TNF-alpha, inefficient by itself, potentiates IL-1beta-induced PGHS-2 expression in human pulmonary microvascular endothelial cells: requirement of NF-kappaB and p38 MAPK pathways.
1: Prostaglandin H synthase-2 (PGHS-2), is an inducible enzyme involved in various inflammatory responses. We established here that interleukin-1beta (IL-1beta) but not tumour necrosis factor-alpha (TNF-alpha) increased its expression in human pulmonary microvascular endothelial cells (HPMEC). However, associated with IL-1beta, TNF-alpha greatly potentiated this enzyme induction. 2: Although unable to induce PGHS-2 expression by itself, TNF-alpha promoted a similar transcription nuclear factor-kappaB (NF-kappaB) activation to IL-1beta. This effect was more pronounced when cells were co-exposed to both cytokines. HPMEC pre-treatment with MG-132, a proteasome inhibitor, prevented NF-kappaB activation as well as more distal signalling response, indicating that NF-kappaB activation is required but not sufficient for PGHS-2 expression. 3: Both IL-1beta and TNF-alpha failed to activate c-Jun NH2-terminal kinase (JNK). In addition, PD98059, a p42/44 mitogen-activated protein kinase (MAPK) phosphorylation inhibitor, did not decrease PGHS-2 expression. However, SB 203580, a p38 MAPK inhibitor, suppressed PGHS-2 induction by IL-1beta alone or combined with TNF-alpha, demonstrating that p38 MAPK but not p42/44 MAPK or JNK cascades are required for PGHS-2 up-regulation. 4: Finally, TNF-alpha, unlike IL-1beta, was unable to promote p38 MAPK phosphorylation, indicating that the failure of TNF-alpha to induce PGHS-2 expression is linked, at least in part, to its inability to activate p38 MAPK signalling pathway. Altogether, these data enhanced our understanding of PGHS-2 regulation in HPMEC and emphasize the heterogeneity of cellular responses to proinflammatory cytokines.
Said
Fatima Ait
FA
Unité de Pharmacologie Cellulaire, Unité Associée, Institut Pasteur-INSERM U 485, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France.
Werts
Catherine
C
Elalamy
Ismaïl
I
Couetil
Jean-Paul
JP
Jacquemin
Claude
C
Hatmi
Mohamed
M
D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D004268:DNA-Binding Proteins / Q000378:metabolism; D004357:Drug Synergism; D024202:Electrophoretic Mobility Shift Assay; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004790:Enzyme Induction; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology* / Q000502:physiology; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D008168:Lung / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008565:Membrane Proteins; D008833:Microcirculation; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D050796:STAT3 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology* / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases
D004268:DNA-Binding Proteins; D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D015534:Trans-Activators; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases