Biologists at the University of California, Santa Barbara have published a study examining how fruit flies extend the lifespan of their germline stem cells.

Researchers have described a process that stops egg production in female flies. Scientists have found that in this way insects can extend the viability of stem cells.

We are interested in how to extend the lifespan of stem cells in general and female germline stem cells in particular.

Denise Montell, Duggan Professor

When fruit flies grow up and face constant cold or darkness, for example, they go into a dormant state called diapause. This is a seasonal reaction – it saves energy for reproduction.

Diapause can double a fly’s lifespan and greatly extend its reproductive period. Flies in diapause eat less, are less active, and suspend their reproductive processes, but they do not actually hibernate.

We studied this process in detail and its cell biology, which turned out to be very interesting. A detailed study may give us the key to understanding how to slow down the aging of stem cells.

Srisankar Iswaran, Project Scientist at Montella Lab.

Female flies under stress stop oogenesis – egg production – at a certain stage of egg development. The authors found that this also occurs during diapause, but goes beyond this stage. The arrest of oogenesis was much more complete during diapause than in other stressful situations, such as when predators were present or when there was a lack of protein. It is also important that, under conditions of oogenesis, the restoration of reproductive ability was more active.

If you compare growing eggs to installing new software, the stress response is like pausing a download. In this analogy, diapause is like completing an installation and restarting the process.

The researchers wanted to see if it was possible to artificially extend the lifespan of germline stem cells: They removed the cells that produced the juvenile hormone that stopped egg production, and then reintroduced the hormone into the flies’ food six weeks later. They found that temporary removal of the hormone expanded the flies’ reproductive potential, similar to diapause, and egg production was restored when the compound was reintroduced.

Now the researchers want to find out if it’s possible to replicate this effect in humans.