Fly stem cells give insights into aging and longevity

Yesterday brought news about stem cells in older people. Today, there's news by CIRM grantees about how a single gene alteration in a stem cell can help keep an entire organ more youthful -- at least in flies.

The work was by a team of researchers at the University of California, Los Angeles, the Salk Institute for Biological Studies and the University of California, San Diego. It all started with a long-known observation: cutting calories in many laboratory animals can also dramatically extend the animal's life. This is true in common lab animals such as flies, worms, and mice, and also holds true in primates.

In addition to living longer, those hungry, long-lived animals have more of the energy-producing cellular structures called mitochondria. The researchers were curious if simply boosting the number of mitochondria without all that painful hunger would work the same trick. One known way of boosting mitochondria is to rev up a protein called PGC-1.

A press release from Salk describes the work of associate professor Leanne Jones' work like this:

"This chain of connections between the mitochondria and longevity inspired Jones and her colleague to investigate what happens when the PGC-1 gene is forced into overdrive. To do this, they used genetic engineering techniques to boost the activity of the fruit fly equivalent of the PGC-1 gene. The flies (known as Drosophila melanogaster) have a short lifespan, allowing the scientists to study aging and longevity in ways that aren't as feasible in longer-lived organisms such as mice or human."

The researchers specifically bumped up the PGC-1 gene in stem cells that line the fly intestine. They found two things: 1) those fly intestine stem cells had more mitochondria, and 2) the flies lived a lot longer than their unaltered lab-mates. All that, with no starvation.

Here, I should pause to say that if you think your intestine is so different from a fly's you'd be wrong. Their intestine is lined with stem cells not unlike our own, and those cells function in a very similar way using similar genes. That's not to say that all research in flies directly translates to humans, but it is a pretty good model for testing out ideas.

Jones, who has a New Faculty award from CIRM, had this to say in the press release about the findings:

"Slowing the aging of a single, important organ - in this case the intestine - could have a dramatic effect on overall health and longevity," Jones says. "In a disease that affects multiple tissues, for instance, you might focus on keeping one organ healthy, and to do that you might be able to utilize PGC-1."

This research is in the very preliminary stages and is far from being ready for an human use. However, it's this kind of basic discovery that continuously fuels new ideas for human therapies.

CIRM Funding: Leanne Jones (RN1-00544-1)
Cell Metabolism, November 1, 2011

- A.A.