scholarly journals Ganglioside GM3 is essential for the structural integrity and function of cochlear hair cells

2015 ◽  
Vol 24 (10) ◽  
pp. 2796-2807 ◽  
Author(s):  
M. Yoshikawa ◽  
S. Go ◽  
S.-i. Suzuki ◽  
A. Suzuki ◽  
Y. Katori ◽  
...  
Keyword(s):  
Hair Cells ◽  
Structural Integrity ◽  
Ganglioside Gm3 ◽  
Cochlear Hair Cells ◽  
And Function

Shaker-1 mutations reveal roles for myosin VIIA in both development and function of cochlear hair cells

Development ◽  
1998 ◽  
Vol 125 (4) ◽  
pp. 557-566 ◽  
Author(s):  
T. Self ◽  
M. Mahony ◽  
J. Fleming ◽  
J. Walsh ◽  
S.D. Brown ◽  
...  
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Usher Syndrome ◽  
Orthologous Gene ◽  
Cell Development ◽  
Cochlear Hair Cells ◽  
Cochlear Hair Cell ◽  
Show Evidence ◽  
Myosin Viia ◽  
And Function

The mouse shaker-1 locus, Myo7a, encodes myosin VIIA and mutations in the orthologous gene in humans cause Usher syndrome type 1B or non-syndromic deafness. Myo7a is expressed very early in sensory hair cell development in the inner ear. We describe the effects of three mutations on cochlear hair cell development and function. In the Myo7a816SB and Myo7a6J mutants, stereocilia grow and form rows of graded heights as normal, but the bundles become progressively more disorganised. Most of these mutants show no gross electrophysiological responses, but some did show evidence of hair cell depolarisation despite the disorganisation of their bundles. In contrast, the original shaker-1 mutants, Myo7ash1, had normal early development of stereocilia bundles, but still showed abnormal cochlear responses. These findings suggest that myosin VIIA is required for normal stereocilia bundle organisation and has a role in the function of cochlear hair cells.

Nicotinic acetylcholine receptor redux: Discovery of accessories opens therapeutic vistas

Science ◽  
2021 ◽  
Vol 373 (6556) ◽  
pp. eabg6539
Author(s):  
Jose A. Matta ◽  
Shenyan Gu ◽  
Weston B. Davini ◽  
David S. Bredt
Keyword(s):  
Hair Cells ◽  
Sensory Transduction ◽  
Spinal Ganglia ◽  
High Confidence ◽  
Cochlear Hair Cells ◽  
Central Neurons ◽  
Physiological Processes ◽  
Tobacco Addiction ◽  
And Function ◽  
Auditory Disorders

The neurotransmitter acetylcholine (ACh) acts in part through a family of nicotinic ACh receptors (nAChRs), which mediate diverse physiological processes including muscle contraction, neurotransmission, and sensory transduction. Pharmacologically, nAChRs are responsible for tobacco addiction and are targeted by medicines for hypertension and dementia. Nicotinic AChRs were the first ion channels to be isolated. Recent studies have identified molecules that control nAChR biogenesis, trafficking, and function. These nAChR accessories include protein and chemical chaperones as well as auxiliary subunits. Whereas some factors act on many nAChRs, others are receptor specific. Discovery of these regulatory mechanisms is transforming nAChR research in cells and tissues ranging from central neurons to spinal ganglia to cochlear hair cells. Nicotinic AChR–specific accessories also enable drug discovery on high-confidence targets for psychiatric, neurological, and auditory disorders.

scholarly journals The Kinocilia of Cochlear Hair Cells: Structures, Functions, and Diseases

2021 ◽  
Vol 9 ◽  
Author(s):  
Difei Wang ◽  
Jun Zhou
Keyword(s):  
Auditory System ◽  
Hair Cells ◽  
Primary Cilia ◽  
Structure And Function ◽  
Biochemical Reactions ◽  
Cochlear Hair Cells ◽  
Evolutionarily Conserved ◽  
Genes Encoding ◽  
And Function ◽  
The Brain

Primary cilia are evolutionarily conserved and highly specialized organelles that protrude from cell membranes. Mutations in genes encoding ciliary proteins can cause structural and functional ciliary defects and consequently multiple diseases, collectively termed ciliopathies. The mammalian auditory system is responsible for perceiving external sound stimuli that are ultimately processed in the brain through a series of physical and biochemical reactions. Here we review the structure and function of the specialized primary cilia of hair cells, termed kinocilia, found in the mammalian auditory system. We also discuss areas that might prove amenable for therapeutic management of auditory ciliopathies.

scholarly journals Attenuating Cardiac Pulsations within the Cochlea: Structure and Function of Tortuous Vessels Feeding Stria Vascularis

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mattia Carraro ◽  
Jaina Negandhi ◽  
Jafri Kuthubutheen ◽  
Evan J. Propst ◽  
Lukas Kus ◽  
...  
Keyword(s):  
Hair Cells ◽  
Stria Vascularis ◽  
Vascular Anatomy ◽  
Biological Noise ◽  
Pulsatile Blood Flow ◽  
Cochlear Hair Cells ◽  
Cardiac Pulse ◽  
And Function ◽  
Pressure Changes

The mammalian ear has an extraordinary capacity to detect very low-level acoustic signals from the environment. Sound pressures as low as a few μPa (−10 dB SPL) can activate cochlear hair cells. To achieve this sensitivity, biological noise has to be minimized including that generated by cardiovascular pulsation. Generally, cardiac pressure changes are transmitted to most peripheral capillary beds; however, such signals within the stria vascularis of the cochlea would be highly disruptive. Not least, it would result in a constant auditory sensation of heartbeat. We investigate special adaptations in cochlear vasculature that serve to attenuate cardiac pulse signals. We describe the structure of tortuous arterioles that feed stria vascularis as seen in corrosion casts of the cochlea. We provide a mathematical model to explain the role of this unique vascular anatomy in dampening pulsatile blood flow to the stria vascularis.

Fluorocitrate Neural Dystrophy of the Guinea Pig Cochlea

1975 ◽  
Vol 33 ◽  
pp. 368-369
Author(s):  
G.J. Spector ◽  
C.D. Carr ◽  
I. Kaufman Arenberg ◽  
R.H. Maisel
Keyword(s):  
Hearing Loss ◽  
Hair Cells ◽  
Sodium Phosphate ◽  
Sensory Cells ◽  
Barium Salt ◽  
Perfusion Medium ◽  
Cochlear Hair Cells ◽  
Neural Degeneration ◽  
Sodium Phosphate Buffer ◽  
Cochlear Neurons

All studies on primary neural degeneration in the cochlea have evaluated the end stages of degeneration or the indiscriminate destruction of both sensory cells and cochlear neurons. We have developed a model which selectively simulates the dystrophic changes denoting cochlear neural degeneration while sparing the cochlear hair cells. Such a model can be used to define more precisely the mechanism of presbycusis or the hearing loss in aging man.Twenty-two pigmented guinea pigs (200-250 gm) were perfused by the perilymphatic route as live preparations using fluorocitrate in various concentrations (15-250 ug/cc) and at different incubation times (5-150 minutes). The barium salt of DL fluorocitrate, (C6H4O7F)2Ba3, was reacted with 1.0N sulfuric acid to precipitate the barium as a sulfate. The perfusion medium was prepared, just prior to use, as follows: sodium phosphate buffer 0.2M, pH 7.4 = 9cc; fluorocitrate = 15-200 mg/cc; and sucrose = 0.2M.

Pengaruh sisplatin dosis tinggi terhadap penurunan fungsi sel rambut luar koklea

2013 ◽  
Vol 40 (2) ◽  
Author(s):  
Asti Kristianti ◽  
Teti Madiadipoera ◽  
Bogi Soeseno
Keyword(s):  
Hair Cells ◽  
Malignant Neoplasm ◽  
Otoacoustic Emission ◽  
Outer Hair Cells ◽  
High Dose ◽  
Distortion Product Otoacoustic Emission ◽  
Inclusion Criteria ◽  
Cochlear Hair Cells ◽  
Distortion Product ◽  
Bilateral Sensorineural Hearing Loss

Background: Chemotherapy is worldwide used nowadays, and its toxicity still remain a problemespecially toxicity to the ear (ototoxicity). Cisplatin (cis-diamminedichloroplatinum) is one of themost commonly used chemotherapy and highly potent in treating epithelial malignancies. Ototoxicitycaused by cisplatin is irreversible, progressive, bilateral, sensorineural hearing loss especially on highfrequency (4-8 KHz) accompanied by tinnitus. Purpose: To observe the cochlear outer hair cells damagein malignancies patients treated with cisplatin. Methods: This study is an observational analytic studywith prospective design to determine the influence of high dose cisplatin on cochlear outer hair cellsfunction. The research was carried out at the ENT-HNS Department, Hasan Sadikin General HospitalBandung, from November 2007 until June 2008. Audiometry, tympanometry, and distortion productotoacoustic emission (DPOAE) examinations were conducted before chemotherapy and DPOAE, andtimpanometry was again measured three days after first and second cycles of cisplatin administration. McNemar test was performed to calculate the effects of high-dose cisplatin to the cochlear outer haircells function. To compare pre and post-cisplatin on alteration of cochlear hair cells function, Wilcoxontest was used. Results: In this study 60 ears from 30 subjects that meet the inclusion criteria, consistedof 25 man (83.3%) and 5 women (16.7%). The prevalence of damaged cochlear outer hair cells were63% at first cycle and 70% at second cycle of cisplatin administration. The decline of cochlear outerhair cells function was significant (p<0.001). Conclusion: High-dose cisplatin decreases cochlear outerhair cells function in patients with malignant neoplasm. Abstrak : Latar belakang: Kemoterapi sekarang rutin digunakan secara klinis di seluruh dunia. Sejalan denganhal tersebut toksisitas kemoterapi, khususnya terhadap telinga saat ini menjadi perhatian. Sisplatin(cis-diamminedichloroplatinum) adalah salah satu obat kemoterapi yang paling banyak digunakandan paling manjur untuk terapi keganasan epitelial. Efek ototoksik sisplatin yaitu terjadi gangguandengar sensorineural yang irreversible, progresif, bilateral pada frekuensi tinggi (4-8 kHz), dan disertaidengan tinitus. Tujuan: Untuk menilai penurunan fungsi sel rambut luar koklea pada penderita tumorganas sesudah pemberian sisplatin dosis tinggi dengan menggunakan DPOAE. Metode: Studi analitikobservasional dengan rancangan prospektif di Bagian IK. THT-KL RS. Hasan Sadikin Bandung mulaibulan November 2007 sampai dengan Juni 2008. Pada penelitian ini dilakukan pemeriksaan audiometrinada murni, timpanometri, dan distortion product otoacoustic emission (DPOAE) prakemoterapi, kemudianDPOAE dan timpanometri diulang tiga hari sesudah siklus pertama dan kedua kemoterapi sisplatin. Datayang diperoleh diuji dengan uji McNemar dan uji Wilcoxon. Hasil: Dari penelitian didapat 60 telingadari 30 subjek penelitian yang memenuhi kriteria inklusi yang terdiri dari 25 laki-laki (83,3%) dan 5perempuan (16,7%). Insidens penurunan fungsi sel rambut luar koklea sebesar 63% (38 kasus) sesudahsiklus pertama dan 70% (42 kasus) sesudah siklus kedua. Hubungan penurunan fungsi sel rambut luarkoklea memberikan nilai yang sangat bermakna sejak pemberian siklus pertama (p<0,001). Kesimpulan:Pemberian sisplatin dosis tinggi pada penderita tumor ganas menyebabkan penurunan fungsi sel rambutluar koklea.Kata kunci: kemoterapi, sisplatin dosis tinggi, sel rambut luar koklea.

scholarly journals A two-photon FRAP protocol to measure the stereociliary membrane diffusivity in rat cochlear hair cells

2021 ◽  
Vol 2 (3) ◽  
pp. 100637
Author(s):  
Shefin S. George ◽  
Charles R. Steele ◽  
Anthony J. Ricci
Keyword(s):  
Hair Cells ◽  
Cochlear Hair Cells ◽  
Two Photon

scholarly journals Development in the Mammalian Auditory System Depends on Transcription Factors

2021 ◽  
Vol 22 (8) ◽  
pp. 4189
Author(s):  
Karen L. Elliott ◽  
Gabriela Pavlínková ◽  
Victor V. Chizhikov ◽  
Ebenezer N. Yamoah ◽  
Bernd Fritzsch
Keyword(s):  
Transcription Factors ◽  
Cell Fate ◽  
Auditory System ◽  
Hair Cells ◽  
System Development ◽  
Neuronal Cell ◽  
Spiral Ganglion Neuron ◽  
Cochlear Hair Cells ◽  
Cochlear Nuclei ◽  
Bhlh Genes

We review the molecular basis of several transcription factors (Eya1, Sox2), including the three related genes coding basic helix–loop–helix (bHLH; see abbreviations) proteins (Neurog1, Neurod1, Atoh1) during the development of spiral ganglia, cochlear nuclei, and cochlear hair cells. Neuronal development requires Neurog1, followed by its downstream target Neurod1, to cross-regulate Atoh1 expression. In contrast, hair cells and cochlear nuclei critically depend on Atoh1 and require Neurod1 expression for interactions with Atoh1. Upregulation of Atoh1 following Neurod1 loss changes some vestibular neurons’ fate into “hair cells”, highlighting the significant interplay between the bHLH genes. Further work showed that replacing Atoh1 by Neurog1 rescues some hair cells from complete absence observed in Atoh1 null mutants, suggesting that bHLH genes can partially replace one another. The inhibition of Atoh1 by Neurod1 is essential for proper neuronal cell fate, and in the absence of Neurod1, Atoh1 is upregulated, resulting in the formation of “intraganglionic” HCs. Additional genes, such as Eya1/Six1, Sox2, Pax2, Gata3, Fgfr2b, Foxg1, and Lmx1a/b, play a role in the auditory system. Finally, both Lmx1a and Lmx1b genes are essential for the cochlear organ of Corti, spiral ganglion neuron, and cochlear nuclei formation. We integrate the mammalian auditory system development to provide comprehensive insights beyond the limited perception driven by singular investigations of cochlear neurons, cochlear hair cells, and cochlear nuclei. A detailed analysis of gene expression is needed to understand better how upstream regulators facilitate gene interactions and mammalian auditory system development.

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