Bursztajn S, DeSouza R, McPhie D L, Berman S A, Shioi J, Robakis N K, Neve R L
Department of Psychiatry and Program in Neuroscience, Harvard Medical School, Belmont, Massachusetts 02478, USA.
J Neurosci. 1998 Dec 1;18(23):9790-9. doi: 10.1523/JNEUROSCI.18-23-09790.1998.
Programmed cell death, or apoptosis, has been implicated in Alzheimer's disease (AD). DNA damage was assessed in primary cortical neurons infected with herpes simplex virus (HSV) vectors expressing the familial Alzheimer's disease (FAD) gene presenilin-1 (PS-1) or an FAD mutant of this gene, A246E. After infection, immunoreactivity for PS-1 was shown to be enhanced in infected cells. The infected cells exhibited no cytotoxicity, as evaluated by trypan blue exclusion and mitochondrial function assays. Quantitative analysis of cells that were immunohistochemically labeled using a Klenow DNA fragmentation assay or the TUNEL method revealed no enhancement of apoptosis in PS-1-infected cells. This result was confirmed using assays for chromatin condensation and for DNA fragmentation. Expression of PS-1 protected against induction of apoptosis in the cortical neurons by etoposide or staurosporine. The specificity of this phenotype was demonstrated by the fact that cortical cultures infected with recombinant HSV vectors expressing the amyloid precursor protein (APP-695) showed, in contrast, a significant increase in the number of apoptotic cells and an increase in DNA fragmentation for all parameters tested. Our results indicate that overexpression of wild-type or A246E mutant PS-1 does not enhance apoptosis in postmitotic cortical cells and suggest that the previously reported enhancement of apoptosis by presenilins may be dependent on cell type.
程序性细胞死亡，即细胞凋亡，与阿尔茨海默病（AD）有关。在用表达家族性阿尔茨海默病（FAD）基因早老素-1（PS-1）或该基因的FAD突变体A246E的单纯疱疹病毒（HSV）载体感染的原代皮质神经元中评估了DNA损伤。感染后，感染细胞中PS-1的免疫反应性增强。通过台盼蓝排斥试验和线粒体功能测定评估，感染细胞未表现出细胞毒性。使用Klenow DNA片段化试验或TUNEL方法对免疫组织化学标记的细胞进行定量分析，结果显示PS-1感染的细胞中细胞凋亡没有增强。使用染色质凝聚试验和DNA片段化试验证实了这一结果。PS-1的表达可保护皮质神经元免受依托泊苷或星形孢菌素诱导的细胞凋亡。这种表型的特异性通过以下事实得以证明：相比之下，用表达淀粉样前体蛋白（APP-695）的重组HSV载体感染的皮质培养物显示，所有测试参数的凋亡细胞数量显著增加，DNA片段化增加。我们的结果表明，野生型或A246E突变体PS-1的过表达不会增强有丝分裂后皮质细胞中的细胞凋亡，并表明先前报道的早老素诱导的细胞凋亡增强可能取决于细胞类型。
