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基因中的突变是帕金森氏病（PD）的已知危险因素中最常见的。尽管临床研究认为GBA1突变与PD发展之间的联系有很强的案例，但缺乏机械见解。 GBA1编码葡萄糖脑苷酶（GCASE），一种溶酶体酶，将葡萄糖基酰胺（Glucer）水解为葡萄糖和神经酰胺，并且缺乏Gaucher病（GD）。最近的研究表明，GCASE与PD相关的淀粉样蛋白α-核蛋白（alpha-syn）之间的关系。但是，负责关联的特定分子机制仍然难以捉摸。 在我们的工作中，我们专注于溶酶体中α-Syn和Gcase相互作用的结构功能关系。我们已经评估了酶促活性，通过中子反射测定法表征了膜结合的蛋白质复合物，并评估了saposin c（GCASE激活剂）对复杂形成和GCASE活性的影响。在定义驱动GCASE与alpha-syn水平之间相互关系的分子相互作用时，我们转向研究溶酶体中α-Syn的降解方式。 随着溶酶体去除易于聚集的物种或α-syn的过量水平，溶酶体内发生的分子相互作用（例如与GCASE）是相关的。 这种相互作用可以通过改变α-Syn裂解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。 我们正在检验有关在健康和疾病相关的疾病下溶酶体如何对α-syn蛋白抑制作用的假设。 具体而言，我们正在研究α-Syn和溶酶体酶，半胱氨酸组织蛋白酶和GCASE之间的关系。 我们的工作表明半胱氨酸组织蛋白酶在α-Syn的溶酶体清除率中的直接作用。 我们对如何将这些酶定为PD进展中的干预策略感兴趣。 使用半胱氨酸的组织蛋白酶，我们的数据对于降解α-syn原纤维降解的潜力尤其令人信服。 对于GCASE，其水平或活性的增强似乎可以改善基于细胞和动物PD模型中的α-Syn毒性。但是，为什么发生这种情况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α-Syn细胞清除率的可行治疗剂，并阐明负责PD和GCASE浓度风险之间相关性的机制。