Obacunone mitigates cisplatin-induced ototoxicity by activating CRHBP-mediated autophagy

Cisplatin, a widely used antitumor agent, is limited in clinical application due to its ototoxicity. This study investigates the protective effects of obacunone, an active compound from Phellodendron bark, against cisplatin-induced hearing loss. Obacunone significantly improved the survival of cisplatin-treated House Ear Institute-Organ of Corti 1 (HEI-OC1) cells, preserved the cochlear explant, and enhanced auditory function in mice upon cisplatin treatment. Mechanistically, obacunone inhibited cisplatin-induced apoptosis by activating autophagy. Transcriptome profiling revealed that the expression of corticotropin-releasing hormone-binding protein (CRHBP) was increased in the cisplatin and obacunone co-treated group compared to the cisplatin-only group. Overexpression of CRHBP significantly enhanced autophagy and inhibited apoptosis, mirroring the effects of obacunone. Our findings demonstrate that obacunone promotes autophagy by upregulating CRHBP, thereby reducing cisplatin-induced hair cell apoptosis. This study provides a novel therapeutic strategy using the natural product obacunone for preventing cisplatin-induced hearing loss and highlights the potential of CRHBP as a target for otoprotective interventions.