Bacteria in the gut may be able to boss around the genes found in their hosts – at least, in worms. According to a new study published in the journal Cell, trillions of bacteria found within the average gut may be practicing a sort of "interspecies communication" that transcends language.
Gut bacteria secrete a molecule called nitric oxide. In an attempt to understand how bacteria communicate with its host, researchers tracked nitric oxide levels inside tiny worms (C. elegans). They found that this molecule is capable of attaching to thousands of host proteins and, as such, changed the worm's ability to regulate its own gene expression. And if it works in worms, there is a possibility similar activity could be happening within our own stomachs. Previous research has shown that nitric oxide attaches to human proteins in a process known as S-nitrosylation, which has been linked to diseases like Alzheimer's, Parkinson's, asthma, and cancer, among others.
"There is tremendous complexity in the gut, and many researchers are after the next unusual substance produced by a bacterium that might affect human health. The enormity of the gut bacteria population and its relationship to the host predicts there will be general means to communicate that we humans can recognize,” said study author Jonathan Stamler in a statement.
In the lab, researchers fed growing worms bacteria that naturally produce nitric oxide and then selected a specific protein called argonaute protein, or ALG-1. When nitric oxide was secreted by the bacteria and attached to ALG-1, the worms developed malformed reproductive organs and died. Too much nitric oxide took control of the worms' DNA silencing proteins and impaired any hope of healthy development.
"Our findings suggest a general mechanism by which the microbiota may control host cellular functions, as well as a new role for gasotransmitters," wrote the authors.
However, such dire outcomes are likely not present in most animals. Stamler notes that mammals outside of the lab are probably able to adjust and accommodate to changing nitric oxide levels in real time.
“The worm is going to be able to stop eating the bacteria that make the nitric oxide, or it will begin to eat different bacteria that makes less nitric oxide, or change its environment, or countless other adaptations. But by the same token, too much nitric oxide produced by our microbiome may cause disease or developmental problems in the fetus," he explained.
Stamer says his research adds to a growing body of work that shows how bacteria living in the gut influence diet and environment, thus impacting our health tremendously. He hopes his work has future therapeutic potential.