title: Serum amyloid A (SAA) induces pentraxin 3 (PTX3) production in rheumatoid synoviocytes.
abstract: OBJECTIVE
  Pentraxin 3 (PTX3) is an acute-phase reactant that is involved in amplification of the inflammatory response and innate immunity. In the present study, we evaluated the relationship between PTX3 and serum amyloid A (SAA), another acute-phase reactant, in rheumatoid synoviocytes.
  
  
  METHODS
  PTX3 mRNA expression was examined by reverse transcription polymerase chain reaction, and PTX3 protein was measured by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  SAA induced PTX3 mRNA and PTX3 protein expression in rheumatoid synoviocytes. SAA-induced PTX3 expression was attenuated when rheumatoid synoviocytes were nucleofected with N-formyl peptide receptor ligand-1 (FPRL-1)-specific siRNA, suggesting the involvement of FPRL-1. Furthermore, SAA-induced PTX3 expression was inhibited by NF-κB or mitogen-activated protein kinase-specific inhibitors. Neither soluble TNF receptor (etanercept) nor recombinant IL-1 receptor antagonist affected PTX3 production by SAA-stimulated synoviocytes, suggesting that SAA directly induces PTX3.
  
  
  CONCLUSIONS
  Our data suggest that SAA plays a role in the proinflammatory and immune responses in rheumatoid synovium by inducing PTX3. We provide the first evidence that the acute-phase reactant SAA, which is produced systemically by hepatocytes, perpetuates the rheumatoid inflammatory processes by inducing another proinflammatory molecule, PTX3, locally in rheumatoid synovial tissues.
authors.affiliation: Department of Rheumatology, Nagasaki Medical Center, Omura, Nagasaki, 856-8562, Japan.
authors.forename: Kenshi
authors.initials: K
authors.lastname: Satomura
authors.forename: Takafumi
authors.initials: T
authors.lastname: Torigoshi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Koga
authors.forename: Yumi
authors.initials: Y
authors.lastname: Maeda
authors.forename: Yasumori
authors.initials: Y
authors.lastname: Izumi
authors.forename: Yuka
authors.initials: Y
authors.lastname: Jiuchi
authors.forename: Taiichiro
authors.initials: T
authors.lastname: Miyashita
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamasaki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawakami
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Aiba
authors.forename: Minoru
authors.initials: M
authors.lastname: Nakamura
authors.forename: Atsumasa
authors.initials: A
authors.lastname: Komori
authors.forename: Junji
authors.initials: J
authors.lastname: Sato
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ishibashi
authors.forename: Satoru
authors.initials: S
authors.lastname: Motokawa
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Migita
mesh_terms: D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D002097:C-Reactive Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D020868:Gene Silencing; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D010003:Osteoarthritis / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D044042:Receptors, Formyl Peptide / Q000235:genetics / Q000378:metabolism; D044067:Receptors, Lipoxin / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins; D000685:Serum Amyloid A Protein / Q000494:pharmacology*; D000683:Serum Amyloid P-Component / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013583:Synovial Membrane / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D014162:Transfection; D000099153:Pentraxins
chemical_list: D002097:C-Reactive Protein; D004791:Enzyme Inhibitors; D020929:Mitogen-Activated Protein Kinase Kinases; D016328:NF-kappa B; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D044042:Receptors, Formyl Peptide; D044067:Receptors, Lipoxin; D011994:Recombinant Proteins; D000685:Serum Amyloid A Protein; D000683:Serum Amyloid P-Component; D000099153:Pentraxins; C105101:FPR2 protein, human