Elevated production of
tumor necrosis factor (TNF) plays a central role in the pathogenesis of many inflammatory diseases, such as
rheumatoid arthritis and
Crohn's disease. Naturally occurring
pteridine analogs have been reported to have potent immunomodulatory activity, especially on TNF production. The aim of this study is to identify small molecule TNF inhibitiors derived from
pteridine and to prove their in vivo efficacy in an inflammatory model. A focused chemical library based on the
pteridine scaffold was screened in vitro on
lipopolysaccharide (LPS)-induced TNF production in peripheral blood mononuclear cells (PBMC). One synthetic
pteridine analog (
4AZA2096), shown to have strong inhibitory activity, was selected and tested for its efficacy to treat trinitrobenzenesulfonate (TNBS)-induced
colitis in mice, a model of
Crohn's disease.
Colitis was induced by
rectal administration of 1 mg TNBS in 50%
ethanol after presensitization via the skin. The synthetic
pteridine analog
4AZA2096 was shown to potently inhibit LPS-induced TNF production in vitro. Colitic mice treated with
4AZA2096 orally (20 mg/kg/day) recovered more rapidly and, histologically, had a reduction of inflammatory lesions, less
edema, a reduction of goblet cell loss, and reduced wall thickness. Cell infiltration in the colon, especially infiltration of neutrophils, as shown by
myeloperoxidase (MPO) activity, was reduced in 4AZA2096-treated animals. Intralesional TNF production was lower in mice of the treated groups, whereas
interleukin-18 (IL-18) and
interferon-gamma (IFN-gamma)
mRNA were not affected. Treatment had no effect on anti-TNBS antibody production, arguing against generalized immunosuppression. In conclusion, we identified a
pteridine derivative,
4AZA2096, with strong inhibitory activity on TNF production and a remission- inducing effect in TNBS
colitis, supporting further preclinical and clinical development of this novel
TNF inhibitor for treatment of inflammatory diseases.