Upregulation of cyclooxygenase-2 by 4-nonylphenol is mediated through the cyclic amp response element activation pathway.
The organic compound nonylphenol (NP) belongs to the family of alkylphenols and is a product of industrial synthesis formed during phenol alkylation. Nonylphenol is considered to be an endocrine disruptor due to weak ability to mimic estrogen and subsequently to disrupt the natural balance of hormones in a given organism. Since the endocrine and immune systems share portions of common signaling pathways, it is conceivable that NP may also affect immune system functions. However, the influence of NP on inflammation and macrophages responsiveness to NP is unclear. Thus, the effects of NP were investigated on cyclooxygenase (COX)-2 expression in cultured macrophages. NP induced COX-2 protein and gene expression in murine macrophage RAW264.7 cells and enhanced COX-2 promoter activity and prostaglandin E(2) production. Transfection of RAW264.7 cells with hCOX-2 or various deletion and mutation promoter constructs revealed that the cyclic AMP response element (CRE) was the predominant mediator responsive to NP-induced effects. Moreover, transfection with pCRE-Luc plasmid followed by immunoblotting demonstrated that NP activated CRE sites and CRE binding protein (CREB) phosphorylation. NP also increased nuclear CREB accumulation and CREB binding to the COX-2 promoter. Phosphatidylinositol 3 (PI3)-kinase, Akt, and the mitogen-activated protein kinases (MAP kinases) p38 and JNK were also significantly activated by NP. Our data demonstrate that NP induces COX-2 expression through the PI3-kinase/Akt/MAP kinases/CRE pathway. These findings provide insight into the signal transduction pathways involved in the inflammatory responses induced by NP in macrophages.
Han
Eun Hee
EH
Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, South Korea.
Hwang
Yong Pil
YP
Kim
Hyung Gyun
HG
Park
Jin Hee
JH
Jeong
Tae Cheon
TC
Jeong
Hye Gwang
HG
D000818:Animals; D050882:CREB-Binding Protein / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D053492:Elafin / Q000378:metabolism; D052244:Endocrine Disruptors / Q000494:pharmacology*; D006801:Humans; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D051379:Mice; D010636:Phenols / Q000494:pharmacology*; D010766:Phosphorylation; D011485:Protein Binding / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D015854:Up-Regulation / Q000187:drug effects*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D053492:Elafin; D052244:Endocrine Disruptors; C506806:PI3 protein, human; D010636:Phenols; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D050882:CREB-Binding Protein; D051057:Proto-Oncogene Proteins c-akt; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; C041594:4-nonylphenol