Work with a mouse model of inflammatory bowel disease found that introducing microcin, a protein with antimicrobial properties, into the mice worked to reduce inflammatory responses in the gut.
The study, “Microcins mediate competition among Enterobacteriaceae in the inflamed gut,” published in the journal Nature, may also have implications for a wide range of inflammation-mediated conditions, from autoimmune diseases like Crohn’s disease and colitis to certain bacterial infections.
Researchers at the University of California, Irvine, took mice with induced inflammatory bowel disease (IBD) and treated some with doses of an E. coli bacteria that produces microcin, while others received other E. Coli doses, including harmful ones. Microcins are produced and secreted by certain probiotic bacteria, a bacteria believed to work by keeping in check other bacteria not usually found in the gut or that is multiplying too rapidly.
An analysis of inflammation levels, using known markers, found that mice treated with the protein showed a less severe inflammatory reaction than the control mice, indicating that the microcin was able to overcome harmful bacteria.
Specifically, the research team, led by Martina Sassone-Corsi, divided the IBD mice into four treatment groups: those given microcin-producing E.coli bacteria, those given E.coli that can’t secrete microcins, another given an E.coli strain implicated in Crohn’s disease, and a group given diarrhea-producing Salmonella enteric. Mice that received microcin-secreting E.coli were better able to colonize and replace the harmful gut bacteria and, subsequently, had less inflamed guts.
The researchers believe that microcins alter interactions within the mice’s gut microbiota, and, potentially, these molecules may have the same effect in humans.
“Our work provides the first evidence that microcins mediate inter- and intra-species competition among the Enterobacteriaceae in the inflamed gut. Moreover, we show that microcins can be narrow-spectrum therapeutics to inhibit enteric pathogens and reduce enterobacterial blooms,” they reported in a study abstract included in a press release.
Even though the concept of using bacteria in combination with standard treatments has been of interest to scientists, the exact mechanisms governing bacterial interactions in the gut are not yet clear. As such, attempts on using bacteria for therapy are limited.
These results may help to change that by reporting in favor of microcin-producing bacteria to augment current IBD treatments.