A team of researchers, led by scientists at the University of North Carolina, Chapel Hill, with support from the National Institute on Aging at the NIH, has developed an innovative approach to study aging cells in living mice. The approach is described in the January 17, 2013, issue of Cell.
The researchers designed a strain of mice whose p16 gene is tagged with a luminescent gene derived from the firefly. As a result, the p16 gene glows in areas of the body where the gene is active—the more cells expressing the gene, the more intense the glowing effect.
The p16 gene is best known as a tumor suppressor and is primarily active in senescent cells. Cell senescence, a state in which cells stop dividing but maintain a limited function in the body, may protect against cancer. In cancer, cells divide and proliferate without control. However, research suggests that cell senescence may also contribute to some of the negative effects of aging.
Researchers found an exponential increase of p16 as mice aged, supporting the relationship between senescence and aging. But the p16 levels were varied, suggesting factors beyond genetics, diet and lifestyle may play a part in determining how well mammals age. The expression of p16 did not predict cancer or aging-related death, leading researchers to suspect that an accumulation of senescent cells is not the main cause of mortality.
Researchers conclude that findings from this work support p16 as a potential indicator of aging and this new strain of mice may be helpful in determining the effects of compounds on aging cells.
Reference: Burd, Christin E., et al. Monitoring Tumorigenesis and Senescence In Vivo with a p16INK4a-Luciferase Model. Cell. 2013 Jan 17; 152(1-2):340-351. Epub 2013 Jan 17.