Coronavirus Entry Points Identified
Scientists have identified two specific types of cells in the nose likely to be the initial infection points for the Covid-19 virus to enter. They discovered that the cells that have high levels of the entry proteins that the Covid-19 virus uses to enter are the goblet and ciliated cells.
Researchers who identified this are from the Wellcome Sanger Institute, University Cote d’Azur, University Medical Centre Groningen, Nice, CNRS, and their collaborators, as part of the Human Cell Atlas Lung Biological Network. The high rate of transmission of Covid-19 can be explained with the help of this discovery.
To understand infection and disease using Human Cell Atlas data, this publication reported in Nature Medicine is a part of an ongoing international effort. It also shows that the viral-entry proteins are also present in the eye and few other organs too. The mechanism of how a key entry protein is regulated with other immune system genes is predicted in the study and also potential targets for developing treatments to decrease transmission are revealed through this study.
It is known that the SARS-CoV-2, the virus that causes COVID-19 disease uses a similar mechanism to infect our cells like the
2003 SARS epidemic causing coronavirus, the exact cell types involved in the nose was not known.From more than 20 different tissues of non-infected people, the researchers analyzed multiple Human Cell Atlas (HCA) consortium datasets of single-cell RNA sequencing, to discover which cells could be involved in COVID-19 transmission. These included cells from the lung, heart, liver, kidney, gut, eye, and nasal cavity. Researchers focused on finding the individual cells that expressed both of two key Covid-19 virus entry proteins.
The first author on the paper from Wellcome Sanger Institute, Dr. Waradon Sungnak said, “We found that in cells in different organs, including the cells on the inner lining of the nose, the ACE2 receptor proteins and the TMPRSS2 protease are expressed, which can activate SARS-CoV-2 entry. Then, it was revealed that of all cells in the airways, the cells that produce mucus in the nose, the goblet cells and ciliated cells had the highest levels of both these COVID-19 virus proteins. Thus, the most likely initial infection route for the virus is through these cells.”
In the Netherlands, Dr. Martijn Nawijn, from the University Medical Center Groningen said, “These particular cells in the nose are being associated with Covid-19 for the first time now. Our findings are consistent with the rapid infection rates of the virus seen so far, though there are many factors that contribute to virus transmissibility. These cells are highly accessible to the virus and may also assist with transmission to other people due to the location of these cells on the surface of the inside of the nose.”
Also, in the cornea of the eye and in the lining of the intestine, the two key entry proteins ACE2 and TMPRSS2 were found. This revealed a potential for fecal-oral transmission and suggests another possible route of infection via the eye and tear ducts.
Various immune genes are activated when cells are fighting an infection or are damaged. This study showed probably at the same time as these other immune genes are switched in, the ACE2 receptor production in the nose is also switched on.
In the framework of the global Human Cell Atlas consortium, this work was carried out. The data is openly available to scientists worldwide and in the HCA community, more than 1,600 people across 70 countries are involved.
In order to provide further insights into the cells and targets likely to be involved in COVID-19 and to relate them to patient characteristics, the global HCA Lung Biological Network continues to analyze the data.
Director of Wellcome, Professor Sir Jeremy Farrar said, “The Human Cell Atlas is helping scientists to treat, monitor and diagnose diseases including Covid-19 in a completely new way by pinpointing the exact characteristics of every single cell type. This new research is a testament to the fact that researchers around the world are racing to deepen our understanding of Covid-19. To ensure no country is left behind and to develop effective diagnostics, treatments, and vaccines quickly, collaborating across borders and openly sharing research is crucial.”
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Coronavirus Entry Points Identified
