SARS-CoV-2 infection of non-neuronal cells, not neurons, may drive loss of smell in clients with COVID-19

A brand-new research study of human olfactory cells has actually exposed that viral intrusion of helpful cells in the nasal cavity may be driving the loss of odor seen in some clients with COVID-19 The findings reveal that non-neuronal cells in the brain and nose express genes critical for SARS-CoV-2 entry, while nerve cells do not; therefore, non-neuronal cells are likely to be the primary targets for virus-induced damage leading to loss of odor, or anosmia. Recent investigations into COVID-19- associated anosmia revealed that cells from the human upper air passage express high levels of receptor genes associated with SARS-CoV-2 entry, suggesting that these breathing epithelial cells function as viral reservoirs during CoV-2 infection. These research studies did not investigate the sheet of cells that line the nasal cavity, called the olfactory epithelium – the very first entryway for pathogens before they reach the respiratory epithelium. Utilizing bulk RNA sequencing of human cells from the nasal mucosa, David Brann and colleagues recognized cell enters the olfactory epithelium in the nose and the brain’s olfactory bulb that express two essential receptor genes associated with SARS-CoV-2 entry, ACE2 and TMPRSS2. Single cell RNA sequencing of these cells and neurons supplied the crucial insight that neither gene was identified in olfactory neurons, but both were highly expressed by support cells, stem cells, and perivascular cells in the nose and brain. Fluorescent staining of ACE2 in olfactory cells in mice verified this outcome and revealed pervasive expression of ACE2 protein in structural support cells of the nose and in cells that wrap around the blood vessels of the olfactory bulb. Identifying the systems that underlie the olfactory signs of COVID-19 can help lead to new diagnostics for SARS-CoV-2 infection, yield insights into the cellular dynamics of the nose, and propel future treatments for anosmia, the authors say.

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https://covid19globalcases.com/sars-cov-2-infection-of-non-neuronal-cells-not-neurons-may-drive-loss-of-smell-in-clients-with-covid-19/