One of the hallmarks of Alzheimer’s disease is a reduction in the firing of some neurons in the brain, which contributes to the cognitive decline that patients experience. A new study from MIT shows how a type of cells called microglia contribute to this slowdown of neuron activity.
The study found that microglia that express the APOE4 gene, one of the strongest genetic risk factors for Alzheimer’s disease, cannot metabolize lipids normally. This leads to a buildup of excess lipids that interferes with nearby neurons’ ability to communicate with each other.
“APOE4 is a major genetic risk factor, and many people carry it, so the hope is that by studying APOE4, that will also provide a bigger picture of the fundamental pathophysiology of Alzheimer’s disease and what fundamental cell processes have to go wrong to result in Alzheimer’s disease,” says Li-Huei Tsai, director of MIT’s Picower Institute for Learning and Memory and the senior author of the study.
The findings suggest that if researchers could find a way to restore normal lipid metabolism in microglia, that might help to treat some of the symptoms of the disease.
MIT postdoc Matheus Victor is the lead author of the paper, which appears today in Cell Stem Cell.
About 14 percent of the population has the APOE4 variant, making it the most common genetic variant that has been linked to late-onset, nonfamilial Alzheimer’s disease. People who carry one copy of APOE4 have a threefold higher risk of developing Alzheimer’s, and people with two copies have a tenfold higher risk.
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