Abnormal intracellular trafficking of high affinity nerve growth factor receptor, Trk, in stable transfectants expressing presenilin 1 protein
Abnormal intracellular trafficking of high affinity nerve growth factor receptor, Trk, in stable transfectants expressing presenilin 1 protein
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DOI：
10.1016/j.molbrainres.2005.02.018
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发表时间：
2005-06-13
期刊：
影响因子：
--
通讯作者：
Yamamoto, H
中科院分区：
文献类型：
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作者：
Hamano, T;Mutoh, T;Yamamoto, H
阿尔茨海默病（AD）的发病机制目前被认为与A沉积和氧化应激密切相关，但这些因素如何导致神经元功能障碍和细胞死亡尚不清楚。早老素I （PSI）基因突变是早发性家族性AD （FAD）的致病基因，原因是致病性a142肽的过量产生和沉积。我们在此报道了PSI cDNA稳定转染SH-SY5Y神经母细胞瘤细胞后PSI蛋白的过表达对高亲和神经生长因子受体Trk功能的分子影响，Trk是神经元存活和分化所必需的。我们检测了这些突变体对氧化应激的敏感性，发现与模拟转染的克隆相比，突变体（1143T）表达psi的克隆对氧化应激诱诱剂过氧化氢处理的易感性最高，而野生表达psi的细胞对过氧化氢处理的易感性低于突变体PS1转染的细胞。由于已知神经生长因子（NGF）可以保护神经元细胞免受氧化应激诱导的细胞死亡，因此我们研究了这些转染物中NGF- trk介导的细胞内信号通路。在野生和突变PSI cdna转染的细胞中，NGF没有引起Trk的自磷酸化反应，尽管它们的酪氨酸磷酸化的基础水平高于模拟转染的细胞。免疫细胞化学和亚细胞分离研究表明，在psi过表达的克隆中，无论野生型还是突变型，大多数Trk蛋白都异常地位于细胞质和细胞核中。这些结果强烈提示PSI蛋白的表达水平与trk依赖性神经保护胞内信号通路存在串扰。(c) 2005 Elsevier B.V.版权所有
The pathogenesis of Alzheimer's disease (AD) is now thought to be tightly linked to A deposition and oxidative stress, but it is still unknown how these factors result in neuronal dysfunction and cell death. Mutations of presenilin I (PSI) gene are the causative gene for early onset familial AD (FAD) due to the overproduction and deposition of pathogenic A 142 peptides. We report here the molecular influences of the overexpression of PSI protein by stable transfection of PSI cDNA into SH-SY5Y neuroblastoma cells on the function of high affinity nerve growth factor receptor, Trk, that is essential for neuronal survival and differentiation. We examined the sensitivity of these transfectants to oxidative stress and found that mutant (1143T) PSI-expressing clones showed the highest vulnerability to an oxidative stress inducer, hydrogen peroxide treatment compared with that of mock-transfected clones, whereas wild PSI-expressing cells were less vulnerable to the treatment than mutant PS1 transfectants. Because nerve growth factor (NGF) is known to protect neuronal cells from oxidative stress-induced cell death, we examined the NGF-Trk-mediated intracellular signaling pathway in these transfectants. In the wild and mutant PSI cDNA-transfected cells, NGF did not elicit the autophosphorylation response of Trk, although their basal levels of tyrosine phosphorylation were higher than those of mock-transfected cells. Immunocytochemical and subcellular fractionation studies revealed that most of Trk proteins are abnormally located in the cytoplasm as well as in the nucleus in PSI-overexpressing clones irrespective of wild and mutant forms. These results strongly indicate that the expression level of PSI protein has a cross talk with the Trk-dependent neuroprotective intracellular signaling pathway. (c) 2005 Elsevier B.V. All rights reserved.