Endothelial cells stimulate T cell NFAT nuclear translocation in the presence of cyclosporin A: involvement of the wnt/glycogen synthase kinase-3 beta pathway.
T cells resistant to the immunosuppressive drug cyclosporin A (CsA) may be important mediators of chronic graft rejection. We previously reported that T cells activated in the presence of endothelial cells (EC) develop resistance to CsA, and initiate IL-2 secretion within 8-12 h of triggering. CsA normally blocks the phosphatase, calcineurin, thus preventing nuclear translocation of the transcription factor, NFAT. We find that in the presence but not the absence of EC, NFAT1 can be detected in the nuclei of CsA-treated T cells within 8 h of triggering, reaching a maximal level of 60% of control by 24 h. Glycogen synthase kinase-3beta (GSK-3beta), which rephosphorylates NFAT and promotes nuclear export, is inhibited by EC costimulation. GSK-3beta is a component of the wnt signaling pathway, and EC express wnt-5a and T cells express frizzled-5, a wnt-5a receptor. Wnt-5a promotes T cell NFAT nuclear accumulation in the presence of CsA, an effect mimicked by Li(+), a potent inhibitor of GSK-3beta. The protein kinase C agonist PMA dramatically synergizes with both EC and wnt-5a in stimulating T cell IL-2 synthesis, and inhibition of either protein kinase C by Ro-31-8425 or G-proteins by pertussis toxin effectively blocks the actions of wnt-5a on T cells. Finally, a secreted, dominant-negative form of frizzled-5 blocks EC-mediated CsA resistance. Thus, EC promote CsA-resistant nuclear localization of NFAT and subsequent IL-2 synthesis through a noncanonical wnt-dependent pathway.
Murphy
Lisa L Salazar
LL
Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.
Hughes
Christopher C W
CC
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D019703:Calcineurin / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology / Q000276:immunology / Q000378:metabolism*; D002478:Cells, Cultured; D018920:Coculture Techniques; D006224:Cricetinae; D016572:Cyclosporine / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004351:Drug Resistance / Q000276:immunology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D004789:Enzyme Activation / Q000276:immunology; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000502:physiology*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008969:Molecular Sequence Data; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D009842:Oligopeptides / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000201:enzymology / Q000276:immunology / Q000378:metabolism*; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051153:Wnt Proteins; D000071818:Wnt-5a Protein
D004268:DNA-Binding Proteins; D007166:Immunosuppressive Agents; D050778:NFATC Transcription Factors; C494006:NFATC2 protein, human; D009687:Nuclear Proteins; D009842:Oligopeptides; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; C085389:WNT5A protein, human; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D016572:Cyclosporine; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D011493:Protein Kinase C; D038362:Glycogen Synthase Kinase 3; D019703:Calcineurin; D019204:GTP-Binding Proteins