What impacts do endocrine disruptors have on the epigenome?

This text is part of the special section Higher education

Stress, diet, drugs, chemicals in our environment: several factors can have an impact on the expression of our genes and on the development of diseases. In her laboratory at the National Institute for Scientific Research (INRS), researcher Geraldine Delbès forges links between endocrine disruptors and male fertility and, at the same time, contributes to advancing a science that is still in its infancy. stammering.

“All the cells in your body have the same DNA and yet they don’t look alike: you’ve made hair, eyes, skin, liver. The code was not read the same in different parts of you. What made this possible is the epigenome, explains Géraldine Delbès, expert in reproductive toxicology at INRS. Genetics is the code. With epigenetics, we learn how “we read the book”, this is the reading code. “

What we are discovering today is that this reading code is extremely complex. There are several molecular mechanisms that combine, that speak to each other, and this creates thousands of possibilities, continues the researcher.

“But from the moment we start playing with the reading code, we can have a multiplied capacity for diagnoses and treatment of diseases,” she explains. DNA is difficult to change, while the beauty of the epigenome is that it is reversible. There is a huge potential to change the quality of someone’s life, it’s crazy! “

If the potential of epigenetics is great, it is still a young science, located at the convergence of several disciplines. One of the first scientific studies to have caused a wave in the scientific community to demonstrate the transgenerational effects of a product on rodents barely dates from 2005, illustrates Mme Delbès. The researcher, who has training in reproductive physiology and toxicology, is particularly interested in the effects of endocrine disruptors on the fertility of various generations of male rodents. She is also participating in a multidisciplinary project aimed at mapping chemical cocktails in the air of Montreal.

“Toxicology makes use of all the fundamental advances in order to be able to predict the toxicity of a compound”, explains Géraldine Delbès, referring in particular to progress in molecular biology and genetics. Breakthroughs in epigenetics help us better understand the phenomena of exposure. “

A disturbed reproduction

“We want plastic, we want cellphones, but ultimately these are sources of chemicals that we do not know. If I am pregnant, endocrine disruptors will enter me, through what I eat, what I touch, perhaps what I breathe, and this will directly affect the environment of the fetus, ”continues Geraldine. Delbès, who recalls that these substances which disrupt hormonal functioning can cross the membranes of the placenta.

If women are generally informed and avoid exposure to various substances during their pregnancy, this is not always the case for men, who also can transmit “environmental” information during reproduction, observes the researcher. The sperm transmits not only its DNA, but also its epigenome, which can be affected by various factors. “Both gametes come with a story, and that can create an embryo that doesn’t develop and causes a miscarriage,” says M.me Delbès.

Passionate and involved

Between her family life and her work at INRS, Géraldine Delbès’ passion does not tarnish. For several years, the researcher has been involved in her work environment in an institutional EDI committee (Equity, diversity, inclusion). “We created scholarships for students from developing countries, parental leave scholarships, we did webinars to educate our members and tackle a bunch of topics, like impostor syndrome, systemic racism. , women in science, etc. », Says the one who is also interested in the representativeness of the LGBTQ community in the university world.

“There really isn’t a model for the LGBTQ community at university,” she notes. I consider myself extremely lucky to have this job, and I find this motivation more and more through multisectoral projects and a host of societal questions relating to equity, diversity and inclusion in the research community. “

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