Cyclosporin A inhibits activation of inducible nitric oxide synthase in C6 glioma cell line

Brain Res. 1999 Jan 16;816(1):92-8. doi: 10.1016/s0006-8993(98)01130-5.


The effects of immunosuppressant cyclosporin A (CsA) on nitric oxide (NO) production and inducible NO synthase (iNOS) mRNA expression in rat C6 glioma cell line were investigated. CsA applied simultaneously with iNOS activator IFN-gamma caused dose-dependent reduction of NO synthesis in confluent C6 cells, as determined by measuring accumulation of nitrite, an indicator of NO production, in 48 h culture supernatants. IFN-gamma-induced expression of iNOS, but not interferon regulatory factor-1 (IRF-1) mRNA was reduced in CsA-treated cells. The enzymatic activity of iNOS was not changed by CsA, since it failed to affect NO production in cells in which iNOS had already been induced with IFN-gamma and any further induction was blocked by protein synthesis inhibitor cycloheximide (CHX). FK506 was not able to mimic inhibitory effect of CsA on NO production in C6 cells, suggesting calcineurin-independent mechanism of CsA action.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcineurin Inhibitors
  • Cyclosporine / pharmacology*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Enzyme Activation / drug effects
  • Glioma / metabolism*
  • Interferon Regulatory Factor-1
  • Interferon-gamma / pharmacology
  • Nitric Oxide / antagonists & inhibitors
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase / genetics
  • Nitric Oxide Synthase / metabolism*
  • Nitric Oxide Synthase Type II
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism
  • RNA, Messenger / biosynthesis
  • Rats
  • Tacrolimus / pharmacology
  • Tumor Cells, Cultured


  • Calcineurin Inhibitors
  • DNA-Binding Proteins
  • Interferon Regulatory Factor-1
  • Irf1 protein, rat
  • Phosphoproteins
  • RNA, Messenger
  • Nitric Oxide
  • Interferon-gamma
  • Cyclosporine
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II
  • Nos2 protein, rat
  • Tacrolimus