Tiny frogs create unique peptide to fight bacteria, study finds
Findings have implications not only for fighting bacteria, but to create a coating that can prevent implants and medical devices from triggering an immune response.
By AARON REICHBibron's toadlet sits an a finger as conservation efforts continue following last summer's bushfire on Kangaroo Island, Australia December 2, 2020 in this image obtained from social media. Picture taken December 2, 2020.(photo credit: KANGAROO ISLAND LAND FOR WILDLIFE/ASHLEE BENC VIA REUTERS)
A peptide found in Australian toadlets has been found to have remarkable properties that help it fight bacteria, according to a new scientific study.Conducted in collaboration between researchers from Technion-Israel Institute of Technology in Haifa and the European Molecular Biology Laboratory (EMBL) in Hamburg, the study focused on solving a 3D molecular structure of the specific peptide.Dubbed uperin 3.5, the peptide is found in Uperoleia mjobergii, also known as Mjoberg's toadlet, a small relative of toads found in Australia. The amphibian generates the peptide as part of its immune system and secrets it into its skin.According to the scientists, however, the peptide essentially constructs itself into a unique fibrous structure, changing its form when necessary to protect the toadlet from bacterial infections. In other words, these peptides regulate and reshape themselves on a microscopic level to combat bacteria.What is even more notable about these antibacterial fibrils is that their structure is very similar to amyloid fibrils. This is significant, because these were until recently considered almost exclusively the signs of diseases, and are in fact a defining hallmark of many neurodegenerative diseases like Parkinson's and Alzheimer's.However, recent studies have found that certain amyloid fibrils are shown to benefit the organisms that produce them, with some microbial bacteria being known to use them to protect themselves from the human immune system.Essentially, the toad's peptides work in the same way, self-assembling into amyloid fibrils that act as a reserve of defensive means against bacteria. This form, which scientists called a cross-β conformation, shifts into a less compact cross-α form in the presence of bacteria, becoming an antibacterial weapon.“This is a sophisticated protective mechanism of the toadlet, induced by the attacking bacteria themselves,” the study's lead author, structural biologist Prof. Meytal Landau, said in a statement.“This is a unique example of an evolutionary design of switchable supramolecular structures to control activity.”The findings hold significant implications for humans, as not only could they help find means of combatting bacteria or even cancer cells - as they have been noted to do on occasion in nature - but also shedding light on potential properties of amyloid fibrils in neurodegenerative conditions.This would include the developments of synthetic antimicrobial peptides, which could help protect the body from bacteria, or could be used as a coating for implants and medical devices to prevent triggering an immune response. This is important, considering how an immune response to implants or transfers can complicate many important medical procedures.Many means of treating neurodegenerative diseases suffer from this problem, as certain immune responses and anatomical obstacles like the blood-brain barrier prevent medically-induced therapeutic agents into the brain.As a result, finding means of bypassing the barrier "has been somewhat of a holy grail in the field," according to Jeff Karp of the Brigham's Department of Anesthesiology, Perioperative and Pain Medicine, who had helped research one such potential method of doing so back in December.One other effort to bypass the barrier was developed in 2020 by scientists at Technion, which was adapted by Nextage Theraputics as a means of allowing cannabis molecules to cross into the brain.
