Human middle ear epithelium is permissive to infection with SARS-CoV-2

ABSTRACT NUMBER: FEGGETTER MEDAL FOR SENIOR TRAINEES (ST3+)_5

 

AUTHOR
Michael Mather

MAIN ABSTRACT TEXT

Introduction
Otitis media (OM) is a leading cause of consultations and surgery in children (Schilder et al., 2016) but translational advances have been hampered by the lack of a physiological model of middle ear epithelium (MEE). Immortalised cell lines (Chun et al., 2002) and animals models (Bhutta, 2012) exist, but do not recapitulate the MEE phenotype in vivo. The effect of SARS-CoV-2 on MEE is also unknown, but may be significant due to close proximity to the nasopharynx via the Eustachian tube.

Methods
Culture of human MEE at an air-liquid interface, akin to the healthy ventilated middle ear – validated using immunofluorescence, electron microscopy, membrane conductance studies (Ussing chamber), and live-cell bioimaging. We also infected cells with SARS-CoV-2 and assessed viral uptake (polymerase-chain reaction/immunohistochemistry).

Results
Over 3 weeks a fully differentiated cell line demonstrates production of mucin (MUC5AC, MUC5B), cilia (FOXJ1), tight junctions, and typical epithelial markers (cytokeratin/p63). Membrane conductance was consistent with respiratory epithelium. Bioimaging studies revealed motile cilia. These findings reflect the cell types seen in vivo. Cells were positive for SARS-CoV-2 following viral challenge.

Conclusion
We present a novel MEE cell line which recapitulates the in vivo phenotype which will be useful for research into OM and related middle ear diseases. Further, we demonstrate MEE is capable of SARS-CoV-2 infection within 24 hours of viral exposure, which has important implications for safe otological surgery and possibly atypical presentations of SARS-CoV-2 in children.