For example,
Human protein inherited bacteria reveals:
What if bacteria held the keys to part of our own immunity? In addition, In recent years. For example, some scientists have explored the unexpected links between the human proteins involved in the defense of the body and certain bacterial immune mechanisms. Therefore, This is the case of a team of scientists from the Institut Curie. Furthermore, the Institut Pasteur and Inserm which has just identified a protein in humans with a hitherto unknown role: Siral, derived from a bacterial domain called “Ancestral Immun”. In addition, Published in Science on July 24. For example, 2025, their work reveals a principle of biological conservation which opens up new pathways in immunotherapy by offering therapeutic targets of a new genre resulting from bacterial evolution itself.
For a long time. Therefore, scientists considered having identified in humans most of the ways of innate immunity which constitutes the human protein inherited bacteria reveals first line of defense of the organism. Furthermore, Indeed, innate immunity makes it possible to detect certain pathogens and to trigger a quick response. Similarly, Yet today, ancestral immunity, An expanding field of research calls into question this dogma. Therefore, By exploring the evolutionary links between bacterial. For example, human proteins, researchers understand that a significant number of proteins involved in innate immunity in humans derive from those present in bacteria. These proteins are not only structurally preserved: their immune role is also preserved, sometimes over billions of years.
Ancestral immunity. For example, highlighted by Siral – Human protein inherited bacteria reveals
In bacteria, the field Sir2 protein (Silent Information Regulator 2) plays a key role in defense systems Against phages, viruses that specifically infect bacteria. When a phage enters a bacteria. Sir2 triggers the degradation of an essential molecule to cellular metabolism and causes the death of the infected cell, thus protecting the rest of the human protein inherited bacteria reveals colony.
By reconstructing the evolutionary history of genes by phylogeny1a team led by Dr. Enzo Poirier. researcher at Inserm, team leader at the Curie Institute in the Immunity and Cancer Unit (Institut Curie, Inserm) and the Dr Aude Bernheimresponsible for the molecular diversity unity of microbes at the Pasteur Institute have highlighted in humans a counterpart in the SIR2 domain, named Siral and have demonstrated its role in innate immunity as well as its ability to degrade NAD, an essential molecule for cellular metabolism and energy production.
The discovery of the biological role of Siral is all the more interesting since it does not concern a single isolated protein but a diversified family of proteins which are found in 19 % of the eukaryotic genomes analyzed. divided into five large lines. These results confirm that immune mechanisms of bacterial origin are not only present. but largely preserved within the living, with potential human protein inherited bacteria reveals implications for all eucaryotes, including in humans.
In addition to the phylogenetic approach, Dr Delphine Bonhomme (E.Poirier team). Hugo Vaysset (Bernheim team) and their colleagues have shown that Siral acts as a central regulator of the TLR (Toll-Like Receptors) receptor route, a family of receptors capable of detecting typical signals of pathogens. Thus, this TLR route regulated by Siral facilitates the expression of pro-inflammatory genes and triggers the immune reaction. They have shown that without Siral. the inflammatory response is strongly altered, whether in front of a bacterial or viral infection.
“With Siral, we show that elements inherited from bacteria can play a central role in eukaryotic immune mechanisms, especially human. But more broadly. ancestral immunity gives us access to an unsuspected reservoir of immune mechanisms ”, underlines Enzo Poirier, researcher at Inserm and team leader at the Institut Curie.
“This discovery illustrates how the evolution reuses old bricks to create new human protein inherited bacteria reveals functions: mechanisms born in bacteria billions of years ago still shape our immunity today”. Specifies Aude Bernheim, head of the molecular diversity unit of microbes at the Pasteur Institute.
Human protein inherited bacteria reveals
A promising therapeutic target
Beyond evolutionary biology, the implications of the discovery of Siral are clinical. Indeed, many autoimmune pathologies depend in part on the activation of TLR receptors. Siral therefore represents an unprecedented therapeutic target, paving the way for new kind immunotherapy.
1Phylogeny designates the study of evolutionary links between species, aimed at reconstructing their relationships of kinship from a common ancestor.
Project to follow> Evocure: map the bacterial inheritances of immunity
In 2025, the Evocure project, a consortium of 5 teams led by Dr. Enzo Poirier. Dr Aude Bernheim, was selected for funding of 3 million euros over 48 months to explore the ancestral immune mechanisms common to bacteria and eucaryotes. Objective: to identify human protein inherited bacteria reveals new immune proteins, modular in therapeutics, which can open the way for innovative treatments. The Evocure project is part of the Impact Health Program launched in 2024 by INSERM and funded by France 2030.
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Reference
A Human Homolog of Sir2 Antiphage Proteins Mediates Immunity Via The Tlr Pathway. Delphine Bonhomme, Hugo Vaysset, Eirene Marie Q. Ednacot. Vasco Rodrigues, Yazan Salouum, Jean Curry, Axel Benchetrit, Pierre Alttenuati, Veronica Hernandez Trejo, Paul Vittot, Charlie Bories, Alexis Cornec, Jean-Pierre Levraud, Pedro P. Hernández, Philippe. Benaroch, Benjamin R. Morehouse, Aude Bernheim & Enzo Z. Poirier. Science, the 24 Juillet 2025.
https://doi.org/10.1126/science.adr8536
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