A new study developed by researchers at the Icahn School of Medicine at Mount Sinai (USA), has shown that male mice with a tendency to stress – those that get stressed more easily than others – transmit these behaviors to their children through the sperm, modifying gene expression and passing from one generation to another.
This work expands on previous research that showed how stressful events can alter gene expression in mice, leading to behavioral changes that can be passed down from generation to generation. It was a 2020 study, published in Nature Communications , that suggested that stress alters cellular components involved in sperm development, potentially changing the way sperm influence stress-related traits in offspring.
Stressful experiences alter gene expression, which parents can pass on to their children, but it was unclear whether the sperm itself carried this information or whether behavioral cues between parents played a larger role.
New analysis with stress exercises
The researchers tracked the stress response of male mice after ten days of chronic stress and classified them into resistant and susceptible groups, based on the severity of their response. The offspring of the more stress resistant and control mice showed reduced stress behaviors compared to the offspring of the more stress prone mice.
The same pattern appeared in offspring conceived by artificial insemination, indicating that sperm play a direct role in transmitting stress responses. The researchers also sequenced the RNA in the father’s sperm, the transcriptome, before and after chronic stress. Stress changed 1,460 genes in mice susceptible to stress, but only 62 genes in mice with greater stress inflexibility. These results reveal that sperm transmits short-term environmental information to offspring through changes in the transcriptome.
The current findings could have implications for understanding the heritability of generational stress and trauma in humans, as well as the source of various mood disorders, along with updated treatment goals.
Previous studies had not considered variation between the way different mice react to stress. “Our study is the first to segregate parents into resistant and susceptible groups,” says Ashley Cunningham, co-author of the work. “I think that is very important because people are complicated and those who go through the same stressors are not going to have the same answer.”
For future research, experts want to better understand how long the effects of stress last on offspring. To do that, they would try to see how many litters the parents can have, if they continue to transmit the traits that show a stronger stress response and what echo this factor has in the brain of the progeny.
Referencia: Sperm transcriptional state associated with paternal transmission of stress phenotypes. Ashley M. Cunningham, Deena M. Walker, Aarthi Ramakrishnan, Marie. A. Doyle, Rosemary C. Bagot, Hannah M. Cates, Catherine J. Peña, Orna Issler, Casey Lardner, Caleb Browne, Scott J. Russo, Li Shen and Eric J. Nestler. Journal of Neuroscience (2021).DOI:https://doi.org/10.1523/JNEUROSCI.3192-20.2021
