What Doesn't Kill You Makes You Stronger!
"What does not kill you makes you stronger." It's not just a saying, it is true. Researchers have pinpointed a cell recycling process tied to the positive effects of moderate stress. Meaning you shouldn't necessarily worry about mild stresses. Anything from going for a jog to spending some time in the sauna can help your health and longevity.
A new study could help explain why brief bodily stresses -- going to the sauna or for a run, for example -- are good for health and longevity. A study shows that the same cellular process, called autophagy, that's key for extending lifespan is also critical to the benefits of temporary stress.
Science have known for decades that enduring a short period of mild stress makes simple organisms and human cells better able to survive additional stress later in life. Recently, researchers have discovered a key cellular process that’s critically involved in providing the benefits of temporary stress. The study, published in Nature Communications, creates new avenues to pursue treatments for neurological disorders such as Huntington's disease.
"We used C. elegans -- tiny roundworms used to study fundamental biology -- to test the importance of autophagy in becoming stress resistant," says Caroline Kumsta, Ph.D., staff scientist in Hansen's lab and lead author of the study. "They're a great model system because they're transparent, so you can easily observe what goes on inside them, most of their genes and molecular signaling pathways have functional counterparts in humans, and they only live a few weeks, which greatly facilitate measuring their lifespans."
Researchers found that the cellular process important for boosting lifespan, known as autophagy, is also important for obtaining benefits from stress. Biologists have known for quite a long time that brief episodes of moderate stress empower simple organisms as well as cells within human beings to better survive stress at later points in life. The recent research conducted by scientists at the Sanford Burnham Prebys Medical Discovery Institute has shed new light on this truth. These researchers found that autophagy really does benefit the body when stress occurs. Their study was recently published in Nature Communications.
What is Autophagy?
Autophagy is best described as a way to recycle cells' broken, aged and unnecessary structures so they can be used to create new molecules or even burned to create energy. Scientists previously linked this process to longevity. The results of the new research connect stress resistance and long life on a cellular level. Autophagy is a means of recycling cells' old, broken, or unneeded parts so that their components can be re-used to make new molecules or be burned for energy. The new results suggest that long life and stress resistance are connected at the cellular level
The study's lead author, staff scientist Caroline Kumsta, Ph.D., states her team made use of roundworms to analyze fundamental biology.
Roundworms were used to gauge the importance of autophagy for stress resistance. Part of the reason why they were used is the fact that they are translucent so scientists can see exactly what occurs inside of them. Furthermore, the majority of roundworms' molecular signaling pathways and genes are similar to those in human beings. They live a couple of weeks which makes it easier to gauge their lifespans. These worms were incubated at 36 degrees Celsius for a full hour. After this exposure to heat (mild stress), the rate of autophagy heightened across the worms' tissues. The researchers then exposed these heated worms to a lengthy heat source a couple of days later. The worms that were autophagy-deficient did not obtain benefit from the first mild heat shock. Heated worms with intact autophagy obtained benefit from the heat shock.
Significance of the Results
Researchers concluded that a mild source of heat heightens worms' ability to endure another condition that gets worse during the aging process: the accumulation of aggregated proteins. Such a buildup is quite stressful for cells. Kumsta made use of worms that replicate Huntington's disease that causes degeneration in the brain. Exposing worms with sticky neuronal proteins (like those found in patients with Huntington's disease) to a moderate heat shock decreased protein aggregates. This suggests a moderate amount of heat stress can minimize the toxic accumulation of proteins.
The study is a massive breakthrough as it sets the stage for new approaches to treating neurological disorders like Parkinson's and Alzheimer's disease as they are also induced by the accumulation of proteins prone to clumping.
Perhaps the induction of autophagy as a result of moderate heat stress at an early stage allows cells to better survive heat exposure at a later point in time.
Heading to the sauna, going for a jog or doing hot yoga might not be a bad idea at all.
Caroline Kumsta, Jessica T. Chang, Jessica Schmalz, Malene Hansen. Hormetic heat stress and HSF-1 induce autophagy to improve survival and proteostasis in C. elegans. Nature Communications, 2017; 8: 14337 DOI: 10.1038/ncomms14337