Serum amyloid A activates NF-κB and proinflammatory gene expression in human and murine intestinal epithelial cells
Serum amyloid A activates NF-κB and proinflammatory gene expression in human and murine intestinal epithelial cells
复制标题
DOI：
10.1002/eji.200425688
复制
发表时间：
2005-03-01
影响因子：
5.4
通讯作者：
Jobin, C
中科院分区：
文献类型：
--
作者：
Jijon, HB;Madsen, KL;Jobin, C
血清淀粉样蛋白A（SAA）是一种急性时相蛋白，其水平与炎症性肠病的疾病活动呈正相关。在这项研究中，我们研究了SAA对肠上皮细胞（IEC）中NF-κ B B信号传导和促炎基因表达的影响。用重组SAA刺激人HT-29和Caco-2单层细胞，并测量NF-κ B B活化/NF-κ B依赖性基因表达。利用腺病毒显性失活突变体I κ B-α（Ad 5 I κ BAA）来确定NF-κ B信号通路对SAA依赖性基因表达的贡献。将来自kappa B-EGFP转基因小鼠的肠外植体和原代IEC暴露于SAA，并测量NF-κ B依赖性增强的绿色荧光蛋白（EGFP）荧光。SAA诱导HT-29细胞中I κ B-α降解、Re 1 A丝氨酸536（S536）磷酸化、NF-κ B转录活性、RelA募集至IL-8基因启动子和内源性基因（IL-8、考克斯-2）表达。此外，Ad 5 I kappa BAA消除SAA诱导的Re 1 A核转位、NF-κ B转录活性和IL-8基因表达。SAA依赖的IL-8基因表达需要激活HT-29细胞中的MAPK ERK、p38和JNK。最后，SAA诱导从kappa B-EGFP转基因小鼠分离的肠外植体中的EGFP表达，并增强原代IEC中的Re 1 A和I kappa B α磷酸化。这表明SAA可能通过其激活IEC中促炎信号传导的能力参与炎症过程。
Serum amyloid A (SAA) is an acute-phase protein whose levels positively correlate with disease activity in inflammatory bowel diseases. In this study we investigated the impact of SAA on NF-kappa B signaling and proinflammatory gene expression in intestinal epithelial cells (IEC). Human HT-29 and Caco-2 monolayers were stimulated with recombinant SAA and NF-kappa B activation/NF-kappa B-dependent gene expression measured. Adenoviral dominant negative mutants I kappa B-alpha (Ad5I kappa BAA) were utilized to determine the contribution of NF-kappa B signaling pathway to SAA-dependent gene expression. Intestinal explant and primary IEC derived from kappa B-EGFP transgenic mice were exposed to SAA and NF-kappa B-dependent enhanced green fluorescent protein (EGFP) fluorescence measured. SAA induced I kappa B-alpha degradation, Re1A serine 536 (S536) phosphorylation, NF-kappa B transcriptional activity, RelA recruitment to the IL-8 gene promoter and endogenous gene expression (IL-8, COX-2) in HT-29 cells. Further, Ad5I kappa BAA abrogated SAA-induced Re1A nuclear translocation, NF-kappa B transcriptional activity and IL-8 gene expression. SAA-dependent IL-8 gene expression required activation of the MAPK ERK, p38 and JNK in HT-29 cells. Finally, SAA induced EGFP expression in intestinal explants isolated from kappa B-EGFP transgenic mice and enhanced Re1A and I kappa B alpha phosphorylation in primary IEC. This indicates that SAA potentially participate in the inflammatory process by virtue of its ability to activate proinflammatory signaling in IEC.