ProSAAS-mediated neuroprotective mechanisms in Alzheimer's and Parkinson's diseases: the role of secretory chaperones in neurodegeneration

ProSAAS 介导的阿尔茨海默病和帕金森病的神经保护机制：分泌伴侣在神经退行性变中的作用

• 批准号: 10062465
• 负责人: IRIS LINDBERG
• 金额: $ 63.37万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-02-01 至 2023-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10062465
• 关键词: Affect; Alzheimer' s Disease; Alzheimer' s disease model; Alzheimer' s disease related dementia; American; Amyloid; Amyloid beta-Protein; Amyloid deposition; Animal Model; Attenuated; Biochemical; Brain; Cell Line; Cell model; Cells; Client; Corpus striatum structure; Coupled; Cultured Cells; Cytopathology; Cytoplasmic Granules; Cytoprotection; Deposition; Development; Disease; Disease model; Dopamine; Endocrine; Exhibits; Frequencies; Health; Healthcare Systems; Hippocampus (Brain); Homeostasis; In Vitro; Individual; Laboratories; Location; Maintenance; Mediating; Midbrain structure; Modeling; Molecular Chaperones; Motor; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Parkinson Disease; Pathogenicity; Pathology; Pathway interactions; Patients; Peptides; Periodicity; Pick Disease of the Brain; Play; Process; Proteins; Proteomics; Rattus; Role; Scanning; Senile Plaques; Site; Speed; Substantia nigra structure; Synapses; Synaptic Vesicles; Testing; Toxic effect; Tyrosine 3-Monooxygenase; Viral; Work; abeta accumulation; alpha synuclein; amyloid pathology; brain tissue; cytotoxic; cytotoxicity; differential expression; dopaminergic neuron; experimental study; extracellular; immunoreactivity; in vivo; in vivo Model; inhibitor/antagonist; insight; knock-down; loss of function; mouse model; neuron loss; neuroprotection; neurotoxic; neurotoxicity; older patient; overexpression; potential biomarker; protein aggregation; proteostasis; small hairpin RNA; unpublished works

Demographic considerations predict an overwhelming burden on the U.S. health care system within the next few decades due to an influx of elderly patients with neurodegenerative disease. The most prevalent of these, Alzheimer's and Parkinson's diseases (AD and PD), are predicted to affect tens of millions of Americans by 2040. Both of these diseases involve progressively more aberrant brain proteostasis, associated with massive neuronal cell death. A variety of cytosolic and secreted brain chaperones contribute to maintenance of neuronal proteostasis in these and other neurodegenerative proteinopathies; of these, the secretory chaperone proSAAS has many compelling features. ProSAAS is expressed only in neurons and endocrine cells; because it traffics through the regulated secretory pathway, it becomes concentrated within dense core synaptic granules, and is released during neuronal activity. ProSAAS has been identified by five proteomics groups as a potential biomarker in neurodegenerative disease, and is found associated with aggregated proteins in the substantia nigra of PD patients as well as with amyloid plaques in AD‐affected individuals. ProSAAS blocks the aggregation of both Abeta and alpha synuclein at highly substoichiometric ratios, and both endogenous overexpression as well as exogenous application reduce Abeta‐ and alpha synuclein‐mediated neurotoxicity in primary neurons and cell lines. Most recently, we have shown that proSAAS overexpression is also functionally protective in vivo in a rat model of alpha‐synuclein overexpression. In the proposed work, we will investigate the likely common mechanisms by which proSAAS protects neurons from neurotoxic aggregating proteins and peptides such as alpha synuclein and Abeta 1‐42. We hypothesize that secreted proSAAS sequesters cytotoxic oligomers and fibrils extracellularly, reducing their concentrations at the synapse. Secondly, we hypothesize that endocytosed proSAAS acts intracellularly to similarly sequester cytotoxic proteins, speeding their degradation. Using cultured primary hippocampal and nigral neurons, we will determine whether proSAAS is involved in intracellular and extracellular Abeta and alpha synuclein sequestration. We will also determine whether intracellular expression of proSAAS confers a cytoprotective advantage compared to extracellular addition. Lastly we will assess whether endocytosed proSAAS accelerates the intracellular degradation of Abeta and alpha synuclein. In parallel, we will expand our exciting in vivo results to include the alpha‐synuclein preformed fibril model to tease apart the potential sites of action of proSAAS in substantia nigra and striatum. Pre‐degenerative changes in dopamine homeostasis, assessed using fast‐scan‐cyclic‐voltammetry, will be correlated with proSAAS‐mediated neuroprotection. Similarly, a mouse model of AD will be used to test the effects of proSAAS AAV‐mediated over‐ and underexpression on the development of amyloid pathology. Collectively, these experiments will provide insight into biochemical mechanisms underlying the potent cytoprotective effects of the proSAAS chaperone protein.

人口因素预测美国医疗保健系统将承受巨大的负担 在接下来的几十年里，由于患有神经退行性疾病的老年患者的涌入。 其中流行的阿尔茨海默病和帕金森病（AD 和 PD）预计将影响数十种疾病 到 2040 年，将有数百万美国人罹患这两种疾病。这两种疾病都涉及越来越多的大脑异常 蛋白质稳态，与大量细胞质和分泌性脑细胞死亡有关。 分子伴侣有助于维持这些和其他神经退行性疾病中的神经元蛋白质稳态 蛋白质病；其中，分泌伴侣 proSAAS 有许多引人注目的特征。 仅在神经元和内分泌细胞中表达；因为它通过受调节的分泌细胞进行运输； 途径，它集中在致密核心突触颗粒内，并在神经元过程中释放 ProSAAS 已被五个蛋白质组学小组确定为潜在的生物标志物。 神经退行性疾病，被发现与黑质中的聚集蛋白有关 PD 患者以及 AD 患者中存在淀粉样蛋白斑块的 ProSAAS 会阻断该作用。 Abeta 和 α 突触核蛋白以高度亚化学计量比聚集，并且两者 内源性过度表达以及外源性应用可减少原代神经元和细胞系中 Abeta 和 α 突触核蛋白介导的神经毒性。 在α-突触核蛋白过度表达的大鼠模型中，过度表达也具有体内功能保护作用。 在拟议的工作中，我们将研究 proSAAS 可能的常见机制 保护神经元免受神经毒性聚集蛋白和肽（例如 α 突触核蛋白和 Abeta）的侵害 1-42.我们爬升了分泌的proSAAS将细胞毒性寡聚体和原纤维隔离在细胞外， 其次，我们研究了内吞的 proSAAS 的作用。 使用培养物在细胞内类似地隔离细胞毒性蛋白，加速其降解。 原代海马和黑质神经元，我们将确定 proSAAS 是否参与 我们还将确定细胞内和细胞外的 Abeta 和 α 突触核蛋白隔离。 与相比，proSAAS 的细胞内表达是否具有细胞保护优势 最后我们将评估内吞的 proSAAS 是否加速细胞内的添加。 Abeta 和 α 突触核蛋白的降解。 与此同时，我们将扩大我们令人兴奋的体内结果，以包括预先形成的α-突触核蛋白 使用快速扫描循环伏安法评估多巴胺稳态的退行性变化，将使用原纤维模型来梳理黑质和纹状体中 proSAAS 的潜在作用位点。 与 proSAAS 介导的神经保护相关，类似地，AD 小鼠模型将用于研究。 测试 proSAAS AAV 介导的过度表达和表达不足对淀粉样蛋白形成的影响 总的来说，这些实验将提供对生化机制的深入了解。 proSAAS 伴侣蛋白强大的细胞保护作用的基础。