Washington: Researchers have identified a specific set of microRNAs that detrimentally regulate protein levels in the brains of mice with Alzheimer's disease and beneficially regulate protein levels in the brains of other mice living in a stimulating environment.
Plaques and tangles made of proteins are believed to contribute to the debilitating progression of Alzheimer's disease.
Molecules called microRNAs regulate both good and bad protein levels in the brain, binding to messenger RNAs to prevent them from developing into proteins.
"We were able to create two lists of microRNAs- those that contribute to brain performance and those that detract- depending on their levels in the brain. By targeting these molecules, we hope to move closer toward earlier detection and better treatment of Alzheimer's disease," Dr. Boaz Barak form Tel Aviv University said.
The TAU researchers became interested in the disease while studying the brains of mice living in an "enriched environment"- an enlarged cage with running wheels, bedding and nesting material, a house, and frequently changing toys.
The researchers ran a series of tests on a part of the mice's brains called the hippocampus, which plays a major role in memory and spatial navigation and is one of the earliest targets of Alzheimer's disease in humans.
They found that, compared to mice in normal cages, the mice from the enriched environment developed higher levels of good proteins and lower levels of bad proteins. Then, for the first time, they identified the microRNAs responsible for regulating the expression of both good and bad proteins.
The researchers analyzed changes in the levels of microRNAs in the hippocampi of young, middle-aged, and old mice with an Alzheimer's-disease-like condition. They found that some of the microRNAs were expressed in exactly inverse amounts in mice with Alzheimer's disease as they were in mice from the enriched environment.
The results were higher levels of bad proteins and lower levels of good proteins in the hippocampi of old mice with Alzheimer's disease.
The study is published in Translational Psychiatry.