title: Critical roles of the WASP N-terminal domain and Btk in LPS-induced inflammatory response in macrophages.
abstract: While Wiskott-Aldrich syndrome protein (WASP) plays critical roles in TCR signaling as an adaptor molecule, how it transduces innate immune signals remains to be elucidated. To investigate the roles of WASP in innate immune cells, we established bone marrow-derived macrophage (BMDM) cell lines from WASP15 transgenic (Tg) mice overexpressing the WASP N-terminal region (exons 1-5). Upon LPS stimulation, WASP15 Tg BMDM cell lines produce lower levels of inflammatory cytokines, such as TNF-α, IL-6, and IL-12p40 than the wild-type BMDM cell line. In addition, the production of nitric oxide by WASP15 Tg BMDM cells in response to LPS and IFN-γ was significantly impaired. Furthermore, we uncovered that the WASP N-terminal domain associates with the Src homology (SH) 3 domain of Bruton's tyrosine kinase (Btk). Overexpression of the WASP N-terminal domain diminishes the extent of tyrosine phosphorylation of endogenous WASP in WASP15 Tg BMDM cells, possibly by interfering with the specific binding between endogenous WASP and Btk during LPS signaling. These observations strongly suggest that the interaction between WASP N-terminal domain and Btk plays important roles in the LPS signaling cascade in innate immunity.
authors.affiliation: Animal Immune and Cell Biology Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Chisato
authors.initials: C
authors.lastname: Sakuma
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Sato
authors.forename: Takato
authors.initials: T
authors.lastname: Takenouchi
authors.forename: Joe
authors.initials: J
authors.lastname: Chiba
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitani
mesh_terms: D000077329:Agammaglobulinaemia Tyrosine Kinase; D000818:Animals; D001854:Bone Marrow Cells / Q000473:pathology; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D003598:Cytoskeletal Proteins; D004789:Enzyme Activation / Q000187:drug effects; D007249:Inflammation / Q000201:enzymology / Q000473:pathology*; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000378:metabolism*; D017472:Receptors, Interleukin-1 / Q000378:metabolism; D013329:Structure-Activity Relationship; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D051316:Wiskott-Aldrich Syndrome Protein / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D017472:Receptors, Interleukin-1; C499045:TIRAP protein, mouse; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; C491671:Waspip protein, mouse; D051316:Wiskott-Aldrich Syndrome Protein; D019000:Phosphotyrosine; D009569:Nitric Oxide; D007371:Interferon-gamma; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625951:Btk protein, mouse