title: Suppression of early T-cell-receptor-triggered cellular activation by the Janus kinase 3 inhibitor WHI-P-154.
abstract: BACKGROUND
  Therapeutic targeting of Janus kinase 3 (JAK3) has received particular attention, because it is associated with the common gamma signaling of cytokine receptors and thus vitally influences T-cell growth and survival. Recent evidence, however, indicates a critical role for JAK3 in signaling linked to the T-cell antigen receptor.
  
  
  METHODS
  In this study we investigated whether targeting JAK3 with a rationally designed inhibitor affects early T-cell activation events. T cells were stimulated by CD3 and CD28 cross-linking, and interleukin (IL)-2 production, activation marker expression, increase of free intracellular Ca2+ concentration, activation of the extracellular-related kinase, and nuclear translocation of transcription factors were evaluated.
  
  
  RESULTS
  We found that JAK3 inhibitor treatment dramatically impaired T-cell-receptor (TCR)-induced IL-2 production, surface activation marker expression (CD69, CD154), and homotypic T-cell aggregation. Accordingly, mRNA production of IL-2, interferon-gamma, and IL-10 was profoundly inhibited. Molecular analysis revealed that TCR-triggered phosphorylation of phospholipase C-gamma1, increase in cytoplasmic Ca2+ concentration, and activation of extracellular-related kinase were markedly reduced by the JAK3 inhibitor, resulting in substantially decreased DNA binding of nuclear factor of activated T cells and alkaline phosphatase-1 and subsequent IL-2 promoter activation. Remarkably, on TCR-independent stimulation, IL-2 production, CD69 expression, and blast formation were completely insensitive to JAK3 inhibitor treatment.
  
  
  CONCLUSIONS
  These data indicate that pharmacologic targeting of JAK3 uncouples early TCR-triggered signaling from essential downstream events, which may have important implications for the use of such compounds in T-cell-mediated disorders such as allograft rejection or graft-versus-host disease.
authors.affiliation: Institute of Immunology, Vienna, Austria.
authors.forename: Marcus D
authors.initials: MD
authors.lastname: Säemann
authors.forename: Maximilian
authors.initials: M
authors.lastname: Zeyda
authors.forename: Christos
authors.initials: C
authors.lastname: Diakos
authors.forename: Andreas
authors.initials: A
authors.lastname: Szekeres
authors.forename: Georg A
authors.initials: GA
authors.lastname: Böhmig
authors.forename: Peter
authors.initials: P
authors.lastname: Kelemen
authors.forename: Ornella
authors.initials: O
authors.lastname: Parolini
authors.forename: Hannes
authors.initials: H
authors.lastname: Stockinger
authors.forename: Eva E
authors.initials: EE
authors.lastname: Prieschl
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Stulnig
authors.forename: Thomas
authors.initials: T
authors.lastname: Baumruker
authors.forename: Gerhard J
authors.initials: GJ
authors.lastname: Zlabinger
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D002449:Cell Aggregation / Q000187:drug effects / Q000276:immunology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects / Q000276:immunology; D006084:Graft Rejection / Q000188:drug therapy / Q000276:immunology; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics; D053616:Janus Kinase 3; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects / Q000276:immunology; D014443:Tyrosine / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007376:Interleukin-2; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011799:Quinazolines; D011948:Receptors, Antigen, T-Cell; D014157:Transcription Factors; C113888:WHI P154; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C507933:JAK3 protein, human; D053616:Janus Kinase 3; D000469:Alkaline Phosphatase