The Olfactory Epithelium (OE) is an essential component of the olfactory system, responsible of detecting and transmitting odor signals. Under homeostatic conditions, this tissue has the capacity to regenerate after damage. However, diseases or infections can severely affect this ability, leading to debilitating impairment of the olfactory function. The OE, located in the olfactory cleft, is composed by basal stem cells, sustentacular cells and Olfactory Sensory Neurons (OSNs), laid over a lamina propria rich in fibroblasts and immunosurveilled by macrophages.
To study OE infections in vitro in a physiological system, we intend to generate a 3D immunocompetent model using primary cells from human biopsies. Olfactory stem cells will be differentiated into OSNs. The OE cell lineages (OSNs, sustentacular and stem cells) will be seeded on top of a collagen matrix containing fibroblasts and monocyte-derived macrophages, reproducing the lamina propria.
First, we focused on harvesting mucosal cells from olfactory cleft brushings, a relatively non-invasive procedure performed during surgeries of the nasal cavity. We identified epithelial and stem cells, that were subsequently expanded and characterized. Freshly isolated cells included 30-45% epithelial cells (CK19, EpCAM) and ~8% neural stem cells (Nestin). Upon expansion in epithelial growth medium, epithelial cells represented over 80% of the culture and stem cells were still present.
We are currently testing the potential of these cells to colonize a collagen matrix and generate an epithelium. Altogether, we expect to mimic the structural and functional anatomy of human olfactory mucosa, providing a relevant model to investigate infections, pathogenesis, and immunity.