Pentamidine: an inhibitor of interleukin-1 that acts via a post-translational event

Pharmacologic inhibition of cytokines, particularly interleukin-1 (IL-1), potentially has numerous therapeutic applications in inflammatory diseases. We demonstrate that pentamidine, an aromatic diamidine currently used to treat Pneumocystis carinii pneumonia, is a specific and effective inhibitor of cellular IL-1 release from macrophages, and we have shown that this blockage occurs at neither the transcriptional nor the translational level. Pentamidine induced inhibition of IL-1 occurs via an alteration in the post-translational modification of the protein, altering the intracellular and/or membrane cleavage of the 31-kDa pro-IL-1 to the 17-kDa secreted form. In addition, pentamidine exhibited less broad immunosuppressive actions when compared to a corticosteroid, the classical therapeutics utilized for inhibition of cytokine production.