Mechanisms of LRRK2 Mediated Neurotoxicity

LRRK2 介导的神经毒性机制

• 批准号: 9883049
• 负责人: Andrew B West
• 金额: $ 35万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-11-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9883049
• 关键词: Actins; Binding; Brain; Brain Diseases; Cells; Chemotaxis; Complex; Disease; Disease Progression; Dissection; Electron Microscopy; F-Actin; Frequencies; Genes; Genetic; Guanosine Triphosphate Phosphohydrolases; HIV; Individual; Inflammatory; Interferon Type II; Knock-out; LRRK2 gene; Link; Mass Spectrum Analysis; Mediating; Microfilaments; Missense Mutation; Modeling; Morbidity - disease rate; Mus; Mutation; Myeloid Cells; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Parkinson Disease; Pathogenicity; Pathway interactions; Patients; Phosphotransferases; Primary Cell Cultures; Production; Proteins; Reactive Oxygen Species; Role; Stimulus; TNF gene; Technology; Testing; Toxic effect; Transgenic Organisms; Treatment Efficacy; United States; Wild Type Mouse; Work; alpha synuclein; base; cell motility; cytokine; genetic regulatory protein; imaging approach; inhibitor/antagonist; insight; kinase inhibitor; live cell imaging; mortality; mutation carrier; neuroprotection; neurotoxic; neurotoxicity; new therapeutic target; novel; overexpression; oxidative damage; polymerization; protein complex; protein expression; public health relevance; recruit; response; scaffold; selective expression; therapeutic evaluation

DESCRIPTION (provided by applicant): Parkinson disease (PD) is the second most common neurodegenerative disorder. More than 10 million individuals worldwide are expected to have PD by the year 2030, and currently there are no known therapies that slow or halt the relentless progression of the disease. Dominant missense mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common known cause of PD, with up to 40 to 60 thousand carriers of the pathogenic G2019S-LRRK2 mutation in the United States. In individuals of Ashkenazi or Berber descent, frequencies of the G2019S-LRRK2 mutation can be as high as 20-30% in PD patients. In our last project period, we demonstrated that G2019S- LRRK2 expression promotes dopaminergic neurodegeneration caused by α-synuclein over- expression and that LRRK2 kinase inhibitors blocked these effects. However, the mechanisms linking LRRK2 to α-synuclein neurotoxicity are not clear. Further dissection of LRRK2 action in PD may expedite the discovery of new therapies that target LRRK2 and related pathways for neuroprotection. We found that LRRK2 is expressed in many neurons tougher with α-synuclein in healthy brains, but in diseased brains that have α-synuclein inclusions, LRRK2 is also expressed in myeloid cells that can direct the production of neurotoxic cytokines and reactive-oxygen species. In this competitive renewal request, we hypothesize that LRRK2 expression and kinase activity promotes myeloid cell recruitment to neurons that have α-synuclein inclusions to exacerbate neurodegeneration and the spread of α-synuclein inclusions. Using conditional transgenics that inducibly over-express G2019S-LRRK2 in myeloid cells, we will test whether G2019S-LRRK2 can upregulate cytokine responses and oxidative damage caused by neuronal α-synuclein inclusions through promoting myeloid cell recruitment. Using conditional deletion technology, we will test whether LRRK2 knockout in myeloid cells will downregulate neurotoxic cytokines and oxidative damage in response to α-synuclein inclusions through inhibiting myeloid cell recruitment. We will explore how LRRK2 protein can control myeloid cell motility and chemotaxis by acting as a novel scaffold for Arp2/3 to control actin polymerization. We predict that LRRK2 interacts with Arp2/3, in a kinase-dependent manner, to facilitate actin microspikes at the leading front of mobile myeloid cells to enhance motility. Completion of these studies should allow for further insight into how LRRK2 can cause PD, how LRRK2 expression in myeloid cells might contribute to neurodegeneration, and definition of a novel actin nucleation complex important for myeloid cell chemotaxis.

描述（由申请人提供）：帕金森病（PD）是第二常见的神经退行性疾病。到2030年，全球预计将有超过1000万人患有帕金森病，目前还没有已知的治疗方法可以减缓或阻止这种疾病的持续发展。富亮氨酸重复激酶2 （LRRK2）基因的显性错义突变是PD最常见的已知原因，在美国有多达4万至6万名致病G2019S-LRRK2突变携带者。在德系犹太人或柏柏尔人后裔中，PD患者中G2019S-LRRK2突变的频率可高达20-30%。在我们的上一个项目期间，我们证明了G2019S- LRRK2表达促进α-突触核蛋白过表达引起的多巴胺能神经变性，而LRRK2激酶抑制剂阻断了这些作用。然而，LRRK2与α-突触核蛋白神经毒性的联系机制尚不清楚。进一步解剖LRRK2在PD中的作用可能会加速发现针对LRRK2和相关神经保护途径的新疗法。我们发现LRRK2在健康大脑中许多含有α-突触核蛋白的神经元中表达，但在含有α-突触核蛋白内含物的病变大脑中，LRRK2也在髓细胞中表达，髓细胞可以指导神经毒性细胞因子和活性氧的产生。在这种竞争性更新要求中，我们假设LRRK2的表达和激酶活性促进髓细胞向含有α-突触核蛋白包涵体的神经元募集，从而加剧神经变性和α-突触核蛋白包涵体的扩散。通过条件转基因诱导髓细胞过表达G2019S-LRRK2，我们将测试G2019S-LRRK2是否通过促进髓细胞募集来上调细胞因子反应和神经元α-突触核蛋白包涵体引起的氧化损伤。使用条件删除技术，我们将测试在髓细胞中敲除LRRK2是否会通过抑制髓细胞募集来下调α-突触核蛋白包涵体对神经毒性细胞因子和氧化损伤的反应。我们将探索LRRK2蛋白如何通过作为Arp2/3的新型支架来控制肌动蛋白聚合，从而控制髓细胞的运动和趋化性。我们预测LRRK2以激酶依赖的方式与Arp2/3相互作用，促进运动髓细胞前部的肌动蛋白微尖峰，以增强运动性。这些研究的完成将有助于进一步了解LRRK2如何导致PD，髓细胞中LRRK2表达如何导致神经退行性变，以及定义一种对髓细胞趋化性重要的新型肌动蛋白成核复合物。