Sabolek Michael, Mieskes Ines, Lenk Thomas, Lehmensiek Vera, Hermann Andreas, Schwarz Johannes, Storch Alexander
Department of Neurology, University of Ulm, Ulm, Germany.
Neurotoxicology. 2008 Jul;29(4):714-21. doi: 10.1016/j.neuro.2008.04.007. Epub 2008 Apr 25.
Although extensive knowledge exists on selective vulnerability of dopaminergic neurons against parkinsonism-inducing neurotoxins, there is a complete lack of such data on immature neuroprogenitors. Here we investigated the toxicity of 1-methyl-4-phenylpyridinium (MPP+), 6-hydroxydopamine (6-OHDA) and the free radical generator H2O2 on various developmental stages of predopaminergic mesencephalic neuroprogenitors (mNPCs) to evaluate stage-dependency of selective dopaminergic neurotoxicity. Striatal NPCs (sNPCs) without dopaminergic differentiation potential served as controls. Exposure of both undifferentiated NPCs to MPP+ resulted in concentration-dependent cell death at concentrations of >10 microM after 72 h without differences between both cell types, while 6-OHDA led to relevant cell death at 1000 microM after 24h with significant higher sensitivity of mNPCs compared to sNPCs. H2O2 did not induce relevant cell death in all cell types. In NPC cultures differentiated for 14 days, MPP+ showed enhanced toxicity compared to the undifferentiated counterparts, but no significant differences between both NPC type and differentiation conditions. 6-OHDA showed similar toxicity pattern in differentiated compared to undifferentiated NPCs. By evaluating the toxicity of MPP+ on MAP2ab+ neurons derived from both mNPCs and sNPCs as well as tyrosine hydroxylase (TH)+ dopaminergic cells from mNPCs, we found concentration-dependent cell death of all cell types with no increased vulnerability of TH+ cells. Primary TH+ neurons showed significantly higher vulnerability to MPP+. Together, we demonstrated stage-dependent vulnerability of NPCs towards dopaminergic neurotoxins, but no selective vulnerability of NPC-derived TH+ dopaminergic cells towards MPP+. This cell system seems not suitable as a screening tool for selective dopaminergic toxicity.
尽管对于多巴胺能神经元对诱发帕金森病的神经毒素的选择性易损性已有广泛了解，但关于未成熟神经祖细胞的此类数据却完全缺失。在此，我们研究了1-甲基-4-苯基吡啶离子（MPP+）、6-羟基多巴胺（6-OHDA）和自由基生成剂H2O2对多巴胺能中脑前体细胞（mNPCs）不同发育阶段的毒性，以评估选择性多巴胺能神经毒性的阶段依赖性。无多巴胺能分化潜能的纹状体NPCs（sNPCs）作为对照。未分化的两种NPCs暴露于MPP+后，72小时后浓度>10 microM时会导致浓度依赖性细胞死亡，两种细胞类型之间无差异，而6-OHDA在24小时后1000 microM时会导致相关细胞死亡，与sNPCs相比，mNPCs的敏感性显著更高。H2O2在所有细胞类型中均未诱导相关细胞死亡。在分化14天的NPC培养物中，与未分化的对应物相比，MPP+显示出增强的毒性，但两种NPC类型和分化条件之间无显著差异。与未分化的NPCs相比，6-OHDA在分化的NPCs中显示出相似的毒性模式。通过评估MPP+对源自mNPCs和sNPCs的MAP2ab+神经元以及源自mNPCs的酪氨酸羟化酶（TH）+多巴胺能细胞的毒性，我们发现所有细胞类型均存在浓度依赖性细胞死亡，TH+细胞并无增加的易损性。原代TH+神经元对MPP+的敏感性显著更高。总之，我们证明了NPCs对多巴胺能神经毒素存在阶段依赖性易损性，但NPC衍生的TH+多巴胺能细胞对MPP+并无选择性易损性。该细胞系统似乎不适合作为选择性多巴胺能毒性的筛选工具。
