scholarly journals Outcomes of Peptide Vaccine GV1001 Treatment in a Murine Model of Acute Noise-Induced Hearing Loss

Antioxidants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 112
Author(s):  
Sang-Yeon Lee ◽  
Jae Joon Han ◽  
Sang-Youp Lee ◽  
Gaon Jung ◽  
Hyun Jin Min ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hearing Loss ◽  
White Noise ◽  
Hair Cells ◽  
Murine Model ◽  
Outer Hair Cells ◽  
Saline Control ◽  
Noise Induced Hearing Loss ◽  
Cochlear Hair Cells ◽  
Ribbon Synapses

Noise-induced hearing loss (NIHL) is primarily caused by damage to cochlear hair cells, associated with synaptopathy. The novel cell-penetrating peptide GV1001, an antitumor agent, also has antioxidant and anti-inflammatory effects, and is otoprotective in a murine model of kanamycin-induced ototoxicity. Here, we explored whether GV1001 attenuated NIHL, and the underlying mechanism at play. We established an NIHL model by exposing 4- to 6-week-old C57/BL6 mice to white noise at 120 dB SPL for 2 h, resulting in a significant permanent threshold shift (PTS). We then subcutaneously injected saline (control), GV1001, or dexamethasone immediately after cessation of PTS-noise exposure and evaluated the threshold shifts, structural damages to outer hair cells (OHCs), and ribbon synapses. We also verified whether GV1001 attenuates oxidative stress at the level of lipid peroxidation or protein nitration in OHCs 1 h after exposure to white noise at 120 dB SPL. GV1001-treated mice exhibited significantly less hearing threshold shifts over 2 weeks and preserved OHCs and ribbon synapses compared with controls. Similarly, dexamethasone-treated mice showed comparable protection against NIHL. Importantly, GV1001 markedly attenuated oxidative stress in OHCs. Our findings suggest that GV1001 may protect against NIHL by lowering oxidative stress and may serve as preventive or adjuvant treatment.

scholarly journals Primed to die: an investigation of the genetic mechanisms underlying noise-induced hearing loss and cochlear damage in homozygous Foxo3-knockout mice

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Holly J. Beaulac ◽  
Felicia Gilels ◽  
Jingyuan Zhang ◽  
Sarah Jeoung ◽  
Patricia M. White
Keyword(s):  
Oxidative Stress ◽  
Hearing Loss ◽  
Noise Exposure ◽  
Multiphoton Microscopy ◽  
Cell Loss ◽  
Outer Hair Cells ◽  
Noise Induced Hearing Loss ◽  
Knock Out ◽  
Cell Death Pathway ◽  
Cochlear Damage

AbstractThe prevalence of noise-induced hearing loss (NIHL) continues to increase, with limited therapies available for individuals with cochlear damage. We have previously established that the transcription factor FOXO3 is necessary to preserve outer hair cells (OHCs) and hearing thresholds up to two weeks following mild noise exposure in mice. The mechanisms by which FOXO3 preserves cochlear cells and function are unknown. In this study, we analyzed the immediate effects of mild noise exposure on wild-type, Foxo3 heterozygous (Foxo3+/−), and Foxo3 knock-out (Foxo3−/−) mice to better understand FOXO3’s role(s) in the mammalian cochlea. We used confocal and multiphoton microscopy to examine well-characterized components of noise-induced damage including calcium regulators, oxidative stress, necrosis, and caspase-dependent and caspase-independent apoptosis. Lower immunoreactivity of the calcium buffer Oncomodulin in Foxo3−/− OHCs correlated with cell loss beginning 4 h post-noise exposure. Using immunohistochemistry, we identified parthanatos as the cell death pathway for OHCs. Oxidative stress response pathways were not significantly altered in FOXO3’s absence. We used RNA sequencing to identify and RT-qPCR to confirm differentially expressed genes. We further investigated a gene downregulated in the unexposed Foxo3−/− mice that may contribute to OHC noise susceptibility. Glycerophosphodiester phosphodiesterase domain containing 3 (GDPD3), a possible endogenous source of lysophosphatidic acid (LPA), has not previously been described in the cochlea. As LPA reduces OHC loss after severe noise exposure, we treated noise-exposed Foxo3−/− mice with exogenous LPA. LPA treatment delayed immediate damage to OHCs but was insufficient to ultimately prevent their death or prevent hearing loss. These results suggest that FOXO3 acts prior to acoustic insult to maintain cochlear resilience, possibly through sustaining endogenous LPA levels.

Outer hair cells in the mammalian cochlea and noise-induced hearing loss

Nature ◽  
1985 ◽  
Vol 315 (6021) ◽  
pp. 662-665 ◽  
Author(s):  
A. R. Cody ◽  
I. J. Russell
Keyword(s):  
Hearing Loss ◽  
Hair Cells ◽  
Outer Hair Cells ◽  
Noise Induced Hearing Loss

scholarly journals Disruption of Hars2 in Cochlear Hair Cells Causes Progressive Mitochondrial Dysfunction and Hearing Loss in Mice

2021 ◽  
Vol 15 ◽  
Author(s):  
Pengcheng Xu ◽  
Longhao Wang ◽  
Hu Peng ◽  
Huihui Liu ◽  
Hongchao Liu ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Mitochondrial Dysfunction ◽  
Hair Cells ◽  
Cell Loss ◽  
Outer Hair Cells ◽  
Hair Cell Loss ◽  
Progressive Hearing Loss ◽  
Cochlear Hair Cells ◽  
Inner Hair Cells

Mutations in a number of genes encoding mitochondrial aminoacyl-tRNA synthetases lead to non-syndromic and/or syndromic sensorineural hearing loss in humans, while their cellular and physiological pathology in cochlea has rarely been investigated in vivo. In this study, we showed that histidyl-tRNA synthetase HARS2, whose deficiency is associated with Perrault syndrome 2 (PRLTS2), is robustly expressed in postnatal mouse cochlea including the outer and inner hair cells. Targeted knockout of Hars2 in mouse hair cells resulted in delayed onset (P30), rapidly progressive hearing loss similar to the PRLTS2 hearing phenotype. Significant hair cell loss was observed starting from P45 following elevated reactive oxygen species (ROS) level and activated mitochondrial apoptotic pathway. Despite of normal ribbon synapse formation, whole-cell patch clamp of the inner hair cells revealed reduced calcium influx and compromised sustained synaptic exocytosis prior to the hair cell loss at P30, consistent with the decreased supra-threshold wave I amplitudes of the auditory brainstem response. Starting from P14, increasing proportion of morphologically abnormal mitochondria was observed by transmission electron microscope, exhibiting swelling, deformation, loss of cristae and emergence of large intrinsic vacuoles that are associated with mitochondrial dysfunction. Though the mitochondrial abnormalities are more prominent in inner hair cells, it is the outer hair cells suffering more severe cell loss. Taken together, our results suggest that conditional knockout of Hars2 in mouse cochlear hair cells leads to accumulating mitochondrial dysfunction and ROS stress, triggers progressive hearing loss highlighted by hair cell synaptopathy and apoptosis, and is differentially perceived by inner and outer hair cells.

scholarly journals Treatment With Calcineurin Inhibitor FK506 Attenuates Noise-Induced Hearing Loss

2021 ◽  
Vol 9 ◽  
Author(s):  
Zu-Hong He ◽  
Song Pan ◽  
Hong-Wei Zheng ◽  
Qiao-Jun Fang ◽  
Kayla Hill ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hair Cells ◽  
Calcineurin Inhibitor ◽  
Noise Exposure ◽  
Cell Loss ◽  
Outer Hair Cells ◽  
Oxygen Species ◽  
Noise Induced Hearing Loss ◽  
Activated T Cells ◽  
Interfering Rna

Attenuation of noise-induced hair cell loss and noise-induced hearing loss (NIHL) by treatment with FK506 (tacrolimus), a calcineurin (CaN/PP2B) inhibitor used clinically as an immunosuppressant, has been previously reported, but the downstream mechanisms of FK506-attenuated NIHL remain unknown. Here we showed that CaN immunolabeling in outer hair cells (OHCs) and nuclear factor of activated T-cells isoform c4 (NFATc4/NFAT3) in OHC nuclei are significantly increased after moderate noise exposure in adult CBA/J mice. Consequently, treatment with FK506 significantly reduces moderate-noise-induced loss of OHCs and NIHL. Furthermore, induction of reactive oxygen species (ROS) by moderate noise was significantly diminished by treatment with FK506. In agreement with our previous finding that autophagy marker microtubule-associated protein light chain 3B (LC3B) does not change in OHCs under conditions of moderate-noise-induced permanent threshold shifts, treatment with FK506 increases LC3B immunolabeling in OHCs after exposure to moderate noise. Additionally, prevention of NIHL by treatment with FK506 was partially abolished by pretreatment with LC3B small interfering RNA. Taken together, these results indicate that attenuation of moderate-noise-induced OHC loss and hearing loss by FK506 treatment occurs not only via inhibition of CaN activity but also through inhibition of ROS and activation of autophagy.

scholarly journals Umbilical Cord Mesenchymal Stromal Cell-Derived Exosomes Rescue the Loss of Outer Hair Cells and Repair Cochlear Damage in Cisplatin-Injected Mice

2021 ◽  
Vol 22 (13) ◽  
pp. 6664
Author(s):  
Stella Chin-Shaw Tsai ◽  
Kuender D. Yang ◽  
Kuang-Hsi Chang ◽  
Frank Cheau-Feng Lin ◽  
Ruey-Hwang Chou ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Umbilical Cord ◽  
Hair Cells ◽  
Round Window ◽  
Outer Hair Cells ◽  
Protective Effects ◽  
Cochlear Hair Cells ◽  
Potential Applications ◽  
Round Window Niche

Umbilical cord-derived mesenchymal stromal cells (UCMSCs) have potential applications in regenerative medicine. UCMSCs have been demonstrated to repair tissue damage in many inflammatory and degenerative diseases. We have previously shown that UCMSC exosomes reduce nerve injury-induced pain in rats. In this study, we characterized UCMSC exosomes using RNA sequencing and proteomic analyses and investigated their protective effects on cisplatin-induced hearing loss in mice. Two independent experiments were designed to investigate the protective effects on cisplatin-induced hearing loss in mice: (i) chronic intraperitoneal cisplatin administration (4 mg/kg) once per day for 5 consecutive days and intraperitoneal UCMSC exosome (1.2 μg/μL) injection at the same time point; and (ii) UCMSC exosome (1.2 μg/μL) injection through a round window niche 3 days after chronic cisplatin administration. Our data suggest that UCMSC exosomes exert protective effects in vivo. The post-traumatic administration of UCMSC exosomes significantly improved hearing loss and rescued the loss of cochlear hair cells in mice receiving chronic cisplatin injection. Neuropathological gene panel analyses further revealed the UCMSC exosomes treatment led to beneficial changes in the expression levels of many genes in the cochlear tissues of cisplatin-injected mice. In conclusion, UCMSC exosomes exerted protective effects in treating ototoxicity-induced hearing loss by promoting tissue remodeling and repair.

scholarly journals Elmod3 knockout leads to progressive hearing loss and abnormalities in cochlear hair cell stereocilia

2019 ◽  
Vol 28 (24) ◽  
pp. 4103-4112 ◽  
Author(s):  
Wu Li ◽  
Yong Feng ◽  
Anhai Chen ◽  
Taoxi Li ◽  
Sida Huang ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Actin Cytoskeleton ◽  
Hearing Impairment ◽  
Hair Cells ◽  
Organ Of Corti ◽  
Vestibular Function ◽  
Outer Hair Cells ◽  
Auditory Function ◽  
Cochlear Hair Cells

Abstract ELMOD3, an ARL2 GTPase-activating protein, is implicated in causing hearing impairment in humans. However, the specific role of ELMOD3 in auditory function is still far from being elucidated. In the present study, we used the CRISPR/Cas9 technology to establish an Elmod3 knockout mice line in the C57BL/6 background (hereinafter referred to as Elmod3−/− mice) and investigated the role of Elmod3 in the cochlea and auditory function. Elmod3−/− mice started to exhibit hearing loss from 2 months of age, and the deafness progressed with aging, while the vestibular function of Elmod3−/− mice was normal. We also observed that Elmod3−/− mice showed thinning and receding hair cells in the organ of Corti and much lower expression of F-actin cytoskeleton in the cochlea compared with wild-type mice. The deafness associated with the mutation may be caused by cochlear hair cells dysfunction, which manifests with shortening and fusion of inner hair cells stereocilia and progressive degeneration of outer hair cells stereocilia. Our finding associates Elmod3 deficiencies with stereocilia dysmorphologies and reveals that they might play roles in the actin cytoskeleton dynamics in cochlear hair cells, and thus relate to hearing impairment.

scholarly journals Specific Influences of Early Acoustic Environments on Cochlear Hair Cells in Postnatal Mice

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Aoshuang Chang ◽  
Peng Chen ◽  
Shasha Guo ◽  
Nana Xu ◽  
Wenlu Pan ◽  
...  
Keyword(s):  
Hair Cells ◽  
Acoustic Stimulation ◽  
Outer Hair Cells ◽  
Mature Stage ◽  
Cochlear Hair Cells ◽  
Acoustic Environment ◽  
Postnatal Maturation ◽  
Ribbon Synapses ◽  
Brainstem Response ◽  
Acoustic Environments

The auditory function develops and matures after birth in many mammalian species. After hearing onset, environmental sounds exert profound and long-term effects on auditory functions. However, the effects of the acoustic environment on the functional development of the peripheral auditory system, especially the cochlear sensory hair cells, are still unclear. In the present study, we exposed mouse pups to frequency-enriched acoustic environments in postnatal days 0–14. The results indicated that the acoustic environment significantly decreased the threshold of the auditory brainstem response in a frequency-specific manner. Compared with controls, no difference was found in the number and alignment of inner and outer hair cells or in the length of hair bundles after acoustic overstimulation. The expression and function of prestin, the motor protein of outer hair cells (OHCs), were specifically increased in OHCs activated by acoustic stimulation at postnatal days 7–11. We analyzed the postnatal maturation of ribbon synapses in the hair cell areas. After acoustic stimulation, the number of ribbon synapses was closer to the mature stage than to the controls. Taken together, these data indicate that early acoustic exposure could promote the functional maturation of cochlear hair cells and the development of hearing.

scholarly journals Impulse Noise Induced Hidden Hearing Loss, Hair Cell Ciliary Changes and Oxidative Stress in Mice

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1880
Author(s):  
Paul Gratias ◽  
Jamal Nasr ◽  
Corentin Affortit ◽  
Jean-Charles Ceccato ◽  
Florence François ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hearing Loss ◽  
Hair Cells ◽  
Impulse Noise ◽  
Noise Exposure ◽  
Morphological Changes ◽  
Nerve Fibers ◽  
Outer Hair Cells ◽  
Hidden Hearing Loss ◽  
The Impact

Recent studies demonstrated that reversible continuous noise exposure may induce a temporary threshold shift (TTS) with a permanent degeneration of auditory nerve fibers, although hair cells remain intact. To probe the impact of TTS-inducing impulse noise exposure on hearing, CBA/J Mice were exposed to noise impulses with peak pressures of 145 dB SPL. We found that 30 min after exposure, the noise caused a mean elevation of ABR thresholds of ~30 dB and a reduction in DPOAE amplitude. Four weeks later, ABR thresholds and DPOAE amplitude were back to normal in the higher frequency region (8–32 kHz). At lower frequencies, a small degree of PTS remained. Morphological evaluations revealed a disturbance of the stereociliary bundle of outer hair cells, mainly located in the apical regions. On the other hand, the reduced suprathreshold ABR amplitudes remained until 4 weeks later. A loss of synapse numbers was observed 24 h after exposure, with full recovery two weeks later. Transmission electron microscopy revealed morphological changes at the ribbon synapses by two weeks post exposure. In addition, increased levels of oxidative stress were observed immediately after exposure, and maintained for a further 2 weeks. These results clarify the pathology underlying impulse noise-induced sensory dysfunction, and suggest possible links between impulse-noise injury, cochlear cell morphology, metabolic changes, and hidden hearing loss.

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