Intronic regulation of matrix metalloproteinase-2 revealed by in vivo transcriptional analysis in ischemia
Intronic regulation of matrix metalloproteinase-2 revealed by in vivo transcriptional analysis in ischemia
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DOI：
10.1073/pnas.0508085102
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发表时间：
2005-11-08
影响因子：
11.1
通讯作者：
Sarkar, R
中科院分区：
文献类型：
--
作者：
Lee, JG;Dahi, S;Sarkar, R
基质金属蛋白酶-2 （Matrix metalloproteinase-2, MMP-2）在血管生成和动脉生成中起着至关重要的作用，这两个过程对缺血后组织灌注的恢复至关重要。组织缺血时MMP-2表达增加，但其机制尚不清楚。我们利用多种MMP-2- lacz报告小鼠和染色质免疫沉淀研究了MMP-2基因在后肢缺血模型中的转录激活。后肢缺血后MMP-2活性和mRNA升高。靶向缺失MMP-2的小鼠灌注恢复受损，肢体坏疽发生率高，表明MMP-2在缺血诱导的血运重建中起关键作用。缺血诱导c-Fos、c-Jun、JunB、FosB和Fra2与MMP-2启动子中存在的非典型活化蛋白1 （AP-1）位点的表达和结合，并降低转录抑制因子JunD的结合。缺血还激活了p53与邻近增强子位点（RE-1）的表达和结合，并增加了活化t细胞-c2与第一内含子内一致序列的核因子的表达和结合。在体内，删除启动子的5' AP-1/RE-1区域或替换第一个内含子可消除缺血诱导的MMP-2转录。因此，AP-1转录因子和活化t细胞-c2核因子的内含子激活协同作用，驱动缺血诱导的MMP-2转录。这些发现确定了MMP-2在缺血诱导的血运重建中的关键作用，并确定了MMP-2基因中先前未被表征的调控元件和组织缺血后体内MMP-2激活所需的同源转录因子。
Matrix metalloproteinase-2 (MMP-2) plays an essential role in angiogenesis and arteriogenesis, two processes critical to restoration of tissue perfusion after ischemia. MMP-2 expression is increased in tissue ischemia, but the responsible mechanisms remain unknown. We studied the transcriptional activation of the MMP-2 gene in a model of hindlimb ischemia by using various MMP-2-lacZ reporter mice and chromatin immunoprecipitation. MMP-2 activity and mRNA were increased after hindlimb ischemia. Mice with targeted deletion of MMP-2 had impaired restoration of perfusion and a high incidence of limb gangrene, indicating that MMP-2 plays a critical role in ischemia-induced revascularization. Ischemia induced the expression and binding of c-Fos, c-Jun, JunB, FosB, and Fra2 to a noncanonical activating protein-1 (AP-1) site present in the MMP-2 promoter and decreased binding of the transcriptional repressor JunD. Ischemia also activated the expression and binding of p53 to an adjacent enhancer site (RE-1) and increased expression and binding of nuclear factor of activated T-cells-c2 to consensus sequences within the first intron. Deletion of either the 5' AP-1/RE-1 region of the promoter or substitution of the first intron abolished ischemia-induced MMP-2 transcription in vivo. Thus, AP-1 transcription factors and intronic activation by nuclear factor of activated T-cells-c2 act in concert to drive ischemia-induced MMP-2 transcription. These findings define a critical role for MMP-2 in ischemia-induced revascularization and identify both previously uncharacterized regulatory elements within the MMP-2 gene and the cognate transcription factors required for MMP-2 activation in vivo after tissue ischemia.