Mesenchymal predominance in olfactory epithelium-derived cultures limits modeling of neurodevelopmental brain disorders
The human olfactory epithelium (OE) represents a lifelong source of neural progenitor cells and has been proposed as an accessible model to investigate molecular alterations associated with neurodevelopmental disorders in postnatal individuals. Globose basal cells are considered the immediate neuronal progenitors within the OE, and several studies have attempted to culture these cells from nasal exfoliates. However, the actual contribution of neurogenic lineages in these cultures remains largely unquantified. Here, we cultured human nasal explants using an established protocol and characterized the resulting cell populations by immunohistochemistry and single-cell RNA sequencing. Integration with primary in vivo OE datasets revealed that these cultures are predominantly composed of mesenchymal-like cells, with limited representation of globose basal cells and neurons, and low expression of canonical neuronal markers. Using curated gene sets associated with neurodevelopmental disorders and malformations of cortical development, we assessed the extent to which disease-relevant transcriptional programs are captured in OE-derived cultures. While disease-associated genes are enriched in neurogenic lineages in vivo, their representation in mesenchymal cells is reduced. Together, our results challenge the assumption that standard OE culture systems faithfully model neurogenic compartments and suggest that current approaches may need refinement to recover neurogenic lineages.