Targets of Caspase-6 activity in human neurons and Alzheimer disease
Targets of Caspase-6 activity in human neurons and Alzheimer disease
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DOI：
10.1074/mcp.m800007-mcp200
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发表时间：
2008-08-01
影响因子：
7
通讯作者：
LeBlanc, Andrea C.
中科院分区：
文献类型：
--
作者：
Klaiman, Guy;Petzke, Tracy L.;LeBlanc, Andrea C.
半胱天冬酶-6活化发生在阿尔茨海默病的早期，有时先于老年人的临床表现。活性半胱天冬酶-6定位于神经炎斑块、神经纤维丝和含有本质上形态学上不凋亡的神经元的神经纤维缠结中。为了研究Caspase-6在神经元中激活的潜在后果，我们对Caspase-6介导的人类神经元蛋白裂解进行了蛋白质组学分析。用重组活性Caspase-6处理来自胞质和膜亚细胞区室的蛋白质，并通过二维凝胶电泳与未消化的蛋白质进行比较。裂解蛋白质的LC/MS/MS分析鉴定了24种不同的潜在蛋白质底物。其中，40%是细胞骨架或细胞骨架相关蛋白。我们专注于细胞骨架蛋白，因为它们对神经元的结构和功能至关重要。证实了α-微管蛋白、α-肌动蛋白-4、嗜棘蛋白和Drebocyte的半胱天冬酶-6裂解。至少一个半胱天冬酶-6切割位点被鉴定为Dreplastin、Spinophilin和α-微管蛋白。一种针对α-微管蛋白的新表位抗血清，其被胱天蛋白酶-6免疫染色的阿尔茨海默病中的神经元、神经纤维缠结、神经纤维丝和神经炎斑裂解，并与活性胱天蛋白酶-6共定位。这些结果表明，在阿尔茨海默病的早期和神经炎性激活的Caspase-6可以破坏神经元的细胞骨架网络，导致受损的神经元结构和功能的细胞死亡的情况下。这项研究为阿尔茨海默病的病理生理学提供了新的见解。
Caspase-6 activation occurs early in Alzheimer disease and sometimes precedes the clinical manifestation of the disease in aged individuals. The active Caspase-6 is localized in neuritic plaques, in neuropil threads, and in neurofibrillary tangles containing neurons that are not morphologically apoptotic in nature. To investigate the potential consequences of the activation of Caspase-6 in neurons, we conducted a proteomics analysis of Caspase-6-mediated cleavage of human neuronal proteins. Proteins from the cytosolic and membrane subcellular compartments were treated with recombinant active Caspase-6 and compared with undigested proteins by two-dimensional gel electrophoresis. LC/MS/MS analyses of the proteins that were cleaved identified 24 different potential protein substrates. Of these, 40% were cytoskeleton or cytoskeleton-associated proteins. We focused on the cytoskeleton proteins because these are critical for neuronal structure and function. Caspase-6 cleavage of alpha-Tubulin, alpha-Actinin-4, Spinophilin, and Drebrin was confirmed. At least one Caspase-6 cleavage site was identified for Drebrin, Spinophilin, and alpha-Tubulin. A neoepitope antiserum to alpha-Tubulin cleaved by Caspase-6 immunostained neurons, neurofibrillary tangles, neuropil threads, and neuritic plaques in Alzheimer disease and co-localized with active Caspase-6. These results imply that the early and neuritic activation of Caspase-6 in Alzheimer disease could disrupt the cytoskeleton network of neurons, resulting in impaired neuronal structure and function in the absence of cell death. This study provides novel insights into the pathophysiology of Alzheimer disease.