There is no shortage of scientists toiling away in the field of anti-aging, searching for the key mechanisms behind the process and new ways to apply the brakes. This line of inquiry has turned up yet another interesting discovery, this time demonstrating how a certain chemical compound works to keep cells active and young, providing yet another target for drugs that promote this cellular behavior.
The research was carried out at University of Southern California and focuses on a kind of cell known as a senescent cell. Much aging-related research focuses on these, as they are key players in how humans grow old. Essentially, these are cells that have ceased the ability to divide and are therefore thought to be a key driver in age-related decline, along with conditions such as arthritis and heart disease.
"Senescent cells are effectively the opposite of stem cells, which have an unlimited potential for self-renewal or division," says lead author Alireza Delfarah. "Senescent cells can never divide again. It's an irreversible state of cell cycle arrest."
While this is a well-established function of senescent cells, the biological processes underpinning this behavior aren't so well understood. To investigate this, the team performed an analysis of the metabolic pathways in epithelial cells that had become senescent.
This led the researchers to discover that the cells had stopped producing a class of chemical compounds called nucleotides. These are the building blocks of DNA, and the researchers found through further experiments that when they intervened to stop the cells producing nucleotides, they indeed went on to become senescent.
"This means that the production of nucleotides is essential to keep cells young," Delfarah says. "It also means that if we could prevent cells from losing nucleotide synthesis, the cells might age more slowly."
That is easier said than done, but the discovery marks an important step in this direction. If we understand how and why cells become senescent, then we may be able to design drugs that target those particular machinations. But equally important, identifying what makes these cells unique will make it easier to design drugs that selectively target them and not other healthy ones.
These medications are part of a class of drugs called senolytics, which focus on eliminating senescent cells for healthier aging. Last year, scientists made a breakthrough in this area, demonstrating a new type of senolytic compound that could slow down the deterioration of aging mice with just three days of treatment.
The thinking with this kind of research isn't necessarily to stop aging altogether, but to make aging in humans a more palatable experience by keeping us fitter and healthier for longer. Senescent cells are implicated in a range of age-related conditions, so new methods of clearing them away or preventing their buildup in the first place could open up some exciting possibilities.
"To drink from the fountain of youth, you have to figure out where the fountain of youth is, and understand what the fountain of youth is doing," says study author Nick Graham. "We're doing the opposite; we're trying to study the reasons cells age, so that we might be able to design treatments for better aging."
The research published in the Journal of Biological Chemistry.
