Noise exposure induces autophagy-modulated nuclear-to-cytoplasmic translocation of TDP-43 in spiral ganglion neurons.

Abstract

Noise exposure contributes to approximately one-third of hearing loss cases worldwide. Despite its substantial global burden, noise-induced hearing loss (NIHL) remains essentially irreversible, largely because its underlying pathogenic mechanisms are not yet fully defined. In this study, we established three noise-induced hearing loss mouse models and evaluated auditory function by measuring auditory brainstem response (ABR) thresholds at multiple time points following noise exposure. In parallel, we examined the spatiotemporal redistribution of TDP-43 and evaluated autophagic flux in spiral ganglion neurons (SGNs) to elucidate their dynamic responses to acoustic stress. Noise exposure triggers marked nucleocytoplasmic translocation and cytoplasmic aggregation of TDP-43 in spiral ganglion neurons (SGNs), accompanied by dynamic alterations in autophagic flux. Using pharmacological modulation, we demonstrate that autophagy critically shapes the fate of TDP-43. Mechanistically, noise-induced stressors such as reactive oxygen species (ROS) likely initiate TDP-43 nuclear export, whereas insufficient autophagic flux impedes aggregate degradation and exacerbates cytoplasmic inclusion formation. Together, these findings reveal autophagy as a key determinant of TDP-43 dynamics in the auditory system and identify the autophagy-TDP-43 axis as a potential therapeutic target for preventing or ameliorating noise-induced hearing loss.