title: Kupffer cell depletion partially prevents hepatic heme oxygenase 1 messenger RNA accumulation in systemic inflammation in mice: role of interleukin 1beta.
abstract: The heme oxygenase 1 (HO-1) gene is rapidly activated in the liver after lipopolysaccharide (LPS) treatment. Ninety minutes after LPS treatment (0.1 mg/kg, intraperitoneally) hepatic HO-1 messenger RNA (mRNA) of mice was 40 times the control value. To investigate the hepatic cellular source of the increased HO-1 transcript, we treated mice with LPS and galactosamine (700 mg/kg, intraperitoneally), a selective transcriptional inhibitor of hepatocytes. Galactosamine prevented the LPS-mediated increase of HO-1 mRNA in the liver, indicating that hepatocytes are the main cell type in which HO-1 mRNA accumulates after LPS treatment. We then tested in vitro and in vivo the hypothesis that LPS-mediated hepatic accumulation of HO-1 mRNA is caused by intercellular communication between Kupffer cells and hepatocytes. Isolated rat hepatocytes showed an increase in HO-1 mRNA compared with controls after 90 minutes of exposure to a LPS stimulated Kupffer cell-conditioned medium. This suggests that soluble mediators from Kupffer cells were responsible for this effect. To study the role of Kupffer cells in vivo, we treated mice with Kupffer cell-inactivating or -depleting agents and LPS. Gadolinium chloride and liposome-encapsulated dichloromethylene diphosphonate lowered LPS-mediated HO-1 mRNA accumulation (by about 50%); in these groups hepatic levels of interleukin (IL)-1beta were decreased, by more than 75%. Methylpalmitate hardly affected hepatic HO-1 mRNA accumulation or IL-1beta content after LPS treatment. There was no relationship between HO-1 mRNA and serum TNF or IL-6 levels. These results suggest that LPS-mediated hepatic HO-1 mRNA accumulation is a hepatocyte response partly caused by soluble mediators, particularly IL-1beta, released from Kupffer cells.
authors.affiliation: Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Rizzardini
authors.forename: M
authors.initials: M
authors.lastname: Zappone
authors.forename: P
authors.initials: P
authors.lastname: Villa
authors.forename: P
authors.initials: P
authors.lastname: Gnocchi
authors.forename: M
authors.initials: M
authors.lastname: Sironi
authors.forename: L
authors.initials: L
authors.lastname: Diomede
authors.forename: C
authors.initials: C
authors.lastname: Meazza
authors.forename: M
authors.initials: M
authors.lastname: Monshouwer
authors.forename: L
authors.initials: L
authors.lastname: Cantoni
mesh_terms: D000818:Animals; D016207:Cytokines / Q000096:biosynthesis; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics*; D007249:Inflammation / Q000378:metabolism*; D007375:Interleukin-1 / Q000502:physiology*; D007728:Kupffer Cells / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D016207:Cytokines; D007375:Interleukin-1; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D006419:Heme Oxygenase (Decyclizing)