Yeast cells on a diet live longer, as do their neighbors.
A substantial part of one of the earliest works of human literature, the Epic of Gilgamesh, details the search of the eponymous hero for eternal life. Throughout history, stories that revolve around the desire for immortality keep turning up. Of course, all that is fiction.
Fountain of youth
Still, some scientists have been looking for the fountain of youth, mostly at the fringes (or beyond) of the scientific enterprise, often ridiculed by their more ‘serious’ colleagues. No more. The past few decades, research to understand and combat aging has steadily elbowed its way into the arena of respectable science, often referred to as biogerontology. To understand the causes of aging and uncover potential interventions has become a growing research field and, in some cases, big business.
It is important, though, to keep in mind that it’s not just about getting older, but about doing so healthily. In other words, the goal of these investigations is not solely to increase lifespan, but to lengthen ‘healthspan’. And to achieve this, several routes have been proposed, from drugs and chemicals to dietary interventions. Prime among these latter ones is caloric restriction, or eating (a lot) less. This has been shown to (sometimes dramatically) increase the lives of lab animals, whether it concerns tiny roundworms or mice. (Before you rush off to starve yourself: for now, the evidence in humans and other primates is ambiguous at best, and, additionally, several researchers are working on drugs that mimic the caloric restriction effect…)
Anyway, drugs or dieting, it only affects you. Or does it?
Yeast on a diet
A new study, published in PLoS Biology, shows that caloric restriction in yeast benefits not just the dieting cells, but others as well.
When yeast cells are put on a low glucose diet, their life- and healthspan increases. The exact mechanism, however, remains a mystery. Previous research suggests that some of the chemicals involved might find their way out of the dieting cells.
To test this idea, researchers from the University of Iowa put yeast on a diet. Lo and behold, the cells lived longer. But what was interesting was that when these cells were moved to new locations, equally glucose-scarce, they lost the caloric restriction benefits. The authors, however, did find two ways to maintain the lifespan-enhancing benefits of caloric restriction: add NA (nicotinic acid) or NR (nicotinamide riboside), both chemical substances known to be involved in yeast life extension, or, and this is the odd bit, transplant bits of the environment in which previous caloric restricted cells were grown.
So, yeast cells that are put on a diet produce a certain molecule that leaves their cells and can confer the ‘longer life benefits’ to others. Furthermore, the molecule is not NA or NR, as the researchers tested for this. At the moment, all they can say is that it’s a rather small one.
Yeast cells on a diet do not only live longer, they extend their neighbors’ lifespan as well, giving them the gift of a longer life.
Mei, S., & Brenner, C. (2015). Calorie Restriction-Mediated Replicative Lifespan Extension in Yeast Is Non-Cell Autonomous PLOS Biology, 13 (1) DOI: 10.1371/journal.pbio.1002048