Cytoplasmic bacterial lipopolysaccharide does not induce NFκB activation or NFκB mediated activation signals in human macrophages and an LPS reporter cell line
Cytoplasmic bacterial lipopolysaccharide does not induce NFκB activation or NFκB mediated activation signals in human macrophages and an LPS reporter cell line
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DOI：
10.1002/jcp.10177
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发表时间：
2003-01-01
影响因子：
5.6
通讯作者：
Gerdes, J
中科院分区：
文献类型：
--
作者：
Seitzer, U;Gerdes, J
虽然许多膜成分已被描述为参与细菌脂多糖（LPS）的细胞活化，但问题仍然是LPS一旦被靶细胞内化，是否也能够与细胞质元件相互作用，从而使细胞活化独立于受体接合。这是一个重要的方面，考虑有关的发展战略，旨在减轻不利影响的LPS在细菌感染的框架。在这项研究中，人单核细胞衍生的巨噬细胞作为LPS激活的主要靶细胞之一的代表，用LPS显微注射以规避外源性LPS刺激。研究了与核转录因子NF κ B的细胞质活化（细胞内钙动员）、NF κ B p65亚基的核转位和已知在外源性LPS刺激后表达并需要NF κ B活化的炎性细胞因子（白细胞介素-1 β、白细胞介素-6、肿瘤坏死因子α）的mRNA转录相关的参数。此外，分析了LPS-报告基因细胞系3E 10的NF κ B核易位和报告基因表达，所述LPS-报告基因细胞系3E 10含有在NF κ B诱导型启动子控制下的报告基因。与外部LPS刺激相比，所使用的细胞系统和所研究的参数均未导致观察到细胞内LPS导致细胞活化。这些实验允许这样的结论，即细胞质区室中的LPS不会导致NF κ B易位、细胞因子mRNA转录和NF κ B依赖性蛋白表达，并且表明这些活化参数需要LPS与外部膜组分的相互作用。
Although many membrane components have been described to be involved in the activation of cells by bacterial lipopolysaccharide (LPS), the question remains whether LPS, once internalized by target cells, is also capable of interacting with cytoplasmic elements in such away that activation of cells results independently of receptor engagement. This is an important aspect to consider with respect to the development of strategies aimed at attenuating adverse effects of LPS in the framework of bacterial infections. In this study, human monocyte derived macrophages as representatives of one of the primary target cells activated by LPS, were microinjected with LPS to circumvent exogenous LPS stimulation. Parameters correlating to cytoplasmic activation of the nuclear transcription factor NFkappaB (intracellular calcium mobilization), to nuclear translocation of the NFkappaB p65 subunit and to mRNA-transcription of inflammatory cytokines known to be expressed upon exogenous LPS-stimulation and to require NFkappaB activation (interleukin-1 beta, interleukin-6, tumor necrosis factor alpha) were investigated. In addition, the LPS-reporter cell line 3E10, which contains a reporter gene under the control of an NFkappaB-inducible promoter was analyzed with respect to NFkappaB nuclear translocation and reporter gene expression. None of the cellular systems used and none of the parameters investigated led to the observation that intracellular LPS leads to activation of the cells in comparison to external LPS stimulation. These experiments allow the conclusion that LPS in the cytoplasmic compartment does not lead to NFkappaB translocation, cytokine mRNA transcription, and NFkappaB dependent protein expression and suggest that these activation parameters require the interaction of LPS with external membrane components.