scholarly journals N-acetyl-cysteine prevents age-related hearing loss and the progressive loss of inner hair cells in γ-glutamyl transferase 1 deficient mice

Aging ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 730-750 ◽  
Author(s):  
Dalian Ding ◽  
Haiyan Jiang ◽  
Guang-Di Chen ◽  
Chantal Longo-Guess ◽  
Vijaya Prakash Krishnan Muthaiah ◽  
...  
F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 927 ◽  
Author(s):  
M Charles Liberman

The classic view of sensorineural hearing loss has been that the primary damage targets are hair cells and that auditory nerve loss is typically secondary to hair cell degeneration. Recent work has challenged that view. In noise-induced hearing loss, exposures causing only reversible threshold shifts (and no hair cell loss) nevertheless cause permanent loss of >50% of the synaptic connections between hair cells and the auditory nerve. Similarly, in age-related hearing loss, degeneration of cochlear synapses precedes both hair cell loss and threshold elevation. This primary neural degeneration has remained a “hidden hearing loss” for two reasons: 1) the neuronal cell bodies survive for years despite loss of synaptic connection with hair cells, and 2) the degeneration is selective for auditory nerve fibers with high thresholds. Although not required for threshold detection when quiet, these high-threshold fibers are critical for hearing in noisy environments. Research suggests that primary neural degeneration is an important contributor to the perceptual handicap in sensorineural hearing loss, and it may be key to the generation of tinnitus and other associated perceptual anomalies. In cases where the hair cells survive, neurotrophin therapies can elicit neurite outgrowth from surviving auditory neurons and re-establishment of their peripheral synapses; thus, treatments may be on the horizon.


Author(s):  
Prathamesh Thangaraj Nadar Ponniah ◽  
Shahar Taiber ◽  
Michal Caspi ◽  
Tal Koffler-Brill ◽  
Amiel A. Dror ◽  
...  

AbstractStriatin, a subunit of the serine/threonine phosphatase PP2A, is a core member of the conserved striatin-interacting phosphatase and kinase (STRIPAK) complexes. The protein is expressed in the cell junctions between epithelial cells, which play a role in maintaining cell-cell junctional integrity. Since adhesion is crucial for the function of the mammalian inner ear, we examined the localization and function of striatin in the mouse cochlea. Our results show that in neonatal mice, striatin is specifically expressed in the cell-cell junctions of the inner hair cells, the receptor cells in the mammalian cochlea. Auditory brainstem response measurements of striatin-deficient mice indicated a progressive, high-frequency hearing loss, suggesting that striatin is essential for normal hearing. Moreover, scanning electron micrographs of the organ of Corti revealed a moderate degeneration of the outer hair cells in the middle and basal regions, concordant with the high-frequency hearing loss. Importantly, striatin-deficient mice show aberrant ribbon synapse maturation that may lead to the observed auditory impairment. Together, these results suggest a novel function for striatin in the mammalian auditory system.


2006 ◽  
Vol 27 (4) ◽  
pp. 228-236 ◽  
Author(s):  
John Mills ◽  
Richard Schmiedt ◽  
Bradley Schulte ◽  
Judy Dubno

2020 ◽  
Vol 117 (21) ◽  
pp. 11811-11819 ◽  
Author(s):  
Luis E. Boero ◽  
Valeria C. Castagna ◽  
Gonzalo Terreros ◽  
Marcelo J. Moglie ◽  
Sebastián Silva ◽  
...  

“Growing old” is the most common cause of hearing loss. Age-related hearing loss (ARHL) (presbycusis) first affects the ability to understand speech in background noise, even when auditory thresholds in quiet are normal. It has been suggested that cochlear denervation (“synaptopathy”) is an early contributor to age-related auditory decline. In the present work, we characterized age-related cochlear synaptic degeneration and hair cell loss in mice with enhanced α9α10 cholinergic nicotinic receptors gating kinetics (“gain of function” nAChRs). These mediate inhibitory olivocochlear feedback through the activation of associated calcium-gated potassium channels. Cochlear function was assessed via distortion product otoacoustic emissions and auditory brainstem responses. Cochlear structure was characterized in immunolabeled organ of Corti whole mounts using confocal microscopy to quantify hair cells, auditory neurons, presynaptic ribbons, and postsynaptic glutamate receptors. Aged wild-type mice had elevated acoustic thresholds and synaptic loss. Afferent synapses were lost from inner hair cells throughout the aged cochlea, together with some loss of outer hair cells. In contrast, cochlear structure and function were preserved in aged mice with gain-of-function nAChRs that provide enhanced olivocochlear inhibition, suggesting that efferent feedback is important for long-term maintenance of inner ear function. Our work provides evidence that olivocochlear-mediated resistance to presbycusis-ARHL occurs via the α9α10 nAChR complexes on outer hair cells. Thus, enhancement of the medial olivocochlear system could be a viable strategy to prevent age-related hearing loss.


2005 ◽  
Vol 25 (2) ◽  
pp. 847-853 ◽  
Author(s):  
Benjamin Delprat ◽  
Jérôme Ruel ◽  
Matthieu J. Guitton ◽  
Ghyslaine Hamard ◽  
Marc Lenoir ◽  
...  

ABSTRACT In the cochlea, the mammalian auditory organ, fibrocytes of the mesenchymal nonsensory regions play important roles in cochlear physiology, including the maintenance of ionic and hydric components in the endolymph. Occurrence of human deafness in fibrocyte alterations underlines their critical roles in auditory function. We recently described a novel gene, Otos, which encodes otospiralin, a small protein of unknown function that is produced by the fibrocytes of the cochlea and vestibule. We now have generated mice with deletion of Otos and found that they show moderate deafness, with no frequency predominance. Histopathology revealed a degeneration of type II and IV fibrocytes, while hair cells and stria vascularis appeared normal. Together, these findings suggest that impairment of fibrocytes caused by the loss in otospiralin leads to abnormal cochlear physiology and auditory function. This moderate dysfunction may predispose to age-related hearing loss.


2018 ◽  
Vol 38 (13) ◽  
pp. 3177-3189 ◽  
Author(s):  
Teerawat Wiwatpanit ◽  
Natalie N. Remis ◽  
Aisha Ahmad ◽  
Yingjie Zhou ◽  
John C. Clancy ◽  
...  

2011 ◽  
Vol 60 (4) ◽  
pp. 355-361 ◽  
Author(s):  
Hitoshi OKUMURA ◽  
Yuki MIYASAKA ◽  
Yuka MORITA ◽  
Tomoyuki NOMURA ◽  
Yukio MISHIMA ◽  
...  

2016 ◽  
Vol 21 (5) ◽  
pp. 326-332 ◽  
Author(s):  
Qiuhong Huang ◽  
Hao Xiong ◽  
Haidi Yang ◽  
Yongkang Ou ◽  
Zhigang Zhang ◽  
...  

Bcl-2, the first gene shown to be involved in apoptosis, is a potent regulator of cell survival and known to have protective effects against a variety of age-related diseases. However, the possible relationship between hearing and Bcl-2 expression in the cochlea or auditory cortex of C57BL/6 mice, a mouse model of age-related hearing loss, is still unknown. Using RT-PCR, immunohistochemistry, and Western blot analysis, our results show that Bcl-2 is strongly expressed in the inner hair cells and spiral ganglion neurons of young mice. In addition, moderate Bcl-2 expression is also detected in the outer hair cells and in the neurons of the auditory cortex. A significant reduction of Bcl-2 expression in the cochlea or auditory cortex is also associated with elevated hearing thresholds and hair cell loss during aging. The expression pattern of Bcl-2 in the peripheral and central auditory systems suggests that Bcl-2 may play an important role in auditory function serving as a protective molecule against age-related hearing loss.


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