Docosahexaenoic acid prevents neuronal apoptosis induced by soluble amyloid-beta oligomers

A growing body of evidence supports the notion that soluble oligomers of amyloid-beta (A beta) peptide interact with the neuronal plasma membrane, leading to cell injury and inducing death-signalling pathways that could account for the increased neurodegeneration occurring in Alzheimer's disease (AD). Docosahexaenoic acid (DHA, C22:6, n-3) is an essential polyunsaturated fatty acid in the CNS and has been shown in several epidemiological and in vivo studies to have protective effects against AD and cognitive alterations. However, the molecular mechanisms involved remain unknown. We hypothesized that DHA enrichment of plasma membranes could protect neurones from apoptosis induced by soluble A beta oligomers. DHA pre-treatment was observed to significantly increase neuronal survival upon A beta treatment by preventing cytoskeleton perturbations, caspase activation and apoptosis, as well as by promoting extracellular signal-related kinase (ERK)-related survival pathways. These data suggest that DHA enrichment probably induces changes in neuronal membrane properties with functional outcomes, thereby increasing protection from soluble A beta oligomers. Such neuroprotective effects could be of major interest in the prevention of AD and other neurodegenerative diseases.