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Compiled by Zakiyah Ebrahim
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Health24
26 Oct 2020, 04:45
- Scientists already know that SARS-CoV-2 uses the ACE2 receptor to infect human cells.
- However, a new advance explains how the virus uses a receptor called neuropilin-1 to infect human cells.
- This receptor is widespread in many human tissues.
As the number of confirmed global SARS-CoV-2 infections approaches 1.7 million, scientists are still struggling to understand what makes the virus so effective and transmissible.
But a new study may have the answer: The virus is using a second protein, called neuropilin-1, to facilitate entry into human cells.
The first receptor, angiotensin-converting enzyme 2 (ACE2), was discovered during the early stages of the pandemic, and scientists came to understand how the virus used it to bind to the surface of cells. An enzyme called transmembrane serine protease type II (TMPRSS2) was also found to be crucial for gaining entry.
The findings of the researchers, from the Technical University of Munich in Germany and the University of Helsinki in Finland, were published in Sciences.
“To effectively infect human cells, SARS-CoV-2, the virus that causes Covid-19, can use a receptor called neuropilin-1, which is very abundant in many human tissues, including the respiratory tract, blood vessels and neurons. “stated a press release from the University of Helsinki.
Comparing viral genomes
“The starting point of our study was the question of why SARS-CoV, a coronavirus that caused a much smaller outbreak in 2003, and SARS-CoV-2, spread so differently even if they use the same main ACE2 receptor, “said University of Helsinki virologist Ravi Ojha.
Part of what led to the researchers’ discovery was comparing the two viral genomes – the virus’s hereditary information – and analyzing the viral surface proteins, the “spikes,” that anchor the virus to cells.
What they found was that SARS-CoV-2 had picked up sequences responsible for producing a series of spiny hooks to latch onto host tissues, which was not used by other pathogens.
“Compared to its older relative, the new coronavirus had acquired an ‘extra piece’ in its surface proteins, which is also found in the spikes of many devastating human viruses, including Ebola, HIV, and highly pathogenic strains of avian influenza. , among others, “said Olli Vapalahti, a virologist at the University of Helsinki.
After working together with colleagues from around the world, the team turned their attention to neuropilin-1.
Main function of neuropilin-1
Normally, as a cell surface receptor, neuropilin-1 plays a role in the response to important growth factors in tissue development. However, it can also act as a convenient control for viruses by allowing them to adhere to host cells long enough to penetrate.
The researchers used electron microscopy, monoclonal antibodies, examined receptor-expressing tissue samples taken from deceased Covid-19 patients, and conducted an experiment with mice to confirm their suspicions of its role in facilitating the entry of SARS-CoV-2 into the disease. nervous system.
“If you think of ACE2 as a door lock to enter the cell, then neuropilin-1 could be a factor that directs the virus towards the door,” explained Giuseppe Balistreri, virologist at the Faculty of Biological and Environmental Sciences of the Helsinki University.
“ACE2 is expressed at very low levels in most cells. Therefore, it is not easy for the virus to find doors to enter. Other factors such as neuropilin-1 could help the virus to find its door.”
Since neuropilin-1 is expressed in large amounts in the nervous tissues within the nasal cavity, it means that the new coronavirus has a convenient advantage in infecting human cells.
“Currently, our laboratory is testing the effect of new molecules that we have specifically designed to interrupt the connection between the virus and neuropilin,” said Balistreri.
“The preliminary results are very promising and we hope to obtain in vivo validations (research carried out within a living organism) in the near future.”
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Image: Getty / Fiordaliso
