Mitophagy Impairment Aggravates Cisplatin-Induced Ototoxicity

Abstract

Cisplatin is an efficacious anticancer agent, but its use is limited by ototoxicity and resultant irreversible sensorineural hearing loss. Cisplatin ototoxicity is associated with cochlear cell oxidative stress and mitochondrial damage. However, mitophagy is vital for maintaining mitochondrial quality and cellular metabolism. Accordingly, we investigated the role of mitophagy in regulating cisplatin-induced ototoxicity using the auditory cell line HEI-OC1. In this study, HEI-OC1 cells were treated with either cisplatin alone (10 μM, 0, 8, 16, and 24 h); cisplatin (10 μM, 24 h) post transfection with small-interfering (si)RNAs targeting mitophagy-associated mRNAs; cisplatin (10 μM, 24 h) succeeding pretreatment with the mitophagy suppressor, 3-methyladenine (3-MA; 5 or 10 mM, 6 h); or cisplatin (30 μM, 24 h) following pretreatment with the mitophagy promoter, carbonyl cyanide m-chlorophenylhydrazone (CCCP; 1 or 2 μM, 2 h). The viability of cells, expression of mitophagy marker, and mitochondrial functions were then assessed in these cells. Cell viability was determined by a water-soluble tetrazolium assay; expression of mitophagy-associated proteins PINK1, Parkin, BNIP3, FUNDC1, p62, and LC3B was analyzed by Western blotting, mitochondrial membrane potential by flow cytometry, intracellular ATP by spectrophotometry, and mitochondrial degradation by dual staining for mitochondria and autophagosomes or lysosomes. Our results showed that cisplatin gradually reduced the viable cell number over time, induced mitochondrial depolarization, decreased intracellular ATP concentration, and enhanced the expression of PINK1, Parkin, BNIP3, p62, and LC3B. In addition, Parkin and BNIP3 knockdown accelerated cisplatin-induced loss of cell viability, mitochondrial membrane potential, mitophagosome/lysosome formation, and reduction in intracellular ATP production. Pretreatment with 3-MA aggravated the cisplatin-induced cytotoxicity, while that with CCCP reversed this effect. Overall, our findings indicate that mitophagy protects HEI-OC1 cells against cisplatin-induced cell death. Consequently, we strongly believe that targeted promotion of mitophagy may confer protection against cisplatin-induced ototoxicity.

Gipc3 Mutation Might Cause Sensorineural Hearing Loss by Inhibiting Mitophagy in Inner Ear Hair Cells

“…Studies have revealed a tight relationship between mitophagy and SNHL, as well as the signi cance of mitophagy in preserving inner ear homeostasis (Zhang et al 2023). According to several studies, impairment of mitophagy can worsen hearing loss brought on by medications and other variables (Cho et al 2021;Kim et al 2021;Li et al 2023a), and up-regulation of mitophagy can reduce drug-induced ototoxic damage (Han et al 2023). The process of mitochondrial ssion is critical for mitophagy.…”

Curcumin-Encapsulated Chitosan-Coated Nanoformulation as an Improved Otoprotective Strategy for Ototoxic Hearing Loss

“…Although low CUR and CUR-NP concentrations could protect OHCs from CDDP damage, the exact mechanism responsible for this protection remains unclear. CDDP is known to promote endogenous mitochondrial damage and HC apoptosis via upregulation of oxidative stress, which eventually leads to ototoxicity. , Additional reports revealed that enhanced ROS synthesis was a primary mechanism that regulates ototoxic drug-driven HC apoptosis. Excess ROS inhibits HC activity, impairs antioxidant defense, and promotes the mitochondrial release of the apoptotic factor cytochrome C. − Mitochondrial apoptosis involves regulation by both pro- and antiapoptotic members of the Bax family of proteins, and Caspase-3 is the ultimate target of this process .…”

miR-34a/DRP-1-mediated mitophagy participated in cisplatin-induced ototoxicity via increasing oxidative stress

“…Currently,cisplatin induced ototoxicity is a major obstacles that limited the maximum e cacy for tumor patients.Previously studies demonstrated that miRNA was closely associated with hearing loss and considered as promising therapeutic targets [29] .A currently study reported mitophagy protected HEI-OC1 cells against cisplatin-induced ototoxicity [30] ,but the precise molecular mechanism remained to be further studied.In the present study,we investigated whether miR-34a/DRP1-meditaed mitophagy contributed to cisplatin-induced ototoxicity and sought to determined the underlying mechanism.…”

“…HEI-OC1 cells were treated with various concentration cisplatin (10,20,30, and 40 uM) and detected the cell viability at 8,16,24, and 48 h after exposure.CCK-8 assay indicated that cisplatin exposure induced cytotoxicity of HEI-OC1 Cells in a dose-time dependent manner (Fig. 3A ).The cell viability was appropriately 45.2% in HEI-OC1 cell treated with 20 uM cisplatin for 24 h.Therefore,we chose 20 um cisplatin for 24h as the exposure concentration and time of the subsequent experiments.…”