野生型 CFTR 的表达抑制 NF-κB 驱动的炎症信号转导。
Expression of wild-type CFTR suppresses NF-kappaB-driven inflammatory signalling.
机构信息
Division of Medical Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK.
出版信息
PLoS One. 2010 Jul 14;5(7):e11598. doi: 10.1371/journal.pone.0011598.
BACKGROUND
Mutation of the cystic fibrosis transmembrane-conductance regulator (CFTR) causes cystic fibrosis (CF) but not all CF aspects can easily be explained by deficient ion transport. CF-inflammation provides one example but its pathogenesis remains controversial. Here, we tested the simple but fundamental hypothesis that wild-type CFTR is needed to suppress NF-kappaB activity.
METHODOLOGY/PRINCIPAL FINDINGS: In lung epithelial (H441) and engineered (H57) cell lines; we report that inflammatory markers are significantly suppressed by wild-type CFTR. Transient-transfection of wild-type CFTR into CFTR-naïve H441 cells, dose-dependently down-regulates both basal and Tumour Necrosis Factor-alpha evoked NF-kappaB activity when compared to transfection with empty vector alone (p<0.01, n>5). This effect was also observed in CFTR-naïve H57-HeLa cells which stably express a reporter of NF-kappaB activity, confirming that the CFTR-mediated repression of inflammation was not due to variable reporter gene transfection efficiency. In contrast, H57 cells transfected with a control cyano-fluorescent protein show a significantly elevated basal level of NF-kappaB activity above control. Initial cell seeding density may be a critical factor in mediating the suppressive effects of CFTR on inflammation as only at a certain density (1x10(5) cells/well) did we observe the reduction in NF-kappaB activity. CFTR channel activity may be necessary for this suppression because the CFTR specific inhibitor CFTR(inh172) significantly stimulates NF-kappaB activity by approximately 30% in CFTR expressing 16HBE14o- cells whereas pharmacological elevation of cyclic-AMP depresses activity by approximately 25% below baseline.
CONCLUSIONS/SIGNIFICANCE: These data indicate that CFTR has inherent anti-inflammatory properties. We propose that the hyper-inflammation found in CF may arise as a consequence of disrupted repression of NF-kappaB signalling which is normally mediated by CFTR. Our data therefore concur with in vivo and in vitro data from Vij and colleagues which highlights CFTR as a suppressor of basal inflammation acting through NF-kappaB, a central hub in inflammatory signalling.
背景
囊性纤维化跨膜电导调节因子 (CFTR) 的突变导致囊性纤维化 (CF)，但并非 CF 的所有方面都可以很容易地用离子转运缺陷来解释。CF 炎症就是一个例子，但它的发病机制仍存在争议。在这里，我们测试了一个简单但基本的假设，即野生型 CFTR 是抑制 NF-κB 活性所必需的。
方法/主要发现：在肺上皮 (H441) 和工程 (H57) 细胞系中；我们报告说，炎症标志物显著受野生型 CFTR 的抑制。与单独转染空载体相比，将野生型 CFTR 瞬时转染到 CFTR 未成熟的 H441 细胞中，可剂量依赖性地下调基础和肿瘤坏死因子-α诱导的 NF-κB 活性 (p<0.01，n>5)。在稳定表达 NF-κB 活性报告基因的 CFTR 未成熟 H57-HeLa 细胞中也观察到了这种效应，证实 CFTR 介导的炎症抑制不是由于报告基因转染效率的变化。相比之下，转染对照氰基荧光蛋白的 H57 细胞显示出明显高于对照的基础 NF-κB 活性水平升高。初始细胞接种密度可能是介导 CFTR 对炎症抑制作用的关键因素，因为只有在一定密度（1x10(5) 个细胞/孔）下，我们才观察到 NF-κB 活性的降低。CFTR 通道活性可能是这种抑制所必需的，因为 CFTR 特异性抑制剂 CFTR(inh172) 可使 CFTR 表达的 16HBE14o-细胞中的 NF-κB 活性显著增加约 30%，而药理学升高环磷腺苷可使活性降低约 25%，低于基线。
结论/意义：这些数据表明 CFTR 具有内在的抗炎特性。我们提出，CF 中发现的过度炎症可能是由于 NF-κB 信号的抑制被破坏而引起的，而 NF-κB 信号的抑制通常是由 CFTR 介导的。我们的数据因此与 Vij 及其同事的体内和体外数据一致，该数据强调 CFTR 作为 NF-κB 的抑制子，通过 NF-κB 发挥作用，NF-κB 是炎症信号的中心枢纽。
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