Mechanisms of manganese-induced rat pheochromocytoma (PC12) cell death and cell differentiation
Mechanisms of manganese-induced rat pheochromocytoma (PC12) cell death and cell differentiation
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DOI：
10.1016/s0161-813x(01)00077-8
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发表时间：
2002-07-01
期刊：
影响因子：
3.4
通讯作者：
Garrick, MD
中科院分区：
文献类型：
--
作者：
Roth, JA;Horbinski, C;Garrick, MD
锰是一种神经毒素，长期暴露于高浓度后可导致类似帕金森病的综合征。我们的实验室一直在研究锰诱导神经元细胞死亡的机制。为了实现这一目标，我们利用大鼠嗜铬细胞瘤（PC12）细胞作为模型，因为它们具有许多与多巴胺能神经元相关的生化机制。Mn与神经生长因子（NGF）一样，可以诱导PC12细胞的神经元分化，但Mn诱导的细胞分化依赖于其与细胞表面整合素受体和基底膜蛋白、玻璃体连接蛋白或纤维连接蛋白的相互作用。与NGF类似，mn诱导的神经突生长依赖于MAP激酶、ERKI和2的磷酸化和激活（p44/42）。与NGF不同，Mn也具有细胞毒性，其IC50值与600 muM相似。虽然许多凋亡信号是由Mn打开的，但细胞死亡最终是由于线粒体功能的破坏导致ATP的损失。RT-PCR和免疫印迹研究表明，PC12细胞对锰的摄取依赖于二价金属转运体1 （DMTI）。DMTI存在于三个同工异构体中，这是由单个基因产物与两个mRNA物种中的一个在停止密码子下游含有铁反应元件（IRE）基序进行交替剪接而产生的。IRE的存在为铁反应蛋白（IRPI和2）提供了一个结合位点；这些蛋白中的任何一种结合都可以稳定DMTI mRNA，并增加+IRE形式转运蛋白的表达。铁和锰通过DMTl竞争进入PC12细胞，因此从培养基中去除铁会增强锰的毒性。DMTI （IRE）的两种异构体分布在不同的亚细胞区室中，（+/-IRE）种选择性地存在于神经元和神经元样细胞的细胞核中。(C) 2002爱思唯尔科学有限公司版权所有。
Mn is a neurotoxin that leads to a syndrome resembling Parkinson's disease after prolonged exposure to high concentrations. Our laboratory has been investigating the mechanism by which Mn induces neuronal cell death. To accomplish this, ire have utilized rat pheochromocytoma (PC12) cells as a model since they possess much of the biochemical machinery associated with dopaminergic neurons. Mn, like nerve growth factor (NGF), can induce neuronal differentiation of PC12 cells but Mn-induced cell differentiation is dependent on its interaction with the cell surface integrin receptors and basement membrane proteins, vitronectin or fibronectin. Similar to NGF Mn-induced neurtite outgrowth is dependent on the phosphorylation and activation of the MAP kinases, ERKI and 2 (p44/42). Unlike NGF, Mn is also cytotoxic having an IC50 value of similar to600 muM. Although many apoptotic signals are turned on by Mn, cell death is caused ultimately by disruption of mitochondrial function leading to loss of ATP. RT-PCR and immunoblotting studies suggest that some uptake of Mn into PC12 cells depends on the divalent metal transporter 1 (DMTI). DMTI exists in trio isoforms resulting from alternate splicing of a single gene product with one of the two mRNA species containing an iron response clement (IRE) motif downstream from the stop codon. The presence of the IRE provides a binding site for the iron response proteins (IRPI and 2); binding of either of these proteins could stabilize DMTI mRNA and would increase expression of the +IRE form of the transporter. Iron and Mn compete for transport into PC12 cells via DMTl, so removal of iron from the culture media enhances Mn toxicity. The two isoforms of DMTI ( IRE) are distributed in different subcellular compartments with the (+/-IRE) species selectively present in the nucleus of neuronal and neuronal-like cells. (C) 2002 Elsevier Science Inc. All rights reserved.