Suppression of matrix metalloproteinase-9 transcription by transforming growth factor-β is mediated by a nuclear factor-κB site
Suppression of matrix metalloproteinase-9 transcription by transforming growth factor-β is mediated by a nuclear factor-κB site
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DOI：
10.1042/bj20040058
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发表时间：
2004-07-15
影响因子：
4.1
通讯作者：
Chen, Y
中科院分区：
文献类型：
--
作者：
Ogawa, K;Chen, FF;Chen, Y
TGF-β（转化生长因子-β）通过调节MMP（基质金属蛋白酶）的产生在调节炎症反应和其他生物过程中起关键作用。在Mono-Mac-6和RAW264.7单核细胞/巨噬细胞中，TGF-β消除了脂多糖诱导的MMP-9酶活性和mRNA水平的增加。使用人MMP-9启动子的片段来表征其通过TGF-β信号传导的调节。在RAW264.7细胞中，TGF-β或其下游信号蛋白Smad 3（Sma和Mad-related protein 3）抑制脂多糖刺激的启动子活性。TGF-β对MMP-9启动子的抑制活性被抑制性Smad，Smad 7废除。MMP-9启动子含有推定的TIE（TGF-β抑制元件）。然而，TIE的突变或缺失对TGF-β对MMP-9转录的抑制活性都没有任何影响，表明共有TIE对于TGF-β的这种作用不是必需的。使用MMP-9启动子的一系列缺失突变体的分析显示，包含共有NF-κ B（核因子-κ B）位点的区域是启动子的基础活性和TGF-β介导的抑制所需的。假定的NF-κ B位点的突变不仅显著降低了启动子的基础转录活性，而且还消除了启动子对TGF-β的响应性。此外，含有一个拷贝的NF-κ B序列的最小启动子对TGF-β处理有反应。此外，用来自RAW264.7细胞的核提取物进行电泳迁移率变动测定，发现TGF-β处理不破坏NF-κ B p50和p65蛋白与NF-κ B序列的结合。总之，这些研究表明NF-κ B位点对于TGF-β在MMP-9转录调节中的抑制活性是必不可少的。
TGF-beta (transforming growth factor-beta) plays a critical role in modulating the inflammatory response and other biological processes through its regulation of the production of MMPs (matrix metalloproteinases). In both Mono-Mac-6 and RAW264.7 monocyte/macrophage cells, TGF-beta abrogated lipopolysaccharide-induced increases in the enzymic activity and mRNA level of MMP-9. A fragment of the human MMP-9 promoter was used to characterize its regulation by TGF-beta signalling. In RAW264.7 cells, TGF-beta or its downstream signalling protein, Smad3 (Sma- and Mad-related protein 3), inhibited lipopolysaccharide-stimulated promoter activity. The suppressive activity of TGF-beta on the MMP-9 promoter was abrogated by an inhibitory Smad, Smad7. The MMP-9 promoter contains a putative TIE (TGF-beta inhibitory element). However, neither mutation nor deletion of the TIE had any effect on the inhibitory activity of TGF-beta on MMP-9 transcription, indicating that the consensus TIE is not required for this effect of TGF-beta. Analysis using a series of deletion mutants of the MMP-9 promoter revealed that a region containing a consensus NF-kappaB (nuclear factor-kappaB) site is required for the basal activity and TGF-beta-mediated suppression of the promoter. Mutation of the putative NF-kappaB site not only markedly reduced the basal transcriptional activity of the promoter, but also abrogated the responsiveness of the promoter to TGF-beta. In addition, a minimal promoter containing one copy of the NF-kappaB sequence was responsive to TGF-beta treatment. Furthermore, an electrophoretic mobility shift assay was performed with the nuclear extracts from RAW264.7 cells, and it was found that TGF-beta treatment did not disrupt the binding of NF-kappaB p50 and p65 proteins to the NF-kappaB sequence. Taken together, these studies indicate that the NF-kappaB site is indispensable for the suppressive activity of TGF-beta in the regulation of MMP-9 transcription.