title: Tilapia hepcidin 2-3 peptide modulates lipopolysaccharide-induced cytokines and inhibits tumor necrosis factor-alpha through cyclooxygenase-2 and phosphodiesterase 4D.
abstract: The antimicrobial peptide, tilapia hepcidin (TH) 2-3, belongs to the hepcidin family, and its antibacterial function has been reported. Here, we examined the TH2-3-mediated regulation of proinflammatory cytokines in bacterial endotoxin lipopolysaccharide (LPS)-stimulated mouse macrophages. The presence of TH2-3 in LPS-stimulated cells reduced the amount of tumor necrosis factor (TNF)-α secretion. From a microarray, real-time polymerase chain reaction (PCR), and cytokine array studies, we showed down-regulation of the proinflammatory cytokines TNF-α, interleukin (IL)-1α, IL-1β, IL-6, and the prostaglandin synthesis gene, cyclooxygenase (COX)-2, by TH2-3. Studies with the COX-2-specific inhibitor, melaxicam, and with COX-2-overexpressing cells demonstrated the positive regulation of TNF-α and negative regulation of cAMP degradation-specific phosphodiesterase (PDE) 4D by COX-2. In LPS-stimulated cells, TH2-3 acts like melaxicam and down-regulates COX-2 and up-regulates PDE4D. The reduction in intracellular cAMP by TH2-3 or melaxicam in LPS-stimulated cells supports the negative regulation of PDE4D by COX-2 and TH2-3. This demonstrates that the inhibition of COX-2 is among the mechanisms through which TH2-3 controls TNF-α release. At 1 h after treatment, the presence of TH2-3 in LPS-stimulated cells had suppressed the induction of pERK1/2 and prevented the LPS-stimulated nuclear accumulation of NF-κB family proteins of p65, NF-κB2, and c-Rel. In conclusion, TH2-3 inhibits TNF-α and other proinflammatory cytokines through COX-2-, PDE4D-, and pERK1/2-dependent mechanisms.
authors.affiliation: Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, 262 Jiaushi, Taiwan.
authors.forename: Venugopal
authors.initials: V
authors.lastname: Rajanbabu
authors.forename: Chieh-Yu
authors.initials: CY
authors.lastname: Pan
authors.forename: Shang-Chun
authors.initials: SC
authors.lastname: Lee
authors.forename: Wei-Ju
authors.initials: WJ
authors.lastname: Lin
authors.forename: Ching-Chun
authors.initials: CC
authors.lastname: Lin
authors.forename: Chung-Leung
authors.initials: CL
authors.lastname: Li
authors.forename: Jyh-Yih
authors.initials: JY
authors.lastname: Chen
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D029941:Fish Proteins / Q000494:pharmacology*; D064451:Hepcidins; D053582:Interleukin-1alpha / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D052003:NF-kappa B p52 Subunit / Q000378:metabolism; D017210:Tilapia; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D023181:Antimicrobial Cationic Peptides; D029941:Fish Proteins; C579599:Hamp protein, mouse; D064451:Hepcidins; D053582:Interleukin-1alpha; D053583:Interleukin-1beta; D015850:Interleukin-6; D008070:Lipopolysaccharides; D052003:NF-kappa B p52 Subunit; C498144:Rela protein, mouse; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; C440499:lipopolysaccharide, Escherichia coli O111 B4; D000242:Cyclic AMP; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; D048052:Mitogen-Activated Protein Kinase 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; C531980:PDE4D protein, mouse