Exploring the Pathogenic Mechanisms of Batten's disease MFSD8 mutations using patient iPSC derived neurons.

使用患者 iPSC 衍生的神经元探索巴顿病 MFSD8 突变的致病机制。

• 批准号: 10467764
• 负责人: Joseph R Mazzulli
• 金额: $ 24万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10467764
• 关键词: Adolescent; Amino Acids; Astrocytes; Axon; Biochemical; Biological Assay; Biological Markers; Blindness; Blood; Brain; CTSD gene; Categories; Cathepsins B; Cell Death; Cell Line; Cells; Ceroid; Cessation of life; Childhood; Coculture Techniques; Data; Dementia; Dendrites; Disease; Disease Progression; Event; Fibroblasts; Foundations; Frontotemporal Dementia; Functional disorder; Genes; Genetic; Genetic Diseases; Heterozygote; Histopathology; Hydrolase; In Vitro; Induced pluripotent stem cell derived neurons; Inherited; Lead; Lewy Body Dementia; Link; Lysosomal Storage Diseases; Lysosomes; Maintenance; Mass Spectrum Analysis; Membrane Proteins; Modeling; Mutation; Nerve Degeneration; Neurites; Neurodegenerative Disorders; Neuroglia; Neurologic Dysfunctions; Neurologic Symptoms; Neuronal Ceroid-Lipofuscinosis; Neurons; PARK9 gene; Parkinson Disease; Pathogenicity; Pathology; Pathway interactions; Patients; Pharmacology; Phenotype; Point Mutation; Population; Proteins; Proteome; Proteomics; Role; Seizures; Solubility; Spielmeyer-Vogt Disease; Stable Isotope Labeling; Structure; Techniques; Toxic effect; Toxin; Variant; Western Blotting; Work; age related; age related neurodegeneration; alpha synuclein; extracellular; falls; glucosylceramidase; induced pluripotent stem cell; infancy; inhibitor; insight; link protein; lipopigments; loss of function; loss of function mutation; neuronal survival; neurotoxicity; new therapeutic target; novel; novel therapeutics; personalized medicine; premature; presynaptic; protein aggregation; proteostasis; solute; synucleinopathy

Mutations in the MFSD8 gene cause CLN7 Batten’s disease (BD), a rare neurodegenerative lysosomal storage disorder characterized by the accumulation of a lipopigment called ceroid in the brain. Furthermore, MFSD8 mutations were recently associated with frontotemporal dementia (FTD), and other BD-associated genes are linked to Parkinson’s disease (ATP13A2) and other subtypes of FTD (GRN, CTSD). CLN7 BD falls within a broader category of pediatric diseases called neuronal ceroid lipofuscinoses (NCL) that share common histopathology of ceroid accumulation in neurons and neurological symptoms including dementia, blindness, seizures, and premature death. The MFSD8 gene encodes the CLN7 protein, a membrane protein of unknown function that is localized to lysosomes. Mutations that cause CLN7 BD are loss of function and many of the known mutations result in premature stops or point mutations that destabilize the protein. Our previous studies in patient fibroblasts demonstrated that loss of CLN7 reduces lysosomal hydrolase activity, autophagic flux, and the accumulation of autofluorescent material. While these studies contributed to our understanding of how CLN7 leads to disease, the mechanisms that lead to neurodegeneration are not known. Furthermore, there are no studies done in relevant patient-derived neuronal models. Here, we propose to explore the mechanisms of neurotoxicity caused by CLN7 mutations, using a several iPSC-lines derived from distinct BD patients. Our preliminary data indicates that CLN7 BD lines can develop into cortical neurons in vitro, but demonstrate lysosomal phenotypes and reduced neurite extensions. In aim 1, we plan to use this established neuronal model to determine how loss of CLN7 influences the stability of the proteome and protein solubility to discover novel pathways and generate hypotheses for how cell death occurs in CLN7 BD. In aim 2, we will assess rescue mechanisms that aim to restore protein homeostasis in CLN7 neurons, as well as co-culturing wild-type astrocytes with CLN7-BD neurons to assess the role of glia cells in dementia. Since almost no mechanistic information is known about how CLN7 causes neurological dysfunction, our studies have the potential to uncover novel therapeutic pathways for CLN7 BD and other NCLs that share similar pathologies. Beyond NCLs, mutations in MFSD8 are associated with FTD, an age-related neurodegenerative disorder, and therefore our studies may be relevant to more common age-related neurodegeneration. Since there is accumulating evidence for lysosomal dysfunction common sporadic diseases including Parkinson’s disease and other synucleinopathies, our studies may have a broad impact on the field.

MFSD8 基因突变会导致 CLN7 巴顿氏病 (BD)，这是一种罕见的神经退行性溶酶体贮积症，其特征是一种称为蜡样质的脂色素在大脑中积聚。此外，MFSD8 突变最近与额颞叶痴呆 (FTD) 相关，其他 BD 相关基因与帕金森病 (ATP13A2) 和其他 FTD 亚型（GRN、CTSD）相关。 CLN7 BD 属于更广泛的儿科疾病类别，称为神经元蜡样质脂褐质沉积症 (NCL)，其具有神经元蜡样质积累的共同组织病理学特征和神经系统症状，包括痴呆、失明、癫痫发作和过早死亡。 MFSD8 基因编码 CLN7 蛋白，这是一种定位于溶酶体的功能未知的膜蛋白。导致 CLN7 BD 的突变是功能丧失，许多已知突变会导致过早停止或点突变，从而破坏蛋白质的稳定性。我们之前对患者成纤维细胞的研究表明，CLN7 的缺失会降低溶酶体水解酶活性、自噬通量和自发荧光物质的积累。虽然这些研究有助于我们了解 CLN7 如何导致疾病，但导致神经退行性变的机制尚不清楚。此外，还没有对相关患者来源的神经元模型进行研究。在这里，我们建议使用来自不同 BD 患者的几种 iPSC 系来探索 CLN7 突变引起的神经毒性机制。我们的初步数据表明 CLN7 BD 系可以在体外发育成皮质神经元，但表现出溶酶体表型和神经突延伸减少。在目标 1 中，我们计划使用这个已建立的神经元模型来确定 CLN7 的丢失如何影响蛋白质组的稳定性和蛋白质溶解度，以发现新的途径并生成关于 CLN7 BD 中细胞死亡如何发生的假设。在目标 2 中，我们将评估旨在恢复 CLN7 神经元蛋白质稳态的救援机制，以及将野生型星形胶质细胞与 CLN7-BD 神经元共培养，以评估神经胶质细胞在痴呆中的作用。由于几乎不知道 CLN7 如何导致神经功能障碍的机制信息，我们的研究有可能发现 CLN7 BD 和其他具有相似病理学的 NCL 的新治疗途径。除了 NCL 之外，MFSD8 的突变与 FTD（一种与年龄相关的神经退行性疾病）相关，因此我们的研究可能与更常见的与年龄相关的神经退行性疾病相关。由于越来越多的证据表明溶酶体功能障碍是常见散发性疾病，包括帕金森病和其他突触核蛋白病，因此我们的研究可能会对该领域产生广泛的影响。