Cellular diversity of human inner ear organoids revealed by single-cell transcriptomics

Human inner ear organoids are three-dimensional tissular structures grown in vitro that recapitulate some aspects of the fetal inner ear and allow the differentiation of inner ear cell types. These organoids offer a system in which to study human inner ear development, mutations causing hearing loss and vertigo, and new therapeutic drugs. However, the extent to which such organoids mimic in vivo human inner ear development and cellular composition remains unclear. Several recent studies have performed single-cell transcriptomics on human inner ear organoids to interrogate cellular heterogeneity, reveal the developmental trajectories of sensory lineages and compare organoid-derived vesicles to the developing human inner ear. Here, we discuss the new insights provided by these analyses that help to define new paths of investigation to understand inner ear development.