Functional assessment of pathological α-syn and Aβ species in LBD

LBD 中病理 α-syn 和 Aβ 物种的功能评估

• 批准号: 10237303
• 负责人: Pamela J McLean
• 金额: $ 57.56万
• 依托单位: MAYO CLINIC JACKSONVILLE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-20 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10237303
• 关键词: Alleles; Alzheimer' s Disease; Amyloid beta-Protein; Autophagocytosis; Autopsy; Biochemical; Biological; Biological Assay; Brain; Brain region; Cell model; Cells; Characteristics; Clinical; Cognitive deficits; Collaborations; Complement; Complex; Dementia; Dementia with Lewy Bodies; Development; Diagnostic; Disease; Enzymes; Genetic; Genetic Risk; Genetic Variation; Health; Human; Immunoassay; Impairment; Individual; Induced pluripotent stem cell derived neurons; Knowledge; Lewy Bodies; Lewy Body Dementia; Lipids; Lysosomes; Measures; Membrane; Methods; Microscopy; Molecular Conformation; Mutation; Neurons; Parkinson Disease; Parkinson' s Dementia; Pathologic; Pathway interactions; Patients; Positioning Attribute; Process; Proteins; Proteomics; Reporter; Research Personnel; Resolution; Scanning; Seeds; Senile Plaques; Slide; Structure; Subcellular Fractions; System; Tissues; Toxic effect; Validation; alpha synuclein; arm; beta pleated sheet; brain tissue; dementia risk; genetic risk factor; glucosylceramidase; in vivo; lipidomics; motor deficit; motor symptom; neuropathology; neurotoxic; novel; prion-like; protein structure; response; single molecule; transcriptomics

ABSTRACT Elucidation of underlying disease mechanisms in Lewy body dementia requires the systematic characterization of disease-specific changes in LBD brain tissue. The combination of dementia and motor symptoms at the clinical level is reflected in the neuropathology by the accumulation of alpha-synuclein (α-syn) in Lewy bodies and beta-amyloid (Aβ) in amyloid plaques. Both Aβ and α-syn are capable of aggregating into oligomers, fibrils, and beta sheets, but the aggregates that form are extremely heterogeneous in terms of both structure and function. The identification of which specific subspecies of the proteins are neurotoxic or support aggregation is poorly understood and as a result development of diagnostics and treatments that depend on knowledge of protein structure has been slow. Recent studies have suggested a ”seeded” or “prion-like” propagation for both α-syn and Aβ, indicating that abnormal conformations may ‘spread’ from diseased to healthy cells. While synthetic seeds of α-syn and Aβ confer toxicity in cells through various mechanisms, it is well known that the exact method of preparing these species influences their bioactivity to a high degree. Herein we take the next important step to analyze the actual subspecies from post-mortem brains, to define and compare aggregates, and identify mechanisms of toxicity and spreading underlying the selective regional vulnerabilities. We will extract soluble and insoluble α-syn and Aβ species from neuropathologically confirmed LBD brains with or without genetic LBD risk factors for structural and functional characterization. We will assess load and distribution of α-syn and Aβ subspecies and will detail their characteristics including size, structure and self- templating capabilities (Aim 1). The critical involvement of autophagy-lysosomal pathways in LBD is emphasized by the underlying genetic risks for LBD. Besides mutations in glucocerebrosidase (GBA) that interfere with lysosomal functions, it is well established that individuals with the APOE ϵ4 allele have a 6-fold greater risk for DLB. We will assess alterations in lysosome function in LBD brain and determine their response and contribution to processing, aggregation, and toxicity of α-syn and Aβ subspecies (Aim 2). We will use patients’ iPSC-derived neurons with different genetic risk factors to functionally validate the contribution to aggregation, toxicity and spreading of α-syn and Aβ (Aim 3). The expertise of this group of investigators synergizes to identify differences in structure and function of subspecies, to investigate mechanisms of aggregation and toxicity, and to unravel the contributions of the genetic variations and alterations in selective autophagy pathways to regional vulnerabilities. This puts us in a unique position to complement the studies of Projects 1, 2, and 3 of this CWOW at multiple levels and towards the full characterization of α-syn and Aβ subspecies.

抽象的 阐明路易体痴呆的潜在疾病机制需要系统表征 LBD 脑组织的疾病特异性变化。痴呆症和运动症状的结合 临床水平通过路易体中α-突触核蛋白（α-syn）的积累反映在神经病理学中 和淀粉样斑块中的β-淀粉样蛋白(Aβ)。 Aβ 和 α-syn 都能够聚集成寡聚物、原纤维、 和β片层，但形成的聚集体在结构和 功能。确定哪些特定的蛋白质亚种具有神经毒性或支持聚集 人们对这些知识知之甚少，因此诊断和治疗的发展依赖于知识 蛋白质结构进展缓慢。最近的研究表明，两者都具有“种子”或“朊病毒样”传播 α-syn 和 Aβ，表明异常构象可能从患病细胞“传播”到健康细胞。尽管 α-syn 和 Aβ 的合成种子通过各种机制赋予细胞毒性，众所周知， 制备这些物种的精确方法在很大程度上影响它们的生物活性。这里我们采取下一个 分析死后大脑的实际亚种、定义和比较聚合体的重要一步， 并确定选择性区域脆弱性背后的毒性和传播机制。我们将 从神经病理学证实的 LBD 大脑中提取可溶性和不溶性 α-syn 和 Aβ 物种，或者 没有用于结构和功能表征的遗传 LBD 危险因素。我们将评估负载并 α-syn 和 Aβ 亚种的分布，并将详细说明它们的特征，包括大小、结构和自 模板功能（目标 1）。自噬-溶酶体途径在 LBD 中的关键参与是 LBD 的潜在遗传风险强调了这一点。除了葡萄糖脑苷脂酶（GBA）突变之外 干扰溶酶体功能，众所周知，携带 APOE ϵ4 等位基因的个体具有 6 倍的 DLB 的风险更大。我们将评估 LBD 大脑中溶酶体功能的变化并确定它们的反应 以及对 α-syn 和 Aβ 亚种的加工、聚集和毒性的贡献（目标 2）。我们将使用 患者的 iPSC 衍生神经元具有不同的遗传风险因素，以在功能上验证其贡献 α-syn 和 Aβ 的聚集、毒性和扩散（目标 3）。该研究小组的专业知识 协同作用，识别亚种结构和功能的差异，研究机制 聚集和毒性，并揭示遗传变异和选择性改变的贡献 自噬途径导致区域脆弱性。这使我们处于独特的地位来补充以下研究： 本 CWOW 的项目 1、2 和 3 在多个层面上实现 α-syn 和 Aβ 的全面表征 亚种。