Visualization of newly deposited tau in neurofibrillary tangles and neuropil threads
Visualization of newly deposited tau in neurofibrillary tangles and neuropil threads
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DOI：
10.1097/01.jnen.0000173890.79058.1d
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发表时间：
2005-08-01
影响因子：
3.2
通讯作者：
Ihara, Y
中科院分区：
文献类型：
--
作者：
Miyasaka, T;Watanabe, A;Ihara, Y
神经纤维缠结（NFT）和神经纤维丝（NT）是阿尔茨海默病（AD）的主要标志，由微管相关蛋白tau组成，其经历了翻译后修饰，包括天冬酰胺基或天冬酰胺基残基上的脱酰胺和异构化。因为这样的修饰代表蛋白质老化，所以我们产生了2种抗体，对tau的Asp-387特异性的TM 4和对tau的isoAsp-387特异性的iD 387，以研究NFT和NT的进化。在Sarkosyl不溶性组分的Western印迹上，TM 4强烈标记成对螺旋状的亲和性-tau（PHF-tau），而iD 387优先标记PHF涂片。因此，合理的假设是，TM 4标记的tau（未修饰的tau种类）代表更近的沉积，而iD 387标记的tau（修饰的tau种类）代表更早的沉积。出乎意料的是，TM 4免疫染色甚至高度进化的NFT，表明新产生的tau蛋白的沉积持续到神经元死亡。iD 387标记了直至远端树突分支的NFT的整个轮廓，而TM 4染色定位于近端树突和神经元胞体中的NFT的特定部分。在NT中，TM 4优先标记外部部分，而iD 387强烈标记核心部分。基于TM 4阳性NFT计数和总NFT计数，我们推测人海马中的NFT以恒定的速率产生，而与疾病阶段无关。
Neurofibrillary tangles (NFTs) and neuropil threads (NTs), the major hallmark of Alzheimer disease (AD), are composed of the microtubule-associated protein tau that has undergone posttranslational modifications, including deamidation and isomerization on asparaginyl or aspartyl residues. Because such modifications represent protein aging, we generated 2 antibodies, TM4, specific for Asp-387 of tau, and iD387, specific for isoAsp-387 of tau, to investigate the evolution of NFTs and NTs. On Western blots of Sarkosyl-insoluble fractions, TM4 strongly labeled paired helical filament-tau (PHF-tau), whereas iD387 preferentially labeled PHF smear. Thus, it is reasonable to postulate that TM4-labeled tau (unmodified tau species) represents more recent deposition, and iD387-labeled tau (modified tau species) represents earlier deposition. Unexpectedly, TM4 immunostained even highly evolved NFTs, suggesting that deposition of newly produced tau continues until neuronal death. iD387 labeled the whole profile of NFTs up to distal dendritic branches, whereas TM4 staining was localized to particular portions of NFTs in proximal dendrites and neuronal perikarya. In NTs, TM4 preferentially labeled the outer portion, whereas iD387 intensely labeled the core portion. Based on TM4-positive NFT counts and total NFT counts, we speculate that NFTs in the human hippocampus are produced at a constant rate irrespective of the disease stage.