Transforming Growth Factor-β, a Whey Protein Component, Strengthens the Intestinal Barrier by Upregulating Claudin-4 in HT-29/B6 Cells
Transforming Growth Factor-β, a Whey Protein Component, Strengthens the Intestinal Barrier by Upregulating Claudin-4 in HT-29/B6 Cells
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DOI：
10.3945/jn.110.137588
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发表时间：
2011-05-01
影响因子：
4.2
通讯作者：
Schulzke, Joerg D.
中科院分区：
文献类型：
--
作者：
Hering, Nina A.;Andres, Susanne;Schulzke, Joerg D.
TGF β（亚型1-3）在肠道中具有屏障保护作用。参与调节紧密连接蛋白表达的机制知之甚少。本研究的目的是阐明TGF β依赖的保护作用，特别注意使用HT-29/B6细胞模型的紧密连接蛋白的启动子调节。此外，研究了乳清蛋白浓缩物1（WPC 1）的作用，它是人类营养中TGF β的天然来源。为此，克隆了密蛋白-4启动子并测试其活性。它表现出对TGF β 1的反式激活，当Smad-4共转染时，这种反式激活增强，表明Smad-4依赖性调节组分。启动子的缩短和突变改变并减弱了这种效应。WPC 1诱导HT-29/B6细胞单层的claudin-4蛋白水平和抗性增加。抗TGF β（1-3）抗体阻断了这些乳清蛋白的作用，表明该功能的主要部分是通过TGF β介导的。观察到这种效果的完整单层，以及当屏障功能受损的预暴露于IFN γ。总之，TGF β 1通过Smad-4依赖性和非依赖性转录调节影响claudin-4基因表达，导致屏障保护，这是一种细胞因子效应，也存在于用于肠内营养的乳清蛋白浓缩物中。J.营养141：783-789，2011.
TGF beta (isoforms 1-3) has barrier-protective effects in the intestine. The mechanisms involved in regulating tight junction protein expression are poorly understood. The aim of this study was to elucidate TGF beta-dependent protective effects with special attention to promoter regulation of tight junction proteins using the HT-29/B6 cell model. In addition, the effects of whey protein concentrate 1 (WPC1), a natural source of TGF beta in human nutrition, were examined. For this purpose, the claudin-4 promoter was cloned and tested for its activity. It exhibited transactivation in response to TGF beta 1, which was intensified when Smad-4 was cotransfected, indicating a Smad-4 dependent regulatory component. Shortening and mutation of the promoter altered and attenuated this effect. WPC1 induced an increase in the claudin-4 protein level and resistance of HT-29/B6 cell monolayers. Anti-TGF beta(1-3) antibodies blocked these whey protein effects, suggesting that a main part of this function was mediated through TGF beta. This effect was observed on intact monolayers as well as when barrier function was impaired by preexposure to IFN gamma. In conclusion, TGF beta 1 affects claudin-4 gene expression via Smad-4-dependent and -independent transcriptional regulation, resulting in barrier protection, a cytokine effect that is also found in whey protein concentrates used in enteral nutrition. J. Nutr. 141: 783-789, 2011.