Quercetin enhances epithelial barrier function and increases claudin-4 expression in Caco-2 cells
Quercetin enhances epithelial barrier function and increases claudin-4 expression in Caco-2 cells
复制标题
DOI：
10.1093/jn/138.6.1067
复制
发表时间：
2008-06-01
影响因子：
4.2
通讯作者：
Schulzke, Joerg D.
中科院分区：
文献类型：
--
作者：
Amasheh, Maren;Schlichter, Susanne;Schulzke, Joerg D.
槲皮素是最丰富的黄酮类化合物，被认为在饮食摄入后对胃肠道粘膜具有积极作用。本研究的目的是利用人结肠上皮细胞系Caco-2分析槲皮素对肠屏障功能的影响。在Ussing室中测定跨上皮电阻（R-t）、[H-3]-甘露醇、Na-22（+）和Cl-36（-）的示踪剂通量以及生电离子转运。分别用Western印迹和定量RT-PCR分析紧密连接蛋白和mRNA的表达。通过报告基因分析来分析转录调控。用激光共聚焦扫描显微镜（LSM）检测TJ蛋白的细胞分布。采用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法检测细胞凋亡率。槲皮素诱导R-t呈剂量依赖性增加，持续时间> 2d。每日添加槲皮素能够使该效果永久化，无论槲皮素是添加到顶部还是基底外侧隔室。与R-t增加平行，槲皮素诱导TJ蛋白claudin-4的强烈增加，但不诱导其他claudin。共聚焦LSM显示紧密连接蛋白-4在TJ中的定位。槲皮素对细胞凋亡率无影响。与这些变化一致，Na+和Cl-的通量，但不是甘露醇，减少。报告基因分析显示槲皮素对claudin-4转录的刺激作用。类黄酮槲皮素通过TJ蛋白claudin-4的转录表达调节来增强屏障功能，这代表了这种食物组分对肠道炎症中屏障障碍的重要保护作用。
Quercetin is the most abundant flavonoid and is assumed to have positive effects on the gastrointestinal mucosa after dietary intake. The aim of the study was to analyze the influence of quercetin on intestinal barrier function using the human colonic epithelial cell line Caco-2. Transepithelial resistance (R-t), tracer fluxes of [H-3]-mannitol, Na-22(+), and Cl-36(-) as well as electrogenic ion transport were determined in Ussing chambers. Expression of tight junction (TJ) proteins and mRNA was analyzed in Western blots and quantitative RT-PCR, respectively. Regulation of transcription was analyzed by reporter gene assay. Cellular distribution of TJ proteins was examined by confocal laser scanning microscopy (LSM). Apoptotic rate was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining. Quercetin induced a dose-dependent increase of R-t persisting for >2 d. Daily addition of quercetin was able to perpetuate the effect, which was seen whether quercetin was added apically or to the basolateral compartment. Parallel to the R-t increase, quercetin induced a strong increase of the TJ protein claudin-4 but not of other claudins. Confocal LSM showed a localization of claudin-4 in TJ. Apoptotic rate was not affected by quercetin. Consistent with these changes, fluxes of Na+ and Cl-, but not of mannitol, were reduced. Reporter gene assays revealed a stimulatory effect of quercetin on claudin-4 transcription. The flavonoid quercetin enhances barrier function via transcriptional expression regulation of the TJ protein claudin-4, which represents an important protective effect of this food component against barrier disturbance in intestinal inflammation.