The macromechanics section reviews macromechanical models that incorporate realistic anatomical and mechanical parameters and reveal that the system is significantly underdamped, contrary to previous assumptions. The micromechanics: hair bundle motion and met currents section reviews work based on micromechanical models, which demonstrates that topographical variation in the structure of hair bundles and OM, and their mode of coupling, result in regional specializations for signaling of low frequency (or static) head position and high frequency head accelerations. We conclude that computational models based on empirical data are especially promising for investigating mechanotransduction in this challenging sensorimotor system.
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Affiliation(s)
- Jong-Hoon Nam
- Department of Mechanical Engineering, Department of Biomedical Engineering, University of Rochester , Rochester, New York
| | - J W Grant
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia
| | - M H Rowe
- Department of Biology, Neuroscience Program, Quantitative Biology Institute, Ohio University , Athens, Ohio
| | - E H Peterson
- Department of Biology, Neuroscience Program, Quantitative Biology Institute, Ohio University , Athens, Ohio
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209
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Wang H, Qin Y, Zhang Y, Cui W, Lei Y, Ma X, Cheng Y, Shi L, Lv M. Decreased levels of superoxide dismutase in inner pillar cells contribute to ribbon synapse impairment in presbycusis. Am J Transl Res 2019; 11:2403-2412. [PMID: 31105846 PMCID: PMC6511776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 03/26/2019] [Indexed: 06/09/2023]
Abstract
OBJECTIVE To determine if decreased Cu/Zn superoxide dismutase (SOD1) levels in inner pillar cells is associated and diminished inner hair cell ribbon synapse plasticity in presbycusis. METHODS We evaluated the auditory brainstem responses (ABRs) of 2-, 5-, 6-, and 7-month-old C57BL/6J mice. ABRs were obtained using clicks and 4-, 12-, and 32-kHz tone bursts. Cochleae were collected immediately after audiometric assessment for Western blot analysis. The inner and outer hair cells and the inner hair cell ribbon synapses were separately counted. Frozen tissue sections were exposed to immunofluorescent staining for examine of SOD1 expression in the cochlea. RESULTS ABR thresholds were elevated in the 6- and 7-month groups. The maximal elevation was detected at 32 kHz. Distortion product otoacoustic emission amplitudes decreased in the mice at 5 months. SOD1 levels in the cochlea decreased as the mice aged. A reduction of SOD1 in the inner pillar cells was detected. Hair cell counting showed an apparent decrease in OHCs from 6 months onwards. The mean number of ribbon synapses was 17.2 ± 1.4, 17.7 ± 2.74, 12.8 ± 0.95, and 9.7 ± 3.08 in the 2-, 5-, 6-, and 7-month groups, respectively. This number significantly decreased with increasing age (P < 0.05). CONCLUSION Our study revealed that age-related hearing loss (ARHL) of C57BL/6J mice was caused by multi-site degeneration in the cochlea. Decreased expression of SOD1 in the cochlea is consistent with changes in the hearing threshold. Decreased SOD1 levels in the inner pillar cells may lead to diminished basilar membrane vibration and a reduction in the number of ribbon synapses, which plays an essential role in age-related hearing loss (ARHL).
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Affiliation(s)
- Haolin Wang
- Department of Otolaryngology, The First Affiliated Hospital of Dalian Medical UniversityDalian 116013, China
| | - Yuhong Qin
- Department of Otolaryngology, The First Affiliated Hospital of Dalian Medical UniversityDalian 116013, China
| | - Yue Zhang
- The Institute of Otolaryngology, Chinese PLA General HospitalBeijing 100853, China
| | - Wanming Cui
- Department of Otolaryngology, The First Affiliated Hospital of Dalian Medical UniversityDalian 116013, China
| | - Yu Lei
- Department of Otolaryngology, The First Affiliated Hospital of Dalian Medical UniversityDalian 116013, China
| | - Xiaorui Ma
- Department of Otolaryngology, Taiyuan Central Hospital of Shanxi Medical UniversityTaiyuan 030000, China
| | - Yu Cheng
- Department of Otolaryngology, The First Affiliated Hospital of Dalian Medical UniversityDalian 116013, China
| | - Lin Shi
- Department of Otolaryngology, The First Affiliated Hospital of Dalian Medical UniversityDalian 116013, China
| | - Mei Lv
- Department of Otolaryngology, The First Affiliated Hospital of Dalian Medical UniversityDalian 116013, China
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210
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Du ZH, Chen J, Chen QG, Zhou LQ, Bing D, Liu Y, Sun YB, Li PJ, Qi F, Zhu HM, Chu HQ. Expression Patterns and Implications of LaminB1 in Rat Cochleae. Curr Med Sci 2019; 39:305-309. [PMID: 31016526 DOI: 10.1007/s11596-019-2035-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/13/2019] [Indexed: 01/22/2023]
Abstract
LaminB1, a major component of the nuclear lamina, is a potent regulator of cellular proliferation and senescence and also known to be essential for neuronal migration and brain development. However, the expression patterns of LaminB1 in the rat cochleae are still not fully revealed. Utilizing immunofluorescence, Western blotting, and quantitative real-time PCR, we identified the distribution and expression of LaminB1 in the rat cochleae. Immunofluorescence staining indicated that LaminB1 was mainly localized in the auditory hair cells (HCs), spiral ganglion cells (SGC), stria vascularis (STV, including spiral ligament), Reissner's membrane (RM), and limbus laminae spiralis (LLS). Western blotting analysis illustrated that the distribution of LaminB1 in rat cochleae was characterized by tissue specificity. The LaminB1 protein was expressed more in SGC and basilar membrane (BM) than in STV. Meanwhile, the mRNA expression of LaminB1 displayed difference in cochlear tissues. These observations preliminarily revealed the expression patterns of LaminB1, providing a theoretical basis for further study on the role of LaminB1 in auditory function.
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Affiliation(s)
- Zhi-Hui Du
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jin Chen
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Qing-Guo Chen
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Liang-Qiang Zhou
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Dan Bing
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yun Liu
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yan-Bo Sun
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Peng-Jun Li
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Fan Qi
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Hong-Mei Zhu
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Han-Qi Chu
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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211
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Tobin M, Chaiyasitdhi A, Michel V, Michalski N, Martin P. Stiffness and tension gradients of the hair cell's tip-link complex in the mammalian cochlea. eLife 2019; 8:e43473. [PMID: 30932811 PMCID: PMC6464607 DOI: 10.7554/elife.43473] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/27/2019] [Indexed: 11/23/2022] Open
Abstract
Sound analysis by the cochlea relies on frequency tuning of mechanosensory hair cells along a tonotopic axis. To clarify the underlying biophysical mechanism, we have investigated the micromechanical properties of the hair cell's mechanoreceptive hair bundle within the apical half of the rat cochlea. We studied both inner and outer hair cells, which send nervous signals to the brain and amplify cochlear vibrations, respectively. We find that tonotopy is associated with gradients of stiffness and resting mechanical tension, with steeper gradients for outer hair cells, emphasizing the division of labor between the two hair-cell types. We demonstrate that tension in the tip links that convey force to the mechano-electrical transduction channels increases at reduced Ca2+. Finally, we reveal gradients in stiffness and tension at the level of a single tip link. We conclude that mechanical gradients of the tip-link complex may help specify the characteristic frequency of the hair cell.
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Affiliation(s)
- Mélanie Tobin
- Laboratoire Physico-Chimie CurieInstitut Curie, PSL Research University, CNRS UMR168ParisFrance
- Sorbonne UniversitéParisFrance
| | - Atitheb Chaiyasitdhi
- Laboratoire Physico-Chimie CurieInstitut Curie, PSL Research University, CNRS UMR168ParisFrance
- Sorbonne UniversitéParisFrance
| | - Vincent Michel
- Sorbonne UniversitéParisFrance
- Laboratoire de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM)ParisFrance
| | - Nicolas Michalski
- Sorbonne UniversitéParisFrance
- Laboratoire de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM)ParisFrance
| | - Pascal Martin
- Laboratoire Physico-Chimie CurieInstitut Curie, PSL Research University, CNRS UMR168ParisFrance
- Sorbonne UniversitéParisFrance
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212
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Dattoma T, Qualtieri A, Epifani G, De Vittorio M, Rizzi F. Design and Fabrication by Thermal Imprint Lithography and Mechanical Characterization of a Ring-Based PDMS Soft Probe for Sensing and Actuating Forces in Biological Systems. Polymers (Basel) 2019; 11:E424. [PMID: 30960408 DOI: 10.3390/polym11030424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/25/2019] [Accepted: 02/28/2019] [Indexed: 11/16/2022] Open
Abstract
In this paper, the design, fabrication and mechanical characterization of a novel polydimethylsiloxane (PDMS) soft probe for delivering and sensing forces in biological systems is proposed. On the basis of preliminary finite element (FEM) analysis, the design takes advantage of a suitable core geometry, characterized by a variable spring-like ring. The compliance of probes can be finely set in a wide range to measure forces in the micronewton to nanonewton range. In particular, this is accomplished by properly resizing the ring geometry and/or exploiting the mixing ratio-based elastic properties of PDMS. Fabrication by the thermal imprint lithography method allows fast and accurate tuning of ring sizes and tailoring of the contact section to their targets. By only varying geometrical parameters, the stiffness ranges from 1080 mNm-1 to 50 mNm-1, but by changing the base-curing agent proportion of the elastomer from 10:1 to 30:1, the stiffness drops to 37 mNm-1. With these compliances, the proposed device will provide a new experimental tool for investigating force-dependent biological functions in sensory systems.
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213
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Abstract
Mechanosensory hair cells of the zebrafish lateral line regenerate rapidly following damage. These renewed hair cells arise from the proliferation of surrounding support cells, which undergo symmetric division to produce two hair cell daughters. Given the continued regenerative capacity of the lateral line, support cells presumably have the ability to replenish themselves. Utilizing novel transgenic lines, we identified support cell populations with distinct progenitor identities. These populations show differences in their ability to generate new hair cells during homeostasis and regeneration. Targeted ablation of support cells reduced the number of regenerated hair cells. Furthermore, progenitors regenerated after targeted support cell ablation in the absence of hair cell damage. We also determined that distinct support cell populations are independently regulated by Notch signaling. The existence of independent progenitor populations could provide flexibility for the continued generation of new hair cells under a variety of conditions throughout the life of the animal.
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Affiliation(s)
- Eric D Thomas
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States
| | - David W Raible
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States.,Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, United States
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214
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Tadenev ALD, Akturk A, Devanney N, Mathur PD, Clark AM, Yang J, Tarchini B. GPSM2-GNAI Specifies the Tallest Stereocilia and Defines Hair Bundle Row Identity. Curr Biol 2019; 29:921-934.e4. [PMID: 30827920 DOI: 10.1016/j.cub.2019.01.051] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/12/2018] [Accepted: 01/21/2019] [Indexed: 12/12/2022]
Abstract
The transduction compartment of inner ear hair cells, the hair bundle, is composed of stereocilia rows of graded height, a property essential for sensory function that remains poorly understood at the molecular level. We previously showed that GPSM2-GNAI is enriched at stereocilia distal tips and required for their postnatal elongation and bundle morphogenesis-two characteristics shared with MYO15A (short isoform), WHRN, and EPS8 proteins. Here we first performed a comprehensive genetic analysis of the mouse auditory epithelium to show that GPSM2, GNAI, MYO15A, and WHRN operate in series within the same pathway. To understand how these functionally disparate proteins act as an obligate complex, we then systematically analyzed their distribution in normal and mutant bundles over time. We discovered that WHRN-GPSM2-GNAI is an extra module recruited by and added to a pre-existing MYO15A-EPS8 stereocilia tip complex. This extended complex is only present in the first, tallest row, and is required to stabilize larger amounts of MYO15A-EPS8 than in shorter rows, which at tips harbor only MYO15A-EPS8. In the absence of GPSM2 or GNAI function, including in the epistatic Myo15a and Whrn mutants, bundles retain an embryonic-like organization that coincides with generic stereocilia at the molecular level. We propose that GPSM2-GNAI confers on the first row its unique tallest identity and participates in generating differential row identity across the hair bundle.
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Affiliation(s)
| | - Anil Akturk
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | | | - Pranav Dinesh Mathur
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Anna M Clark
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Jun Yang
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA; Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT 84132, USA; Division of Otolaryngology, Department of Surgery, University of Utah, 50 North Medical Drive, Salt Lake City, UT 84132, USA
| | - Basile Tarchini
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; Department of Medicine, Tufts University, Boston, MA 02111, USA; Graduate School of Biomedical Science and Engineering (GSBSE), University of Maine, Orono, ME 04469, USA.
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215
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Liu H, Li G, Lu J, Gao YG, Song L, Li GL, Wu H. Cellular Differences in the Cochlea of CBA and B6 Mice May Underlie Their Difference in Susceptibility to Hearing Loss. Front Cell Neurosci 2019; 13:60. [PMID: 30873008 PMCID: PMC6400987 DOI: 10.3389/fncel.2019.00060] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/06/2019] [Indexed: 01/09/2023] Open
Abstract
Hearing is an extremely delicate sense that is particularly vulnerable to insults from environment, including drugs and noise. Unsurprisingly, mice of different genetic backgrounds show different susceptibility to hearing loss. In particular, CBA/CaJ (CBA) mice maintain relatively stable hearing over age while C57BL/6J (B6) mice show a steady decline of hearing, making them a popular model for early onset hearing loss. To reveal possible underlying mechanisms, we examined cellular differences in the cochlea of these two mouse strains. Although the ABR threshold and Wave I latency are comparable between them, B6 mice have a smaller Wave I amplitude. This difference is probably due to fewer spiral ganglion neurons found in B6 mice, as the number of ribbon synapses per inner hair cell (IHC) is comparable between the two mouse strains. Next, we compared the outer hair cell (OHC) function and we found OHCs from B6 mice are larger in size but the prestin density is similar among them, consistent with the finding that they share similar hearing thresholds. Lastly, we examined the IHC function and we found IHCs from B6 mice have a larger Ca2+ current, release more synaptic vesicles and recycle synaptic vesicles more quickly. Taken together, our results suggest that excessive exocytosis from IHCs in B6 mice may raise the probability of glutamate toxicity in ribbon synapses, which could accumulate over time and eventually lead to early onset hearing loss.
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Affiliation(s)
- Huihui Liu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Gen Li
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Jiawen Lu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Yun-Ge Gao
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Lei Song
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Geng-Lin Li
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Hao Wu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
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216
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Landin Malt A, Dailey Z, Holbrook-Rasmussen J, Zheng Y, Hogan A, Du Q, Lu X. Par3 is essential for the establishment of planar cell polarity of inner ear hair cells. Proc Natl Acad Sci U S A 2019; 116:4999-5008. [PMID: 30814219 DOI: 10.1073/pnas.1816333116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In the inner ear sensory epithelia, stereociliary hair bundles atop sensory hair cells are mechanosensory apparatus with planar polarized structure and orientation. This is established during development by the concerted action of tissue-level, intercellular planar cell polarity (PCP) signaling and a hair cell-intrinsic, microtubule-mediated machinery. However, how various polarity signals are integrated during hair bundle morphogenesis is poorly understood. Here, we show that the conserved cell polarity protein Par3 is essential for planar polarization of hair cells. Par3 deletion in the inner ear disrupted cochlear outgrowth, hair bundle orientation, kinocilium positioning, and basal body planar polarity, accompanied by defects in the organization and cortical attachment of hair cell microtubules. Genetic mosaic analysis revealed that Par3 functions both cell-autonomously and cell-nonautonomously to regulate kinocilium positioning and hair bundle orientation. At the tissue level, intercellular PCP signaling regulates the asymmetric localization of Par3, which in turn maintains the asymmetric localization of the core PCP protein Vangl2. Mechanistically, Par3 interacts with and regulates the localization of Tiam1 and Trio, which are guanine nucleotide exchange factors (GEFs) for Rac, thereby stimulating Rac-Pak signaling. Finally, constitutively active Rac1 rescued the PCP defects in Par3-deficient cochleae. Thus, a Par3-GEF-Rac axis mediates both tissue-level and hair cell-intrinsic PCP signaling.
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217
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Warchol ME, Massoodnia R, Pujol R, Cox BC, Stone JS. Development of hair cell phenotype and calyx nerve terminals in the neonatal mouse utricle. J Comp Neurol 2019; 527:1913-1928. [PMID: 30724338 DOI: 10.1002/cne.24658] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/26/2019] [Accepted: 02/01/2019] [Indexed: 01/03/2023]
Abstract
The vestibular organs of reptiles, birds, and mammals possess Type I and Type II sensory hair cells, which have distinct morphologies, physiology, and innervation. Little is known about how vestibular hair cells adopt a Type I or Type II identity or acquire proper innervation. One distinguishing marker is the transcription factor Sox2, which is expressed in all developing hair cells but persists only in Type II hair cells in maturity. We examined Sox2 expression and formation of afferent nerve terminals in mouse utricles between postnatal days 0 (P0) and P17. Between P3 and P14, many hair cells lost Sox2 immunoreactivity and the density of calyceal afferent nerve terminals (specific to Type I hair cells) increased in all regions of the utricle. At early time points, many calyces enclosed Sox2-labeled hair cells, while some Sox2-negative hair cells within the striola had not yet developed a calyx. These observations indicate that calyx maturation is not temporally correlated with loss of Sox2 expression in Type I hair cells. To determine which type(s) of hair cells are formed postnatally, we fate-mapped neonatal supporting cells by injecting Plp-CreER T2 :Rosa26 tdTomato mice with tamoxifen at P2 and P3. At P9, tdTomato-positive hair cells were immature and not classifiable by type. At P30, tdTomato-positive hair cells increased 1.8-fold compared to P9, and 91% of tdTomato-labeled hair cells were Type II. Our findings show that most neonatally-derived hair cells become Type II, and many Type I hair cells (formed before P2) downregulate Sox2 and acquire calyces between P0 and P14.
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Affiliation(s)
- Mark E Warchol
- Department of Otolaryngology, Washington University, St Louis, Missouri
| | - Roxanna Massoodnia
- Department of Otolaryngology-Head and Neck Surgery and the Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington
| | - Remy Pujol
- Department of Otolaryngology-Head and Neck Surgery and the Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington.,INSERM Unit 1051, Institute of Neuroscience, University of Montpellier, Montpellier, France
| | - Brandon C Cox
- Departments of Pharmacology and Surgery, Division of Otolaryngology, Southern Illinois University School of Medicine, Springfield, Illinois
| | - Jennifer S Stone
- Department of Otolaryngology-Head and Neck Surgery and the Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington
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218
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Ruhl D, Du TT, Wagner EL, Choi JH, Li S, Reed R, Kim K, Freeman M, Hashisaki G, Lukens JR, Shin JB. Necroptosis and Apoptosis Contribute to Cisplatin and Aminoglycoside Ototoxicity. J Neurosci 2019; 39:2951-64. [PMID: 30733218 DOI: 10.1523/JNEUROSCI.1384-18.2019] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 01/23/2019] [Accepted: 01/30/2019] [Indexed: 11/21/2022] Open
Abstract
Ototoxic side effects of cisplatin and aminoglycosides have been extensively studied, but no therapy is available to date. Sensory hair cells, upon exposure to cisplatin or aminoglycosides, undergo apoptotic and necrotic cell death. Blocking these cell death pathways has therapeutic potential in theory, but incomplete protection and lack of therapeutic targets in the case of necrosis, has hampered the development of clinically applicable drugs. Over the past decade, a novel form of necrosis, termed necroptosis, was established as an alternative cell death pathway. Necroptosis is distinguished from passive necrotic cell death, in that it follows a cellular program, involving the receptor-interacting protein kinase (RIPK) 1 and RIPK3. In this study, we used pharmacological and genetic interventions in the mouse to test the relative contributions of necroptosis and caspase-8-mediated apoptosis toward cisplatin and aminoglycoside ototoxicity. We find that ex vivo, only apoptosis contributes to cisplatin and aminoglycoside ototoxicity, while in vivo, necroptosis as well as apoptosis are involved in both sexes. Inhibition of necroptosis and apoptosis using pharmacological compounds is thus a viable strategy to ameliorate aminoglycoside and cisplatin ototoxicity.SIGNIFICANCE STATEMENT The clinical application of cisplatin and aminoglycosides is limited due to ototoxic side effects. Here, using pharmaceutical and genetic intervention, we present evidence that two types of programmed cell death, apoptosis and necroptosis, contribute to aminoglycoside and cisplatin ototoxicity. Key molecular factors mediating necroptosis are well characterized and druggable, presenting new avenues for pharmaceutical intervention.
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219
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Gu X, Chai R, Guo L, Dong B, Li W, Shu Y, Huang X, Li H. Transduction of Adeno-Associated Virus Vectors Targeting Hair Cells and Supporting Cells in the Neonatal Mouse Cochlea. Front Cell Neurosci 2019; 13:8. [PMID: 30733670 PMCID: PMC6353798 DOI: 10.3389/fncel.2019.00008] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 01/10/2019] [Indexed: 02/05/2023] Open
Abstract
Adeno-associated virus (AAV) is the preferred vector for gene therapy of hereditary deafness, and different viral serotypes, promoters and transduction pathways can influence the targeting of AAV to different types of cells and the expression levels of numerous exogenous genes. To determine the transduction and expression patterns of AAV with different serotypes or promoters in hair cells and supporting cells in the neonatal mouse cochlea, we examined the expression of enhanced green fluorescent protein (eGFP) for five different types of AAV vectors [serotypes 2, 9, and Anc80L65 with promoter cytomegalovirus (CMV)-beta-Globin and serotypes 2 and 9 with promoter chicken beta-actin (CBA)] in in vitro cochlear explant cultures and we tested the transduction of AAV2/2-CBA, AAV2/9-CBA, and AAV2/Anc80L65-CMV by in vivo microinjection into the scala media of the cochlea. We found that each AAV vector had its own transduction and expression characteristics in hair cells and supporting cells in different regions of the cochlea. There was a tonotopic gradient for the in vitro transduction of AAV2/2-CBA, AAV2/9-CBA, AAV2/2-CMV, and AAV2/9-CMV in outer hair cells (OHCs), with more OHCs expressing eGFP at the base of the cochlea than at the apex. AAV2/2-CBA in vitro and AAV2/Anc80L65-CMV in vivo induced more supporting cells expressing eGFP at the apex than in the base. We found that AAV vectors with different promoters had different expression efficacies in hair cells and supporting cells of the auditory epithelium. The CMV-beta-Globin promoter could drive the expression of the delivered construct more efficiently in hair cells, while the CBA promoter was more efficient in supporting cells. The in vitro and in vivo experiments both demonstrated that AAV2/Anc80L65-CMV was a very promising vector for gene therapy of deafness because of its high transduction rates in hair cells. These results might be useful for selecting the appropriate vectors for gene delivery into different types of inner ear cells and thus improving the effectiveness of gene therapy.
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Affiliation(s)
- Xi Gu
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.,Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Biao Dong
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Wenyan Li
- ENT Institute and Otorhinolaryngology Department, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Yilai Shu
- ENT Institute and Otorhinolaryngology Department, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Xinsheng Huang
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,Shanghai Engineering Research Center of Cochlear Implant, Shanghai, China.,The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
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220
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Urata S, Iida T, Yamamoto M, Mizushima Y, Fujimoto C, Matsumoto Y, Yamasoba T, Okabe S. Cellular cartography of the organ of Corti based on optical tissue clearing and machine learning. eLife 2019; 8:40946. [PMID: 30657453 PMCID: PMC6338463 DOI: 10.7554/elife.40946] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 01/05/2019] [Indexed: 12/20/2022] Open
Abstract
The highly organized spatial arrangement of sensory hair cells in the organ of Corti is essential for inner ear function. Here, we report a new analytical pipeline, based on optical clearing of tissue, for the construction of a single-cell resolution map of the organ of Corti. A sorbitol-based optical clearing method enabled imaging of the entire cochlea at subcellular resolution. High-fidelity detection and analysis of all hair cell positions along the entire longitudinal axis of the organ of Corti were performed automatically by machine learning–based pattern recognition. Application of this method to samples from young, adult, and noise-exposed mice extracted essential information regarding cellular pathology, including longitudinal and radial spatial characteristics of cell loss, implying that multiple mechanisms underlie clustered cell loss. Our method of cellular mapping is effective for system-level phenotyping of the organ of Corti under both physiological and pathological conditions.
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Affiliation(s)
- Shinji Urata
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Otolaryngology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tadatsune Iida
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masamichi Yamamoto
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yu Mizushima
- Department of Otolaryngology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Chisato Fujimoto
- Department of Otolaryngology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yu Matsumoto
- Department of Otolaryngology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tatsuya Yamasoba
- Department of Otolaryngology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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221
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Takago H, Oshima-Takago T, Moser T. Disruption of Otoferlin Alters the Mode of Exocytosis at the Mouse Inner Hair Cell Ribbon Synapse. Front Mol Neurosci 2019; 11:492. [PMID: 30687007 PMCID: PMC6338019 DOI: 10.3389/fnmol.2018.00492] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 12/19/2018] [Indexed: 11/24/2022] Open
Abstract
Sound encoding relies on Ca2+-mediated exocytosis at the ribbon synapse between cochlear inner hair cells (IHCs) and type I spiral ganglion neurons (SGNs). Otoferlin, a multi-C2 domain protein, is proposed to regulate Ca2+-triggered exocytosis at this synapse, but the precise mechanisms of otoferlin function remain to be elucidated. Here, performing whole-cell voltage-clamp recordings of excitatory postsynaptic currents (EPSCs) from SGNs in otoferlin mutant mice, we investigated the impact of Otof disruption at individual synapses with single release event resolution. Otof deletion decreased the spontaneous release rate and abolished the stimulus-secretion coupling. This was evident from failure of potassium-induced IHC depolarization to stimulate release and supports the proposed role of otoferlin in Ca2+ sensing for fusion. A missense mutation in the Otof gene (pachanga), in which otoferlin level at the IHC plasma membrane was lowered without changing its Ca2+ binding, also reduced the spontaneous release rate but spared the stimulus-secretion coupling. The slowed stimulated release rate supports the hypothesis that a sufficient abundance of otoferlin at the plasma membrane is crucial for the vesicle supply. Large-sized monophasic EPSCs remained present upon Otof deletion despite the drastic reduction of the rate of exocytosis. However, EPSC amplitude, on average, was modestly decreased. Moreover, a reduced contribution of multiphasic EPSC was observed in both Otof mutants. We argue that the presence of large monophasic EPSCs despite the exocytic defect upon Otof deletion supports the uniquantal hypothesis of transmitter release at the IHC ribbon synapse. Based upon the reduced contribution of multiphasic EPSC, we propose a role of otoferlin in regulating the mode of exocytosis in IHCs.
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Affiliation(s)
- Hideki Takago
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Department of Rehabilitation for Sensory Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.,Collaborative Research Center 889 Cellular Mechanisms of Sensory Processing, Göttingen, Germany
| | - Tomoko Oshima-Takago
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Department of Rehabilitation for Sensory Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.,Collaborative Research Center 889 Cellular Mechanisms of Sensory Processing, Göttingen, Germany.,Göttingen Graduate School for Neurosciences and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889 Cellular Mechanisms of Sensory Processing, Göttingen, Germany.,Göttingen Graduate School for Neurosciences and Molecular Biosciences, University of Göttingen, Göttingen, Germany.,Auditory Neuroscience Group, Max Planck Institute for Experimental Medicine, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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222
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Nam YH, Rodriguez I, Jeong SY, Pham TNM, Nuankaew W, Kim YH, Castañeda R, Jeong SY, Park MS, Lee KW, Lee JS, Kim DH, Park YH, Kim SH, Moon IS, Choung SY, Hong BN, Jeong KW, Kang TH. Avocado Oil Extract Modulates Auditory Hair Cell Function through the Regulation of Amino Acid Biosynthesis Genes. Nutrients 2019; 11:nu11010113. [PMID: 30626089 PMCID: PMC6356572 DOI: 10.3390/nu11010113] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 12/24/2018] [Accepted: 01/05/2019] [Indexed: 12/21/2022] Open
Abstract
Sensorineural hearing loss (SNHL) is one of the most common causes of disability, affecting over 466 million people worldwide. However, prevention or therapy of SNHL has not been widely studied. Avocado oil has shown many health benefits but it has not yet been studied in regards to SNHL. Therefore, we aimed to investigate the efficacy of avocado oil on SNHL in vitro and in vivo and elucidate its mode of action. For the present study, we used enhanced functional avocado oil extract (DKB122). DKB122 led to recovery of otic hair cells in zebrafish after neomycin-induced otic cell damage. Also, DKB122 improved auditory sensory transmission function in a mouse model of noise induced-hearing loss and protected sensory hair cells in the cochlea. In addition, RNA sequencing was performed to elucidate the mechanism involved. KEGG pathway enrichment analysis of differentially expressed genes showed that DKB122 protected House Ear Institute-Organ of Corti 1 (HEI-OC1) cells against neomycin-related alterations in gene expression due to oxidative stress, cytokine production and protein synthesis.
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MESH Headings
- Amino Acids/biosynthesis
- Animals
- Auditory Perception/drug effects
- Cochlea/cytology
- Cochlea/drug effects
- Cochlea/metabolism
- Gene Expression Regulation/drug effects
- Hair Cells, Auditory/drug effects
- Hair Cells, Auditory/metabolism
- Hair Cells, Auditory/physiology
- Hearing Loss, Noise-Induced/drug therapy
- Hearing Loss, Noise-Induced/genetics
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/physiopathology
- Hearing Loss, Sensorineural/drug therapy
- Hearing Loss, Sensorineural/genetics
- Hearing Loss, Sensorineural/metabolism
- Hearing Loss, Sensorineural/physiopathology
- Metabolic Networks and Pathways/drug effects
- Metabolic Networks and Pathways/genetics
- Mice
- Persea/chemistry
- Phytotherapy
- Plant Extracts/pharmacology
- Plant Extracts/therapeutic use
- Plant Oils/pharmacology
- Plant Oils/therapeutic use
- Sequence Analysis, RNA
- Zebrafish
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Affiliation(s)
- Youn Hee Nam
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Isabel Rodriguez
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Seo Yeon Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 21936, Korea.
| | - Thu Nguyen Minh Pham
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 21936, Korea.
| | - Wanlapa Nuankaew
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Yun Hee Kim
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Rodrigo Castañeda
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Seo Yule Jeong
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Min Seon Park
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Kye Wan Lee
- R&D Center, Dongkook Pharm. Co., Ltd., Gyeonggi 16229, Korea.
| | - Jung Suk Lee
- R&D Center, Dongkook Pharm. Co., Ltd., Gyeonggi 16229, Korea.
| | - Do Hoon Kim
- R&D Center, Dongkook Pharm. Co., Ltd., Gyeonggi 16229, Korea.
| | - Yu Hwa Park
- R&D Center, Dongkook Pharm. Co., Ltd., Gyeonggi 16229, Korea.
| | - Seung Hyun Kim
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Korea.
| | - In Seok Moon
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 03722, Korea.
| | - Se-Young Choung
- Department of Preventive Pharmacy and Toxicology, College of Pharmacy, Kyung Hee University, Seoul 02453, Korea.
| | - Bin Na Hong
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
| | - Kwang Won Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 21936, Korea.
| | - Tong Ho Kang
- Department of Oriental Medicine Biotechnology, College of Life Sciences and Graduate School of Biotechnology, Kyung Hee University, Global Campus, Gyeonggi 17104, Korea.
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223
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Abstract
INTRODUCTION Sound is integral to communication and connects us to the world through speech and music. Cochlear hair cells are essential for converting sounds into neural impulses. However, these cells are highly susceptible to damage from an array of factors, resulting in degeneration and ultimately irreversible hearing loss in humans. Since the discovery of hair cell regeneration in birds, there have been tremendous efforts to identify therapies that could promote hair cell regeneration in mammals. AREAS COVERED Here, we will review recent studies describing spontaneous hair cell regeneration and direct cellular reprograming as well as other factors that mediate mammalian hair cell regeneration. EXPERT OPINION Numerous combinatorial approaches have successfully reprogrammed non-sensory supporting cells to form hair cells, albeit with limited efficacy and maturation. Studies on epigenetic regulation and transcriptional network of hair cell progenitors may accelerate discovery of more promising reprogramming regimens.
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Affiliation(s)
- Patrick J Atkinson
- a Department of Otolaryngology-Head and Neck Surgery , Stanford University School of Medicine , Stanford , CA , USA
| | - Grace S Kim
- a Department of Otolaryngology-Head and Neck Surgery , Stanford University School of Medicine , Stanford , CA , USA
| | - Alan G Cheng
- a Department of Otolaryngology-Head and Neck Surgery , Stanford University School of Medicine , Stanford , CA , USA
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224
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Fík Z, Bouček J. Inner ear disorders. Cas Lek Cesk 2019; 158:216-220. [PMID: 31931577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Auditory part of the inner ear transforms mechanic energy to the electric energy. The key component of this process are hair cells, which damage leads to often irreversible hearing impairment. The damage can occur due to several external and internal causes and the treatment focuses mainly onto the mitigation of the consequences. Sometimes sensorineural hearing loss can be symptom of some severe disease and thus it can lead to its early diagnosis.
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225
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Pickett SB, Thomas ED, Sebe JY, Linbo T, Esterberg R, Hailey DW, Raible DW. Cumulative mitochondrial activity correlates with ototoxin susceptibility in zebrafish mechanosensory hair cells. eLife 2018; 7:38062. [PMID: 30596476 PMCID: PMC6345563 DOI: 10.7554/elife.38062] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 12/31/2018] [Indexed: 12/11/2022] Open
Abstract
Mitochondria play a prominent role in mechanosensory hair cell damage and death. Although hair cells are thought to be energetically demanding cells, how mitochondria respond to these demands and how this might relate to cell death is largely unexplored. Using genetically encoded indicators, we found that mitochondrial calcium flux and oxidation are regulated by mechanotransduction and demonstrate that hair cell activity has both acute and long-term consequences on mitochondrial function. We tested whether variation in mitochondrial activity reflected differences in the vulnerability of hair cells to the toxic drug neomycin. We observed that susceptibility did not correspond to the acute level of mitochondrial activity but rather to the cumulative history of that activity.
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Affiliation(s)
- Sarah B Pickett
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States
| | - Eric D Thomas
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States
| | - Joy Y Sebe
- Department of Biological Structure, University of Washington, Seattle, United States
| | - Tor Linbo
- Department of Biological Structure, University of Washington, Seattle, United States
| | - Robert Esterberg
- Department of Biological Structure, University of Washington, Seattle, United States.,Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, United States
| | - Dale W Hailey
- Department of Biological Structure, University of Washington, Seattle, United States.,Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, United States
| | - David W Raible
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States.,Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, United States
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226
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Rossetto M. The role of the cupola in the static and dynamic functioning of a lateral line stitch: natures non-linear application of Hooke's law. Commun Integr Biol 2018; 11:e1542256. [PMID: 30574265 PMCID: PMC6300089 DOI: 10.1080/19420889.2018.1542256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/24/2018] [Indexed: 11/23/2022] Open
Abstract
The cupola of a lateral line stitch, once thought to simply be a large surface on which to collect vibrations, is now seen to be key for setting up a non-linear embodiment of Hooke’s law. By coupling, through the cupola, oppositely polarized hair cells in a primitive bilateral symmetry, a non-linear response dependence on input magnitude emerges. This non-linear response, which makes the transduction sensitivity a function of the mechanical input signal’s magnitude, engenders a new understanding of the vast, dynamic range of hair cells.
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227
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Blanco-Sánchez B, Clément A, Fierro J, Stednitz S, Phillips JB, Wegner J, Panlilio JM, Peirce JL, Washbourne P, Westerfield M. Grxcr1 Promotes Hair Bundle Development by Destabilizing the Physical Interaction between Harmonin and Sans Usher Syndrome Proteins. Cell Rep 2018; 25:1281-1291.e4. [PMID: 30380418 PMCID: PMC6284068 DOI: 10.1016/j.celrep.2018.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 08/11/2018] [Accepted: 09/28/2018] [Indexed: 01/02/2023] Open
Abstract
Morphogenesis and mechanoelectrical transduction of the hair cell mechanoreceptor depend on the correct assembly of Usher syndrome (USH) proteins into highly organized macromolecular complexes. Defects in these proteins lead to deafness and vestibular areflexia in USH patients. Mutations in a non-USH protein, glutaredoxin domain-containing cysteine-rich 1 (GRXCR1), cause non-syndromic sensorineural deafness. To understand the deglutathionylating enzyme function of GRXCR1 in deafness, we generated two grxcr1 zebrafish mutant alleles. We found that hair bundles are thinner in homozygous grxcr1 mutants, similar to the USH1 mutants ush1c (Harmonin) and ush1ga (Sans). In vitro assays showed that glutathionylation promotes the interaction between Ush1c and Ush1ga and that Grxcr1 regulates mechanoreceptor development by preventing physical interaction between these proteins without affecting the assembly of another USH1 protein complex, the Ush1c-Cadherin23-Myosin7aa tripartite complex. By elucidating the molecular mechanism through which Grxcr1 functions, we also identify a mechanism that dynamically regulates the formation of Usher protein complexes.
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Affiliation(s)
| | - Aurélie Clément
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Javier Fierro
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Sarah Stednitz
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Jeremy Wegner
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Judy L Peirce
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Philip Washbourne
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
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228
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Dong W, Xia A, Raphael PD, Puria S, Applegate B, Oghalai JS. Organ of Corti vibration within the intact gerbil cochlea measured by volumetric optical coherence tomography and vibrometry. J Neurophysiol 2018; 120:2847-2857. [PMID: 30281386 DOI: 10.1152/jn.00702.2017] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
There is indirect evidence that the mammalian cochlea in the low-frequency apical and the more commonly studied high-frequency basal regions function in fundamentally different ways. Here, we directly tested this hypothesis by measuring sound-induced vibrations of the organ of Corti (OoC) at three turns of the gerbil cochlea using volumetric optical coherence tomography vibrometry (VOCTV), an approach that permits noninvasive imaging through the bone. In the apical turn, there was little frequency selectivity, and the displacement-vs.-frequency curves had low-pass filter characteristics with a corner frequency of ~0.5-0.9 kHz. The vibratory magnitudes increased compressively with increasing stimulus intensity at all frequencies. In the middle turn, responses were similar except for a slight peak in the response at ~2.5 kHz. The gain was ~50 dB at the peak and 30-40 dB at lower frequencies. In the basal turn, responses were sharply tuned and compressively nonlinear, consistent with observations in the literature. These data demonstrated that there is a transition of the mechanical response of the OoC along the length of the cochlea such that frequency tuning is sharper in the base than in the apex. Because the responses are fundamentally different, it is not appropriate to simply frequency shift vibratory data measured at one cochlear location to predict the cochlear responses at other locations. Furthermore, this means that the number of hair cells stimulated by sound is larger for low-frequency stimuli and smaller for high-frequency stimuli for the same intensity level. Thus the mechanisms of central processing of sounds must vary with frequency. NEW & NOTEWORTHY A volumetric optical coherence tomography and vibrometry system was used to probe cochlear mechanics within the intact gerbil cochlea. We found a gradual transition of the mechanical response of the organ of Corti along the length of the cochlea such that tuning at the base is dramatically sharper than that at the apex. These data help to explain discrepancies in the literature regarding how the cochlea processes low-frequency sounds.
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Affiliation(s)
- Wei Dong
- VA Loma Linda Healthcare System, Loma Linda, California.,Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health , Loma Linda, California
| | - Anping Xia
- Department of Otolaryngology - Head and Neck Surgery, Stanford University , Stanford, California
| | - Patrick D Raphael
- Department of Otolaryngology - Head and Neck Surgery, Stanford University , Stanford, California
| | - Sunil Puria
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary and Harvard Medical School , Boston, Massachusetts
| | - Brian Applegate
- Department of Biomedical Engineering, Texas A&M University , College Station, Texas
| | - John S Oghalai
- Caruso Department of Otolaryngology - Head and Neck Surgery, University of Southern California , Los Angeles, California
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229
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Liu X, Zhao M, Xie Y, Li P, Wang O, Zhou B, Yang L, Nie Y, Cheng L, Song X, Jin C, Han F. Null Mutation of the Fascin2 Gene by TALEN Leading to Progressive Hearing Loss and Retinal Degeneration in C57BL/6J Mice. G3 (Bethesda) 2018; 8:3221-30. [PMID: 30082328 DOI: 10.1534/g3.118.200405] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fascin2 (FSCN2) is an actin cross-linking protein that is mainly localized in retinas and in the stereocilia of hair cells. Earlier studies showed that a deletion mutation in human FASCIN2 (FSCN2) gene could cause autosomal dominant retinitis pigmentosa. Recent studies have indicated that a missense mutation in mouse Fscn2 gene (R109H) can contribute to the early onset of hearing loss in DBA/2J mice. To explore the function of the gene, Fscn2 was knocked out using TALEN (transcription activator-like effector nucleases) on the C57BL/6J background. Four mouse strains with deletions of 1, 4, 5, and 41 nucleotides in the target region of Fscn2 were developed. F1 heterozygous (Fscn2+/- ) mice carrying the same deletion of 41 nucleotides were mated to generate the Fscn2-/- mice. As a result, the Fscn2-/- mice showed progressive hearing loss, as measured in the elevation of auditory brainstem-response thresholds. The hearing impairment began at age 3 weeks at high-stimulus frequencies and became most severe at age 24 weeks. Moreover, degeneration of hair cells and loss of stereocilia were remarkable in Fscn2-/- mice, as revealed by F-actin staining and scanning electron microscopy. Furthermore, compared to the controls, the Fscn2-/- mice displayed significantly lower electroretinogram amplitudes and thinner retinas at 8, 16, and 24 weeks. These results demonstrate that, in C57BL/6Jmice, Fscn2 is essential for maintaining ear and eye function and that a null mutation of Fscn2 leads to progressive hearing loss and retinal degeneration.
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230
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Abstract
Inner hair cells (IHCs) and outer hair cells (OHCs) are the two anatomically and functionally distinct types of mechanosensitive receptor cells in the mammalian cochlea. The molecular mechanisms defining their morphological and functional specializations are largely unclear. As a first step to uncover the underlying mechanisms, we examined the transcriptomes of IHCs and OHCs isolated from adult CBA/J mouse cochleae. One thousand IHCs and OHCs were separately collected using the suction pipette technique. RNA sequencing of IHCs and OHCs was performed and their transcriptomes were analyzed. The results were validated by comparing some IHC and OHC preferentially expressed genes between present study and published microarray-based data as well as by real-time qPCR. Antibody-based immunocytochemistry was used to validate preferential expression of SLC7A14 and DNM3 in IHCs and OHCs. These data are expected to serve as a highly valuable resource for unraveling the molecular mechanisms underlying different biological properties of IHCs and OHCs as well as to provide a road map for future characterization of genes expressed in IHCs and OHCs.
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Affiliation(s)
- Yi Li
- Department of Otorhinolaryngology, Beijing Tongren Hospital, Beijing Capital Medical University, Beijing 100730, China
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska 68170, USA
| | - Huizhan Liu
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska 68170, USA
| | - Kimberlee P. Giffen
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska 68170, USA
| | - Lei Chen
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska 68170, USA
- Chongqing Academy of Animal Science, Chongqing 402460, China
| | - Kirk W. Beisel
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska 68170, USA
| | - David Z. Z. He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska 68170, USA
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231
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Liu H, Chen L, Giffen KP, Stringham ST, Li Y, Judge PD, Beisel KW, He DZZ. Cell-Specific Transcriptome Analysis Shows That Adult Pillar and Deiters' Cells Express Genes Encoding Machinery for Specializations of Cochlear Hair Cells. Front Mol Neurosci 2018; 11:356. [PMID: 30327589 PMCID: PMC6174830 DOI: 10.3389/fnmol.2018.00356] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 09/11/2018] [Indexed: 11/13/2022] Open
Abstract
The mammalian auditory sensory epithelium, the organ of Corti, is composed of hair cells and supporting cells. Hair cells contain specializations in the apical, basolateral and synaptic membranes. These specializations mediate mechanotransduction, electrical and mechanical activities and synaptic transmission. Supporting cells maintain homeostasis of the ionic and chemical environment of the cochlea and contribute to the stiffness of the cochlear partition. While spontaneous proliferation and transdifferentiation of supporting cells are the source of the regenerative response to replace lost hair cells in lower vertebrates, supporting cells in adult mammals no longer retain that capability. An important first step to revealing the basic biological properties of supporting cells is to characterize their cell-type specific transcriptomes. Using RNA-seq, we examined the transcriptomes of 1,000 pillar and 1,000 Deiters' cells, as well as the two types of hair cells, individually collected from adult CBA/J mouse cochleae using a suction pipette technique. Our goal was to determine whether pillar and Deiters' cells, the commonly targeted cells for hair cell replacement, express the genes known for encoding machinery for hair cell specializations in the apical, basolateral, and synaptic membranes. We showed that both pillar and Deiters' cells express these genes, with pillar cells being more similar to hair cells than Deiters' cells. The fact that adult pillar and Deiters' cells express the genes cognate to hair cell specializations provides a strong molecular basis for targeting these cells for mammalian hair cell replacement after hair cells are lost due to damage.
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Affiliation(s)
- Huizhan Liu
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
| | - Lei Chen
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States.,Chongqing Academy of Animal Science, Chongqing, China
| | - Kimberlee P Giffen
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
| | - Sean T Stringham
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
| | - Yi Li
- Department of Otorhinolaryngology-Head and Neck Surgery, Beijing Tonren Hospital, Capital Medical University, Beijing, China
| | - Paul D Judge
- Department of Otolaryngology-Head and Neck Surgery, University of Nebraska Medical Center, Omaha, NE, United States
| | - Kirk W Beisel
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
| | - David Z Z He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
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232
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Hu Q, Guo L, Li J, Song C, Yu L, He DZZ, Xiong W. Deletion of Kncn Does Not Affect Kinocilium and Stereocilia Bundle Morphogenesis and Mechanotransduction in Cochlear Hair Cells. Front Mol Neurosci 2018; 11:326. [PMID: 30254566 PMCID: PMC6141681 DOI: 10.3389/fnmol.2018.00326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/23/2018] [Indexed: 11/13/2022] Open
Abstract
Auditory hair cells possess stunning cilia structure that composes of a bundle of stereocilia for mechano-electrical transduction and a single kinocilium for guiding the polarity of hair bundle towards maturation. However, the molecules underlying kinocilium function have not yet been fully understood. Hence, the proteins involved in hair bundle development and function are of a large interest. From a fine microarray analysis, we found that kinocilin (Kncn) was enriched in hair cell specific expression profile. Consistently, it has been reported that KNCN was a protein mainly located in the kinocilium of hair cells in the inner ear. However, the hypothesis that KNCN is a kinocilium protein has not been validated in mice with Kncn gene perturbed. In this study, we generated Kncn knockout mouse lines by CRISPR/Cas9 technique and further examined the morphology and function of cochlear hair cells. Our results showed that there was no obvious hearing loss in the knockout mice, determined by audiometry. Histological study demonstrated that the inner ear and hair cell structure were intact. Especially, there was no deficit of mechanotransduction (MET) in cochlear outer hair cells (OHCs). In summary, our work suggests that KNCN is not essential for kinocilium-oriented hair bundle function in cochlear hair cells.
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Affiliation(s)
- Qun Hu
- Tsinghua-IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Li Guo
- Department of Otolaryngology, Peking University People's Hospital, Beijing, China
| | - Jie Li
- Tsinghua-IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Chenmeng Song
- Tsinghua-IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lisheng Yu
- Department of Otolaryngology, Peking University People's Hospital, Beijing, China
| | - David Z Z He
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States
| | - Wei Xiong
- Tsinghua-IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
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233
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Wilkerson BA, Artoni F, Lea C, Ritchie K, Ray CA, Bermingham-McDonogh O. Effects of 3,3'-Iminodipropionitrile on Hair Cell Numbers in Cristae of CBA/CaJ and C57BL/6J Mice. J Assoc Res Otolaryngol 2018; 19:483-491. [PMID: 30171385 DOI: 10.1007/s10162-018-00687-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 06/25/2018] [Indexed: 12/12/2022] Open
Abstract
This study examines absolute hair cell numbers in the cristae of C57BL/6J mice and CBA/CaJ mice from weaning to adulthood as well as the dose required for 3,3'-iminodiproprionitrile (IDPN)-injury of the cristae in C57BL/6J mice and CBA/CaJ mice, the two mouse strains most commonly used by inner ear researchers. In cristae of CBA/CaJ and C57BL/6J mice, no loss of hair cells was observed up to 24 weeks. In both strains, dose-dependent loss of hair cells was observed 7 days after IDPN treatment of 2-month-old mice (IC50 = 16.1 mmol/kg in C57BL/6J mice vs. 25.21 mmol/kg in CBA/CaJ mice). Four-month-old C57BL/6J mice exposed to IDPN developed dose-dependent vestibular dysfunction as indicated by increased activity and circling behavior in open field tests and by failure to swim 7 days after treatment. IDPN-hair cell injury in C57BL/6J mice and CBA/CaJ mice represents a fast and predictable experimental model for the study of vestibular degeneration and a platform for the testing of vestibular therapies.
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Affiliation(s)
- Brent A Wilkerson
- Department of Biological Structure, University of Washington, 1959 NE Pacific St., Box 357420, Seattle, WA, 98195, USA.,Institute for Stem Cells and Regenerative Medicine, University of Washington, Seattle, Washington, 98109, USA
| | - Filippo Artoni
- Department of Biological Structure, University of Washington, 1959 NE Pacific St., Box 357420, Seattle, WA, 98195, USA.,Institute for Stem Cells and Regenerative Medicine, University of Washington, Seattle, Washington, 98109, USA
| | - Colby Lea
- Department of Biological Structure, University of Washington, 1959 NE Pacific St., Box 357420, Seattle, WA, 98195, USA.,Institute for Stem Cells and Regenerative Medicine, University of Washington, Seattle, Washington, 98109, USA
| | - Kayla Ritchie
- Department of Biological Structure, University of Washington, 1959 NE Pacific St., Box 357420, Seattle, WA, 98195, USA.,Institute for Stem Cells and Regenerative Medicine, University of Washington, Seattle, Washington, 98109, USA
| | - Catherine A Ray
- Department of Biological Structure, University of Washington, 1959 NE Pacific St., Box 357420, Seattle, WA, 98195, USA.,Institute for Stem Cells and Regenerative Medicine, University of Washington, Seattle, Washington, 98109, USA
| | - Olivia Bermingham-McDonogh
- Department of Biological Structure, University of Washington, 1959 NE Pacific St., Box 357420, Seattle, WA, 98195, USA. .,Institute for Stem Cells and Regenerative Medicine, University of Washington, Seattle, Washington, 98109, USA.
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234
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Uribe PM, Villapando BK, Lawton KJ, Fang Z, Gritsenko D, Bhandiwad A, Sisneros JA, Xu J, Coffin AB. Larval Zebrafish Lateral Line as a Model for Acoustic Trauma. eNeuro 2018; 5:ENEURO. [PMID: 30225343 DOI: 10.1523/ENEURO.0206-18.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/25/2018] [Accepted: 08/08/2018] [Indexed: 12/14/2022] Open
Abstract
Excessive noise exposure damages sensory hair cells, leading to permanent hearing loss. Zebrafish are a highly tractable model that have advanced our understanding of drug-induced hair cell death, yet no comparable model exists for noise exposure research. We demonstrate the utility of zebrafish as model to increase understanding of hair cell damage from acoustic trauma and develop protective therapies. We created an acoustic trauma system using underwater cavitation to stimulate lateral line hair cells. We found that acoustic stimulation resulted in exposure time- and intensity-dependent lateral line and saccular hair cell damage that is maximal at 48–72 h post-trauma. The number of TUNEL+ lateral line hair cells increased 72 h post-exposure, whereas no increase was observed in TUNEL+ supporting cells, demonstrating that acoustic stimulation causes hair cell-specific damage. Lateral line hair cells damaged by acoustic stimulation regenerate within 3 d, consistent with prior regeneration studies utilizing ototoxic drugs. Acoustic stimulation-induced hair cell damage is attenuated by pharmacological inhibition of protein synthesis or caspase activation, suggesting a requirement for translation and activation of apoptotic signaling cascades. Surviving hair cells exposed to acoustic stimulation showed signs of synaptopathy, consistent with mammalian studies. Finally, we demonstrate the feasibility of this platform to identify compounds that prevent acoustic trauma by screening a small redox library for protective compounds. Our data suggest that acoustic stimulation results in lateral line hair cell damage consistent with acoustic trauma research in mammals, providing a highly tractable model for high-throughput genetic and drug discovery studies.
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235
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Sun S, Babola T, Pregernig G, So KS, Nguyen M, Su SSM, Palermo AT, Bergles DE, Burns JC, Müller U. Hair Cell Mechanotransduction Regulates Spontaneous Activity and Spiral Ganglion Subtype Specification in the Auditory System. Cell 2018; 174:1247-1263.e15. [PMID: 30078710 PMCID: PMC6429032 DOI: 10.1016/j.cell.2018.07.008] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/23/2018] [Accepted: 07/02/2018] [Indexed: 01/06/2023]
Abstract
Type I spiral ganglion neurons (SGNs) transmit sound information from cochlear hair cells to the CNS. Using transcriptome analysis of thousands of single neurons, we demonstrate that murine type I SGNs consist of subclasses that are defined by the expression of subsets of transcription factors, cell adhesion molecules, ion channels, and neurotransmitter receptors. Subtype specification is initiated prior to the onset of hearing during the time period when auditory circuits mature. Gene mutations linked to deafness that disrupt hair cell mechanotransduction or glutamatergic signaling perturb the firing behavior of SGNs prior to hearing onset and disrupt SGN subtype specification. We thus conclude that an intact hair cell mechanotransduction machinery is critical during the pre-hearing period to regulate the firing behavior of SGNs and their segregation into subtypes. Because deafness is frequently caused by defects in hair cells, our findings have significant ramifications for the etiology of hearing loss and its treatment.
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Affiliation(s)
- Shuohao Sun
- The Solomon Snyder Department of Neuroscience and Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Travis Babola
- The Solomon Snyder Department of Neuroscience and Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Gabriela Pregernig
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Kathy S So
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Matthew Nguyen
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Shin-San M Su
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Adam T Palermo
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Dwight E Bergles
- The Solomon Snyder Department of Neuroscience and Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Joseph C Burns
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA.
| | - Ulrich Müller
- The Solomon Snyder Department of Neuroscience and Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
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236
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Ge J, Elferich J, Goehring A, Zhao H, Schuck P, Gouaux E. Structure of mouse protocadherin 15 of the stereocilia tip link in complex with LHFPL5. eLife 2018; 7:38770. [PMID: 30070639 PMCID: PMC6092121 DOI: 10.7554/elife.38770] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/31/2018] [Indexed: 11/13/2022] Open
Abstract
Hearing and balance involve the transduction of mechanical stimuli into electrical signals by deflection of bundles of stereocilia linked together by protocadherin 15 (PCDH15) and cadherin 23 'tip links'. PCDH15 transduces tip link tension into opening of a mechano-electrical transduction (MET) ion channel. PCDH15 also interacts with LHFPL5, a candidate subunit of the MET channel. Here we illuminate the PCDH15-LHFPL5 structure, showing how the complex is composed of PCDH15 and LHFPL5 subunit pairs related by a 2-fold axis. The extracellular cadherin domains define a mobile tether coupled to a rigid, 2-fold symmetric 'collar' proximal to the membrane bilayer. LHFPL5 forms extensive interactions with the PCDH15 transmembrane helices and stabilizes the overall PCDH15-LHFPL5 assembly. Our studies illuminate the architecture of the PCDH15-LHFPL5 complex, localize mutations associated with deafness, and shed new light on how forces in the PCDH15 tether may be transduced into the stereocilia membrane.
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Affiliation(s)
- Jingpeng Ge
- Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Johannes Elferich
- Vollum Institute, Oregon Health & Science University, Portland, United States
| | - April Goehring
- Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Huaying Zhao
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
| | - Peter Schuck
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
| | - Eric Gouaux
- Vollum Institute, Oregon Health & Science University, Portland, United States.,Howard Hughes Medical Institute, Oregon Health & Science University, Portland, United States
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237
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Dionne G, Qiu X, Rapp M, Liang X, Zhao B, Peng G, Katsamba PS, Ahlsen G, Rubinstein R, Potter CS, Carragher B, Honig B, Müller U, Shapiro L. Mechanotransduction by PCDH15 Relies on a Novel cis-Dimeric Architecture. Neuron 2018; 99:480-492.e5. [PMID: 30057206 DOI: 10.1016/j.neuron.2018.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 06/06/2018] [Accepted: 06/29/2018] [Indexed: 10/28/2022]
Abstract
The tip link, a filament formed by protocadherin 15 (PCDH15) and cadherin 23, conveys mechanical force from sound waves and head movement to open hair-cell mechanotransduction channels. Tip-link cadherins are thought to have acquired structural features critical for their role in mechanotransduction. Here, we biophysically and structurally characterize the unusual cis-homodimeric architecture of PCDH15. We show that PCDH15 molecules form double-helical assemblies through cis-dimerization interfaces in the extracellular cadherin EC2-EC3 domain region and in a unique membrane-proximal domain. Electron microscopy studies visualize the cis-dimeric PCDH15 assembly and reveal the PCDH15 extracellular domain as a parallel double helix with cis cross-bridges at the two locations we defined. The helical configuration suggests the potential for elasticity through helix winding and unwinding. Functional studies in hair cells show that mutations that perturb PCDH15 dimerization contacts affect mechanotransduction. Together, these data reveal the cis-dimeric architecture of PCDH15 and show that dimerization is critical for sensing mechanical stimuli.
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Affiliation(s)
- Gilman Dionne
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Micah Rapp
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Xiaoping Liang
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bo Zhao
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Guihong Peng
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Phinikoula S Katsamba
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Goran Ahlsen
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Rotem Rubinstein
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - Clinton S Potter
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Bridget Carragher
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Barry Honig
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA.
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA.
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238
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Harley RJ, Murdy JP, Wang Z, Kelly MC, Ropp TJF, Park SH, Maness PF, Manis PB, Coate TM. Neuronal cell adhesion molecule (NrCAM) is expressed by sensory cells in the cochlea and is necessary for proper cochlear innervation and sensory domain patterning during development. Dev Dyn 2018; 247:934-950. [PMID: 29536590 PMCID: PMC6105381 DOI: 10.1002/dvdy.24629] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 03/06/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND In the cochlea, auditory development depends on precise patterns of innervation by afferent and efferent nerve fibers, as well as a stereotyped arrangement of hair and supporting cells. Neuronal cell adhesion molecule (NrCAM) is a homophilic cell adhesion molecule that controls diverse aspects of nervous system development, but the function of NrCAM in cochlear development is not well understood. RESULTS Throughout cochlear innervation, NrCAM is detectable on spiral ganglion neuron (SGN) afferent and olivocochlear efferent fibers, and on the membranes of developing hair and supporting cells. Neonatal Nrcam-null cochleae show errors in type II SGN fasciculation, reduced efferent innervation, and defects in the stereotyped packing of hair and supporting cells. Nrcam loss also leads to dramatic changes in the profiles of presynaptic afferent and efferent synaptic markers at the time of hearing onset. Despite these numerous developmental defects, Nrcam-null adults do not show defects in auditory acuity, and by postnatal day 21, the developmental deficits in ribbon synapse distribution and sensory domain structure appear to have been corrected. CONCLUSIONS NrCAM is expressed by several neural and sensory epithelial subtypes within the developing cochlea, and the loss of Nrcam confers numerous, but nonpermanent, developmental defects in innervation and sensory domain patterning. Developmental Dynamics 247:934-950, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Randall J. Harley
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Joseph P. Murdy
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Zhirong Wang
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Michael C. Kelly
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, 35 Convent Dr., Bethesda, MD 20892, USA
| | - Tessa-Jonne F. Ropp
- Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel Hill, B251 Marsico Hall, CB#7070, 125 Mason Farm Rd., Chapel Hill, NC 27599, USA
| | - SeHoon H. Park
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Patricia F. Maness
- Department of Biochemistry and Biophysics, The University of North Carolina School of Medicine, 120 Mason Farm Rd., suite 3020, CB#7260, Chapel Hill, NC 27599, USA
| | - Paul B. Manis
- Department of Otolaryngology/Head and Neck Surgery and Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, B027 Marsico Hall, CB#7070. 125 Mason Farm Rd., Chapel Hill, NC 27599
| | - Thomas M. Coate
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
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239
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Dow E, Jacobo A, Hossain S, Siletti K, Hudspeth AJ. Connectomics of the zebrafish's lateral-line neuromast reveals wiring and miswiring in a simple microcircuit. eLife 2018; 7:33988. [PMID: 29893686 PMCID: PMC5997450 DOI: 10.7554/elife.33988] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/10/2018] [Indexed: 12/02/2022] Open
Abstract
The lateral-line neuromast of the zebrafish displays a restricted, consistent pattern of innervation that facilitates the comparison of microcircuits across individuals, developmental stages, and genotypes. We used serial blockface scanning electron microscopy to determine from multiple specimens the neuromast connectome, a comprehensive set of connections between hair cells and afferent and efferent nerve fibers. This analysis delineated a complex but consistent wiring pattern with three striking characteristics: each nerve terminal is highly specific in receiving innervation from hair cells of a single directional sensitivity; the innervation is redundant; and the terminals manifest a hierarchy of dominance. Mutation of the canonical planar-cell-polarity gene vangl2, which decouples the asymmetric phenotypes of sibling hair-cell pairs, results in randomly positioned, randomly oriented sibling cells that nonetheless retain specific wiring. Because larvae that overexpress Notch exhibit uniformly oriented, uniformly innervating hair-cell siblings, wiring specificity is mediated by the Notch signaling pathway.
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Affiliation(s)
- Eliot Dow
- Laboratory of Sensory Neuroscience, Howard Hughes Medical Institute, The Rockefeller University, New York, United States.,Presence Saint Francis Medical Center, Evanston, United States
| | - Adrian Jacobo
- Laboratory of Sensory Neuroscience, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Sajjad Hossain
- Laboratory of Sensory Neuroscience, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Kimberly Siletti
- Laboratory of Sensory Neuroscience, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - A J Hudspeth
- Laboratory of Sensory Neuroscience, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
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240
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Abstract
The sensory organs of the inner ear are challenging to study in mammals due to their inaccessibility to experimental manipulation and optical observation. Moreover, although existing culture techniques allow biochemical perturbations, these methods do not provide a means to study the effects of mechanical force and tissue stiffness during development of the inner ear sensory organs. Here we describe a method for three-dimensional organotypic culture of the intact murine utricle and cochlea that overcomes these limitations. The technique for adjustment of a three-dimensional matrix stiffness described here permits manipulation of the elastic force opposing tissue growth. This method can therefore be used to study the role of mechanical forces during inner ear development. Additionally, the cultures permit virus-mediated gene delivery, which can be used for gain- and loss-of-function experiments. This culture method preserves innate hair cells and supporting cells and serves as a potentially superior alternative to the traditional two-dimensional culture of vestibular and auditory sensory organs.
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Affiliation(s)
- Ksenia Gnedeva
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California; Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California;
| | - A J Hudspeth
- Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, The Rockefeller University
| | - Neil Segil
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of the University of Southern California; Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California
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241
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Lin LY, Yeh YH, Hung GY, Lin CH, Hwang PP, Horng JL. Role of Calcium-Sensing Receptor in Mechanotransducer-Channel-Mediated Ca 2+ Influx in Hair Cells of Zebrafish Larvae. Front Physiol 2018; 9:649. [PMID: 29899708 PMCID: PMC5988855 DOI: 10.3389/fphys.2018.00649] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 05/14/2018] [Indexed: 01/16/2023] Open
Abstract
The calcium-sensing receptor (CaSR) is an extracellular Ca2+ sensor that plays a critical role in maintaining Ca2+ homeostasis in several organs, including the parathyroid gland and kidneys. In this study, through in situ hybridization, the expression of CaSR mRNA was found in the neuromasts of zebrafish larvae. Immunohistochemistry further demonstrated that the CaSR protein was present in neuromast hair cell stereocilia and basolateral membranes. Based on the expression and subcellular localization of the CaSR in hair cells, we hypothesized that the CaSR is expressed in zebrafish lateral-line hair cells to regulate mechanotransducer (MET)-channel-mediated Ca2+ entry. Using the scanning ion-selective electrode technique, MET-channel-mediated Ca2+ influx at the stereocilia of hair cells was measured in intact larvae. Ca2+ influx was suppressed after larvae were pretreated with a CaSR activator (R-568) or high-Ca2+ (HCa) medium. Gene knockdown by using morpholino oligonucleotides decreased CaSR expression in hair cells and eliminated the effects of R-568 and HCa on Ca2+ influx. In addition, we found that treatment with R-568 attenuated neomycin-induced hair cell death. This study is the first to demonstrate that the CaSR is involved in mechanotransduction in zebrafish hair cells.
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Affiliation(s)
- Li-Yih Lin
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ya-Hsin Yeh
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Giun-Yi Hung
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan.,Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Pediatrics, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chia-Hao Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.,Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Jiun-Lin Horng
- Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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242
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Zhang Y, Guo L, Lu X, Cheng C, Sun S, Li W, Zhao L, Lai C, Zhang S, Yu C, Tang M, Chen Y, Chai R, Li H. Characterization of Lgr6+ Cells as an Enriched Population of Hair Cell Progenitors Compared to Lgr5+ Cells for Hair Cell Generation in the Neonatal Mouse Cochlea. Front Mol Neurosci 2018; 11:147. [PMID: 29867341 PMCID: PMC5961437 DOI: 10.3389/fnmol.2018.00147] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/12/2018] [Indexed: 12/20/2022] Open
Abstract
Hair cell (HC) loss is irreversible because only very limited HC regeneration has been observed in the adult mammalian cochlea. Wnt/β-catenin signaling regulates prosensory cell proliferation and differentiation during cochlear development, and Wnt activation promotes the proliferation of Lgr5+ cochlear HC progenitors in newborn mice. Similar to Lgr5, Lgr6 is also a Wnt downstream target gene. Lgr6 is reported to be present in adult stem cells in the skin, nail, tongue, lung, and mammary gland, and this protein is very important for adult stem cell maintenance in rapidly proliferating organs. Our previous studies showed that Lgr6+ cells are a subpopulation of Lgr5+ progenitor cells and that both Lgr6+ and Lgr5+ progenitors can generate Myosin7a+ HCs in vitro. Thus we hypothesized that Lgr6+ cells are an enriched population of cochlear progenitor cells. However, the detailed distinctions between the Lgr5+ and Lgr6+ progenitors are unclear. Here, we systematically compared the proliferation, HC differentiation, and detailed transcriptome expression profiles of these two progenitor populations. We found that the same number of isolated Lgr6+ progenitors generated significantly more Myosin7a+ HCs compared to Lgr5+ progenitors; however, Lgr5+ progenitors formed more epithelial colonies and more spheres than Lgr6+ progenitors in vitro. Using RNA-Seq, we compared the transcriptome differences between Lgr5+ and Lgr6+ progenitors and identified a list of significantly differential expressed genes that might regulate the proliferation and differentiation of these HC progenitors, including 4 cell cycle genes, 9 cell signaling pathway genes, and 54 transcription factors. In conclusion, we demonstrate that Lgr6+ progenitors are an enriched population of inner ear progenitors that generate more HCs compared to Lgr5+ progenitors in the newborn mouse cochlea, and the our research provides a series of genes that might regulate the proliferation of progenitors and HC generation.
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Affiliation(s)
- Yanping Zhang
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Xiaoling Lu
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Cheng Cheng
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Shan Sun
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Wen Li
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Liping Zhao
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Chuijin Lai
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Chenjie Yu
- Department of Otolaryngology Head and Neck Surgery, Jiangsu Provincial Key Medical Discipline Laboratory, Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Yan Chen
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.,Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine, National Health and Family Planning Commission (NHFPC), Shanghai, China.,Shanghai Engineering Research Center of Cochlear Implant, Shanghai, China.,The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China
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243
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Abstract
Hair cells in the inner ear convert mechanical stimuli provided by sound waves and head movements into electrical signal. Several mechanically evoked ionic currents with different properties have been recorded in hair cells. The search for the proteins that form the underlying ion channels is still in progress. The mechanoelectrical transduction (MET) channel near the tips of stereociliary in hair cells, which is responsible for sensory transduction, has been studied most extensively. Several components of the sensory mechanotransduction machinery in stereocilia have been identified, including the multi-transmembrane proteins tetraspan membrane protein in hair cell stereocilia (TMHS)/LHFPL5, transmembrane inner ear (TMIE) and transmembrane channel-like proteins 1 and 2 (TMC1/2). However, there remains considerable uncertainty regarding the molecules that form the channel pore. In addition to the sensory MET channel, hair cells express the mechanically gated ion channel PIEZO2, which is localized near the base of stereocilia and not essential for sensory transduction. The function of PIEZO2 in hair cells is not entirely clear but it might have a role in damage sensing and repair processes. Additional stretch-activated channels of unknown molecular identity and function have been found to localize at the basolateral membrane of hair cells. Here, we review current knowledge regarding the different mechanically gated ion channels in hair cells and discuss open questions concerning their molecular composition and function.
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Affiliation(s)
- Xufeng Qiu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ulrich Müller
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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244
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Abstract
The utricle provides the vestibular reflex pathways with the sensory codes of inertial acceleration of self-motion and head orientation with respect to gravity to control balance and equilibrium. Here we present an anatomical description of this structure in the adult oyster toadfish and establish a morphological basis for interpretation of subsequent functional studies. Light, scanning, and transmission electron microscopy techniques were applied to visualize the sensory epithelium at varying levels of detail, its neural innervation and its synaptic organization. Scanning electron microscopy was used to visualize otolith mass and morphological polarization patterns of hair cells. Afferent nerve fibers were visualized following labeling with biocytin, and light microscope images were used to make three-dimensional (3-D) reconstructions of individual labeled afferents to identify dendritic morphology with respect to epithelial location. Transmission electron micrographs were compiled to create a serial 3-D reconstruction of a labeled afferent over a segment of its dendritic field and to examine the cell-afferent synaptic contacts. Major observations are: a well-defined striola, medial and lateral extra-striolar regions with a zonal organization of hair bundles; prominent lacinia projecting laterally; dependence of hair cell density on macular location; narrow afferent dendritic fields that follow the hair bundle polarization; synaptic specializations issued by afferents are typically directed towards a limited number of 7-13 hair cells, but larger dendritic fields in the medial extra-striola can be associated with > 20 hair cells also; and hair cell synaptic bodies can be confined to only an individual afferent or can synapse upon several afferents.
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Affiliation(s)
- Richard Boyle
- Vestibular Biophysics Laboratory, Ames Research Center, NASA, Moffett Field, California, 94035-1000
| | - Reza Ehsanian
- Vestibular Biophysics Laboratory, Ames Research Center, NASA, Moffett Field, California, 94035-1000
| | - Alireza Mofrad
- Vestibular Biophysics Laboratory, Ames Research Center, NASA, Moffett Field, California, 94035-1000
| | - Yekaterina Popova
- Vestibular Biophysics Laboratory, Ames Research Center, NASA, Moffett Field, California, 94035-1000
| | - Joseph Varelas
- Vestibular Biophysics Laboratory, Ames Research Center, NASA, Moffett Field, California, 94035-1000.,University of California, Santa Cruz, California, 95064
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245
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Guan M, Fang Q, He Z, Li Y, Qian F, Qian X, Lu L, Zhang X, Liu D, Qi J, Zhang S, Tang M, Gao X, Chai R. Inhibition of ARC decreases the survival of HEI-OC-1 cells after neomycin damage in vitro. Oncotarget 2018; 7:66647-66659. [PMID: 27556499 PMCID: PMC5341827 DOI: 10.18632/oncotarget.11336] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/10/2016] [Indexed: 12/17/2022] Open
Abstract
Hearing loss is a common sensory disorder mainly caused by the loss of hair cells (HCs). Noise, aging, and ototoxic drugs can all induce apoptosis in HCs. Apoptosis repressor with caspase recruitment domain(ARC) is a key factor in apoptosis that inhibits both intrinsic and extrinsic apoptosis pathways; however, there have been no reports on the role of ARC in HC loss in the inner ear. In this study, we used House Ear Institute Organ of Corti 1 (HEI-OC-1) cells, which is a cochlear hair-cell-like cell line, to investigate the role of ARC in aminoglycoside-induced HC loss. ARC was expressed in the cochlear HCs as well as in the HEI-OC-1 cells, but not in the supporting cells, and the expression level of ARC in HCs was decreased after neomycin injury in both cochlear HCs and HEI-OC-1 cells, suggesting that reduced levels of ARC might correlate with neomycin-induced HC loss. We inhibited ARC expression using siRNA and found that this significantly increased the sensitivity of HEI-OC-1 cells to neomycin toxicity. Finally, we found that ARC inhibition increased the expression of pro-apoptotic factors, decreased the mitochondrial membrane potential, and increased the level of reactive oxygen species (ROS) after neomycin injury, suggesting that ARC inhibits cell death and apoptosis in HEI-OC-1 cells by controlling mitochondrial function and ROS accumulation. Thus the endogenous anti-apoptotic factor ARC might be a new therapeutic target for the prevention of aminoglycoside-induced HC loss.
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Affiliation(s)
- Ming Guan
- Department of Otolaryngology, The Affiliated Hangzhou Hospital of Nanjing Medical University, Hangzhou 310006, China.,Department of Otolaryngology, Hangzhou First People's Hospital, Hangzhou 310006, China.,Department of Otolaryngology, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing 210008, China
| | - Qiaojun Fang
- MOE Key Laboratory of Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Zuhong He
- MOE Key Laboratory of Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Yong Li
- Department of Otolaryngology, The Affiliated Hangzhou Hospital of Nanjing Medical University, Hangzhou 310006, China.,Department of Otolaryngology, Hangzhou First People's Hospital, Hangzhou 310006, China
| | - Fuping Qian
- MOE Key Laboratory of Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Xiaoyun Qian
- Department of Otolaryngology, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing 210008, China.,Department of Otolaryngology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Ling Lu
- Department of Otolaryngology, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing 210008, China.,Department of Otolaryngology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Xiaoli Zhang
- Department of Otolaryngology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Dingding Liu
- Department of Otolaryngology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Jieyu Qi
- MOE Key Laboratory of Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Shasha Zhang
- MOE Key Laboratory of Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Mingliang Tang
- MOE Key Laboratory of Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Xia Gao
- Department of Otolaryngology, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing 210008, China.,Department of Otolaryngology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Renjie Chai
- MOE Key Laboratory of Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Institute of Life Sciences, Southeast University, Nanjing 210096, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
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246
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Rigon F, Gasparini F, Shimeld SM, Candiani S, Manni L. Developmental signature, synaptic connectivity and neurotransmission are conserved between vertebrate hair cells and tunicate coronal cells. J Comp Neurol 2018; 526:957-971. [PMID: 29277977 DOI: 10.1002/cne.24382] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 11/08/2022]
Abstract
In tunicates, the coronal organ represents a sentinel checking particle entrance into the pharynx. The organ differentiates from an anterior embryonic area considered a proto-placode. For their embryonic origin, morphological features and function, coronal sensory cells have been hypothesized to be homologues to vertebrate hair cells. However, vertebrate hair cells derive from a posterior placode. This contradicts one of the principle historical criteria for homology, similarity of position, which could be taken as evidence against coronal cells/hair cells homology. In the tunicates Ciona intestinalis and C. robusta, we found that the coronal organ expresses genes (Atoh, Notch, Delta-like, Hairy-b, and Musashi) characterizing vertebrate neural and hair cell development. Moreover, coronal cells exhibit a complex synaptic connectivity pattern, and express neurotransmitters (Glu, ACh, GABA, 5-HT, and catecholamines), or enzymes for their synthetic machinery, involved in hair cell activity. Lastly, coronal cells express the Trpa gene, which encodes an ion channel expressed in hair cells. These data lead us to hypothesize a model in which competence to make secondary mechanoreceptors was initially broadly distributed through placode territories, but has become confined to different placodes during the evolution of the vertebrate and tunicate lineages.
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Affiliation(s)
- Francesca Rigon
- Dipartimento di Biologia, Università di Padova, Padova, Italy
| | - Fabio Gasparini
- Dipartimento di Biologia, Università di Padova, Padova, Italy
| | | | - Simona Candiani
- Dipartimento di Scienze della Terra dell'Ambiente e della Vita, Università di Genova, Genova, Italy
| | - Lucia Manni
- Dipartimento di Biologia, Università di Padova, Padova, Italy
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247
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Chen Z, Chou SW, McDermott BM. Ribeye protein is intrinsically dynamic but is stabilized in the context of the ribbon synapse. J Physiol 2018; 596:409-421. [PMID: 29086422 DOI: 10.1113/jp271215] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 10/26/2017] [Indexed: 01/16/2023] Open
Abstract
KEY POINTS The synaptic ribbon is an organelle that coordinates rapid and sustained vesicle release to enable hearing and balance. Ribeye a and b proteins are major constituents of the synaptic ribbon in hair cells. In this study, we use optically clear transgenic zebrafish to examine the potential dynamics of ribeye proteins in vivo. We demonstrate that ribeye proteins are inherently dynamic but are stabilized at the ribbons of hair cells in the ear and the lateral line system. ABSTRACT Ribeye protein is a major constituent of the synaptic ribbon, an organelle that coordinates rapid and sustained vesicle release to enable hearing and balance. The ribbon is considered to be a stable structure. However, under certain physiological conditions such as acoustic overexposure that results in temporary noise-induced hearing loss or perturbations of ion channels, ribbons may change shape or vanish altogether, suggesting greater plasticity than previously appreciated. The dynamic properties of ribeye proteins are unknown. Here we use transgenesis and imaging to explore the behaviours of ribeye proteins within the ribbon and also their intrinsic properties outside the context of the ribbon synapse in a control cell type, the skin cell. By fluorescence recovery after photobleaching (FRAP) on transgenic zebrafish larvae, we test whether ribeye proteins are dynamic in vivo in real time. In the skin, a cell type devoid of synaptic contacts, Ribeye a-mCherry exchanges with ribbon-like structures on a time scale of minutes (t1/2 = 3.2 min). In contrast, Ribeye a of the ear and lateral line and Ribeye b of the lateral line each exchange at ribbons of hair cells an order of magnitude slower (t1/2 of 125.6 min, 107.0 min and 95.3 min, respectively) than Ribeye a of the skin. These basal exchange rates suggest that long-term ribbon presence may require ribeye renewal. Our studies demonstrate that ribeye proteins are inherently dynamic but are stabilized at the ribbons of sensory cells in vivo.
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Affiliation(s)
- Zongwei Chen
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Shih-Wei Chou
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Brian M McDermott
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Neurosciences, Case Western Reserve University, Cleveland, OH, 44106, USA
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248
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Hoffman LF, Choy KR, Sultemeier DR, Simmons DD. Oncomodulin Expression Reveals New Insights into the Cellular Organization of the Murine Utricle Striola. J Assoc Res Otolaryngol 2018; 19:33-51. [PMID: 29318409 DOI: 10.1007/s10162-017-0652-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/18/2017] [Indexed: 01/19/2023] Open
Abstract
Oncomodulin (OCM, aka β-parvalbumin) is an EF-hand calcium binding protein that is expressed in a restricted set of hair cells in the peristriolar region of the mammalian utricle. In the present study, we determined the topologic distribution of OCM among hair cell phenotypes to advance our understanding of the cellular organization of the striola and the relationship of these phenotypes with characteristics of tissue polarity. The distributions of OCM-positive (OCM+) hair cells were quantified in utricles of mature C57Bl/6 mice. Immunohistochemistry was conducted using antibodies to OCM, calretinin, and β3-tubulin. Fluorophore-conjugated phalloidin was used to label hair cell stereocilia, which provided the basis for determining hair cell counts and morphologic polarizations. We found OCM expression in striolar types I and II hair cells, though the distributions were dissimilar to the native striolar type I and II distributions, favoring type I hair cells. The distribution of OCM immunoreactivity among striolar type I hair cells also reflected nonrandom distribution among type Ic and Id phenotypes (i.e., those receiving calretinin-positive and calretinin-negative calyces, respectively). However, many OCM+ hair cells were found lateral to the striola, and within the epithelial region encompassing OCM+ hair cells, the distributions of OCM+ types Ic and Id hair cells were similar to the native distributions of Ic and Id in this region. Summarily, these data provide a quantitative perspective supporting the existence of different underlying factors driving the topologic expression of OCM in hair cells than those responsible for tissue polarity characteristics associated within the utricular striola, including calretinin expression in afferent calyces.
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249
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Siletti K, Tarchini B, Hudspeth AJ. Daple coordinates organ-wide and cell-intrinsic polarity to pattern inner-ear hair bundles. Proc Natl Acad Sci U S A 2017; 114:E11170-9. [PMID: 29229865 DOI: 10.1073/pnas.1716522115] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Each hair cell of our auditory and vestibular systems transduces stimuli into electrical signals through its mechanosensitive hair bundle. Because the bundle is responsive along only a single axis, its orientation is crucial. Two systems determine hair-bundle polarity: planar cell polarity proteins, which establish axes along which hair cells are oriented, and the proteins Gαi and LGN. Investigating how these two systems are coordinated so that each hair bundle is appropriately aligned, we identified Daple. In mutants lacking Daple, hair bundles are misoriented and misshapen, a phenotype suggestive of both organ-wide and cell-intrinsic defects. Our study indicates how Daple interacts with proteins of the two systems and proposes a model for its role in determining hair-bundle polarity. The establishment of planar polarization by mammalian cells necessitates the integration of diverse signaling pathways. In the inner ear, at least two systems regulate the planar polarity of sensory hair bundles. The core planar cell polarity (PCP) proteins coordinate the orientations of hair cells across the epithelial plane. The cell-intrinsic patterning of hair bundles is implemented independently by the G protein complex classically known for orienting the mitotic spindle. Although the primary cilium also participates in each of these pathways, its role and the integration of the two systems are poorly understood. We show that Dishevelled-associating protein with a high frequency of leucine residues (Daple) interacts with PCP and cell-intrinsic signals. Regulated by the cell-intrinsic pathway, Daple is required to maintain the polarized distribution of the core PCP protein Dishevelled and to position the primary cilium at the abneural edge of the apical surface. Our results suggest that the primary cilium or an associated structure influences the domain of cell-intrinsic signals that shape the hair bundle. Daple is therefore essential to orient and pattern sensory hair bundles.
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250
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Gianoli F, Risler T, Kozlov AS. Lipid bilayer mediates ion-channel cooperativity in a model of hair-cell mechanotransduction. Proc Natl Acad Sci U S A 2017; 114:E11010-9. [PMID: 29217640 DOI: 10.1073/pnas.1713135114] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mechanoelectrical transduction in the inner ear is a biophysical process underlying the senses of hearing and balance. The key players involved in this process are mechanosensitive ion channels. They are located in the stereocilia of hair cells and opened by the tension in specialized molecular springs, the tip links, connecting adjacent stereocilia. When channels open, the tip links relax, reducing the hair-bundle stiffness. This gating compliance makes hair cells especially sensitive to small stimuli. The classical explanation for the gating compliance is that the conformational rearrangement of a single channel directly shortens the tip link. However, to reconcile theoretical models based on this mechanism with experimental data, an unrealistically large structural change of the channel is required. Experimental evidence indicates that each tip link is a dimeric molecule, associated on average with two channels at its lower end. It also indicates that the lipid bilayer modulates channel gating, although it is not clear how. Here, we design and analyze a model of mechanotransduction where each tip link attaches to two channels, mobile within the membrane. Their states and positions are coupled by membrane-mediated elastic forces arising from the interaction between the channels' hydrophobic cores and that of the lipid bilayer. This coupling induces cooperative opening and closing of the channels. The model reproduces the main properties of hair-cell mechanotransduction using only realistic parameters constrained by experimental evidence. This work provides an insight into the fundamental role that membrane-mediated ion-channel cooperativity can play in sensory physiology.
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