▲ The process of inhibiting the SARS-CoV-2 entry factor of Staphylococcus epidermidis, a nasal symbiotic microorganism.
A study has found that Staphylococcus epidermidis, one of the symbiotic microorganisms that stay in the nose and coexist with humans, can suppress the infection of COVID-19.
A research team led by Professor Hyunjik Kim of the Department of Otolaryngology and Throatology at Seoul National University Hospital announced today (20th) that they have confirmed that Staphylococcus epidermidis, a symbiotic microorganism in the nose, reduces the expression of substances that help the corona 19 virus penetrate into the body in the nasal epithelial cells.
Corona 19 penetrates into the body by binding with ACE2 (angiotensin converting enzyme 2) and TMPRSS2 (transmembrane serine protease), which are enzyme proteins that are mainly expressed in the nose.
The Corona 19 virus uses ACE2 as a receptor to invade the cell, and TMPRSS2 helps to enter the cell by breaking down the external spike protein of the Corona 19 virus attached to ACE2.
For this reason, the penetration of the virus mainly occurs in the nasal mucosa, where these receptors and proteases are expressed.
In view of this process, the research team decided that it is important to reduce the expression of these receptors and proteases distributed in the nasal mucosa, and started the study, paying attention to the function of the nasal symbiotic microorganisms.
In the previous study, the fact that Staphylococcus epidermidis produced 'interferon', an innate immune substance when infiltrating an external virus, also served as a background to expanding the research.
Staphylococcus epidermidis is the most abundant microorganism in the nasal mucosa of normal people.
Accordingly, the research team investigated whether it was possible to suppress the COVID-19 infection after treating staphylococcus epidermis isolated from the nasal mucosa of healthy adults on separately cultured nasal epithelial cells.
As a result, it was confirmed that the expression of ACE2 and TMPRSS2, which help infiltration of Corona 19, decreased in nasal epithelial cells treated with Staphylococcus epidermis.
A correlation was also confirmed in that the more Staphylococcus epidermis was present, the decrease in their expression was also confirmed.
The research team explained, "People with a lot of Staphylococcus epidermidis in the nasal mucosa may have resistance to viral infection due to the low expression of factors that help infiltration of COVID-19."
Based on these results, the research team plans to develop therapeutic agents, such as discovering substances that inhibit respiratory viral infections such as COVID-19.
Professor Kim expected, "Using viral receptor regulation by symbiotic microorganisms in the nose, it will be possible to develop new inhaled vaccines or general-purpose therapeutics that suppress infection in the future."
The research results were recently published in the latest issue of 'iScience', an international academic journal published by Cell Press.
(Photo = provided by Seoul National University Hospital, Yonhap News)