The Sound of Evolution
Cyclosporine
Mechanism of action:
Cyclosporine is an immunosuppressant and a cyclic polypeptide originally discovered from Tolypocladium inflatum. After entering the cell, cyclosporine binds to cyclophilin in the cytoplasm to form a complex. This complex inhibits the activity of calcineurin. Calcineurin normally dephosphorylates NFAT (nuclear factor of activated T cells), allowing NFAT to enter the nucleus and promote the transcription of IL-2, IFN-γ, and other genes involved in T cell activation. When calcineurin is inhibited by cyclosporine, the expression of IL-2 and related genes decreases, thereby suppressing T cell proliferation and activation.
Reference(s):
1. Lichtiger S et al. (1994). Cyclosporine in severe ulcerative colitis refractory to steroid therapy. N Engl J Med.
2. Forsythe P et al. (2014). Ciclosporin 10 years on: indications and efficacy. Vet Rec.