Metabolo-Genetic Dissection of GBA and Lysosomal Genes in Parkinson's Disease and Lewy Body Dementia

帕金森病和路易体痴呆中 GBA 和溶酶体基因的代谢遗传学解析

• 批准号: 10043151
• 负责人: Joshua M Shulman
• 金额: $ 24万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10043151
• 关键词: Adult; Affect; Aging; Alleles; Alzheimer' s disease related dementia; Animal Model; Animals; Autopsy; Biological Assay; Biological Markers; Brain; Cathepsins; Ceramides; Clinical; Data; Detection; Disease; Disease susceptibility; Dissection; Dose; Drosophila genus; Enhancers; Enzymes; Experimental Models; Foundations; Funding; Gaucher Disease; Genes; Genetic; Glucosylceramides; Heritability; Homo; Human; Human Genetics; Impairment; Individual; Lewy Bodies; Lewy Body Dementia; Lysosomes; Mass Spectrum Analysis; Mediating; Metabolism; Modification; NPC1 gene; Nerve Degeneration; Neurodegenerative Disorders; Neuronal Dysfunction; Odds Ratio; Parkinson Disease; Pathogenesis; Pathologic; Pathology; Pathway interactions; Penetrance; Phosphorylation; Protein Dynamics; Proteins; Risk; Series; Sphingolipids; Stress; Structure; Sum; Testing; Therapeutic; Transgenic Model; Transgenic Organisms; Validation; Variant; age related; aging brain; alpha synuclein; brain metabolism; clinically relevant; cohort; dementia risk; disorder risk; exome; fly; genetic manipulation; genetic risk factor; genetic variant; glucosylceramidase; in vivo; innovation; loss of function; neuron loss; neuropathology; neurotoxicity; protein aggregation; protein degradation; synucleinopathy

Synucleinopathies, including Lewy body dementia (LBD) and Parkinson’s disease (PD), are common and incurable neurodegenerative disorders with strong evidence for heritability. Loss-of-function variants in Glucocerebrosidase (GBA) cause Gaucher’s disease, a recessive lysosomal storage disorder (LSD). It is estimated that 85% or greater loss of Glucocerebrosidase activity is required to trigger Gaucher’s. Paradoxically however, heterozygous carriers of GBA variants—causing modest reductions in overall enzyme function—have a significantly increased risk of PD and LBD, and GBA alleles also dominantly modify risk of dementia among subjects with PD. Emerging evidence suggests that GBA loss of function may enhance the neurotoxicity of α-synuclein (αSyn), the pathological protein that aggregates to form brain Lewy bodies in PD and LBD. However, the mechanism by which partial reduction in GBA activity contributes to pathogenesis of synucleinopathy remains elusive. Since most GBA variant carriers do not develop disease in their lifetimes, other factors likely contribute to disease penetrance. In an exome-wide study, we discovered an aggregate genetic variant burden among 54 LSD genes associated with PD risk. In fact, over half of subjects carried at least one variant, and 21% carried 2 or more variants. These results suggest that (i) other LSD genes likely contribute to synucleinopathy, and (ii) LSD gene variants may interact with one another to modify risk and progression of neurodegeneration. In this proposal we test the hypothesis that partial, haploinsufficient loss of function in LSD genes disrupts sphingolipid metabolism, leading to enhanced lysosomal stress and increased vulnerability to αSyn-induced, age-dependent neurodegeneration. In compelling preliminary studies, we have performed comprehensive genetic manipulations of 94 conserved homologs of human LSD genes in a Drosophila transgenic model of αSyn-mediated neurodegeneration, identifying GBA and 17 other candidate enhancers. A preponderance of modifiers are implicated in lysosomal metabolism of ceramide and sphingolipids. Here, we will employ the powerful and rapid genetics available in Drosophila to systematically confirm interactions between LSD genes and αSyn-mediated neurodegeneration <Aim 1a> and assess impact on αSyn protein dynamics <Aim 1b>. To establish clinical relevance, LSD gene modifiers of αSyn will be examined for associations with PD/LBD pathology in human brain autopsy cohorts <Aim 1c>. In parallel, the most promising LSD gene modifiers of αSyn will be interrogated for impact on lysosomal structure and function <Aim 2a>, and we will perform mass-spectrometry to profile sphingolipid perturbations in a GBA allelic series with graduated reduction in Glucocerebrosidase activity <Aim 2b>. In sum, this exploratory project will establish a causal chain between partial loss-of-function in GBA and other LSD genes leading to subclinical derangements in lysosomal metabolism, αSyn neuropathology in the aging brain, neuronal dysfunction and death, and ultimately, the clinical manifestations of PD/LBD.

突触核蛋白病，包括路易体痴呆（LBD）和帕金森病（PD），是常见的， 无法治愈的神经退行性疾病，具有强有力的遗传性证据。功能丧失变体 葡萄糖脑苷脂酶（GBA）导致戈谢病，一种隐性溶酶体储存障碍（LSD）。是 据估计，需要85%或更多的葡糖脑苷脂酶活性损失才能触发戈谢病。 然而，奇怪的是，GBA变异的杂合子携带者-导致总体酶活性的适度降低， 功能-具有显著增加的PD和LBD的风险，并且GBA等位基因也主要改变PD和LBD的风险。 PD患者中的痴呆。新出现的证据表明，GBA功能的丧失可能会增强 α-突触核蛋白（αSyn）的神经毒性，在PD中聚集形成脑Lewy小体的病理蛋白 还有LBD。然而，GBA活性的部分降低有助于GBA发病机制的机制尚不清楚。 突触核蛋白病仍然难以捉摸。由于大多数GBA变异携带者在其一生中不会发生疾病， 其他因素也可能导致疾病复发。在一项外显子组范围的研究中，我们发现了一种聚集体， 与PD风险相关的54个LSD基因的遗传变异负担。事实上，超过一半的受试者在 至少一个变异，21%携带2个或更多变异。这些结果表明（i）其他LSD基因可能 有助于突触核蛋白病，和（ii）LSD基因变异可能相互作用，以修改风险， 神经变性的进展。在这个建议中，我们测试的假设，部分，单倍不足， LSD基因的功能丧失破坏了鞘脂代谢，导致溶酶体应激增强 以及对α-Syn诱导的年龄依赖性神经退行性变的易感性增加。地迫使 初步研究，我们已经进行了全面的遗传操作的94个保守的同源物， 人LSD基因在果蝇转基因模型中的α-Syn介导的神经变性，鉴定GBA 和其他17个候选增强子。大多数修饰剂参与溶酶体代谢， 神经酰胺和鞘脂。在这里，我们将利用果蝇强大而快速的遗传学， 系统地证实了LSD基因与α-Syn介导的神经退行性变之间的相互作用<Aim 1a>， 评估对αSyn蛋白动力学的影响<Aim 1b>。为了建立临床相关性，LSD基因修饰剂， 将在人脑尸检队列中检查αSyn与PD/LBD病理学的相关性<Aim 1c>。在 与此同时，最有前途的αSyn LSD基因修饰剂将被询问对溶酶体结构的影响 和功能<Aim 2a>，我们将进行质谱分析，以分析GBA中的鞘脂扰动 葡萄糖脑苷脂酶活性逐渐降低的等位基因系列<Aim 2b>。总之，这种探索性的 该项目将在GBA和其他LSD基因的部分功能丧失之间建立因果链， 溶酶体代谢的亚临床紊乱，老化脑中的αSyn神经病理学，神经元 功能障碍和死亡，以及最终的PD/LBD的临床表现。