Role of C-terminal regions of the C-terminal fragment of Clostridium perfringens enterotoxin in its interaction with claudin-4.
Role of C-terminal regions of the C-terminal fragment of Clostridium perfringens enterotoxin in its interaction with claudin-4.
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DOI：
10.1016/j.jconrel.2005.07.008
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发表时间：
2005-11
期刊：
影响因子：
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通讯作者：
A. Takahashi;M. Kondoh;A. Masuyama;M. Fujii;H. Mizuguchi;Y. Horiguchi;Yoshiteru Watanabe
中科院分区：
文献类型：
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作者：
A. Takahashi;M. Kondoh;A. Masuyama;M. Fujii;H. Mizuguchi;Y. Horiguchi;Yoshiteru Watanabe
Claudin家族蛋白包含4个跨膜结构域，在上皮膜紧密连接（TJs）的屏障功能中起关键作用。我们先前发现，产气荚膜梭菌肠毒素（C-CPE）的c端片段cludin -4的调节剂是大鼠空肠药物吸收的有效促进剂。但C-CPE对TJs屏障功能的影响尚未完全了解。在本研究中，我们研究了C-CPE对cco -2单层TJs屏障功能的影响，并表征了C-CPE负责与cladin -4相互作用的功能域。为了评估C-CPE对TJs屏障功能的影响，我们测量了caco2单层细胞在聚碳酸酯过滤器上的透射上皮电阻（TER）。用C-CPE治疗Caco-2细胞导致TER降低。但是，C-CPE的30个c端氨基酸（被认为是claudin的结合域）的缺失，减弱了TER值的下降。此外，C-CPE的16个c端氨基酸的消融也导致TER值下降的衰减。c端缺失的C-CPE不与cludin -4或cludin -4的胞外结构域2相互作用，后者是C-CPE的结合位点。这些结果表明，在TJ屏障功能被破坏后，C-CPE的16个c端氨基酸负责C-CPE与cladin -4的相互作用。
Claudin family proteins, which contain 4 transmembrane domains, play a pivotal role in the barrier function of tight junctions (TJs) in epithelial sheets. We previously found that a modulator of claudin-4, the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), is a potent enhancer of jejunal drug absorption in rats. But the effects of C-CPE on the barrier function of TJs have never been fully understood. In the present study, we investigated the effects of C-CPE on the barrier function of TJs in Caco-2 monolayer and characterized the functional domain of C-CPE that is responsible for interaction with claudin-4. To evaluate the effects of C-CPE on the barrier function of TJs, we measured transepithelial electric resistance (TER) in Caco-2 monolayer cells seeded onto polycarbonate filters. Treatment of Caco-2 cells with C-CPE resulted in a decrease in TER. But, deletion of the 30 C-terminal amino acids of C-CPE, which is the putative binding domain for claudin, attenuated the decrease in TER values. Moreover, ablation of the 16 C-terminal amino acids of C-CPE also resulted in attenuation of the decrease in TER values. The C-terminal-deleted C-CPEs did not interact with claudin-4 or the extracellular domain 2 of claudin-4, which is the C-CPE binding site. These results suggest that the 16 C-terminal amino acids of C-CPE are responsible for the interaction of C-CPE and claudin-4 following the disruption of TJ barrier function.