PTEN: A crucial mediator of mitochondria-dependent apoptosis
PTEN: A crucial mediator of mitochondria-dependent apoptosis
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DOI：
10.1007/s10495-006-3714-5
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发表时间：
2006-02
期刊：
影响因子：
7.2
通讯作者：
Yuan Zhu;Patrick Hoell;B. Ahlemeyer;Josef Krieglstein
中科院分区：
文献类型：
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作者：
Yuan Zhu;Patrick Hoell;B. Ahlemeyer;Josef Krieglstein
10号染色体上缺失的磷酸酶和张力蛋白同源物（phosphatase and tensin homologue deleted on chromosome 10，PTEN）在多种肿瘤中的突变引起了广泛关注，研究其在肿瘤发生中的作用。PTEN作为一种重要的肿瘤抑制因子，其促凋亡作用与其拮抗PI 3 K/Akt信号通路有关。然而，较少的数据是关于其在神经退行性病变中的作用，其中凋亡过程也参与。本研究旨在探讨PTEN在神经细胞凋亡中的作用及其机制。使用原代大鼠海马培养物，staurosporine（STS，100 nM）诱导的时间依赖性细胞凋亡，伴随着显着的生产活性氧（ROS），细胞色素释放和激活caspase 9和3。而在STS刺激后0.5 ~ 24 h，PTEN的表达、磷酸化的PTEN和磷酸化的Akt水平均无明显变化，提示PTEN的蛋白水平和磷酸化状态与细胞凋亡的进程无关。有趣的是，免疫染色显示，从2到8小时后加入STS的PTEN细胞内的点状分布。双标记和蛋白质印迹的线粒体部分证明了线粒体的位置和积累的PTEN，分别与STS挑战后。此外，我们首次提供证据表明，PTEN与Bax在STS的存在和不存在。当PTEN被反义寡核苷酸敲低时，STS诱导的海马细胞ROS水平的升高、细胞色素c的释放和caspase 3的激活均被抑制。此外，敲低PTEN显著保护海马细胞免于凋亡损伤。这些结果表明，PTEN是一个重要的介导剂的依赖性细胞凋亡，因此可能成为一个分子靶点，为干预神经退行性疾病。
The highly frequent mutation of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in various cancers has attracted much attention to study its role in tumorigenesis. As an important tumor suppressor, the pro-apoptotic function of PTEN has been linked to its capacity antagonizing the PI3K/Akt signaling pathway. However, less data are available concerning its role in neurodegeneration in which apoptotic processes are also involved. In the present study, we attempted to study the role and the underlying mechanism of PTEN in neuronal apoptosis. Using primary rat hippocampal cultures, staurosporine (STS, 100 nM) induced a time-dependent apoptosis, accompanied by a marked production of reactive oxygen species (ROS), release of cytochromecand activation of caspase 9 and 3. However, the expression of PTEN, and the levels of phospho-PTEN and phospho-Akt were not changed at all time points tested (0.5–24 h) after STS stimulation, suggesting that the protein level as well as the phosphorylation status of PTEN were not related to the procession of apoptosis. Interestingly, immunostaining revealed a punctate intracellular distribution of PTEN from 2 to 8 h after adding STS. Double labeling and Western blotting of mitochondrial fraction demonstrated a mitochondrial location and accumulation of PTEN, respectively, after challenging with STS. Furthermore, we provide evidence for the first time that PTEN was associated with Bax in the absence and the presence of STS. Of note, the STS-induced marked increase in the cellular ROS level, release of cytochromecand activation of caspase 3 were inhibited in cultured hippocampal cells when PTEN was knocked down by a specific antisense. Moreover, knockdown of PTEN significantly protected hippocampal cells from apoptotic damage. These findings demonstrated that PTEN is a crucial mediator of mitochondria-dependent apoptosis, and thus could become a molecular target for interfering with neurodegenerative diseases.