Pier G. Ferrini

CGP 47969A: A novel inhibitor of the synthesis of inflammatory cytokines

CGP 47969A is a novel piperazine derivative that inhibits the synthesis of inflammatory cytokines, such as interleukin-1α (IL-1), IL-1β and tumor necrosis factor α (TNF), in human monocytes stimulated with lipopolysaccharide (LPS), zymosan or IL-1 itself. IC50 values are in the range of 0.3–5 μmol/l. CGP 47969A does not inhibit total protein or RNA synthesis indicating selectivity for cytokine inhibition. CGP 47969A exerts its inhibitory effect at a post-transcriptional level, most probably by reducing translational efficiency of IL-β mRNA, as steady-state levels of IL-1β mRNA are not inhibited while the primary translation product, the 31 kD IL-1β precursor molecule, is dose-dependently inhibited by CGP 47969A. The compound is devoid of cyclooxygenase and phospholipase A2 inhibitory activity but efficiently inhibits the generation of PGE2 and LTC4 in zymosanstimulated mouse macrophages with an IC50 of 1.2 and 0.6 μmol/l, respectively. Antagonism of IL-1 and/or TNF is thought to have a beneficial effect on the course of inflammatory diseases. CGP 47969A may therefore represent a mechanistically new approach to the treatment of such diseases.

Effects of the cytokine synthesis inhibitor CGP 47969A on nitric oxide production by lipopolysaccharide-stimulated J774A.1 macrophages

CGP 47969A is a novel inhibitor of the biosynthesis of interleukin-1 and other cytokines, being developed as an anti-arthritic. The effect of the compound on lipopolysaccharide (LPS; 1 μg/ml) stimulated nitric oxide (NO) production by the mouse macrophage cell line, J774A.1, was examined in the present study. CGP 47969A inhibited NO production in a concentration-dependent fashion (0.1–10 μM; IC50=2 μM) in a 24 h assay. Dexamethasone (Dex), which inhibits cytokine and inducible nitric oxide synthase (iNOS) gene transcription, andN-methyl arginine (NMA), a substrate analogue inhibitor of NOS activity, also inhibited NO production in this assay system with IC50 values of approximately 5 nM and 100 μM, respectively. When iNOS expression was induced by LPS for 24 h, CGP 47969A and Dex did not inhibit NO production, whereas NMA retained activity (IC50=40 μM). In time course experiments, CGP 47969A (10 μM) or Dex (1 μM) were added to J774A.1 cultures att=0, 1, 3 or 6 h after LPS. Dex inhibited NO production by 86%, 57%, 35% and 15% at these time points, while CGP 47969A inhibited by 90%, 91%, 89% and 76%. Taken together, the results indicate that CGP 47969A inhibits NO production by an effect similar to the inhibitory effect on cytokine production rather than by inhibition of iNOS enzyme activityper se or iNOS gene expression. The ability of CGP 47969A to inhibit cytokine and NO production may explain its efficacy in animal models of arthritis.