Loss of Cisd2 Exacerbates the Progression of Age-Related Hearing Loss.

Age-related hearing loss (ARHL) is a disease that impacts human quality of life and contributes to the progression of other neuronal problems. Various stressors induce an increase in free radicals, destroy mitochondria to further contribute to cellular malfunction, and compromise cell viability, ultimately leading to functional decline. Cisd2, a master gene for Marfan syndrome, plays an essential role in maintaining mitochondrial integrity and functions. As shown by our data, specific deletion of Cisd2 in the cochlea exacerbated the hearing impairment of ARHL in C57BL/6 mice. Increased defects in mitochondrial function, potassium homeostasis and synapse activity were observed in the Cisd2-deleted mouse models. These mechanistic phenotypes combined with oxidative stress contribute to cell death in the whole cochlea. Human patients with obviously deteriorated ARHL had low Cisd2 expression; therefore, Cisd2 may be a potential target for designing therapeutic methods to attenuate the disease progression of ARHL.