Effect of hypodynamia on structure of vestibular apparatus in Japanese quail chicks: light microscopy

The model for studying the effects of simulated microgravity on the bird organism is hypodynamia. The aim of this study was to investigate the influence of chronic hypodynamia on the structure of the vestibular apparatus in Japanese quail by light microscopy. Morphological changes in the sensory epithelium of chicks reared under hypodynamia from 1 to 42 days of age were evaluated. The differences of shape and arrangement of hair cells in sensory epithelium macula utriculi and the dilatations on their basal parts were found in birds exposed to hypodynamia on day 14 and 42 compared to control. The results confirmed that hypodynamia has specific impact on developmental processes in Japanese quail and indicated that similar damage of inner ear sensory epithelium could be developed in chicks hatched and reared in conditions of real weightlessness during the space flight.

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Ionic Currents and Electromotility in Inner Ear Hair Cells From Humans

Journal of Neurophysiology ◽

10.1152/jn.1998.79.4.2235 ◽

1998 ◽

Vol 79 (4) ◽

pp. 2235-2239 ◽

Cited By ~ 22

Author(s):

John S. Oghalai ◽

Jeffrey R. Holt ◽

Takashi Nakagawa ◽

Thomas M. Jung ◽

Newton J. Coker ◽

...

Keyword(s):

Inner Ear ◽

Hair Cells ◽

Ionic Currents ◽

Sensory Epithelium ◽

Outer Hair Cells ◽

Sensory Receptor ◽

Surgical Removal ◽

Type I ◽

Vestibular Hair Cells ◽

Sensory Receptor Cells

Oghalai, John S., Jeffrey R. Holt, Takashi Nakagawa, Thomas M. Jung, Newton J. Coker, Herman A. Jenkins, Ruth Anne Eatock, and William E. Brownell. Ionic currents and electromotility in inner ear hair cells from humans. J. Neurophysiol. 79: 2235–2239, 1998. The upright posture and rich vocalizations of primates place demands on their senses of balance and hearing that differ from those of other animals. There is a wealth of behavioral, psychophysical, and CNS measures characterizing these senses in primates, but no prior recordings from their inner ear sensory receptor cells. We harvested human hair cells from patients undergoing surgical removal of life-threatening brain stem tumors and measured their ionic currents and electromotile responses. The hair cells were either isolated or left in situ in their sensory epithelium and investigated using the tight-seal, whole cell technique. We recorded from both type I and type II vestibular hair cells under voltage clamp and found four voltage-dependent currents, each of which has been reported in hair cells of other animals. Cochlear outer hair cells demonstrated electromotility in response to voltage steps like that seen in rodent animal models. Our results reveal many qualitative similarities to hair cells obtained from other animals and justify continued investigations to explore quantitative differences that may be associated with normal or pathological human sensation.

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Developing inner ear sensory neurons require TrkB and TrkC receptors for innervation of their peripheral targets

Development ◽

10.1242/dev.121.10.3381 ◽

1995 ◽

Vol 121 (10) ◽

pp. 3381-3391 ◽

Cited By ~ 9

Author(s):

T. Schimmang ◽

L. Minichiello ◽

E. Vazquez ◽

I. San Jose ◽

F. Giraldez ◽

...

Keyword(s):

Inner Ear ◽

Hair Cells ◽

Catalytic Domain ◽

Sensory System ◽

Sensory Epithelium ◽

Outer Hair Cells ◽

Developmental Study ◽

Inner Hair Cells ◽

Vestibular Neurons ◽

Cochlear Neurons

The trkB and trkC genes are expressed during the formation of the vestibular and auditory system. To elucidate the function of trkB and trkC during this process, we have analysed mice carrying a germline mutation in the tyrosine kinase catalytic domain of these genes. Neuroanatomical analysis of homozygous mutant mice revealed neuronal deficiencies in the vestibular and cochlear ganglia. In trkB (−/−) animals vestibular neurons and a subset of cochlear neurons responsible for the innervation of outer hair cells were drastically reduced. The peripheral targets of the respective neurons showed severe innervation defects. A comparative analysis of ganglia from trkC (−/−) mutants revealed a moderate reduction of vestibular neurons and a specific loss of cochlear neurons innervating inner hair cells. No nerve fibres were detected in the sensory epithelium containing inner hair cells. A developmental study of trkB (−/−) and trkC (−/−) mice showed that some vestibular and cochlear fibres initially reached their peripheral targets but failed to maintain innervation and degenerated. TrkB and TrkC receptors are therefore required for the survival of specific neuronal populations and the maintenance of target innervation in the peripheral sensory system of the inner ear.

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Early appearance of key transcription factors influence the spatiotemporal development of the human inner ear

Cell and Tissue Research ◽

10.1007/s00441-019-03115-6 ◽

2019 ◽

Vol 379 (3) ◽

pp. 459-471 ◽

Cited By ~ 1

Author(s):

Lejo Johnson Chacko ◽

Consolato Sergi ◽

Theresa Eberharter ◽

Jozsef Dudas ◽

Helge Rask-Andersen ◽

...

Keyword(s):

Transcription Factors ◽

Inner Ear ◽

Hair Cells ◽

Transforming Growth Factor ◽

Expression Patterns ◽

Organ Of Corti ◽

Sensory Epithelium ◽

Receptor Expression ◽

Cell Phenotype ◽

Type I

AbstractExpression patterns of transcription factors leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), transforming growth factor-β-activated kinase-1 (TAK1), SRY (sex-determining region Y)-box 2 (SOX2), and GATA binding protein 3 (GATA3) in the developing human fetal inner ear were studied between the gestation weeks 9 and 12. Further development of cochlear apex between gestational weeks 11 and 16 (GW11 and GW16) was examined using transmission electron microscopy. LGR5 was evident in the apical poles of the sensory epithelium of the cochlear duct and the vestibular end organs at GW11. Immunostaining was limited to hair cells of the organ of Corti by GW12. TAK1 was immune positive in inner hair cells of the organ of Corti by GW12 and colocalized with p75 neurotrophic receptor expression. Expression for SOX2 was confined primarily to the supporting cells of utricle at the earliest stage examined at GW9. Intense expression for GATA3 was presented in the cochlear sensory epithelium and spiral ganglia at GW9. Expression of GATA3 was present along the midline of both the utricle and saccule in the zone corresponding to the striolar reversal zone where the hair cell phenotype switches from type I to type II. The spatiotemporal gradient of the development of the organ of Corti was also evident with the apex of the cochlea forming by GW16. It seems that highly specific staining patterns of several transcriptions factors are critical in guiding the genesis of the inner ear over development. Our findings suggest that the spatiotemporal gradient in cochlear development extends at least until gestational week 16.

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Aquaporin-6 Expression in the Cochlear Sensory Epithelium Is Downregulated by Salicylates

Journal of Biomedicine and Biotechnology ◽

10.1155/2010/264704 ◽

2010 ◽

Vol 2010 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Paola Perin ◽

Simona Tritto ◽

Laura Botta ◽

Jacopo Maria Fontana ◽

Giulia Gastaldi ◽

...

Keyword(s):

Inner Ear ◽

Expression Pattern ◽

Hair Cells ◽

Organ Of Corti ◽

Sensory Epithelium ◽

Outer Hair Cells ◽

Rt Pcr ◽

Supporting Cells ◽

Sensory Epithelia ◽

Mechanical Compliance

We characterize the expression pattern of aquaporin-6 in the mouse inner ear by RT-PCR and immunohistochemistry. Our data show that in the inner ear aquaporin-6 is expressed, in both vestibular and acoustic sensory epithelia, by the supporting cells directly contacting hair cells. In particular, in the Organ of Corti, expression was strongest in Deiters' cells, which provide both a mechanical link between outer hair cells (OHCs) and the Organ of Corti, and an entry point for ion recycle pathways. Since aquaporin-6 is permeable to both water and anions, these results suggest its possible involvement in regulating OHC motility, directly through modulation of water and chloride flow or by changing mechanical compliance in Deiters' cells. In further support of this role, treating mice with salicylates, which impair OHC electromotility, dramatically reduced aquaporin-6 expression in the inner ear epithelia but not in control tissues, suggesting a role for this protein in modulating OHCs' responses.

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The Differentiation of Stem/Progenitor Cells Derived from the Cochlear Sensory Epithelium into Hair Cells Requires a Specific Spatial Supporting Structure of p27kip1-Positive Cells

10.21203/rs.3.rs-27324/v1 ◽

2020 ◽

Author(s):

Xianren Wang ◽

Xuemei Zhang ◽

Di Jiang ◽

Danqing Liu ◽

Hongyan Jiang

Keyword(s):

Hair Cell ◽

Progenitor Cells ◽

Hair Cells ◽

Hollow Sphere ◽

Morphological Changes ◽

Hollow Spheres ◽

Solid Sphere ◽

Sensory Epithelium ◽

Adherent Culture ◽

Epithelial Sheets

Abstract Background: Cochlear sensory epithelium-derived progenitor cells initially give rise to compact solid/round spheres. These compact solid/round spheres then gradually convert into irregular and partially hollow spheres, which then ultimately transform into large hollow spheres. The purpose of this study was to observe the differentiation of cochlear sensory epithelium-derived progenitor cells into spheres, and determine factors necessary for their development into hair cells.Methods: Cochlear epithelial sheets from postnatal day 1 C57BL/6 mice were dissociated and sphere cells were cultured. The morphological changes of the spheres were observed, and the different types of sphere cells were examined for their ability to differentiate into hair cell-like cells.Results: Solid spheres formed first, and then gradually transformed into hollow spheres over approximately 260 hours. Adherent culture and Transwell culture assays, and immunohistochemistry staining revealed that neither solid nor hollow sphere cells alone could differentiate into mature hair cells. Solid sphere cells, however, were able to differentiate into mature hair cells when co-cultured with p27kip1-positive hollow sphere cells. Direct contact of the cells was necessary for the differentiation of the solid sphere cells into mature hair cell-like cells.Conclusions: Cochlear sensory epithelium-derived progenitor cells require specific conditions to differentiate into mature hair cells.

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Research Progress on Flat Epithelium of the Inner Ear

Physiological Research ◽

10.33549/physiolres.934447 ◽

2020 ◽

pp. 775-785

Author(s):

L HE ◽

J-Y GUO ◽

K LIU ◽

G-P WANG ◽

S-S GONG

Keyword(s):

Hearing Loss ◽

Sensorineural Hearing Loss ◽

Inner Ear ◽

Hair Cells ◽

Noise Exposure ◽

Sensory Epithelium ◽

Sensorineural Hearing ◽

Research Progress ◽

Supporting Cells ◽

Mesenchymal Transition

Sensorineural hearing loss and vertigo, resulting from lesions in the sensory epithelium of the inner ear, have a high incidence worldwide. The sensory epithelium of the inner ear may exhibit extreme degeneration and is transformed to flat epithelium (FE) in humans and mice with profound sensorineural hearing loss and/or vertigo. Various factors, including ototoxic drugs, noise exposure, aging, and genetic defects, can induce FE. Both hair cells and supporting cells are severely damaged in FE, and the normal cytoarchitecture of the sensory epithelium is replaced by a monolayer of very thin, flat cells of irregular contour. The pathophysiologic mechanism of FE is unclear but involves robust cell division. The cellular origin of flat cells in FE is heterogeneous; they may be transformed from supporting cells that have lost some features of supporting cells (dedifferentiation) or may have migrated from the flanking region. The epithelial-mesenchymal transition may play an important role in this process. The treatment of FE is challenging given the severe degeneration and loss of both hair cells and supporting cells. Cochlear implant or vestibular prosthesis implantation, gene therapy, and stem cell therapy show promise for the treatment of FE, although many challenges remain to be overcome.

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The role of Math1 in inner ear development: Uncoupling the establishment of the sensory primordium from hair cell fate determination

Development ◽

10.1242/dev.129.10.2495 ◽

2002 ◽

Vol 129 (10) ◽

pp. 2495-2505 ◽

Cited By ~ 4

Author(s):

Ping Chen ◽

Jane E. Johnson ◽

Huda Y. Zoghbi ◽

Neil Segil

Keyword(s):

Hair Cell ◽

Inner Ear ◽

Cell Fate ◽

Hair Cells ◽

Organ Of Corti ◽

Sensory Epithelium ◽

Proliferating Cells ◽

Sensory Hair ◽

Sensory Hair Cells ◽

Hair Cell Differentiation

During embryonic development of the inner ear, the sensory primordium that gives rise to the organ of Corti from within the cochlear epithelium is patterned into a stereotyped array of inner and outer sensory hair cells separated from each other by non-sensory supporting cells. Math1, a close homolog of the Drosophila proneural gene atonal, has been found to be both necessary and sufficient for the production of hair cells in the mouse inner ear. Our results indicate that Math1 is not required to establish the postmitotic sensory primordium from which the cells of the organ of Corti arise, but instead is limited to a role in the selection and/or differentiation of sensory hair cells from within the established primordium. This is based on the observation that Math1 is only expressed after the appearance of a zone of non-proliferating cells that delineates the sensory primordium within the cochlear anlage. The expression of Math1 is limited to a subpopulation of cells within the sensory primordium that appear to differentiate exclusively into hair cells as the sensory epithelium matures and elongates through a process that probably involves radial intercalation of cells. Furthermore, mutation of Math1 does not affect the establishment of this postmitotic sensory primordium, even though the subsequent generation of hair cells is blocked in these mutants. Finally, in Math1 mutant embryos, a subpopulation of the cells within the sensory epithelium undergo apoptosis in a temporal gradient similar to the basal-to-apical gradient of hair cell differentiation that occurs in the cochlea of wild-type animals.

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Requirement for Brn-3c in maturation and survival, but not in fate determination of inner ear hair cells

Development ◽

10.1242/dev.125.20.3935 ◽

1998 ◽

Vol 125 (20) ◽

pp. 3935-3946 ◽

Cited By ~ 8

Author(s):

M. Xiang ◽

W.Q. Gao ◽

T. Hasson ◽

J.J. Shin

Keyword(s):

Hair Cell ◽

Inner Ear ◽

Hair Cells ◽

Cell Loss ◽

Supporting Cell ◽

Sensory Epithelium ◽

Cell Phenotype ◽

Sensory Epithelia ◽

Vestibular Sensory Epithelia ◽

And Migration

Mutations in the POU domain gene Brn-3c causes hearing impairment in both the human and mouse as a result of inner ear hair cell loss. We show here that during murine embryogenesis, Brn-3c is expressed in postmitotic cells committed to hair cell phenotype but not in mitotic progenitors in the inner ear sensory epithelium. In developing auditory and vestibular sensory epithelia of Brn-3c−/− mice, hair cells are found to be generated and undergo initial differentiation as indicated by their morphology, laminar position and expression of hair cell markers, including myosins VI and VIIa, calretinin and parvalbumin. However, a small number of hair cells are anomalously retained in the supporting cell layer in the vestibular sensory epithelia. Furthermore, the initially differentiated hair cells fail to form stereociliary bundles and degenerate by apoptosis in the Brn-3c−/− mice. These data indicate a crucial role for Brn-3c in maturation, survival and migration of hair cells, but not in proliferation or commitment of hair cell progenitors.

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