title: Negative feedback regulation of lipopolysaccharide-induced inducible nitric oxide synthase gene expression by heme oxygenase-1 induction in macrophages.
abstract: Heme oxygenase-1 (HO-1) is induced under infectious diseases in macrophages. We performed experiments using various gene deficient mouse-derived macrophages to determine a detailed induction mechanism of HO-1 by lipopolysaccharide (LPS) and the functional role of HO-1 induction in macrophages. LPS (1 microg/mL) maximally induced inducible nitric oxide synthase (iNOS) and HO-1 mRNAs in wild-type (WT) macrophages at 6h and 12h after treatment, respectively, and liberated tumor necrosis factor alpha (TNFalpha) from WT macrophages. LPS also induced iNOS and HO-1 in TNFalpha(-/-) macrophages, but not in iNOS(-/-) macrophages. Interestingly, although LPS strongly induced iNOS, it failed to induce HO-1 almost completely in nuclear-factor erythroid 2-related factor 2 (Nrf2)(-/-) macrophages. The LPS-induced iNOS gene expression was suppressed by pretreatment with HO-1 inducers, hemin and Co-protoporphyrin (CoPP), but not with HO-1 inhibitor, Sn-protoporphyrin in WT macrophages. In the Nrf2(-/-) macrophages, the ability of CoPP to induce HO-1 and its inhibitory effect on the LPS-induced iNOS gene expression were lower than seen in WT macrophages. The present findings suggest that HO-1 is induced via NO-induced nuclear translocation of Nrf2, and the enzymatic function of HO-1 inhibits the overproduction of NO in macrophages.
authors.affiliation: Department of Biochemical Toxicology, School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan. ashino@pharm.showa-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Ashino
authors.forename: Rieko
authors.initials: R
authors.lastname: Yamanaka
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shimokawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Sekikawa
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Iwakura
authors.forename: Seiji
authors.initials: S
authors.lastname: Shioda
authors.forename: Satoshi
authors.initials: S
authors.lastname: Numazawa
authors.forename: Takemi
authors.initials: T
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D025461:Feedback, Physiological / Q000187:drug effects*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D020672:I-kappa B Proteins / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology* / Q000378:metabolism; D008665:Metalloporphyrins / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D052247:Nitric Oxide Synthase Type II / Q000172:deficiency / Q000235:genetics*; D010766:Phosphorylation / Q000187:drug effects; D011524:Protoporphyrins / Q000494:pharmacology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000172:deficiency
chemical_list: D016207:Cytokines; D020672:I-kappa B Proteins; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D008665:Metalloporphyrins; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; C000606205:Nfkbia protein, mouse; D011524:Protoporphyrins; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; C007095:cobaltiprotoporphyrin; C032628:tin protoporphyrin IX; D052247:Nitric Oxide Synthase Type II; D051547:Heme Oxygenase-1