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Werner M, Van De Water TR, Stenlund H, Berggren D. Ultrastructural Characterization of Stem Cell-Derived Replacement Vestibular Hair Cells Within Ototoxin-Damaged Rat Utricle Explants. Anat Rec (Hoboken) 2019; 303:506-515. [PMID: 31090209 PMCID: PMC7065082 DOI: 10.1002/ar.24148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 08/23/2018] [Accepted: 09/07/2018] [Indexed: 11/25/2022]
Abstract
The auditory apparatus of the inner ear does not show turnover of sensory hair cells (HCs) in adult mammals; in contrast, there are many observations supporting low‐level turnover of vestibular HCs within the balance organs of mammalian inner ears. This low‐level renewal of vestibular HCs exists during normal conditions and it is further enhanced after trauma‐induced loss of these HCs. The main process for renewal of HCs within mammalian vestibular epithelia is a conversion/transdifferentiation of existing supporting cells (SCs) into replacement HCs.In earlier studies using long‐term organ cultures of postnatal rat macula utriculi, HC loss induced by gentamicin resulted in an initial substantial decline in HC density followed by a significant increase in the proportion of HCs to SCs indicating the production of replacement HCs. In the present study, using the same model of ototoxic damage to study renewal of vestibular HCs, we focus on the ultrastructural characteristics of SCs undergoing transdifferentiation into new HCs. Our objective was to search for morphological signs of SC plasticity during this process. In the utricular epithelia, we observed immature HCs, which appear to be SCs transdifferentiating into HCs. These bridge SCs have unique morphological features characterized by formation of foot processes, basal accumulation of mitochondria, and an increased amount of connections with nearby SCs. No gap junctions were observed on these transitional cells. The tight junction seals were morphologically intact in both control and gentamicin‐exposed explants. Anat Rec, 303:506–515, 2020. © 2019 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.
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Affiliation(s)
- Mimmi Werner
- Department of Clinical Sciences, Otolaryngology, University of Umeå, Umeå, Sweden
| | - Thomas R Van De Water
- Cochlear Implant Research Program, Department of Otolaryngology, University of Miami Ear Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Hans Stenlund
- Department of Epidemiology and Global Health, University of Umeå, Umeå, Sweden
| | - Diana Berggren
- Department of Clinical Sciences, Otolaryngology, University of Umeå, Umeå, Sweden
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Ladrech S, Eybalin M, Puel JL, Lenoir M. Epithelial-mesenchymal transition, and collective and individual cell migration regulate epithelial changes in the amikacin-damaged organ of Corti. Histochem Cell Biol 2017; 148:129-142. [PMID: 28365859 DOI: 10.1007/s00418-017-1548-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2017] [Indexed: 12/23/2022]
Abstract
Characterizing the microenvironment of a damaged organ of Corti and identifying the basic mechanisms involved in subsequent epithelial reorganization are critical for improving the outcome of clinical therapies. In this context, we studied the expression of a variety of cell markers related to cell shape, cell adhesion and cell plasticity in the rat organ of Corti poisoned with amikacin. Our results indicate that, after severe outer hair cell losses, the cytoarchitectural reorganization of the organ of Corti implicates epithelial-mesenchymal transition mechanisms and involves both collective and individual cell migratory processes. The results also suggest that both root cells and infiltrated fibroblasts participate in the homeostasis of the damaged epithelium, and that the flat epithelium that may emerge offers biological opportunities for late regenerative therapies.
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Affiliation(s)
- Sabine Ladrech
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital Saint Eloi, 80 rue Augustin Fliche, 34091, Montpellier Cedex 5, France.,University of Montpellier, Montpellier, France
| | - Michel Eybalin
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital Saint Eloi, 80 rue Augustin Fliche, 34091, Montpellier Cedex 5, France.,University of Montpellier, Montpellier, France
| | - Jean-Luc Puel
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital Saint Eloi, 80 rue Augustin Fliche, 34091, Montpellier Cedex 5, France.,University of Montpellier, Montpellier, France
| | - Marc Lenoir
- INSERM U1051, Institut des Neurosciences de Montpellier, Hôpital Saint Eloi, 80 rue Augustin Fliche, 34091, Montpellier Cedex 5, France. .,University of Montpellier, Montpellier, France.
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The postnatal accumulation of junctional E-cadherin is inversely correlated with the capacity for supporting cells to convert directly into sensory hair cells in mammalian balance organs. J Neurosci 2011; 31:11855-66. [PMID: 21849546 DOI: 10.1523/jneurosci.2525-11.2011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mammals experience permanent impairments from hair cell (HC) losses, but birds and other non-mammals quickly recover hearing and balance senses after supporting cells (SCs) give rise to replacement HCs. Avian HC epithelia express little or no E-cadherin, and differences in the thickness of F-actin belts at SC junctions strongly correlate with different species' capacities for HC replacement, so we investigated junctional cadherins in human and murine ears. We found strong E-cadherin expression at SC-SC junctions that increases more than sixfold postnatally in mice. When we cultured utricles from young mice with γ-secretase inhibitors (GSIs), striolar SCs completely internalized their E-cadherin, without affecting N-cadherin. Hes and Hey expression also decreased and the SCs began to express Atoh1. After 48 h, those SCs expressed myosins VI and VIIA, and by 72 h, they developed hair bundles. However, some scattered striolar SCs retained E-cadherin and the SC phenotype. In extrastriolar regions, the vast majority of SCs also retained E-cadherin and failed to convert into HCs even after long GSI treatments. Microscopic measurements revealed that the junctions between extrastriolar SCs were more developed than those between striolar SCs. In GSI-treated utricles as old as P12, differentiated striolar SCs converted into HCs, but such responses declined with age and ceased by P16. Thus, temporal and spatial differences in postnatal SC-to-HC phenotype conversion capacity are linked to the structural attributes of E-cadherin containing SC junctions in mammals, which differ substantially from their counterparts in non-mammalian vertebrates that readily recover from hearing and balance deficits through hair cell regeneration.
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Zhao H, Peng H, Cai SX, Li W, Zou F, Tong W. Toluene diisocyanate enhances human bronchial epithelial cells' permeability partly through the vascular endothelial growth factor pathway. Clin Exp Allergy 2009; 39:1532-9. [PMID: 19624533 DOI: 10.1111/j.1365-2222.2009.03300.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Toluene diisocyanate (TDI) is a recognized chemical asthmogen; yet, the mechanisms of its toxicity have not been elucidated. OBJECTIVE To investigate the influence of TDI on the permeability of human bronchial epithelial cell (HBE; HBE135-E6E7) monolayers in vitro, and the expression of vascular endothelial growth factor (VEGF) in these cells. METHODS TDI-human serum albumin (HSA) conjugates were prepared by a modification of Son's method. Fluorescein isothiocyanate-labelled dextran and transmission electron microscopy were used to evaluate the effects of TDI-HSA on HBE135-E6E7 permeability. RT-PCR and ELISA were used to evaluate VEGF gene expression and protein release from HBE135-E6E7 cells stimulated by TDI-HSA. A VEGF-neutralizing antibody was used in monolayer permeability experiments to determine the role of the VEGF pathway in this process. RESULTS TDI-HSA significantly increased the permeability coefficients of HBE135-E6E7 monolayers (P<0.01). TDI-HSA treatment significantly increased the expression of VEGF165 and VEGF189 genes (P<0.01). ELISA showed that TDI significantly induces VEGF release from HBE135-E6E7 cells. Cells treated with TDI-HSA and VEGF-neutralizing antibody had significantly lower permeability coefficients than cells treated with TDI-HSA only (P<0.01), but still significantly higher than control cells (P<0.01). Cells treated with TDI-HSA had fewer tight junctions (TJs) than control and HSA-treated cells, and addition of the anti-VEGF antibody did not restore the original number of TJs. CONCLUSION TDI increases the permeability of HBE cell monolayers, partly through a VEGF-mediated pathway. This suggests the importance of VEGF in TDI-induced pulmonary diseases, but shows that other pathways may be involved in the pathogenic process.
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Affiliation(s)
- H Zhao
- Chronic Airways Diseases Laboratory, Department of Respiration, Nanfang Hospital, Southern Medical University, Guangzhou, China
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Parzefall B, Schmahl W, Blutke A, Baiker K, Matiasek K. A rapid approach to ultrastructural evaluation and DNA analysis of the vestibular labyrinth and ganglion in dogs and cats. J Neurosci Methods 2009; 177:217-24. [DOI: 10.1016/j.jneumeth.2008.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 09/29/2008] [Accepted: 10/02/2008] [Indexed: 01/18/2023]
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Burns JC, Burns J, Christophel JJ, Collado MS, Magnus C, Carfrae M, Corwin JT. Reinforcement of cell junctions correlates with the absence of hair cell regeneration in mammals and its occurrence in birds. J Comp Neurol 2008; 511:396-414. [PMID: 18803241 DOI: 10.1002/cne.21849] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Debilitating hearing and balance deficits often arise through damage to the inner ear's hair cells. For humans and other mammals, such deficits are permanent, but nonmammalian vertebrates can quickly recover hearing and balance through their innate capacity to regenerate hair cells. The biological basis for this difference has remained unknown, but recent investigations in wounded balance epithelia have shown that proliferation follows cellular spreading at sites of injury. As mammalian ears mature during the first weeks after birth, the capacity for spreading and proliferation declines sharply. In seeking the basis for those declines, we investigated the circumferential bands of F-actin that bracket the apical junctions between supporting cells in the gravity-sensitive utricle. We found that those bands grow much thicker as mice and humans mature postnatally, whereas their counterparts in chickens remain thin from hatching through adulthood. When we cultured utricular epithelia from chickens, we found that cellular spreading and proliferation both continued at high levels, even in the epithelia from adults. In contrast, the substantial reinforcement of the circumferential F-actin bands in mammals coincides with the steep declines in cell spreading and production established in earlier experiments. We propose that the presence of thin F-actin bands at the junctions between avian supporting cells may contribute to the lifelong persistence of their capacity for shape change, cell proliferation, and hair cell replacement and that the postnatal reinforcement of the F-actin bands in maturing humans and other mammals may have an important role in limiting hair cell regeneration.
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Affiliation(s)
- Joseph C Burns
- Department of Biomedical Engineering, University of Virginia School of Engineering and Applied Science, Charlottesville, Virginia 22908, USA.
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Okano T, Nakagawa T, Kita T, Kada S, Yoshimoto M, Nakahata T, Ito J. Bone marrow-derived cells expressing Iba1 are constitutively present as resident tissue macrophages in the mouse cochlea. J Neurosci Res 2008; 86:1758-67. [PMID: 18253944 DOI: 10.1002/jnr.21625] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Immune-mediated inner ear disorder has been well established as a clinical entity; however, the innate immune system of the inner ear is a poorly understood area of research with high clinical and immunological importance. Although the presence of resident tissue macrophages in the inner ear has been suggested, there has been some controversy. In this study, we analyzed the origin of cochlear resident macrophages and the contribution of hematopoietic bone marrow (BM) to the recruitment of macrophages in the cochlea. To visualize the localization of BM-derived cells, BM chimeric mice were made by transplantation of hematopoietic stem cells, which were genetically labeled with enhanced green fluorescent protein, into lethally irradiated C57BL/6 mice. The distribution and characteristics of BM-derived cells in the mouse cochlea were studied immunohistochemically. We successfully identified the constitutive presence of tissue resident macrophages in the spiral ligament and spiral ganglion that are derived from BM in larger numbers than previously reported. Moreover, cochlear resident macrophages gradually turn over for several months during steady-state replacement by BM-derived cells, and the number of cochlear macrophages immediately increased in response to local surgical stress. The present findings demonstrate the hematopoietic origin of cochlear resident and infiltrating macrophages. Our study provides a novel anatomical and immunological basis for the inner ear and indicates that the cochlear resident macrophages would be a therapeutic target in inner ear disorders.
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Affiliation(s)
- Takayuki Okano
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Warchol ME. Characterization of supporting cell phenotype in the avian inner ear: implications for sensory regeneration. Hear Res 2006; 227:11-8. [PMID: 17081713 DOI: 10.1016/j.heares.2006.08.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 04/26/2006] [Accepted: 08/30/2006] [Indexed: 10/24/2022]
Abstract
The avian inner ear possesses a remarkable capacity for the regeneration of sensory receptors after acoustic trauma or ototoxicity. Most replacement hair cells are created by renewed cell division within the sensory epithelium, although some new hair cells may also arise through nonmitotic mechanisms. Current data indicate that epithelial supporting cells play an essential role in regeneration, by serving as progenitor cells. In order to become progenitors, however, supporting cells may need to undergo partial dedifferentiation. In this review, I describe molecules that are expressed by supporting cells in the avian ear. Although a number of these molecules are likely to be critical to the maintenance of the supporting cell phenotype, we presently know very little about phenotypic changes in supporting cells during the early phase of regeneration.
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Affiliation(s)
- Mark E Warchol
- Department of Otolaryngology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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Severinsen SA, Kirkegaard M, Nyengaard JR. 2,3-Dihydroxybenzoic acid attenuates kanamycin-induced volume reduction in mouse utricular type I hair cells. Hear Res 2006; 212:99-108. [PMID: 16377109 DOI: 10.1016/j.heares.2005.10.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 10/26/2005] [Indexed: 10/25/2022]
Abstract
The aminoglycoside kanamycin is a commonly used antibiotic, but unfortunately it is oto- and nephrotoxic in large doses. The negative effects are thought to be due to the formation of free radicals which is why strong antioxidants and iron chelators like 2,3-dihydroxybenzoic acid (DHB) are of great interest. This study estimates cellular quantitative changes in the utricular macula of mice following systemic treatment with kanamycin alone or in combination with DHB. The animals were injected with either saline, kanamycin or kanamycin + DHB for 15 days and perfusion fixed three weeks after last injection. Total volume of the utricle, as well as total number of hair and supporting cells, were estimated on light microscopic sections. Total volume and mean volume of hair cell types I and II and supporting cells were estimated on digital transmission electron micrographs. Total volume of the utricular macula, hair cell type I and supporting cells decreased significantly in animals injected with kanamycin but not in animals co-treated with DHB. Hair and supporting cell numbers remained unchanged in all three groups. In conclusion, the kanamycin-induced volume reduction of type I hair cells was attenuated by DHB.
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MESH Headings
- Animals
- Anti-Bacterial Agents/adverse effects
- Antioxidants/pharmacology
- Drug Therapy, Combination
- Female
- Hair Cells, Auditory/drug effects
- Hair Cells, Auditory/pathology
- Hair Cells, Auditory/ultrastructure
- Hearing Loss, Sensorineural/chemically induced
- Hearing Loss, Sensorineural/prevention & control
- Hydroxybenzoates/pharmacology
- Image Processing, Computer-Assisted
- Iron Chelating Agents/pharmacology
- Kanamycin/adverse effects
- Mice
- Mice, Inbred BALB C
- Microscopy, Electron, Transmission
- Saccule and Utricle/drug effects
- Saccule and Utricle/pathology
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Affiliation(s)
- Stig A Severinsen
- Stereology and Electron Microscopy Research Laboratory and MIND Center, Institute of Clinical Medicine, Building 1185, University of Aarhus, 8000 Aarhus C, Denmark.
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