Impaired LPS-induced signaling in microglia overexpressing the Wiskott-Aldrich syndrome protein N-terminal domain.
Wiskott-Aldrich syndrome protein (WASP) plays important roles in TCR signaling, but its roles in signal transduction in innate immune cells have not been well characterized. As microglia are the primary immune effector cells in the brain, WASP may possibly have important roles in microglial activation, such as production of inflammatory and anti-inflammatory cytokines and neurotoxic factors. Here, we established a microglial cell line from WASP dominant-negative transgenic (Tg) mice overexpressing the N-terminal enabled/vasodilator-stimulated phosphoprotein homology 1 (EVH1) domain. WASP Tg microglia were impaired in production of inflammatory cytokines such as tumor necrosis factor-alpha, IL-6 and IL-1beta upon LPS stimulation, whereas anti-inflammatory IL-10 production was significantly enhanced. Also, LPS-induced phosphorylation of nuclear factor kappaB was reduced in WASP Tg microglia. Furthermore, WASP Tg microglia exhibited less cytotoxicity against co-cultured neurons after stimulation by LPS and IFN-gamma, with a concordant decrease in nitric oxide production. These results strongly suggest that WASP may have pivotal roles through the EVH1 domain in the LPS signaling cascade, either directly or indirectly, and modulates inflammatory immune responses in microglia.
Sato
Mitsuru
M
Transgenic Animal Research Center, National Institute of Agrobiological Sciences, 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan. sato_mitsuru@affrc.go.jp
Ogihara
Kazumasa
K
Sawahata
Ryoko
R
Sekikawa
Kenji
K
Kitani
Hiroshi
H
D000818:Animals; D001921:Brain; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis* / Q000187:drug effects; D003602:Cytotoxicity, Immunologic; D008070:Lipopolysaccharides / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D017628:Microglia / Q000166:cytology / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D051316:Wiskott-Aldrich Syndrome Protein / Q000378:metabolism*
D016207:Cytokines; D008070:Lipopolysaccharides; D016328:NF-kappa B; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D051316:Wiskott-Aldrich Syndrome Protein