Cytosolic phospholipase A2 Group IValpha but not secreted phospholipase A2 Group IIA, V, or X induces interleukin-8 and cyclooxygenase-2 gene and protein expression through peroxisome proliferator-activated receptors gamma 1 and 2 in human lung cells.
It has been reported that interleukin-8 (IL-8) and cyclooxygenase-2 (COX-2) expression is regulated by peroxisome proliferator-activated receptor (PPAR)-gamma synthetic ligands. We have shown previously that cytosolic phospholipase A2 (cPLA2) is able to activate gene expression through PPAR-gamma response elements (Pawliczak, R., Han, C., Huang, X. L., Demetris, A. J., Shelhamer, J. H., and Wu, T. (2002) J. Biol. Chem. 277, 33153-33163). In this study we investigated the influence of cPLA2 and secreted phospholipase A2 (sPLA2) Group IIA, Group V, and Group X on IL-8 and COX-2 expression in human lung epithelial cells (A549 cells). We also studied the results of cPLA2 activation by epidermal growth factor (EGF) and calcium ionophore (A23187) on IL-8 and COX-2 reporter gene activity, mRNA level, and protein synthesis. cPLA2 overexpression and activation increased both IL-8 and COX-2 reporter gene activity. Overexpression and activation of Group IIA, Group V, or Group X sPLA2s did not increase IL-8 and COX-2 reporter gene activity. Methyl arachidonyl fluorophosphate, a cPLA2 inhibitor, inhibited the effect of A23187 and of EGF on both IL-8 and COX-2 reporter gene activity, steady state levels of IL-8 and COX-2 mRNA, and IL-8 and COX-2 protein expression. Small inhibitory RNAs directed against PPAR-gamma1 and -gamma2 blunted the effect of A23187 and of EGF on IL-8 and COX-2 protein expression. Moreover small inhibitory RNAs directed against cPLA2 decreased the effect of A23187 and EGF on IL-8 and COX-2 protein expression. These results demonstrate that cPLA2 has an influence on IL-8 and COX 2 gene and protein expression at least in part through PPAR-gamma.
Critical Care Medicine Department, National Institutes of Health, Bethesda, Maryland 20892, USA.
Rafal
R
Pawliczak
Carolea
C
Logun
Patricia
P
Madara
Marion
M
Lawrence
Grzegorz
G
Woszczek
Anetta
A
Ptasinska
Marek L
ML
Kowalski
Tong
T
Wu
James H
JH
Shelhamer
D016718:Arachidonic Acid / Q000378:metabolism; D000001:Calcimycin / Q000494:pharmacology; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D051546:Cyclooxygenase 2; D003600:Cytosol / Q000201:enzymology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D054501:Group II Phospholipases A2; D054513:Group IV Phospholipases A2; D054505:Group V Phospholipases A2; D054509:Group X Phospholipases A2; D006801:Humans; D015151:Immunoblotting; D016209:Interleukin-8 / Q000378:metabolism*; D007476:Ionophores / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism*; D008168:Lung / Q000378:metabolism*; D008565:Membrane Proteins; D047495:PPAR gamma / Q000378:metabolism*; D010740:Phospholipases / Q000378:metabolism; D010741:Phospholipases A / Q000502:physiology*; D054467:Phospholipases A2; D010957:Plasmids / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014162:Transfection
D016209:Interleukin-8; D007476:Ionophores; D007527:Isoenzymes; D008565:Membrane Proteins; D047495:PPAR gamma; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016718:Arachidonic Acid; D000001:Calcimycin; D004815:Epidermal Growth Factor; D012313:RNA; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D010740:Phospholipases; D010741:Phospholipases A; D054501:Group II Phospholipases A2; D054513:Group IV Phospholipases A2; D054505:Group V Phospholipases A2; D054509:Group X Phospholipases A2; C516365:PLA2G10 protein, human; C516389:PLA2G4A protein, human; C516299:PLA2G5 protein, human; D054467:Phospholipases A2