Inhibition of lipopolysaccharide activation of Kupffer cells by transition metals.
Inhibition of lipopolysaccharide activation of Kupffer cells by transition metals.
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DOI：
10.1016/j.jss.2007.11.726
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发表时间：
2008-08
期刊：
影响因子：
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通讯作者：
P. Thomas;H. Hayashi;D. Lazure;P. Burke;O. Bajenova;A. Ganguly;R. Forse
中科院分区：
文献类型：
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作者：
P. Thomas;H. Hayashi;D. Lazure;P. Burke;O. Bajenova;A. Ganguly;R. Forse
背景：细菌内毒素是引起败血症和败血性休克的主要病原体。细胞与内毒素相互作用产生的细胞因子级联可导致心血管衰竭，进而导致多器官衰竭和死亡。给小鼠静脉注射内毒素可能会产生致命的后果。先前的研究表明过渡金属Mn2+和Cr3+可以起到保护作用。方法：采用斑点印迹、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和Western 转移分析Mn2+、Cr3+、Zn2+ 和Cu2+ 对脂多糖（LPS）与大鼠库普弗细胞提取物结合的影响。通过胶原酶灌注、差速离心和塑料粘附从大鼠肝脏中分离库普弗细胞。结果：5 毫摩尔的 Mn2+、Zn2+、Cr3+ 和 Cu2+ 完全抑制 LPS 结合。分离的 Kupffer 细胞也暴露于 Mn2+ 和 LPS，并测量肿瘤坏死因子-α 的释放。 Mn2+ 的存在显着（P < 0.05）减少库普弗细胞响应 LPS 产生的肿瘤坏死因子-α。确定这些效应是否是通过与 LPS 结合蛋白结合介导的实验表明，情况并非如此。更有可能的是金属和脂多糖之间发生复合物。我们还发现，在 Mn2+ 存在的情况下，库普弗细胞对 LPS 的吸收显着增强。结论：数据与金属通过其两个磷酸基团与 LPS 结合并中和其电荷的情况一致。这些数据还支持这样的假设：非受体介导的方法（例如吸收性胞饮作用）可以增强细胞的摄取。同时受体结合和细胞激活被抑制。这可以解释过渡金属对脂多糖毒性的影响。
BACKGROUND: Bacterial endotoxins are the principal agents causing sepsis and septic shock. Cytokine cascades produced by cellular interactions to endotoxins can cause cardiovascular failure followed by multi-organ failure and death. Endotoxin intravenously administered to mice can have fatal consequences. Previous studies have shown that the transition metals Mn2+and Cr3+can be protective. METHODS: The effects of Mn2+, Cr3+, Zn2+, and Cu2+on lipopolysaccharide (LPS) binding to rat Kupffer cell extracts were analyzed using dot-blots, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western transfer. Kupffer cells were isolated from rat livers by collagenase perfusion, differential centrifugation, and adhesion to plastic. RESULTS: Five millimolar of Mn2+, Zn2+, Cr3+, and Cu2+completely inhibited LPS binding. Isolated Kupffer cells were also exposed to Mn2+and to LPS and tumor necrosis factor-alpha release measured. The presence of Mn2+significantly (P < 0.05) reduced tumor necrosis factor-alpha production by Kupffer cells in response to LPS. Experiments to determine if these effects were mediated by binding to LPS-binding proteins showed this was not the case. More likely a complex occurs between the metal and LPS. We also showed significantly enhanced uptake of LPS into Kupffer cells in the presence of Mn2+.CONCLUSIONS: The data are consistent with the metals binding to LPS via its two phosphate groups and neutralizing their charge. These data also support the hypothesis that there is enhanced cellular uptake by non-receptor-mediated methods such as absorptive pinocytocis. At the same time receptor binding and activation of the cells is inhibited. This can explain the effects of transition metals on LPS toxicity.