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A Genetic Basis for Stress and Illness

The work coordinated by Lucia Piacentini and Arianna Rinaldi at the “Charles Darwin” Department of Biology and Biotechnology at Sapienza University suggests that there may be a genetic basis for illnesses caused by strong emotional stress. The researchers observed that in mice – a model animal that resembles mankind in terms of molecular characteristics – prolonged exposure to stressful conditions can induce the activation of uncontrolled mobile genetic elements (transposons) and serious consequences on the organisms. The results of the study have been published on StressThe International Journal on the Biology of Stress.

Trasposons, also known as “jumping genes,” which were discovered in the fifties by Barbara Mc Clintock, are mobile genetic elements that can move autonomously around the genome and change their position not only within the same chromosome but also in different chromosomes. Due to their ability to finely modulate reprogramme the expression of complex genetic networks, transposons represent an optimal tool for genomes to functionally adapt to change and environmental stress. Moreover, they certainly played an important role in the creation of modifications and genetic variability over the course of human evolution.

However, for these transposable elements to co-evolve with their hosting genome, their mobility must be finely regulated as an elevated transposition activity can cause genomic instability and the alteration of numerous genes with deleterious effects on organisms.

“We studied the effect of prolonged stress (2 hours a day for 5 days) on mice,” explains Lucia Piacentini. “We observed the activation of Line-1 transposons in the hippocampus, one of the areas in the brain dedicated to perception and the elaboration of stressful events, while no other significant alteration was observed in other brain areas.” These results indicate that, in mice, the control of transposon expression represents an additional mechanism for physio-pathological stress response, demonstrating that their regulation is closely related to the genetic background of individuals and in a specific brain area.

The study opens interesting prospects on the role of transposons in illnesses and human ageing. In particular, the demonstration of a differential transposon activation amongst different tissue cells can help us understand why certain types of stress increase our risk of illness, but not in others, such as post-traumatic stress disorders of ischemic cardiopathy.

Reference:

Stress-induced Strain and Brain Region-specific Activation of LINE-1 Transposons in Adult Mice - Ugo Cappucci, Giulia Torromino, Assunta Maria Casale, Jeremy Camon, Fabrizio Capitano, Maria Berloco, Andrea Mele, Sergio Pimpinelli, Arianna Rinaldi & Lucia Piacentini, Stress, The International Journal on the Biology of Stress, Published online: 11 Jul 2018. DOI: 10.1080/10253890.2018.1485647