MGH Martinos Center for Biomedical Imaging 2016 | Page 8
advances in imaging technology
Imaging The Processes Behind Gene Expression
Using a PET radiotracer they introduced only two years ago, Jacob Hooker and colleagues have performed the first imaging of the epigenetics of the human brain
Hsiao-Ying (Monica) Wey/Science Translational Medicine
A novel PET radiotracer developed
in the Martinos Center has, for the
first time, enabled imaging of epigenetic activity—the process that
determines whether or not genes
are expressed—within the human
brain. The findings were reported
in an August 2016 issue of Science
Translational Medicine.
Harvard Medical School, and senior
author of the Science Translational
Medicine report. “This could allow
us to investigate questions such as
why some people genetically predisposed to a disease are protected
from it? Why events during early life
and adolescence have such a lasting
impact on brain health? Is it possible to ‘reset’ gene expression in the
“The ability to image the epigen- human brain?”
etic machinery in the human brain
can provide a way to begin under- This accomplishment was made
standing interactions between genes possible by the PET radiotracer
and the environment,” said Jacob [11C]Martinostat, which Hooker
Hooker, Director of Radiochemis- and colleagues introduced in 2014
try in the Martinos Center, an As- to advance the study of a family of
sociate Professor of Radiology at enzymes called histone deacetylases
(HDACs). One of the jobs of these
enzymes is to change the way DNA
is packaged inside each cell—wrapping up genetic information to be
‘read’ later, at the appropriate time
and place in the organism—thus
shaping the way the information is
used without changing the DNA sequence itself.
In developing the probe, they knew
that HDACs would prove an important target. Research has shown that
changes in the amount of HDAC in
brain tissue are a prominent feature
of the changes in brain function that
result from aging and neuropsychiatric and neurodegenerative dis-