Gut bacterial molecule reduces intestinal inflammation by slowing cell energy

Enterobactin, a molecule produced by gut bacteria, may hold a surprising key to reducing intestinal inflammation. Not by attacking the immune system directly, but by temporarily slowing down the cell's own energy production.

That is the finding of a new study from Dr. Matam Vijay-Kumar, a professor in the University of Toledo College of Medicine and Life Sciences, published in the Gut Microbes peer-reviewed journal. The research builds on more than a decade of work from Vijay-Kumar's lab on enterobactin, a molecule secreted by certain gut bacteria including E. coli, whose primary job in nature is to scavenge iron from the surrounding environment.

We are working on this enterobactin for more than 10 years. There are a lot of studies which suggest that we can exploit the microbial metabolites for our benefit, and this could be one among them."

Dr. Matam Vijay-Kumar, Professor, University of Toledo College of Medicine and Life Sciences

The study's central finding involves mitochondria, the cell's energy-producing structures, responsible for generating ATP, the energy that powers virtually every cellular function. Vijay-Kumar's team discovered that enterobactin, because it is fat-soluble and can penetrate cell membranes, is able to enter the mitochondria and bind to the iron that curtails their energy-producing process. The result is a measurable reduction in mitochondrial respiration. In other words, the cell's power output is temporarily dialed down.

In healthy cells, that would be undesirable. But in inflamed intestinal tissue, it could be viewed as a positive outcome.

"While reducing energy might sound harmful, it can actually be beneficial in inflamed tissues. In conditions like intestinal inflammation, high energy activity can worsen damage," Vijay-Kumar said. "By gently lowering this activity, enterobactin may help reduce inflammation and protect the tissue."

This concept connects to an emerging area of biomedical research called mitohormesis; the idea that a low-grade stress applied to mitochondria can actually increase cell survival and resilience. Vijay-Kumar draws a comparison to metformin, one of the most widely used diabetes medications in the world, which works through a similar mechanism of mild inhibition of mitochondrial respiration.

The first author of the publication, Dr. Vinita Kushwaha, also tested 2, 3 dihydroxy benzoic acid (2,3-DHBA), a breakdown product of enterobactin. To understand its effects, the team tested this compound in mice with colitis, a condition that causes inflammation in the intestine and is similar to inflammatory bowel disease in humans. The results were encouraging. Mice treated with 2,3-DHBA showed significantly less inflammation, a stronger and healthier gut lining, which helps prevent harmful substances from leaking into the body, and better healing of damaged tissue compared to untreated mice.

The researchers believe that this smaller molecule works by "reprogramming" how cells produce energy. It gently adjusts the activity of mitochondria, the parts of the cell responsible for energy production so that cells in inflamed tissues do not overwork themselves. This helps reduce damage and calms inflammation.

The findings also connect to Vijay-Kumar's broader body of research on how enterobactin interacts with the immune system. Earlier published work from his lab, including a paper titled Enterobactin Hijacks Neutrophil Function, demonstrated that the molecule can inhibit neutrophils, the white blood cells that serve as the immune system's first responders to inflammation, infection and injury.

Vijay-Kumar said his lab is pursuing additional funding to continue investigating how enterobactin's effects on mitochondrial function might be harnessed therapeutically, and whether existing IBD medications may already be generating similar compounds as part of their mechanism of action.