Cigarette smoke extract induces cytosolic phospholipase A2 expression via NADPH oxidase, MAPKs, AP-1, and NF-κB in human tracheal smooth muscle cells

Shin Ei Cheng, Shue Fen Luo, Mei Jie Jou, Chih Chung Lin, Yu Ru Kou, I-Ta Lee, Hsi Lung Hsieh, Chuen Mao Yang

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Up-regulation of cytosolic phospholipase A2 (cPLA2) by cigarette smoke extract (CSE) may play a critical role in airway inflammatory diseases. However, the mechanisms underlying CSE-induced cPLA2 expression in human tracheal smooth muscle cells (HTSMCs) remain unknown. CSE induced cPLA2 protein and mRNA expression, and ROS generation was attenuated by pretreatment with a reactive oxygen species (ROS) scavenger (N-acetylcysteine), or inhibitors of NADPH oxidase (diphenyleneiodonium chloride, apocynin) and transfection with p47phox siRNA, suggesting that CSE-induced cPLA2 expression was mediated through NADPH oxidase activation and ROS production in HTSMCs. Furthermore, CSE-induced cPLA2 expression was attenuated by pretreatment with the inhibitors of MEK1/2 (U0126), p38 MAPK (SB202190), and JNK (SP600125), which were further confirmed by transfection with siRNAs of JNK1, p42, and p38 to down-regulate the expression of respective proteins and reduce cPLA2 expression. Induction of cPLA2 by CSE was attenuated by selective inhibitors of NF-κB (helenalin) and AP-1 (curcumin). Moreover, promoter assays revealed that increases of cPLA2, NF-κB, and AP-1 luciferase activities stimulated by CSE were attenuated by these inhibitors. These results suggest that in HTSMCs, CSE induced NADPH oxidase activation leading to phosphorylation of p42/p44 MAPK, p38 MAPK, and JNK. These reactions induced nuclear transcription NF-κB and AP-1 activities which were essential for CSE-induced cPLA2 gene expression.

Original languageEnglish
Pages (from-to)948-960
Number of pages13
JournalFree Radical Biology and Medicine
Volume46
Issue number7
DOIs
Publication statusPublished - Apr 1 2009
Externally publishedYes

Keywords

  • Cigarette smoke extract
  • Cytosolic phospholipase A
  • Human tracheal smooth muscle cells
  • MAPKs
  • Reactive oxygen apecies

ASJC Scopus subject areas

  • Biochemistry
  • Physiology (medical)

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