A1 Refereed original research article in a scientific journal
Activation of nuclear factor of activated T cells in a cyclosporin A-resistant pathway
Authors: Ghosh P, Sica A, Cippitelli M, Subleski J, Lahesmaa R, Young HA, Rice NR
Publisher: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Publication year: 1996
Journal: Journal of Biological Chemistry
Journal name in source: JOURNAL OF BIOLOGICAL CHEMISTRY
Journal acronym: J BIOL CHEM
Volume: 271
Issue: 13
First page : 7700
Last page: 7704
Number of pages: 5
ISSN: 0021-9258
DOI: https://doi.org/10.1074/jbc.271.13.7700
Abstract
The mechanism of action of the immunosuppressive drug cyclosporin A (CsA) is the inactivation of the Ca2+/calmodulin-dependent serine-threonine phosphatase calcineurin by the drug-immunophilin complex, Inactive calcineurin is unable to activate the nuclear factor of activated T cells (NFAT), a transcription factor required for expression of the interleukin 2 (IL-2) gene. IL-2 production by CsA-treated cells is therefore dramatically reduced, We demonstrate here, however, that NFAT can be activated, and significant levels of IL-2 can be produced by the CsA-resistant CD28-signaling pathway. In transient transfection assays, both multicopy NFAT- and IL-2 promoter-beta-galactosidase reporter gene constructs could be activated by phorbol 12-myristate 13-acetate (PMA)/alpha CD28 stimulation, and this activation was resistant to CsA. Electrophoretic mobility shift assay showed the induction of a CsA-resistant NFAT complex in the nuclear extracts of peripheral blood T cells stimulated with PMA plus alpha CD28. Peripheral blood T cells stimulated with PMA/alpha CD28 produced IL-2 in the presence of CsA. Collectively, these data suggest that NFAT can be activated and IL-2 can be produced in a calcineurin independent manner.
The mechanism of action of the immunosuppressive drug cyclosporin A (CsA) is the inactivation of the Ca2+/calmodulin-dependent serine-threonine phosphatase calcineurin by the drug-immunophilin complex, Inactive calcineurin is unable to activate the nuclear factor of activated T cells (NFAT), a transcription factor required for expression of the interleukin 2 (IL-2) gene. IL-2 production by CsA-treated cells is therefore dramatically reduced, We demonstrate here, however, that NFAT can be activated, and significant levels of IL-2 can be produced by the CsA-resistant CD28-signaling pathway. In transient transfection assays, both multicopy NFAT- and IL-2 promoter-beta-galactosidase reporter gene constructs could be activated by phorbol 12-myristate 13-acetate (PMA)/alpha CD28 stimulation, and this activation was resistant to CsA. Electrophoretic mobility shift assay showed the induction of a CsA-resistant NFAT complex in the nuclear extracts of peripheral blood T cells stimulated with PMA plus alpha CD28. Peripheral blood T cells stimulated with PMA/alpha CD28 produced IL-2 in the presence of CsA. Collectively, these data suggest that NFAT can be activated and IL-2 can be produced in a calcineurin independent manner.
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