Frog Peptides & Inhibiting Viruses

The Secrets of Nature: The Frog Prince and Inhibiting Viruses

Prior to the invention of the first home refrigeration systems families across the world had to find alternative ways to keep their perishables, like milk, from spoiling. Some people built ‘cool pantries’ along the north facing walls of their cottages, while others dug deep cellars under their houses. But perhaps one of the most unconventional methods was conceived by the Russians and the Finnish, who found that placing the Russian Brown Frogs in their milk prevented it from spoiling. While this practice may sound preposterous and unpalatable, it did reveal that different species of frogs secrete unique peptide combinations through their skin which protect the frog from infection by killing off threatening bacteria or viruses.

The antimicrobial peptides found in frog skin secretions inspired Emory researchers: Joshy Jacob, Song Hee Lee, and David Holthausen to ascertain if the peptides found in other frog species secretions could be used as antimicrobials. “We came to understand that frog-skin is like a pharmacy. Essentially we wanted to know if there is a frog that produces cross reactive peptides that can neutralize particular viruses.” said Jacob, associate professor in microbiology and immunology.

David Holthausen, Joshy Jacob, Song Hee Lee
Jacob Group Photo

They found their answer in the Southern Indian state of Kerala, where their research collaborators found their golden goose or rather golden frogs (Hydrophylax bahuvistara). The research team from the Rajiv Ghandi Centre for Biotechnology in India electro-stimulated the frogs, causing them to secrete a clear solution of antimicrobial peptides, which were sequenced. Using the sequenced peptide, Emory researchers recreated the frog peptide library in the lab. They then tested these peptides on microlayers of cells infected with the influenza virus to determine if the peptides could inhibit viral replication. The peptides secreted by Hydrophylax bahuvistarawereidentified to inhibit influenza virion replication in vitro. Jacob dubbed the peptide sequence Urumin, after a whip-like sword developed by fighters from the same region of India as the golden frog itself.

Hydrophylax bahuvistara Frog
Frog Photo

The Emory team has now successfully tested the use of Urumin in treating influenza in mice and is now in the stages of learning to stabilize and deliver the peptide sequence for medicinal use in humans. Justin Burns, a licensing associate at Emory Office of Technology Transfer, said, “There is still a long journey to the dissemination of Urumin as a clinical therapeutic. However, Urumin and other frog skin peptides hold great promise as future treatments for multiple viruses, including influenza and even Zika.” In fact, Emory researchers have already found a unique peptide sequence from another frog that successfully inhibits both Zika and Dengue viruses in vitro. Maybe like the story of the frog prince, if we can only look past their slimy, green exterior, we can unlock a wealth of antimicrobial peptides, which may serve to change the face of medicine.

Techids: 16134, 17057

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