Tire components, age and temperature accelerate neurodegeneration in C. elegans models of Alzheimer's and Parkinson's disease

Abstract

Increasingly, traffic-related air pollution is linked with Alzheimer's disease, Parkinson's disease and other neurodegenerative conditions. The molecular pathways underlying the epidemiologic observations are unknown. In this study, models of neurodegenerative disorders in the nematode Caenorhabditis elegans were used to investigate effects of the tire wear component nano silica. Life span-resolved exposition of reporter strain GRU102 that expresses the Alzheimer's peptide amyloid beta_1-42 with silica nanoparticles significantly reduced locomotory fitness in middle-aged nematodes. A specific vulnerability of 10-day-old nematodes was identified in GRU102 cultivated at ambient temperatures of 15 and 20 °C. Reduction of locomotory fitness was corroborated in the Parkinson's disease model BZ555. Nano silica from different sources, including genuine tire components, accelerated the neurodegeneration of dopaminergic neurons in BZ555 nematodes. Dendritic beading was observed in single PDE neurons along the lateral side of the posterior body. In both, the Alzheimer's disease model GRU102 and the Parkinson's disease model BZ555 increased age and the non-chemical exposome factor temperature aggravated nano silica-induced neurodegeneration. Middle-aged cohorts were defined as the most vulnerable age-group. The results suggest C. elegans disease models as a platform to elucidate the relationships between neurodegeneration, age and the environmental factor ambient temperature after exposition with defined components of non-exhaust emissions or sampled urban aerosols.

Keywords: Air pollution; Amyloid disease; Dopaminergic neurons; Nanoparticles; Non-exhaust emissions; Tire wear.