PepT1-mediated tripeptide KPV uptake reduces intestinal inflammation
PepT1-mediated tripeptide KPV uptake reduces intestinal inflammation
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DOI：
10.1053/j.gastro.2007.10.026
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发表时间：
2008-01-01
期刊：
影响因子：
29.4
通讯作者：
Merlin, Didier
中科院分区：
文献类型：
--
作者：
Dalmasso, Guillaume;Charrier-Hisamuddin, Laetitia;Merlin, Didier
背景与目的：KPV是一种三肽（Lys-Pro-Va1），具有抗炎特性；然而，其作用机制尚不清楚。PepT1是一种二肽/三肽转运蛋白，通常在小肠中表达，在炎症性肠病（IBD）期间在结肠中诱导表达。本研究旨在探讨KPV在肠上皮和免疫细胞中的抗炎作用是否由pept1介导，以及在两种小鼠结肠炎模型中的抗炎作用。方法：人肠上皮细胞Caco2-BBE、HT29-Cl；在存在或不存在KPV的情况下，促炎细胞因子会刺激人T细胞（jurkat）。采用NF-kappa B荧光素酶基因报告基因、Western blot、实时RT-PCR和ELISA检测KPV的抗炎作用。摄取实验使用冷KPV作为PepT1放射性标记底物的竞争对手或使用[H-3]KPV来确定KPV摄取的动力学特性。研究了KPV对DSS和tnbs诱导的小鼠结肠炎的抗炎作用。将KPV添加到饮用水中，通过组织学水平和促炎细胞因子mRNA表达来评估炎症反应。结果：纳米摩尔浓度的KPV抑制NF-kappa B和MAP激酶炎症信号通路的激活，减少促炎细胞因子的分泌。我们发现KPV通过免疫细胞和肠上皮细胞中表达的PePT1起作用。此外，口服KPV可以降低DSS和tnbs诱导的结肠炎的发生率，这表明促炎细胞因子的表达降低。结论：本研究提示KPV可通过PepT1转运到细胞中，可能成为IBD的一种新的治疗药物。
Background &Aims: KPV is a tripeptide (Lys-Pro-Va1), which possesses anti-inflammatory properties; however, its mechanisms of action still remain unknown. PepT1 is a di/tripeptide transporter normally expressed in the small intestine and induced in colon during inflammatory bowel disease (IBD). The aim of this study was to 1) investigate whether the KPV anti-inflammatory effect is PepT1-mediated in intestinal epithelian and immune cells, and 2) examine the anti-inflammatory effects in two models of mice colitis. Methods: Human intestinal epithelial cells Caco2-BBE, HT29-Cl.19A, and human T cells (jurkat) were stimulated with pro-inflammatory cytokines in the present or absence of KPV. KPV anti-inflammatory effect was assessed using a NF-kappa B luciferase gene reporter, Western blot, real-time RT-PCR and ELISA. Uptake experiments were performed using cold KPV as a competitor for PepT1 radiolabelled substrate or using [H-3]KPV to determine kinetic characteristics of KPV uptake. Anti-inflammatory effect of KPV was also investigated in DSS- and TNBS-induced colitis in mice. KPV was added to drinking water and inflammation was assessed at the histologic level and by proinflammatory cytokine mRNA expression. Results: Nanomolar concentrations of KPV inhibit the activation of NF-kappa B and MAP kinase inflammatory signaling pathways, and reduce pro-inflammatory cytokine secretion. We found that KPV acts via PePT1 expressed in immune and intestinal epithelial cells. Furthermore, oral administration of KPV reduces the incidence of DSS- and TNBS-induced colitis indicated by a decrease in pro-inflammatory cytokine expression. Conclusions: This study indicates tht KPV is transported into cells by PepT1 and might be a new therapeutic agent for IBD.