The study found that oxidation a type of damage to cells caused by free radicals can damage certain kinds of messenger RNA in the brain. That damage may be related to Alzheimer's.
Messenger RNA (or mRNA) is important because it turns DNA's genetic code into the proteins needed for healthy brain function. But in an Alzheimer's brain, up to half of the mRNA are damaged by oxidation; these oxidized mRNAs may process proteins abnormally, which may contribute to neuronal death.
"We know that free radicals can damage DNA, but nobody had looked at the effect of free radicals on RNA," said C. Glenn Lin, the study's lead author and an assistant professor of neuroscience at Ohio State. "When we looked for mRNA in the Alzheimer's brain, we found significant amounts of oxidized mRNA in the frontal cortex, which is one of the main areas affected by the disease."
The researchers looked at the brains of deceased Alzheimer's patients and found that only certain kinds of mRNA are susceptible to oxidative damage. There are many, some of which researchers have yet to discover, Lin said.
This is the first study to describe the specific types, or species, of mRNA oxidized in Alzheimer's disease; until this point, researchers knew that the oxidation of mRNA played a role in Alzheimer's disease, but they didn't know which species were at fault.
Lin and Ohio State colleagues Xiu Shan and Hirofumi Tashiro, both with the department of neuroscience, reported their findings on November 10 in New Orleans at the annual Society for Neuroscience conference.
The researchers used tissue taken from the brains of 11 recently deceased Alzheimer's patients (aged 65 to 86); seven age-matched controls; and two young control subjects (aged 22 and 49). Using a series of biochemical testing methods, they
Contact: C. Glenn Lin
Ohio State University