Substance P mediates AP-1 induction in A549 cells via reactive oxygen species.
A common feature in asthma is the induction of reactive oxygen species (ROS) and the AP-1 transcription factor during the inflammatory process. AP-1 induction leads to an increased expression of pro-inflammatory cytokines. Also, higher levels of the pro-inflammatory neuropeptide substance P (SP) have been reported in bronchoalveolar-lavage fluid of asthmatics. Here, the role of SP on ROS induction and the downstream activation of AP-1 in A549 airway epithelial cells was investigated by dichloroflourescein-diacetate method and reporter gene assays. The SP-mediated AP-1 induction was dependent on extracellular calcium and ROS. The likely source of ROS are the mitochondria as rotenone inhibited AP-1 induction and the p47phox subunit of the NADPH oxidase complex, responsible for ROS generation in phagocytotic cells, was not expressed in A549 cells assayed by RT-PCR. This is consistent with results obtained from cells of murine bronchial epithelium, isolated by laser capture microdissection. In summary, this study provides evidence for an SP-mediated induction of AP-1, which may contribute to the expression of pro-inflammatory cytokines.
Springer
Jochen
J
Division of Allergy Research, Department Pediatric Pneumology and Immunology, Charité Medical School, Berlin, Germany. jochen.springer@charite.de
Pleimes
Dirk
D
Scholz
Frank R
FR
Fischer
Axel
A
D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D007834:Lasers; D042282:Microdissection; D019255:NADPH Oxidases / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013373:Substance P / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000378:metabolism*
D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; D013373:Substance P; D019255:NADPH Oxidases; D002118:Calcium