title: The JAK inhibitor CP-690,550 (tofacitinib) inhibits TNF-induced chemokine expression in fibroblast-like synoviocytes: autocrine role of type I interferon.
abstract: OBJECTIVE
  The objective of this study was to investigate the effect of the novel Janus kinase inhibitor CP-690,550 in fibroblast-like synoviocytes (FLSs) from patients with rheumatoid arthritis (RA).
  
  
  METHODS
  RA FLSs were isolated from tissue obtained by arthroplasty, cultured and serum-starved 48 h prior to stimulation. Messenger RNA and protein levels were determined by quantitative PCR and ELISA or multiplex bead assay, respectively. Phosphorylation of STAT (signal transducers and activators of transcription) proteins was determined by western blot.
  
  
  RESULTS
  Interleukin-6-induced phosphorylation of STAT1 and STAT3 was inhibited by CP-690,550 with IC(50) values of 23 and 77 nM, respectively. Unexpectedly, although tumour necrosis factor (TNF) did not induce immediate phosphorylation of either STAT, CP-690,550 inhibited TNF-induced expression of several chemokines (IP-10, RANTES and MCP1) at the messenger RNA and protein levels. Chemokine expression was inhibited by cycloheximide, implying a need for de novo protein synthesis, and cycloheximide abolished the effect of CP-690,550 (tofacitinib). TNF induced early interferon (IFN) β expression and STAT1 phosphorylation beginning at 3 h, which was blocked by CP-690,550. The dependence of TNF-induced chemokine expression on type I IFN was confirmed in FLSs from mice lacking type I IFN receptors (IFNARs) and in RA FLSs using an IFNAR blocking antibody.
  
  
  CONCLUSIONS
  The Janus kinase/STAT pathway in FLS is indirectly activated by TNF through autocrine expression of type I IFN, resulting in IFNAR engagement and production of T cell chemokines. These findings illuminate a novel role of CP-690,550 in the treatment of RA: the reduction of chemokine synthesis by FLS, thereby limiting recruitment of T cells and other infiltrating leucocytes.
authors: Division of Rheumatology, Allergy and Immunology, University of California at San Diego School of Medicine, La Jolla, California 92093-0656, USA.
authors: Sanna
authors: S
authors: Rosengren
authors: Maripat
authors: M
authors: Corr
authors: Gary S
authors: GS
authors: Firestein
authors: David L
authors: DL
authors: Boyle
mesh_terms: D000818:Animals; D018501:Antirheumatic Agents / Q000494:pharmacology*; D001172:Arthritis, Rheumatoid / Q000378:metabolism / Q000473:pathology*; D019898:Autocrine Communication / Q000187:drug effects; D002478:Cells, Cultured; D018925:Chemokines / Q000096:biosynthesis; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005347:Fibroblasts / Q000187:drug effects*; D006801:Humans; D007370:Interferon Type I / Q000502:physiology; D015850:Interleukin-6 / Q000494:pharmacology; D053616:Janus Kinase 3 / Q000037:antagonists & inhibitors*; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D010880:Piperidines; D011743:Pyrimidines / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology*; D050794:STAT1 Transcription Factor / Q000037:antagonists & inhibitors / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors / Q000378:metabolism; D013583:Synovial Membrane / Q000187:drug effects* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000093242:Interleukin-6 Inhibitors
chemical_list: D018501:Antirheumatic Agents; D018925:Chemokines; D007370:Interferon Type I; D015850:Interleukin-6; D053616:Janus Kinase 3; D010880:Piperidines; D011743:Pyrimidines; D011758:Pyrroles; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D014409:Tumor Necrosis Factor-alpha; D000093242:Interleukin-6 Inhibitors; C494079:STAT1 protein, human; C494086:STAT3 protein, human; C479163:tofacitinib