How aging-related brain diseases affect the brain

October 11, 2011

Synapses in Drosophila overgrow when exposed to oxidative stress. Left:Drosophila synapse from a normal animal; right: synapse after exposure to excessive oxidative stress. (Credit: S.Sweeney)

Research by biologists at the University of York and Hull York Medical School has revealed that under stressful conditions, such as during neurodegenerative diseases like Alzheimer’s and Parkinson’s Disease, resulting high-energy forms of damaging oxygen cause synapses to grow excessively, potentially contributing to dysfunction.

The scientists studied the responses using a model of lysosomal storage disease, an inherited incurable childhood neurodegeneration where enlarged synapses have been observed. Lysosomal dysfunction leads to poor digestion of damaged macromolecules and organelles, resulting in the accumulation of biological waste. During aging, this “waste” manifests as lipofuscin, a nondegradable agglomeration of lipids and proteins, and a hallmark of aging cells.

Laboratory modelling was carried out using Drosophila, but similar pathways are present in humans. The role that growth has in disease progression and brain function is not yet clear, the researchers advise.

Ref.: Valerie J. Milton, et al., Oxidative stress induces overgrowth of the Drosophila neuromuscular junction, PNAS, 2011; [DOI:10.1073/pnas.1014511108]