title: SOCS1/JAB is a negative regulator of LPS-induced macrophage activation.
abstract: Bacterial lipopolysaccharide (LPS) triggers innate immune responses through Toll-like receptor (TLR) 4. We show here that the suppressor of cytokine-signaling-1 (SOCS1/JAB) is rapidly induced by LPS and negatively regulates LPS signaling. SOCS1(+/-) mice or SOCS1(-/-) mice with interferon-gamma (IFNgamma)-deficient background were more sensitive to LPS-induced lethal effects than were wild-type littermates. LPS-induced NO(2)(-) synthesis and TNFalpha production were augmented in SOCS1(-/-) macrophages. Furthermore, LPS tolerance, a protection mechanism against endotoxin shock, was also strikingly reduced in SOCS1(-/-) cells. LPS-induced I-kappaB and p38 phosphorylation was upregulated in SOCS1(-/-) macrophages, and forced expression of SOCS1 suppressed LPS-induced NF-kappaB activation. Thus, SOCS1 directly suppresses TLR4 signaling and modulates innate immunity.
authors.affiliation: Division of Molecular and Cellular Immunology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Ichiko
authors.initials: I
authors.lastname: Kinjyo
authors.forename: Toshikatsu
authors.initials: T
authors.lastname: Hanada
authors.forename: Kyoko
authors.initials: K
authors.lastname: Inagaki-Ohara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mori
authors.forename: Daisuke
authors.initials: D
authors.lastname: Aki
authors.forename: Masanobu
authors.initials: M
authors.lastname: Ohishi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yoshida
authors.forename: Masato
authors.initials: M
authors.lastname: Kubo
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D002478:Cells, Cultured; D029721:Drosophila Proteins; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects / Q000502:physiology*; D017737:Macrophages, Peritoneal / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000502:physiology; D010766:Phosphorylation; D011956:Receptors, Cell Surface / Q000502:physiology; D012097:Repressor Proteins; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors
chemical_list: D002352:Carrier Proteins; D029721:Drosophila Proteins; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D011956:Receptors, Cell Surface; D012097:Repressor Proteins; C491590:Socs1 protein, mouse; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors