title: Sporogen, S14-95, and S-curvularin, three inhibitors of human inducible nitric-oxide synthase expression isolated from fungi.
abstract: The induction of human inducible nitric-oxide synthase (iNOS) expression depends (among other factors) on activation of the signal transducer and activator of transcription 1 (STAT1) pathway. Therefore, the STAT1 pathway may be an appropriate target for the development of inhibitors of iNOS expression. HeLa S3 cells transiently transfected with a gamma-activated site (GAS)/interferon-stimulated response element-driven reporter gene construct were used as the primary screening system. Using this system, three novel inhibitors of interferon-gamma-dependent gene expression, namely, sporogen, S14-95, and S-curvularin, were isolated from different Penicillium species. These three compounds also inhibited cytokine-induced, GAS-dependent reporter gene expression in stably transfected human A549/8-pGASLuc cells, confirming the data obtained with the above-mentioned screening system. Furthermore, in A549/8 cells, sporogen, S14-95, and S-curvularin inhibited cytokine-induced activity of the human iNOS promoter [a 16-kilobase (kb) fragment in stably transfected A549/8-pNOS2(16)Luc cells], cytokine-induced iNOS mRNA expression, and cytokine-induced nitric oxide (NO) production in a concentration-dependent manner. The proliferation of A549/8 cells, and the activity of the human eNOS promoter (a 3.5-kb fragment in stably transfected ECV-pNOS III-Hu-3500-Luc cells), were only influenced marginally by the three compounds. Sporogen, S14-95, and S-curvularin also inhibited cytokine-induced activation of STAT1alpha in A549/8 cells. In conclusion, sporogen, S14-95, and S-curvularin represent new transcriptionally based inhibitors of iNOS-dependent NO production, acting on the Janus tyrosine kinase-STAT pathway. These compounds may represent lead structures for the development of drugs inhibiting iNOS-dependent overproduction of NO in pathophysiological situations.
authors.affiliation: Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yao
authors.forename: Michael
authors.initials: M
authors.lastname: Hausding
authors.forename: Gerhard
authors.initials: G
authors.lastname: Erkel
authors.forename: Timm
authors.initials: T
authors.lastname: Anke
authors.forename: Ulrich
authors.initials: U
authors.lastname: Förstermann
authors.forename: Hartmut
authors.initials: H
authors.lastname: Kleinert
mesh_terms: D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004852:Epoxy Compounds / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors* / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009573:Nitrites / Q000378:metabolism; D010407:Penicillium / Q000737:chemistry*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D050794:STAT1 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism; D015025:Zearalenone / Q000031:analogs & derivatives* / Q000494:pharmacology*
chemical_list: D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D004852:Epoxy Compounds; D009573:Nitrites; D012333:RNA, Messenger; C471131:S14-95; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D015534:Trans-Activators; C471129:sporogen; D015025:Zearalenone; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C013455:curvularin