TORONTO -- A research team led by Dr. Gabrielle Boulianne of The Hospital for Sick Children (HSC) and the University of Toronto ( U of T) and Dr. John Phillips of the University of Guelph has identified a critical weakness in the defence against aging. Using the fruit fly as a model biological system, the researchers discovered that a specific cell type the motor neuron is the major target for oxidative damage, known for several years to be a key factor affecting aging and lifespan. The researchers were able to boost the flies' defences by inserting a human gene which is known to protect against oxidative damage. As a result, the average lifespan of the flies (usually about 80 days) was increased by 40 percent.
"This research is significant because it clears up a long-standing mystery: which cells, when targeted by oxidative damage, limit the lifespan of the entire organism," says Dr. Boulianne, a scientist at HSC and an associate professor of Molecular and Medical Genetics at U of T. "In addition, we now know that just one gene, targeting one type of cell, has a huge impact on aging. Contrary to what was previously thought that many different factors contribute to aging it now appears that the process may be simpler."
By inserting the human gene SOD1 (superoxide dismutase) into flies, researchers were able to protect the flies against oxidative damage. This damage, which increases with aging, affects a cell's ability to maintain its structure and function.
"One of life's ironies is that the stuff that we need to survive oxygen is actually toxic," explains Dr. Phillips. "When we breathe, toxic by ADproducts called oxygen radicals are created. Our cells defend against these toxins by either neutralizing or eliminating them. But as we age it becomes more difficult for our cells to cope with the toxins and they accumulate. What we now know is that the nervous system is the most vulnerable to this accumulation because it uses a lot of oxygen."