title: Methylation-dependent gene silencing induced by interleukin 1beta via nitric oxide production.
abstract: Interleukin (IL)-1beta is a pleiotropic cytokine implicated in a variety of activities, including damage of insulin-producing cells, brain injury, or neuromodulatory responses. Many of these effects are mediated by nitric oxide (NO) produced by the induction of NO synthase (iNOS) expression. We report here that IL-1beta provokes a marked repression of genes, such as fragile X mental retardation 1 (FMR1) and hypoxanthine phosphoribosyltransferase (HPRT), having a CpG island in their promoter region. This effect can be fully prevented by iNOS inhibitors and is dependent on DNA methylation. NO donors also cause FMR1 and HPRT gene silencing. NO-induced methylation of FMR1 CpG island can be reverted by demethylating agents which, in turn, produce the recovery of gene expression. The effects of IL-1beta and NO appear to be exerted through activation of DNA methyltransferase (DNA MeTase). Although exposure of the cells to NO does not increase DNA MeTase gene expression, the activity of the enzyme selectively increases when NO is applied directly on a nuclear protein extract. These findings reveal a previously unknown effect of IL-1beta and NO on gene expression, and demonstrate a novel pathway for gene silencing based on activation of DNA MeTase by NO and acute modification of CpG island methylation.
authors.affiliation: Departamento de Bioquímica Médica y Biología Molecular, Facultad de Medicina y Hospital Universitario Virgen Macarena, Universidad de Sevilla, 41009 Sevilla, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Hmadcha
authors.forename: F J
authors.initials: FJ
authors.lastname: Bedoya
authors.forename: F
authors.initials: F
authors.lastname: Sobrino
authors.forename: E
authors.initials: E
authors.lastname: Pintado
mesh_terms: D000818:Animals; D002455:Cell Division; D019175:DNA Methylation; D015254:DNA Modification Methylases / Q000378:metabolism; D017931:DNA Primers; D015226:Dinucleoside Phosphates; D004789:Enzyme Activation; D051860:Fragile X Messenger Ribonucleoprotein 1; D005600:Fragile X Syndrome / Q000235:genetics; D020868:Gene Silencing / Q000187:drug effects; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D007375:Interleukin-1 / Q000494:pharmacology*; D019169:Jurkat Cells; D008264:Macrophages; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052247:Nitric Oxide Synthase Type II; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D016601:RNA-Binding Proteins / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D026423:S-Nitroso-N-Acetylpenicillamine; D014407:Tumor Cells, Cultured; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D015254:DNA Modification Methylases; D017931:DNA Primers; D015226:Dinucleoside Phosphates; D051860:Fragile X Messenger Ribonucleoprotein 1; D007041:Hypoxanthine Phosphoribosyltransferase; D007375:Interleukin-1; D009419:Nerve Tissue Proteins; D009569:Nitric Oxide; D020030:Nitric Oxide Donors; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D010396:Penicillamine; D016601:RNA-Binding Proteins; D026423:S-Nitroso-N-Acetylpenicillamine; D019323:omega-N-Methylarginine; C497683:FMR1 protein, human; C497684:Fmr1 protein, mouse; C497685:Fmr1 protein, rat; C015772:CpG dinucleotide; C496319:NOS2 protein, human; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat