Degradation of myosin light chain in isolated rat hearts subjected to ischemia-reperfusion injury - A new intracellular target for matrix metalloproteinase-2
Degradation of myosin light chain in isolated rat hearts subjected to ischemia-reperfusion injury - A new intracellular target for matrix metalloproteinase-2
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DOI：
10.1161/circulationaha.104.531616
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发表时间：
2005-07-26
期刊：
影响因子：
37.8
通讯作者：
Schulz, R
中科院分区：
文献类型：
--
作者：
Sawicki, G;Leon, H;Schulz, R
背景-基质金属蛋白酶-2（MMP-2）参与缺血再灌注（I/R）损伤引起的心功能障碍。MMP-2不仅重塑细胞外基质，而且通过降解肌钙蛋白I在I/R中在细胞内起作用。是否其他细胞内的目标存在MMP-2在I/R.Methods和结果-离体大鼠心脏缺血20分钟，再灌注30分钟是未知的。MMP抑制剂邻菲咯啉或强力霉素可减弱心脏机械功能的受损恢复。有氧灌注心脏（对照）或I/R损伤（存在或不存在MMP抑制剂）的匀浆的定量2D电泳显示3种低分子量蛋白质，其水平在I/R损伤后显著增加，并通过MMP抑制剂标准化至对照水平。质谱分析鉴定了所有3种蛋白质为肌球蛋白轻链1的片段，其具有MMP-2的理论切割识别序列，并且在体外被其快速降解。用免疫金电镜、明胶酶谱法和免疫沉淀法观察I/R心脏中MMP-2与粗肌丝的关系。MMP-2被发现切割肌球蛋白轻链1之间的酪氨酸189和谷氨酰胺190在C terminal.Conclusions -我们的研究结果表明，肌球蛋白轻链1是另一种新的基质MMP-2在心肌细胞和它的降解可能有助于收缩功能障碍导致I/R损伤的心脏。
Background - Matrix metalloproteinase-2 (MMP-2) contributes to cardiac dysfunction resulting from ischemia-reperfusion (I/R) injury. MMP-2 not only remodels the extracellular matrix but also acts intracellularly in I/R by degrading troponin I. Whether other intracellular targets exist for MMP-2 during I/R is unknown.Methods and Results - Isolated rat hearts were subjected to 20 minutes of ischemia and 30 minutes of reperfusion. The impaired recovery of mechanical function of the heart was attenuated by the MMP inhibitors o-phenanthroline or doxycycline. Quantitative 2D electrophoresis of homogenates of aerobically perfused hearts (control) or those subjected to I/R injury (in the presence or absence of MMP inhibitors) showed 3 low-molecular-weight proteins with levels that were significantly increased upon I/R injury and normalized to control levels by MMP inhibitors. Mass spectrometry analysis identified all 3 proteins as fragments of myosin light chain 1, which possesses theoretical cleavage recognition sequences for MMP-2 and is rapidly degraded by it in vitro. The association of MMP-2 with the thick myofilament in fractions prepared from I/R hearts was observed with immunogold electron microscopy, gelatin zymography for MMP-2 activity, and immunoprecipitation. MMP-2 was found to cleave myosin light chain 1 between tyrosine 189 and glutamine 190 at the C terminus.Conclusions - Our results demonstrate that myosin light chain 1 is another novel substrate for MMP-2 in the cardiomyocyte and that its degradation may contribute to contractile dysfunction resulting from I/R injury to the heart.