Identification and characterization of taste cells in saliva to investigate post-COVID dysgeusia 3942

Description The frequent complaints of taste dysfunction in the recent COVID-19 pandemic are well reported. Persistent loss of taste in post-COVID sequel even in adolescents could impact the systemic health of larger population. Subjective and objective taste testing by several reports including ours suggest that bitter and sweet tastes are more often affected in SARS-CoV2 infected individuals. The TAS2R38 gene is linked to bitter taste perception in taste bud cells and to eliciting immune responses in non-gustatory tissues. Initial characterization of TAS2R38 polymorphism was not conclusive with respect to objective taste testing in our post-COVID cohort. We then hypothesized that an imbalanced taste cell turnover with increased loss due to persistent inflammation secondary to CoV2 infection leads to dysgeusia. We performed single cell transcriptomic analysis of two control (pre-COVID) and three post-COVID saliva samples. Significantly, we identified not only epithelial and immune cells in saliva, but also cells expressing neuronal markers such as SNAP25, PLCβ2 and KCNQ2 indicating the presence of taste receptor cells. Different gene expression approached significance for some taste receptor genes (TAS1R1, TAS2R14) and inflammatory genes. Taste cells and inflammation in saliva were validated by confocal microscopy, flow cytometry and cytokine quantitation. Taken together, persistent neuroepithelial immune responses that alter taste bud turnover contributes to post-COVID dysgeusia. Funding Sources Delta Dental Research Foundation: #44-762-54 Topic Categories Immune Mechanisms of Human Disease (HUM)