This happens in the body when we are exposed to stress

Stress hormones trigger numerous reactions in the organism

Scientists at the Max Planck Institute for Molecular Genetics (MPIMG) are investigating the reactions in the body that are triggered by the release of stress hormones. Typical stress reactions include increased heart rate, accelerated breathing, and rising blood pressure. The researchers report how stress hormones are released into the bloodstream and transported to the various tissue and cell types in the body. Ultimately, the entire body is at the mercy of these hormones.

Although the whole organism is confronted with the same stress hormones, cells react with different physiological measures. For example, fat cells mobilize energy reserves and immune system cells shut down their activity. Why the cells react so differently to stress has so far been largely unclear. Sebastiaan Meijsing and his team have now discovered in their research a so-called enhancer, which has a regulatory function and can influence the activity of genes.

Scientists at the Max Planck Institute for Molecular Genetics are discovering new mechanisms for how the body reacts to stress. (Image: alphaspirit / fotolia.com)

How do the cells react to stress signals??

The MPIMG research team examined in particular the so-called enhancers. These are specific regions in the genome that have a regulatory function and can influence the activity of genes. The scientists discovered that a single enhancer in different cell types can regulate different stress responses.

The same enhancers can cause different reactions

To further investigate the function of the enhancers, the research team removed the enhancers from the lung cell genome. Next, they examined how the behavior of cells changes when exposed to stress hormones. These studies have identified several enhancers responsible for the stress-related changes. Afterwards, the scientists examined the activity of the same enhancers in bone cells and surprisingly found that the same enhancers trigger different reactions. Thus, in the lung cells, a DNA segment (transcript) was activated, which has a long distance to the enhancer. In contrast, the same enhancers in bone cells activated a transcript in close proximity.

Toaster or kettle?

In a press release from the Max Planck Institute in Berlin, Sebastiaan Meijsing tries to make the research results understandable even to non-experts: "Imagine that you only have a socket with which you can either use your toaster or your kettle," Meijsing says. Both would work, but you have to decide for a device. So similar was the situation in these two cell types. The investigated enhancer could activate either the adjacent or the more distant DNA segment.

How does the enhancer decide which section will be activated??

"For the region we studied there is evidence that folding the genome in the bone cells allows the enhancer to interact with the adjacent DNA region," explains Meijsing. In contrast, in the lung cells, the genome is folded so that the enhancer can only interact with the more distant portion of the DNA. Such "reuse" of existing enhancers for various genes allows the organism to generate different products in response to stress.

The three-dimensional folding of the genome

In the formation of different cell types, there are different three-dimensional folds of the genome. These differences allow for various interactions between enhancers and the genes or transcripts. According to Meijsing, this differential use of the same enhancers in different cell types can contribute to the diverse physiological stress reactions in the human body.

Coping with stress

Many forms of stress can negatively affect health. Especially people who are exposed to frequent and prolonged stress both professionally and privately should learn how to deal with it. For this purpose, various exercises and measures to reduce stress are available. Proven relaxation techniques include:

• Autogenic training,
• Progressive muscle relaxation,
• yoga,
• and meditation.

(Vb)