Role of inositol polyphosphates in programmed cell death
Role of inositol polyphosphates in programmed cell death
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DOI：
10.1007/s11010-009-0085-6
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发表时间：
2009-08-01
影响因子：
4.3
通讯作者：
Ali, Nawab
中科院分区：
文献类型：
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作者：
Agarwal, Rakhee;Mumtaz, Hamid;Ali, Nawab
以小鼠成骨细胞系MC 3 T3为模型，研究了多磷酸肌醇（InsPs）在诱导细胞凋亡中的作用。InsP（4）、InsP（5）和InsP（6）的细胞外给药以剂量依赖性方式增加细胞凋亡。InsP（6）的促凋亡作用强于InsP（5）和InsP（4）。采用吖啶橙子/溴化乙锭法、流式细胞术和DNA降解等方法，研究InsP（6）诱导细胞凋亡的特异性。为了研究内源性InsPs对细胞凋亡的影响，我们使用氟化钠和抗霉素A作为处理剂来操纵细胞内InsPs的水平。已知NaF通过抑制InsPs磷酸酶来增加更高InsPs的水平，这是一个被抗霉素A逆转的过程，因为InsPs激酶由于细胞ATP库的消耗而被抑制。MC 3 T3细胞的细胞凋亡以NaF剂量和时间依赖性方式诱导。在1 mM NaF下8 h内观察到约50%的细胞凋亡。与对照组相比，10 μ M抗霉素A预处理30分钟显著降低了氟化钠诱导的细胞凋亡。此外，我们还测量了AKT磷酸化、caspase-3和caspase-9裂解以及细胞色素C从线粒体释放到胞质溶胶中的变化。这些变化与类似条件下的总细胞InsPs一致。这些数据表明，氟化钠诱导的凋亡标志物的变化可能是由于增加的内源性InsPs，抗霉素A治疗部分逆转。
The role of inositol polyphosphates (InsPs) in the mediation of cellular apoptosis was investigated in mouse MC3T3 osteoblastic cell line. Extracellular administration of InsP(4), InsP(5), and InsP(6) increased apoptosis in a dose-dependent manner. InsP(6) was more potent than InsP(5) and InsP(4) in promoting apoptosis. Inositol hexasulfate (InsS(6)), a structural analog of InsP(6), was used to determine specificity of InsP(6)-induced apoptosis as measured by acridine orange/ethidium bromide, flow cytometry, and DNA degradation. In order to study the effects of endogenous InsPs on apoptosis, we used NaF and antimycin A as treatment agents to manipulate intracellular levels of InsPs. NaF is known to increase levels of higher InsPs by inhibiting InsPs phosphatases, a process that is reversed by antimycin A because InsPs kinases are inhibited as a result of depletion of cellular ATP pools. Apoptosis was induced in MC3T3 cells in a NaF dose- and time-dependent manner. Approximately 50% apoptosis was observed at 1 mM NaF in 8 h. Prior treatment with 10 mu M antimycin A for 30 min significantly reduced the NaF-induced apoptosis as compared with its control. Additionally, we measured changes in AKT phosphorylation, cleavage of caspase-3 and caspase-9, and release of cytochrome C from mitochondria into cytosol. These changes coincided with total cellular InsPs under similar conditions. The data indicated that NaF-induced changes in apoptotic markers could be due to an increased endogenous InsPs that were partially reversed by antimycin A treatment.