Defining a Molecular Link between Parkinson and Gaucher Diseases

定义帕金森病和戈谢病之间的分子联系

• 批准号: 10008811
• 负责人: Jennifer Lee
• 金额: $ 31.71万
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10008811
• 关键词: Address; Amyloid; Animals; Binding; Binding Proteins; Biochemical; Cathepsin L; Cathepsins; Cell model; Cells; Ceramides; Clinical Research; Complex; Cysteine; Data; Development; Disease; Disease Progression; Disease model; Enzymes; Gaucher Disease; Genes; Glucose; Glucosylceramides; Intervention; Lewy Bodies; Link; Lipids; Lysosomes; Membrane; Molecular; Molecular Conformation; Mutation; Neutrons; Parkinson Disease; Patients; Peptide Hydrolases; Proteins; Proteolysis; Research; Risk; Risk Factors; Role; Site; Specificity; Structure-Activity Relationship; Testing; Therapeutic Agents; Toxic effect; Work; alpha synuclein; base; beta-Glucosidase Stimulating Protein; biophysical analysis; glucosylceramidase; in vivo; insight; interest; novel therapeutic intervention; protein complex; proteostasis

Mutations in the GBA1 gene are the most common of the known risk factors for Parkinson disease (PD). While clinical studies argue a strong case towards a link between GBA1 mutations and the development of PD, mechanistic insights have been lacking. GBA1 encodes glucocerebrosidase (GCase), a lysosomal enzyme which hydrolyzes glucosylceramide (GluCer) into glucose and ceramide and is deficient in Gaucher disease (GD). Recent research suggests a relationship between GCase and the PD-related amyloid-forming protein, alpha-synuclein (alpha-syn); however, the specific molecular mechanisms responsible for association remain elusive. In our work, we focused on the structure-function relationship of alpha-syn and GCase interaction in the lysosome. We have evaluated enzymatic activity, characterized the membrane-bound protein complex by neutron reflectometry, and assessed the effect of Saposin C, an activator for GCase, on complex formation and GCase activity. In defining the molecular interactions that drive the reciprocal relationship between GCase and alpha-syn levels in vivo, we have turned to investigate how alpha-syn is degraded in the lysosome. As the lysosome removes aggregation-prone species or excess levels of alpha-syn, molecular interactions that occur within the lysosome such as with GCase would be pertinent. Such interactions could modulate proteolysis efficiency by altering availability of alpha-syn cleavage sites and dictate protease specificity and efficacy. We are testing hypotheses on how lysosomes contribute to alpha-syn proteostasis under healthy and disease-related conditions. Specifically, we are investigating the relationship between alpha-syn and lysosomal enzymes, cysteine cathepsins and GCase. Our work points to a direct role of cysteine cathepsins in the lysosomal clearance of alpha-syn. We are interested in how these enzymes could be targeted as an intervention strategy in PD progression. With cysteine cathepsins, our data are especially compelling for the potential for cathepsin L (CtsL) to degrade alpha-syn fibrils. For GCase, the enhancement of its levels or activity appears to ameliorate alpha-syn toxicity in cell-based and animal PD models; however, the molecular basis for why this occurs is not well understood. Our research efforts are addressing both these fronts: to evaluate whether CtsL could be a viable therapeutic agent towards cellular clearance of alpha-syn and to elucidate the mechanism(s) responsible for the observed correlation between risk for PD and GCase concentration.

GBA1 基因突变是帕金森病 (PD) 已知危险因素中最常见的。尽管临床研究有力证明 GBA1 突变与 PD 发展之间存在联系，但仍缺乏机制见解。 GBA1 编码葡萄糖脑苷脂酶 (GCase)，这是一种溶酶体酶，可将葡萄糖神经酰胺 (GluCer) 水解为葡萄糖和神经酰胺，并且在戈谢病 (GD) 中缺乏。最近的研究表明 GCase 与 PD 相关的淀粉样蛋白形成蛋白 α-突触核蛋白 (alpha-syn) 之间存在关系；然而，负责关联的具体分子机制仍然难以捉摸。 在我们的工作中，我们重点研究溶酶体中 α-syn 和 GCase 相互作用的结构-功能关系。我们评估了酶活性，通过中子反射测定法表征了膜结合蛋白复合物，并评估了 GCase 激活剂 Saposin C 对复合物形成和 GCase 活性的影响。在定义驱动体内 GCase 和 α-syn 水平之间相互关系的分子相互作用时，我们转而研究 α-syn 在溶酶体中如何降解。 当溶酶体去除易于聚集的物质或过量的 α-syn 时，溶酶体内发生的分子相互作用（例如与 GCase 的相互作用）将是相关的。 这种相互作用可以通过改变α-syn切割位点的可用性来调节蛋白水解效率，并决定蛋白酶的特异性和功效。 我们正在测试关于溶酶体如何在健康和疾病相关条件下促进 α-syn 蛋白质稳态的假设。 具体来说，我们正在研究 α-syn 与溶酶体酶、半胱氨酸组织蛋白酶和 GCase 之间的关系。 我们的工作指出半胱氨酸组织蛋白酶在溶酶体清除α-syn 中的直接作用。 我们感兴趣的是如何将这些酶作为 PD 进展的干预策略。 对于半胱氨酸组织蛋白酶，我们的数据特别引人注目，因为组织蛋白酶 L (CtsL) 具有降解 α-syn 原纤维的潜力。 对于 GCase，其水平或活性的增强似乎可以改善细胞和动物 PD 模型中的 α-syn 毒性；然而，这种现象发生的分子基础尚不清楚。 我们的研究工作正在解决这两个方面：评估 CtsL 是否可以成为细胞清除 α-syn 的可行治疗剂，并阐明导致 PD 风险和 GCase 浓度之间观察到的相关性的机制。