When it comes to fighting off pathogens like Listeria, your best allies may be the billions of microorganisms that line your gut, according to new research published in mBio, the online open-access journal of the American Society for Microbiology. The study reveals that germ-free mice are more susceptible to infection with the foodborne pathogen Listeria monocytogenes than mice with conventional intestinal microbiota.
The authors were also able to show that expression of five intestinal microRNA (miRNA) molecules decreases in conventional mice upon Listeria infection while it did not in germ-free mice, indicating that the gut microbiota may determine, at least in part, how the mouse genome expression is reprogrammed in the gut and how the animal responds to an infection.
"We were surprised by the robustness of the intestinal miRNA signature in germ-free mice and conventional mice," says corresponding author Pascale Cossart of the Institut Pasteur in Paris, France. "Our results show that even very small variations in miRNA expression can have important outcomes," for the health of the animals, says Cossart.
In recent years, researchers have come to recognize that the gut microbiota is an indispensable partner in the development of an animal's immune response and in maintaining its internal stability, but few studies have addressed the impact the microbiota has on miRNA expression during bacterial infections. Cossart and her colleagues approached the matter using the system they know best: Listeria infection. L. monocytogenes is a frequent contaminant of raw milk products, and a highly publicized outbreak traced to Listeria-contaminated cantaloupe left 30 people dead in the fall of 2011.
Previous studies in Cossart's lab have shown that during infection with Listeria, the bacterium AND the host both reprogram their protein manufacturing using small non-coding RNA mole
|Contact: Jim Sliwa|
American Society for Microbiology