06/27/2021 at 10:00 CEST
North American scientists have identified an internal communication network in mammals that can regulate tissue repair and inflammation.
The discovery, the results of which are published in the journal Cell, provides new insights into how diseases such as obesity and inflammatory skin disorders develop.
As explained in a statement, the billions of organisms that live on body surfaces, such as mammalian skin, collectively called the microbiota, communicate with each other and with the host’s immune system in a sophisticated network.
The microbiota is a community of microorganisms that lives in any environment. It is found in different systems, such as the respiratory or gastrointestinal systems and defends the body from any adversity.
Related topic: Gut microbiota can predict mortality
Microbial collaborationThe immune system is a complex network of cells, tissues, and organs that combine to fight infections and other diseases.
According to the new study, viruses integrated into the host genome, remnants of previous infections called endogenous retroviruses, control how the host’s immune system and microbiota interact, affecting tissue repair and antimicrobial defenses.
Endogenous retroviruses can comprise up to 10% of all genes. The well-known role of these endogenous retroviruses, together with the scientific community’s understanding of certain diseases and inflammatory conditions, opens up new avenues of research.
‘Together, our results support the idea that mammals may have co-opted their endogenous viromes as a means of communicating with their microbiota, resulting in a multi-kingdom dialogue that controls both immunity and inflammation«Affirm the authors.
Inquiring howBased on a series of studies conducted over the past decade, showing that the microbiota extensively promotes immune protection, scientists set out to discover how this occurs.
They used Staphylococcus epidermidis, a common skin bacterium with known useful and harmful characteristics, as a study model in laboratory and mouse experiments.
The models helped them identify the important roles of skin cells called keratinocytes, as well as endogenous retroviruses, in communication between the microbiota and the skin’s immune system.
Keratinocytes are the main interface between the host and its microbiota. Their study showed that S. epidermidis triggered an antiviral response in keratinocytes.
That finding led them to discover that endogenous retroviruses coordinate responses to the microbiota that stimulate the immune system.
Fat dietThe mouse model also showed that a high-fat diet triggers an inflammatory immune response to S. epidermidis that can be controlled by providing antiretroviral treatment.
This discovery suggests a Role of endogenous retroviruses in driving inflammatory responses caused by microbes under high-fat conditions.
Researchers will continue to explore how these ancient viruses control the beneficial role of the microbiota and how nutrition can shift this dialogue toward pro-inflammatory responses.
The research was led by scientists at the NIH’s National Institute of Allergy and Infectious Diseases, the lead agency of the United States government responsible for biomedical and public health research.
Researchers from the NIH Center for Human Immunology, the National Cancer Institute, Stanford University and Scripps Research in California, the University of Pennsylvania in Philadelphia, the University of Oxford and the Francis Crick Institute also participated. In England.
ReferenceEndogenous retroviruses promote homeostatic and inflammatory responses to the microbiota. Djalma S. Lima-Junior et al. Cell, June 2021. DOI: https: //doi.org/10.1016/j.cell.2021.05.020
Top image: Credit: NHGRI