Myeloid differentiation factor 88-dependent transcriptional regulation of cyclooxygenase-2 expression by CpG DNA: role of NF-kappaB and p38.
CpG DNA induces macrophage cyclooxgenase-2 (Cox-2) production. In this study, we have investigated a biochemical signaling pathway and transcription factors responsible for transcriptional regulation of the Cox-2 gene expression induced by CpG DNA. CpG DNA-induced Cox-2 promoter activity was completely inhibited by an endosomal acidification inhibitor (chloroquine), a TLR9 antagonist inhibitory CpG DNA, or overexpression of a dominant negative (DN) form of MyD88. In contrast, overexpression of DN-IRAK1 or DN-TRAF6 only partially inhibited CpG DNA-induced Cox-2 promoter activity and NF-kappaB activation, indicating the presence of additional signaling modulators downstream of MyD88. CpG DNA-induced Cox-2 promoter activity was substantially suppressed in cells overexpressing super-suppressive IkappaB (IkappaB-arachidonic acid), DN-p38, or DN-CREB. In addition, Cox-2 promoter-luciferase reporters with alterations in predicted cis-acting transcriptional regulatory elements revealed that C/EBP, Ets-1, NF-kappaB, and CREB-binding sites are essential for optimal Cox-2 expression in response to CpG DNA. Conclusively, these results demonstrate that endosomal DNA processing and TLR9/MyD88-dependent activation of NF-kappaB and p38 are required for transcriptional regulation of Cox-2 expression induced by CpG DNA, and suggest that interleukin-1 receptor-associated kinase and/or TRAF6 may be a diverging point for NF-kappaB activation in response to CpG DNA in RAW264.7 cells.
Yeo
Seon-Ju
SJ
Children's Foundation Research Center at Le Bonheur Children's Medical Center, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee 38103, USA.
Gravis
Demetrius
D
Yoon
Jae-Geun
JG
Yi
Ae-Kyung
AK
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism*; D001482:Base Composition; D001665:Binding Sites; D002738:Chloroquine / Q000494:pharmacology; D019976:Cloning, Organism; D051546:Cyclooxygenase 2; D004247:DNA / Q000737:chemistry / Q000235:genetics*; D017931:DNA Primers; D015226:Dinucleoside Phosphates; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000235:genetics*; D007527:Isoenzymes / Q000235:genetics*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D011971:Receptors, Immunologic / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases
D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D002738:Chloroquine; D051546:Cyclooxygenase 2; D004247:DNA; D017931:DNA Primers; D015226:Dinucleoside Phosphates; D007527:Isoenzymes; D008070:Lipopolysaccharides; D020928:Mitogen-Activated Protein Kinases; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D011451:Prostaglandin-Endoperoxide Synthases; D011971:Receptors, Immunologic; D048051:p38 Mitogen-Activated Protein Kinases; C507780:Myd88 protein, mouse; C015772:CpG dinucleotide