scholarly journals Cisplatin-Induced Ototoxicity in Rats Is Driven by RIP3-Dependent Necroptosis

Cells ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 409 ◽  
Author(s):  
Mi-Jin Choi ◽  
Hyunsook Kang ◽  
Yun Yeong Lee ◽  
Oak-Sung Choo ◽  
Jeong Hun Jang ◽  
...  
Keyword(s):  
Cell Death ◽  
Spiral Ganglion ◽  
Organ Of Corti ◽  
Auditory Brainstem ◽  
Sprague Dawley ◽  
Western Blots ◽  
Brainstem Response ◽  
Ganglion Neurons

Cisplatin-induced early-onset ototoxicity is linked to hearing loss. The mechanism by which cisplatin causes ototoxicity remains unclear. The purpose of this study was to identify the involvement of receptor-interacting protein kinase (RIP)3-dependent necroptosis in cisplatin-induced ototoxicity in vitro and in vivo. Sprague–Dawley rats (SD, 8 week) were treated via intraperitoneal (i.p.) injection with cisplatin (16 mg/kg for 1 day), and their hearing thresholds were measured by the auditory brainstem response (ABR) method. Hematoxylin and eosin (H & E) staining, immunohistochemistry, and western blots were performed to determine the effect of cisplatin-induced ototoxicity on cochlear morphology. Inhibitor experiments with necrostatin 1 (Nec-1) and Z-VAD were also performed in HEI-OC1 cell line. H&E stains revealed that the necroptotic changes were increased in the organ of Corti (OC) and spiral ganglion neurons (SGNs). Moreover, immunohistochemistry and western blot analysis showed that cisplatin treatment increased the protein levels of RIP3 in both OCs and SGNs. The treatment of Nec-1, a selective RIP1 inhibitor, resulted in markedly suppression of cisplatin-induced cell death in HEI-OC1 cells, whereas Z-VAD treatment did not change the cisplatin-induced cell death. Our results suggest that RIP3-dependent necroptosis was substantial in cisplatin-induced ototoxicity; inner cochlear regions, the OCs, and SGNs were especially sensitive to necroptosis.

scholarly journals Pyroptosis Accelerates Spiral Ganglion Neuronal Degeneration Induced by Aminoglycosides in the Cochlea

2021 ◽  
Author(s):  
Yazhi Xing ◽  
Jia Fang ◽  
Zhuangzhuang Li ◽  
Mingxian Li ◽  
Chengqi Liu ◽  
...  
Keyword(s):  
Cell Death ◽  
Rna Sequencing ◽  
Hair Cells ◽  
Nlrp3 Inflammasome ◽  
Auditory Brainstem Response ◽  
Spiral Ganglion ◽  
Auditory Brainstem ◽  
Response Threshold ◽  
Brainstem Response ◽  
Ganglion Neurons

Abstract Background In aminoglycoside-induced hearing loss, damage to spiral ganglion neurons (SGNs) accelerates gradually after the acute outer hair cell death, accompanied by macrophage infiltration and cytokine release. Pyroptosis plays a critical role in neurodegenerative diseases. Here, we explored the potential role of pyroptosis in SGN degeneration. Methods C57BL/6J mice were randomly divided into a kanamycin plus furosemide group and saline control group. Auditory functions were evaluated by auditory brainstem response tests conducted before treatment and at 1, 5, 15, and 30 days after treatment. HCs and SGNs were assessed for morphological alterations. SGNs were subjected to RNA sequencing and mRNA and protein analyses of NLRP3 inflammasome-related molecules. Macrophage activation was evaluated based on morphological and mRNA alterations. The effect of NLRP3 inhibition on SGN survival after kanamycin treatment was evaluated in organ explant cultures treated with Mcc950, a specific inhibitor of the NLRP3 inflammasome. Results Kanamycin and furosemide administration led to irreversible deterioration of the auditory brainstem response threshold, accompanied by acute loss of outer hair cells and gradually progressive loss of inner hair cells. SGNs showed a progressive decrease in quantity, as well as swelling and membrane rupture, at 15 and 30 days. RNA sequencing of SGNs showed that inflammation and immune-related responses were significantly upregulated, as was the expression of the inflammasome-related gene NLRP3. During 30 days of kanamycin exposure, the canonical pyroptosis pathway was constantly activated in SGNs. Activation and infiltration of microglia-like cells/macrophages, and increased production of cytokines, hallmarks of neuroinflammation, were also observed. Mcc950 significantly ameliorated SGN degeneration by inhibiting NLRP3 expression and promoting release of interleukins 1β and 18. Conclusions Pyroptosis causes cell death during aminoglycoside-induced SGN degeneration. Activation of the NLRP3 inflammasome leads to a cascade of inflammatory events in SGNs. Inhibition of the NLRP3 inflammasome significantly alleviates SGN damage, suggesting that it could serve as a new molecular target for the treatment of aminoglycoside-induced SGN degeneration.

scholarly journals Inner ear pathology and loss of hearing in estrogen receptor-β deficient mice

2009 ◽  
Vol 201 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Rusana Simonoska ◽  
Annika E Stenberg ◽  
Maoli Duan ◽  
Konstantin Yakimchuk ◽  
Anders Fridberger ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Inner Ear ◽  
Spiral Ganglion ◽  
Organ Of Corti ◽  
Auditory Brainstem ◽  
Estrogen Receptor Β ◽  
Knock Out ◽  
Age Related ◽  
Brainstem Response ◽  
Knock Out Mice

There are well known differences between males and females in hearing. In the present study, the role of estrogen receptor-β (ER-β; listed as ESR2 in the MGI Database) in hearing was investigated by comparing hearing and morphology of the inner ear in ER-β knock-out mice (ER-β−/−) with that of wild-type (WT) littermates. Hearing was analyzed with auditory brainstem response audiometry at 3 and 12 months. The ER-β−/− mice were deaf at 1 year of age, and the morphological analysis showed absence of hair cells and loss of the whole organ of Corti initiated in the basal turn of the cochlea. Furthermore, in ER-β−/−, but not in WT mice, the spiral ganglion was lacking many of its neurons. Immunostaining showed the presence of both ER-α (listed as ESR1 in the MGI Database) and ER-β in the nuclei of some neurons in the inner ear in WT mice, but no ER-β was found in the ER-β−/− mice as expected. ER-α staining was predominant in the nuclei of large neurons and ER-β in nuclei of small neurons and fibroblasts. These results reveal that both ERs are present in the inner ear at specific localizations suggesting subtype-specific functions. It is concluded that ER-β is important for the prevention of age-related hearing loss. These findings strengthen the hypothesis that estrogen has a direct effect on hearing functions.

scholarly journals Efficacy of 670 nm Light Therapy to Protect against Photoreceptor Cell Death Is Dependent on the Severity of Damage

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Joshua A. Chu-Tan ◽  
Matt Rutar ◽  
Kartik Saxena ◽  
Yunlu Wu ◽  
Lauren Howitt ◽  
...  
Keyword(s):  
Cell Death ◽  
Photoreceptor Cell ◽  
Light Therapy ◽  
Sprague Dawley ◽  
Respiratory Capacity ◽  
Extracellular Flux ◽  
Sd Rats ◽  
Lower Light

Photobiomodulation at a wavelength of 670 nm has been shown to be effective in preventing photoreceptor cell death in the retina. We treated Sprague-Dawley (SD) rats with varying doses of 670 nm light (9; 18; 36; 90 J/cm2) before exposing them to different intensities of damaging white light (750; 1000; 1500 lux). 670 nm light exhibited a biphasic response in its amelioration of cell death in light-induced degenerationin vivo. Lower light damage intensities required lower doses of 670 nm light to reduce TUNEL cell death. At higher damage intensities, the highest dose of 670 nm light showed protection.In vitro, the Seahorse XFe96 Extracellular Flux Analyzer revealed that 670 nm light directly influences mitochondrial metabolism by increasing the spare respiratory capacity of mitochondria in 661 W photoreceptor-like cells in light damaged conditions. Our findings further support the use of 670 nm light as an effective treatment against retinal degeneration as well as shedding light on the mechanism of protection through the increase of the mitochondrial spare respiratory capacity.

scholarly journals Protection of cochlear synapses from noise-induced excitotoxic trauma by blockade of Ca2+-permeable AMPA receptors

2020 ◽  
Vol 117 (7) ◽  
pp. 3828-3838 ◽  
Author(s):  
Ning Hu ◽  
Mark A. Rutherford ◽  
Steven H. Green
Keyword(s):  
Ampa Receptors ◽  
Spiral Ganglion ◽  
Auditory Brainstem ◽  
Spiral Ganglion Neurons ◽  
Loud Sound ◽  
Selective Blockade ◽  
Hearing Thresholds ◽  
Brainstem Response ◽  
Low Threshold ◽  
Ganglion Neurons

Exposure to loud sound damages the postsynaptic terminals of spiral ganglion neurons (SGNs) on cochlear inner hair cells (IHCs), resulting in loss of synapses, a process termed synaptopathy. Glutamatergic neurotransmission via α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type receptors is required for synaptopathy, and here we identify a possible involvement of GluA2-lacking Ca2+-permeable AMPA receptors (CP-AMPARs) using IEM-1460, which has been shown to block GluA2-lacking AMPARs. In CBA/CaJ mice, a 2-h exposure to 100-dB sound pressure level octave band (8 to 16 kHz) noise results in no permanent threshold shift but does cause significant synaptopathy and a reduction in auditory brainstem response (ABR) wave-I amplitude. Chronic intracochlear perfusion of IEM-1460 in artificial perilymph (AP) into adult CBA/CaJ mice prevented the decrease in ABR wave-I amplitude and the synaptopathy relative to intracochlear perfusion of AP alone. Interestingly, IEM-1460 itself did not affect the ABR threshold, presumably because GluA2-containing AMPARs can sustain sufficient synaptic transmission to evoke low-threshold responses during blockade of GluA2-lacking AMPARs. On individual postsynaptic densities, we observed GluA2-lacking nanodomains alongside regions with robust GluA2 expression, consistent with the idea that individual synapses have both CP-AMPARs and Ca2+-impermeable AMPARs. SGNs innervating the same IHC differ in their relative vulnerability to noise. We found local heterogeneity among synapses in the relative abundance of GluA2 subunits that may underlie such differences in vulnerability. We propose a role for GluA2-lacking CP-AMPARs in noise-induced cochlear synaptopathy whereby differences among synapses account for differences in excitotoxic susceptibility. These data suggest a means of maintaining normal hearing thresholds while protecting against noise-induced synaptopathy, via selective blockade of CP-AMPARs.

Targeting apoptosis and autophagy by a novel bcl-2 inhibitor, GX15-070, in neuroblastoma.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 10048-10048
Author(s):  
Herve Sartelet ◽  
Sonia Cournoyer ◽  
Anissa Addioui ◽  
Assila Belounis ◽  
Mona Beaunoyer ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Survival ◽  
Annexin V ◽  
High Sensitivity ◽  
Western Blots ◽  
Pediatric Tumor ◽  
Nsg Mice ◽  
Apoptotic Protein

10048 Background: Neuroblastoma (NB) is a frequent pediatric tumor with poor prognosis. The disregulation of the anti-apoptotic protein Bcl-2 is crucial for the tumoral development and chemoresistance. Autophagy is also implicated in tumor cell survival and chemoresistance. The aim of our study was to demonstrate the in vitro and in vivo therapeutic efficiency of GX 15-070, a Bcl-2 inhibitor, used alone and in combination with conventional drugs used in the treatment of NB and hydroxychloroquine (HCQ), a known autophagy inhibitor. Methods: Using 6 NB cell lines, cell viability (MTT) assays were done at progressively increased concentrations of GX 15-070 alone or in combination with cisplatin or with Z-VAD-FMK, a broad-spectrum caspase inhibitor. Apoptosis was tested by evaluating the cleavage of caspase 3 by western blots (WB) and the Annexin V/7-AAD staining studied by FACS. To assess if autophagy was modified by GX 15-070, the cleavage of LC3 protein was tested by WB and cell survival were tested with combination of GX 15-070 and HCQ. To verify the anti-tumor activity in vivo of GX 15-070, orthotopic injections were made on NSG mice treated with GX 15-070 alone and in combination with HCQ. Results: It was observed a high sensitivity of the NB cells to GX 15-070 with increase of cell death and a potential synergistic of this molecule when it’s combined with cisplatin or HCQ. This cell death was due to apoptosis and may also be inhibited by Z-VAD-FMK. GX 15-070 alone or associated to cisplatin increased the autophagy. The in vivo study showed that GX 15-070 treatment used alone or in combination with HCQ significantly decreased the size of the tumor. Conclusions: Our results support the interest of GX 15-070 in the treatment of NB alone or in combination with classical drugs. Our studies also support that activation of apoptosis associated with inhibition of autophagy have a synergistic potential against tumoral progression and must have to be considered in further mechanistic studies for the optimization of more efficient combined therapies in the treatment of NB.

scholarly journals Association of the Kv1 family of K+ channels and their functional blueprint in the properties of auditory neurons as revealed by genetic and functional analyses

2013 ◽  
Vol 110 (8) ◽  
pp. 1751-1764 ◽  
Author(s):  
Wenying Wang ◽  
Hyo Jeong Kim ◽  
Ping Lv ◽  
Bruce Tempel ◽  
Ebenezer N. Yamoah
Keyword(s):  
Membrane Potential ◽  
Developmental Plasticity ◽  
Spiral Ganglion ◽  
Membrane Properties ◽  
Resting Membrane Potential ◽  
Underlying Mechanisms ◽  
Null Mutant Mice ◽  
Ganglion Neurons

Developmental plasticity in spiral ganglion neurons (SGNs) ensues from profound alterations in the functional properties of the developing hair cell (HC). For example, prehearing HCs are spontaneously active. However, at the posthearing stage, HC membrane properties transition to graded receptor potentials. The dendrotoxin (DTX)-sensitive Kv1 channel subunits (Kv1.1, 1.2, and 1.6) shape the firing properties and membrane potential of SGNs, and the expression of the channel undergoes developmental changes. Because of the stochastic nature of Kv subunit heteromultimerization, it has been difficult to determine physiologically relevant subunit-specific interactions and their functions in the underlying mechanisms of Kv1 channel plasticity in SGNs. Using Kcna2 null mutant mice, we demonstrate a surprising paradox in changes in the membrane properties of SGNs. The resting membrane potential of Kcna2−/− SGNs was significantly hyperpolarized compared with that of age-matched wild-type (WT) SGNs. Analyses of outward currents in the mutant SGNs suggest an apparent approximately twofold increase in outward K+ currents. We show that in vivo and in vitro heteromultimerization of Kv1.2 and Kv1.4 α-subunits underlies the striking and unexpected alterations in the properties of SGNs. The results suggest that heteromeric interactions of Kv1.2 and Kv1.4 dominate the defining features of Kv1 channels in SGNs.

scholarly journals Contralateral Suppression of DPOAEs in Mice after Ouabain Treatment

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Jieying Li ◽  
Yan Chen ◽  
Shan Zeng ◽  
Chuijin Lai ◽  
Yanping Zhang ◽  
...  
Keyword(s):  
Otoacoustic Emissions ◽  
Round Window ◽  
Spiral Ganglion ◽  
Auditory Brainstem ◽  
Spiral Ganglion Neurons ◽  
Type I ◽  
Type Ii ◽  
Contralateral Suppression ◽  
Brainstem Response ◽  
Ganglion Neurons

Medial olivocochlear (MOC) efferent feedback is suggested to protect the ear from acoustic injury and to increase its ability to discriminate sounds against a noisy background. We investigated whether type II spiral ganglion neurons participate in the contralateral suppression of the MOC reflex. The application of ouabain to the round window of the mouse cochlea selectively induced the apoptosis of the type I spiral ganglion neurons, left the peripherin-immunopositive type II spiral ganglion neurons intact, and did not affect outer hairs, as evidenced by the maintenance of the distorted product otoacoustic emissions (DPOAEs). With the ouabain treatment, the threshold of the auditory brainstem response increased significantly and the amplitude of wave I decreased significantly in the ouabain-treated ears, consistent with the loss of type I neurons. Contralateral suppression was measured as reduction in the amplitude of the 2f1−f2 DPOAEs when noise was presented to the opposite ear. Despite the loss of all the type I spiral ganglion neurons, virtually, the amplitude of the contralateral suppression was not significantly different from the control when the suppressor noise was delivered to the treated cochlea. These results are consistent with the type II spiral ganglion neurons providing the sensory input driving contralateral suppression of the MOC reflex.

scholarly journals Anti-PD-1 Therapy Does Not Influence Hearing Ability in the Most Sensitive Frequency Range, but Mitigates Outer Hair Cell Loss in the Basal Cochlear Region

2020 ◽  
Vol 21 (18) ◽  
pp. 6701
Author(s):  
Judit Szepesy ◽  
Gabriella Miklós ◽  
János Farkas ◽  
Dániel Kucsera ◽  
Zoltán Giricz ◽  
...  
Keyword(s):  
Outer Hair Cell ◽  
Checkpoint Inhibitors ◽  
Spiral Ganglion ◽  
Auditory Brainstem ◽  
Outer Hair Cells ◽  
Antibody Treatment ◽  
High Frequency Region ◽  
Age Related ◽  
Brainstem Response ◽  
Ganglion Neurons

The administration of immune checkpoint inhibitors (ICIs) often leads to immune-related adverse events. However, their effect on auditory function is largely unexplored. Thorough preclinical studies have not been published yet, only sporadic cases and pharmacovigilance reports suggest their significance. Here we investigated the effect of anti-PD-1 antibody treatment (4 weeks, intraperitoneally, 200 μg/mouse, 3 times/week) on hearing function and cochlear morphology in C57BL/6J mice. ICI treatment did not influence the hearing thresholds in click or tone burst stimuli at 4–32 kHz frequencies measured by auditory brainstem response. The number and morphology of spiral ganglion neurons were unaltered in all cochlear turns. The apical-middle turns (<32 kHz) showed preservation of the inner and outer hair cells (OHCs), whilst ICI treatment mitigated the age-related loss of OHCs in the basal turn (>32 kHz). The number of Iba1-positive macrophages has also increased moderately in this high frequency region. We conclude that a 4-week long ICI treatment does not affect functional and morphological integrity of the inner ear in the most relevant hearing range (4–32 kHz; apical-middle turns), but a noticeable preservation of OHCs and an increase in macrophage activity appeared in the >32 kHz basal part of the cochlea.

Artemin improves survival of spiral ganglion neurons in vivo and in vitro

Neuroreport ◽  
2010 ◽  
Vol 21 (7) ◽  
pp. 517-521 ◽  
Author(s):  
Athanasia Warnecke ◽  
Verena Scheper ◽  
Ines Buhr ◽  
Gentiana I. Wenzel ◽  
Kirsten Wissel ◽  
...  
Keyword(s):  
Spiral Ganglion ◽  
Spiral Ganglion Neurons ◽  
Ganglion Neurons
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