title: Spred-2 deficiency exacerbates lipopolysaccharide-induced acute lung inflammation in mice.
abstract: BACKGROUND
  Acute respiratory distress syndrome (ARDS) is a severe and life-threatening acute lung injury (ALI) that is caused by noxious stimuli and pathogens. ALI is characterized by marked acute inflammation with elevated alveolar cytokine levels. Mitogen-activated protein kinase (MAPK) pathways are involved in cytokine production, but the mechanisms that regulate these pathways remain poorly characterized. Here, we focused on the role of Sprouty-related EVH1-domain-containing protein (Spred)-2, a negative regulator of the Ras-Raf-extracellular signal-regulated kinase (ERK)-MAPK pathway, in lipopolysaccharide (LPS)-induced acute lung inflammation.
  
  
  METHODS
  Wild-type (WT) mice and Spred-2(-/-) mice were exposed to intratracheal LPS (50 µg in 50 µL PBS) to induce pulmonary inflammation. After LPS-injection, the lungs were harvested to assess leukocyte infiltration, cytokine and chemokine production, ERK-MAPK activation and immunopathology. For ex vivo experiments, alveolar macrophages were harvested from untreated WT and Spred-2(-/-) mice and stimulated with LPS. In in vitro experiments, specific knock down of Spred-2 by siRNA or overexpression of Spred-2 by transfection with a plasmid encoding the Spred-2 sense sequence was introduced into murine RAW264.7 macrophage cells or MLE-12 lung epithelial cells.
  
  
  RESULTS
  LPS-induced acute lung inflammation was significantly exacerbated in Spred-2(-/-) mice compared with WT mice, as indicated by the numbers of infiltrating leukocytes, levels of alveolar TNF-α, CXCL2 and CCL2 in a later phase, and lung pathology. U0126, a selective MEK/ERK inhibitor, reduced the augmented LPS-induced inflammation in Spred-2(-/-) mice. Specific knock down of Spred-2 augmented LPS-induced cytokine and chemokine responses in RAW264.7 cells and MLE-12 cells, whereas Spred-2 overexpression decreased this response in RAW264.7 cells.
  
  
  CONCLUSIONS
  The ERK-MAPK pathway is involved in LPS-induced acute lung inflammation. Spred-2 controls the development of LPS-induced lung inflammation by negatively regulating the ERK-MAPK pathway. Thus, Spred-2 may represent a therapeutic target for the treatment of ALI.
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Ito
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Fushimi
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Sakuma
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Itakura
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Ryojiro
authors.initials: R
authors.lastname: Kimura
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Miwa
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Mino
authors.affiliation: Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshimura
authors.affiliation: Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Matsukawa
mesh_terms: D000208:Acute Disease; D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D002460:Cell Line; D018932:Chemokine CCL2 / Q000378:metabolism; D054426:Chemokine CXCL2 / Q000378:metabolism; D018450:Disease Progression; D004789:Enzyme Activation / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D008070:Lipopolysaccharides; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009570:Nitriles / Q000494:pharmacology; D011014:Pneumonia / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D012097:Repressor Proteins / Q000172:deficiency* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D002070:Butadienes; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D054426:Chemokine CXCL2; D008070:Lipopolysaccharides; D009570:Nitriles; D012097:Repressor Proteins; C433764:Spred2 protein, mouse; D014409:Tumor Necrosis Factor-alpha; C113580:U 0126; D048049:Extracellular Signal-Regulated MAP Kinases