Differential expression of claudin-2 along the human intestine: Implication of GATA-4 in the maintenance of claudin-2 in differentiating cells
Differential expression of claudin-2 along the human intestine: Implication of GATA-4 in the maintenance of claudin-2 in differentiating cells
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DOI：
10.1002/jcp.20189
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发表时间：
2005-04-01
影响因子：
5.6
通讯作者：
Beaulieu, JF
中科院分区：
文献类型：
--
作者：
Escaffit, F;Boudreau, F;Beaulieu, JF
克劳丁蛋白，尤其是克劳丁 - 2，是紧密连接通透性的重要调节成分。要更好地理解克劳丁 - 2在肠道屏障功能中的作用，就需要对其在肠道中的分布和调节进行表征。有趣的是，克劳丁 - 2基因启动子与蔗糖酶 - 异麦芽糖酶（一种肠细胞分化的标志物）的启动子有许多相似之处。因此，我们研究了克劳丁 - 2在人肠道中与转录因子CDX2、HNF - 1α和GATA - 4相关的表达情况。通过免疫荧光、蛋白质印迹和逆转录聚合酶链反应在发育中的人肠上皮细胞中对克劳丁 - 2进行表征以及对上述转录因子的表达进行研究。还通过在肠道细胞模型中的异位表达研究检测了CDX2、HNF - 1α和GATA - 4对克劳丁 - 2调节的功能作用。在小肠的隐窝细胞和绒毛细胞中都检测到了克劳丁 - 2，但在结肠中仅限于未分化的隐窝细胞。CDX2和HNF - 1α在整个肠道中都有表达，而GATA - 4在结肠中未检测到。相应地，在结肠Caco - 2细胞模型中，发现克劳丁 - 2仅存在于未分化细胞中。与结肠上皮细胞一样，发现Caco - 2细胞中也缺乏GATA - 4，而CDX2和HNF - 1α则有显著水平的表达。共转染实验表明，克劳丁 - 2启动子被CDX2、HNF - 1α和GATA - 4以协同方式激活。此外，在Caco - 2细胞中强制表达GATA - 4可增强分化过程中克劳丁 - 2表达的维持。这些观察结果表明，肠道中克劳丁 - 2的最佳表达依赖于GATA - 4的存在，这表明该因子在肠道区域化中起作用。（C）2004威利 - 利斯公司
Claudins, and particularly claudin-2, are important regulatory components of tight junction permeability. Abetter understanding of the involvement of claudin-2 in intestinal barrier functions requires the characterization of its distribution and regulation in the intestine. Interestingly, the claudin-2 gene promoter harbors a number of similarities to that of sucrase-isomaltase, a marker of enterocyte differentiation. We thus investigated the expression of claudin-2 in relation to the transcription factors CDX2, HNF-1alpha, and GATA-4 in the human intestine. The characterization of claudin-2 and the expression of the above transcription factors were performed by immunofluorescence, Western blot, and RT-PCR in the developing human intestinal epithelium. The functional role of CIDX2, HNF-1alpha, and GATA-4 on claudin-2 regulation was also examined by ectopic expression studies in intestinal cell models. Claudin-2 was detected in both crypt and villus cells of the small intestine but restricted to undifferentiated crypt cells in the colon. CDX2 and HNF-1alpha were expressed along the entire intestine whereas GATA-4 was undetectable in the colon. Accordingly, in the colonic Caco-2 cell model, claudin-2 was found to be present only in undifferentiated cells. Like in the colonic epithelium, GATA-4 was found to be also lacking in Caco-2 cells while CDX2 and HNF-1alpha were presentat significant levels. Cotransfection experiments showed that the claudin-2 promoter was activated by CDX2, HNF-1alpha, and GATA-4 in a cooperative manner. Furthermore, forced GATA-4 expression in Caco-2 cells enhances maintenance of claudin-2 expression during differentiation. These observations suggest that optimal claudin-2 expression in the gut relies on the presence of GATA-4, suggesting a role for this factor in intestinal regionalization. (C) 2004 Wiley-Liss, Inc.