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CRMP2, mitochondria, and Huntington’s disease

CRMP2、线粒体和亨廷顿病

基本信息

批准号：
9884828
负责人：
Nickolay Brustovetsky
金额：
$ 56.1万
依托单位：
INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-04-01 至 2022-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9884828
关键词：
Alzheimer&apos s Disease Animal Model Area Autopsy Behavior Behavioral Binding Brain Cell Death Cells Confocal Microscopy Corpus striatum structure Data Defect Development Disease Down-Regulation Dynamin Dynein ATPase Foundations Functional disorder Goals Human Huntington Disease Huntington gene Huntington protein Impairment Kinesin Knock-in Laboratories Lead Link Literature Mediating Mitochondria Mitochondrial Proteins Molecular Morphology Motor Mus Mutation Nerve Neurites Neurodegenerative Disorders Neurons Outer Mitochondrial Membrane Parkinson Disease Pathogenesis Pathology Pathway interactions Patients Phosphorylation Play Protein Dephosphorylation Protein Inhibition Protein phosphatase Proteins Regulation Research Role Side Small Interfering RNA Solid Testing Time Tissues Transgenic Organisms Transmission Electron Microscopy axon guidance base behavioral study cell motility cognitive function collapsin response mediator protein-2 effective therapy experimental study improved in vivo induced pluripotent stem cell mouse model mutant neuron loss neuronal cell body neuronal survival neuropathology novel novel therapeutics prevent protein protein interaction response small molecule

项目摘要

Mitochondrial dynamics, manifest as ability of mitochondria to change morphology and motility, play a vital role in neuronal response to fluctuating energy demands. Impairment of mitochondrial dynamics contributes to different disorders such as Alzheimer’s, Parkinson’s, and Huntington’s diseases (HD). In HD, interaction of mutant huntingtin (mHtt) with dynamin related protein 1 (Drp1) results in an increased Drp1 activity, leading to augmented mitochondrial fission, accompanied by reduced mitochondrial traffic. Despite significant effort, the molecular mechanisms, leading to mHtt-induced changes in mitochondrial morphology and motility are not completely understood. In preliminary experiments, we found that CRMP2, a protein implicated in axon guidance and regulation of neurite outgrowth, regulates mitochondrial dynamics. A mechanistic link between CRMP2 and regulation of mitochondrial dynamics has never been investigated. CRMP2 binds to neuronal mitochondria and in its dephosphorylated form to mHtt. CRMP2 physically interacts with Drp1, Mitofusin 2, and Miro 2, proteins involved in regulation of mitochondrial fission, fusion, and motility, respectively. Downregulation of CRMP2 with siRNA leads to increased fission and reduced mitochondrial traffic, implicating CRMP2 in regulation of mitochondrial dynamics. CRMP2 hyperphosphorylation after inhibition of protein phosphatases 1 and 2A correlates with augmented fission and reduced mitochondrial traffic. Conversely, decreasing CRMP2 phosphorylation can prevent these alterations. Finally, we found CRMP2 downregulation and hyperphosphorylation in striatal tissues from YAC128 HD mouse model and in postmortem striatal tissues of HD patients. Overall, the literature and our preliminary data strongly suggest that CRMP2 is involved in regulation of mitochondrial morphology and motility and CRMP2 hyperphosphorylation contributes to HD pathogenesis leading to excessive fission, reduced mitochondrial traffic, and neuronal loss. Dephosphorylated CRMP2 binds to mHtt and to proteins involved in mitochondrial dynamics and reduces their activities, whereas CRMP2 downregulation and hyperphosphorylation disrupts these protein-protein interactions, liberates binding partners of CRMP2, and increases their activities. In Aim 1, we will determine CRMP2 localization in mitochondria, establish protein interaction partners, and assess the extent to which CRMP2 regulates mitochondrial dynamics in neurons. In Aim 2, the mechanisms of CRMP2-medited regulation of mitochondrial dynamics will be determined. In Aim 3, we will establish CRMP2-mediated mechanisms contributing to defects of mitochondrial dynamics and cell death in human neurons expressing mHtt. Finally, in Aim 4, we will assess to what extent CRMP2 dephosphorylation alters protein-protein interactions, protects neurons, and corrects behavioral deficits in animal models of HD. The proposed study will considerably improve our understanding of HD pathophysiology, lay a solid foundation for identifying new mechanisms of HD pathogenesis, and open novel avenues in HD research.

线粒体动力学，表现为线粒体改变形态和运动的能力，发挥着至关重要的作用神经元对能量需求波动的反应。线粒体动力学受损有助于不同的疾病，如阿尔茨海默病、帕金森病和亨廷顿病 (HD)。在高清中，交互突变亨廷顿蛋白 (mHtt) 与动力相关蛋白 1 (Drp1) 导致 Drp1 活性增加，从而导致线粒体裂变增强，同时线粒体交通减少。尽管付出了巨大努力，导致 mHtt 诱导的线粒体形态和运动变化的分子机制不是完全明白了。在初步实验中，我们发现CRMP2，一种与轴突有关的蛋白质指导和调节神经突生长，调节线粒体动力学。之间的机械联系 CRMP2 和线粒体动力学的调节从未被研究过。 CRMP2 与神经元结合线粒体及其去磷酸化形式的 mHtt。 CRMP2 与 Drp1、Mitofusin 2 发生物理相互作用， Miro 2，分别参与线粒体裂变、融合和运动调节的蛋白质。用 siRNA 下调 CRMP2 会导致裂变增加和线粒体交通减少，这意味着 CRMP2 调节线粒体动力学。抑制蛋白后CRMP2过度磷酸化磷酸酶 1 和 2A 与裂变增强和线粒体流量减少相关。反过来，减少 CRMP2 磷酸化可以防止这些改变。最后，我们发现CRMP2下调 YAC128 HD 小鼠模型的纹状体组织和死后纹状体组织中的过度磷酸化的 HD 患者。总体而言，文献和我们的初步数据强烈表明 CRMP2 参与线粒体形态和运动的调节以及 CRMP2 过度磷酸化有助于 HD 发病机制导致过度裂变、线粒体交通减少和神经元损失。去磷酸化的 CRMP2 与 mHtt 和参与线粒体动力学的蛋白质结合，并减少它们的活性。活性，而 CRMP2 下调和过度磷酸化会破坏这些蛋白质-蛋白质相互作用，释放 CRMP2 的结合伙伴，并增加其活性。在目标 1 中，我们将确定 CRMP2 在线粒体中定位，建立蛋白质相互作用伙伴，并评估其作用程度 CRMP2 调节神经元中的线粒体动力学。在目标 2 中，CRMP2 介导的调节机制将确定线粒体动力学。在目标3中，我们将建立CRMP2介导的机制导致表达 mHtt 的人类神经元线粒体动力学缺陷和细胞死亡。最后，在目标 4，我们将评估 CRMP2 去磷酸化在多大程度上改变蛋白质-蛋白质相互作用、保护神经元，并纠正 HD 动物模型的行为缺陷。拟议的研究将大大提高我们对HD病理生理学的认识，为识别HD的新机制奠定坚实的基础 HD 发病机制，并为 HD 研究开辟新途径。