Mechanism and importance of innate immune activation in a Drosophila GBA mutant model of Parkinson's disease

帕金森病果蝇 GBA 突变模型中先天免疫激活的机制和重要性

• 批准号: 10039929
• 负责人: Leo J Pallanck
• 金额: $ 23.33万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-10 至 2022-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10039929
• 关键词: Address; Autophagocytosis; Brain; Ceramides; DIF factor; Data; Development; Disease; Disease model; Drosophila genus; Enzymes; Exhibits; Foundations; Gaucher Disease; Gene Expression; Genes; Genetic; Glucose; Glucosylceramides; Glycosphingolipids; Goals; Immune; Immune response; Immunologic Factors; Impairment; Infection; Inflammation; Inflammatory; Innate Immune Response; Innate Immune System; Lead; Lewy Body Dementia; Lipids; Locomotion; Longevity; Measures; Mediating; Medical; Membrane; Modeling; Molecular; Movement Disorders; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Orthologous Gene; Parkinson Disease; Pathogenesis; Pathogenicity; Pathway interactions; Pattern; Phenotype; Process; Production; Proteins; Proteomics; Publishing; RNA Interference; Reporting; Research Proposals; Risk Factors; Sphingolipids; Testing; Tissues; Transcript; Ubiquitin; Work; antimicrobial peptide; dietary manipulation; disease-causing mutation; experimental study; extracellular vesicles; fly; genetic association; genetic manipulation; glucosylceramidase; immune activation; immunogenic; innate immune pathways; knock-down; mutant; neuroinflammation; novel; pathogen; protein aggregation; protein degradation; therapy development; transcriptome sequencing; unpublished works; vesicular release

ABSTRACT: Mutations in the glucosylceramidase beta (GBA) gene cause the lysosomal lipid storage disorder Gaucher’s disease and are the most frequent genetic association with Parkinson’s disease and Lewy body dementia. GBA encodes glucocerebrosidase, a lysosomal enzyme that catalyzes the breakdown of the sphingolipid glucosylceramide to ceramide and glucose. To explore the mechanism by which mutations in GBA predispose to these diseases, we created a Drosophila model of glucocerebrosidase deficiency by inactivating the Drosophila GBA ortholog, Gba1b. Gba1b mutants recapitulate many of the features of these diseases, including shortened lifespan, locomotor impairment, accumulation of glucosylceramide, protein aggregation in brain and other tissues, and neurodegeneration. In recently published work, we reported the results of a proteomic study of Drosophila Gba1b mutants that revealed dramatic alterations in the abundance and turnover of extracellular vesicle (EV) proteins. Our experiments also demonstrated that these proteomic findings reflected actual changes in the composition of EVs, and that genetic perturbations targeting factors involved in the production of EVs suppressed a Gba1b mutant phenotype. In more recent unpublished work, we used RNA-Seq to compare transcript abundance in Gba1b mutants and controls. This study revealed a profound induction of the innate immune response pathway in Gba1b mutants. This induction was specific to Gba1b mutants and was further corroborated in our proteomic data, and RNAi-mediated knockdown of an innate immune pathway component partially suppressed the brain protein aggregation phenotype of Gba1b mutants. From these and other findings, we hypothesize that the production of glucosylceramide-enriched EVs by Gba1b mutants triggers an innate immune response because these EVs resemble the glucosylceramide-enriched EVs released by pathogens during infection. We further hypothesize that this innate immune response accounts for the phenotypes of Gba1b mutants. We propose two aims to address these hypotheses; the first will investigate the mechanism of immune activation, and the second will investigate the importance of immune activation to Gba1b mutant pathogenesis. Thus, the primary goal of our research proposal is to provide a foundation for further mechanistic work by asking the two most fundamental questions raised by our preliminary findings: how does innate immune activation occur in Gba1b mutants, and is it important to their phenotypes? Given the increasing evidence for neuroinflammation in neurodegenerative disorders, including those caused by GBA mutations, we anticipate that our work will have broad medical significance.

摘要： 葡萄糖神经酰胺酶β（GBA）基因突变导致溶酶体脂质储存障碍戈谢病 帕金森氏病和路易体痴呆是最常见的遗传关联。 GBA编码葡萄糖脑苷脂酶，一种催化鞘脂分解的溶酶体酶 葡糖神经酰胺转化为神经酰胺和葡萄糖。探讨GBA基因突变易患 针对这些疾病，我们建立了一个葡萄糖脑苷脂酶缺乏的果蝇模型， 果蝇GBA直系同源物，Gba 1b. Gba 1b突变体概括了这些疾病的许多特征， 包括寿命缩短、运动障碍、葡糖神经酰胺积累、蛋白质聚集 大脑和其他组织中，以及神经退化。在最近发表的工作中，我们报告了一个 对果蝇Gba 1b突变体的蛋白质组学研究显示， 细胞外囊泡（EV）蛋白的周转。我们的实验还表明，这些蛋白质组 研究结果反映了EV组成的实际变化，并且针对因子的遗传扰动 参与EV生产的基因抑制了Gba 1b突变表型。在最近未发表的研究中， 我们使用RNA-Seq比较Gba 1b突变体和对照中的转录本丰度。这项研究显示， Gba 1b突变体中先天免疫应答途径的深刻诱导。这种诱导是专门针对 Gba 1b突变体，并在我们的蛋白质组学数据中得到进一步证实，RNAi介导的Gba 1b基因敲低， 先天免疫途径组分部分抑制Gba 1b的脑蛋白聚集表型 变种人从这些和其他发现，我们假设，生产葡萄糖神经酰胺富集 Gba 1b突变体的EV触发先天免疫应答，因为这些EV类似于 在感染期间由病原体释放的富含葡糖神经酰胺的EV。我们进一步假设， 先天性免疫应答解释了Gba 1b突变体的表型。我们提出两个目标， 这些假设;第一个将研究免疫激活的机制，第二个将 探讨免疫激活对Gba 1b突变致病的重要性。因此， 我们的研究建议是通过询问两个最重要的问题，为进一步的机械工作提供基础。 我们的初步发现提出了一个基本问题：先天免疫激活是如何在Gba 1b中发生的？ 突变体，它对它们的表型重要吗？鉴于越来越多的证据表明， 神经退行性疾病，包括GBA突变引起的疾病，我们预计我们的工作将有 广泛的医学意义。