Researchers at the Center for Translational Antiviral Research at the Institute of Biomedical Sciences at Georgia State University have found that the composition of the gut microbiota affects the vulnerability of mice to respiratory viral infections and the severity of those infections. The findings, published in the journal Cell Host & Microbe, report that segmented filamentous bacteria, a type of bacteria found in the gut, can protect mice from influenza virus infection when these bacteria are naturally acquired or administered.
This protection against infection also applies to respiratory syncytial virus (RSV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. To maintain this protection, the study noted that segmented filamentous bacteria require immune cells in the lungs, called basal-resident alveolar macrophages.
Co-senior author of the study, Dr. Richard Plemper, Regents Professor and Director of the Center for Translational Antiviral Research at Georgia State University. **Georgia State University.
In this study, the researchers looked at how differences in specific microbial species affect the outcome of respiratory viral infections, and how they do this, which was not well defined before. They studied mice with discrete microbiome differences and mice with only segmented filamentous bacteria in the presence or absence of them. Viral titers in the lungs are measured a few days after infection and vary significantly depending on the nature of the microbiome of different animal groups.
These findings reveal complex interactions that mechanistically link the gut microbiota to the function of basal-resident alveolar macrophages and the severity of respiratory viral infections," said Andrew Gewirtz, PhD, co-senior author of the study and regents professor at Georgia State University's Institute of Biomedical Sciences.
The study found that in segmented filamentous bacteria-negative mice, basal-resident alveolar macrophages were rapidly depleted as respiratory viral infections progressed. However, in segmented filamentous bacteria-colonized mice, basal-resident alveolar macrophages are altered to combat influenza virus infection depletion and inflammatory signaling.
Basal-resident alveolar macrophages disable the influenza virus, in large part by activating a component of the immune system called the complement system.
What we found was noteworthy that among the thousands of different microbial species that inhabit the gut of mice, there is a common symbiotic bacterial species that has such a strong impact on respiratory viral infection models, and that this effect is largely attributed to the reprogramming of basal-resident alveolar macrophages," said Dr. Richard Plumper, co-senior author of the study. Director and Regent Professor of the Center for Translational Antiviral Research at Georgia State University. "If applied to human infection, these findings will have a significant impact on the risk assessment of patients developing severe disease in the future.
We found that segmented filamentous bacteria are highly unlikely to be the only gut microbes capable of influencing the phenotype of alveolar macrophages and are therefore susceptible to respiratory viruses," Gewirtz said. "Instead, we hypothesize that the composition of the gut microbiota broadly influences susceptibility to respiratory viral infections. Microbiota-mediated programming of basal-resident alveolar macrophages may not only influence the severity of acute respiratory viral infection, but may also be a long-term health determinant after respiratory viral infection.
Reference: "Programming of the gut microbiota by alveolar macrophages influences the severity of respiratory viral infections" by V.V. L ngo、carolin m. lieber、hae-ji kang、kaori sakamoto、michal kuczma、richard k.Plemper and Andrew TGewirtz, January 30, 2024, Cell Host and Microbes.
doi： 10.1016/j.chom.2024.01.002
The lead author of the study is Carolin M., a virologist at the Center for Translational Antiviral ResearchLieber and immunologist V.U. L. of the Institute of Biomedical Sciences at Georgia State University ngo。Other contributors were Hae-Ji Kang and Michal Kuczma of the Institute of Biomedical Sciences at Georgia State University and Kaori Sakamoto of the University of Georgia.
The study was funded by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health.
Compiled from: scitechdaily