Transcriptomic comparison of avian auditory and vestibular sensory epithelia.

Our inner ears contain various hair cell subtypes with distinct cytomorphologies, innervation, and functions. Here, we computationally compared hair cell transcriptomes from the avian hearing organ, the basilar papilla, and the utricle, a vestibular organ, to explore how these subtypes differ in gene expression within a single species. We identified distinct gene expression patterns in auditory and vestibular hair cell subgroups. Next, we integrated existing transcriptomic datasets from regenerated nascent auditory hair cells and nascent utricle hair cells arising during natural turnover. We found that while nascent hair cells possess unique transcriptomic profiles, they are more similar to utricular type II hair cells than to their mature functional counterparts. Additionally, three weeks after aminoglycoside-induced hair cell loss in the utricle, the regenerated hair cells lacked type I hair cell gene expression properties. This study provides fundamental insights into avian hair cell diversity and offers a basis for cross-species comparative studies.