Abstract: Particulate matter (PM), a component of air pollution, has been epidemiologically associated
with a variety of diseases. Recent reports reveal that PM has detrimental effects on the brain. In this
study, we aimed to investigate the biological effects of ambient particles on the neurodegenerative disease Parkinson’s disease (PD). We exposed mice to coarse particles (PM10: 2.5–10 µm) for short (5 days)
and long (8 weeks) durations via intratracheal instillation. Long-term PM10 exposure exacerbated
motor impairment and dopaminergic neuron death in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
(MPTP)-induced PD mouse models. Short-term PM10 exposure resulted in both pulmonary and
systemic inflammatory responses in mice. We further investigated the mechanism underlying PM10-
induced neurotoxicity in cocultures of lung LA-4 epithelial cells and RAW264.7 macrophages. PM10
treatment elicited a dramatic increase in proinflammatory mediators in LA-4/RAW264.7 coculture.
Treating BV2 microglial cells with PM10-treated conditioned medium induced microglial activation.
Furthermore, 1-methyl-4-phenylpyridinium (MPP+
) treatment caused notable cell death in N2A
neurons cocultured with activated BV2 cells in PM10-conditioned medium. Altogether, our results
demonstrated that PM10 plays a role in the neurodegeneration associated with PD. Thus, the impact
of PM10 on neurodegeneration could be related to detrimental air pollution-induced systemic effects
on the brain.
Keywords: Parkinson’s disease; particulate matter; neuroinflammation; systemic inflammation;
microglial activation