Unitat de Farmacologia i Farmacognòsia, Institut de Biomedicina (IBUB), Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Universitat de Barcelona, Nucli Universitari de Pedralbes, 08028 Barcelona, Spain.
Pharmacol Res. 2010 May;61(5):391-9. doi: 10.1016/j.phrs.2010.01.003. Epub 2010 Jan 18.
The toxicity caused by cell exposure to 1-methyl-4-phenylpyridinium ion (MPP(+)) is a useful model in the study of Parkinson's disease (PD). However, the exact molecular mechanisms triggered by MPP(+) in cell death are currently unclear. In the present research, we show that exposure to MPP(+) induce the cell death of neuroblastoma-derived dopaminergic B65 cells, which is not reversed by the widely known caspase inhibitor Z-VAD fmk or by calpain inhibition. Likewise, when B65 cells were treated with MPP(+), the DNA damage pathway that involves p53 was activated, and cells were arrested in the G(2)/M phase of the cell cycle. Interestingly, MPP(+) has two effects on the expression of cell cycle-related proteins. It increases the content of cyclins A, E, cdk2 and the phosphorylated form of pRb (serine 780). However, MPP(+) 5mM decreased the expression of cyclin D1, B1 and cdk4. The decrease in the expression of cyclin B1 may be related to the arrest of cells observed in the G(2)/M phase of cell cycle. The increase in S phase cell cycle proteins and retinoblastoma protein phosphorylation was an unexpected result. As the antioxidant trolox attenuated the process of cell loss and changes in the cell cycle, as measured by flow cytometry, we concluded that oxidative stress was involved in the effects of MPP(+) in this cell line. In summary, the present work characterizes the molecular changes involved in damage caused by MPP(+) in B65 cells, and highlights the effects of MPP(+) on molecules involved in the control of cell cycle progression.
细胞暴露于 1-甲基-4-苯基吡啶离子（MPP(+)) 所引起的毒性是研究帕金森病（PD）的有用模型。然而，目前尚不清楚 MPP(+) 在细胞死亡中引发的确切分子机制。在本研究中，我们表明，MPP(+) 诱导神经母细胞瘤衍生的多巴胺能 B65 细胞死亡，这不能被广泛使用的 caspase 抑制剂 Z-VAD fmk 或钙蛋白酶抑制所逆转。同样，当 B65 细胞用 MPP(+)处理时，涉及 p53 的 DNA 损伤途径被激活，细胞被阻滞在细胞周期的 G(2)/M 期。有趣的是，MPP(+) 对细胞周期相关蛋白的表达有两种作用。它增加了细胞周期蛋白 A、E、cdk2 和 pRb（丝氨酸 780）的磷酸化形式的含量。然而，MPP(+) 5mM 降低了细胞周期蛋白 D1、B1 和 cdk4 的表达。细胞周期蛋白 B1 的表达减少可能与细胞周期 G(2)/M 期观察到的细胞阻滞有关。S 期细胞周期蛋白和视网膜母细胞瘤蛋白磷酸化的增加是一个意外的结果。由于抗氧化剂 trolox 减弱了细胞丢失和细胞周期变化的过程，如流式细胞术所测量的，我们得出结论，氧化应激参与了 MPP(+) 在该细胞系中的作用。总之，本工作描述了 MPP(+) 在 B65 细胞中引起的损伤所涉及的分子变化，并强调了 MPP(+) 对细胞周期进程控制分子的影响。
