Bodies in Crisis: How Toxic Chemicals and Climate Change Are Affecting Our DNA

Associate Professor of Biology Gretchen Edwalds-Gilbert has spent her career stressing out cells. By exposing them to different chemical and environmental insults, she aims to find out how they adapt—or fail to adapt—to the biological realities of the modern world. “It’s fundamental to see how we adapt to different stressors, like temperature, nutrition, pollution, or toxins,” says Edwalds-Gilbert. “I’m a molecular biologist, so instead of looking at the whole human, I’m studying how genes are changing under different conditions, which can shed light on how individuals or species can adapt to a changing world.” She and colleagues already have found that gene expression, or how DNA becomes an activity or product, can change under certain cellular conditions. They found that some stressors activate the “unfolded protein response” (UPR)—a phenomenon in which the proteins within a cell become so overloaded with stress that they unfold and are no longer active. Properly folded proteins are responsible for most cellular functions, including cleanup, reusing or destroying cellular “trash.” But when a cell becomes stressed, the process by which the DNA becomes protein is interrupted, and the DNA responsible for cell cleanup turns off.
The researchers tested the UPR by treating cells with certain phenols, such as the well-known food and cosmetics preservatives BHA and BHT, as well as the ubiquitous chemical BPA, which is contained in everything from plastics to receipts to the food we eat and drink. They found that a key protein required for unfolding became activated after these chemical assaults and did not “turn off” again, signaling to the cells that the problem was too big to fix. The cells, inundated with waste, activated apoptosis: programmed cell death. Now, Edwalds-Gilbert is furthering her exploration of the UPR and other cellular waste management phenomena through a line of research aimed at understandinghow cells respond to the unique assaults of climate change, including greater water salinity, higher temperatures, altered nutrition, and higher concentrations of pollutants. “Within the scientific community, it is generally acknowledged that climate change will expose organisms—people, plants, and animals—to novel environments that will cause stress to the body,” says Edwalds-Gilbert. “Increased heat, for example, can lead to dehydration and overheating. We know how to treat that in a whole human organism—take off a person’s clothes, increase the consumption of fluids—but what’s going to happen at the molecular level, and can that be treated?” Edwalds-Gilbert is conducting this research at the Institute of Genetics and Biotechnology at the University of Warsaw in Poland, where she is currently a Fulbright fellow. As a basic scientist, she explores these responses at a molecular level; however, the more she and colleagues can illuminate the cellular responses to environmental and chemical stress, the better equipped physicians and researchers will be to start taking actions to help regulate the UPR. “We hope to take a bench-to-bedside approach—that is, to share our research with those scientists who develop therapeutics for use in whole human organisms. So, the question is, can we target the UPR therapeutically? The UPR is interesting because the response is highly associated with a number of human diseases, including cancer and neurodegenerative disorders. Right now, this stuff isn’t even in textbooks, and climate change is occurring more quickly than scientists thought. We need to start seeing how human bodies are going to adapt.”