Distinct cochlear cell types associated with genetic susceptibility to sensory and metabolic hearing loss in older...

Hearing loss is a heterogeneous condition that can be classified into different subtypes with diverse genetic and cellular components. To investigate the cochlear cell types underlying the genetic basis of sensory and metabolic components of age-related hearing loss (ARHL), we integrated human genome-wide association study data with mouse cochlear single-cell RNA sequencing data using the single-cell disease relevance score tool. These analyses revealed that genes associated with the sensory component of ARHL were most highly expressed in hair cells, while genes associated with the metabolic component of ARHL were most highly expressed in spiral ganglion neurons. We also investigated whether ARHL-associated gene expression patterns differed across subpopulations of the same cell type. Sensory hearing loss-associated genes showed differential expression across supporting cell subpopulations in younger mice, whereas metabolic hearing loss-associated genes exhibited differences across intermediate cell subpopulations of the stria vascularis in older mice. These findings provide evidence for the role of distinct genetic and cellular risk profiles for different ARHL subtypes, suggesting that prevention and therapeutic strategies may require targeting specific cell populations at different life stages.