27 April 2020
Scientists identify key cells as the entry point for Covid-19.
Muriel Cozier
Researchers believe that two specific cells in the nose are the most likely initial infection point for Covid-19. The goblet and ciliated cells have high levels of proteins that Covid-19 uses to get into the cells of the body, which researchers believe could explain the high transmission rate.
This new information comes as a result of the work carried out as part of the Human Cell Atlas Lung Biological Network which brings together scientists from a number of bodies including the Wellcome Sanger Institute and the University Cote d’Azur.
Publishing their findings in Nature Medicine, the researchers also indicate that cells in the eye and some other organs also contain the viral entry point proteins. The study also predicts how a key entry protein is regulated with other immune system genes and reveals potential targets for the development of treatments to reduce transmission.
To discover which cells were likely to be involved in Covid-19 transmission, the research team analysed multiple Human Cell Atlas (HCA) consortium datasets of single cell RNA sequencing from more than 20 different tissues of non-infected people. These included cells from the lung, nasal cavity, eye, gut, heart, kidney and liver. The researchers looked for which individual cells expressed both of the two key entry proteins, these being ACE2 and TMPRSS2. As well as the nose these proteins were found in the cells of the cornea, and in the lining of the intestine. This, the researchers say, suggests infection routes via the eye and tear ducts and also the potential for faecal-oral transmission.
Professor Jayaraj Rajagopal, a pulmonologist in the Department of Internal Medicine at Massachusetts General Hospital and a Member of the Human Cell Atlas Lung Biological Network commented: ‘The cellular basis of the disease often does not receive as much attention as the molecular basis of disease, even though molecules and cells are inseparably linked. In the case of Covid-19, knowing the cells that act as portals of viral entry and possible viral reservoirs helps us think about why a virus can be transmitted easily between people and why only some people progress to a lethal pneumonia. Most studies of coronaviruses don’t use cells from actual tissues that are infected in patients. The HCA hopes to point both virologists and physicians toward the right cells and tissues for study.’
Nature Medicine DOI: 10.1038/s41591-020-0868-6
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