Disruption of tight junctions during polymicrobial sepsis in vivo
Disruption of tight junctions during polymicrobial sepsis in vivo
复制标题
体内多种微生物败血症期间紧密连接的破坏
DOI：
10.1002/path.2525
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发表时间：
2009-06-01
影响因子：
7.3
通讯作者：
Li, Jieshou
中科院分区：
文献类型：
--
作者：
Li, Qiurong;Zhang, Qiang;Li, Jieshou
在多菌败血症时，肠上皮紧密连接的破坏可能导致屏障功能障碍。脓毒症的病理生理学涉及屏障完整性的破坏，这与脓毒症期间的不良后果相关。然而，脓毒症中屏障功能丧失的潜在机制仍不清楚。在本研究中，用透射电子显微镜分析小鼠紧密连接(TJ)的结构，用分子示踪法测定肠道通透性，用免疫荧光显微镜观察TJ蛋白的分布。用不连续蔗糖密度梯度法分离TJ膜微区，并用免疫印迹法检测TJ蛋白在其中的表达。免疫荧光显微镜显示，Claudins 1、3、4、5和8主要存在于上皮细胞的微绒毛表面和细胞的侧膜上；然而，在脓毒症中，这些蛋白的标记广泛存在于细胞内，不再集中在细胞的侧缘。此外，脓毒症时claudin-2的表达明显上调。免疫印迹分析发现，在脓毒症患者TJ膜微区中，occludin和claudins从RAFT组分向非RAFT组分转移。此外，TJ结构的破坏伴随着肠道通透性的增加。我们的结果首次证实，在多菌败血症的发生发展过程中，TJ蛋白在TJ膜微区的重新分布和Claudins在结肠上皮细胞中的重新分布导致了TJ构筑的改变和TJ屏障的功能障碍。版权所有(C)2009年英国和爱尔兰病理学会。作者：John Wiley&Sons，Ltd.
The disruption of intestinal epithelial tight junctions may result in barrier function dysfunction during polymicrobial sepsis. The pathophysiology of sepsis involves breakdown of barrier integrity, which correlates with adverse outcome during sepsis. However, the mechanisms underlying loss of barrier function in sepsis remain unknown. In the present study in mice, tight junction (TJ) structure was analysed by transmission electron microscopy; intestinal permeability was assessed using molecular tracer measurement; and the distribution of TJ proteins was investigated by immunofluorescence microscopy. The membrane microdomains of TJs were isolated using discontinuous sucrose density gradients and the expression of TJ proteins in these was determined by western blot. Immunofluorescence microscopy revealed that claudins 1, 3, 4, 5, and 8 were present predominantly in the microvillous surface of epithelial cells and along the lateral membranes of the cells; in sepsis, however, labelling of these proteins was present diffusely within cells and was no longer focused at the lateral cell boundaries. Moreover, the expression of claudin‐2 was markedly up‐regulated in sepsis. Using western blot analysis, we found that occludin and claudins were displaced from raft fractions to non‐raft fractions in membrane microdomains of TJs in sepsis. In addition, the disruption of TJ structure was accompanied by increased intestinal permeability. Our results demonstrate for the first time that redistribution of TJ proteins in TJ membrane microdomains and redistribution of claudins in epithelial cells of the colon lead to alteration of TJ architecture and TJ barrier dysfunction during the development of polymicrobial sepsis. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.