An in vitro model of murine middle ear epithelium.

Otitis media (OM) or middle ear inflammation is the most common pediatric disease and leads to significant morbidity. Although understanding of underlying disease mechanisms is hampered by complex pathophysiology it is clear that epithelial abnormalities underpin the disease. There is currently a lack of a well characterised in vitro model of the middle ear (ME) epithelium that replicates the complex cellular composition of the middle ear. Here we report the development of a novel in vitro model of mouse middle ear epithelial cells (mMECs) at air liquid interface (ALI) that recapitulates the characteristics of the native murine ME epithelium. We demonstrate that mMECs undergo differentiation into the varied cell populations seen within the native middle ear. Proteomic analysis confirmed that the cultures secrete a multitude of innate defence proteins from their apical surface. We could show that the mMECs supported the growth of the otopathogen, NTHi, suggesting that the model can be succesfully utilised to study host pathogen interactions in the middle ear. Overall, our mMEC culture system can help better understand the cell biology of the middle ear and improve our understanding of the pathophysiology of OM. The model also has the potential to serve as a platform for validation of treatments designed to reverse aspects of epithelial remodelling underpinning OM development.