Mechanisms of Neuronal Maintenance and Protection.

神经元维持和保护机制。

• 批准号: 8489360
• 负责人: Rong Grace Zhai
• 金额: $ 31.65万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8489360
• 关键词: Address; Biochemical; Biological Models; Degenerative Disorder; Disease; Drosophila genus; Environmental Risk Factor; Enzymes; Epigenetic Process; Event; Genes; Genetic; Genetic Screening; Goals; Health; Heat-Shock Response; Heating; Hippocampus (Brain); Homeostasis; Homologous Gene; Housekeeping; Human; Indium; Life; Light; Maintenance; Mediating; Messenger RNA; Modeling; Molecular; Molecular Chaperones; Mus; Mutagenesis; Mutation; Nerve Degeneration; Nerve Regeneration; Nervous system structure; Neurons; Nicotinamide-Nucleotide Adenylyltransferase; Organism; Phototransduction; Process; Property; Protein Isoforms; Proteins; Regulation; Research; Retinal Degeneration; Role; Severities; Spinal Ganglia; Stress; Structure; System; Tertiary Protein Structure; Testing; Therapeutic; Time; Toxic effect; Transcriptional Regulation; Ubiquitination; Visual system structure; Wallerian Degeneration; Work; ataxin-1; base; design; effective therapy; genetic manipulation; insight; mouse model; neurotoxicity; overexpression; polyglutamine; promoter; protective effect; protein aggregation; protein degradation; protein folding; protein misfolding; receptor; repaired; research study

DESCRIPTION (provided by applicant): Neurodegeneration can be triggered by a variety of genetic, epigenetic, and environmental factors. Healthy neurons are able to maintain their integrity throughout the life of an organism, suggesting the existence of a maintenance mechanism that allows neurons to sustain, mitigate or even repair damage. Recently, we have identified a neuronal maintenance factor NMNAT in a forward genetic screen in Drosophila. Loss of nmnat causes rapid and severe neurodegeneration, whereas over-expression of NMNAT protein offers protection against neurodegeneration. These findings suggest that normal level of NMNAT maintains neuronal homeostasis, and increased level offers protection. NMNAT is a highly conserved housekeeping enzyme, and the neuroprotective function of NMNAT has also been implicated in a mouse model of slow Wallerian Degeneration. Currently, the detailed mechanisms of this maintenance function and the protective capability of NMNAT in mammalian neurons are unclear. Our preliminary experiments suggest that in addition to its NAD synthesis activity, NMNAT has a chaperone function that is involved in regulating protein misfolding and degradation. We hypothesize that like other chaperones, NMNAT is up-regulated under stress, reduces protein aggregation, and thus protects neurons from degenerative conditions. In the proposed research, we will characterize the biochemical and cellular mechanisms underlying the protective process mediated by NMNAT using both Drosophila and mammalian primary neuronal models. In Specific Aim 1, we will use structure- function analysis to define the protein domains that are required for chaperone function, and characterize the transcriptional regulation of NMNAT under stress. In Specific Aim 2, we will first determine the neuroprotective activity of mammalian NMNAT isoforms in primary neurons, and then characterize the role of NMNAT in reducing protein aggregation-induced neurotoxicity. In Specific Aim 3, we will test whether NMNAT proteins can exert protective activity when their expression is induced after the onset of degeneration. For this last study, we will take advantage of the Drosophila genetic system and control the expression of NMNAT using a heat-inducible promoter. In summary, our proposed research in both Drosophila and mammalian model systems will help unmask the function of NMNAT and its regulation as a molecular chaperone, determine the neuroprotective properties of human NMNAT in primary neurons, and reveal the repair potential of NMNAT in neural regeneration after neuronal damage.

描述（由申请人提供）：神经变性可由多种遗传、表观遗传和环境因素引发。健康的神经元能够在生物体的整个生命周期中保持其完整性，这表明存在一种维持机制，使神经元能够维持、减轻甚至修复损伤。最近，我们在果蝇的正向遗传筛选中发现了一种神经元维持因子NMNAT。nmnat的缺失导致快速和严重的神经退行性变，而nmnat蛋白的过度表达则对神经退行性变提供保护。这些结果表明，正常水平的NMNAT维持神经元稳态，而增加的水平则提供保护。NMNAT是一种高度保守的管家酶，NMNAT的神经保护功能也与小鼠慢性沃勒氏变性模型有关。目前，NMNAT在哺乳动物神经元中维持功能的具体机制和保护能力尚不清楚。我们的初步实验表明，NMNAT除了具有NAD合成活性外，还具有参与调节蛋白质错误折叠和降解的伴侣蛋白功能。我们假设，像其他伴侣一样，NMNAT在压力下被上调，减少蛋白质聚集，从而保护神经元免受退行性疾病的影响。在拟议的研究中，我们将利用果蝇和哺乳动物的初级神经元模型来表征NMNAT介导的保护过程的生化和细胞机制。在Specific Aim 1中，我们将使用结构-功能分析来定义伴侣功能所需的蛋白质结构域，并表征NMNAT在压力下的转录调控。在Specific Aim 2中，我们将首先确定哺乳动物NMNAT亚型在初级神经元中的神经保护活性，然后表征NMNAT在减少蛋白质聚集诱导的神经毒性中的作用。在Specific Aim 3中，我们将测试NMNAT蛋白在变性发生后被诱导表达时是否能发挥保护作用。在最后的研究中，我们将利用果蝇的遗传系统，利用热诱导启动子控制NMNAT的表达。总之，我们提出的在果蝇和哺乳动物模型系统中的研究将有助于揭示NMNAT的功能及其作为分子伴侣的调控，确定人类NMNAT在初级神经元中的神经保护特性，揭示NMNAT在神经元损伤后神经再生中的修复潜力。

项目成果

Nicotinamide mononucleotide adenylyltransferase maintains active zone structure by stabilizing Bruchpilot.

烟酰胺单核苷酸腺苷酸转移酶通过稳定 Bruchpilot 来维持活性区结构。

• DOI: 10.1038/embor.2012.181
• 发表时间: 2013
• 期刊: EMBO reports
• 影响因子: 7.7
• 作者: Zang,Shaoyun;Ali,YousufO;Ruan,Kai;Zhai,RGrace
• 通讯作者: Zhai,RGrace

Alternative splicing of Drosophila Nmnat functions as a switch to enhance neuroprotection under stress.

• DOI: 10.1038/ncomms10057
• 发表时间: 2015-11-30
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Ruan K;Zhu Y;Li C;Brazill JM;Zhai RG
• 通讯作者: Zhai RG

Protein aggregates are recruited to aggresome by histone deacetylase 6 via unanchored ubiquitin C termini.

• DOI: 10.1074/jbc.m111.273730
• 发表时间: 2012-01-20
• 期刊: The Journal of biological chemistry
• 作者: Ouyang H;Ali YO;Ravichandran M;Dong A;Qiu W;MacKenzie F;Dhe-Paganon S;Arrowsmith CH;Zhai RG
• 通讯作者: Zhai RG

The role of autophagy in Nmnat-mediated protection against hypoxia-induced dendrite degeneration.

• DOI: 10.1016/j.mcn.2012.11.008
• 发表时间: 2013-01
• 期刊: Molecular and cellular neurosciences
• 作者: Wen Y;Zhai RG;Kim MD
• 通讯作者: Kim MD