Quaking dysregulation contributes to demyelination and functional decline of the mouse auditory nerve after noise exposure

Myelinating glia in the auditory system enclose auditory nerve fibers, providing an insulating effect that facilitates rapid transfer of auditory information from the ear to the brain. Here we show that noise exposure at the levels sufficient for inducing hearing loss cause a rapid cellular and molecular response on myelinating glia that precedes neuron degeneration. The response is characterized by inflammatory response, myelin dysmorphology and widespread changes in myelin-related gene expression. Another characteristic was change in expression of the quaking gene (QKI), which encodes a group of RNA binding proteins that are enriched in myelinating glia. Changes in QKI were accompanied by changes in numerous known and potential QKI target genes, including many genes associated with myelination. Our results implicate QKI as a critical early component in the noise response, influencing glia dysfunction that leads to auditory nerve demyelination and, ultimately, sensorineural hearing loss.

15