Imidazo[1,2-a]pyridine derivatives as inhibitors of TNF-alpha expression in T cells.

Novel hexahydroimidazo[1,2-a]pyridines prepared by the addition of ethyl (1-benzylimidazolidin-2-ylidene)acetate (2) to the fungal metabolite podoscyphic acid (1a) and esters of 1a have been evaluated for their ability to inhibit the inducible TNF-alpha promoter activity in T cells. The methyl ester 3b is the most potent, inhibiting the TNF-alpha driven reporter gene expression in Jurkat T cells with an IC(50)-value of 2.0 microg/ml (3.6 microM). In addition, compound 3b inhibited the inducible TNF-alpha production in the myelomonocytic U937 cells with an IC(50)-value of 4.6 microM.

Inhibition of inducible tumor necrosis factor-alpha expression by the fungal epipolythiodiketopiperazine gliovirin.

TNF-alpha is a major pro-inflammatory cytokine that regulates further cytokine induction, especially of IL-1 and IL-6, in many human diseases including cancer, inflammation and immune disorders. In a search for new inhibitors of inducible TNF-alpha promoter activity and expression, cultures of the imperfect fungus Trichoderma harzianum were found to produce gliovirin, a previously isolated epipolythiodiketopiperazine. Gliovirin inhibited inducible TNF-alpha promoter activity and synthesis in LPS/IFN-gamma-stimulated macrophages/monocytes and Jurkat T-cells, co-stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA)/ionomycin, in a dose-dependent manner, with IC(50) values ranging from 0.21 to 2.1 microM (0.1-1 microg/ml). Studies on the mode of action revealed that gliovirin suppresses TNF-alpha synthesis by inhibiting the activation of extracellular signal-regulated kinase (ERK), thereby blocking the pathway leading to activation of the transcription factors AP-1 and NF-kappaB, the latter of which is involved in the inducible expression of many pro-inflammatory genes. Gliovirin also significantly reduced TPA/ionomycin-induced IL-2 mRNA levels and synthesis in Jurkat cells at low micromolar concentrations.

Inhibition of TNF-alpha promoter activity and synthesis by A11-99-1, a new cyclopentenone from the ascomycete Mollisia melaleuca.

In a search for inhibitors of the inducible tumor necrosis factor-a (TNF-a) promoter activity and synthesis, a new chlorinated cyclopentenone was isolated from fermentations of the ascomycete Mollisia melaleuca. The structure was determined by a combination of spectroscopic techniques The compound blocked the inducible human TNF-alpha promoter activity and synthesis with IC50-values of 2.5-5 microg/ml (8.1-16.1 microM). Studies on the mode of action of the compound revealed that the inhibition of TNF-a promoter activity is caused by an inhibition of the phosphorylation of the IkappaB protein which prevents the activation of the transcription factor NF-xB. No cytotoxic, antibacterial and antifungal activities could be observed up to 100 microg/ml (323 microM) of the compound.

Oxaspirodion, a new inhibitor of inducible TNF-alpha expression from the Ascomycete chaetomium subspirale. Production, isolation and structure elucidation.

In a search for new inhibitors of the TNF-alpha promoter activity, a new spiro-compound, designated oxaspirodion, was obtained as a mixture of four isomers from fermentations of the ascomycete Chaetomium subspirale. The structure was determined by a combination of spectroscopic techniques.

Inhibition of inducible TNF-alpha expression by oxaspirodion, a novel spiro-compound from the ascomycete Chaetomium subspirale.

In a search for compounds inhibiting the inducible TNF-alpha promoter activity in T cells, a new spiro-compound, designated oxaspirodion, was isolated from fermentations of the ascomycete Chaetomium subspirale. Oxaspirodion inhibited TNF-alpha promoter-driven luciferase reporter gene expression with an IC50 value of 2.5 microg/ml (10 microM) in TPA/ionomycin-stimulated Jurkat T cells. Studies on the mode of action of the compound revealed that the inhibition of the TNF-alpha promoter activity is caused by an inhibition of the phosphorylation of the ERK1/2 kinases. In addition, oxaspirodion inhibited the activation of the transcription factor NF-kappaB, which is involved in the inducible expression of many proinflammatory genes.

S14-95, a novel inhibitor of the JAK/STAT pathway from a Penicillium species.

In a search for new inhibitors of the IFN-gamma mediated signal transduction in HeLa S3 cells using secreted alkaline phosphatase (SEAP) as reporter gene, a novel compound, designated as S14-95 was isolated from fermentations of the imperfect fungus Penicillium sp. 14-95. The compound inhibits the IFN-gamma mediated expression of the reporter gene with IC50 values of 2.5 to approximately 5 microg/ml (5.4 to approximately 10.8 microM). Furthermore the compound inhibited the expression of the proinflammatory enzymes COX-2 and NOS II at 5 microg/ml (10.8 microM) in LPS/IFN-gamma stimulated J774 mouse macrophages. Studies on the mode of action of the compound revealed that the inhibition of the IFN-gamma dependent signaling pathway is caused by an inhibition of the phosphorylation of the STAT1alpha transcription factor. In addition, S14-95 inhibited the activation of the p38 MAP kinase, which is involved in the inducible expression of many proinflammatory genes.