Oxidation of cysteine-proteases in Alzheimer's Disease

描述（由申请人提供）：阿尔茨海默病是痴呆症的最常见原因，影响全球近1800万人，预计在未来20年内将翻一番。如果没有新的和重要的预防或治疗措施，这一日益严重的问题将在经济和情感压力方面给社会带来沉重负担。先前的研究表明，巯基蛋白酶的过度激活与阿尔茨海默病的进展有关。这主要是基于对阿尔茨海默病大脑中各种巯基蛋白酶“激活”状态增加的观察。然而，其他数据表明，巯基蛋白酶并不具有完全的蛋白水解活性，巯基蛋白酶的抑制更有可能导致AD病理。因此，在阿尔茨海默病中观察到的巯基蛋白酶的活化与其蛋白水解活性之间存在重要的差异。这些关于巯基蛋白酶“激活”和巯基蛋白酶“活性”的相互矛盾的发现需要得到解决，以便进一步确定巯基蛋白酶在阿尔茨海默病期间tau和Abeta积累以及细胞死亡/功能障碍中的作用。为了解决我们知识上的这一空白，我们将测试“活化”的硫醇蛋白酶在其活性位点半胱氨酸被阿尔茨海默病海马中的特定氧化剂氧化抑制的假设。目的1：确定阿尔茨海默病大脑中硫醇依赖性蛋白酶的活性，与易感海马和非易感小脑中的年龄匹配对照进行比较。根据我们最近发表的工作，我们将证明，与年龄匹配的对照组相比，阿尔茨海默病大脑海马中的硫醇蛋白酶活性，包括钙依赖性硫醇蛋白酶活性，被氧化抑制。由于阿尔茨海默病退行性变是进行性的，我们还将使用阿尔茨海默病不同阶段的大脑样本来确定硫醇蛋白酶氧化在疾病进展中的程度。目的2：确定阿尔茨海默病脑海马中硫醇蛋白酶氧化的氧化剂。这些研究将确定阿尔茨海默病海马中单个硫醇依赖蛋白酶活性位点半胱氨酸氧化的程度和氧化剂。这一假说挑战了现有的范式，认为巯基蛋白酶在阿尔茨海默病中的活性由于活性位点的氧化而降低（而不是增加）。该研究将对未来治疗方法产生影响，包括抗氧化剂或蛋白酶抑制剂治疗或预防阿尔茨海默病的策略。

DESCRIPTION (provided by applicant): Alzheimer's disease is the most common cause of dementia affecting nearly 18 million people worldwide and projected to double over the next 20 years. Without new and significant preventative or curative measures this growing problem will place a substantial burden on society in terms of both financial and emotional strains. Previous research has implicated over activation of thiol-proteases in AD progression. This is based primarily on the observation of an increased 'activation' state of various thiol-proteases in AD brain. However, other data suggest that thiol-proteases are not fully proteolytically active and that inhibition of thiol-proteases is more likely to contribute to AD pathology. Thus, there is an important discrepancy between the observed activation of thiol-proteases and their proteolytic activity in Alzheimer's disease. These contradictory findings regarding thiol-protease 'activation1 and thiol-protease 'activity' need to be resolved in order to move forward and determine the role of thiol-proteases in tau and Abeta accumulation as well as cell death/ dysfunction during Alzheimer's disease. To address this gap in our knowledge we will test the hypothesis that the 'activated' thiol-proteases are oxidatively inhibited at their active-site cysteines by specific oxidants in the hippocampus of Alzheimer's disease. Aim 1: Determine the activity of thiol-dependent proteases in Alzheimer's disease brain compared to age-matched controls within the vulnerable hippocampus and the non-vulnerable cerebellum. Based on our recently published work, we will show that thiol-protease activity, including calcium-dependent thiol-protease activity, is oxidatively inhibited in the hippocampus of AD brain compared to age-matched controls. Because AD degeneration is progressive, we will also determine the extent of thiol-protease oxidation over the progression of the disease using brain samples from various stages of Alzheimer's disease. Aim 2: Determine the oxidants responsible for thiol-protease oxidation in the hippocampus of AD brain. These studies will determine the extent of oxidation and the oxidants responsible for oxidation of active-site cysteines within individual thiol- dependent proteases in AD hippocampus. This hypothesis challenges an existing paradigm by suggesting thiol-protease activity in Alzheimer's disease is decreased (rather than increased) due to oxidation of the active site. The proposed research will have impact on future therapeutics involving anti-oxidant or protease inhibitor strategies in the treatment or prevention of Alzheimer's disease.