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spiral ganglion neuron

Lijuan Shi, Ying Chang, Xiaowei Li, Steve Aiken, Lijie Liu, Jian Wang
Recent studies on animal models have shown that noise exposure that does not lead to permanent threshold shift (PTS) can cause considerable damage around the synapses between inner hair cells (IHCs) and type-I afferent auditory nerve fibers (ANFs). Disruption of these synapses not only disables the innervated ANFs but also results in the slow degeneration of spiral ganglion neurons if the synapses are not reestablished. Such a loss of ANFs should result in signal coding deficits, which are exacerbated by the bias of the damage toward synapses connecting low-spontaneous-rate (SR) ANFs, which are known to be vital for signal coding in noisy background...
2016: Neural Plasticity
Claudia Frick, Marcus Müller, Ute Wank, Anke Tropitzsch, Benedikt Kramer, Pascal Senn, Helge Rask-Anderson, Karl-Heinz Wiesmüller, Hubert Löwenheim
Cochlear implants (CI) allow for hearing rehabilitation in patients with sensorineural hearing loss or deafness. Restricted CI performance results from the spatial gap between spiral ganglion neurons and the CI, causing current spread that limits spatially restricted stimulation and impairs frequency resolution. This may be substantially improved by guiding peripheral processes of spiral ganglion neurons towards and onto the CI electrode contacts. An injectable, peptide-based hydrogel was developed which may provide a permissive scaffold to facilitate neurite growth towards the CI...
October 4, 2016: Colloids and Surfaces. B, Biointerfaces
Ariane Roemer, Ulrike Köhl, Omid Majdani, Stephan Klöß, Christine Falk, Sabine Haumann, Thomas Lenarz, Andrej Kral, Athanasia Warnecke
BACKGROUND: The success of cochlear implantation may be further improved by minimizing implantation trauma. The physical trauma of implantation and subsequent immunological sequelae can affect residual hearing and the viability of the spiral ganglion. An ideal electrode should therefore decrease post-implantation trauma and provide support to the residual spiral ganglion population. Combining a flexible electrode with cells producing and releasing protective factors could present a potential means to achieve this...
October 7, 2016: Stem Cell Research & Therapy
Sabine Ladrech, Jing Wang, Marc Mathieu, Jean-Luc Puel, Marc Lenoir
High mobility group box 1 (HMGB1) is a DNA-binding protein that facilitates gene transcription and may act extracellularly as a late mediator of inflammation. The roles of HMGB1 in the pathogenesis of the spiral ganglion neurons (SGNs) of the cochlea are currently unknown. In the present study, we tested the hypothesis that early phenotypical changes in the SGNs of the amikacin-poisoned rat cochlea are mediated by HMGB1. Our results showed that a marked downregulation of HMGB1 had occurred by completion of amikacin treatment, coinciding with acute damage at the dendrite extremities of the SGNs...
October 4, 2016: Histochemistry and Cell Biology
Pankhuri Vyas, Jingjing Sherry Wu, Amanda Zimmerman, Paul Fuchs, Elisabeth Glowatzki
Acoustic information propagates from the ear to the brain via spiral ganglion neurons that innervate hair cells in the cochlea. These afferents include unmyelinated type II fibers that constitute 5 % of the total, the majority being myelinated type I neurons. Lack of specific genetic markers of type II afferents in the cochlea has been a roadblock in studying their functional role. Unexpectedly, type II afferents were visualized by reporter proteins induced by tyrosine hydroxylase (TH)-driven Cre recombinase...
September 30, 2016: Journal of the Association for Research in Otolaryngology: JARO
Ruili Xie
Age-related hearing loss (ARHL) is largely attributed to structural changes and functional declines in the peripheral auditory system, which include synaptopathy at the inner hair cell/spiral ganglion cell (SGC) connection as well as the loss of SGCs. However, functional changes at the central terminals of SGCs, namely the auditory nerve synapses in the cochlear nucleus, are not yet fully understood during ARHL. Using young (1-3 months) and old (25-30 months) CBA/CaJ mice, this study evaluated the intrinsic properties of the bushy neurons postsynaptic to the endbulb of Held synapses, and the firing properties of these neurons to direct current injections as well as to synaptic inputs from the auditory nerve...
September 28, 2016: Journal of Neurophysiology
Li Lei, Li Tang
Schwann cells (SCs) have been reported as a possible source of neurotrophic support for spiral ganglion neurons (SGNs). This study was aimed to investigate whether S100A4 was contributed in the functional effects of SCs on SGNs. SCs were transfected with S100A4 vector or small interfering RNA (siRNA) against S100A4, and the transfection efficiency was verified by quantitative PCR (qPCR) and Western blot. The migration of transfected SCs was determined by Transwell assay, and the expression levels of vascular endothelial growth factor precursor (VEGF) and matrix metallopeptidase 9 (MMP-9) were measured by Western blot...
September 26, 2016: Bioengineered
Robert D Frisina, Bo Ding, Xiaoxia Zhu, Joseph P Walton
Age-related hearing loss (ARHL) -presbycusis - is the most prevalent neurodegenerative disease and number one communication disorder of our aged population; and affects hundreds of millions of people worldwide. Its prevalence is close to that of cardiovascular disease and arthritis, and can be a precursor to dementia. The auditory perceptual dysfunction is well understood, but knowledge of the biological bases of ARHL is still somewhat lacking. Surprisingly, there are no FDA-approved drugs for treatment. Based on our previous studies of human subjects, where we discovered relations between serum aldosterone levels and the severity of ARHL, we treated middle age mice with aldosterone, which normally declines with age in all mammals...
September 23, 2016: Aging
B B Xie, H W Li, C F Dai
Objective: To identify the targets of the infrared laser stimulating on the cochlea of guinea pig which evoked auditory brainstem response (oABR), and explore the mechanisms of the infrared neurostimulation. Methods: A polished optical fiber with 200 μm diameter (NA=0.22) was planted into the scala tympani of guinea pigs to stimulate the cochlea of both the normal hearing and acute deafened guinea pigs. The direction of the fiber distal was changed to radiate different regions of the scala tympani, recording the oABR respectively...
September 7, 2016: Zhonghua Er Bi Yan Hou Tou Jing Wai Ke za Zhi, Chinese Journal of Otorhinolaryngology Head and Neck Surgery
Tobias Moser, Christian Vogl
The inner ear uses specialized synapses to indefatigably transmit sound information from hair cells to spiral ganglion neurons at high rates with submillisecond precision. The emerging view is that hair cell synapses achieve their demanding function by employing an unconventional presynaptic molecular composition. Hair cell active zones hold the synaptic ribbon, an electron-dense projection made primarily of RIBEYE, which tethers a halo of synaptic vesicles and is thought to enable a large readily releasable pool of vesicles and to contribute to its rapid replenishment...
2016: F1000Research
Akira Ishiyama, Joni Doherty, Gail Ishiyama, Alicia M Quesnel, Ivan Lopez, Fred H Linthicum
OBJECTIVE: To evaluate for potential causes of delayed loss of residual hearing that variably occurs with hybrid cochlear implants. STUDY DESIGN: Histopathological evaluation of 29 human temporal bone (HTB) with cochlear implant (CI). SETTING: The Neurotology and House HTB Laboratory of UCLA (House-UCLA). SUBJECTS AND METHODS: HTB from CI patients from the House-UCLA HTB Laboratory (n = 28) and one courtesy of Massachusetts Eye and Ear Infirmary (MEEI)...
September 7, 2016: Otology & Neurotology
Hainan Lang, Eishi Nishimoto, Yazhi Xing, LaShardai N Brown, Kenyaria V Noble, Jeremy L Barth, Amanda C LaRue, Kiyoshi Ando, Bradley A Schulte
The peripheral auditory nerve (AN) carries sound information from sensory hair cells to the brain. The present study investigated the contribution of mouse and human hematopoietic stem cells (HSCs) to cellular diversity in the AN following the destruction of neuron cell bodies, also known as spiral ganglion neurons (SGNs). Exposure of the adult mouse cochlea to ouabain selectively killed type I SGNs and disrupted the blood-labyrinth barrier. This procedure also resulted in the upregulation of genes associated with hematopoietic cell homing and differentiation, and provided an environment conducive to the tissue engraftment of circulating stem/progenitor cells into the AN...
October 4, 2016: Molecular Therapy: the Journal of the American Society of Gene Therapy
Yue Fan, Ying Zhang, Rimao Wu, Xingming Chen, Yong Zhang, Xiaowei Chen, Dahai Zhu
To understand the relationship between microRNAs and hearing loss and help clarify the causes of hereditary deafness, we studied the functions of miR-431 in cochleae. We first investigated the spatial-temporal expression profiles of miR-431 in spiral ganglion neurons (SGNs) in cochleae using real-time PCR and miRNA in situ hybridization. These studies showed that expression of miR-431 was high in SGNs in the cochleae of newborn mice, and decreased as development progressed. To test the functional effects of miR-431, we established miR-431 overexpressing transgenic (Tg) mice...
August 18, 2016: Biochimica et Biophysica Acta
Donna S Whitlon
In the United States there are, at present, no drugs that are specifically FDA approved to treat hearing loss. Although several clinical trials are ongoing, including one testing D-methionine that is supported by the US Army, none of these trials directly address the effect of noise exposure on cochlear spiral ganglion neurons. We recently published the first report of a systematic chemical compound screen using primary, mammalian spiral ganglion cultures in which we were able to detect a compound and others in its class that increased neurite elongation, a critical step in restoring cochlear synapses after noise induced hearing loss...
August 2, 2016: Hearing Research
Cynthia L Chow, Parul Trivedi, Madeline P Pyle, Jacob T Matulle, Robert Fettiplace, Samuel P Gubbels
Adult stem cells are undifferentiated cells with the capacity to proliferate and form mature tissue-specific cell types. Nestin is an intermediate filament protein used to identify cells with stem cell characteristics. Its expression has been observed in a population of cells in developing and adult cochleae. In vitro studies using rodent cochlear tissue have documented the potential of nestin-expressing cells to proliferate and form hair and supporting cells. In this study, nestin coupled to green fluorescent protein (GFP) transgenic mice were used to provide a more complete characterization of the spatial and temporal expression of nestin in the inner ear, from organogenesis to adulthood...
October 1, 2016: Stem Cells and Development
Tzu-Lun Ohn, Mark A Rutherford, Zhizi Jing, Sangyong Jung, Carlos J Duque-Afonso, Gerhard Hoch, Maria Magdalena Picher, Anja Scharinger, Nicola Strenzke, Tobias Moser
For sounds of a given frequency, spiral ganglion neurons (SGNs) with different thresholds and dynamic ranges collectively encode the wide range of audible sound pressures. Heterogeneity of synapses between inner hair cells (IHCs) and SGNs is an attractive candidate mechanism for generating complementary neural codes covering the entire dynamic range. Here, we quantified active zone (AZ) properties as a function of AZ position within mouse IHCs by combining patch clamp and imaging of presynaptic Ca(2+) influx and by immunohistochemistry...
August 9, 2016: Proceedings of the National Academy of Sciences of the United States of America
Christian Vogl, Iliana Panou, Gulnara Yamanbaeva, Carolin Wichmann, Sara J Mangosing, Fabio Vilardi, Artur A Indzhykulian, Tina Pangršič, Rosamaria Santarelli, Montserrat Rodriguez-Ballesteros, Thomas Weber, Sangyong Jung, Elena Cardenas, Xudong Wu, Sonja M Wojcik, Kelvin Y Kwan, Ignacio Del Castillo, Blanche Schwappach, Nicola Strenzke, David P Corey, Shuh-Yow Lin, Tobias Moser
The transmembrane recognition complex (TRC40) pathway mediates the insertion of tail-anchored (TA) proteins into membranes. Here, we demonstrate that otoferlin, a TA protein essential for hair cell exocytosis, is inserted into the endoplasmic reticulum (ER) via the TRC40 pathway. We mutated the TRC40 receptor tryptophan-rich basic protein (Wrb) in hair cells of zebrafish and mice and studied the impact of defective TA protein insertion. Wrb disruption reduced otoferlin levels in hair cells and impaired hearing, which could be restored in zebrafish by transgenic Wrb rescue and otoferlin overexpression...
July 25, 2016: EMBO Journal
Michael Perny, Marta Roccio, Denis Grandgirard, Magdalena Solyga, Pascal Senn, Stephen L Leib
UNLABELLED: Hearing loss is an important sequela of pneumococcal meningitis (PM), occurring in up to 30% of survivors. The role of the severity of infection on hearing function and pathomorphological consequences in the cochlea secondary to PM have not been investigated to date. Using a well-established model of PM, we systematically investigated the functional hearing outcome and the long-term fate of neurosensory cells in the cochlea, i.e., hair cells and spiral ganglion neurons (SGNs), with a focus on their tonotopic distribution...
July 20, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Luisa Schäck, Stefan Budde, Thomas Lenarz, Christian Krettek, Gerhard Gross, Henning Windhagen, Andrea Hoffmann, Athanasia Warnecke
AIM OF THE STUDY: The induced expression of the transcription factors neurogenin1 (Neurog1) or neuronal differentiation 1 (NeuroD1) has previously been shown to initiate neuronal differentiation in embryonic stem cells (ESC). Human bone marrow-derived mesenchymal stem cells (hBMSCs) are ethically non-controversial stem cells. However, they are not pluripotent. In cochlear implantation, regeneration or replacement of lost spiral ganglion neurons may be a measure for the improvement of implant function...
October 2016: Tissue & Cell
Takaomi Kurioka, Min Young Lee, Amarins N Heeringa, Lisa A Beyer, Donald L Swiderski, Ariane C Kanicki, Lisa L Kabara, David F Dolan, Susan E Shore, Yehoash Raphael
In experimental animal models of auditory hair cell (HC) loss, insults such as noise or ototoxic drugs often lead to secondary changes or degeneration in non-sensory cells and neural components, including reduced density of spiral ganglion neurons, demyelination of auditory nerve fibers and altered cell numbers and innervation patterns in the cochlear nucleus (CN). However, it is not clear whether loss of HCs alone leads to secondary degeneration in these neural components of the auditory pathway. To elucidate this issue, we investigated changes of central components after cochlear insults specific to HCs using diphtheria toxin receptor (DTR) mice expressing DTR only in HCs and exhibiting complete HC loss when injected with diphtheria toxin (DT)...
September 22, 2016: Neuroscience
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