Human beings encounter stress on a daily basis. Ideally, the brain is able to process stressful events so that a person can cope and continue with their life. However, defects in the brain's ability to process psychological stress or an excess of stress can increase a person's likelihood of developing depression or PTSD.
A recent study from the Okinawa Institute of Science and Technology in Japan, published in the peer-reviewed journal Nature, showed that an estimated 50% of adults experience a traumatic event in their lifetimes, and put forward that "it is imperative that we investigate mechanisms that underlie stress responses and identify potential therapeutic targets coordinating stress resilience."
Researchers identified a gene, dubbed TOB, which has been proposed to regulate learning and memory. Critically, it is also one of the early response genes in times of stress and decreased expression of the TOB gene has been associated with depression.
“Although it was previously suspected, this research is the first work that clarifies that Tob has a function in the brain against stress.”
Prof. Yamamoto, lead researcher
“This research is about understanding stress-resilience,” explained lead author, Dr. Mohieldin Youssef, former PhD student in OIST’s Cell Signal Unit, which is led by Prof. Yamamoto. “The presence of the gene helps with stress-resilience and if it’s removed, there’s an increase in depression, fear, and anxiety.”
Where does the name come from?
The name of the gene is derived from the Japanese word tobu which means to fly or to jump. This is because when the cell is exposed to stimuli, its protein levels jump drastically in activity levels.
“The Tob gene is related to many different phenomena but working on the brain system is particularly challenging,” said Prof. Yamamoto. “Although it was previously suspected, this research is the first work that clarifies that Tob has a function in the brain against stress.”
The study itself was conducted using mice, some of which had their TOB protein inhibited via selective breeding. The mice were exposed to various stressful situations and then eventually sacrificed in order to examine their hippocampi to determine their protein levels.
“We’ve concluded that the Tob gene within the hippocampus suppresses fear and depression,” explained Dr. Youssef. “But the suppression of anxiety must be regulated by another part of the brain.”
The experiment's results demonstrated that the TOP gene plays an important role in coping with stress. Increased levels of TOB protein in mice after being exposed to acute stress, along with abnormal behavior in those whose ability to produce the protein was dampened, led researchers to the conclusion that this gene is critical for coping with highly stressful situations healthily.
“Uncovering this role of the Tob gene in fear, depression, and anxiety could have vast implications for developing therapeutics for psychiatric stress,” concluded Dr. Youssef.