title: Excretory/secretory products of plerocercoids of Spirometra erinaceieuropaei induce the expression of inducible nitric oxide synthase mRNA in murine hepatocytes.
abstract: In this study, we observed the level of normal murine hepatocyte inducible NOS (iNOS) mRNA by semi-quantitative polymerase chain reaction (SQ-PCR) analysis after stimulation with ES products (ESP) and/or ESP fractions from the plerocercoids. We found that ESP are able to induce the expression of iNOS gene in a dose-dependent fashion. Treatment of ESP with polymyxin B did not affect their ability to induce the expression of iNOS gene, suggesting that bacterial lipopolysaccharide (LPS) is not involved. The iNOS-inducing factor (a) is soluble, and may be a component whose molecular mass exceeds 94 kDa as analyzed by a combination of SDS-PAGE and SQ-PCR. The peak of iNOS mRNA level was detected 3 h after stimulation with ESP; the mRNA level decreased sharply from 9 h. Dexamethasone inhibited the induction of mRNA for hepatocyte iNOS. In contrast, cycloheximide stimulated the induction; this suggests that de nova protein synthesis is important in the regulation of the ESP-induced expression of iNOS mRNA. Actinomycin D blocked the induction. In addition, the results of Northern blot analysis showed that ESP suppressed the LPS (10 micrograms/ml) and interferon-gamma (IFN-gamma, 100 U/ml)-induced hepatocyte iNOS mRNA expression in a dose-dependent fashion and the suppressing effect was more marked when hepatocytes were exposed to ESP 3 h prior to LPS and IFN-gamma. These results demonstrate that the soluble factor(s) of ESP is capable of inducing murine iNOS gene expression in hepatocytes in the absence of added cytokines.
authors.affiliation: Department of Medical Zoology, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: T
authors.initials: T
authors.lastname: Tanihata
authors.forename: S
authors.initials: S
authors.lastname: Fukumoto
authors.forename: K
authors.initials: K
authors.lastname: Hirai
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004790:Enzyme Induction; D005786:Gene Expression Regulation / Q000187:drug effects; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000166:cytology / Q000201:enzymology* / Q000469:parasitology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D019001:Nitric Oxide Synthase / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger; D013146:Spirometra / Q000254:growth & development / Q000502:physiology*
chemical_list: D008070:Lipopolysaccharides; D012333:RNA, Messenger; D003609:Dactinomycin; D003907:Dexamethasone; D007371:Interferon-gamma; D003513:Cycloheximide; D019001:Nitric Oxide Synthase