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Lisek M, Tomczak J, Boczek T, Zylinska L. Calcium-Associated Proteins in Neuroregeneration. Biomolecules 2024; 14:183. [PMID: 38397420 PMCID: PMC10887043 DOI: 10.3390/biom14020183] [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: 12/30/2023] [Revised: 01/27/2024] [Accepted: 02/01/2024] [Indexed: 02/25/2024] Open
Abstract
The dysregulation of intracellular calcium levels is a critical factor in neurodegeneration, leading to the aberrant activation of calcium-dependent processes and, ultimately, cell death. Ca2+ signals vary in magnitude, duration, and the type of neuron affected. A moderate Ca2+ concentration can initiate certain cellular repair pathways and promote neuroregeneration. While the peripheral nervous system exhibits an intrinsic regenerative capability, the central nervous system has limited self-repair potential. There is evidence that significant variations exist in evoked calcium responses and axonal regeneration among neurons, and individual differences in regenerative capacity are apparent even within the same type of neurons. Furthermore, some studies have shown that neuronal activity could serve as a potent regulator of this process. The spatio-temporal patterns of calcium dynamics are intricately controlled by a variety of proteins, including channels, ion pumps, enzymes, and various calcium-binding proteins, each of which can exert either positive or negative effects on neural repair, depending on the cellular context. In this concise review, we focus on several calcium-associated proteins such as CaM kinase II, GAP-43, oncomodulin, caldendrin, calneuron, and NCS-1 in order to elaborate on their roles in the intrinsic mechanisms governing neuronal regeneration following traumatic damage processes.
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Affiliation(s)
| | | | | | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University of Lodz, 92-215 Lodz, Poland; (M.L.); (J.T.); (T.B.)
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2
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Lugano DI, Barrett LN, Chaput D, Park MA, Westerheide SD. CCAR-1 works together with the U2AF large subunit UAF-1 to regulate alternative splicing. RNA Biol 2024; 21:1-11. [PMID: 38126797 PMCID: PMC10761121 DOI: 10.1080/15476286.2023.2289707] [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] [Accepted: 11/17/2023] [Indexed: 12/23/2023] Open
Abstract
The Cell Division Cycle and Apoptosis Regulator (CCAR) protein family members have recently emerged as regulators of alternative splicing and transcription, as well as having other key physiological functions. For example, mammalian CCAR2/DBC1 forms a complex with the zinc factor protein ZNF326 to integrate alternative splicing with RNA polymerase II transcriptional elongation in AT-rich regions of the DNA. Additionally, Caenorhabditis elegans CCAR-1, a homolog to mammalian CCAR2, facilitates the alternative splicing of the perlecan unc-52 gene. However, much about the CCAR family's role in alternative splicing is unknown. Here, we have examined the role of CCAR-1 in genome-wide alternative splicing in Caenorhabditis elegans and have identified new alternative splicing targets of CCAR-1 using RNA sequencing. Also, we found that CCAR-1 interacts with the spliceosome factors UAF-1 and UAF-2 using mass spectrometry, and that knockdown of ccar-1 affects alternative splicing patterns, motility, and proteostasis of UAF-1 mutant worms. Collectively, we demonstrate the role of CCAR-1 in regulating global alternative splicing in C. elegans and in conjunction with UAF-1.
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Affiliation(s)
- Doreen I. Lugano
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Lindsey N. Barrett
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Dale Chaput
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Margaret A. Park
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Sandy D. Westerheide
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
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Yang Y, Murtha K, Climer LK, Ceriani F, Thompson P, Hornak AJ, Marcotti W, Simmons DD. Oncomodulin regulates spontaneous calcium signalling and maturation of afferent innervation in cochlear outer hair cells. J Physiol 2023; 601:4291-4308. [PMID: 37642186 PMCID: PMC10621907 DOI: 10.1113/jp284690] [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: 03/14/2023] [Accepted: 08/08/2023] [Indexed: 08/31/2023] Open
Abstract
Cochlear outer hair cells (OHCs) are responsible for the exquisite frequency selectivity and sensitivity of mammalian hearing. During development, the maturation of OHC afferent connectivity is refined by coordinated spontaneous Ca2+ activity in both sensory and non-sensory cells. Calcium signalling in neonatal OHCs can be modulated by oncomodulin (OCM, β-parvalbumin), an EF-hand calcium-binding protein. Here, we investigated whether OCM regulates OHC spontaneous Ca2+ activity and afferent connectivity during development. Using a genetically encoded Ca2+ sensor (GCaMP6s) expressed in OHCs in wild-type (Ocm+/+ ) and Ocm knockout (Ocm-/- ) littermates, we found increased spontaneous Ca2+ activity and upregulation of purinergic receptors in OHCs from Ocm-/- cochlea immediately following birth. The afferent synaptic maturation of OHCs was delayed in the absence of OCM, leading to an increased number of ribbon synapses and afferent fibres on Ocm-/- OHCs before hearing onset. We propose that OCM regulates the spontaneous Ca2+ signalling in the developing cochlea and the maturation of OHC afferent innervation. KEY POINTS: Cochlear outer hair cells (OHCs) exhibit spontaneous Ca2+ activity during a narrow period of neonatal development. OHC afferent maturation and connectivity requires spontaneous Ca2+ activity. Oncomodulin (OCM, β-parvalbumin), an EF-hand calcium-binding protein, modulates Ca2+ signals in immature OHCs. Using transgenic mice that endogenously expressed a Ca2+ sensor, GCaMP6s, we found increased spontaneous Ca2+ activity and upregulated purinergic receptors in Ocm-/- OHCs. The maturation of afferent synapses in Ocm-/- OHCs was also delayed, leading to an upregulation of ribbon synapses and afferent fibres in Ocm-/- OHCs before hearing onset. We propose that OCM plays an important role in modulating Ca2+ activity, expression of Ca2+ channels and afferent innervation in developing OHCs.
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Affiliation(s)
- Yang Yang
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Kaitlin Murtha
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Leslie K. Climer
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Federico Ceriani
- School of Biosciences, University of Sheffield, S10 2TN Sheffield, United Kingdom
| | - Pierce Thompson
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Aubrey J. Hornak
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Walter Marcotti
- School of Biosciences, University of Sheffield, S10 2TN Sheffield, United Kingdom
- Sheffield Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Dwayne D. Simmons
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
- School of Biosciences, University of Sheffield, S10 2TN Sheffield, United Kingdom
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA
- Department of Psychology and Neuroscience, Baylor University, Waco, TX
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4
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Leclère JC, Dulon D. Otoferlin as a multirole Ca 2+ signaling protein: from inner ear synapses to cancer pathways. Front Cell Neurosci 2023; 17:1197611. [PMID: 37538852 PMCID: PMC10394277 DOI: 10.3389/fncel.2023.1197611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 06/28/2023] [Indexed: 08/05/2023] Open
Abstract
Humans have six members of the ferlin protein family: dysferlin, myoferlin, otoferlin, fer1L4, fer1L5, and fer1L6. These proteins share common features such as multiple Ca2+-binding C2 domains, FerA domains, and membrane anchoring through their single C-terminal transmembrane domain, and are believed to play a key role in calcium-triggered membrane fusion and vesicle trafficking. Otoferlin plays a crucial role in hearing and vestibular function. In this review, we will discuss how we see otoferlin working as a Ca2+-dependent mechanical sensor regulating synaptic vesicle fusion at the hair cell ribbon synapses. Although otoferlin is also present in the central nervous system, particularly in the cortex and amygdala, its role in brain tissues remains unknown. Mutations in the OTOF gene cause one of the most frequent genetic forms of congenital deafness, DFNB9. These mutations produce severe to profound hearing loss due to a defect in synaptic excitatory glutamatergic transmission between the inner hair cells and the nerve fibers of the auditory nerve. Gene therapy protocols that allow normal rescue expression of otoferlin in hair cells have just started and are currently in pre-clinical phase. In parallel, studies have linked ferlins to cancer through their effect on cell signaling and development, allowing tumors to form and cancer cells to adapt to a hostile environment. Modulation by mechanical forces and Ca2+ signaling are key determinants of the metastatic process. Although ferlins importance in cancer has not been extensively studied, data show that otoferlin expression is significantly associated with survival in specific cancer types, including clear cell and papillary cell renal carcinoma, and urothelial bladder cancer. These findings indicate a role for otoferlin in the carcinogenesis of these tumors, which requires further investigation to confirm and understand its exact role, particularly as it varies by tumor site. Targeting this protein may lead to new cancer therapies.
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Affiliation(s)
- Jean-Christophe Leclère
- Department of Head and Neck Surgery, Brest University Hospital, Brest, France
- Laboratory of Neurophysiologie de la Synapse Auditive, Université de Bordeaux, Bordeaux, France
| | - Didier Dulon
- Laboratory of Neurophysiologie de la Synapse Auditive, Université de Bordeaux, Bordeaux, France
- Institut de l’Audition, Institut Pasteur & INSERM UA06, Paris, France
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5
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Yang Y, Murtha K, Climer LK, Ceriani F, Thompson P, Hornak AJ, Marcotti W, Simmons DD. Oncomodulin Regulates Spontaneous Calcium Signaling and Maturation of Afferent Innervation in Cochlear Outer Hair Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.01.529895. [PMID: 36909575 PMCID: PMC10002690 DOI: 10.1101/2023.03.01.529895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Cochlear outer hair cells (OHCs) are responsible for the exquisite frequency selectivity and sensitivity of mammalian hearing. During development, the maturation of OHC afferent connectivity is refined by coordinated spontaneous Ca 2+ activity in both sensory and non-sensory cells. Calcium signaling in neonatal OHCs can be modulated by Oncomodulin (OCM, β-parvalbumin), an EF-hand calcium-binding protein. Here, we investigated whether OCM regulates OHC spontaneous Ca 2+ activity and afferent connectivity during development. Using a genetically encoded Ca 2+ sensor (GCaMP6s) expressed in OHCs in wild-type (Ocm +/+ ) and Ocm knockout (Ocm -/- ) littermates, we found increased spontaneous Ca 2+ activity and upregulation of purinergic receptors in OHCs from GCaMP6s Ocm -/- cochlea immediately following birth. The afferent synaptic maturation of OHCs was delayed in the absence of OCM, leading to an increased number of ribbon synapses and afferent fibers on GCaMP6s Ocm -/- OHCs before hearing onset. We propose that OCM regulates the spontaneous Ca 2+ signaling in the developing cochlea and the maturation of OHC afferent innervation.
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6
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Calcium signaling and genetic rare diseases: An auditory perspective. Cell Calcium 2023; 110:102702. [PMID: 36791536 DOI: 10.1016/j.ceca.2023.102702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/07/2023]
Abstract
Deafness is a highly heterogeneous disorder which stems, for 50%, from genetic origins. Sensory transduction relies mainly on sensory hair cells of the cochlea, in the inner ear. Calcium is key for the function of these cells and acts as a fundamental signal transduction. Its homeostasis depends on three factors: the calcium influx, through the mechanotransduction channel at the apical pole of the hair cell as well as the voltage-gated calcium channel at the base of the cells; the calcium buffering via Ca2+-binding proteins in the cytoplasm, but also in organelles such as mitochondria and the reticulum endoplasmic mitochondria-associated membranes with specialized proteins; and the calcium extrusion through the Ca-ATPase pump, located all over the plasma membrane. In addition, the synaptic transmission to the central nervous system is also controlled by calcium. Genetic studies of inherited deafness have tremendously helped understand the underlying molecular pathways of calcium signaling. In this review, we discuss these different factors in light of the associated genetic diseases (syndromic and non-syndromic deafness) and the causative genes.
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7
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Dijkstra JM, Kondo Y. Comprehensive Sequence Analysis of Parvalbumins in Fish and Their Comparison with Parvalbumins in Tetrapod Species. BIOLOGY 2022; 11:biology11121713. [PMID: 36552222 PMCID: PMC9774829 DOI: 10.3390/biology11121713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/18/2022] [Accepted: 11/19/2022] [Indexed: 11/29/2022]
Abstract
Parvalbumins are small molecules with important functions in Ca2+ signaling, but their sequence comparisons to date, especially in fish, have been relatively poor. We here, characterize sequence motifs that distinguish parvalbumin subfamilies across vertebrate species, as well as those that distinguish individual parvalbumins (orthologues) in fish, and map them to known parvalbumin structures. As already observed by others, all classes of jawed vertebrates possess parvalbumins of both the α-parvalbumin and oncomodulin subfamilies. However, we could not find convincing phylogenetic support for the common habit of classifying all non-α-parvalbumins together as "β-parvalbumins." In teleost (modern bony) fish, we here distinguish parvalbumins 1-to-10, of which the gene copy number can differ between species. The genes for α-parvalbumins (pvalb6 and pvalb7) and oncomodulins (pvalb8 and pvalb9) are well conserved between teleost species, but considerable variation is observed in their copy numbers of the non-α/non-oncomodulin genes pvalb1-to-5 and pvalb10. Teleost parvalbumins 1-to-4 are hardly distinguishable from each other and are highly expressed in muscle, and described allergens belong to this subfamily. However, in some fish species α-parvalbumin expression is also high in muscle. Pvalb5 and pvalb10 molecules form distinct lineages, the latter even predating the origin of teleosts, but have been lost in some teleost species. The present study aspires to be a frame of reference for future studies trying to compare different parvalbumins.
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Affiliation(s)
- Johannes M. Dijkstra
- Center for Medical Science, Fujita Health University, Dengaku-gakubo 1-98, Toyoake 470-1192, Japan
| | - Yasuto Kondo
- Department of Pediatrics, Fujita Health University Bantane Hospital, Otobashi 3-6-10, Nakagawa, Nagoya 454-8509, Japan
- Correspondence:
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8
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Heuermann ML, Matos S, Hamilton D, Cox BC. Regenerated hair cells in the neonatal cochlea are innervated and the majority co-express markers of both inner and outer hair cells. Front Cell Neurosci 2022; 16:841864. [PMID: 36187289 PMCID: PMC9524252 DOI: 10.3389/fncel.2022.841864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 08/29/2022] [Indexed: 11/30/2022] Open
Abstract
After a damaging insult, hair cells can spontaneously regenerate from cochlear supporting cells within the first week of life. While the regenerated cells express several markers of immature hair cells and have stereocilia bundles, their capacity to differentiate into inner or outer hair cells, and ability to form new synaptic connections has not been well-described. In addition, while multiple supporting cell subtypes have been implicated as the source of the regenerated hair cells, it is unclear if certain subtypes have a greater propensity to form one hair cell type over another. To investigate this, we used two CreER mouse models to fate-map either the supporting cells located near the inner hair cells (inner phalangeal and border cells) or outer hair cells (Deiters’, inner pillar, and outer pillar cells) along with immunostaining for markers that specify the two hair cell types. We found that supporting cells fate-mapped by both CreER lines responded early to hair cell damage by expressing Atoh1, and are capable of producing regenerated hair cells that express terminal differentiation markers of both inner and outer hair cells. The majority of regenerated hair cells were innervated by neuronal fibers and contained synapses. Unexpectedly, we also found that the majority of the laterally positioned regenerated hair cells aberrantly expressed both the outer hair cell gene, oncomodulin, and the inner hair cell gene, vesicular glutamate transporter 3 (VGlut3). While this work demonstrates that regenerated cells can express markers of both inner and outer hair cells after damage, VGlut3 expression appears to lack the tight control present during embryogenesis, which leads to its inappropriate expression in regenerated cells.
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Affiliation(s)
- Mitchell L. Heuermann
- Department of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Sophia Matos
- Department of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Deborah Hamilton
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Brandon C. Cox
- Department of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
- *Correspondence: Brandon C. Cox,
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9
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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: 0] [Impact Index Per Article: 0] [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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10
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What Is Parvalbumin for? Biomolecules 2022; 12:biom12050656. [PMID: 35625584 PMCID: PMC9138604 DOI: 10.3390/biom12050656] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 12/28/2022] Open
Abstract
Parvalbumin (PA) is a small, acidic, mostly cytosolic Ca2+-binding protein of the EF-hand superfamily. Structural and physical properties of PA are well studied but recently two highly conserved structural motifs consisting of three amino acids each (clusters I and II), which contribute to the hydrophobic core of the EF-hand domains, have been revealed. Despite several decades of studies, physiological functions of PA are still poorly known. Since no target proteins have been revealed for PA so far, it is believed that PA acts as a slow calcium buffer. Numerous experiments on various muscle systems have shown that PA accelerates the relaxation of fast skeletal muscles. It has been found that oxidation of PA by reactive oxygen species (ROS) is conformation-dependent and one more physiological function of PA in fast muscles could be a protection of these cells from ROS. PA is thought to regulate calcium-dependent metabolic and electric processes within the population of gamma-aminobutyric acid (GABA) neurons. Genetic elimination of PA results in changes in GABAergic synaptic transmission. Mammalian oncomodulin (OM), the β isoform of PA, is expressed mostly in cochlear outer hair cells and in vestibular hair cells. OM knockout mice lose their hearing after 3–4 months. It was suggested that, in sensory cells, OM maintains auditory function, most likely affecting outer hair cells’ motility mechanisms.
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11
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Au NPB, Ma CHE. Neuroinflammation, Microglia and Implications for Retinal Ganglion Cell Survival and Axon Regeneration in Traumatic Optic Neuropathy. Front Immunol 2022; 13:860070. [PMID: 35309305 PMCID: PMC8931466 DOI: 10.3389/fimmu.2022.860070] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 02/14/2022] [Indexed: 12/12/2022] Open
Abstract
Traumatic optic neuropathy (TON) refers to a pathological condition caused by a direct or indirect insult to the optic nerves, which often leads to a partial or permanent vision deficit due to the massive loss of retinal ganglion cells (RGCs) and their axonal fibers. Retinal microglia are immune-competent cells residing in the retina. In rodent models of optic nerve crush (ONC) injury, resident retinal microglia gradually become activated, form end-to-end alignments in the vicinity of degenerating RGC axons, and actively internalized them. Some activated microglia adopt an amoeboid morphology that engulf dying RGCs after ONC. In the injured optic nerve, the activated microglia contribute to the myelin debris clearance at the lesion site. However, phagocytic capacity of resident retinal microglia is extremely poor and therefore the clearance of cellular and myelin debris is largely ineffective. The presence of growth-inhibitory myelin debris and glial scar formed by reactive astrocytes inhibit the regeneration of RGC axons, which accounts for the poor visual function recovery in patients with TON. In this Review, we summarize the current understanding of resident retinal microglia in RGC survival and axon regeneration after ONC. Resident retinal microglia play a key role in facilitating Wallerian degeneration and the subsequent axon regeneration after ONC. However, they are also responsible for producing pro-inflammatory cytokines, chemokines, and reactive oxygen species that possess neurotoxic effects on RGCs. Intraocular inflammation triggers a massive influx of blood-borne myeloid cells which produce oncomodulin to promote RGC survival and axon regeneration. However, intraocular inflammation induces chronic neuroinflammation which exacerbates secondary tissue damages and limits visual function recovery after ONC. Activated retinal microglia is required for the proliferation of oligodendrocyte precursor cells (OPCs); however, sustained activation of retinal microglia suppress the differentiation of OPCs into mature oligodendrocytes for remyelination after injury. Collectively, controlled activation of retinal microglia and infiltrating myeloid cells facilitate axon regeneration and nerve repair. Recent advance in single-cell RNA-sequencing and identification of microglia-specific markers could improve our understanding on microglial biology and to facilitate the development of novel therapeutic strategies aiming to switch resident retinal microglia’s phenotype to foster neuroprotection.
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Affiliation(s)
- Ngan Pan Bennett Au
- Department of Neuroscience, City University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Chi Him Eddie Ma
- Department of Neuroscience, City University of Hong Kong, Hong Kong, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
- *Correspondence: Chi Him Eddie Ma,
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12
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The Conditioning Lesion Response in Dorsal Root Ganglion Neurons Is Inhibited in Oncomodulin Knock-Out Mice. eNeuro 2022; 9:ENEURO.0477-21.2022. [PMID: 35131866 PMCID: PMC8874952 DOI: 10.1523/eneuro.0477-21.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/20/2022] [Accepted: 01/30/2022] [Indexed: 11/21/2022] Open
Abstract
Regeneration can occur in peripheral neurons after injury, but the mechanisms involved are not fully delineated. Macrophages in dorsal root ganglia (DRGs) are involved in the enhanced regeneration that occurs after a conditioning lesion (CL), but how macrophages stimulate this response is not known. Oncomodulin (Ocm) has been proposed as a proregenerative molecule secreted by macrophages and neutrophils, is expressed in the DRG after axotomy, and stimulates neurite outgrowth by DRG neurons in culture. Wild-type (WT) and Ocm knock-out (KO) mice were used to investigate whether Ocm plays a role in the CL response in DRG neurons after sciatic nerve transection. Neurite outgrowth was measured after 24 and 48 h in explant culture 7 d after a CL. Sciatic nerve regeneration was also measured in vivo 7 d after a CL and 2 d after a subsequent sciatic nerve crush. The magnitude of the increased neurite outgrowth following a CL was significantly smaller in explants from Ocm KO mice than in explants from WT mice. In vivo after a CL, increased regeneration was found in WT animals but not in KO animals. Macrophage accumulation and levels of interleukin-6 (IL-6) mRNA were measured in axotomized DRG from WT and Ocm KO animals, and both were significantly higher than in sham-operated ganglia. At 6 h after axotomy, Il-6 mRNA was higher in WT than in Ocm KO mice. Our data support the hypothesis that Ocm plays a necessary role in producing a normal CL response and that its effects possibly result in part from stimulation of the expression of proregenerative macrophage cytokines such as IL-6.
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13
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Climer LK, Hornak AJ, Murtha K, Yang Y, Cox AM, Simpson PL, Le A, Simmons DD. Deletion of Oncomodulin Gives Rise to Early Progressive Cochlear Dysfunction in C57 and CBA Mice. Front Aging Neurosci 2021; 13:749729. [PMID: 34867279 PMCID: PMC8634891 DOI: 10.3389/fnagi.2021.749729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 10/22/2021] [Indexed: 11/13/2022] Open
Abstract
Ca2+ signaling is a major contributor to sensory hair cell function in the cochlea. Oncomodulin (OCM) is a Ca2+ binding protein (CaBP) preferentially expressed in outer hair cells (OHCs) of the cochlea and few other specialized cell types. Here, we expand on our previous reports and show that OCM delays hearing loss in mice of two different genetic backgrounds: CBA/CaJ and C57Bl/6J. In both backgrounds, genetic disruption of Ocm leads to early progressive hearing loss as measured by auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE). In both strains, loss of Ocm reduced hearing across lifetime (hearing span) by more than 50% relative to wild type (WT). Even though the two WT strains have very different hearing spans, OCM plays a considerable and similar role within their genetic environment to regulate hearing function. The accelerated age-related hearing loss (ARHL) of the Ocm KO illustrates the importance of Ca2+ signaling in maintaining hearing health. Manipulation of OCM and Ca2+ signaling may reveal important clues to the systems of function/dysfunction that lead to ARHL.
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Affiliation(s)
- Leslie K Climer
- Department of Biology, Baylor University, Waco, TX, United States
| | - Aubrey J Hornak
- Department of Biology, Baylor University, Waco, TX, United States
| | - Kaitlin Murtha
- Department of Biology, Baylor University, Waco, TX, United States
| | - Yang Yang
- Department of Biology, Baylor University, Waco, TX, United States
| | - Andrew M Cox
- Department of Biology, Baylor University, Waco, TX, United States
| | | | - Andy Le
- Department of Biology, Baylor University, Waco, TX, United States
| | - Dwayne D Simmons
- Department of Biology, Baylor University, Waco, TX, United States.,Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
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14
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Sun S, Li S, Luo Z, Ren M, He S, Wang G, Liu Z. Dual expression of Atoh1 and Ikzf2 promotes transformation of adult cochlear supporting cells into outer hair cells. eLife 2021; 10:66547. [PMID: 34477109 PMCID: PMC8439656 DOI: 10.7554/elife.66547] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 09/02/2021] [Indexed: 12/24/2022] Open
Abstract
Mammalian cochlear outer hair cells (OHCs) are essential for hearing. Severe hearing impairment follows OHC degeneration. Previous attempts at regenerating new OHCs from cochlear supporting cells (SCs) have been unsuccessful, notably lacking expression of the key OHC motor protein, Prestin. Thus, regeneration of Prestin+ OHCs represents a barrier to restore auditory function in vivo. Here, we reported the successful in vivo conversion of adult mouse cochlear SCs into Prestin+ OHC-like cells through the concurrent induction of two key transcriptional factors known to be necessary for OHC development: Atoh1 and Ikzf2. Single-cell RNA sequencing revealed the upregulation of 729 OHC genes and downregulation of 331 SC genes in OHC-like cells. The resulting differentiation status of these OHC-like cells was much more advanced than previously achieved. This study thus established an efficient approach to induce the regeneration of Prestin+ OHCs, paving the way for in vivo cochlear repair via SC transdifferentiation.
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Affiliation(s)
- Suhong Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shuting Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhengnan Luo
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Minhui Ren
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shunji He
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Guangqin Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhiyong Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
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15
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Moglie MJ, Wengier DL, Elgoyhen AB, Goutman JD. Synaptic Contributions to Cochlear Outer Hair Cell Ca 2+ Dynamics. J Neurosci 2021; 41:6812-6821. [PMID: 34253627 PMCID: PMC8360681 DOI: 10.1523/jneurosci.3008-20.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 05/30/2021] [Accepted: 07/05/2021] [Indexed: 11/21/2022] Open
Abstract
For normal cochlear function, outer hair cells (OHCs) require a precise control of intracellular Ca2+ levels. In the absence of regulatory elements such as proteinaceous buffers or extrusion pumps, OHCs degenerate, leading to profound hearing impairment. Influx of Ca2+ occurs both at the stereocilia tips and the basolateral membrane. In this latter compartment, two different origins for Ca2+ influx have been poorly explored: voltage-gated L-type Ca2+ channels (VGCCs) at synapses with Type II afferent neurons, and α9α10 cholinergic nicotinic receptors at synapses with medio-olivochlear complex (MOC) neurons. Using functional imaging in mouse OHCs, we dissected Ca2+ influx individually through each of these sources, either by applying step depolarizations to activate VGCC, or stimulating MOC axons. Ca2+ ions originated in MOC synapses, but not by VGCC activation, was confined by Ca2+-ATPases most likely present in nearby synaptic cisterns. Although Ca2+ currents in OHCs are small, VGCC Ca2+ signals were comparable in size to those elicited by α9α10 receptors, and were potentiated by ryanodine receptors (RyRs). In contrast, no evidence of potentiation by RyRs was found for MOC Ca2+ signals over a wide range of presynaptic stimulation strengths. Our study shows that despite the fact that these two Ca2+ entry sites are closely positioned, they differ in their regulation by intracellular cisterns and/or organelles, suggesting the existence of well-tuned mechanisms to separate the two different OHC synaptic functions.SIGNIFICANCE STATEMENT Outer hair cells (OHCs) are sensory cells in the inner ear operating under very special constraints. Acoustic stimulation leads to fast changes both in membrane potential and in the intracellular concentration of metabolites such as Ca2+ Tight mechanisms for Ca2+ control in OHCs have been reported. Interestingly, Ca2+ is crucial for two important synaptic processes: inhibition by efferent cholinergic neurons, and glutamate release onto Type II afferent fibers. In the current study we functionally imaged Ca2+ at these two different synapses, showing close positioning within the basolateral compartment of OHCs. In addition, we show differential regulation of these two Ca2+ sources by synaptic cisterns and/or organelles, which could result crucial for functional segregation during normal hearing.
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Affiliation(s)
- Marcelo J Moglie
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI) (Consejo Nacional de Investigaciones Científicas y Tecnológicas), Ciudad Autónoma de Buenos Aires 1428, Argentina
| | - Diego L Wengier
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI) (Consejo Nacional de Investigaciones Científicas y Tecnológicas), Ciudad Autónoma de Buenos Aires 1428, Argentina
| | - A Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI) (Consejo Nacional de Investigaciones Científicas y Tecnológicas), Ciudad Autónoma de Buenos Aires 1428, Argentina
| | - Juan D Goutman
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI) (Consejo Nacional de Investigaciones Científicas y Tecnológicas), Ciudad Autónoma de Buenos Aires 1428, Argentina
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16
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Beaulac HJ, Gilels F, Zhang J, Jeoung S, White PM. Primed to die: an investigation of the genetic mechanisms underlying noise-induced hearing loss and cochlear damage in homozygous Foxo3-knockout mice. Cell Death Dis 2021; 12:682. [PMID: 34234110 PMCID: PMC8263610 DOI: 10.1038/s41419-021-03972-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023]
Abstract
The prevalence of noise-induced hearing loss (NIHL) continues to increase, with limited therapies available for individuals with cochlear damage. We have previously established that the transcription factor FOXO3 is necessary to preserve outer hair cells (OHCs) and hearing thresholds up to two weeks following mild noise exposure in mice. The mechanisms by which FOXO3 preserves cochlear cells and function are unknown. In this study, we analyzed the immediate effects of mild noise exposure on wild-type, Foxo3 heterozygous (Foxo3+/-), and Foxo3 knock-out (Foxo3-/-) mice to better understand FOXO3's role(s) in the mammalian cochlea. We used confocal and multiphoton microscopy to examine well-characterized components of noise-induced damage including calcium regulators, oxidative stress, necrosis, and caspase-dependent and caspase-independent apoptosis. Lower immunoreactivity of the calcium buffer Oncomodulin in Foxo3-/- OHCs correlated with cell loss beginning 4 h post-noise exposure. Using immunohistochemistry, we identified parthanatos as the cell death pathway for OHCs. Oxidative stress response pathways were not significantly altered in FOXO3's absence. We used RNA sequencing to identify and RT-qPCR to confirm differentially expressed genes. We further investigated a gene downregulated in the unexposed Foxo3-/- mice that may contribute to OHC noise susceptibility. Glycerophosphodiester phosphodiesterase domain containing 3 (GDPD3), a possible endogenous source of lysophosphatidic acid (LPA), has not previously been described in the cochlea. As LPA reduces OHC loss after severe noise exposure, we treated noise-exposed Foxo3-/- mice with exogenous LPA. LPA treatment delayed immediate damage to OHCs but was insufficient to ultimately prevent their death or prevent hearing loss. These results suggest that FOXO3 acts prior to acoustic insult to maintain cochlear resilience, possibly through sustaining endogenous LPA levels.
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MESH Headings
- Animals
- Cell Death
- Disease Models, Animal
- Female
- Forkhead Box Protein O3/deficiency
- Forkhead Box Protein O3/genetics
- Gene Expression Regulation
- Hair Cells, Auditory, Outer/drug effects
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/pathology
- Hearing
- Hearing Loss, Noise-Induced/drug therapy
- Hearing Loss, Noise-Induced/genetics
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/pathology
- Homozygote
- Lysophospholipids/metabolism
- Lysophospholipids/pharmacology
- Male
- Mice, Knockout
- Noise
- Phosphoric Diester Hydrolases/genetics
- Phosphoric Diester Hydrolases/metabolism
- Time Factors
- Mice
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Affiliation(s)
- Holly J Beaulac
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - Felicia Gilels
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
- Department of Pathology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Jingyuan Zhang
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
- Department of Otolaryngology, Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston Children's Hospital Center for Life Science, Boston, MA, USA
| | - Sarah Jeoung
- University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Patricia M White
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
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17
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Mitochondrial calcium uniporter is essential for hearing and hair cell preservation in congenic FVB/NJ mice. Sci Rep 2021; 11:9660. [PMID: 33958614 PMCID: PMC8102556 DOI: 10.1038/s41598-021-88841-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/13/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial Ca2+ regulates a wide range of cell processes, including morphogenesis, metabolism, excitotoxicity, and survival. In cochlear hair cells, the activation of mechano-electrical transduction and voltage-gated Ca2+ channels result in a large influx of Ca2+. The intracellular rise in Ca2+ is partly balanced by the mitochondria which rapidly uptakes Ca2+ via a highly selective channel comprised of the main pore-forming subunit, the mitochondrial Ca2+ uniporter (MCU), and associated regulatory proteins. MCU thus contributes to Ca2+ buffering, ensuring cytosolic homeostasis, and is posited to have a critical role in hair cell function and hearing. To test this hypothesis, Ca2+ homeostasis in hair cells and cochlear function were investigated in FVB/NJ mice carrying the knockout allele of Mcu (Mcu+/− or Mcu−/−). The Mcu knockout allele, which originated in C57BL/6 strain cosegregated along with Cdh23ahl allele to the FVB/NJ strain, due to the close proximity of these genes. Neither Mcu+/− nor Mcu−/− genotypes affected cochlear development, morphology, or Ca2+ homeostasis of auditory hair cells in the first two postnatal weeks. However, Mcu−/− mice displayed high-frequency hearing impairment as early as 3 weeks postnatal, which then progressed to profound hearing loss at all frequencies in about 6 months. In Mcu+/− mice, significantly elevated ABR thresholds were observed at 6 months and 9 months of age only at 32 kHz frequency. In three-month-old Mcu−/− mice, up to 18% of the outer hair cells and occasionally some inner hair cells were missing in the mid-cochlear region. In conclusion, mitochondrial Ca2+ uniporter is not required for the development of cochlea in mice, but is essential for hearing and hair cell preservation in congenic FVB/NJ mice.
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18
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The Highly Conservative Cysteine of Oncomodulin as a Feasible Redox Sensor. Biomolecules 2021; 11:biom11010066. [PMID: 33419032 PMCID: PMC7825312 DOI: 10.3390/biom11010066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/01/2021] [Accepted: 01/03/2021] [Indexed: 11/17/2022] Open
Abstract
Oncomodulin (Ocm), or parvalbumin β, is an 11-12 kDa Ca2+-binding protein found inside and outside of vertebrate cells, which regulates numerous processes via poorly understood mechanisms. Ocm consists of two active Ca2+-specific domains of the EF-hand type ("helix-loop-helix" motif), covered by an EF-hand domain with inactive EF-hand loop, which contains a highly conservative cysteine with unknown function. In this study, we have explored peculiarities of the microenvironment of the conservative Cys18 of recombinant rat Ocm (rWT Ocm), redox properties of this residue, and structural/functional sensitivity of rWT Ocm to the homologous C18S substitution. We have found that pKa
of the Cys18 thiol lays beyond the physiological pH range. The measurement of redox dependence of rWT Ocm thiol-disulfide equilibrium (glutathione redox pair) showed that redox potential of Cys18 for the metal-free and Ca2+-loaded protein is of -168 mV and -176 mV, respectively. Therefore, the conservative thiol of rWT Ocm is prone to disulfide dimerization under physiological redox conditions. The C18S substitution drastically reduces α-helices content of the metal-free and Mg2+-bound Ocm, increases solvent accessibility of its hydrophobic residues, eliminates the cooperative thermal transition in the apo-protein, suppresses Ca2+/Mg2+ affinity of the EF site, and accelerates Ca2+ dissociation from Ocm. The distinct structural and functional consequences of the minor structural modification of Cys18 indicate its possible redox sensory function. Since some other EF-hand proteins also contain a conservative redox-sensitive cysteine located in an inactive EF-hand loop, it is reasonable to suggest that in the course of evolution, some of the EF-hands attained redox sensitivity at the expense of the loss of their Ca2+ affinity.
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19
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Lewis MA, Di Domenico F, Ingham NJ, Prosser HM, Steel KP. Hearing impairment due to Mir183/96/182 mutations suggests both loss and gain of function effects. Dis Model Mech 2020; 14:dmm.047225. [PMID: 33318051 PMCID: PMC7903918 DOI: 10.1242/dmm.047225] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/03/2020] [Indexed: 01/13/2023] Open
Abstract
The microRNA miR-96 is important for hearing, as point mutations in humans and mice result in dominant progressive hearing loss. Mir96 is expressed in sensory cells along with Mir182 and Mir183, but the roles of these closely-linked microRNAs are as yet unknown. Here we analyse mice carrying null alleles of Mir182, and of Mir183 and Mir96 together to investigate their roles in hearing. We found that Mir183/96 heterozygous mice had normal hearing and homozygotes were completely deaf with abnormal hair cell stereocilia bundles and reduced numbers of inner hair cell synapses at four weeks old. Mir182 knockout mice developed normal hearing then exhibited progressive hearing loss. Our transcriptional analyses revealed significant changes in a range of other genes, but surprisingly there were fewer genes with altered expression in the organ of Corti of Mir183/96 null mice compared with our previous findings in Mir96 Dmdo mutants, which have a point mutation in the miR-96 seed region. This suggests the more severe phenotype of Mir96 Dmdo mutants compared with Mir183/96 mutants, including progressive hearing loss in Mir96 Dmdo heterozygotes, is likely to be mediated by the gain of novel target genes in addition to the loss of its normal targets. We propose three mechanisms of action of mutant miRNAs; loss of targets that are normally completely repressed, loss of targets whose transcription is normally buffered by the miRNA, and gain of novel targets. Any of these mechanisms could lead to a partial loss of a robust cellular identity and consequent dysfunction.
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Affiliation(s)
- Morag A Lewis
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | | | - Neil J Ingham
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Haydn M Prosser
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Karen P Steel
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
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20
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Ranum PT, Goodwin AT, Yoshimura H, Kolbe DL, Walls WD, Koh JY, He DZZ, Smith RJH. Insights into the Biology of Hearing and Deafness Revealed by Single-Cell RNA Sequencing. Cell Rep 2020; 26:3160-3171.e3. [PMID: 30865901 PMCID: PMC6424336 DOI: 10.1016/j.celrep.2019.02.053] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 11/16/2018] [Accepted: 02/13/2019] [Indexed: 01/03/2023] Open
Abstract
Single-cell RNA sequencing is a powerful tool by which to characterize the transcriptional profile of low-abundance cell types, but its application to the inner ear has been hampered by the bony labyrinth, tissue sparsity, and difficulty dissociating the ultra-rare cells of the membranous cochlea. Herein, we present a method to isolate individual inner hair cells (IHCs), outer hair cells (OHCs), and Deiters' cells (DCs) from the murine cochlea at any post-natal time point. We harvested more than 200 murine IHCs, OHCs, and DCs from post-natal days 15 (p15) to 228 (p228) and leveraged both short- and long-read single-cell RNA sequencing to profile transcript abundance and structure. Our results provide insights into the expression profiles of these cells and document an unappreciated complexity in isoform variety in deafness-associated genes. This refined view of transcription in the organ of Corti improves our understanding of the biology of hearing and deafness.
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Affiliation(s)
- Paul T Ranum
- Interdisciplinary Graduate Program in Molecular & Cellular Biology, University of Iowa Graduate College, University of Iowa, Iowa City, IA 52242, USA; Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Alexander T Goodwin
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Hidekane Yoshimura
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Diana L Kolbe
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - William D Walls
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jin-Young Koh
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - David Z Z He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Richard J H Smith
- Interdisciplinary Graduate Program in Molecular & Cellular Biology, University of Iowa Graduate College, University of Iowa, Iowa City, IA 52242, USA; Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology, Head and Neck Surgery, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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21
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Tang F, Chen X, Jia L, Li H, Li J, Yuan W. Differential Gene Expression Patterns Between Apical and Basal Inner Hair Cells Revealed by RNA-Seq. Front Mol Neurosci 2020; 12:332. [PMID: 32038162 PMCID: PMC6985465 DOI: 10.3389/fnmol.2019.00332] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 12/27/2019] [Indexed: 12/27/2022] Open
Abstract
Tonotopic differences in the structure and physiological function, e.g., synapse number, membrane properties, Ca2+ channels, Ca2+ dependence of exocytosis and vesicle pool replenishment of inner hair cells (IHCs) along the longitudinal cochlear axis have recently been discovered, suggesting different gene expression patterns of IHCs. To determine whether IHCs present different gene expression patterns along the longitudinal cochlear axis, apical and basal IHCs were collected separately using the suction pipette technique from adult mouse cochleae for RNA-seq and genome-wide transcriptome analysis. We found 689 annotated genes showed more than 2-fold increase in expression. Interestingly, 93.4% of the differentially expressed genes (DEGs) was upregulated in apical IHCs. Although a subset of genes that related to IHC machinery and deafness were found to be differentially expressed, a gradient of gene expression was indeed detected in Ocm, Pvalb, Prkd1, Fbxo32, Nme2, and Sncg, which may play putative roles in the Ca2+ buffering and survival regulation. The expression of these genes was validated by real-time quantitative PCR (RT-qPCR) or immunostaining. We conclude that IHCs from different mouse cochlear longitudinal position have different gene expression profiles. Our data might serve as a valuable resource for exploring the molecular mechanisms underlying different biological properties as well as the survival regulation of IHCs.
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Affiliation(s)
- Feng Tang
- Department of Otolaryngology, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Xiaoling Chen
- Department of Otolaryngology, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Lifeng Jia
- Department of Otolaryngology, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Hai Li
- Department of Otolaryngology, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Jingya Li
- Department of Otolaryngology, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Wei Yuan
- Department of Otolaryngology, Southwest Hospital, Third Military Medical University, Chongqing, China
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22
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The Novel Peptide Vaccine GV1001 Protects Hearing in a Kanamycin-induced Ototoxicity Mouse Model. Otol Neurotol 2019; 39:e731-e737. [PMID: 30015752 DOI: 10.1097/mao.0000000000001911] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
HYPOTHESIS We tested whether GV1001 has any ototoxic side effects at different doses and whether it protects hearing in an aminoglycoside-induced ototoxicity mouse model. BACKGROUND GV1001, a novel peptide vaccine currently being examined in a Phase 3 clinical trial to treat pancreatic cancer, also has anti-inflammatory and antioxidant effects. METHODS In the first experiment, C57/BL6 mice were injected with GV1001 preparations at concentrations of 0.1 to 100 mg/kg for 7 days to evaluate the toxicity of GV1001 on the inner ear and kidneys. In the second experiment, the protective effect of GV1001 was tested in an ototoxicity mouse model that was generated by injecting 800 mg/kg kanamycin (KM) for 2 weeks. The hearing threshold and hair cell loss were compared between the KM + GV1001 group (treated with 10 mg/kg GV1001 for 2 wk) and the KM + saline group. The hearing threshold was measured before, and 7, 14, and 21 days after the initial treatment. The blood urea nitrogen level was measured. RESULTS No ototoxicity or renal toxicity was found following treatment with different doses of GV1001 (0.1-100 mg/kg). The KM + saline group showed impaired auditory function and markedly disoriented and missing cochlear hair cells, while the KM + GV1001 group showed significant hearing and hair cell preservation in comparison (p < 0.05). CONCLUSION GV1001 itself did not have any detrimental effects on the inner ear or kidney. In the KM induced ototoxicity model, concomitant administration of GV1001 protected against cochlear hair cell damage and preserve hearing.
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23
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Climer LK, Cox AM, Reynolds TJ, Simmons DD. Oncomodulin: The Enigmatic Parvalbumin Protein. Front Mol Neurosci 2019; 12:235. [PMID: 31649505 PMCID: PMC6794386 DOI: 10.3389/fnmol.2019.00235] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 09/13/2019] [Indexed: 01/21/2023] Open
Abstract
EF-hand Ca2+-binding protein family members, α- and β-parvalbumins have been studied for decades. Yet, considerable information is lacking distinguishing functional differences between mammalian α-parvalbumin (PVALB) and oncomodulin (OCM), a branded β-parvalbumin. Herein, we provide an overview detailing the current body of work centered around OCM as an EF-Hand Ca2+-binding protein and describe potential mechanisms of OCM function within the inner ear and immune cells. Additionally, we posit that OCM is evolutionarily distinct from PVALB and most other β-parvalbumins. This review summarizes recent studies pertaining to the function of OCM and emphasizes OCM as a parvalbumin possessing a unique cell and tissue distribution, Ca2+ buffering capacity and phylogenetic origin.
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Affiliation(s)
- Leslie K Climer
- Department of Biology, Baylor University, Waco, TX, United States.,Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | - Andrew M Cox
- Department of Biology, Baylor University, Waco, TX, United States.,Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | | | - Dwayne D Simmons
- Department of Biology, Baylor University, Waco, TX, United States.,Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States.,Biomedical Sciences Program, Baylor University, Waco, TX, United States
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Abstract
OBJECTIVE This review summarises the current literature on the role of microRNAs in presbyacusis (age-related hearing loss) and sudden sensorineural hearing loss. METHODS Medline, PubMed, Web of Science and Embase databases were searched for primary English-language studies, published between 2000 and 2017, which investigated the role of microRNAs in the pathogenesis of presbyacusis or sudden sensorineural hearing loss. Quality of evidence was assessed using the National Institutes of Health quality assessment tool. RESULTS Nine of 207 identified articles, 6 of good quality, satisfied the review's inclusion criteria. In presbyacusis, microRNAs in pro-apoptotic and autophagy pathways are upregulated, while microRNAs in proliferative and differentiation pathways are downregulated. Evidence for microRNAs having an aetiological role in sudden hearing loss is limited. CONCLUSION A shift in microRNA expression, leading to reduced cellular activity and impaired inner-ear homeostasis, may contribute to the pathogenesis of presbyacusis.
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25
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Takahashi S, Yamashita T, Homma K, Zhou Y, Zuo J, Zheng J, Cheatham MA. Deletion of exons 17 and 18 in prestin's STAS domain results in loss of function. Sci Rep 2019; 9:6874. [PMID: 31053797 PMCID: PMC6499820 DOI: 10.1038/s41598-019-43343-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/23/2019] [Indexed: 12/03/2022] Open
Abstract
Cochlear outer hair cells (OHC) express the motor protein, prestin, which is required for sensitivity and frequency selectivity. Because our previous work showed that a calmodulin binding site (CBS) was located in prestin's C-terminal, specifically within the intrinsically disordered region, we sought to delete the IDR to study the functional significance of calcium-dependent, calmodulin binding on OHC function. Although the construct lacking the IDR (∆IDR prestin) demonstrated wildtype-like nonlinear capacitance (NLC) in HEK293T cells, the phenotype in ∆IDR prestin knockins (KI) was similar to that in prestin knockouts: thresholds were elevated, NLC was absent and OHCs were missing from basal regions of the cochlea. Although ∆IDR prestin mRNA was measured, no prestin protein was detected. At the mRNA level, both of prestin's exons 17 and 18 were entirely removed, rather than the smaller region encoding the IDR. Our hybrid exon that contained the targeted deletion (17-18 ∆IDR) failed to splice in vitro and prestin protein lacking exons 17 and 18 aggregated and failed to target the cell membrane. Hence, the absence of prestin protein in ∆IDR KI OHCs may be due to the unexpected splicing of the hybrid 17-18 ∆IDR exon followed by rapid degradation of nonfunctional prestin protein.
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Affiliation(s)
- Satoe Takahashi
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Tetsuji Yamashita
- St. Jude Children's Research Hospital, Department of Developmental Neurobiology, Memphis, TN, USA
| | - Kazuaki Homma
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Knowles Hearing Center, Northwestern University, Evanston, IL, USA
| | - Yingjie Zhou
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, USA
| | - Jian Zuo
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, USA
| | - Jing Zheng
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Knowles Hearing Center, Northwestern University, Evanston, IL, USA
| | - Mary Ann Cheatham
- Knowles Hearing Center, Northwestern University, Evanston, IL, USA.
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, USA.
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OHC-TRECK: A Novel System Using a Mouse Model for Investigation of the Molecular Mechanisms Associated with Outer Hair Cell Death in the Inner Ear. Sci Rep 2019; 9:5285. [PMID: 30918314 PMCID: PMC6437180 DOI: 10.1038/s41598-019-41711-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 03/15/2019] [Indexed: 12/20/2022] Open
Abstract
Outer hair cells (OHCs) are responsible for the amplification of sound, and the death of these cells leads to hearing loss. Although the mechanisms for sound amplification and OHC death have been well investigated, the effects on the cochlea after OHC death are poorly understood. To study the consequences of OHC death, we established an OHC knockout system using a novel mouse model, Prestin-hDTR, which uses the prestin promoter to express the human diphtheria toxin (DT) receptor gene (hDTR). Administration of DT to adult Prestin-hDTR mice results in the depletion of almost all OHCs without significant damage to other cochlear and vestibular cells, suggesting that this system is an effective tool for the analysis of how other cells in the cochlea and vestibula are affected after OHC death. To evaluate the changes in the cochlea after OHC death, we performed differential gene expression analysis between the untreated and DT-treated groups of wild-type and Prestin-hDTR mice. This analysis revealed that genes associated with inflammatory/immune responses were significantly upregulated. Moreover, we found that several genes linked to hearing loss were strongly downregulated by OHC death. Together, these results suggest that this OHC knockout system is a useful tool to identify biomarkers associated with OHC death.
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Fettiplace R, Nam JH. Tonotopy in calcium homeostasis and vulnerability of cochlear hair cells. Hear Res 2018; 376:11-21. [PMID: 30473131 DOI: 10.1016/j.heares.2018.11.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/05/2018] [Accepted: 11/08/2018] [Indexed: 12/18/2022]
Abstract
Ototoxicity, noise overstimulation, or aging, can all produce hearing loss with similar properties, in which outer hair cells (OHCs), principally those at the high-frequency base of the cochlea, are preferentially affected. We suggest that the differential vulnerability may partly arise from differences in Ca2+ balance among cochlear locations. Homeostasis is determined by three factors: Ca2+ influx mainly via mechanotransducer (MET) channels; buffering by calcium-binding proteins and organelles like mitochondria; and extrusion by the plasma membrane CaATPase pump. We review quantification of these parameters and use our experimentally-determined values to model changes in cytoplasmic and mitochondrial Ca2+ during Ca2+ influx through the MET channels. We suggest that, in OHCs, there are two distinct micro-compartments for Ca2+ handling, one in the hair bundle and the other in the cell soma. One conclusion of the modeling is that there is a tonotopic gradient in the ability of OHCs to handle the Ca2+ load, which correlates with their vulnerability to environmental challenges. High-frequency basal OHCs are the most susceptible because they have much larger MET currents and have smaller dimensions than low-frequency apical OHCs.
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Affiliation(s)
- Robert Fettiplace
- Department of Neuroscience, University of Wisconsin, Madison, WI, 53706, USA.
| | - Jong-Hoon Nam
- Departments of Mechanical Engineering and Biomedical Engineering, University of Rochester, Rochester, NY, 14627, USA
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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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29
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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] [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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30
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In search for globally disordered apo-parvalbumins: Case of parvalbumin β-1 from coho salmon. Cell Calcium 2017; 67:53-64. [DOI: 10.1016/j.ceca.2017.08.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 08/08/2017] [Accepted: 08/31/2017] [Indexed: 11/22/2022]
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31
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Lee JK, Kim MJ. The distribution of calbindin-D28k, parvalbumin, and calretinin immunoreactivity in the inferior colliculus of circling mouse. Anat Cell Biol 2017; 50:230-238. [PMID: 29043102 PMCID: PMC5639178 DOI: 10.5115/acb.2017.50.3.230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 07/24/2017] [Accepted: 07/26/2017] [Indexed: 11/27/2022] Open
Abstract
The circling mice with tmie gene mutation are known as an animal deafness model, which showed hyperactive circling movement. Recently, the reinvestigation of circling mouse was performed to check the inner ear pathology as a main lesion of early hearing loss. In this trial, the inner ear organs were not so damaged to cause the hearing deficit of circling (cir/cir) mouse at 18 postnatal day (P18) though auditory brainstem response data indicated hearing loss of cir/cir mice at P18. Thus, another mechanism may be correlated with the early hearing loss of cir/cir mice at P18. Hearing loss in the early life can disrupt the ascending and descending information to inferior colliculus (IC) as integration site. There were many reports that hearing loss could result in the changes in Ca2+ concentration by either cochlear ablation or genetic defect. However, little was known to be reported about the correlation between the pathology of IC and Ca2+ changes in circling mice. Therefore, the present study investigated the distribution of calcium-binding proteins (CaBPs), calbindin-D28k, parvalbumin, and calretinin immunoreactivity (IR) in the IC to compare among wild-type (+/+), heterozygous (+/cir), and homozygous (cir/cir) mice by immunohistochemistry. The decreases of CaBPs IR in cir/cir were statistically significant in the neurons as well as neuropil of IC. Thus, this study proposed overall distributional alteration of CaBPs IR in the IC caused by early hearing defect and might be helpful to elucidate the pathology of central auditory disorder related with Ca2+ metabolism.
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Affiliation(s)
- Jin-Koo Lee
- Department of Pharmacology, Dankook University College of Medicine, Cheonan, Korea
| | - Myeung Ju Kim
- Department of Anatomy, Dankook University College of Medicine, Cheonan, Korea
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Modrell MS, Lyne M, Carr AR, Zakon HH, Buckley D, Campbell AS, Davis MC, Micklem G, Baker CV. Insights into electrosensory organ development, physiology and evolution from a lateral line-enriched transcriptome. eLife 2017; 6. [PMID: 28346141 PMCID: PMC5429088 DOI: 10.7554/elife.24197] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/23/2017] [Indexed: 01/22/2023] Open
Abstract
The anamniote lateral line system, comprising mechanosensory neuromasts and electrosensory ampullary organs, is a useful model for investigating the developmental and evolutionary diversification of different organs and cell types. Zebrafish neuromast development is increasingly well understood, but neither zebrafish nor Xenopus is electroreceptive and our molecular understanding of ampullary organ development is rudimentary. We have used RNA-seq to generate a lateral line-enriched gene-set from late-larval paddlefish (Polyodon spathula). Validation of a subset reveals expression in developing ampullary organs of transcription factor genes critical for hair cell development, and genes essential for glutamate release at hair cell ribbon synapses, suggesting close developmental, physiological and evolutionary links between non-teleost electroreceptors and hair cells. We identify an ampullary organ-specific proneural transcription factor, and candidates for the voltage-sensing L-type Cav channel and rectifying Kv channel predicted from skate (cartilaginous fish) ampullary organ electrophysiology. Overall, our results illuminate ampullary organ development, physiology and evolution.
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Affiliation(s)
- Melinda S Modrell
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Mike Lyne
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Adrian R Carr
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Harold H Zakon
- Department of Neuroscience, The University of Texas at Austin, Austin, United States.,Department of Integrative Biology, The University of Texas at Austin, Austin, United States
| | - David Buckley
- Departmento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales-MNCN-CSIC, Madrid, Spain.,Department of Natural Sciences, Saint Louis University - Madrid Campus, Madrid, Spain
| | - Alexander S Campbell
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Marcus C Davis
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, United States
| | - Gos Micklem
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Clare Vh Baker
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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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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34
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Global Analysis of Protein Expression of Inner Ear Hair Cells. J Neurosci 2016; 37:1320-1339. [PMID: 28039372 DOI: 10.1523/jneurosci.2267-16.2016] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 11/29/2016] [Accepted: 12/19/2016] [Indexed: 11/21/2022] Open
Abstract
The mammalian inner ear (IE) subserves auditory and vestibular sensations via highly specialized cells and proteins. Sensory receptor hair cells (HCs) are necessary for transducing mechanical inputs and stimulating sensory neurons by using a host of known and as yet unknown protein machinery. To understand the protein composition of these unique postmitotic cells, in which irreversible protein degradation or damage can lead to impaired hearing and balance, we analyzed IE samples by tandem mass spectrometry to generate an unbiased, shotgun-proteomics view of protein identities and abundances. By using Pou4f3/eGFP-transgenic mice in which HCs express GFP driven by Pou4f3, we FACS purified a population of HCs to analyze and compare the HC proteome with other IE subproteomes from sensory epithelia and whole IE. We show that the mammalian HC proteome comprises hundreds of uniquely or highly expressed proteins. Our global proteomic analysis of purified HCs extends the existing HC transcriptome, revealing previously undetected gene products and isoform-specific protein expression. Comparison of our proteomic data with mouse and human databases of genetic auditory/vestibular impairments confirms the critical role of the HC proteome for normal IE function, providing a cell-specific pool of candidates for novel, important HC genes. Several proteins identified exclusively in HCs by proteomics and verified by immunohistochemistry map to human genetic deafness loci, potentially representing new deafness genes. SIGNIFICANCE STATEMENT Hearing and balance rely on specialized sensory hair cells (HCs) in the inner ear (IE) to convey information about sound, acceleration, and orientation to the brain. Genetically and environmentally induced perturbations to HC proteins can result in deafness and severe imbalance. We used transgenic mice with GFP-expressing HCs, coupled with FACS sorting and tandem mass spectrometry, to define the most complete HC and IE proteome to date. We show that hundreds of proteins are uniquely identified or enriched in HCs, extending previous gene expression analyses to reveal novel HC proteins and isoforms. Importantly, deafness-linked proteins were significantly enriched in HCs, suggesting that this in-depth proteomic analysis of IE sensory cells may hold potential for deafness gene discovery.
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