Effects of sphondin, isolated from Heracleum laciniatum, on IL-1beta-induced cyclooxygenase-2 expression in human pulmonary epithelial cells.
Recently, under large-scale screening experiments, we found that sphondin, a furanocoumarin derivative isolated from Heracleum laciniatum, possessed an inhibitory effect on IL-1beta-induced increase in the level of COX-2 protein and PGE(2) release in A549 cells. Accordingly, we examined in the present study the action mechanism of sphondin on the inhibition of IL-1beta-induced COX-2 protein expression and PGE(2) release in a human pulmonary epithelial cell line (A549). Pretreatment of cells with sphondin (10-50 microM) concentration-dependently attenuated IL-1beta-induced COX-2 protein expression and PGE(2) release. The IL-1beta-induced increase in COX-2 mRNA expression was also attenuated by sphondin (50 microM). The selective COX-2 inhibitor, NS-398 (0.01-1 microM), inhibited the activity of the COX-2 enzyme in a concentration-dependent manner, while sphondin (10-50 microM) had no effect. Sphondin (50 microM) did not affect the IL-1beta-induced activations of p44/42 MAPK, p38 MAPK, and JNK. Treatment of cells with sphondin (50 microM) or the NF-kappaB inhibitor, PDTC (50 microM) partially inhibited IL-1beta-induced degradation of IkappaB-alpha in the cytosol and translocation of p65 NF-kappaB from the cytosol to the nucleus. Furthermore, IL-1beta-induced NF-kappaB-specific DNA-protein complex formation in the nucleus was partially inhibited by sphondin (50 microM) or PDTC (50 microM). Taken together, we demonstrate that sphondin inhibits IL-1beta-induced PGE(2) release in A549 cells; this inhibition is mediated by suppressing of COX-2 expression, rather than by inhibiting COX-2 enzyme activity. The inhibitory mechanism of sphondin on IL-1beta-induced COX-2 expression may be, at least in part, through suppression of NF-kappaB activity. We conclude that sphondin may have the therapeutic potential as an anti-inflammatory drug on airway inflammation.
Yang
Ling Ling
LL
Graduate Institute of Pharmacognosy Science, Taipei Medical University, Taipei, Taiwan.
Liang
Yu Chih
YC
Chang
Chia Wen
CW
Lee
Wen Sen
WS
Kuo
Chen Tzu
CT
Wang
Ching Chiung
CC
Lee
Horng Mo
HM
Lin
Chien Huang
CH
D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism; D004586:Electrophoresis; D004789:Enzyme Activation / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000201:enzymology*; D030002:Heracleum / Q000737:chemistry*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D007527:Isoenzymes / Q000096:biosynthesis*; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D008565:Membrane Proteins; D008730:Methoxsalen / Q000031:analogs & derivatives* / Q000494:pharmacology*; D048052:Mitogen-Activated Protein Kinase 3; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000187:drug effects; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D048051:p38 Mitogen-Activated Protein Kinases
D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; C039410:sphondin; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D048052:Mitogen-Activated Protein Kinase 3; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D015232:Dinoprostone; D008730:Methoxsalen