Generation of aberrant forms of DFF40 concurrent with caspase-3 activation during acute and chronic liver injury in rats.
Generation of aberrant forms of DFF40 concurrent with caspase-3 activation during acute and chronic liver injury in rats.
复制标题
大鼠急性和慢性肝损伤期间 DFF40 异常形式的产生与 caspase-3 激活同时发生。
DOI：
10.1016/j.bbrc.2006.09.068
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发表时间：
2006
影响因子：
3.1
通讯作者：
Svetlov,StanislavI
中科院分区：
文献类型：
--
作者：
Xiang,Yiwen;Johnson,ErikA;Zhang,Chun;Huang,Guangling;Hayes,RonaldL;Wang,KevinKW;Svetlov,StanislavI
DNA片段化因子（DFF）形成由核酸酶DFF 40/CAD和抑制性伴侣DFF 45/ICAD组成的蛋白质复合物。虽然活化的半胱天冬酶-3已被证明可以切割DFF复合物，释放活性DFF 40和DNA片段，但在肝损伤伴随大量凋亡期间DFF周转的器官特异性机制尚不清楚。在这项研究中，我们研究了DFF 40免疫阳性蛋白在两种模型的肝损伤大鼠：急性缺血/再灌注（I/R）和慢性酒精管理。我们发现，DFF 40样蛋白在完整的大鼠肝脏中主要以52 kDa的蛋白质形式存在。肝I/R诱导的caspase-3活化和DFF 40阳性蛋白片段（40和20 kDa）的时间依赖性蓄积，最可能是通过重组caspase-3体外消化完整肝组织证明的特异性caspase-3裂解。此外，用DFF 40免疫沉淀，然后用活性半胱天冬酶-3抗体进行Western印迹，揭示了在DFF 40免疫阳性的20 kDa蛋白中存在活性半胱天冬酶-3。大鼠慢性酒精给药也导致DFF 40蛋白的剂量依赖性片段化，类似于I/R损伤。总的来说，这些数据表明，DFF 40免疫阳性蛋白存在于肝脏中作为不同的，组织特异性的分子形式，可以处理的半胱天冬酶-3在急性和慢性肝损伤。
DNA fragmentation factors (DFF) form protein complexes consisting of nuclease DFF40/CAD and inhibitory chaperon DFF45/ICAD. Although activated caspase-3 has been shown to cleave DFF complexes with the release of active DFF40 and DNA fragmentation, the organ-specific mechanisms of DFF turnover during liver injury accompanied by massive apoptosis are unclear. In this study, we investigated hepatic profile of DFF40-immunopositive proteins in two models of liver injury in rats: acute ischemia/reperfusion (I/R) and chronic alcohol administration. We show that DFF40-like proteins occur in intact rat liver mainly as a 52kDa protein. Hepatic I/R-induced caspase-3 activation and a time-dependent accumulation of DFF40-positive protein fragments (40 and 20kDa), most likely via specific caspase-3 cleavage as evidenced by in vitro digestion of intact liver tissue with recombinant caspase-3. In addition, immunoprecipitation with DFF40 followed by Western blot with active caspase-3 antibody revealed the presence of active caspase-3 in DFF40-immunopositive 20kDa proteins. Chronic alcohol administration in rats also resulted in a dose-dependent fragmentation of DFF40 proteins similar to I/R injury. Collectively, these data demonstrate that DFF40 immunopositive proteins exist in the liver as distinct, tissue-specific molecular forms that may be processed by caspase-3 during both acute and chronic liver injury.