1
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Liu JB, Yuan HL, Zhang G, Ke JB. Comprehensive Characterization of a Subfamily of Ca 2+-Binding Proteins in Mouse and Human Retinal Neurons at Single-Cell Resolution. eNeuro 2024; 11:ENEURO.0145-24.2024. [PMID: 39260891 PMCID: PMC11419601 DOI: 10.1523/eneuro.0145-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 08/20/2024] [Accepted: 09/03/2024] [Indexed: 09/13/2024] Open
Abstract
Ca2+-binding proteins (CaBPs; CaBP1-5) are a subfamily of neuronal Ca2+ sensors with high homology to calmodulin. Notably, CaBP4, which is exclusively expressed in rod and cone photoreceptors, is crucial for maintaining normal retinal functions. However, the functional roles of CaBP1, CaBP2, and CaBP5 in the retina remain elusive, primarily due to limited understanding of their expression patterns within inner retinal neurons. In this study, we conducted a comprehensive transcript analysis using single-cell RNA sequencing datasets to investigate the gene expression profiles of CaBPs in mouse and human retinal neurons. Our findings revealed notable similarities in the overall expression patterns of CaBPs across both species. Specifically, nearly all amacrine cell, ganglion cell, and horizontal cell types exclusively expressed CaBP1. In contrast, the majority of bipolar cell types, including rod bipolar (RB) cells, expressed distinct combinations of CaBP1, CaBP2, and CaBP5, rather than a single CaBP as previously hypothesized. Remarkably, mouse rods and human cones exclusively expressed CaBP4, whereas mouse cones and human rods coexpressed both CaBP4 and CaBP5. Our single-cell reverse transcription polymerase chain reaction analysis confirmed the coexpression CaBP1 and CaBP5 in individual RBs from mice of either sex. Additionally, all three splice variants of CaBP1, primarily L-CaBP1, were detected in mouse RBs. Taken together, our study offers a comprehensive overview of the distribution of CaBPs in mouse and human retinal neurons, providing valuable insights into their roles in visual functions.
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Affiliation(s)
- Jun-Bin Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - He-Lan Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Gong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Jiang-Bin Ke
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Wenzhou 325000, China
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
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2
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Lopez JA, Romero LO, Kaung WL, Maddox JW, Vásquez V, Lee A. Caldendrin Is a Repressor of PIEZO2 Channels and Touch Sensation in Mice. J Neurosci 2024; 44:e1402232023. [PMID: 38262725 PMCID: PMC10919251 DOI: 10.1523/jneurosci.1402-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 01/25/2024] Open
Abstract
The sense of touch is crucial for cognitive, emotional, and social development and relies on mechanically activated (MA) ion channels that transduce force into an electrical signal. Despite advances in the molecular characterization of these channels, the physiological factors that control their activity are poorly understood. Here, we used behavioral assays, electrophysiological recordings, and various mouse strains (males and females analyzed separately) to investigate the role of the calmodulin-like Ca2+ sensor, caldendrin, as a key regulator of MA channels and their roles in touch sensation. In mice lacking caldendrin (Cabp1 KO), heightened responses to tactile stimuli correlate with enlarged MA currents with lower mechanical thresholds in dorsal root ganglion neurons (DRGNs). The expression pattern of caldendrin in the DRG parallels that of the major MA channel required for touch sensation, PIEZO2. In transfected cells, caldendrin interacts with and inhibits the activity of PIEZO2 in a manner that requires an alternatively spliced sequence in the N-terminal domain of caldendrin. Moreover, targeted genetic deletion of caldendrin in Piezo2-expressing DRGNs phenocopies the tactile hypersensitivity of complete Cabp1 KO mice. We conclude that caldendrin is an endogenous repressor of PIEZO2 channels and their contributions to touch sensation in DRGNs.
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Affiliation(s)
- Josue A Lopez
- Department of Neuroscience and Center for Learning and Memory, University of Texas-Austin, Austin 78712, Texas
| | - Luis O Romero
- Department of Physiology, The University of Tennessee Health Science Center, Memphis 38163, Tennessee
- Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, Memphis 38163, Tennessee
| | - Wai-Lin Kaung
- Department of Neuroscience and Center for Learning and Memory, University of Texas-Austin, Austin 78712, Texas
| | - J Wesley Maddox
- Department of Neuroscience and Center for Learning and Memory, University of Texas-Austin, Austin 78712, Texas
| | - Valeria Vásquez
- Department of Physiology, The University of Tennessee Health Science Center, Memphis 38163, Tennessee
| | - Amy Lee
- Department of Neuroscience and Center for Learning and Memory, University of Texas-Austin, Austin 78712, Texas
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3
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Boussaty EC, Tedeschi N, Novotny M, Ninoyu Y, Du E, Draf C, Zhang Y, Manor U, Scheuermann RH, Friedman R. Cochlear transcriptome analysis of an outbred mouse population (CFW). Front Cell Neurosci 2023; 17:1256619. [PMID: 38094513 PMCID: PMC10716316 DOI: 10.3389/fncel.2023.1256619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/11/2023] [Indexed: 12/20/2023] Open
Abstract
Age-related hearing loss (ARHL) is the most common cause of hearing loss and one of the most prevalent conditions affecting the elderly worldwide. Despite evidence from our lab and others about its polygenic nature, little is known about the specific genes, cell types, and pathways involved in ARHL, impeding the development of therapeutic interventions. In this manuscript, we describe, for the first time, the complete cell-type specific transcriptome of the aging mouse cochlea using snRNA-seq in an outbred mouse model in relation to auditory threshold variation. Cochlear cell types were identified using unsupervised clustering and annotated via a three-tiered approach-first by linking to expression of known marker genes, then using the NSForest algorithm to select minimum cluster-specific marker genes and reduce dimensional feature space for statistical comparison of our clusters with existing publicly-available data sets on the gEAR website, and finally, by validating and refining the annotations using Multiplexed Error Robust Fluorescence In Situ Hybridization (MERFISH) and the cluster-specific marker genes as probes. We report on 60 unique cell-types expanding the number of defined cochlear cell types by more than two times. Importantly, we show significant specific cell type increases and decreases associated with loss of hearing acuity implicating specific subsets of hair cell subtypes, ganglion cell subtypes, and cell subtypes within the stria vascularis in this model of ARHL. These results provide a view into the cellular and molecular mechanisms responsible for age-related hearing loss and pathways for therapeutic targeting.
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Affiliation(s)
- Ely Cheikh Boussaty
- Department of Otolaryngology, University of California, San Diego, La Jolla, CA, United States
| | - Neil Tedeschi
- J. Craig Venter Institute, La Jolla, CA, United States
| | - Mark Novotny
- J. Craig Venter Institute, La Jolla, CA, United States
| | - Yuzuru Ninoyu
- Department of Otolaryngology, University of California, San Diego, La Jolla, CA, United States
| | - Eric Du
- Department of Otolaryngology, University of California, San Diego, La Jolla, CA, United States
| | - Clara Draf
- Department of Otolaryngology, University of California, San Diego, La Jolla, CA, United States
| | - Yun Zhang
- J. Craig Venter Institute, La Jolla, CA, United States
| | - Uri Manor
- Department of Cell and Developmental Biology, University of California San Diego, Salk Institute for Biological Studies, Waitt Advanced Biophotonics Center, La Jolla, CA, United States
| | - Richard H. Scheuermann
- J. Craig Venter Institute, La Jolla, CA, United States
- Department of Pathology, University of California, San Diego, La Jolla, CA, United States
| | - Rick Friedman
- Department of Otolaryngology, University of California, San Diego, La Jolla, CA, United States
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4
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Boussaty EC, Tedeschi N, Novotny M, Ninoyu Y, Du E, Draf C, Zhang Y, Manor U, Scheuermann RH, Friedman R. Cochlear transcriptome analysis of an outbred mouse population (CFW). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528661. [PMID: 36824745 PMCID: PMC9948975 DOI: 10.1101/2023.02.15.528661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Age-related hearing loss (ARHL) is the most common cause of hearing loss and one of the most prevalent conditions affecting the elderly worldwide. Despite evidence from our lab and others about its polygenic nature, little is known about the specific genes, cell types and pathways involved in ARHL, impeding the development of therapeutic interventions. In this manuscript, we describe, for the first time, the complete cell-type specific transcriptome of the aging mouse cochlea using snRNA-seq in an outbred mouse model in relation to auditory threshold variation. Cochlear cell types were identified using unsupervised clustering and annotated via a three-tiered approach - first by linking to expression of known marker genes, then using the NS-Forest algorithm to select minimum cluster-specific marker genes and reduce dimensional feature space for statistical comparison of our clusters with existing publicly-available data sets on the gEAR website (https://umgear.org/), and finally, by validating and refining the annotations using Multiplexed Error Robust Fluorescence In Situ Hybridization (MERFISH) and the cluster-specific marker genes as probes. We report on 60 unique cell-types expanding the number of defined cochlear cell types by more than two times. Importantly, we show significant specific cell type increases and decreases associated with loss of hearing acuity implicating specific subsets of hair cell subtypes, ganglion cell subtypes, and cell subtypes withing the stria vascularis in this model of ARHL. These results provide a view into the cellular and molecular mechanisms responsible for age-related hearing loss and pathways for therapeutic targeting.
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Affiliation(s)
| | | | | | - Yuzuru Ninoyu
- Department of Otolaryngology, University of California, San Diego, CA
| | - Eric Du
- Department of Otolaryngology, University of California, San Diego, CA
| | - Clara Draf
- Department of Otolaryngology, University of California, San Diego, CA
| | - Yun Zhang
- J. Craig Venter Institute, La Jolla, CA
| | - Uri Manor
- Salk Institute for Biological Studies, Waitt Advanced Biophotonics Center, La Jolla, CA, United States
| | - Richard H. Scheuermann
- J. Craig Venter Institute, La Jolla, CA
- Department of Pathology, University of California, San Diego, CA
| | - Rick Friedman
- Department of Otolaryngology, University of California, San Diego, CA
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5
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Lopez JA, Yamamoto A, Vecchi JT, Hagen J, Lee K, Sonka M, Hansen MR, Lee A. Caldendrin represses neurite regeneration and growth in dorsal root ganglion neurons. Sci Rep 2023; 13:2608. [PMID: 36788334 PMCID: PMC9929226 DOI: 10.1038/s41598-023-29622-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/07/2023] [Indexed: 02/16/2023] Open
Abstract
Caldendrin is a Ca2+ binding protein that interacts with multiple effectors, such as the Cav1 L-type Ca2+ channel, which play a prominent role in regulating the outgrowth of dendrites and axons (i.e., neurites) during development and in response to injury. Here, we investigated the role of caldendrin in Cav1-dependent pathways that impinge upon neurite growth in dorsal root ganglion neurons (DRGNs). By immunofluorescence, caldendrin was localized in medium- and large- diameter DRGNs. Compared to DRGNs cultured from WT mice, DRGNs of caldendrin knockout (KO) mice exhibited enhanced neurite regeneration and outgrowth. Strong depolarization, which normally represses neurite growth through activation of Cav1 channels, had no effect on neurite growth in DRGN cultures from female caldendrin KO mice. Remarkably, DRGNs from caldendrin KO males were no different from those of WT males in terms of depolarization-dependent neurite growth repression. We conclude that caldendrin opposes neurite regeneration and growth, and this involves coupling of Cav1 channels to growth-inhibitory pathways in DRGNs of females but not males.
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Affiliation(s)
- Josue A Lopez
- Department of Neuroscience, University of Texas-Austin, 100 E. 24th St., Austin, TX, 78712, USA
| | - Annamarie Yamamoto
- Department of Neuroscience, University of Texas-Austin, 100 E. 24th St., Austin, TX, 78712, USA
| | - Joseph T Vecchi
- Department of Molecular Physiology and Biophysics and Otolaryngology Head-Neck Surgery, Iowa Neuroscience Institute, Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, 52242, USA
| | - Jussara Hagen
- Department of Molecular Physiology and Biophysics and Otolaryngology Head-Neck Surgery, Iowa Neuroscience Institute, Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, 52242, USA
| | - Kyungmoo Lee
- Electrical and Computer Engineering, Iowa Institute for Biomedical Imaging, University of Iowa, 51 Newton Rd. Iowa City, Iowa, 52242, USA
| | - Milan Sonka
- Electrical and Computer Engineering, Iowa Institute for Biomedical Imaging, University of Iowa, 51 Newton Rd. Iowa City, Iowa, 52242, USA
| | - Marlan R Hansen
- Department of Molecular Physiology and Biophysics and Otolaryngology Head-Neck Surgery, Iowa Neuroscience Institute, Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, 52242, USA
| | - Amy Lee
- Department of Neuroscience, University of Texas-Austin, 100 E. 24th St., Austin, TX, 78712, USA.
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6
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Liu W, Chen H, Zhu X, Yu H. Expression of Calbindin-D28K in the Developing and Adult Mouse Cochlea. J Histochem Cytochem 2022; 70:583-596. [PMID: 35975307 PMCID: PMC9393511 DOI: 10.1369/00221554221119543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Herein, we aimed to use double-labeling immunofluorescence to describe the expression pattern of Calbindin-D28K (CaBP28K) in the mouse cochlea from late embryonic (E) stages to the adulthood. CaBP28K was expressed in the inner hair cells (IHCs) and the greater epithelial ridge (GER) at E17. In addition, its expression was observed in the interdental cells. On postnatal day 1 (P1), CaBP28K immunoreactivity was observed in the IHCs and outer hair cells (OHCs) and was also specifically expressed in the nucleus and the cytoplasm of spiral ganglion neurons (SGNs). At P8, CaBP28K labeling disappeared from the interdental cells, and the CaBP28K-positive domain within the GER shifted from the entire cytoplasm to only the apical and basal regions. At P14, CaBP28K immunoreactivity was lost from the GER; however, its expression in the IHCs and OHCs, as well as the SGNs, persisted into adulthood. The identification of CaBP28K in the hair cells (HCs) and cuticular plates, as well as SGNs, was confirmed by its colocalization with several markers for Sox2, Myosin VIIa, Phalloidin, and Tuj1. We also detected colocalization with calmodulin in the cytoplasm of both HCs and SGNs. Western blot revealed an increase in CaBP28K postnatal expression in the mouse cochlea.
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Affiliation(s)
- Wenjing Liu
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongda Hospital, Southeast University, Nanjing, China
| | - Huijun Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongda Hospital, Southeast University, Nanjing, China
| | - Xin Zhu
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongda Hospital, Southeast University, Nanjing, China
| | - Hao Yu
- Anhui Province Key Laboratory of Biological Macro-Molecules Research, Wannan Medical College, Wuhu, China
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7
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Oncomodulin (OCM) uniquely regulates calcium signaling in neonatal cochlear outer hair cells. Cell Calcium 2022; 105:102613. [PMID: 35797824 PMCID: PMC9297295 DOI: 10.1016/j.ceca.2022.102613] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 11/23/2022]
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8
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Oestreicher D, Picher MM, Rankovic V, Moser T, Pangrsic T. Cabp2-Gene Therapy Restores Inner Hair Cell Calcium Currents and Improves Hearing in a DFNB93 Mouse Model. Front Mol Neurosci 2021; 14:689415. [PMID: 34489639 PMCID: PMC8417311 DOI: 10.3389/fnmol.2021.689415] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/28/2021] [Indexed: 12/02/2022] Open
Abstract
Clinical management of auditory synaptopathies like other genetic hearing disorders is currently limited to the use of hearing aids or cochlear implants. However, future gene therapy promises restoration of hearing in selected forms of monogenic hearing impairment, in which cochlear morphology is preserved over a time window that enables intervention. This includes non-syndromic autosomal recessive hearing impairment DFNB93, caused by defects in the CABP2 gene. Calcium-binding protein 2 (CaBP2) is a potent modulator of inner hair cell (IHC) voltage-gated calcium channels CaV1.3. Based on disease modeling in Cabp2–/– mice, DFNB93 hearing impairment has been ascribed to enhanced steady-state inactivation of IHC CaV1.3 channels, effectively limiting their availability to trigger synaptic transmission. This, however, does not seem to interfere with cochlear development and does not cause early degeneration of hair cells or their synapses. Here, we studied the potential of a gene therapeutic approach for the treatment of DFNB93. We used AAV2/1 and AAV-PHP.eB viral vectors to deliver the Cabp2 coding sequence into IHCs of early postnatal Cabp2–/– mice and assessed the level of restoration of hair cell function and hearing. Combining in vitro and in vivo approaches, we observed high transduction efficiency, and restoration of IHC CaV1.3 function resulting in improved hearing of Cabp2–/– mice. These preclinical results prove the feasibility of DFNB93 gene therapy.
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Affiliation(s)
- David Oestreicher
- Experimental Otology Group, InnerEarLab, Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Maria Magdalena Picher
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Vladan Rankovic
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Restorative Cochlear Genomics Group, Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
| | - Tobias Moser
- Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, Göttingen, Germany
| | - Tina Pangrsic
- Experimental Otology Group, InnerEarLab, Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, Göttingen, Germany
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9
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Lan Y, Tao Y, Wang Y, Ke J, Yang Q, Liu X, Su B, Wu Y, Lin CP, Zhong G. Recent development of AAV-based gene therapies for inner ear disorders. Gene Ther 2020; 27:329-337. [PMID: 32424232 PMCID: PMC7445886 DOI: 10.1038/s41434-020-0155-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/12/2020] [Accepted: 04/27/2020] [Indexed: 01/07/2023]
Abstract
Gene therapy for auditory diseases is gradually maturing. Recent progress in gene therapy treatments for genetic and acquired hearing loss has demonstrated the feasibility in animal models. However, a number of hurdles, such as lack of safe viral vector with high efficiency and specificity, robust deafness large animal models, translating animal studies to clinic etc., still remain to be solved. It is necessary to overcome these challenges in order to effectively recover auditory function in human patients. Here, we review the progress made in our group, especially our efforts to make more effective and cell type-specific viral vectors for targeting cochlea cells.
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Affiliation(s)
- Yiyang Lan
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yong Tao
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200011, China
| | - Yunfeng Wang
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Junzi Ke
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Qiuxiang Yang
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Xiaoyi Liu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Bing Su
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yiling Wu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Chao-Po Lin
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Guisheng Zhong
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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10
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Dolphin AC, Lee A. Presynaptic calcium channels: specialized control of synaptic neurotransmitter release. Nat Rev Neurosci 2020; 21:213-229. [PMID: 32161339 PMCID: PMC7873717 DOI: 10.1038/s41583-020-0278-2] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2020] [Indexed: 11/09/2022]
Abstract
Chemical synapses are heterogeneous junctions formed between neurons that are specialized for the conversion of electrical impulses into the exocytotic release of neurotransmitters. Voltage-gated Ca2+ channels play a pivotal role in this process as they are the major conduits for the Ca2+ ions that trigger the fusion of neurotransmitter-containing vesicles with the presynaptic membrane. Alterations in the intrinsic function of these channels and their positioning within the active zone can profoundly alter the timing and strength of synaptic output. Advances in optical and electron microscopic imaging, structural biology and molecular techniques have facilitated recent breakthroughs in our understanding of the properties of voltage-gated Ca2+ channels that support their presynaptic functions. Here we examine the nature of these channels, how they are trafficked to and anchored within presynaptic boutons, and the mechanisms that allow them to function optimally in shaping the flow of information through neural circuits.
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Affiliation(s)
- Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK.
| | - Amy Lee
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA.
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11
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Lee S, Dondzillo A, Gubbels SP, Raphael Y. Practical aspects of inner ear gene delivery for research and clinical applications. Hear Res 2020; 394:107934. [PMID: 32204962 DOI: 10.1016/j.heares.2020.107934] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/26/2020] [Accepted: 02/28/2020] [Indexed: 12/24/2022]
Abstract
The application of gene therapy is widely expanding in research and continuously improving in preparation for clinical applications. The inner ear is an attractive target for gene therapy for treating environmental and genetic diseases in both the auditory and vestibular systems. With the lack of spontaneous cochlear hair cell replacement, hair cell regeneration in adult mammals is among the most important goals of gene therapy. In addition, correcting gene defects can open up a new era for treating inner ear diseases. The relative isolation and small size of the inner ear dictate local administration routes and carefully calculated small volumes of reagents. In the current review, we will cover effective timing, injection routes and types of vectors for successful gene delivery to specific target cells within the inner ear. Differences between research purposes and clinical applications are also discussed.
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Affiliation(s)
- Sungsu Lee
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, Michigan Medicine, Ann Arbor, MI, USA
| | - Anna Dondzillo
- Department of Otolaryngology, Head and Neck Surgery, University of Colorado School of Medicine, Aurora, CO, USA
| | - Samuel P Gubbels
- Department of Otolaryngology, Head and Neck Surgery, University of Colorado School of Medicine, Aurora, CO, USA
| | - Yehoash Raphael
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, Michigan Medicine, Ann Arbor, MI, USA.
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12
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Ortner NJ, Pinggera A, Hofer NT, Siller A, Brandt N, Raffeiner A, Vilusic K, Lang I, Blum K, Obermair GJ, Stefan E, Engel J, Striessnig J. RBP2 stabilizes slow Cav1.3 Ca 2+ channel inactivation properties of cochlear inner hair cells. Pflugers Arch 2019; 472:3-25. [PMID: 31848688 PMCID: PMC6960213 DOI: 10.1007/s00424-019-02338-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/18/2019] [Accepted: 12/04/2019] [Indexed: 01/31/2023]
Abstract
Cav1.3 L-type Ca2+ channels (LTCCs) in cochlear inner hair cells (IHCs) are essential for hearing as they convert sound-induced graded receptor potentials into tonic postsynaptic glutamate release. To enable fast and indefatigable presynaptic Ca2+ signaling, IHC Cav1.3 channels exhibit a negative activation voltage range and uniquely slow inactivation kinetics. Interaction with CaM-like Ca2+-binding proteins inhibits Ca2+-dependent inactivation, while the mechanisms underlying slow voltage-dependent inactivation (VDI) are not completely understood. Here we studied if the complex formation of Cav1.3 LTCCs with the presynaptic active zone proteins RIM2α and RIM-binding protein 2 (RBP2) can stabilize slow VDI. We detected both RIM2α and RBP isoforms in adult mouse IHCs, where they co-localized with Cav1.3 and synaptic ribbons. Using whole-cell patch-clamp recordings (tsA-201 cells), we assessed their effect on the VDI of the C-terminal full-length Cav1.3 (Cav1.3L) and a short splice variant (Cav1.342A) that lacks the C-terminal RBP2 interaction site. When co-expressed with the auxiliary β3 subunit, RIM2α alone (Cav1.342A) or RIM2α/RBP2 (Cav1.3L) reduced Cav1.3 VDI to a similar extent as observed in IHCs. Membrane-anchored β2 variants (β2a, β2e) that inhibit inactivation on their own allowed no further modulation of inactivation kinetics by RIM2α/RBP2. Moreover, association with RIM2α and/or RBP2 consolidated the negative Cav1.3 voltage operating range by shifting the channel's activation threshold toward more hyperpolarized potentials. Taken together, the association with "slow" β subunits (β2a, β2e) or presynaptic scaffolding proteins such as RIM2α and RBP2 stabilizes physiological gating properties of IHC Cav1.3 LTCCs in a splice variant-dependent manner ensuring proper IHC function.
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Affiliation(s)
- Nadine J Ortner
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
| | - Alexandra Pinggera
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Nadja T Hofer
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Anita Siller
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Niels Brandt
- Department of Biophysics and CIPMM, Saarland University, Homburg, Germany
| | - Andrea Raffeiner
- Institute of Biochemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Kristina Vilusic
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Isabelle Lang
- Department of Biophysics and CIPMM, Saarland University, Homburg, Germany
| | - Kerstin Blum
- Department of Biophysics and CIPMM, Saarland University, Homburg, Germany
| | - Gerald J Obermair
- Division of Physiology, Medical University Innsbruck, Innsbruck, Austria.,Division Physiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Eduard Stefan
- Institute of Biochemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Jutta Engel
- Department of Biophysics and CIPMM, Saarland University, Homburg, Germany
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
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13
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Burgoyne RD, Helassa N, McCue HV, Haynes LP. Calcium Sensors in Neuronal Function and Dysfunction. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a035154. [PMID: 30833454 DOI: 10.1101/cshperspect.a035154] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Calcium signaling in neurons as in other cell types can lead to varied changes in cellular function. Neuronal Ca2+ signaling processes have also become adapted to modulate the function of specific pathways over a wide variety of time domains and these can have effects on, for example, axon outgrowth, neuronal survival, and changes in synaptic strength. Ca2+ also plays a key role in synapses as the trigger for fast neurotransmitter release. Given its physiological importance, abnormalities in neuronal Ca2+ signaling potentially underlie many different neurological and neurodegenerative diseases. The mechanisms by which changes in intracellular Ca2+ concentration in neurons can bring about diverse responses is underpinned by the roles of ubiquitous or specialized neuronal Ca2+ sensors. It has been established that synaptotagmins have key functions in neurotransmitter release, and, in addition to calmodulin, other families of EF-hand-containing neuronal Ca2+ sensors, including the neuronal calcium sensor (NCS) and the calcium-binding protein (CaBP) families, play important physiological roles in neuronal Ca2+ signaling. It has become increasingly apparent that these various Ca2+ sensors may also be crucial for aspects of neuronal dysfunction and disease either indirectly or directly as a direct consequence of genetic variation or mutations. An understanding of the molecular basis for the regulation of the targets of the Ca2+ sensors and the physiological roles of each protein in identified neurons may contribute to future approaches to the development of treatments for a variety of human neuronal disorders.
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Affiliation(s)
- Robert D Burgoyne
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Nordine Helassa
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Hannah V McCue
- Centre for Genomic Research, University of Liverpool, Liverpool, United Kingdom
| | - Lee P Haynes
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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14
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Pangrsic T, Singer JH, Koschak A. Voltage-Gated Calcium Channels: Key Players in Sensory Coding in the Retina and the Inner Ear. Physiol Rev 2019; 98:2063-2096. [PMID: 30067155 DOI: 10.1152/physrev.00030.2017] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Calcium influx through voltage-gated Ca (CaV) channels is the first step in synaptic transmission. This review concerns CaV channels at ribbon synapses in primary sense organs and their specialization for efficient coding of stimuli in the physical environment. Specifically, we describe molecular, biochemical, and biophysical properties of the CaV channels in sensory receptor cells of the retina, cochlea, and vestibular apparatus, and we consider how such properties might change over the course of development and contribute to synaptic plasticity. We pay particular attention to factors affecting the spatial arrangement of CaV channels at presynaptic, ribbon-type active zones, because the spatial relationship between CaV channels and release sites has been shown to affect synapse function critically in a number of systems. Finally, we review identified synaptopathies affecting sensory systems and arising from dysfunction of L-type, CaV1.3, and CaV1.4 channels or their protein modulatory elements.
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Affiliation(s)
- Tina Pangrsic
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Joshua H Singer
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Alexandra Koschak
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
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15
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Vélez-Ortega AC, Frolenkov GI. Building and repairing the stereocilia cytoskeleton in mammalian auditory hair cells. Hear Res 2019; 376:47-57. [PMID: 30638948 DOI: 10.1016/j.heares.2018.12.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/19/2018] [Accepted: 12/28/2018] [Indexed: 10/27/2022]
Abstract
Despite all recent achievements in identification of the molecules that are essential for the structure and mechanosensory function of stereocilia bundles in the auditory hair cells of mammalian species, we still have only a rudimentary understanding of the mechanisms of stereocilia formation, maintenance, and repair. Important molecular differences distinguishing mammalian auditory hair cells from hair cells of other types and species have been recently revealed. In addition, we are beginning to solve the puzzle of the apparent life-long stability of the stereocilia bundles in these cells. New data link the stability of the cytoskeleton in the mammalian auditory stereocilia with the normal activity of mechanotransduction channels. These data suggest new ideas on how a terminally-differentiated non-regenerating hair cell in the mammalian cochlea may repair and tune its stereocilia bundle throughout the life span of the organism.
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Affiliation(s)
- A Catalina Vélez-Ortega
- Department of Physiology, University of Kentucky, 800 Rose St., Lexington, KY, 40536-0298, USA.
| | - Gregory I Frolenkov
- Department of Physiology, University of Kentucky, 800 Rose St., Lexington, KY, 40536-0298, USA.
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16
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Trans-differentiation of outer hair cells into inner hair cells in the absence of INSM1. Nature 2018; 563:691-695. [PMID: 30305733 PMCID: PMC6279423 DOI: 10.1038/s41586-018-0570-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/14/2018] [Indexed: 01/09/2023]
Abstract
The mammalian cochlea contains two types of mechanosensory hair cells (HCs) that play different and critical roles in hearing. Inner hair cells (IHCs), with an elaborate presynaptic apparatus, signal to cochlear neurons and communicate sound information to the brain. Outer hair cells (OHCs) mechanically amplify sound-induced vibrations, enabling enhanced sensitivity to sound and sharp tuning. Cochlear HCs are solely generated during development and their death, most often of OHCs, is the main cause of deafness. OHCs and IHCs, together with supporting cells, originate embryonically from the prosensory region of the otocyst, but how HCs differentiate into two different types is unknown1–3. Here we show that Insm1, which encodes a zinc finger protein transiently expressed in nascent OHCs, consolidates their fate by preventing trans-differentiation into IHCs. In the absence of INSM1 many HCs born embryonically as OHCs switch fates to become mature IHCs. In order to identify the genetic mechanisms by which Insm1 operates, we compared transcriptomes of immature IHCs vs OHCs, as well as OHCs with and without INSM1. OHCs lacking INSM1 upregulate a set of genes, most of which are normally preferentially expressed by IHCs. The homeotic cell transformation of OHCs without INSM1 into IHCs reveals for the first time a mechanism by which these neighboring mechanosensory cells begin to differ: INSM1 represses a core set of early IHC-enriched genes in embryonic OHCs and makes them unresponsive to an IHC-inducing gradient, so that they proceed to mature as OHCs. Without INSM1, some of the OHCs upregulating these few IHC-enriched transcripts trans-differentiate into IHCs, revealing the first candidate genes for IHC-specific differentiation.
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17
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Yang T, Britt JK, Cintrón-Pérez CJ, Vázquez-Rosa E, Tobin KV, Stalker G, Hardie J, Taugher RJ, Wemmie J, Pieper AA, Lee A. Ca 2+-Binding Protein 1 Regulates Hippocampal-dependent Memory and Synaptic Plasticity. Neuroscience 2018; 380:90-102. [PMID: 29660444 DOI: 10.1016/j.neuroscience.2018.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/16/2018] [Accepted: 04/05/2018] [Indexed: 11/25/2022]
Abstract
Ca2+-binding protein 1 (CaBP1) is a Ca2+-sensing protein similar to calmodulin that potently regulates voltage-gated Ca2+ channels. Unlike calmodulin, however, CaBP1 is mainly expressed in neuronal cell-types and enriched in the hippocampus, where its function is unknown. Here, we investigated the role of CaBP1 in hippocampal-dependent behaviors using mice lacking expression of CaBP1 (C-KO). By western blot, the largest CaBP1 splice variant, caldendrin, was detected in hippocampal lysates from wild-type (WT) but not C-KO mice. Compared to WT mice, C-KO mice exhibited mild deficits in spatial learning and memory in both the Barnes maze and in Morris water maze reversal learning. In contextual but not cued fear-conditioning assays, C-KO mice showed greater freezing responses than WT mice. In addition, the number of adult-born neurons in the hippocampus of C-KO mice was ∼40% of that in WT mice, as measured by bromodeoxyuridine labeling. Moreover, hippocampal long-term potentiation was significantly reduced in C-KO mice. We conclude that CaBP1 is required for cellular mechanisms underlying optimal encoding of hippocampal-dependent spatial and fear-related memories.
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Affiliation(s)
- Tian Yang
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - Jeremiah K Britt
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Psychiatry, University of Iowa, Iowa City, IA 52242, USA
| | - Coral J Cintrón-Pérez
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Psychiatry, University of Iowa, Iowa City, IA 52242, USA
| | - Edwin Vázquez-Rosa
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Psychiatry, University of Iowa, Iowa City, IA 52242, USA
| | - Kevin V Tobin
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - Grant Stalker
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - Jason Hardie
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - Rebecca J Taugher
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Psychiatry, University of Iowa, Iowa City, IA 52242, USA
| | - John Wemmie
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Psychiatry, University of Iowa, Iowa City, IA 52242, USA
| | - Andrew A Pieper
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Neurology, University of Iowa, Iowa City, IA 52242, USA; Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Psychiatry, University of Iowa, Iowa City, IA 52242, USA; Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Free Radical, University of Iowa, Iowa City, IA 52242, USA; Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Radiation Biology Program, University of Iowa, Iowa City, IA 52242, USA; Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Radiation Oncology Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242, USA; Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Veterans Affairs, University of Iowa, Iowa City, IA 52242, USA; Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Pappajohn Biomedical Institute and Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Amy Lee
- Departments of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, Neurology, University of Iowa, Iowa City, IA 52242, USA.
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18
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Yang T, Hu N, Pangršič T, Green S, Hansen M, Lee A. Functions of CaBP1 and CaBP2 in the peripheral auditory system. Hear Res 2018; 364:48-58. [PMID: 29661613 DOI: 10.1016/j.heares.2018.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/13/2018] [Accepted: 04/02/2018] [Indexed: 12/29/2022]
Abstract
CaBPs are a family of Ca2+ binding proteins related to calmodulin. Two CaBP family members, CaBP1 and CaBP2, are highly expressed in the cochlea. Here, we investigated the significance of CaBP1 and CaBP2 for hearing in mice lacking expression of these proteins (CaBP1 KO and CaBP2 KO) using auditory brain responses (ABRs) and distortion product otoacoustic emissions (DPOAEs). In CaBP1 KO mice, ABR wave I was larger in amplitude, and shorter in latency and faster in decay, suggestive of enhanced synchrony of auditory nerve fibers. This interpretation was supported by the greater excitability of CaBP1 KO than WT neurons in whole-cell patch clamp recordings of spiral ganglion neurons in culture, and normal presynaptic function of CaBP1 KO IHCs. DPOAEs and ABR thresholds were normal in 4-week old CaBP1 KO mice, but elevated ABR thresholds became evident at 32 kHz at 9 weeks, and at 8 and 16 kHz by 6 months of age. In contrast, CaBP2 KO mice exhibited significant ABR threshold elevations at 4 weeks of age that became more severe in the mid-frequency range by 9 weeks. Though normal at 4 weeks, DPOAEs in CaBP2 KO mice were significantly reduced in the mid-frequency range by 9 weeks. Our results reveal requirements for CaBP1 and CaBP2 in the peripheral auditory system and highlight the diverse modes by which CaBPs influence sensory processing.
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Affiliation(s)
- Tian Yang
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA
| | - Ning Hu
- Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Tina Pangršič
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Steven Green
- Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Marlan Hansen
- Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA
| | - Amy Lee
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Neurology, University of Iowa, Iowa City, IA 52242, USA.
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19
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Yang T, Choi JE, Soh D, Tobin K, Joiner ML, Hansen M, Lee A. CaBP1 regulates Ca v1 L-type Ca 2+ channels and their coupling to neurite growth and gene transcription in mouse spiral ganglion neurons. Mol Cell Neurosci 2018; 88:342-352. [PMID: 29548764 DOI: 10.1016/j.mcn.2018.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/07/2018] [Accepted: 03/12/2018] [Indexed: 12/19/2022] Open
Abstract
CaBP1 is a Ca2+ binding protein that is widely expressed in neurons in the brain, retina, and cochlea. In heterologous expression systems, CaBP1 interacts with and regulates voltage-gated Cav Ca2+ channels but whether this is the case in neurons is unknown. Here, we investigated the cellular functions of CaBP1 in cochlear spiral ganglion neurons (SGNs), which express high levels of CaBP1. Consistent with the role of CaBP1 as a suppressor of Ca2+-dependent inactivation (CDI) of Cav1 (L-type) channels, Cav1 currents underwent greater CDI in SGNs from mice lacking CaBP1 (C-KO) than in wild-type (WT) SGNs. The coupling of Cav1 channels to downstream signaling pathways was also disrupted in C-KO SGNs. Activity-dependent repression of neurite growth was significantly blunted and unresponsive to Cav1 antagonists in C-KO SGNs in contrast to WT SGNs. Moreover, Cav1-mediated Ca2+ signals and phosphorylation of cAMP-response element binding protein were reduced in C-KO SGNs compared to WT SGNs. Our findings establish a role for CaBP1 as an essential regulator of Cav1 channels in SGNs and their coupling to downstream pathways controlling activity-dependent transcription and neurite growth.
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Affiliation(s)
- Tian Yang
- Departments of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA
| | - Ji-Eun Choi
- Departments of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA
| | - Daniel Soh
- Departments of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA
| | - Kevin Tobin
- Departments of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA
| | - Mei-Ling Joiner
- Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA
| | - Marlan Hansen
- Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Neurosurgery, University of Iowa, Iowa City, IA 52242, USA
| | - Amy Lee
- Departments of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Neurology, University of Iowa, Iowa City, IA 52242, USA.
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20
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Ca 2+-binding protein 2 inhibits Ca 2+-channel inactivation in mouse inner hair cells. Proc Natl Acad Sci U S A 2017; 114:E1717-E1726. [PMID: 28183797 DOI: 10.1073/pnas.1617533114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Ca2+-binding protein 2 (CaBP2) inhibits the inactivation of heterologously expressed voltage-gated Ca2+ channels of type 1.3 (CaV1.3) and is defective in human autosomal-recessive deafness 93 (DFNB93). Here, we report a newly identified mutation in CABP2 that causes a moderate hearing impairment likely via nonsense-mediated decay of CABP2-mRNA. To study the mechanism of hearing impairment resulting from CABP2 loss of function, we disrupted Cabp2 in mice (Cabp2LacZ/LacZ ). CaBP2 was expressed by cochlear hair cells, preferentially in inner hair cells (IHCs), and was lacking from the postsynaptic spiral ganglion neurons (SGNs). Cabp2LacZ/LacZ mice displayed intact cochlear amplification but impaired auditory brainstem responses. Patch-clamp recordings from Cabp2LacZ/LacZ IHCs revealed enhanced Ca2+-channel inactivation. The voltage dependence of activation and the number of Ca2+ channels appeared normal in Cabp2LacZ/LacZ mice, as were ribbon synapse counts. Recordings from single SGNs showed reduced spontaneous and sound-evoked firing rates. We propose that CaBP2 inhibits CaV1.3 Ca2+-channel inactivation, and thus sustains the availability of CaV1.3 Ca2+ channels for synaptic sound encoding. Therefore, we conclude that human deafness DFNB93 is an auditory synaptopathy.
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