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 hildren’s
researcher Bruce
Yankner, MD, PhD, was in the limelight this month with
the first study to reveal the genetic “signature” of
an aging brain – and the sobering news that damage to genes
essential for brain function can start anytime after age 40. His
report, in the June 9th online edition of Nature, was picked
up by multiple media outlets including The Wall Street Journal,
the Associated Press, Newsday, USA Today, New England Cable
News, and CNN.
Yankner, professor in the Department
of Neurology and Division
of Neuroscience, led a team that analyzed brain tissue from
30 deceased people ranging from 26 to 106 years old. The team first
used a technique called transcriptional profiling, which measures
the activity of thousands of genes at a time to discern an overall
pattern. Two groups of genes showed marked differences in activity
in the older brains: activity dipped in genes involved in learning
and memory, and subsequently increased in genes linked to repair
of damaged genes and brain proteins. The researchers then showed
that the less-active genes had been damaged and didn’t function
properly. Yankner believes the surge in repair-gene activity is
the brain’s way of trying to compensate for this damage, which
he thinks comes from agents in the environment.
The brain’s genetic signatures were fairly consistent among
both younger people and very old people, but variability from person
to person was much greater in the 40-to-70 age group. “People
may diverge in their rates of aging as they enter middle age,”
Yankner says. “A goal of future research will be to understand
why.” In the laboratory, Yankner’s group was able to
prevent gene damage in nerve cells by engineering them to make more
gene-repair proteins. The group now wants to prevent the same damage
in the living brain, to preserve cognitive function and keep diseases
like Alzheimer’s
at bay.
Coauthors on the Nature paper included postdoctoral fellows Tao
Lu (the paper’s first author), Ying Pan, and Shyan-Yuan Kao
in the Division of Neuroscience; Isaac Kohane, MD, PhD, director
of the Children’s
Hospital Informatics Program (CHIP); and Cheng Li,
PhD, from the Department
of Biostatistics at the Harvard School of Public Health.
Funding was provided by the National
Institute on Aging and the National
Institute of Neurological Diseases and Stroke.
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