By boosting a protein called oligoadenylate synthetases-like (OASL) that naturally exists in our cells, researchers may have found a way to enhance our ability to inhibit viral infections like the flu.
OASL appears in increased quantities in people with liver cancer caused by the hepatitis C virus.
Hepatitis C, influenza, the childhood respiratory illness RSV, and many other viruses are known as ribonucleic acid (RNA) viruses, which use RNA as their genetic material when they replicate. The OASL protein enhances cells' ability to detect virus RNA, activating the immune system to sense the virus and inhibit replication.
In laboratory tests, boosting this protein in human cells effectively inhibits viral replication. Conversely, mice that do not have OASL were found to be much more susceptible to viral infections.
The finding is especially notable because it may offer an alternative to interferons, another kind of protein that is made and released by cells in response to viruses. Interferons are used in therapy against some viral infections, including hepatitis C, but are not effective for other RNA viruses, such as influenza. Interferon therapy also has major side effects, and not all patients respond well to treatment.
"Despite remarkable advances in vaccination and treatment, diseases caused by viral infections remain among the leading causes of death worldwide," said senior author Saumendra N. Sarkar, Ph.D., assistant professor of microbiology and molecular genetics at the University of Pittsburgh. "We need new defenses against viral infections, and our discovery is proving to be a promising avenue for further exploration."
Sarkar and colleagues plan to determine the most efficient way to boost the OASL pathway in patients and are working with pulmonologists to develop and identify funding for a study to evaluate the effect of boosting OASL in people with lung infections.
"The respiratory system is a much easier target to deliver this type of therapy, compared to an organ, such as the liver, so we'll be starting with infections like RSV," said Sarkar. "From there we could branch out to other RNA viruses and perhaps find effective ways to boost our inherent immunity against a broad range of viral infections."