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

作为翻译后修饰(PTM)的一种形式，靶蛋白的SUMO化已经被 然而，是否与帕金森氏病的病理有牵连仍有争议。 苏莫化有助于这种疾病，或者是一种保护机制(9)。我们最近出版的出版物 使用小鼠模型表明，相扑结合酶Ubc9的过度表达可以保护 已知的帕金森病诱发的纹状体和黑质细胞体中的多巴胺能轴突 导致帕金森症状的试剂(MPTP)(图1)(12)。此外，MPTP 治疗导致小鼠纹状体内α-突触核蛋白SUMO化减少(图2)，提示 MPTP诱导的毒性刺激去SUMO酶SENP从α-突触核蛋白中清除SUMOS，这可能与黑质中的多巴胺能神经元丢失有关。我们最近的结果 支持SENPs可以成为监管目标，以防止可能 是蛋白质聚集和神经元死亡途径的一部分。特别是，我们确定了 在n27细胞、小鼠模型和人类帕金森病患者SNPC中一致认为 在已知的6-7个哺乳动物SENPs中，SENP1被MPP+或 α-突触核蛋白介导的毒性的预形成纤维(PFF)(图3，4)。然而，MPTP诱导了 毒性不能概括典型的蛋白质聚集介导的帕金森病病理。因此， 我们采用最近建立的利用α-突触核蛋白的预形成纤维(Pff)的方法 模拟蛋白质聚集介导的帕金森病病理。我们检验了阻止的假设 脱硫酶，SENP1，防止PFF介导的多巴胺能神经元毒性。 使用SENP1 RNAi、显性负性或化学抑制剂，我们将评估靶标验证 抑制SENP1，以提高蛋白质的稳定性/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SN中的SENP1表达 额外的人类帕金森病中脑显著高于年龄和性别匹配的人 健康对照组，每组增加10个样本。同时，我们将评估蛋白质组学 用质谱仪研究注射PFF的小鼠脑内SUMO化和SENPs的变化。这 这项研究将为保护多巴胺能神经元免受蛋白质聚集介导的导致帕金森病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，以及提供巨大的机会 在HBCU学习基本科学技术的研究生人数不足 以及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.