The study, published in Nature Neuroscience, focuses on apolipoprotein E (APOE), a gene long known to play a major role in Alzheimer’s disease. The team created a first-of-its-kind mouse model that allows scientists to “flip a switch,” changing the high-risk version of the gene (APOE4) to the protective form (APOE2) in adult animals.

Switching genes shows dramatic benefits

People who inherit APOE4 have up to a 15 times greater risk of developing Alzheimer’s, while those with APOE2 tend to have lower risk and better cognitive outcomes. In the new study, when researchers activated the gene switch in brain cells called astrocytes, the mice showed striking benefits: fewer Alzheimer’s-related brain changes such as amyloid plaque buildup and inflammation, and stronger performance on memory tests.