title: Streptococcus pneumoniae induced c-Jun-N-terminal kinase- and AP-1 -dependent IL-8 release by lung epithelial BEAS-2B cells.
abstract: BACKGROUND
  Although pneumococcal pneumonia is one of the most common causes of death due to infectious diseases, little is known about pneumococci-lung cell interaction. Herein we tested the hypothesis that pneumococci activated pulmonary epithelial cell cytokine release by c-Jun-NH2-terminal kinase (JNK) METHODS: Human bronchial epithelial cells (BEAS-2B) or epithelial HEK293 cells were infected with S. pneumoniae R6x and cytokine induction was measured by RT-PCR, ELISA and Bioplex assay. JNK-phosphorylation was detected by Western blot and nuclear signaling was assessed by electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP). JNK was modulated by the small molecule inhibitor SP600125 and AP1 by transfection of a dominant negative mutant.
  
  
  RESULTS
  S. pneumoniae induced the release of distinct CC and CXC, as well as Th1 and Th2 cytokines and growth factors by human lung epithelial cell line BEAS-2B. Furthermore, pneumococci infection resulted in JNK phosphorylation in BEAS-2B cells. Inhibition of JNK by small molecule inhibitor SP600125 reduced pneumococci-induced IL-8 mRNA expression and release of IL-8 and IL-6. One regulator of the il8 promoter is JNK-phosphorylated activator protein 1 (AP-1). We showed that S. pneumoniae time-dependently induced DNA binding of AP-1 and its phosphorylated subunit c-Jun with a maximum at 3 to 5 h after infection. Recruitment of Ser63/73-phosphorylated c-Jun and RNA polymerase II to the endogenous il8 promoter was found 2 h after S. pneumoniae infection by chromatin immunoprecipitation. AP-1 repressor A-Fos reduced IL-8 release by TLR2-overexpressing HEK293 cells induced by pneumococci but not by TNFalpha. Antisense-constructs targeting the AP-1 subunits Fra1 and Fra2 had no inhibitory effect on pneumococci-induced IL-8 release.
  
  
  CONCLUSIONS
  S. pneumoniae-induced IL-8 expression by human epithelial BEAS-2B cells depended on activation of JNK and recruitment of phosphorylated c-Jun to the il8 promoter.
authors.affiliation: Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité--Universitätsmedizin Berlin, 13353 Berlin, Germany. Bernd.Schmeck@charite.de
authors.forename: Bernd
authors.initials: B
authors.lastname: Schmeck
authors.forename: Kerstin
authors.initials: K
authors.lastname: Moog
authors.forename: Janine
authors.initials: J
authors.lastname: Zahlten
authors.forename: Vincent
authors.initials: V
authors.lastname: van Laak
authors.forename: Philippe Dje
authors.initials: PD
authors.lastname: N'Guessan
authors.forename: Bastian
authors.initials: B
authors.lastname: Opitz
authors.forename: Simone
authors.initials: S
authors.lastname: Rosseau
authors.forename: Norbert
authors.initials: N
authors.lastname: Suttorp
authors.forename: Stefan
authors.initials: S
authors.lastname: Hippenstiel
mesh_terms: D000873:Anthracenes / Q000494:pharmacology; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008168:Lung / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D013296:Streptococcus pneumoniae; D018808:Transcription Factor AP-1 / Q000378:metabolism*
chemical_list: D000873:Anthracenes; D016209:Interleukin-8; D047428:Protein Kinase Inhibitors; D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1; C432165:pyrazolanthrone; D004247:DNA; D048031:JNK Mitogen-Activated Protein Kinases