Imamura Keiko, Takeshima Takao, Nakaso Kazuhiro, Ito Satoru, Nakashima Kenji
Department of Neurology, Institute of Neurological Sciences, Tottori University, Faculty of Medicine, Yonago, Tottori, Japan.
Neurosci Lett. 2008 Aug 1;440(2):97-102. doi: 10.1016/j.neulet.2008.05.067. Epub 2008 May 23.
Pramipexole, a dopamine D2/D3 receptor agonist used in the treatment of Parkinson's disease, has been reported to have neuroprotective potential. We investigated the effect of pramipexole against cell death induced by a proteasome inhibitor, lactacystin, using primary mecencephalic neuronal cultures and SH-SY5Y cells. In E14 rat primary mesencephalic cultures, the number of surviving tyrosine hydroxylase (TH)-positive neurons and microtubule associated protein 2 (MAP2)-positive neurons was decreased by exposure to 1-5 microM lactacystin in a dose-dependent manner. Pretreatment with 100 microM pramipexole rescued TH-positive neurons and MAP2-positive neurons from the toxicity of lactacystin. The protective effect of pramipexole was not selective for TH-positive dopaminergic neurons. However, the treatment with 100 microM pramipexole did not protect SH-SY5Y cells against lactacystin-induced cell toxicity and proteasome dysfunction. We hypothesized that the protective effect of pramipexole against the lactacystin-toxicity was not direct but a secondary effect mediated by astrocytes. Therefore, we investigated the efficacy of conditioned medium collected from mecencephalic astrocytes treated with pramipexole. The conditioned medium increased the viability of SH-SY5Y cells against the toxicity of lactacystin. Pramipexole increased the levels of brain derived neurotrophic factor (BDNF) in the conditioned medium of astrocyte cultures. These protective effects were not significantly inhibited by dopamine D2 or D3 receptor antagonists. We demonstrated that pramipexole had the protective effect against lactacystin toxicity, mediated by a neurotrophic effect of astrocyte-produced factors including BDNF.
普拉克索是一种用于治疗帕金森病的多巴胺D2/D3受体激动剂，据报道具有神经保护潜力。我们使用原代中脑神经元培养物和SH-SY5Y细胞，研究了普拉克索对蛋白酶体抑制剂乳胞素诱导的细胞死亡的影响。在E14大鼠原代中脑培养物中，暴露于1-5微摩尔的乳胞素会以剂量依赖的方式减少存活的酪氨酸羟化酶（TH）阳性神经元和微管相关蛋白2（MAP2）阳性神经元的数量。用100微摩尔普拉克索预处理可使TH阳性神经元和MAP2阳性神经元免受乳胞素的毒性。普拉克索的保护作用对TH阳性多巴胺能神经元没有选择性。然而，用100微摩尔普拉克索处理并不能保护SH-SY5Y细胞免受乳胞素诱导的细胞毒性和蛋白酶体功能障碍。我们假设普拉克索对乳胞素毒性的保护作用不是直接的，而是由星形胶质细胞介导的次级效应。因此，我们研究了用普拉克索处理的中脑星形胶质细胞收集的条件培养基的功效。该条件培养基增加了SH-SY5Y细胞对乳胞素毒性的活力。普拉克索增加了星形胶质细胞培养物条件培养基中脑源性神经营养因子（BDNF）的水平。这些保护作用没有被多巴胺D2或D3受体拮抗剂显著抑制。我们证明普拉克索对乳胞素毒性具有保护作用，这是由包括BDNF在内的星形胶质细胞产生的因子的神经营养作用介导的。
