title: Induction of cyclooxygenase-2 by bovine type I collagen in macrophages via C/EBP and CREB activation by multiple cell signaling pathways.
abstract: Bovine type I collagen (Col-I) is utilized for medical purposes such as cosmetic surgery and wrinkle removal. Cyclooxygenase-2 (COX-2) plays roles in pathophysiological processes including inflammation and tumorigenesis. This study examines the effects of Col-I on the COX-2 expression and the signaling pathways in macrophages. Col-I increased the levels of COX-2 protein and mRNA in serum-stimulated Raw264.7 cells in a time- and concentration-dependent manner. Treatment of cells with Col-I increased CCAAT/enhancer binding protein (C/EBP) DNA binding. Antibody supershift experiments revealed that C/EBP DNA binding activity induced by Col-I depended largely on C/EBPbeta and C/EBPdelta. Immunocytochemistry showed that Col-I induced nuclear translocation of C/EBPbeta and C/EBPdelta, whose activation contributes to COX-2 induction. Overexpression of the dominant-negative mutant form of C/EBP abolished COX-2 induction by Col-I. Col-I also increased cyclic-AMP response element binding protein (CREB) binding to DNA. Inhibition of focal adhesion kinase (FAK) or downstream phosphoinositide 3-kinase and p70S6 kinase by specific chemical inhibitors prevented COX-2 induction by Col-I, and C/EBP and CREB from binding to their consensus DNA oligonucleotides. Experiments using chemical inhibitors or dominant-negative mutant vectors showed that the mitogen-activated protein (MAP) kinase pathways including p38-kinase and extracellular signal-regulated kinase (ERK1/2), but not c-Jun N-terminal kinase (JNK1), simultaneously regulated COX-2 induction by Col-I. This was in agreement with inhibition of Col-I-inducible C/EBP and CREB DNA binding by concomitant treatment with SB203580 and PD98059. These results provide evidence that Col-I induces COX-2 in serum-stimulated macrophages and that the multiple cell signaling pathways involving Src-focal adhesion kinase, phosphoinositide 3-kinase, and MAP kinases regulate COX-2 induction by Col-I via C/EBP and CREB activation.
authors.affiliation: National Research Laboratory, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Min Kyung
authors.initials: MK
authors.lastname: Cho
authors.forename: Yang Hee
authors.initials: YH
authors.lastname: Cho
authors.forename: Gum Hwa
authors.initials: GH
authors.lastname: Lee
authors.forename: Sang Geon
authors.initials: SG
authors.lastname: Kim
mesh_terms: D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism*; D002417:Cattle; D024042:Collagen Type I / Q000494:pharmacology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D051546:Cyclooxygenase 2; D004790:Enzyme Induction / Q000187:drug effects; D007527:Isoenzymes / Q000096:biosynthesis*; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D024042:Collagen Type I; D017362:Cyclic AMP Response Element-Binding Protein; D007527:Isoenzymes; D016328:NF-kappa B; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D019869:Phosphatidylinositol 3-Kinases; D020928:Mitogen-Activated Protein Kinases