Liproxstatin-1 Protects Hair Cell-Like HEI-OC1 Cells and Cochlear Hair Cells against Neomycin Ototoxicity.

Zhiwei Zheng,Dongmei Tang,Guohui Nie,Wen Li,Yingzi He,Liping Zhao,Jinghong Han,Bing Hu,Danina Muntean

doi:10.1155/2020/1782659

Abstract

Ferroptosis is a recently discovered iron-dependent form of oxidative programmed cell death distinct from caspase-dependent apoptosis. In this study, we investigated the effect of ferroptosis in neomycin-induced hair cell loss by using selective ferroptosis inhibitor liproxstatin-1 (Lip-1). Cell viability was identified by CCK8 assay. The levels of reactive oxygen species (ROS) were determined by DCFH-DA and cellROX green staining. The mitochondrial membrane potential (ΔΨm) was evaluated by TMRM staining. Intracellular iron and lipid peroxides were detected with Mito-FerroGreen and Liperfluo probes. We found that ferroptosis can be induced in both HEI-OC1 cells and neonatal mouse cochlear explants, as evidenced by Mito-FerroGreen and Liperfluo staining. Further experiments showed that pretreatment with Lip-1 significantly alleviated neomycin-induced increased ROS generation and disruption in ΔΨm in the HEI-OC1 cells. In parallel, Lip-1 significantly attenuated neomycin-induced hair cell damage in neonatal mouse cochlear explants. Collectively, these results suggest a novel mechanism for neomycin-induced ototoxicity and suggest that ferroptosis inhibition may be a new clinical intervention to prevent hearing loss.

Highlights

Hearing loss can be caused by ototoxic pharmaceutical agents, excessive noise, genetic disorders, and aging
To test whether ferroptosis is induced in HEI-OC1 cells, twentyfour hours after the start of the HEI-OC1 cell culture, we replaced the culture medium with fresh medium with Ras-selective lethal 3 (RSL3), a ferroptosis inducer, at increasing concentrations for 12 h, h, and 48 h (Figures 1(a)–1(c))
For 24 h significantly reduced the cell viability to ~50% compared with the nontreated controls; a RSL3 concentration of 3 μM was used for the subsequent experiments

Summary

Introduction

Hearing loss can be caused by ototoxic pharmaceutical agents, excessive noise, genetic disorders, and aging. The crucial mechanism responsible for aminoglycoside-induced ototoxicity is oxidative stress [3]. Overproduction of reactive oxygen species (ROS) resulting from oxidative stress overwhelms the ROS defense and disturbs the redox balance, triggering mitochondrial depolarization, activating caspase, and eventually inducing hair cell injury [1, 4]. This mechanism is not exclusively responsible for aminoglycoside-induced hair cell death [5,6,7]. Better understanding of the mechanisms of aminoglycosideinduced ototoxicity is crucial for developing a new promising treatment strategy to prevent hearing loss

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Discussion

Conclusion