A Protocol for Neuralized Murine Olfactory Organoids

Chronic olfactory dysfunction can be associated with parkinsonism, dementia, demyelinating disorders and schizophrenia. The olfactory epithelium (OE) represents an interface between the environment and the central nervous system. Mounting evidence implicates environmental factors in neurodegenerative disease processes, necessitating investigations into their interactions with the hosts genome. In Parkinson disease, hyposmia often precedes motor symptoms, raising the possibility that the OE could be involved in disease initiation. We previously demonstrated abundant -synuclein expression in mammalian OE as well as aggregate formation in the olfactory nerve. Current in vitro models of OE are limited, relying primarily on post-mitotic cultures established from biopsies. To address this gap, we present a method for generating olfactory organoids of OE from adult mice. These organoids comprise neuronal and non-neuronal cell types, including sustentacular cells, thus encompassing structural elements of OE in situ. Expression of the olfactory sensory neuron marker OMP and Parkinsons-linked -synuclein was also detected in olfactory organoids, highlighting their potential usefulness to mechanistic research. We established OE organoids that were kept in culture for up to 3 weeks. In addition, we inoculated organoids with the neurotropic vesicular stomatitis virus to model infections. We conclude that this olfactory organoid model system offers a new platform for studying airborne environmental factors in their interactions with a genetically defined host; this, to study OE biology and enable the exploration of disease processes within olfactory tissue.