Effects of verocytotoxin-1 on nonadherent human monocytes: binding characteristics, protein synthesis, and induction of cytokine release.
Effects of verocytotoxin-1 on nonadherent human monocytes: binding characteristics, protein synthesis, and induction of cytokine release.
复制标题
Verocytotoxin-1 对非贴壁人单核细胞的影响：结合特性、蛋白质合成和细胞因子释放的诱导。
作者：
P. V. Setten;L.A.H. Monnens;R.G.G. Verstraten;L.P.W.J. van den Heuvel;Vwh Van Hinsbergh
溶血性尿毒综合征（HUS）的流行形式与产生verocytotoxin的大肠杆菌感染有关。肾小球和肾小动脉内皮细胞损伤在HUS的发病机制中起着重要作用。许多体内和体外观察表明，炎症介质有助于这一过程。在这项研究中，我们调查了125碘-verocytotoxin-1（VT-1）的结合，以新鲜分离的人非粘附单核细胞，以及VT-1结合单核细胞的配体的性质。平均而言，新鲜分离的单核细胞每个细胞具有0.07 × 105个125 I-VT-1特异性结合位点。如Scatchard图分析所示，用细菌脂多糖（LPS）预孵育非粘附单核细胞导致VT-1特异性结合位点增加23至30倍。提取的细胞中性糖脂的薄层色谱法和随后的125 I-VT-1结合显示，人单核细胞将VT-1结合到与内皮细胞上发现的不同的神经酰胺三己糖苷（Gb 3）种类，可能是短链脂肪酰基Gb 3或α-OH-Gb 3。此外，我们通过研究VT-1对总蛋白质合成的影响，特别是对细胞因子白细胞介素-1 β（IL-1 β）、肿瘤坏死因子-α（TNF-α）、IL-6和IL-8的产生的影响，评估了VT-1与人单核细胞结合的功能后果。我们观察到，VT-1不抑制整体蛋白质合成，也没有在基础条件下，无论是在用LPS刺激后，与以前的观察与内皮细胞。此外，我们发现，VT-1诱导的细胞因子IL-1 β，TNF-α，IL-6，和IL-8的合成在非刺激的单核细胞通过LPS-非依赖性细胞活化。细胞因子产生的增加与mRNA的增加平行，如通过逆转录-聚合酶链反应对IL-6所证明的。这些数据表明，由VT-1刺激的单核细胞局部产生的炎症介质可能有助于HUS的致病机制。
The epidemic form of the hemolytic uremic syndrome (HUS) has been associated with a verocytotoxin producing Escherichia coli infection. Endothelial cell damage of glomeruli and arterioles of the kidney plays a central role in the pathogenesis of HUS. A number of observations in vivo and in vitro indicate that inflammatory mediators contribute to this process. In this study we investigated the binding of 125I-verocytotoxin-1 (VT-1) to freshly isolated human nonadherent monocytes as well as the nature of the ligand to which VT-1 binds on monocytes. On the average, freshly isolated monocytes have 0.07 x 10(5) specific binding sites for 125I-VT-1 per cell. Preincubation of nonadherent monocytes with bacterial lipopolysaccharide (LPS) caused a 23- to 30-fold increase of specific binding sites for VT-1 as shown by Scatchard plot analysis. Thin-layer chromatography of extracted neutral glycolipids of the cells and subsequent binding of 125I-VT-1 showed that human monocytes bind VT-1 to a globotriaosylceramide (Gb3) species that is different from that found on endothelial cells, probably a short-chain fatty acyl Gb3 or an alpha-OH-Gb3. In addition, we evaluated the functional consequences of VT-1 binding to human monocytes by investigating the effects of VT-1 on the total protein synthesis and, specifically, the production of the cytokines interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), IL-6, and IL-8. We observed that VT-1 did not inhibit overall protein synthesis, nor under basal conditions, neither after stimulation with LPS, in contrast to previous observations with endothelial cells. Furthermore, we found that VT-1 induces the synthesis of the cytokines IL-1 beta, TNF-alpha, IL-6, and IL-8 in nonstimulated monocytes by a LPS-independent cell activation. The increase in the production of cytokines was parallelled by an increase in mRNA, as was demonstrated for IL-6 by reverse transcription-polymerase chain reaction. These data suggest that inflammatory mediators locally produced by VT-1-stimulated monocytes may contribute to the pathogenic mechanism of the HUS.
影响因子：
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作者：
LAMAS, S;MICHEL, T;MARSDEN, PA
通讯作者：
MARSDEN, PA