Scientists hunting for the next antimicrobial found one that could be even more promising than they had hoped for: on the gooey backs of a newly discovered South Indian frog, they discovered a molecule that can wipe out influenza viruses while leaving cells unharmed.
The researchers were studying Hydrophylax bahuvistara , a colorful frog first described in 2015 and known for its antimicrobial secretions. After catching the amphibians, they gave them a small zap of electricity to collect some of their germ-killing mucus and then released them back into the wild, unharmed. The study was published in the journal Immunity.
The goo contained four peptides, or short chains of amino acids, that seemed to fend off viruses. Three were toxic to human red blood cells, but the fourth wasn’t. They named the peptide urumin, which comes from the word “urumi,” an Indian whip-like blade.
In the lab, the researchers tested urumin’s virus-killing abilities on mice. They first vaccinated mice with urumin and then injected them with a deadly amount of the H1 virus—also known as the swine flu. The mice survived, and after some more probing, the team discovered that the compound endowed protection by binding to hemagglutinin, a protein found on the surface of influenza viruses. Beth Mole, writing for Ars Technica, has more:
Moreover, urumin had an interesting effect on the virus: it made them explode. Usually, antiviral peptides that latch onto an HA simply block HA and keep the virus from invading cells with it, but viruses treated with urumin were destroyed. The researchers aren’t sure why, but they hypothesize that after urumin binds HA, it exerts electrostatic forces on the surface of the particle that cause the whole shell to rupture.
However it does it, “urumin represents a unique class of anti-influenza virucide,” the authors conclude, and it needs follow-up research.
Because no other antiviral peptide known to scientists has been so precise, the study authors are baffled by how the demolition process actually works.
But if researchers are able to crack the urumin secret and prove it safe in humans, it could be used as a potential therapy and help scientists embark on a vaccine that tackles all strains of influenza.
Photo credits: Sanil George and Jessica Shartouny/Immunity