The adult mouse utricle as an in vitro preparation for studies of ototoxic-drug-induced sensory hair cell death

Cunningham, Lisa L.

doi:10.1016/j.brainres.2006.01.128

Cited by 42 publications

(33 citation statements)

References 28 publications

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“…The adult mouse utricle preparation has been previously described in detail . 26,48 Briefly, temporal bones were removed from adult Atoh1-Cre x Rosa26-tdTomato transgenic mice of both sexes (4-12 weeks old) and placed in sterile M199 (Life Technologies Corporation, Carlsbad, CA, USA). Utricles were then dissected under sterile conditions and otoconia were removed with an eyelash tool (Ted Pella, Redding, CA, USA).…”

Section: Methodsmentioning

confidence: 99%

Live imaging the phagocytic activity of inner ear supporting cells in response to hair cell death

et al. 2015

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Hearing loss and balance disorders affect millions of people worldwide. Sensory transduction in the inner ear requires both mechanosensory hair cells (HCs) and surrounding glia-like supporting cells (SCs). HCs are susceptible to death from aging, noise overexposure, and treatment with therapeutic drugs that have ototoxic side effects; these ototoxic drugs include the aminoglycoside antibiotics and the antineoplastic drug cisplatin. Although both classes of drugs are known to kill HCs, their effects on SCs are less well understood. Recent data indicate that SCs sense and respond to HC stress, and that their responses can influence HC death, survival, and phagocytosis. These responses to HC stress and death are critical to the health of the inner ear. Here we have used live confocal imaging of the adult mouse utricle, to examine the SC responses to HC death caused by aminoglycosides or cisplatin. Our data indicate that when HCs are killed by aminoglycosides, SCs efficiently remove HC corpses from the sensory epithelium in a process that includes constricting the apical portion of the HC after loss of membrane integrity. SCs then form a phagosome, which can completely engulf the remaining HC body, a phenomenon not previously reported in mammals. In contrast, cisplatin treatment results in accumulation of dead HCs in the sensory epithelium, accompanied by an increase in SC death. The surviving SCs constrict fewer HCs and display impaired phagocytosis. These data are supported by in vivo experiments, in which cochlear SCs show reduced capacity for scar formation in cisplatin-treated mice compared with those treated with aminoglycosides. Together, these data point to a broader defect in the ability of the cisplatin-treated SCs, to preserve tissue health in the mature mammalian inner ear. . 4 SCs perform many functions, including providing critical trophic factors, preventing excitotoxicity, and mediating regeneration in those systems (non-mammalian vertebrates) capable of replacing lost HCs. 5-11 When HCs die, SCs also preserve the integrity and function of the remaining tissue by forming scars and clearing dead HCs. 2,12-17 Maintaining a fluid barrier at the surface of the sensory epithelium after damage is necessary to preserve the electro-chemical gradient that drives HC depolarization and therefore sensory transduction after the onset of hearing (reviewed in Wangemann). 18 Several major stressors cause HC death, 19-22 including aging, noise trauma, and exposure to therapeutic drugs with ototoxic side effects. When a HC is killed by noise or aminoglycoside antibiotics, surrounding SCs form a filamentous actin (F-actin) cable that constricts the HC at its apex. 2,[12][13][14][15][16][17] This process separates the apical portion of the cell, including the stereocilia bundle, from the HC body and preserves a sealed reticular lamina. 23 In the chick utricle, following the apical constriction of dead HCs, the SCs engulf and phagocytose the remaining HC corpse. 15 Additional data from the chick indicate that the ototoxi...

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Section: Methodsmentioning

confidence: 99%

Live imaging the phagocytic activity of inner ear supporting cells in response to hair cell death

et al. 2015

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“…Culture of utricles from adult mice has been previously described (Cunningham 2006;Brandon et al 2012). Culture media consisted of either BME/EBSS or DMEM/F12 supplemented with 5 % fetal bovine serum (Invitrogen, Carlsbad, CA, USA) and 50 U/mL penicillin G. Utricles were maintained in an incubator at 37°C in a 5 % CO 2 /95 % air environment.…”

Section: Utricle Culturementioning

confidence: 99%

Heat Shock Protein-Mediated Protection Against Cisplatin-Induced Hair Cell Death

Baker

Roy

Brandon

et al. 2014

JARO

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Cisplatin is a highly successful and widely used chemotherapy for the treatment of various solid malignancies in both adult and pediatric patients. Side effects of cisplatin treatment include nephrotoxicity and ototoxicity. Cisplatin ototoxicity results from damage to and death of cells in the inner ear, including sensory hair cells. We showed previously that heat shock inhibits cisplatin-induced hair cell death in whole-organ cultures of utricles from adult mice. Since heat shock protein 70 (HSP70) is the most upregulated HSP in response to heat shock, we investigated the role of HSP70 as a potential protectant against cisplatin-induced hair cell death. Our data using utricles from HSP70 −/− mice indicate that HSP70 is necessary for the protective effect of heat shock against cisplatin-induced hair cell death. In addition, constitutive expression of inducible HSP70 offered modest protection against cisplatin-induced hair cell death. We also examined a second heat-inducible protein, heme oxygenase-1 (HO-1, also called HSP32). HO-1 is an enzyme responsible for the catabolism of free heme. We previously showed that induction of HO-1 using cobalt protoporphyrin IX (CoPPIX) inhibits aminoglycoside-induced hair cell death. Here, we show that HO-1 also offers significant protection against cisplatin-induced hair cell death. HO-1 induction occurred primarily in resident macrophages, with no detectable expression in hair cells or supporting cells. Depletion of macrophages from utricles abolished the protective effect of HO-1 induction. Together, our data indicate that HSP induction protects against cisplatin-induced hair cell death, and they suggest that resident macrophages mediate the protective effect of HO-1 induction.

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“…The adult mouse utricle preparation has previously been described in detail (Cunningham 2006). There are two types of hair cells in the utricle.…”

Section: Whole-mount Utriclesmentioning

confidence: 99%

“…Adult mouse utricles were dissected under sterile conditions as previously described (Cunningham 2006). Utricles were fixed in 4% paraformaldehyde overnight at 4°C and then washed with PBS.…”

Section: Whole-mount Utriclesmentioning

confidence: 99%

Hsp70 inhibits aminoglycoside-induced hearing loss and cochlear hair cell death

Taleb

Brandon

Lee

et al. 2009

Cell Stress and Chaperones

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Sensory hair cells of the inner ear are sensitive to death from aging, noise trauma, and ototoxic drugs. Ototoxic drugs include the aminoglycoside antibiotics and the antineoplastic agent cisplatin. Exposure to aminoglycosides results in hair cell death that is mediated by specific apoptotic proteins, including c-Jun N-terminal kinase (JNK) and caspases. Induction of heat shock proteins (Hsps) can inhibit JNK-and caspase-dependent apoptosis in a variety of systems. We have previously shown that heat shock results in robust upregulation of Hsps in the hair cells of the adult mouse utricle in vitro. In addition, heat shock results in significant inhibition of both cisplatin-and aminoglycoside-induced hair cell death. In this system, Hsp70 is the most strongly induced Hsp, which is upregulated over 250-fold at the level of mRNA 2 h after heat shock. Hsp70 overexpression inhibits aminoglycoside-induced hair cell death in vitro. In this study, we utilized Hsp70-overexpressing mice to determine whether Hsp70 is protective in vivo. Both Hsp70-overexpressing mice and their wildtype littermates were treated with systemic kanamycin (700 mg/kg body weight) twice daily for 14 days. While kanamycin treatment resulted in significant hearing loss and hair cell death in wild-type mice, Hsp70-overexpressing mice were significantly protected against aminoglycosideinduced hearing loss and hair cell death. These data indicate that Hsp70 is protective against aminoglycoside-induced ototoxicity in vivo.

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The adult mouse utricle as an in vitro preparation for studies of ototoxic-drug-induced sensory hair cell death

Cited by 42 publications

References 28 publications

Live imaging the phagocytic activity of inner ear supporting cells in response to hair cell death

Live imaging the phagocytic activity of inner ear supporting cells in response to hair cell death

Heat Shock Protein-Mediated Protection Against Cisplatin-Induced Hair Cell Death

Hsp70 inhibits aminoglycoside-induced hearing loss and cochlear hair cell death

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