Wild-type and mutated presenilins 2 trigger p53-dependent apoptosis and down-regulate presenilin 1 expression in HEK293 human cells and in murine neurons
Wild-type and mutated presenilins 2 trigger p53-dependent apoptosis and down-regulate presenilin 1 expression in HEK293 human cells and in murine neurons
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DOI：
10.1073/pnas.062059899
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发表时间：
2002-03-19
影响因子：
11.1
通讯作者：
Checler, F
中科院分区：
文献类型：
--
作者：
da Costa, CA;Paitel, E;Checler, F
早老素1和2是两种同源蛋白，当突变时，可以解释大多数早发性阿尔茨海默病的原因。一些证据表明，在各种功能中，早老素可以调节细胞的凋亡反应。通过台盼蓝排除法、3‘-[1-(phenylamino-carbonyl)-3，4-tetrazolium]-bis(4-methoxy-6-nitro)benzene磺酸钠水合物比色法和碘化丙啶掺入流式细胞仪分析，我们证实早老素2(PS2)及其突变形式ASN-141-LLE-PS2的过表达改变了人胚胎肾293细胞的存活率。这两个亲本蛋白增加了HEK293细胞和端脑特异的小鼠神经元中对乙酰-DEVD-al敏感的caspase-3的活性，调节了Sax和bcl2的表达，并促进了细胞色素C向胞浆的移位。我们发现野生型和突变型PS2的过表达都增加了P53样免疫反应和转录活性。我们还发现，野生型和突变的PS2诱导的caspase激活可以通过p53反义方法和P53的化学抑制剂匹非菊酯-a来降低。此外，PS2基因被敲除的小鼠成纤维细胞显示出强烈的P53转录活性降低。最后，我们证实野生型和突变型PS2的过度表达伴随着内源性早老素1(PS1)表达的急剧减少。有趣的是，匹氟菊酯-a降低了内源性PS2的免疫反应性，而抑制剂则增加了PSI的表达。总之，我们的数据表明，野生型和家族性阿尔茨海默病相关的PS2通过P53依赖的机制触发细胞凋亡并下调PSI的表达。
Presenilins 1 and 2 are two homologous proteins that, when mutated, account for most early onset Alzheimer's disease. Several lines of evidence suggest that, among various functions, presenilins could modulate cell apoptotic responses. Here we establish that the overexpression of presenilin 2 (PS2) and its mutated form Asn-141-lle-PS2 alters the viability of human embryonic kidney (HEK)293 cells as established by combined trypan blue exclusion, sodium 3'-[1-(phenylamino-carbonyl)-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene sulfonic acid hydrate assay, and propidium iodide incorporation FACS analyses. The two parent proteins increase the acetyl-DEVD-al-sensitive caspase-3-like activity in both HEK293 cells and Telencephalon specific murine neurons, modulate Sax and bcl-2 expressions, and enhance cytochrome C translocation into the cytosol. We show that overexpression of both wild-type and mutated PS2 increases p53-like immunoreactivity and transcriptional activity. We also establish that wild-type- and mutated PS2-induced caspase activation is reduced by p53 antisense approach and by pifithrin-a, a chemical inhibitor of p53. Furthermore, mouse fibroblasts in which the PS2 gene has been knocked out exhibited strongly reduced p53-transcriptional activity. Finally, we establish that the overexpression of both wild-type and mutated PS2 is accompanied by a drastic reduction of endogenous presenilin 1 (PS1) expression. Interestingly, pifithrin-a diminished endogenous PS2 immunoreactivity, whereas the inhibitor increases PSI expression. Altogether, our data demonstrate that wild-type and familial Alzheimer's disease-linked PS2 trigger apoptosis and down-regulate PSI expression through p53-dependent mechanisms.