The essential micronutrient zinc has long been known to be a functional component of diverse structural proteins and enzymes. More recently, important roles for free or loosely bound intracellular zinc as a signaling factor have been reported. Insufficient zinc intake was shown to exacerbate symptoms in mouse models of inflammation such as experimental colitis, while zinc supplementation was found to improve intestinal barrier function. Herein, we provide evidence that intracellular zinc is essential for maintaining intestinal epithelial integrity when cells are exposed to the inflammatory cytokine Tumor Necrosis Factor (TNF)α. Using the human intestinal Caco-2/TC7 cell line as an in vitro model, we demonstrate that depletion of intracellular zinc affects TNFα-triggered signaling by shifting intestinal cell fate from survival to death. The mechanism underlying this effect was investigated. We show that TNFα promotes a zinc-dependent survival pathway that includes modulation of gene expression of transcription factors and signaling proteins. We have identified multiple regulatory steps regulated by zinc availability which include the induction of cellular Inhibitor of APoptosis (cIAP2) mRNA, possibly through activation of Nuclear Factor-Kappa B (NF-κB), as both nuclear translocation of the p65 subunit of NF-κB and up-regulation of cIAP2 mRNA were impaired following zinc depletion. Moreover, X-linked inhibitor of apoptosis protein level was profoundly reduced by zinc depletion. Our results provide a possible molecular explanation for the clinical observation that zinc supplements ameliorate Crohn's disease symptoms and decrease intestinal permeability in experimental colitis.

译文

必需微量营养素锌长期以来一直是多种结构蛋白和酶的功能成分。最近,已经报道了游离或松散结合的细胞内锌作为信号因子的重要作用。在小鼠炎症模型 (例如实验性结肠炎) 中,锌摄入不足会加剧症状,而补充锌可改善肠屏障功能。在本文中,我们提供了证据,当细胞暴露于炎性细胞因子肿瘤坏死因子 (TNF)α 时,细胞内锌对于维持肠上皮完整性至关重要。使用人肠Caco-2/TC7细胞系作为体外模型,我们证明了细胞内锌的耗竭通过将肠道细胞的命运从存活转移到死亡来影响tnf α 触发的信号传导。研究了这种作用的机制。我们表明tnf α 促进了锌依赖性的存活途径,包括转录因子和信号蛋白的基因表达的调节。我们已经确定了多个调节步骤受锌利用率的调节,包括诱导细胞凋亡抑制剂 (cIAP2) mRNA,可能是通过激活核因子 κ B (NF-κ B),因为锌耗尽后NF-κ B p65亚基的核易位和cIAP2 mRNA的上调均受损。此外,锌耗竭使X连锁凋亡抑制剂蛋白水平大大降低。我们的结果为临床观察提供了可能的分子解释,即锌补充剂可改善实验性结肠炎的克罗恩病症状并降低肠通透性。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录