Human amyloid beta peptide and tau co-expression impairs behavior and causes specific gene expression changes in Caenorhabditis elegans

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the presence of extracellular amyloid plaques consisting of Amyloid-beta peptide (A-beta) aggregates and neurofibrillary tangles formed by aggregation of hyperphosphorylated microtubule-associated protein tau. We generated a novel invertebrate model of AD by crossing A-beta1-42 (strain CL2355) with either pro-aggregating tau (strain BR5270) or anti-aggregating tau (strain BR5271) pan-neuronal expressing transgenic Caenorhabditis elegans. The lifespan and progeny viability of the double transgenic strains were significantly decreased compared with wild type N2. In addition, co-expression of these transgenes interfered with neurotransmitter signaling pathways, caused deficits in chemotaxis associative learning, increased protein aggregation visualized by Congo red staining, and increased neuronal loss.