Prevention of alpha-synuclein deSUMOylation as a Parkinson's therapeutic target

翻译后修饰（PTM）的一种形式，靶蛋白的SUMO化已经被发现。 与帕金森病病理学有关（10），然而，关于是否 SUMO化有助于疾病或保护机制（9）。我们最近的出版物 使用小鼠模型表明，SUMO缀合酶Ubc9的过表达可以保护 纹状体中的多巴胺能轴突尖端和SN中的细胞体来自已知的PD诱导的神经元凋亡。 试剂（MPTP）导致帕金森症状（图1）（12）。此外，MPTP 治疗导致小鼠纹状体中α-突触核蛋白的SUMO化降低（图2），表明 MPTP诱导的毒性刺激deSUMO酶，SENP从α-突触核蛋白中去除SUMO，这可能与SN中的多巴胺能神经元丢失相关。我们最近的成果 支持SENP可以是调节靶点，以防止去SUMO化过程， 是蛋白质聚集和神经元死亡途径的一部分。特别是，我们发现， 在N27细胞、小鼠模型和人类帕金森病患者SNpc中一致， 在已知的6 - 7种哺乳动物SENP中，SENP 1被MPP+或 预先形成的纤维（PFF）的α-突触核蛋白介导的毒性（图3、4）。然而，MPTP诱导 毒性不能概括典型的蛋白质聚集介导的PD病理学。因此，我们认为， 我们采用最近建立的方法，使用α-突触核蛋白的预成纤维（PFF）， 模拟蛋白质聚集介导的PD病理。我们检验了一个假设， 去SUMO化酶SENP 1防止PFF介导的多巴胺能神经元毒性。 使用SENP1 RNAi、显性阴性或化学抑制剂，我们将评估靶标验证 抑制SENP 1以增强蛋白质稳定性/溶解性并防止PFF诱导的蛋白质错误折叠和聚集。此外，我们还将验证SENP1在SN中的表达， 额外的人PD中脑的水平显著高于年龄和性别匹配的人PD中脑的水平。 使用每组另外10个样品的健康对照。同时，我们将评估蛋白质组学 使用质谱法测定注射PFF的小鼠脑中SUMO化和SENP的变化。这 这项研究将为保护多巴胺能神经元免受导致帕金森病的蛋白质聚集介导的毒性提供新的策略。我们的潜在结果将导致有意义的 出版物和揭示新的目标验证，以及提供了很大的机会， 在HBCU学习基本科学技术的研究生人数不足（不足） 和领先科学团体的独特方法。

A form of post-translational modifications (PTM), SUMOylation of target proteins has been implicated in Parkinson’s disease pathology (10), however, it is still debatable as to whether SUMOylation contributes to the disease or is a protective mechanism (9). Our recent publication using mouse models suggest that the overexpression of SUMO conjugase, Ubc9 protects dopaminergic axon tips in the striatum and cell bodies in the SN from the known PD-inducing reagent (MPTP) that results in Parkinsonian symptoms (Fig 1) (12). In addition, the MPTP treatment results in decreased SUMOylation of α-synuclein in mouse striatum (Fig 2), suggesting that MPTP-induced toxicity stimulates the deSUMO enzyme, SENP for removing SUMOs from α-synuclein, which may be associated with dopaminergic neuronal loss in the SN. Our recent results support that SENPs can be regulatory targets to prevent the deSUMOylation process that may be a part of protein aggregation and neuronal death pathway. Particularly, we identified consistently in N27 cells, mouse models and human Parkinson’s disease patients SNpc that SENP1 among known 6-7 mammalian SENPs, was significantly upregulated by MPP+ or the preformed fibrils (PFF) of α-synuclein-mediated toxicity (Figs 3,4). However, the MPTP induced toxicity does not recapitulate the typical protein aggregation-mediated PD pathology. Therefore, we adopt the recently established method using the preformed fibril (PFF) of α-synuclein for mimicking protein aggregation-mediated PD pathology. We test the hypothesis that blocking deSUMOylating enzyme, SENP1 prevents PFF-mediated toxicity in dopaminergic neurons. Using SENP1 RNAi, dominant negative, or chemical inhibitors, we will assess the target validation of SENP1 inhibition to enhance protein stability/solubility and to prevent PFF-induced protein mis-folding and aggregation. In addition, we will also verify that SENP1 expression in the SN from additional human PD midbrains was significantly higher than that in age- and gender-matched healthy controls using additional 10 samples per group. In parallel, we will assess the proteomics shifts in SUMOylation and SENPs in PFF-injected mouse brains using mass spectrometry. This study will provide new strategies for protecting dopaminergic neurons from protein aggregation-mediated toxicity that leads to Parkinson’s disease. Our potential outcome will result in meaningful publications and reveal novel target validation, as well as offering great opportunities for underrepresented (under)graduate students at an HBCU to learn essential scientific techniques and unique approaches from leading scientific groups.