Changes in the expression of claudins in active ulcerative colitis
Changes in the expression of claudins in active ulcerative colitis
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DOI：
10.1111/j.1440-1746.2008.05405.x
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发表时间：
2008-12-01
影响因子：
4.1
通讯作者：
Joh, Takashi
中科院分区：
文献类型：
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作者：
Oshima, Tadayuki;Miwa, Hiroto;Joh, Takashi
溃疡性结肠炎（UC）的上皮屏障功能受损，但导致这种屏障缺陷的病理生理机制仍远不清楚。由于上皮屏障功能主要是由最顶端的细胞间连接，被称为紧密连接（TJ），我们研究了TJ蛋白的表达直肠上皮粘膜在UC。活组织检查从活跃的UC患者和对照组的直肠进行了研究。使用特异性抗体（claudin-1、claudin-2、claudin-3、claudin-4和claudin-7）作为第一抗体，使用Cy-3缀合的抗兔IgG和Alexa 488缀合的抗小鼠IgG作为第二抗体，对紧密连接蛋白进行双重染色。通过免疫荧光显微镜分析样品。免疫印迹和实时聚合酶链反应分别定量TJ蛋白和mRNA。在TJ，claudin-4和-7染色在活动性UC中下调，而claudin-2染色上调。Claudin-4和-7蛋白在免疫印迹中下调，而claudin-2蛋白在活动性UC中上调。Claudin-1和-3表达水平在对照组和活动性UC中无变化。活动期UC中claudin-2 mRNA表达增加，claudin-4和claudin-7 mRNA表达减少，claudin-4和claudin-7表达下调，claudin-2表达上调，可能导致TJ结构改变，与活动期UC上皮功能受损有关。
Epithelial barrier function is impaired in ulcerative colitis (UC), but the pathophysiological mechanisms leading to this barrier defect are still far from clear. Because epithelial barrier function is primarily regulated by the most apical intercellular junction, referred to as the tight junction (TJ), we investigated the expression of TJ proteins on rectal epithelial mucosa in UC.Biopsies from the rectum of patients with active UC and of controls were studied. Tight-junction proteins were dual stained using specific antibodies (claudin-1, -2, -3, -4, and -7) as primary antibodies, and Cy-3 conjugated anti-rabbit IgG and Alexa488-conjugated anti-mouse IgG as secondary antibodies. Samples were analyzed by immunofluorescence microscopy. Immunoblotting and real-time polymerase chain reaction were performed to quantify TJ proteins and mRNA, respectively.At TJ, claudin-4 and -7 staining was down-regulated in active UC, whereas claudin-2 staining was up-regulated. Claudin-4 and -7 proteins were down-regulated on immunoblotting, whereas claudin-2 protein was up-regulated in active UC. Claudin-1 and -3 expression levels were unchanged in controls and active UC. In active UC claudin-2 mRNA was increased, whereas claudin-4 and -7 mRNA were decreased.Down-regulation of claudin-4 and claudin-7, and up-regulation of claudin-2, might lead to altered TJ structure and be related to the impaired epithelial function in active UC.