title: Role of MAPK in the regulation of double-stranded RNA- and encephalomyocarditis virus-induced cyclooxygenase-2 expression by macrophages.
abstract: In response to virus infection or treatment with dsRNA, macrophages express the inducible form of cyclooxygenase-2 (COX-2) and produce proinflammatory prostaglandins. Recently, we have shown that NF-kappaB is required for encephalomyocarditis virus (EMCV)- and dsRNA-stimulated COX-2 expression in mouse macrophages. The dsRNA-dependent protein kinase R is not required for EMCV-stimulated COX-2 expression, suggesting the presence of protein kinase R-independent pathways in the regulation of this antiviral gene. In this study, the role of MAPK in the regulation of macrophage expression of cyclooxygenase-2 (COX)-2 in response to EMCV infection was examined. Treatment of mouse macrophages or RAW-264.7 cells with dsRNA or infection with EMCV stimulates the rapid activation of the MAPKs p38, JNK, and ERK. Inhibition of p38 and JNK activity results in attenuation while ERK inhibition does not modulate dsRNA- and EMCV-induced COX-2 expression and PGE2 production by macrophages. JNK and p38 appear to selectively regulate COX-2 expression, as inhibition of either kinase fails to prevent dsRNA- or EMCV-stimulated inducible NO synthase expression by macrophages. Using macrophages isolated from TLR3-deficient mice, we show that p38 and JNK activation and COX-2 expression in response to EMCV or poly(IC) does not require the presence the dsRNA receptor TLR3. These findings support a role for p38 and JNK in the selective regulation of COX-2 expression by macrophages in response to virus infection.
authors.affiliation: Edward A. Doisy Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Steer
authors.forename: Jason M
authors.initials: JM
authors.lastname: Moran
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Christmann
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Maggi
authors.forename: John A
authors.initials: JA
authors.lastname: Corbett
mesh_terms: D000818:Animals; D018188:Cardiovirus Infections / Q000235:genetics* / Q000378:metabolism* / Q000821:virology; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D015232:Dinoprostone / Q000096:biosynthesis; D004686:Encephalomyocarditis virus / Q000502:physiology*; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D020935:MAP Kinase Signaling System; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology*; D051379:Mice; D018345:Mice, Knockout; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010766:Phosphorylation; D011070:Poly I-C / Q000494:pharmacology; D012330:RNA, Double-Stranded / Q000235:genetics; D051196:Toll-Like Receptor 3 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism
chemical_list: D012330:RNA, Double-Stranded; D051196:Toll-Like Receptor 3; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D015232:Dinoprostone; D011070:Poly I-C