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Nanometer size diesel exhaust particles are selectively toxic to dopaminergic neurons: the role of microglia, phagocytosis, and NADPH oxidase
Author(s) -
Block M. L.,
Wu X.,
Pei Z.,
Li G.,
Wang T.,
Qin L.,
Wilson B.,
Yang J.,
Hong J. S.,
Veronesi B.
Publication year - 2004
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.04-1945fje
Subject(s) - microglia , nadph oxidase , neurotoxicity , neuron , superoxide , chemistry , phagocytosis , reactive oxygen species , biology , microbiology and biotechnology , biochemistry , immunology , toxicity , inflammation , neuroscience , enzyme , organic chemistry
The contributing role of environmental factors to the development of Parkinson’s disease has become increasingly evident. We report that mesencephalic neuron‐glia cultures treated with diesel exhaust particles (DEP; 0.22 µM) (5–50 µg/ml) resulted in a dose‐dependent decrease in dopaminergic (DA) neurons, as determined by DA‐uptake assay and tyrosine‐hydroxylase immunocytochemistry (ICC). The selective toxicity of DEP for DA neurons was demonstrated by the lack of DEP effect on both GABA uptake and Neu‐N immunoreactive cell number. The critical role of microglia was demonstrated by the failure of neuron‐enriched cultures to exhibit DEP‐induced DA neurotoxicity, where DEP‐induced DA neuron death was reinstated with the addition of microglia to neuron‐enriched cultures. OX‐42 ICC staining of DEP treated neuron‐glia cultures revealed changes in microglia morphology indicative of activation. Intracellular reactive oxygen species and superoxide were produced from enriched‐microglia cultures in response to DEP. Neuron‐glia cultures from NADPH oxidase deficient (PHOX −/− ) mice were insensitive to DEP neurotoxicity when compared with control mice (PHOX +/+ ). Cytochalasin D inhibited DEP‐induced superoxide production in enriched‐microglia cultures, implying that DEP must be phagocytized by microglia to produce superoxide. Together, these in vitro data indicate that DEP selectively damages DA neurons through the phagocytic activation of microglial NADPH oxidase and consequent oxidative insult.