Studies of molecular mechanisms of rotenone-induced apoptosis and neurotrophic substances for dopaminergic neurons

鱼藤酮和锰都可能是多种细胞和神经元类型的神经毒素，包括多巴胺能神经元，并诱导各种细胞的凋亡。本文主要研究鱼藤酮的毒性机制。鱼藤酮通过增加线粒体活性氧的产生而诱导PC 12细胞凋亡，但对JNK和p38 MAPK通路的激活作用不大。神经生长因子抑制鱼藤酮诱导的细胞凋亡是通过激活PI 3激酶途径而不是MAP激酶途径实现的。神经突生长促进素（Neurite outgrowth-promoting erglandins，NEPPs）是一种环戊烯酮前列腺素衍生物，包括NEPP 6和NEPP 11，具有神经营养作用。它们在神经生长因子存在下促进PC 12细胞和背根神经节外植体的神经突生长，并防止由各种刺激诱导的HT 22细胞和皮质神经元的神经元细胞死亡。然而，这些在相对高的浓度下也是有毒的。在这项研究中， 关于我们 用caspase-3/7活性测定法筛选化学合成的NEPP衍生物。44种衍生物中的几种化合物（GIF-0642、GIF-0643、GIFU-0644、GIF-0745、GIF-0747）抑制锰诱导的PC 12细胞中caspase-3/7的活化。此外，Western印迹显示GIF-0642和GIF-0747抑制锰诱导的caspase-9活化。GIF-0642和GIF-0747也完全抑制锰诱导的PC 12细胞DNA断裂。这些结果表明，化合物防止锰诱导的细胞凋亡。此外，NEPP衍生物抑制谷氨酸诱导的半胱天冬酶-3/7激活在HT 22海马细胞系。有效的NEPP衍生物具有苯硫基作为常见结构。结果表明，苯硫基在NEPP衍生物的抗凋亡作用中起重要作用。进一步努力修饰环戊烯酮前列腺素衍生物的结构，以增强对神经毒素诱导的细胞凋亡的抑制作用并消除细胞毒性，可以提供有助于预防神经退行性疾病如帕金森病的神经营养小分子。少

Both rotenone and manganese are possible neurotoxins for a wide variety of cell and neuronal types including dopaminergic neurons and induce apoptosis in various cells. In this study, we focused on the mechanism of rotenone as toxins. Rotenone induced apoptosis via enhancing the amount of mitochondrial ROS production whereas it has little effect on the activation of JNK and p38 MAPK pathways in PC12 cells. Nerve growth factor suppressed rotenone-induced apoptosis through the activation of the PI 3-kinase pathway not MAP kinase pathway. Neurite outgrowth-promoting prostaglandins (NEPPs), cyclopentenone prostaglandin derivatives including NEPP6 and NEPP11, are found to be neurotrophic. They promote neurite outgrowth of PC12 cells and dorsal root ganglia explants in the presence of nerve growth factor, and prevent neuronal cell death of HT22 cells and cortical neurons induced by various stimuli. However, these are also toxic at relatively high concentrations. In this study, a highly sensi … More tive assay of caspase-3/7 was used for screening chemically synthesized NEPP derivatives. Several compounds (GIF-0642, GIF-0643, GIFU-0644, GIF-0745, GIF-0747) out of 44 derivatives inhibited manganese-induced activation of caspase-3/7 in PC12 cells. In addition, Western blotting showed that GIF-0642 and GIF-0747 inhibited manganese-induced caspase-9 activation. GIF-0642 and GIF-0747 also completely inhibited manganese-induced DNA fragmentation in PC12 cells. These results suggest that the compounds prevent manganese-induced apoptosis. Furthermore, NEPP derivatives suppressed glutamate-induced caspase-3/7 activation in HT22 hippocampal cell line. Effective NEPP derivatives have phenylsulfanyl group as a common structure. The results indicate that the phenylsulfanyl group plays an important role in anti-apoptotic effect of NEPP derivatives. Further efforts to modify the structure of cyclopentenone prostaglandin derivatives that strengthen the inhibitory action on neurotoxin-induced apoptosis and eliminate cytotoxicity may provide neurotrophic small molecules that are helpful in preventing neurodegenerative disorders such as Parkinson's disease. Less