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Fritzsch B, Kersigo J, Rejent K, Gherman W, Frank PW, Giovannucci DR, Maklad A. Hair cell morphological patterns and polarity organization in the sea lamprey vestibular cristae. Anat Rec (Hoboken) 2023. [PMID: 36651665 DOI: 10.1002/ar.25164] [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: 07/11/2022] [Revised: 12/19/2022] [Accepted: 12/23/2022] [Indexed: 01/19/2023]
Abstract
The inner ear of the sea lamprey was examined by scanning electron microscopy, antibody labeling with tubulin, Myo7a, Spectrin, and Phalloidin stain to elucidate the canal cristae organization and the morphology and polarity of the hair cells. We characterized the hair cell stereocilia bundles and their morphological polarity with respect to the kinocilia. We identified three types of hair cells. In Type 1 hair cells, the kinocilia were slightly longer than the tallest stereocilia. This type was located along the medial bank of the crista and their polarity, based on kinocilia location, was uniformly pointed ampullipetally. Type 2 hair cells that had kinocilia that were much longer than the stereocilia, were most abundant in the central region of the crista. This type of hair cell displayed variable polarity. Type 3 hair cells had extremely long kinocilia (~40-50 μm long) and with extremely short stereocilia. They were mostly located in the lateral zone crista and displayed ampullipetal polarity. Myo7a and tubulin antibodies revealed that hair cells and vestibular afferents are distributed across the canal cristae in the lamprey, covering the area of cruciate eminence; a feature that is absent in more derived vertebrates. Spectrin shows hair cells of varying polarities in the central zone. In this zone, some cells followed the main polarity vector (lateral) like those in medial and lateral zones, whereas other cells displayed polarities that carried up to 40° from the main polarity vector.
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Affiliation(s)
- Bernd Fritzsch
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Jennifer Kersigo
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Kassidy Rejent
- Department of Neurosciences, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, USA
| | - Wesley Gherman
- Department of Neurosciences, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, USA
| | - Patrick W Frank
- Department of Neurosciences, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, USA.,Department of Medical Education, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, USA
| | - David R Giovannucci
- Department of Neurosciences, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, USA.,Department of Medical Education, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, USA
| | - Adel Maklad
- Department of Neurosciences, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, USA.,Department of Medical Education, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, USA
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2
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Gu X, Jiang Q, Sun W, Guo W, Yang S. Anatomical analysis of vestibular aqueducts in humans and miniature pigs. Anat Rec (Hoboken) 2021. [DOI: 10.1002/ar.24577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Xiang Gu
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital Beijing China
- Department of Otolayngology, Head & Neck Surgery, The Tianjin Children's Hospital Tianjin P.R. China
- State Key Lab of Hearing Science Ministry of Education Beijing China
- Department of Otolaryngeal‐Head Neck Surgery, Chinese PLA General Hospital Beijing P.R. China
- Chinese PLA Medical School Beijing China
| | - Qing‐qing Jiang
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital Beijing China
- Department of Otolayngology, Head & Neck Surgery, The Tianjin Children's Hospital Tianjin P.R. China
- State Key Lab of Hearing Science Ministry of Education Beijing China
- Department of Otolaryngeal‐Head Neck Surgery, Chinese PLA General Hospital Beijing P.R. China
- Chinese PLA Medical School Beijing China
| | - Wei Sun
- Department of Communicative Disorders & Sciences, Center for Hearing and Deafness State University of New York at Buffalo New York USA
| | - Weiwei Guo
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital Beijing China
- Department of Otolayngology, Head & Neck Surgery, The Tianjin Children's Hospital Tianjin P.R. China
- State Key Lab of Hearing Science Ministry of Education Beijing China
- Department of Otolaryngeal‐Head Neck Surgery, Chinese PLA General Hospital Beijing P.R. China
- Chinese PLA Medical School Beijing China
| | - Shi‐Ming Yang
- College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital Beijing China
- Department of Otolayngology, Head & Neck Surgery, The Tianjin Children's Hospital Tianjin P.R. China
- State Key Lab of Hearing Science Ministry of Education Beijing China
- Department of Otolaryngeal‐Head Neck Surgery, Chinese PLA General Hospital Beijing P.R. China
- Chinese PLA Medical School Beijing China
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Muller M. Mechanical aspects of the semicircular ducts in the vestibular system. BIOLOGICAL CYBERNETICS 2020; 114:421-442. [PMID: 32889629 PMCID: PMC7554018 DOI: 10.1007/s00422-020-00842-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
The semicircular ducts (SCDs) of the vestibular system play an instrumental role in equilibration and rotation perception of vertebrates. The present paper is a review of quantitative approaches and shows how SCDs function. It consists of three parts. First, the biophysical mechanisms of an SCD system composed of three mutually connected ducts, allowing endolymph to flow from one duct into another one, are analysed. The flow is quantified by solving the continuity equations in conjunction with the equations of motion of the SCD hydrodynamics. This leads to mathematical expressions that are suitable for further analytical and numerical analysis. Second, analytical solutions are derived through four simplifying steps while keeping the essentials of the coupled system intact. Some examples of flow distributions for different rotations are given. Third, the focus is on the transducer function of the SCDs. The complex structure of the mechano-electrical transduction apparatus inside the ampullae is described, and the consequences for sensitivity and frequency response are evaluated. Furthermore, both the contributions of the different terms of the equations of motion and the influence of Brownian motion are analysed. Finally, size limitations, allometry and evolutionary aspects are taken into account.
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Affiliation(s)
- Mees Muller
- Experimental Zoology Group, Wageningen University, De Elst 1, 6708 WD, Wageningen, The Netherlands.
- Physical Biology Institute Momchilovtsi, Ulica Bor 56, 4750, Momchilovtsi, Bulgaria.
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Schnetz L, Pfaff C, Libowitzky E, Johanson Z, Stepanek R, Kriwet J. Morphology and evolutionary significance of phosphatic otoliths within the inner ears of cartilaginous fishes (Chondrichthyes). BMC Evol Biol 2019; 19:238. [PMID: 31888446 PMCID: PMC6937729 DOI: 10.1186/s12862-019-1568-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 12/17/2019] [Indexed: 12/02/2022] Open
Abstract
Background Chondrichthyans represent a monophyletic group of crown group gnathostomes and are central to our understanding of vertebrate evolution. Like all vertebrates, cartilaginous fishes evolved concretions of material within their inner ears to aid with equilibrium and balance detection. Up to now, these materials have been identified as calcium carbonate-bearing otoconia, which are small bio-crystals consisting of an inorganic mineral and a protein, or otoconial masses (aggregations of otoconia bound by an organic matrix), being significantly different in morphology compared to the singular, polycrystalline otolith structures of bony fishes, which are solidified bio-crystals forming stony masses. Reinvestigation of the morphological and chemical properties of these chondrichthyan otoconia revises our understanding of otolith composition and has implications on the evolution of these characters in both the gnathostome crown group, and cartilaginous fishes in particular. Results Dissections of Amblyraja radiata, Potamotrygon leopoldi, and Scyliorhinus canicula revealed three pairs of singular polycrystalline otolith structures with a well-defined morphology within their inner ears, as observed in bony fishes. IR spectroscopy identified the material to be composed of carbonate/collagen-bearing apatite in all taxa. These findings contradict previous hypotheses suggesting these otoconial structures were composed of calcium carbonate in chondrichthyans. A phylogenetic mapping using 37 chondrichthyan taxa further showed that the acquisition of phosphatic otolith structures might be widespread within cartilaginous fishes. Conclusions Differences in the size and shape of otoliths between taxa indicate a taxonomic signal within elasmobranchs. Otoliths made of carbonate/collagen-bearing apatite are reported for the first time in chondrichthyans. The intrinsic pathways to form singular, polycrystalline otoliths may represent the plesiomorphic condition for vertebrates but needs further testing. Likewise, the phosphatic composition of otoliths in early vertebrates such as cyclostomes and elasmobranchs is probably closely related to the lack of bony tissue in these groups, supporting a close relationship between skeletal tissue mineralization patterns and chemical otolith composition, underlined by physiological constraints.
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Affiliation(s)
- Lisa Schnetz
- University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham, B15 2TT, UK.
| | - Cathrin Pfaff
- University of Vienna, Faculty of Earth Sciences, Geography and Astronomy, Institute of Palaeontology, Geozentrum, Althanstraße 14, 1090, Vienna, Austria
| | - Eugen Libowitzky
- University of Vienna, Faculty of Earth Sciences, Geography and Astronomy, Institute of Mineralogy and Crystallography, Geozentrum, Althanstraße 14, 1090, Vienna, Austria
| | - Zerina Johanson
- Department of Earth Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Rica Stepanek
- University of Vienna, Faculty of Earth Sciences, Geography and Astronomy, Institute of Palaeontology, Geozentrum, Althanstraße 14, 1090, Vienna, Austria
| | - Jürgen Kriwet
- University of Vienna, Faculty of Earth Sciences, Geography and Astronomy, Institute of Palaeontology, Geozentrum, Althanstraße 14, 1090, Vienna, Austria.
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Pfaff C, Schultz JA, Schellhorn R. The vertebrate middle and inner ear: A short overview. J Morphol 2019; 280:1098-1105. [PMID: 30117612 PMCID: PMC6766920 DOI: 10.1002/jmor.20880] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 06/30/2018] [Accepted: 07/05/2018] [Indexed: 01/11/2023]
Abstract
The evolution of the various hearing adaptations is connected to major structural changes in nearly all groups of vertebrates. Besides hearing, the detection of acceleration and orientation in space are key functions of this mechanosensory system. The symposium "show me your ear - the inner and middle ear in vertebrates" held at the 11th International Congress of Vertebrate Morphology (ICVM) 2016 in Washington, DC (USA) intended to present current research addressing adaptation and evolution of the vertebrate otic region, auditory ossicles, vestibular system, and hearing physiology. The symposium aimed at an audience with interest in hearing research focusing on morphological, functional, and comparative studies. The presented talks and posters lead to the contributions of this virtual issue highlighting recent advances in the vertebrate balance and hearing system. This article serves as an introduction to the virtual issue contributions and intends to give a short overview of research papers focusing on vertebrate labyrinth and middle ear related structures in past and recent years.
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Affiliation(s)
- Cathrin Pfaff
- University of Vienna, Department of PalaeontologyViennaAustria
| | - Julia A. Schultz
- University of Chicago, Department of Organismal Biology and AnatomyChicagoIllinoisUSA
- Rheinische Friedrich‐Wilhelms‐Universität Bonn, Steinmann Institut für Geologie, Mineralogie und PaläontologieBonnGermany
| | - Rico Schellhorn
- Rheinische Friedrich‐Wilhelms‐Universität Bonn, Steinmann Institut für Geologie, Mineralogie und PaläontologieBonnGermany
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Pombal MA, Megías M. Development and Functional Organization of the Cranial Nerves in Lampreys. Anat Rec (Hoboken) 2018; 302:512-539. [DOI: 10.1002/ar.23821] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/15/2017] [Accepted: 09/17/2017] [Indexed: 02/03/2023]
Affiliation(s)
- Manuel A. Pombal
- Neurolam Group, Department of Functional Biology and Health Sciences, Faculty of Biology - IBIV; University of Vigo; Vigo, 36310 Spain
| | - Manuel Megías
- Neurolam Group, Department of Functional Biology and Health Sciences, Faculty of Biology - IBIV; University of Vigo; Vigo, 36310 Spain
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Mann ZF, Gálvez H, Pedreno D, Chen Z, Chrysostomou E, Żak M, Kang M, Canden E, Daudet N. Shaping of inner ear sensory organs through antagonistic interactions between Notch signalling and Lmx1a. eLife 2017; 6:e33323. [PMID: 29199954 PMCID: PMC5724992 DOI: 10.7554/elife.33323] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 12/02/2017] [Indexed: 12/19/2022] Open
Abstract
The mechanisms of formation of the distinct sensory organs of the inner ear and the non-sensory domains that separate them are still unclear. Here, we show that several sensory patches arise by progressive segregation from a common prosensory domain in the embryonic chicken and mouse otocyst. This process is regulated by mutually antagonistic signals: Notch signalling and Lmx1a. Notch-mediated lateral induction promotes prosensory fate. Some of the early Notch-active cells, however, are normally diverted from this fate and increasing lateral induction produces misshapen or fused sensory organs in the chick. Conversely Lmx1a (or cLmx1b in the chick) allows sensory organ segregation by antagonizing lateral induction and promoting commitment to the non-sensory fate. Our findings highlight the dynamic nature of sensory patch formation and the labile character of the sensory-competent progenitors, which could have facilitated the emergence of new inner ear organs and their functional diversification in the course of evolution.
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Affiliation(s)
- Zoe F Mann
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | - Héctor Gálvez
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | - David Pedreno
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | - Ziqi Chen
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | | | - Magdalena Żak
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | - Miso Kang
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | | | - Nicolas Daudet
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
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8
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Honda K, Kim SH, Kelly MC, Burns JC, Constance L, Li X, Zhou F, Hoa M, Kelley MW, Wangemann P, Morell RJ, Griffith AJ. Molecular architecture underlying fluid absorption by the developing inner ear. eLife 2017; 6. [PMID: 28994389 PMCID: PMC5634787 DOI: 10.7554/elife.26851] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 09/10/2017] [Indexed: 12/26/2022] Open
Abstract
Mutations of SLC26A4 are a common cause of hearing loss associated with enlargement of the endolymphatic sac (EES). Slc26a4 expression in the developing mouse endolymphatic sac is required for acquisition of normal inner ear structure and function. Here, we show that the mouse endolymphatic sac absorbs fluid in an SLC26A4-dependent fashion. Fluid absorption was sensitive to ouabain and gadolinium but insensitive to benzamil, bafilomycin and S3226. Single-cell RNA-seq analysis of pre- and postnatal endolymphatic sacs demonstrates two types of differentiated cells. Early ribosome-rich cells (RRCs) have a transcriptomic signature suggesting expression and secretion of extracellular proteins, while mature RRCs express genes implicated in innate immunity. The transcriptomic signature of mitochondria-rich cells (MRCs) indicates that they mediate vectorial ion transport. We propose a molecular mechanism for resorption of NaCl by MRCs during development, and conclude that disruption of this mechanism is the root cause of hearing loss associated with EES.
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Affiliation(s)
- Keiji Honda
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Sung Huhn Kim
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Michael C Kelly
- Developmental Neuroscience Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Joseph C Burns
- Developmental Neuroscience Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Laura Constance
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Xiangming Li
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Fei Zhou
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Michael Hoa
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Matthew W Kelley
- Developmental Neuroscience Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Philine Wangemann
- Anatomy and Physiology Department, Kansas State University, Manhattan, United States
| | - Robert J Morell
- Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Andrew J Griffith
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
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Fritzsch B, Elliott KL. Evolution and Development of the Inner Ear Efferent System: Transforming a Motor Neuron Population to Connect to the Most Unusual Motor Protein via Ancient Nicotinic Receptors. Front Cell Neurosci 2017; 11:114. [PMID: 28484373 PMCID: PMC5401870 DOI: 10.3389/fncel.2017.00114] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 04/05/2017] [Indexed: 02/06/2023] Open
Abstract
All craniate chordates have inner ears with hair cells that receive input from the brain by cholinergic centrifugal fibers, the so-called inner ear efferents (IEEs). Comparative data suggest that IEEs derive from facial branchial motor (FBM) neurons that project to the inner ear instead of facial muscles. Developmental data showed that IEEs develop adjacent to FBMs and segregation from IEEs might depend on few transcription factors uniquely associated with IEEs. Like other cholinergic terminals in the peripheral nervous system (PNS), efferent terminals signal on hair cells through nicotinic acetylcholine channels, likely composed out of alpha 9 and alpha 10 units (Chrna9, Chrna10). Consistent with the evolutionary ancestry of IEEs is the even more conserved ancestry of Chrna9 and 10. The evolutionary appearance of IEEs may reflect access of FBMs to a novel target, possibly related to displacement or loss of mesoderm-derived muscle fibers by the ectoderm-derived ear vesicle. Experimental transplantations mimicking this possible aspect of ear evolution showed that different motor neurons of the spinal cord or brainstem form cholinergic synapses on hair cells when ears replace somites or eyes. Transplantation provides experimental evidence in support of the evolutionary switch of FBM neurons to become IEEs. Mammals uniquely evolved a prestin related motor system to cause shape changes in outer hair cells regulated by the IEEs. In summary, an ancient motor neuron population drives in craniates via signaling through highly conserved Chrna receptors a uniquely derived cellular contractility system that is essential for hearing in mammals.
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10
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Choi J, Chang J, Jun HJ, Im GJ, Chae SW, Lee SH, Kwon SY, Jung HH, Chung AY, Park HC. Protective role of edaravone against neomycin-induced ototoxicity in zebrafish. J Appl Toxicol 2014; 34:554-61. [PMID: 24795994 DOI: 10.1002/jat.2964] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Aminoglycosides such as neomycin are one of the most commonly prescribed types of antibiotics worldwide. However, these drugs appear to generate free radicals within the inner ear, which can result in permanent hearing loss. We evaluated the effects of edaravone, a neuroprotective agent, on neomycin-induced ototoxicity in transgenic zebrafish. The 5-day post fertilization (dpf) zebrafish larvae were exposed to 125 μM neomycin and various concentrations of edaravone for 1 h. Hair cell survival was calculated as average numbers of the hair cells in the control group, which was not exposed to neomycin. Ultrastructural changes were evaluated using a scanning electron microscope (SEM) and transmission electron microscope (TEM). Edaravone protected against neomycin-induced hair cell loss in the neuromasts (1000 μM: 11.6 ± 1.1 cells, neomycin only: 5.5 ± 0.5 cells; n = 10, P<0.05) and decreased the TUNEL reaction for detecting apoptosis. In ultrastructural analysis, structures of mitochondria and hair cells within neuromasts were preserved in zebrafish exposed to 125 μM neomycin and 1000 μM edaravone for 1 h. Edaravone protected against neomycin-induced hair cell loss by preventing apoptosis.
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MESH Headings
- Animals
- Animals, Genetically Modified
- Antipyrine/analogs & derivatives
- Antipyrine/pharmacology
- Apoptosis/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- Edaravone
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/ultrastructure
- Hair Cells, Auditory/drug effects
- Hair Cells, Auditory/ultrastructure
- In Situ Nick-End Labeling
- Microscopy, Confocal
- Microscopy, Electron, Scanning
- Microscopy, Electron, Transmission
- Mitochondria/drug effects
- Mitochondria/ultrastructure
- Neomycin/toxicity
- Neuroprotective Agents/pharmacology
- Zebrafish/embryology
- Zebrafish/genetics
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Sienknecht UJ, Köppl C, Fritzsch B. Evolution and Development of Hair Cell Polarity and Efferent Function in the Inner Ear. BRAIN, BEHAVIOR AND EVOLUTION 2014; 83:150-61. [DOI: 10.1159/000357752] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 12/03/2013] [Indexed: 11/19/2022]
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Giari L, Dezfuli BS, Astolfi L, Martini A. Ultrastructural effects of cisplatin on the inner ear and lateral line system of zebrafish (Danio rerio) larvae. J Appl Toxicol 2011; 32:293-9. [PMID: 21590781 DOI: 10.1002/jat.1691] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 04/08/2011] [Accepted: 04/08/2011] [Indexed: 11/10/2022]
Abstract
Zebrafish, Danio rerio, has been a prominent model vertebrate for the study of chemical toxicity and human disease. Zebrafish hair cells (HCs) show significant structural, functional and molecular similarities to the mammalian inner ear HCs. We examined the effects of cisplatin, an anti-cancer drug, on HCs of the inner ear and on HCs and support cells (SCs) of neuromasts in zebrafish using transmission and scanning electron microscopy. Forty-five zebrafish larvae, 12 days post-fertilization, were assessed: 15 unexposed controls, 15 exposed to 10 µM cisplatin solution, and 15 exposed to 50 µM cisplatin solution. Hair cells in the cristae and maculae of the inner ear and of neuromasts were extremely sensitive to cisplatin. The drug was associated with vacuolization and the presence of myelinoid bodies in HC cytoplasm and with a condensation of the nuclear chromatin. The predominant pattern of injury was widespread degeneration of mitochondria, which appeared swollen and less electron-dense with disorganized or reduced cristae. Severity of damage seemed to be concentration-dependent, and the inner ear suffered more damage than the lateral line. Alterations similar to those in HCs were also observed in SCs of the neuromasts. Scanning electron microscopy showed loss of kinocilia in neuromasts of fish exposed to the higher concentration of cisplatin.
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Affiliation(s)
- Luisa Giari
- Department of Biology and Evolution, University of Ferrara, Ferrara, 44121, Italy
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14
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15
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Fritzsch B, Pauley S, Beisel KW. Cells, molecules and morphogenesis: the making of the vertebrate ear. Brain Res 2006; 1091:151-71. [PMID: 16643865 PMCID: PMC3904743 DOI: 10.1016/j.brainres.2006.02.078] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 02/15/2006] [Accepted: 02/15/2006] [Indexed: 01/19/2023]
Abstract
The development and evolution of mechanosensory cells and the vertebrate ear is reviewed with an emphasis on delineating the cellular, molecular and developmental basis of these changes. Outgroup comparisons suggests that mechanosensory cells are ancient features of multicellular organisms. Molecular evidence suggests that key genes involved in mechanosensory cell function and development are also conserved among metazoans. The divergent morphology of mechanosensory cells across phyla is interpreted here as 'deep molecular homology' that was in parallel shaped into different forms in each lineage. The vertebrate mechanosensory hair cell and its associated neuron are interpreted as uniquely derived features of vertebrates. It is proposed that the vertebrate otic placode presents a unique embryonic adaptation in which the diffusely distributed ancestral mechanosensory cells became concentrated to generate a large neurosensory precursor population. Morphogenesis of the inner ear is reviewed and shown to depend on genes expressed in and around the hindbrain that interact with the otic placode to define boundaries and polarities. These patterning genes affect downstream genes needed to maintain proliferation and to execute ear morphogenesis. We propose that fibroblast growth factors (FGFs) and their receptors (FGFRs) are a crucial central node to translate patterning into the complex morphology of the vertebrate ear. Unfortunately, the FGF and FGFR genes have not been fully analyzed in the many mutants with morphogenetic ear defects described thus far. Likewise, little information exists on the ear histogenesis and neurogenesis in many mutants. Nevertheless, a molecular mechanism is now emerging for the formation of the horizontal canal, an evolutionary novelty of the gnathostome ear. The existing general module mediating vertical canal growth and morphogenesis was modified by two sets of new genes: one set responsible for horizontal canal morphogenesis and another set for neurosensory formation of the horizontal crista and associated sensory neurons. The dramatic progress in deciphering the molecular basis of ear morphogenesis offers grounds for optimism for translational research toward intervention in human morphogenetic defects of the ear.
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Affiliation(s)
- Bernd Fritzsch
- Creighton University, Department of Biomedical Sciences, 2500 California Plaza, Omaha, NE 68178, USA.
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16
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Avallone B, Fascio U, Senatore A, Balsamo G, Bianco PG, Marmo F. The membranous labyrinth during larval development in lamprey (Lampetra planeri, Bloch, 1784). Hear Res 2005; 201:37-43. [PMID: 15721559 DOI: 10.1016/j.heares.2004.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
SEM and CLSM studies were performed on the membranous labyrinth of Lampetra planeri, a threatened species of brook lamprey, spanning from the 1st to the 4th year of ammocoetes larval stages and on the adults. In all the examined stages, the entire membranous labyrinth does not show any morphologic differences, but only a progressive increase in size. SEM and CLSM observations show that the ciliated chamber is lined with numerous unsensorial multiciliated cells. In the early stages, the ciliary bundles were approximately 15 microm long, while in the late stages they reached 30 microm. In the crista sensory area, we observed two populations of hair cells. "Type II" cells are peculiar for this species and show both long stereocilia decreasing in length and a long kinocilium (10-12 microm). Two other types of ciliary bundles have been found on the sensory hair cells of the Macula communis: the first one has both kinocilium and stereocilia about 4-5 microm long; the second shows a long kinocilium (7-10 microm in length) and short stereocilia bundles with a gradual increase in length. In the early stages of development, the three macular areas show few and sparsely distributed hair cells. In the late developmental stages, hair cells become more numerous and densely populated.
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Affiliation(s)
- Bice Avallone
- Department of Genetics, General and Molecular Biology, University of Naples Federico II, Naples, Italy
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Abstract
This paper considers aspects of the evolution of the vertebrate auditory system from an 'ichthyocentric' perspective. It is argued that all vertebrate auditory systems are required to do certain basic tasks including acoustic feature discrimination, sound source localization, frequency analysis, and auditory scene analysis, among others. These sorts of capabilities arose very early in the evolution of the vertebrates and have been modified by selection in different species. In some cases the same structures have been involved in detection and analysis throughout the vertebrates, while in other cases the mechanism by which the same type of analysis takes place may have changed.
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Affiliation(s)
- R R Fay
- Department of Psychology and Parmly Hearing Institute, Loyola University of Chicago, Chicago, IL 60626, USA
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