Neuronal cell-cycle re-entry and neurodegeneration

神经元细胞周期重入和神经变性

基本信息

批准号：
10659116
负责人：
Thomas E. Lloyd
金额：
$ 65.97万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-15 至 2025-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10659116
关键词：
Adult Age Alzheimer&apos s Disease Alzheimer&apos s disease model Alzheimer&apos s disease patient Animals Antimitotic Agents Automobile Driving Autopsy Biological Assay Biological Models C9ORF72 Cell Cycle Cell Cycle Inhibition Cell membrane Cells Cessation of life Cyclin D1 Development Disease Drosophila cyclin D Drosophila genus Embryonic Development Enzymes Event Excision Exhibits Failure Functional disorder G1/S Transition GPI Membrane Anchors Genes Genetic Genetic Suppression Genetic study Glycosylphosphatidylinositols Human Huntington Disease Impairment Induced pluripotent stem cell derived neurons Knockout Mice Lamin Type A Life Link Maintenance Mediating Membrane Mitosis Mitotic Mitotic Cell Cycle Modeling Molecular Mus Nerve Degeneration Nervous System Neurodegenerative Disorders Neurons Nuclear Envelope Nuclear Pore Complex Nuclear Pore Complex Proteins Outcome Pathogenesis Pathology Pathway interactions Patients Peptide Initiation Factors Physiological Process Proteins Regulatory Pathway Reporter Signal Transduction Spatial Distribution Specificity System Testing Therapeutic Intervention Tissues Visualization WNT Signaling Pathway Work cellular pathology design effective therapy fly frontotemporal lobar dementia amyotrophic lateral sclerosis glycerophosphodiester phosphodiesterase human disease induced pluripotent stem cell insight neuron loss neuronal survival new therapeutic target novel nucleocytoplasmic transport postmitotic preservation prevent progenitor progressive neurodegeneration protein transport segregation stem cells trafficking transcriptome sequencing

项目摘要

Two causal mechanisms of neurodegeneration that are found in Alzheimer's disease (AD) and AD-related diseases such as amyotrophic lateral sclerosis-frontotemporal dementia (ALS-FTD) are re-initiation of the mitotic cell-cycle in neurons, and impaired nucleocytoplasmic trafficking resulting from disruptions in the nuclear envelope (NE) and nuclear pore complex (NPC). Deeper insight into how these abnormalities arise would clarify approaches to design effective treatments for these diseases; however, very little is known about the initiating mechanisms involved. This application will test the hypothesis that neuronal quiescence is maintained throughout life via active mechanisms that inhibit the mitotic cell-cycle and that re-initiation of the cell-cycle leads to NE/NPC disassembly, a normal occurrence in mitotic cells. This hypothesis is based on our study of the six-transmembrane enzyme GDE2 (Glycerophosphodiester phosphodiesterase 2; GDPD5), which cleaves the GPI-(Glycosylphosphatidylinositol)-anchor that tethers some proteins to the plasma membrane. GDE2 is a potent inhibitor of the mitotic cell-cycle and induces the differentiation of mitotic progenitors into post-mitotic neurons in the developing nervous system. We discovered that in adult mice lacking GDE2 (Gde2 KO), cortical neurons show evidence of cell-cycle re-entry, suggesting that GDE2 is required to preserve neurons in a quiescent state. Strikingly, Gde2 KO neurons that have re-entered the cell-cycle show abnormal organization of the NE, aberrant distribution of NPC proteins and impaired nucleocytoplasmic transport, raising the possibility that cell-cycle re-initiation and NE/NPC breakdown are linked. Consistent with this idea, genetic reduction of cyclin D, a critical regulator of the G1/S transition, suppresses nucleocytoplasmic transport-dependent neurodegeneration in a Drosophila model of c9ORF72 ALS-FTD. Notably, Gde2 KO mice display age-progressive neurodegeneration and GDE2 distribution and function is disrupted in AD patient neurons. These observations suggest that maintenance of neuronal quiescence is an active process and that failure of this process re-initiates the cell-cycle, triggers NE/NPC breakdown and induces neurodegeneration. Aim 1 will determine if GDE2 encodes a new pathway that maintains neuronal quiescence and will determine if neuronal cell-cycle re-entry signals NE/NPC breakdown in neurons. Preliminary RNAseq, analysis of Wnt-reporter mice in Gde2 KOs, and genetic studies in Drosophila identify aberrant activation of canonical Wnt signaling as a candidate pathway that induces neuronal cell-cycle re-entry, NE/NPC breakdown and neurodegeneration. Aim 2 will utilize mouse and Drosophila models to test this hypothesis. Studies in Aim 3 will determine links between GDE2 dysfunction, neuronal cell-cycle re-entry and NE/NPC breakdown in disease using Drosophila models of AD and ADRD, human postmortem tissue and iPS human neurons. These studies will provide new molecular insight into cross-disease triggers of neurodegeneration important in human AD and ADRDs.

阿尔茨海默病 (AD) 和 AD 相关神经退行性疾病的两种因果机制肌萎缩侧索硬化症-额颞叶痴呆 (ALS-FTD) 等疾病是有丝分裂的重新启动神经元的细胞周期，以及核细胞破坏导致的核细胞质运输受损包膜（NE）和核孔复合体（NPC）。更深入地了解这些异常是如何发生的将澄清为这些疾病设计有效治疗方法的方法；然而，人们对发起者知之甚少涉及的机制。该应用程序将测试神经元保持静止的假设通过抑制有丝分裂细胞周期和细胞周期重新启动的主动机制在整个生命过程中 NE/NPC 分解，这是有丝分裂细胞中的正常现象。这一假设基于我们对六次跨膜酶 GDE2（甘油磷酸二酯磷酸二酯酶 2；GDPD5）的研究，该酶可裂解将某些蛋白质束缚在质膜上的 GPI-（糖基磷脂酰肌醇）锚。 GDE2 是一个强大的有丝分裂细胞周期的抑制剂并诱导有丝分裂祖细胞分化为有丝分裂后神经元正在发育的神经系统。我们发现，在缺乏 GDE2（Gde2 KO）的成年小鼠中，皮质神经元显示细胞周期重新进入的证据，表明需要 GDE2 来保持神经元处于静止状态。引人注目的是，重新进入细胞周期的 Gde2 KO 神经元显示出 NE 的异常组织，异常 NPC 蛋白的分布和核细胞质运输受损，增加了细胞周期重新启动和 NE/NPC 分解之间存在联系的可能性。与这一观点一致，细胞周期蛋白 D 的遗传减少是一个关键因素。 G1/S 转换的调节因子，抑制核细胞质转运依赖性神经变性 c9ORF72 ALS-FTD 的果蝇模型。值得注意的是，Gde2 KO 小鼠表现出年龄进行性神经退行性变 AD 患者神经元中 GDE2 的分布和功能受到破坏。这些观察表明神经元静止的维持是一个活跃的过程，该过程的失败会重新启动细胞周期，触发 NE/NPC 分解并诱导神经变性。目标 1 将确定 GDE2 是否编码维持神经元静止并将确定神经元细胞周期重入信号是否存在的新途径神经元中的 NE/NPC 分解。初步 RNAseq、Gde2 KO 中 Wnt 报告基因小鼠的分析以及遗传果蝇研究发现经典 Wnt 信号传导的异常激活是诱导神经元细胞周期重入、NE/NPC 分解和神经变性。目标 2 将使用鼠标并果蝇模型来检验这一假设。目标 3 的研究将确定 GDE2 功能障碍之间的联系，使用 AD 和 ADRD 的果蝇模型进行疾病中的神经元细胞周期重入和 NE/NPC 分解，人类死后组织和 iPS 人类神经元。这些研究将为人类 AD 和 ADRD 中重要的神经变性的跨疾病触发因素提供新的分子见解。