Olfactory Sustentacular Cells (OSCs)

Primary olfactory sustentacular cells (OSCs) are specialized supporting cells located within the pseudostratified olfactory epithelium (OE) that lines the superior nasal cavity. They are columnar cells that extend from the apical epithelial surface to the basal lamina, with their nuclei positioned superficially near the nasal airspace. Alongside olfactory sensory neurons (OSNs), basal cells, and microvillar cells, sustentacular cells constitute one of the major cell populations of the OE.

Historically regarded as passive structural supports, OSCs are now recognized as multifunctional cells essential for olfactory homeostasis. Their apical surfaces are covered with microvilli that intermingle with OSN cilia, and they contribute to the secretion of the mucus layer that protects the dendritic processes. OSCs also provide metabolic support by supplying glucose to olfactory cilia—which lack mitochondria—via glucose transporters, enabling the energy-consuming process of olfactory signal transduction. Additional functions include detoxification of odorants, regulation of ionic composition of the mucus, and expression of odorant-binding proteins.