title: Interleukin-10 expression is autoregulated at the transcriptional level in human and murine Kupffer cells.
abstract: Interleukin 10 (IL-10) is known to downregulate immune responses. The regulation of IL-10 gene expression therefore determines the outcome of local immune reactions. We investigated time course and downregulation of IL-10 production in primary Kupffer's cells (KC), which are known to secrete IL-10 in response to endotoxin challenge. Human and murine KC were isolated by centrifugal elutriation and investigated for IL-10 gene expression by a two-step amplification procedure (reverse transcriptase-polymerase chain reaction [PCR] followed by T7-polymerase chain reaction). We show that IL-10 messenger ribonucleic acid (mRNA) showed a >450 fold increase in KC 2 hours after endotoxin challenge. IL-10 protein release from KC strictly depended on de novo protein synthesis. Endotoxin mediated increase in IL-10 gene expression was downregulated by exogenous (>350-fold reduction of IL-10 mRNA level), as well as endogenous IL-10 protein, showing a negative autoregulatory feedback loop. IL-10 receptor expression was found to be constitutive and functional in KC. Early expression of IL-10 in KC may be of functional relevance to the outcome of immune and inflammatory reactions in the liver sinusoid. The negative autoregulation of IL-10 expression may represent a mechanism to regain a state of functional responsiveness in the microenvironment towards new proinflammatory stimuli. In conclusion, autoregulatory downregulation of IL-10 expression in KC may account for important regulatory steps of local immune response in the liver sinusoid.
authors.affiliation: Zentrum für Molekulare Biologie Heidelberg, Ruprecht-Karls-Universität , Germany.
authors.forename: P A
authors.initials: PA
authors.lastname: Knolle
authors.forename: A
authors.initials: A
authors.lastname: Uhrig
authors.forename: U
authors.initials: U
authors.lastname: Protzer
authors.forename: M
authors.initials: M
authors.lastname: Trippler
authors.forename: R
authors.initials: R
authors.lastname: Duchmann
authors.forename: K H
authors.initials: KH
authors.lastname: Meyer zum Büschenfelde
authors.forename: G
authors.initials: G
authors.lastname: Gerken
mesh_terms: D000818:Animals; D004731:Endotoxins / Q000494:pharmacology; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics* / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D007728:Kupffer Cells / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000378:metabolism; D018123:Receptors, Interleukin / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D004731:Endotoxins; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D016753:Interleukin-10