Tumor necrosis factor α decreases aquaporin 3 expression in intestinal epithelial cells through inhibition of constitutive transcription.
Tumor necrosis factor α decreases aquaporin 3 expression in intestinal epithelial cells through inhibition of constitutive transcription.
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DOI：
10.14814/phy2.13451
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发表时间：
2017-10
影响因子：
2.5
通讯作者：
MacNaughton WK
中科院分区：
文献类型：
--
作者：
Peplowski MA;Vegso AJ;Iablokov V;Dicay M;Zaheer RS;Renaux B;Proud D;Hollenberg MD;Beck PL;MacNaughton WK
肠道炎症性疾病与电解质和水的转运改变有关，导致腹泻的发生。上皮表达的水通道蛋白（AQP）在炎症中下调，尽管涉及的机制尚不清楚。我们假设肠上皮细胞中AQP 3的表达在肠道炎症中发生改变，并且这些变化由肿瘤坏死因子（TNF）α驱动。用TNF α处理人结肠腺癌（HT-29）细胞，以研究体外信号传导机制。通过真实的时间PCR和放射性标记的甘油摄取评估AQP 3表达，选择抑制剂和荧光素酶报告基因构建体用于进一步阐明细胞内信号传导。HT-29细胞经TNF α处理后AQP 3表达下调。荧光素酶报告基因构建体实验显示，TNF α下调了AQP 3启动子的组成型转录活性，抑制MEK/ERK和核因子κB（NF-κB）信号传导可防止AQP 3 mRNA表达的降低。特异性蛋白（Sp）3可抑制AQP 3的组成性表达，敲低与AQP 3启动子结合的转录因子可部分阻止TNF α诱导的AQP 3下调。TNF α通过MEK/ERK和NF-κB信号传导增强Sp3对AQP 3表达的负转录调控。类似的机制调节许多离子通道，这表明在炎症中改变离子和水运输的共同机制。
Inflammatory diseases of the gut are associated with altered electrolyte and water transport, leading to the development of diarrhea. Epithelially expressed aquaporins (AQPs) are downregulated in inflammation, although the mechanisms involved are not known. We hypothesized that AQP3 expression in intestinal epithelial cells is altered in intestinal inflammation and that these changes are driven by tumor necrosis factor (TNF) α. Human colonic adenocarcinoma (HT‐29) cells were treated with TNF α to investigate signaling mechanisms in vitro. AQP3 expression was assessed by real‐time PCR and radiolabeled glycerol uptake, with select inhibitors and a luciferase reporter construct used to further elucidate intracellular signaling. AQP3 expression was downregulated in HT‐29 cells treated with TNF α. Luciferase reporter construct experiments revealed that TNF α downregulated constitutive transcriptional activity of the AQP3 promoter, and inhibition of MEK/ERK and nuclear factor κB (NF‐κB) signaling prevented the decrease in AQP3 mRNA expression. Constitutive AQP3 expression was suppressed by specificity protein (Sp) 3, and knockdown of this transcription factor bound to the AQP3 promoter was able to partially prevent the TNF α‐induced downregulation of AQP3. TNF α signals through MEK/ERK and NF‐κB to enhance the negative transcriptional control of AQP3 expression exerted by Sp3. Similar mechanisms regulate numerous ion channels, suggesting a common mechanism by which both ion and water transport are altered in inflammation.