title: Increased synovial expression of IL-27 by IL-17 in rheumatoid arthritis.
abstract: OBJECTIVE
  Interleukin (IL) 17 plays an important role in synovial inflammation and bone destruction in rheumatoid arthritis (RA), while IL-27 exerts a regulatory role in T cell-mediated immune responses. Our aim was to study the influence of IL-17 on IL-27 production in RA.
  
  
  METHODS
  Following injection of IL-17 in the knee joint of CIA mice, synovium was examined for IL-17 and IL-27 expression by western blot, real-time PCR, and immunohistochemistry. IL-17 and IL-27 levels were measured by ELISA in mouse bone marrow-derived dendritic cells (BM-DCs) and in synovial fluid (SF) macrophages from RA patients.
  
  
  RESULTS
  IL-17 exacerbated disease progression in CIA mice. Histological analysis showed increased pannus formation associated with cartilage and bone erosion following injection with IL-17. The expression of IL-27 was increased in CIA mice. The expression of IL-17 and IL-27 was increased more in IL-17-injected CIA mice than in control mice. The majority of cells expressing IL-27 were co-localized with synovial macrophages. Increased expression of IL-27 by application of recombinant IL-17 was confirmed in CIA BM-DCs and in SF macrophages from RA patients.
  
  
  CONCLUSIONS
  IL-17 enhanced expression of IL-27 in synovial macrophages from RA patients and CIA mice, indicating an interaction between IL-17 and IL-27 as an autoregulatory mechanism.
authors: Department of Internal Medicine, School of Medicine, Pusan National University, Yangsan-si, Gyeongsangnam-do, Korea.
authors: Seung Hoon
authors: SH
authors: Baek
authors: Seung Geun
authors: SG
authors: Lee
authors: Young Eun
authors: YE
authors: Park
authors: Geun Tae
authors: GT
authors: Kim
authors: Chi Dae
authors: CD
authors: Kim
authors: So Youn
authors: SY
authors: Park
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001854:Bone Marrow Cells / Q000166:cytology; D003713:Dendritic Cells / Q000276:immunology; D006801:Humans; D020381:Interleukin-17 / Q000276:immunology*; D007378:Interleukins / Q000235:genetics / Q000276:immunology*; D007719:Knee Joint; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D012333:RNA, Messenger / Q000378:metabolism; D013583:Synovial Membrane / Q000276:immunology*
chemical_list: C486767:Il27 protein, mouse; D020381:Interleukin-17; D007378:Interleukins; C464565:MYDGF protein, human; D012333:RNA, Messenger