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ID 48598
file
creator
Itoh, Kouichi
abstract
Microglia are activated quickly in response to external pathogens or cell debris and clear these substances via the inflammatory response. However, excessive activation of microglia can be harmful to host cells due to the increased production of reactive oxygen species and proinflammatory cytokines. Superoxide dismutase 2 (SOD2) is reportedly induced under various inflammatory conditions in the central nervous system. We herein demonstrated that activated microglia strongly express SOD2 and examined the role of SOD2, focusing on regulation of the microglial activity and the susceptibility of microglia to oxidative stress. When rat primary microglia were treated with LPS, poly(I:C), peptidoglycan, or CpG oligodeoxynucleotide, respectively, the mRNA and protein levels of SOD2 largely increased. However, an increased expression of SOD2 was not detected in the primary neurons or astrocytes, indicating that SOD2 is specifically induced in microglia under inflammatory conditions. The activated microglia showed high tolerance to oxidative stress, whereas SOD2 knockdown conferred vulnerability to oxidative stress. Interestingly, the production of proinflammatory cytokines was increased in the activated microglia treated with SOD2 siRNA compared with that observed in the control siRNA-treated cells. Pretreatment with NADPH oxidase inhibitors, diphenylene iodonium and apocynin, decreased in not only reactive oxygen species generation but also the proinflammatory cytokine expression. Notably, SOD2 knockdown largely potentiated the nuclear factor κB activity in the activated microglia. Taken together, increased SOD2 conferred tolerance to oxidative stress in the microglia and decreased proinflammatory cytokine production by attenuating the nuclear factor κB activity. Therefore, SOD2 might regulate neuroinflammation by controlling the microglial activities.
description
This work was supported in part by KAKENHI Grants 26740024, 30291149, and 22310041 from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (to Y. I., K. I., and T. Y.); a grant from the Fujii Foundation (to Y. I.); and a grant from the Hiroshima University Education and Research Support Foundation (to Y. I.).
journal title
Journal of Biological Chemistry
volume
Volume 290
issue
Issue 37
start page
22805
end page
22817
date of issued
2015-09-11
publisher
The American Society for Biochemistry and Molecular Biology, Inc.
issn
0021-9258
1083-351X
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
This research was originally published in the Journal of Biological Chemistry. Yasuhiro Ishihara, Takuya Takemoto, Kouichi Itoh, Atsuhiko Ishida, and Takeshi Yamazaki. Dual Role of Superoxide Dismutase 2 Induced in Activated Microglia: OXIDATIVE STRESS TOLERANCE AND CONVERGENCE OF INFLAMMATORY RESPONSES. J. Biol. Chem. 2015; 290(37):22805-22817. © the American Society for Biochemistry and Molecular Biology.
relation url
department
Graduate School of Integrated Arts and Sciences