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NADPH oxidase mediates lipopolysaccharide-induced neurotoxicity and proinflammatory gene expression in activated microglia.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2004 Jan 09; Vol. 279 (2), pp. 1415-21. Date of Electronic Publication: 2003 Oct 24. - Publication Year :
- 2004
-
Abstract
- Parkinson's disease is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra. We have previously reported that lipopolysaccharide (LPS)-induced degeneration of dopaminergic neurons is mediated by the release of proinflammatory factors from activated microglia. Here, we report the pivotal role of NADPH oxidase in inflammation-mediated neurotoxicity, where the LPS-induced loss of nigral dopaminergic neurons in vivo was significantly less pronounced in NADPH oxidase-deficient (PHOX-/-) mice when compared with control (PHOX+/+) mice. Dopaminergic neurons in primary mensencephalic neuron-glia cultures from PHOX+/+ mice were significantly more sensitive to LPS-induced neurotoxicity in vitro when compared with PHOX-/- mice. Further, PHOX+/+ neuron-glia cultures chemically depleted of microglia failed to show dopaminergic neurotoxicity with the addition of LPS. Neuron-enriched cultures from both PHOX+/+ mice and PHOX-/- mice also failed to show any direct LPS-induced dopaminergic neurotoxicity. However, the addition of PHOX+/+ microglia to neuron-enriched cultures from either strain resulted in reinstatement of LPS-induced dopaminergic neurotoxicity, supporting the role of microglia as the primary source of NADPH oxidase-generated insult and neurotoxicity. Immunostaining for F4/80 in mensencephalic neuron-glia cultures revealed that PHOX-/- microglia failed to show activated morphology at 10 h, suggesting an important role of reactive oxygen species (ROS) generated from NADPH oxidase in the early activation of microglia. LPS also failed to elicit extracellular superoxide and produced low levels of intracellular ROS in microglia-enriched cultures from PHOX-/- mice. Gene expression and release of tumor necrosis factor alpha was much lower in PHOX-/- mice than in control PHOX+/+ mice. Together, these results demonstrate the dual neurotoxic functions of microglial NADPH oxidase: 1) the production of extracellular ROS that is toxic to dopamine neurons and 2) the amplification of proinflammatory gene expression and associated neurotoxicity.
- Subjects :
- Animals
Cells, Cultured
Dopamine metabolism
Dose-Response Relationship, Drug
Female
Immunohistochemistry
Inflammation
Male
Mice
Mice, Inbred C57BL
Mice, Transgenic
NADPH Oxidases metabolism
Neuroglia cytology
Neurons drug effects
Neurons metabolism
Reactive Oxygen Species
Reverse Transcriptase Polymerase Chain Reaction
Substantia Nigra metabolism
Superoxides metabolism
Time Factors
Transgenes
Tumor Necrosis Factor-alpha metabolism
Gene Expression Regulation
Lipopolysaccharides metabolism
Microglia metabolism
NADPH Oxidases physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 279
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 14578353
- Full Text :
- https://doi.org/10.1074/jbc.M307657200