These days, the ability of these substances to fight viruses that infect humans, including influenza and corona viruses, is being tested.
The bacterial immune system has at least one evolutionary advantage over ours – it has been fighting viruses for hundreds of millions of years. Scientists at the Weizmann Institute of Science have recently discovered a gold mine of bactericidal substances produced by bacteria, which may lead to the development of more effective drugs for viral diseases in humans. These substances are produced by antiviral enzymes called viperins; These enzymes were hitherto known only in mammals, and are now being detected in bacteria for the first time. These days, the ability of the molecules produced by bacterial wafers to fight viruses that infect humans, including influenza and corona viruses, is being tested. The study is published today in the scientific journal Nature.
Prof. Rotem Soreq and his research group in the Institute’s Department of Molecular Genetics, along with other research groups around the world, have revealed in their research over the past decade that bacteria have highly sophisticated immune systems that are specially designed to fight bacteria – bacteriophages or phages. Prof. Sorek’s group has previously discovered that some of the immune responses in bacteria have an evolutionary link to the human immune system. Their current study yields the strongest evidence to date: researchers have found that wipers – whose role in the human immune system was only understood about two years ago – also play a role in the immune system of bacteria.
Although phages are different from viruses that infect humans in their choice of targets, like other viruses they are made up of a genetic material – DNA or RNA – and they spread themselves by invading a host and taking over its cellular replication machines. In humans, viperin is part of the innate immune system, the earliest part of the evolutionary immune system, and is produced when a signaling substance called interferon alerts the immune system to the presence of pathogenic viruses. Once produced, the wafarin releases a unique molecule, capable of acting against a wide range of viruses according to one simple rule: the molecule “mimics” nucleotides – the pieces of genetic material needed to replicate the genome. But the viperine molecule is fake: it lacks a vital link, allowing the next nucleotide to be attached in line to an ever-expanding strand. Once these fake nucleotides are inserted into the replicating viral genome, replication stops – and with it the virus.
The simplicity of the mechanism and the breadth of its action against many different viruses, may imply that the vipers have been with us for a long time, but could it be that they are as ancient as the ancestor common to us and the bacteria? Led by Dr. Ode Bernheim, who was a postdoctoral researcher in Prof. Sorek’s group, team members applied methods developed in their laboratory to locate bacterial sequences that encode possible vipers. “While the human vaporin produces only one type of antiviral molecule, the bacteria produce a surprising variety of molecules, each of which may serve as a new antiviral drug,” says Prof. Sorek.
Based on the genetic sequences, Prof. Sorek and the research team were able to trace the evolutionary history of the viperins. “We have discovered that this important component of our antiviral immune system originates in the bacterial defense system,” says Prof. Soreq.
If bacterial vipers are found to be effective against human viruses, Prof. Sorek believes this could pave the way for the discovery of additional molecules produced by bacterial immune systems, and their adoption as antiviral drugs for human disease. “As was the case decades ago with antibiotics – antibacterial substances first discovered in fungi and bacteria – we may learn how to identify and adopt the antiviral strategies of organisms that have been fighting infections for hundreds of millions of years.”
The current study was conducted in collaboration with researchers from Pantheon Biosciences, which has been licensed by the Knowledge Company, the intellectual property commercialization arm of the Weizmann Institute of Science, to develop antiviral drugs based on the findings. Further research is currently underway to find out which of the bacterial wafers may be best suited for the fight against human viruses, including influenza and corona viruses.
Adi Milman, Gal Ofir, Gilad Meitav, Carmel Avraham, Sara Melamed and Dr. Gil Amitai also participated in the study.
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