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。如果不采取新的和重大的预防或治疗措施，这一日益严重的问题将在财政和精神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AD的进展有关。这主要是基于观察到AD脑中各种巯基蛋白酶的“激活”状态增加。然而，其他数据表明，巯基蛋白酶不完全具有蛋白水解活性，巯基蛋白酶的抑制更可能导致AD病理学。因此，在阿尔茨海默病中观察到的巯基蛋白酶的活化和它们的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1”和巯基蛋白酶“活性”的矛盾发现需要解决，以便向前推进并确定巯基蛋白酶在tau和Abeta积累以及阿尔茨海默病期间细胞死亡/功能障碍中的作用。为了解决这一差距，我们的知识，我们将测试的假设，“激活”巯基蛋白酶在其活性位点的半胱氨酸氧化抑制特定的氧化剂在阿尔茨海默病的海马。目标1：确定阿尔茨海默病大脑中巯基依赖性蛋白酶的活性，与年龄匹配的对照组相比，在脆弱的海马和非脆弱的小脑中。基于我们最近发表的工作，我们将表明，巯基蛋白酶的活性，包括钙依赖性巯基蛋白酶的活性，氧化抑制AD脑海马相比，年龄匹配的控制。由于AD变性是进行性的，我们还将使用来自阿尔茨海默病各个阶段的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AD大鼠海马巯基蛋白酶氧化的氧化剂。这些研究将确定氧化的程度和负责AD海马体中单个巯基依赖性蛋白酶内活性位点半胱氨酸氧化的氧化剂。这一假说挑战了现有的范式，表明硫醇蛋白酶活性在阿尔茨海默氏病是减少（而不是增加），由于氧化的活性位点。拟议的研究将对未来的治疗方法产生影响，包括抗氧化剂或蛋白酶抑制剂策略治疗或预防阿尔茨海默病。

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.