Knolle P A, Uhrig A, Protzer U, Trippler M, Duchmann R, Meyer zum Büschenfelde K H, Gerken G
Zentrum für Molekulare Biologie Heidelberg, Ruprecht-Karls-Universität , Germany.
Hepatology. 1998 Jan;27(1):93-9. doi: 10.1002/hep.510270116.
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.
白细胞介素10（IL-10）已知可下调免疫反应。因此，IL-10基因表达的调控决定了局部免疫反应的结果。我们研究了原代库普弗细胞（KC）中IL-10产生的时间进程和下调情况，已知这些细胞在受到内毒素刺激时会分泌IL-10。通过离心淘析分离出人及小鼠的KC，并通过两步扩增程序（逆转录-聚合酶链反应[PCR]，随后是T7-聚合酶链反应）研究IL-10基因表达。我们发现，在内毒素刺激后2小时，KC中的IL-10信使核糖核酸（mRNA）增加了450倍以上。KC释放IL-10蛋白严格依赖于从头合成蛋白质。外源性（IL-10 mRNA水平降低>350倍）以及内源性IL-10蛋白均下调了内毒素介导的IL-10基因表达增加，显示出负性自调节反馈环。发现IL-10受体在KC中组成性表达且具有功能。KC中IL-10的早期表达可能与肝血窦中免疫和炎症反应的结果具有功能相关性。IL-10表达的负性自调节可能代表一种机制，使微环境恢复对新的促炎刺激的功能反应状态。总之，KC中IL-10表达的自调节下调可能是肝血窦局部免疫反应重要调节步骤的原因。
