Lysosomes are cellular sanitation engineers that help clean up and recycle internal debris no longer needed by cells. So why do researchers find so many lysosomes within the neuronal projections surrounding amyloid plaques, a hallmark of Alzheimer’s disease brain pathology?

“We didn’t know whether these accumulations of lysosomes represented a beneficial response of neurons to the amyloid plaque disease pathology or whether they were somehow deleterious,” said Shawn Ferguson, associate professor of cell biology at Yale.

Ferguson and colleagues investigated how neurons control distribution of lysosomes and used the knowledge to increase lysosomes in neural projections in a mouse model of Alzheimer’s. They found that the additional lysosomes greatly accelerated formation of amyloid plaques. The findings suggest that reducing the build–up of lysosomes within neurons might be a novel way to treat dementia, said the researchers.

The research was published Aug. 7 in the Journal of Cell Biology.