Cigarette smoke extract induces cytosolic phospholipase A2 expression via NADPH  oxidase, MAPKs, AP-1, and NF-kappaB in human tracheal smooth muscle cells.
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-kappaB (helenalin) and AP-1 (curcumin). Moreover, promoter assays revealed that increases of cPLA2, NF-kappaB, 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-kappaB and AP-1 activities which were essential for CSE-induced cPLA2 gene expression.
Cheng
Shin-Ei
SE
Department of Pharmacology, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan.
Luo
Shue-Fen
SF
Jou
Mei-Jie
MJ
Lin
Chih-Chung
CC
Kou
Yu Ru
YR
Lee
I-Ta
IT
Hsieh
Hsi-Lung
HL
Yang
Chuen-Mao
CM
D000098:Acetophenones / Q000494:pharmacology; D000111:Acetylcysteine / Q000494:pharmacology; D002070:Butadienes / Q000494:pharmacology; D002478:Cells, Cultured; D003474:Curcumin / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D009570:Nitriles / Q000494:pharmacology; D009861:Onium Compounds / Q000494:pharmacology; D018384:Oxidative Stress; D054467:Phospholipases A2 / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D012717:Sesquiterpenes / Q000494:pharmacology; D045789:Sesquiterpenes, Guaiane; D012907:Smoking / Q000009:adverse effects*; D014132:Trachea / Q000378:metabolism / Q000473:pathology; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors; D015533:Transcriptional Activation; D048051:p38 Mitogen-Activated Protein Kinases
D000098:Acetophenones; D002070:Butadienes; D016328:NF-kappa B; D009570:Nitriles; D009861:Onium Compounds; D034741:RNA, Small Interfering; D012717:Sesquiterpenes; D045789:Sesquiterpenes, Guaiane; D018808:Transcription Factor AP-1; C113580:U 0126; C001329:helenalin; C007517:diphenyleneiodonium; C056165:acetovanillone; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D048051:p38 Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; D054467:Phospholipases A2; D003474:Curcumin; D000111:Acetylcysteine