Molecular biologists from the Liaoning Institute for Cancer Research (China) have discovered another receptor involved in the development of coronavirus infection.
As you know, the SARS-CoV-2 virus enters the human body through the ACE2 receptor, which covers the surface of the mucous membrane of the lungs and some other organs. But is ACE2 the only Trojan horse that drives the coronavirus into the human body?
Scientists, studying the structure of the S-protein of the coronavirus, drew attention to the fact that only part of this protein envelope is involved in the attachment of the virus to the receptor. What are the functions of the rest of the chain?
By comparing the structure of this molecule with the structure of other human cellular receptors, biologists found that the S-protein contains amino acid sequences very similar to those responsible for the connection of the SRB1 receptor with cholesterol and lipoprotein molecules, according to the scientific journal Nature Metabolism. They found that the virus can combine with cholesterol.
They then added large amounts of cholesterol and lipoproteins to the cell culture medium and tested if they could be infected with SARS-CoV-2.
The experiment confirmed that the more cholesterol molecules were in the culture medium, the faster the virus spread. This proved the role of cholesterol and receptors recognizing it in the process of virus penetration into healthy cells.
When biologists used a drug that blocks receptors, the virus slowed down.
Thanks to molecular engineering, scientists were able to explain why the course of the disease in patients with coronaviruses varies so much, why some get sick very seriously, others very easily or do not get infected at all. It depends on whether there are functional ACE2 molecules on the surface of the cell walls. It is with their help that the interaction of the S-protein of the virus with the SRB1 receptors leads to infection.
For the same reason, many drugs for viral hepatitis C act on the coronavirus: its virus also uses the SRB1 receptor as the main transmission channel. "Drugs that block the ACE2 receptor make it easier to carry the coronavirus infection," the scientists said.
The value of the study is that by acting on this feature of the virus, drugs can be created to suppress and treat coronavirus infection.