Role of Prion Protein in Manganese Neurotoxicity

朊病毒蛋白在锰神经毒性中的作用

基本信息

批准号：
8494047
负责人：
Anumantha Gounder Kanthasamy
金额：
$ 67.27万
依托单位：
IOWA STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-07-09 至 2015-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8494047
关键词：
Address Affinity Animal Model Animals Antioxidants Apoptosis Apoptotic Attenuated Basal Ganglia Binding Binding Proteins Binding Sites Biological Assay Blood Bovine Spongiform Encephalopathy Brain Brain Diseases Brain region Cell Adhesion Cell Adhesion Molecules Cell Culture Techniques Cell Death Cell physiology Cells Chronic Chronic Wasting Disease Copper Data Deer Digestion Disease Divalent Cations Dose Endopeptidase K Environmental Exposure Etiology Exposure to Figs - dietary Genetic Transcription Heat shock proteins Homeostasis Human Infection Investigation Knockout Mice Link Mammals Manganese Metalloproteins Metals Mitochondria Modeling Mus Nerve Degeneration Neurodegenerative Disorders Neurologic Neurons Organism Oxidative Stress Pathogenesis Pathologic Processes Peptide Hydrolases Play PrP PrPSc Proteins Prion Diseases Prions Protein Region Proteins Reporting Research Resistance Role Scrapie Seeds Severities Signal Transduction Slice Staging Stress Structure Testing Time Transducers Transgenic Animals Transgenic Mice Transgenic Model Transition Elements Up-Regulation Zinc conformational conversion divalent metal insight mitochondrial dysfunction mouse model mutant neurochemistry neurotoxicity novel overexpression oxidative damage particle protein aggregation protein function protein misfolding cyclic amplification public health relevance response stress protein

项目摘要

DESCRIPTION (provided by applicant): Environmental exposure to transition metals is linked to pathological processes of various neurodegenerative conditions since metal neurotoxicity often augments key degenerative changes including ionic imbalance, oxidative stress and protein aggregation. Several metal binding proteins regulate intracellular metal homeostasis and thereby maintain normal cellular function. Emerging evidence indicates that prion proteins are metal binding proteins that can efficiently bind to certain divalent cations including copper and manganese at the octapeptide repeat regions of the protein. Therefore, dysregulation of metal homeostasis has been suggested to play a role in the pathogenesis of prion diseases. Recent observations of elevated manganese (Mn) levels in the brain and blood of humans and animals afflicted with prion diseases suggest that manganese neurotoxicity may play a role in the etiology of prion diseases. Recently, we demonstrated that normal prion protein effectively attenuates manganese transport into neuronal cells and protects against manganese-induced oxidative stress, mitochondrial dysfunction, cellular antioxidant depletion, and apoptosis. While investigating these mechanisms, we unexpectedly found that manganese treatment upregulates cellular prion levels independent of transcription. Furthermore, we found manganese increases stability, suggesting that prion protein may promote the conversion of normal prion protein (PrPC) to the pathological form of prion (PrPSc), which results in the loss of normal prion protein's protective function against manganese neurotoxicity. Thus, the central hypothesis of this proposal is that manganese binds to the octapeptide (PHGGGWGQ) domain of cellular prion protein to increase the stability and accumulation of the protein. Manganese-induced stabilization of prion protein accelerates conformational conversion of PrPC to proteinase-resistant prion protein (PrPSc) aggregates and thereby induces neurotoxicity. This novel hypothesis will be tested through a systematic investigation of the following specific aims: i) to determine whether chronic exposure to manganese increases prion protein accumulation in animal models, ii) to determine the role of octapeptide repeat sequences in the manganese-induced stabilization of prion protein, iii) to determine whether chronic manganese exposure accelerates the accumulation and aggregation of the scrapie form of prion protein (PrPSc) and causes increased neuronal damage in a mouse model of prion disease, iv) to compare the effect of manganese on the accumulation and aggregation of PrPSc and on neuronal damage in mouse scrapie-infected prion overexpressing and octapeptide deletion transgenic animals (Tg20 and TgPrPDOR transgenic mice). Together, results from the proposed studies will not only provide new insights into the role of prion protein in manganese neurotoxicity but also will advance understanding of the role of metals in the pathogenesis of prion diseases.

描述（由申请人提供）：环境暴露于过渡金属与各种神经退行性条件的病理过程有关，因为金属神经毒性通常会增加关键的退化性变化，包括离子不平衡，氧化应激和蛋白质聚集。几种金属结合蛋白调节细胞内金属稳态，从而保持正常的细胞功能。新兴的证据表明，prion蛋白是金属结合蛋白，可以有效地与某些二价阳离子结合，包括蛋白质的八肽重复区域，包括铜和锰。因此，已经提出金属稳态的失调在病毒疾病的发病机理中发挥作用。最近对患有prion疾病的人类和动物的脑和血液中锰（MN）水平升高的观察结果表明，锰神经毒性可能在病毒疾病的病因学中起作用。最近，我们证明了正常的prion蛋白有效地减弱了锰转运到神经元细胞中，并预防锰诱导的氧化应激，线粒体功能障碍，细胞抗氧化剂耗竭和凋亡。在研究这些机制时，我们出乎意料地发现，锰的治疗上调了与转录无关的细胞pr虫水平。此外，我们发现锰提高了稳定性，这表明prion蛋白可能会促进正常prion蛋白（PRPC）转化为病毒的病理形式（PRPSC），这导致正常prion蛋白蛋白针对锰神经毒性的保护功能的丧失。因此，该提议的中心假设是锰与细胞prion蛋白的八肽（PhggGWGQ）结合，以增加蛋白质的稳定性和积累。锰诱导的prion蛋白的稳定化加速了PRPC向抗蛋白酶耐药蛋白（PRPSC）聚集的构象转化，从而诱导神经毒性。这一新的假设将通过对以下特定目的进行系统研究来测试：i）确定慢性暴露于锰在动物模型中增加prion蛋白的积累，ii）确定八肽重复序列在锰诱导的prion蛋白稳定中的作用，以确定在prion蛋白的稳定中，iii是否会累积慢性含量的繁殖（均占据量的繁殖量）。并导致在小鼠疾病的小鼠模型中增加神经元损伤，iv）比较锰对PRPSC的积累和聚集的影响以及在小鼠crapie感染的prion中对过表达的小鼠crapie prion和八肽缺失转基因动物（TG20和TGPRPDOR转基因小鼠）的影响。总之，拟议的研究的结果不仅将提供有关prion蛋白在锰神经毒性中的作用的新见解，而且还将提高人们对金属在prion疾病发病机理中的作用的理解。