Genetic analysis and regulation of amyloids flux in the Drosophila heart

描述（由申请人提供）：几种人类疾病与突变的、错误折叠的和易于聚集的淀粉样蛋白的表达有关.这些淀粉样蛋白的沉积、它们的增殖或多聚化导致几种神经病的发生，包括阿尔茨海默病和亨廷顿病。淀粉样蛋白在人类心脏中的积累导致心肌病。尽管有几种蛋白质被证明与心脏淀粉样变性有关，但导致这种疾病的确切机制却知之甚少。最近的证据表明，患有亨廷顿氏病和阿尔茨海默氏病的患者表现出更高的心血管事件发生率，但对这些疾病如何导致心力衰竭知之甚少。由于许多蛋白质依赖于细胞折叠环境，我们假设心脏中引起HD或AD的淀粉样蛋白的表达将由于氧化应激或整体错误折叠而破坏蛋白质折叠质量控制的整体平衡，导致组织功能丧失。为了验证我们的假设，我们将使用遗传上易处理的模式生物黑腹果蝇，并采用综合方法探索和抑制心脏淀粉样变性。我们建议开发第一个果蝇模型来研究与阿尔茨海默氏症和亨廷顿氏病相关的心脏缺陷。使用UAS-Gal 4表达系统，我们将在果蝇心脏中表达UAS-聚谷氨酰胺（用于亨廷顿病）和UAS-A242肽（用于阿尔茨海默病）。我们将在生理和细胞生物学水平上研究由此产生的心脏缺陷。此外，我们将探讨淀粉样蛋白在心肌中的表达如何影响自噬和其他应激标志物的表达。然后我们计划使用遗传学和药理学方法来抑制心脏淀粉样变性。将尝试通过过表达伴侣蛋白来减少整体蛋白质展开或超氧化物歧化酶来改善氧化应激，从而遗传抑制淀粉样蛋白诱导的心肌病。我们也将探讨药物如伴侣诱导剂或抗氧化剂对改善淀粉样蛋白积聚相关的心脏缺陷的作用。 我们提出的研究生物，果蝇，其高度的基因保守的人类基因组和许多技术来操纵其基因表达，将是一个很好的模式，探索在阿尔茨海默氏症和亨廷顿氏病患者的心力衰竭的机制，并可能被证明是有用的开发人类疾病的治疗方法。最终，一旦建立，该模型可用于探索与其他淀粉样前体蛋白相关的心脏淀粉样变性的发生和抑制。因此，该建议具有广泛的应用，并且适用于心脏病、阿尔茨海默病和亨廷顿病。这三种疾病都是毁灭性的，这项研究的结果可能为它们的起源提供重要线索。 公共卫生相关性：阿尔茨海默病和亨廷顿病都是心力衰竭的主要危险因素;拟议的研究首次使用模式生物果蝇来探索这两种主要神经退行性疾病中淀粉样蛋白诱导的心功能障碍。我们将使用转基因和药理学方法来抑制诱导的心脏淀粉样变性。这项研究对于理解两种主要神经病变中心力衰竭的机制至关重要，一旦建立，这种果蝇模型可用于探索与其他淀粉样前体蛋白相关的淀粉样蛋白诱导的心力衰竭。

DESCRIPTION (provided by applicant): Several human diseases are associated with the expression of mutated, misfolded and aggregation- prone amyloid proteins. Deposition of these amyloids, their proliferation or multimerization leads to the genesis of several neuropathies, including Alzheimer's and Huntington's diseases. Accumulation of amyloids in the human heart leads to cardiomyopathy. Despite several proteins being shown to be associated with cardiac amyloidosis, the precise mechanism that leads to the disease is poorly known. Recent evidence indicates that patients with Huntington's and Alzheimer's diseases demonstrate a greater occurrence of cardiovascular events but very little is known as to how these diseases lead to cardiac failure. Since many proteins are dependent on the cellular folding environment, we hypothesize that expression of HD- or AD-causing amyloids in the heart will disrupt the overall balance of protein folding quality control due to oxidative stress or global misfolding, resulting in loss of tissue function. To test our hypothesis, we will use the genetically tractable model organism Drosophila melanogaster and employ an integrative approach in exploration and suppression of cardiac amyloidosis. We propose to develop the first Drosophila model to investigate the cardiac defects associated with the accumulation of Alzheimer's and Huntington's disease-causing amyloid. Using the UAS-Gal4 expression system, we will express UAS-polyglutamine (for Huntington's) and UAS-A242 peptides (for Alzheimer's) in the Drosophila heart. We will examine the resulting cardiac defects at the physiological and cell biological levels. Furthermore, we will explore how expression of amyloid in the cardiac muscle afects expression of autophagy and other stress markers. We then plan to use genetic and pharmacological approaches to suppress cardiac amyloidosis. Genetic suppression of amyloids-induced cardiomyopathy will be attempted by over-expression of chaperones to reduce global protein unfolding or superoxide dismutase to ameliorate oxidative stress. We will also explore the effects of pharmacological agents such as chaperone inducers or antioxidants to ameliorate cardiac defects associated with amyloid accumulation. Our proposed study organism, Drosophila, with its high degree of gene conservation to the human genome and many techniques to manipulate its gene expression, will be an excellent model for exploring the mechanism of cardiac failure in Alzheimer's and Huntington's disease patients and may prove useful for developing therapies for human disease. Ultimately, once established, this model can be used for exploring genesis and suppression of cardiac amyloidosis linked with other amyloid precursor proteins. This proposal thus has broad applications and applies to cardiac, Alzheimer's and Huntington's diseases. All three diseases are devastating and the outcomes of this study may provide vital clues for their genesis. PUBLIC HEALTH RELEVANCE: Both Alzheimer's and Huntington's diseases are major risk factors for cardiac failure; the proposed study uses the model organism Drosophila melanogater for the first time to explore amyloid-induced cardiac dysfunction in these two major neurodegenerative diseases. We will use transgenic and pharmacological approaches for the suppression of the induced cardiac amyloidosis. This study is crucial for understanding the mechanism of cardiac failure in two major neuropathies and once established, this Drosophila model can be used to explore amyloid-induced cardiac failure associated with other amyloid precursor proteins.