Diisopropylfluorophosphate Impairs the Transport of Membrane-Bound Organelles in Rat Cortical Axons
Diisopropylfluorophosphate Impairs the Transport of Membrane-Bound Organelles in Rat Cortical Axons
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DOI：
10.1124/jpet.115.230839
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发表时间：
2016-03-01
影响因子：
3.5
通讯作者：
Terry, Alvin V., Jr.
中科院分区：
文献类型：
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作者：
Gao, Jie;Naughton, Sean X.;Terry, Alvin V., Jr.
有机磷（OP）的广泛使用是一个持续的环境健康问题，由于OP相关的神经异常的多个报告。有机磷农药的急性毒性机制被认为是抑制乙酰胆碱酯酶，但越来越多的证据表明，这可能不能解释有机磷农药的所有长期神经毒性效应。在以前的实验（使用离体和体外模型系统）中，我们观察到杀虫剂OP毒死蜱损害轴突中的囊泡和线粒体的运动。在这里，使用延时成像技术，我们评估了OP-神经毒剂二异丙基氟磷酸盐（DFP）在广泛的浓度范围内（亚纳摩尔至微摩尔）对膜结合细胞器（MBO）的快速轴突运输的影响，这些细胞器含有用荧光标记物Dendra 2（APPDendra 2）标记的淀粉样前体蛋白（APP）。暴露于DFP和阳性对照化合物秋水仙碱1小时和24小时均导致MBO的顺行和逆行运动速度降低，静止MBO的数量增加。这些作用发生在皮摩尔（100 pM）至低纳摩尔（0.1 nM）浓度下，与受损的细胞活力或细胞骨架损伤无关。此外，DFP对轴突运输的影响发生在不抑制AChE活性的浓度下，并且它们不被胆碱能受体拮抗剂阻断。鉴于轴突运输对神经元功能的根本重要性，这些观察结果可以解释在暴露于OP的人类中观察到的一些长期神经功能缺损。
The extensive use of organophosphates (OPs) is an ongoing environmental health concern due to multiple reports of OP-related neurologic abnormalities. The mechanism of the acute toxicity of OPs has been attributed to inhibition of acetylcholinesterase (AChE), but there is growing evidence that this may not account for all the long-term neurotoxic effects of OPs. In previous experiments (using ex vivo and in vitro model systems) we observed that the insecticide OP chlorpyrifos impaired the movements of vesicles and mitochondria in axons. Here, using a time-lapse imaging technique, we evaluated the OP-nerve agent diisopropylfluorophosphate (DFP) across a wide range of concentrations (subnanomolar to micromolar) for effects on fast axonal transport of membrane-bound organelles (MBOs) that contain the amyloid precursor protein (APP) tagged with the fluorescent marker Dendra2 (APPDendra2). Both 1 and 24 hours of exposure to DFP and a positive control compound, colchicine, resulted in a decrease in the velocity of anterograde and retrograde movements of MBOs and an increase in the number of stationary MBOs. These effects occurred at picomolar (100 pM) to low nanomolar (0.1 nM) concentrations that were not associated with compromised cell viability or cytoskeletal damage. Moreover, the effects of DFP on axonal transport occurred at concentrations that did not inhibit AChE activity, and they were not blocked by cholinergic receptor antagonists. Given the fundamental importance of axonal transport to neuronal function, these observations may explain some of the long-term neurologic deficits that have been observed in humans who have been exposed to OPs.