miR-145b/AP2B1 Axis Contributes to Noise-induced Sensorineural Hearing Loss In a Male Mouse Model

Sensorineural hearing loss (SNHL) is an increasingly prevalent sensory disorder, but the underlying mechanisms remain poorly understood. Adaptor related protein complex 2 subunit beta 1 (AP2B1) has been indicated to be detectable in mature cochleae. Nonetheless, it is unclear whether AP2B1 is implicated in the progression of SNHL. Male CBA/J mice were exposed to 2-20 kHz broadband noise at 96 or 101 dB SPL to induce temporary or permanent threshold shifts (TTS or PTS). Auditory brainstem responses were measured for hearing loss evaluation. Bioinformatics analysis was used to predict the upstream miRNAs of Ap2b1. RT-qPCR and western blotting were utilized to determine miR-145b and AP2B1 expression in mouse cochleae. Luciferase reporter assay was implemented to verify the interaction between Ap2b1 and miR-145b. Bioinformatics analysis identified miR-145b as an upstream miRNA of Ap2b1. AP2B1 expression was decreased and miR-145b expression was increased in mouse cochleae after PTS noise exposure. miR-145b targeted and negatively regulated Ap2b1 in PTS noise-exposed mice. Depletion of miR-145b alleviated auditory threshold shifts and outer hair cell loss in mice with exposure to PTS noise. In conclusion, inhibition of miR-145b ameliorates noise-induced SNHL in mice by upregulating AP2B1 expression.