Understanding Susceptibility to Parkinson's Disease due to GBA1 Mutations

项目摘要 帕金森病（PD）是第二大最常见的神经退行性疾病，约有60，000名退伍军人 目前每年从VA医疗保健系统接受PD治疗。PD的特征是进行性 运动能力下降和认知障碍。尽管有巨大的医疗负担，我们对 PD的发病机制和治疗仍然有限。 葡萄糖苷酶β-酸1（GBA 1）基因突变是发生糖尿病的最强遗传风险因素。 特发性PD，与对照组相比，GBA 1突变携带者的风险增加约5倍。但大多数 携带GBA 1突变的个体不会发生PD，这表明其他遗传修饰剂会影响PD 易感性这些修饰物的鉴定将提供对PD发病机制的深入了解，并揭示 疾病修饰疗法的新靶点。拟议的工作重点是确定遗传修饰剂， 使用果蝇GBA 1缺陷模型的GBA 1介导的神经变性，使用这些修饰剂 了解导致PD的致病机制，并确定是否在 果蝇翻译成人类疾病的临床相关修饰物。 将使用GBA 1缺陷果蝇模型通过遗传筛选鉴定候选修饰物 我的目标（1）两个候选修饰剂，洗脑（bwa）和葡萄糖神经酰胺转移酶 1（GlcT-1）已经在前期工作中鉴定。这些修饰剂在神经酰胺中的作用 代谢表明，神经酰胺水平的降低可能是GBA 1介导的 神经变性我假设神经酰胺水平的降低损害了自噬体与 溶酶体，导致神经变性。我将通过识别脂质丰度的变化来检验这一假设 在具有bwa和GlcT-1过表达或功能丧失的GBA 1突变体和对照果蝇中， 从而对自噬通量和自噬体形态产生影响（目的2）。我还将测试是否增加 直接通过饮食补充的神经酰胺水平可以改善GBA 1突变表型， 包括受损的自噬这些研究将阐明脂质代谢和 GBA 1介导的发病机制中的病理性蛋白聚集，这仍然是难以捉摸的。在目标3中，我将 测试bwa和GlcT-1是否也是人类疾病的修饰剂，通过分析这些的人类同源物， 在GBA 1携带者的纵向队列中与症状进展速率相关的修饰符， 非携带者PD（目标3）。 拟议的工作使用了几种创新的方法，包括一种新的无脊椎动物模型GBA 1 缺乏表现出提示PD的表型，通过检测脂质代谢对自噬的作用， 遗传干扰和饮食补充，并试图翻译的结果，从果蝇 PD患者模型。这项工作将大大推进我们对PD发病机制的理解， 揭示了新的治疗靶点和新的脂质组学生物标志物。 我计划使用目标2和目标3中提出的方法来研究额外的 通过拟议的工作确定的改性剂。这将为新的发现提供令人兴奋的途径， 阐明负责PD的致病机制，并形成优异奖提案的基础， 在CDA 2期间提交。我的兴趣是脂质代谢改变导致神经退行性变， 从果蝇模型到PD患者队列的研究结果已经将我与我的研究区分开来。 导师，以及这些领域的额外培训将使我能够成功转型为独立人士 研究人员结合果蝇的机械实验工作与临床相关的发现在人类。

PROJECT SUMMARY Parkinson’s disease (PD) is the second most common neurodegenerative disease, and ~60,000 veterans currently receive care for PD from the VA Health Care System annually. PD is characterized by progressive motor decline and cognitive impairment. Despite significant medical burden, our understanding of the pathogenesis of PD and therapies remain limited. Mutations in the gene glucosidase, beta acid 1 (GBA1) are the strongest genetic risk factor for developing idiopathic PD, increasing risk by ~5-fold in GBA1 mutation carriers compared to controls. However, most individuals with GBA1 mutations do not develop PD, suggesting that additional genetic modifiers influence PD susceptibility. Identification of these modifiers would provide insight into the pathogenesis of PD, and reveal novel targets for disease-modifying therapies. The proposed work focuses on identifying genetic modifiers of GBA1-mediated neurodegeneration using a Drosophila GBA1 deficient model, using these modifiers to understand the pathogenic mechanisms causing PD, and determining whether modifiers identified in Drosophila translate to clinically relevant modifiers of human disease. Candidate modifiers will be identified through a genetic screen using a GBA1 deficient Drosophila model that I have developed (Aim 1). Two candidate modifiers, brainwashing (bwa) and glucosylceramide transferase 1 (GlcT-1) have already been identified in preliminary work. The function of these modifiers in ceramide metabolism suggests that decreased levels of ceramide may be responsible for GBA1-mediated neurodegeneration. I hypothesize that decreased ceramide levels impair fusion of autophagosomes to lysosomes, causing neurodegeneration. I will test this hypothesis by identifying alterations of lipid abundances in GBA1 mutant and control flies with overexpression or loss of function of bwa and GlcT-1, and examining resulting effects on autophagy flux and autophagosome morphology (Aim 2). I will also test whether increasing levels of ceramide directly through dietary supplementation can ameliorate GBA1 mutant phenotypes, including impaired autophagy. These studies will elucidate the mechanistic link between lipid metabolism and pathologic protein aggregation in GBA1-mediated pathogenesis, which has remained elusive. In Aim 3, I will test whether bwa and GlcT-1 are also modifiers of human disease, by analyzing human homologs of these modifiers for association with rate of progression of symptoms in a longitudinal cohort of GBA1 carriers and noncarriers with PD (Aim 3). The proposed work uses several innovative approaches, including a novel invertebrate model of GBA1 deficiency manifesting phenotypes suggestive of PD, testing the role of lipid metabolism on autophagy through genetic perturbations and dietary supplementation, and attempting to translate findings from a Drosophila model to PD patients. This work will significantly advance our understanding of PD pathogenesis, and could reveal novel therapeutic targets and new lipidomic biomarkers. I plan to use the proposed methodologies in Aims 2 and 3 to investigate the mechanisms of additional modifiers identified through the proposed work. This will provide exciting avenues for new discoveries, elucidate pathogenic mechanisms responsible for PD, and form the basis for a Merit Award proposal, to be submitted during the CDA2. My interests in lipid metabolism alterations contributing to neurodegeneration, and translation of findings from a Drosophila model to a cohort of PD patients already differentiate me from my mentors, and the additional training in these areas will allow me to successfully transition to an independent researcher combining mechanistic experimental work in Drosophila with clinically relevant findings in humans.