How the microorganisms in the gut 'hack' control your genome

Research can develop to explain why eating a lot of fiber helps to reduce colon cancer.

You already know that, in your intestinal tract, there is now a diversity of microorganisms. They don't just sit there and wait for your next meal. A new study shows these may affect our genes.

Accordingly, a chemical is produced by bacteria in the digestive system, which affects chromosomes in neighboring cells. This discovery may help us better understand the link between diet and the development of one of the most dangerous cancers in the world.

The study was conducted by Babraham Institute in England. In it, scientists discovered DNA in the intestinal epithelium in humans containing an unusually high chemical concentration. This chemical has been known to act as a epigenetic switch that can turn genes on and off.

The gut microbes can rob the control of your genome.

The process of turning off epigenetic genes, involves many problems, from genetics, to aging to cancer. In addition, high levels of this chemical are also recorded in another part of the body: the brain.

Crotonylation is a new genetic modification pathway recently discovered by scientists. Like methylation, crotonylation changes the way genes are expressed by refining the chemical environment without making real changes in the genetic code.

While methylation will add a methyl group (CH ₃ ) to a base nucleotide - usually cytosine (C), but occasionally adenosine (A) - crotonylation binds an acetyl (-COCH ₃ ) group to proteins. called histones, which help wrap neat DNA strands.

It is possible to imagine histone as a core, allowing DNA strands to be compacted into a pinch, pinching to form the chromatin strands. Crotonylation occurs that can 'turn on' a certain gene, manifesting outside a creature's trait.

In the process of searching for acetylated histones, the scientists found that an agent is preventing the body from removing acetyl groups from DNA in the opposite process of crotonylation. They suspect that the agent is actually small organic molecules, called short-chain fatty acids (SCFA) . They are produced when intestinal bacteria ferment fiber in foods such as vegetables and fruits.

Previous research has suggested a link between cellular metabolism and acetylation, indicating that SCFAs are the triggers. Through analysis of tissues in a variety of organs such as the colon, brain, liver, spleen and kidneys, scientists found that high levels of acetylation occur only in the brain and colon.

Crotonylation affects histones through which an expression gene can be turned on.

Why is this process only happening in the brain, not other bodies that are still mysterious? However, this new study shows that bacteria have the ultimate responsibility for gene expression in the intestinal tract.

"Short-chain fatty acids are a key source of energy for cells in the intestinal tract, but we have also shown they affect the crotonylation of genes ," said the study's lead author, Rachel Fellows from Babraham Institute.

Specifically, SCFA produced by bacteria found in healthy human intestines promotes acetylation by preventing an enzyme called histone deacetylase 2 (HDAC2) from removing these acetyl groups.

To confirm that the bacterium is indeed the agent that promotes crotonylation, the researchers gave mice an antibiotic to kill most of their intestinal bacteria. As a result, SCFA levels have decreased, while the crotonylation of intestinal histones has also decreased.

If bacteria survive in the intestinal tract and promote crotonylation, what benefits can humans get? That's what scientists aren't sure about.

However, this study suggests a link between diet that affects our genes. For example, it may explain why eating a lot of fiber helps to reduce colon cancer.

Research can develop to explain why eating a lot of fiber helps to reduce colon cancer.

With about 770,000 colon cancer deaths each year, finding ways to prevent and treat the disease is also a high priority for scientists.

Meanwhile, for the average person, this study is a good reminder for us to check our diet, ensuring that it is not only good for the body but also good for the microbiota. gut.

"Our intestines are home to countless bacteria that help digest food like plant fiber," said Patrick Varga-Weisz, one of the study authors.

"They also act as a barrier to harmful bacteria and our immune system education. How these bacteria affect our cells is key to processes. this ".

This research was published in Nature Communications.