Environment imperceptibly creates the risk of diseases

A person is constantly affected by “exposure”, that is, the totality of all external influences over a lifetime, from polluted air and food components to medicines and household substances. It is estimated that environmental pollution is associated with about one in six deaths worldwide. It was extremely difficult to establish clear links between specific substances and diseases.

The fact is that structurally similar molecules can act in completely different ways, and completely dissimilar substances can cause the same disorders. Traditional approaches based on chemical structure classification do not explain what is really happening in the body.

The team collected data on almost 10,000 different exposures and tracked how each of them affects the functioning of human genes. This resulted in a large network, where the nodes represent individual substances and the connections between them reflect the similarity of their biological effects.

When the scientists analyzed this network, they discovered distinct clusters. The substances were grouped not by their appearance, but by the systems of the body they affect. In some clusters, there were compounds that affect inflammation, in others, that affect metabolism, blood clotting, etc. It turned out that pharmaceutical drugs and industrial toxins, not related in any way by structure, can affect the same molecular pathways.

To understand why some effects are more harmful, experts compared the effects of substances with a map of protein interactions in the cell. This network contains key proteins that control many important processes. The study found that if a central protein is affected, the consequences can be particularly severe. Even a small disruption in this protein can cause a cascade of failures in various systems. The more central a target protein is in the cellular network, the greater the potential harm from its damage.

The researchers tested whether this model could be used to predict real-world health risks. They compared their network predictions with large datasets on environmental and health conditions across Europe. The results were revealing. In countries where the level of certain exposures was higher, diseases associated with these exposures at the molecular level were more common. This means that the biological distance between a substance and a disease (measured within the network) helps to predict which health effects are most likely.

According to Jörg Menhe, the study offers a new perspective on the impact of the environment on health. Instead of analyzing each chemical individually, it now allows us to see how different exposures converge on common biological pathways, forming a complex yet orderly system of connections. Thanks to this map, scientists will be able to predict the effects of even those substances that have not yet been sufficiently studied.