大鼠小肠中肽转运体1（PepT1）对5-氟尿嘧啶诱导损伤的反应调节

Regulation of the PepT1 peptide transporter in the rat small intestine in response to 5-fluorouracil-induced injury.

作者信息

Tanaka H, Miyamoto K I, Morita K, Haga H, Segawa H, Shiraga T, Fujioka A, Kouda T, Taketani Y, Hisano S, Fukui Y, Kitagawa K, Takeda E

机构信息

Department of Clinical Nutrition, School of Medicine, Tokushima University, Tokushima, Japan.

出版信息

Gastroenterology. 1998 Apr;114(4):714-23. doi: 10.1016/s0016-5085(98)70585-2.

DOI:10.1016/s0016-5085(98)70585-2

PMID:9516392

Abstract

BACKGROUND & AIMS: The oligopeptide transport system of the small intestine is resistant to mucosal injury. The mechanism of this resistance was investigated by examining the activity level and expression of the peptide transporter PepT1 in the intestine of rats treated with 5-fluorouracil.

METHODS

The expression and localization of PepT1 were examined by immunoblot analysis of brush border membrane vesicles and immunohistochemical analysis of intestinal sections with PepT1-specific rabbit polyclonal antibodies. Also, Northern blot analysis was used for the expression of PepT1 messenger RNA (mRNA).

RESULTS

Although the amounts of sucrase and an Na+-dependent glucose transporter protein in intestinal vesicles decreased markedly after 5-fluorouracil treatment, the amount of PepT1 protein remained largely unaffected. Immunohistochemical analysis also showed that the PepT1 immunoreactivity level was preserved in the brush border membrane of the remaining villi of 5-fluorouracil-treated rats. Levels of amino acid, glucose, and phosphate transporter mRNAs were profoundly depressed in 5-fluorouracil-treated animals, whereas the level of PepT1 mRNA conversely increased.

CONCLUSIONS

The resistance of intestinal peptide transport to tissue injury may be attributable to increased synthesis of PepT1 rather than to a change in the kinetic properties of the residual absorbing cells.

摘要

背景与目的

小肠的寡肽转运系统对黏膜损伤具有抗性。通过检测用5-氟尿嘧啶处理的大鼠肠道中肽转运体PepT1的活性水平和表达情况，研究了这种抗性的机制。

方法

采用针对PepT1的兔多克隆抗体，通过对刷状缘膜囊泡进行免疫印迹分析以及对肠道切片进行免疫组织化学分析，来检测PepT1的表达和定位。此外，利用Northern印迹分析检测PepT1信使核糖核酸（mRNA）的表达。

结果

尽管5-氟尿嘧啶处理后肠道囊泡中蔗糖酶和钠依赖性葡萄糖转运蛋白的量显著减少，但PepT1蛋白的量基本未受影响。免疫组织化学分析还显示，在5-氟尿嘧啶处理的大鼠剩余绒毛的刷状缘膜中，PepT1免疫反应性水平得以保留。在5-氟尿嘧啶处理的动物中，氨基酸、葡萄糖和磷酸盐转运体mRNA的水平大幅降低，而PepT1 mRNA的水平则相反升高。