Butyrate transcriptionally enhances peptide transporter PepT1 expression and activity.
Butyrate transcriptionally enhances peptide transporter PepT1 expression and activity.
复制标题
DOI：
10.1371/journal.pone.0002476
复制
发表时间：
2008-06-25
期刊：
影响因子：
3.7
通讯作者：
Merlin D
中科院分区：
文献类型：
--
作者：
Dalmasso G;Nguyen HT;Yan Y;Charrier-Hisamuddin L;Sitaraman SV;Merlin D
PepT 1是一种肠上皮顶端二/三肽转运蛋白，通常在小肠中表达，并在慢性炎症期间在结肠中诱导表达。本研究旨在研究丁酸盐对PepT 1的调节作用，丁酸盐是一种短链脂肪酸，由肠道细菌产生并积累在发炎的结肠细胞内。我们发现丁酸盐处理人肠上皮Caco 2-BBE细胞以剂量和时间依赖性方式增加人PepT 1（hPepT 1）启动子活性，在用5 mM丁酸盐处理24 h的细胞中观察到最大活性。在此条件下，hPepT 1启动子活性，mRNA和蛋白质表达水平分别通过荧光素酶测定，实时RT-PCR和Western blot进行评估。hPepT 1转运活性相应地增加了约2.5倍。丁酸盐没有改变hPepT 1 mRNA的半衰期，表明丁酸盐在转录水平上起作用。分子生物学分析表明，Cdx 2是丁酸诱导的Caco 2-BBE细胞hPepT 1表达和活性增加的最重要的转录因子。丁酸激活的Cdx 2结合hPepT 1启动子证实了凝胶位移和染色质免疫沉淀。此外，过表达Cdx 2的Caco 2-BBE细胞表现出比野生型细胞更高的hPepT 1表达水平。最后，用5 mM丁酸盐添加到饮用水中治疗小鼠24 h，增加结肠PepT 1 mRNA和蛋白质表达水平，以及增强结肠顶膜囊泡中PepT 1转运活性。总的来说，我们的研究结果表明，丁酸盐增加结肠上皮细胞中PepT 1的表达和活性，这为慢性炎症期间PepT 1的调节提供了新的理解。
PepT1, an intestinal epithelial apical di/tripeptide transporter, is normally expressed in the small intestine and induced in colon during chronic inflammation. This study aimed at investigating PepT1 regulation by butyrate, a short-chain fatty acid produced by commensal bacteria and accumulated inside inflamed colonocyte. We found that butyrate treatment of human intestinal epithelial Caco2-BBE cells increased human PepT1 (hPepT1) promoter activity in a dose- and time-dependent manner, with maximal activity observed in cells treated with 5 mM butyrate for 24 h. Under this condition, hPepT1 promoter activity, mRNA and protein expression levels were increased as assessed by luciferase assay, real-time RT-PCR and Western blot, respectively. hPepT1 transport activity was accordingly increased by ∼2.5-fold. Butyrate did not alter hPepT1 mRNA half-life indicating that butyrate acts at the transcriptional level. Molecular analyses revealed that Cdx2 is the most important transcription factor for butyrate-induced increase of hPepT1 expression and activity in Caco2-BBE cells. Butyrate-activated Cdx2 binding to hPepT1 promoter was confirmed by gel shift and chromatin immunoprecipitation. Moreover, Caco2-BBE cells overexpressing Cdx2 exhibited greater hPepT1 expression level than wild-type cells. Finally, treatment of mice with 5 mM butyrate added to drinking water for 24 h increased colonic PepT1 mRNA and protein expression levels, as well as enhanced PepT1 transport activity in colonic apical membranes vesicles. Collectively, our results demonstrate that butyrate increases PepT1 expression and activity in colonic epithelial cells, which provides a new understanding of PepT1 regulation during chronic inflammation.
登录
查看更多内容
影响因子：
24.5
作者：
Ahmad, MS;Krishnan, S;Murthy, SN
通讯作者：
Murthy, SN
影响因子：
6.4
作者：
GAMET, L;DAVIAUD, D;MURAT, JC
通讯作者：
MURAT, JC
影响因子：
15.9
作者：
Merlin, D;Steel, A;Madara, JL
通讯作者：
Madara, JL
影响因子：
29.4
作者：
CLAUSEN, MR;MORTENSEN, PB
通讯作者：
MORTENSEN, PB
DOI：
10.1152/ajpgi.2001.281.4.g947
发表时间：
2001-10-01
影响因子：
4.5
作者：
Kiela, PR;Hines, ER;Ghishan, FK
通讯作者：
Ghishan, FK