Nodakenin suppresses lipopolysaccharide-induced inflammatory responses in macrophage cells by inhibiting tumor necrosis factor receptor-associated factor 6 and nuclear factor-κB pathways and protects mice from lethal endotoxin shock.
Nodakenin, a coumarin isolated from the roots of Angelicae gigas, has been reported to possess neuroprotective, antiaggregatory, antibacterial, and memory-enhancing effects. In the present study, we investigated the anti-inflammatory effects of nodakenin by examining its in vitro inhibitory effects on inducible nitric-oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and proinflammatory cytokines in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages and mouse peritoneal macrophages and its in vivo effects on LPS-induced septic shock in mice. Our results indicate that nodakenin concentration-dependently inhibits iNOS and COX-2 at the protein, mRNA, and promoter binding levels, and these inhibitions cause attendant decreases in the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂). Furthermore, we found that nodakenin inhibits the production and mRNA expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β induced by LPS. Molecular data revealed that nodakenin suppressed the transcriptional activity and translocation of nuclear factor-κB (NF-κB) by inhibiting inhibitory κB-α degradation and IκB kinase-α/β phosphorylation. In addition, nodakenin was found to significantly inhibit the LPS-induced binding of transforming growth factor-β-activated kinase 1 to tumor necrosis factor receptor-associated factor 6 (TRAF6) by reducing TRAF6 ubiquitination. Pretreatment with nodakenin reduced the serum levels of NO, PGE₂, and proinflammatory cytokines and increased the survival rate of mice with LPS-induced endotoxemia. Taken together, our data suggest that nodakenin down-regulates the expression of the proinflammatory iNOS, COX-2, TNF-α, IL-6, and IL-1β genes in macrophages by interfering with the activation of TRAF6, thus preventing NF-κB activation.
Department of Pharmaceutical Biochemistry, College of Pharmacy, Kyung Hee University, Seoul, Republic of Korea.
Hong-Kun
HK
Rim
Woong
W
Cho
Sang Hyun
SH
Sung
Kyung-Tae
KT
Lee
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D003374:Coumarins / Q000494:pharmacology*; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D015232:Dinoprostone / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D004347:Drug Interactions; D005960:Glucosides / Q000494:pharmacology*; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D020672:I-kappa B Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D007249:Inflammation / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D053583:Interleukin-1beta / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012772:Shock, Septic / Q000188:drug therapy / Q000378:metabolism / Q000517:prevention & control*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D048029:TNF Receptor-Associated Factor 6 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination / Q000187:drug effects / Q000235:genetics; D000099151:MAP Kinase Kinase Kinase 7; D000093242:Interleukin-6 Inhibitors
D000893:Anti-Inflammatory Agents; D003374:Coumarins; D051546:Cyclooxygenase 2; D015232:Dinoprostone; D005960:Glucosides; D051550:I-kappa B Kinase; D020672:I-kappa B Proteins; D053583:Interleukin-1beta; D015850:Interleukin-6; D008070:Lipopolysaccharides; D020930:MAP Kinase Kinase Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D048029:TNF Receptor-Associated Factor 6; D014409:Tumor Necrosis Factor-alpha; D000099151:MAP Kinase Kinase Kinase 7; D000093242:Interleukin-6 Inhibitors; C000606205:Nfkbia protein, mouse; C496317:Nos2 protein, mouse; C077623:Ptgs2 protein, mouse; C471579:nodakenin