Extra Gene Brings Longer Life

Researchers extended the lifespan of the fruit fly by giving it an extra gene that boosted its ability to clean up toxic wastes in its cellular house, an approach that experts called potentially promising in stemming the ravages of aging and disease.

The key to the research was targeting the nerve cells that control movement.

By giving fruit flies an extra gene that increased the ability of their motor neurons to eliminate waste products from natural metabolism, Canadian researchers extended the insects' lifespans by as much as 40 percent.

Providing a fly, which usually survives 80 days, with another month on the planet by manipulating one gene may not sound like much, but the implications are vast, the authors and outside researchers said.

"It really speaks very optimistically for our ability to directly intervene into the aging process in other higher animals, including humans," said Tom Johnson, a professor at the Institute for Behavioral Genetics at the University of Colorado at Boulder. Johnson was not connected to the research.

But whether it will work in mice or humans remains to be seen, said lead researcher Gabrielle Boulianne, a neurobiologist at the Hospital for Sick Children and an associate professor of molecular and medical genetics at the University of Toronto.

The findings, released Monday, appear in the June issue of the journal Nature Genetics.

They suggest "the nervous system is a primary target of aging," Boulianne said.

That implies nerve cells that control muscles (the very ones attacked by several degenerative illnesses like Lou Gehrig's disease and Alzheimer's disease) may be the most vulnerable of all cells in the body, she said.

Boulianne said the results mark the first time researchers have shown a single gene in a single type of cell can affect longevity.

"We were really surprised," she said. "We never expected manipulating a single gene like this would have such profound effects on lifespan."

The work stems from the central fact that oxygen is toxic. While oxygen provides living things with their energy, its byproducts produce cell damage and death. You might think of that damage as cellular rusting.

All the cells in insects and animals naturally produce an enzyme called superoxide dismutase that converts wastes produced by oxygen metabolism into harmless byproducts.

Boulianne, who develops fly models of neurodegenerative diseases, knew that disorders like Lou Gehrig's and Alzheimer's are caused by mutations in the gene that tells cells to make the enzyme.

She began wondering what would happen if she enhanced the nerve cells' ability to eliminate the wastes.

So, she gave flies copies of the human SOD1 gene, which instructed their cells to make extra enzyme. When the nerve cells made more enzyme, the flies lived longer.

Written by Jane E. Allen
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