A drug, commonly used for the treatment of asthma and allergies, can also block an important protein that is necessary for the replication of SARS-CoV-2, scientists at the Indian Institute of Science (IISc) have found. The findings of this crucial study have been published in the journal eLife.
The drug, montelukast, is consumed orally to prevent wheezing, breathing difficulty, chest tightness, and coughing caused by asthma. According to the US National Library of Medicine, it is also used to prevent breathing difficulties during exercise.
“Montelukast is prescribed in India by physicians. It is readily available as tablets and syrup (for kids) in pharmacy shops under different brand names,” IISc Assistant Professor Tanweer Hussain, senior author of the study, told The Indian Express.
Hussain also said that some clinicians were using montelukast to treat COVID-19 patients because of its known role in making breathing easier in asthma patients. He also informed that it was not known that this drug also has antiviral activity, which we have figured out in this study.
According to the researchers, when the COVID-19 virus infects the human cell, it releases a protein called Nsp1, which is essential for its replication. Then, the protein sticks to the host cell’s ribosome.
If this protein, Nsp1, is targetted, then the damage caused by the virus can be reduced. Moreover, the researchers found that montelukast binds strongly to Nsp1, and blocks its access to the ribosome. The scientists also informed that Nsp1’s mutation rate is very low as compared to other viral proteins. This means Nsp1 is likely to remain largely unchanged in any virus variants that emerge. Consequently, drugs targeting this region are expected to work against all such variants.
The scientists first used computational modelling to screen more than 1,600 drugs approved by the US Food and Drug Administration (FDA). Then they shortlisted a dozen drugs that bind to Nsp1, among which they zeroed in on montelukast and saquinavir which is an anti-HIV drug. However, lab tests on cultured human cells found that only montelukast was able to rescue Nsp1’s inhibition of protein synthesis.