Caused by a viral protein called papain-like protease (PLpro)
Posted on 01.24.2024 10.10pm Posted on 01.24.2024 10.10pm Modified on 01.24.2024 4.57pm Views 90
Sneezing protects the body by expelling annoying and potentially harmful substances from the body. [사진=게티이미지뱅크]A new study has revealed the mechanism by which the COVID-19 virus (SARS-CoV-2) causes people to sneeze. This is what the scientific journal Science reported on the 23rd (local time) based on an article by researchers from the University of California, Berkeley (UC Berkeley) published on the biology thesis preprint site BioRxiv.
The researchers found that one of the virus’ proteins stimulates neurons in the respiratory tract, triggering the sneezing reflex. This is expected to help discover new treatments to relieve COVID-19 symptoms and reduce transmission of SARS-CoV-2. This may also apply to other viruses that cause sneezing.
Professor Isaac Chiu (neuroimmunology) of Harvard University Medical School, who reviewed the paper, pointed out: “Until now nothing was known about how viruses cause sneezing.” This study is said to be the first to demonstrate that viral proteins “can be detected directly by the nerve cells that trigger sneezing.”
Sneezing protects the body by expelling annoying and potentially harmful substances from the body. At the same time, it helps pathogens like SARS-CoV-2 reach new hosts. A person’s sneeze sprays 40,000 virus-filled droplets up to a distance of 8 meters. But scientists hypothesized that sneezing was just a byproduct of the disease because infected cells release molecules that irritate the nasal passages.
Researchers led by Diana Bautista, a professor of neurophysiology at UC Berkeley, suspected that SARS-CoV-2 might play a more direct role. Infected cells release large amounts of a viral protein called papain-like protease (PLpro), a type of enzyme called a protease that breaks down other proteins. Previous research has shown that other proteases produced by plants, bacteria and even humans stimulate sensory neurons that induce sneezing.
The researchers sprayed PLpro into the noses of mice and found that it stimulated a subpopulation of sensory neurons called nociceptors that trigger pain and itching. The researchers then tested PLpro’s effectiveness on sneezing. The rats began sneezing about 14 seconds after exposure to PLpro. Those who ingested the control mixture began sneezing about 30 seconds later. Mice given PLpro sneezed nearly four times more than controls in the first two minutes, the researchers reported.
Professor Bautista said he was “both excited and scared” because the results showed the powerful effect of sneezing in promoting viral transmission. By injecting a test solution dyed with blue dye into the noses of mice and measuring the spots on the bottom of their cages, the researchers showed that sneezing causes the expulsion of large amounts of nasal secretions.
The researchers were unable to test whether PLpro increased coughing, another symptom of the virus spreading. This is because it was difficult to determine whether the mouse was coughing. Instead, we found that PLpro was associated with facial and mouth pain, which is common in COVID-19. When the protein was injected into the cheeks of rodents, the animals wiped their faces more often with their front paws, which was interpreted as a sign that those areas were sore.
The researchers tested two different coronaviruses and found that PLpro from the coronavirus that causes severe acute respiratory syndrome (SARS) also stimulates sensory neurons. The researchers found that some viruses that cause respiratory illnesses, such as influenza, also appear to cause loud sneezing because they carry PLpro.
PLpro activates nociceptors by inducing protein channels to accept calcium, but does not act directly on the process. The researchers hypothesized that PLpro targets other receptors that they have not yet identified.
Professor Theodore Price (neurophysiology) of the University of Texas, USA, who reviewed the study, said this finding was “very powerful”. Because PLpro is necessary for SARS-CoV-2 to infect cells, studies are already underway to explore it as a drug target. Dozens of compounds that can block PLpro are in preclinical development.
The new findings suggest that these candidates may help soothe symptoms and block transmission. However, Professor Felipe Ribeiro, a neuroimmunologist at Washington University School of Medicine in St. Louis (WUSTL), warned that the possibility that sneezing accelerates recovery from COVID-19 should be ruled out. He emphasized the cautious approach, saying that it has not yet been proven that “blocking sneezes is not harmful.”
The document can be found at the following link:
“Copyright ⓒ ‘Honest Knowledge for Health’ Comedy.com ( / Unauthorized reproduction and redistribution prohibited”
2024-01-24 13:11:00
#sneeze #COVID19