Novel mechanisms for Alzheimer disease prevention and or treatment

问题：衰老是阿尔茨海默病(AD)最重要的风险因素，它代表着 在我国导致痴呆症的最常见原因。这种疾病目前还没有可用的治疗方法 治疗，在我们日益老龄化的退伍军人群体中正变得越来越普遍。 初步数据：自噬是细胞降解机制的重要组成部分。这很有帮助 处理在分泌途径和胞浆中形成的大的有毒蛋白质聚集体。 自噬功能障碍和蛋白平衡紊乱导致许多慢性疾病的进展 疾病。此外，许多慢性退行性疾病的特点是异常堆积。 有毒蛋白质聚集体。令人信服的数据表明，提高自噬水平可能有益于 以有毒蛋白聚集体积累增加为特征的小鼠疾病模型，包括 广告。因此，改善正常的蛋白抑制机制是生物医学研究的一个积极目标。Nε- 赖氨酸乙酰化最初被认为只发生在细胞质和细胞核中。然而，在2007年，我们 发现内质网(ER)也能够乙酰化新合成的多肽。 从那时起，我们已经成功地确定了负责ER-乙酰化的整个生化机制 并制作了相应的动物模型。该机器包括AT-1，它将乙酰辅酶A从 胞浆到内质网管腔，以及ATase1/ATase2，这两种乙酰基转移酶执行酶 ER管腔内的反应。我们发现ER乙酰化机制维持内环境平衡 ER的两个基本且密切相关的功能的平衡：(一)正确折叠的“正”选择 新生多肽和(Ii)对自噬/网噬的严格调控。小鼠的乙酰-内流减少 CoA进入内质网(AT-1S113R/+)显示过度诱导自噬和阻断分泌途径 而内流增加的小鼠(AT-1Tg和AT-1stg)表现出更高的分泌效率 途径和正常的网状吞噬障碍。在这两种情况下，缺乏体内平衡会导致严重的 表型。与这一提议相关的还有一个事实，即一个功能失调的ER乙酰化机制具有 与衰老和阿尔茨海默病有关。一直以来，AT-1单倍体不足或生化抑制 ATASS能挽救小鼠的AD样表型。 假设：我们的一般假设是内质网乙酰化机制确保蛋白质 动态平衡。放松对这种串扰的管制既会影响衰老，也会影响AD。 研究设计：特定目标1将确定新的基于结构的ATase1和ATase2抑制剂以 预防AD。这一目标将利用我们收集的关于 ATase和我们最近发现的新的基于结构的抑制剂。相关结构 这些新药的生物化学、体外和体外分析以及制剂前/制剂开发 大院已经完工了。他们现在将在AD的两个小鼠模型上进行测试。这一目标 还将利用我们实验室最近培育的ATase1-/-和ATase2-/-小鼠来确定 仅靶向一种ATase是否足以挽救小鼠的AD神经病理。具体目标2 将确定为内质网蛋白恒定功能提供特异性的分子机制(S) 乙酰化机。在这一目标下，我们报告了一种新的基于内质网的乙酰转移酶的鉴定 这似乎在调节内质网下游的自噬/网状吞噬中发挥了重要作用 乙酰化机。这个目标是高度机械化的，包括结构生物化学、 分子生物学和体外/体外分析。

PROBLEM: Aging is the most important risk factor for Alzheimer's disease (AD), which represents the most common cause of dementia in our country. The disease, for which there is no currently available treatment, is becoming increasingly prevalent among our aging veteran population. PRELIMINARY DATA: Autophagy is an essential component of the cell degrading machinery. It helps dispose of large toxic protein aggregates that form within the secretory pathway and in the cytosol. Malfunction of autophagy and disruption of proteostasis contributes to the progression of many chronic diseases. In addition, many chronic degenerative diseases are characterized by the aberrant accumulation of toxic protein aggregates. Compelling data indicate that increased levels of autophagy can be beneficial in mouse models of diseases characterized by increased accumulation of toxic protein aggregates, including AD. As such, improving normal proteostatic mechanisms is an active target for biomedical research. Nε- lysine acetylation was initially thought to occur only in the cytoplasm and nucleus. However, in 2007 we discovered that the endoplasmic reticulum (ER) is also able to acetylate newly-synthesized polypeptides. Since then, we have successfully identified the entire biochemical machinery responsible for ER-acetylation and generated relevant animal models. The machinery includes AT-1, which translocates acetyl-CoA from the cytosol to the ER lumen, and ATase1/ATase2, two acetyltransferases that carry out the enzymatic reaction within the ER lumen. We discovered that the ER acetylation machinery maintains the homeostatic balance of two essential and intimately related functions of the ER: (i) “positive” selection of correctly folded nascent polypeptides and (ii) tight regulation of autophagy/reticulophagy. Mice with reduced influx of acetyl- CoA into the ER (AT-1S113R/+) display excessive induction of autophagy and a block of the secretory pathway while mice with increased influx (AT-1 Tg and AT-1 sTg) display increased efficiency of the secretory pathway and a block of normal reticulophagy. In both cases, lack of homeostatic balance leads to drastic phenotypes. Relevant to this proposal is also the fact that a dysfunctional ER acetylation machinery has been linked to aging and AD. Consistently, haploinsufficiency of AT-1 or biochemical inhibition of the ATases was able to rescue the AD-like phenotype in the mouse. HYPOTHESIS: Our general hypothesis is that the ER acetylation machinery ensures protein homeostasis. Deregulation of this cross-talk impacts both aging and AD. STUDY DESIGN: Specific Aim 1 will identify novel structure-based ATase1 and ATase2 inhibitors to prevent AD. This Aim will take advantage of new structural information that we have collected on the ATases and new structure-based inhibitors that we have recently identified. Relevant structural biochemistry, in vitro and ex vivo analysis, and pre-formulation/formulation development of these novel compounds have already been completed. They will now be tested in two mouse models of AD. This Aim will also take advantage of ATase1-/- and ATase2-/- mice, recently generated in our laboratory to determine whether targeting only one ATase is sufficient to rescue AD neuropathology in the mouse. Specific Aim 2 will identify the molecular mechanism(s) that provides specificity to the proteostatic functions of the ER acetylation machinery. Under this Aim we report the identification of a novel ER-based acetyltransferase that appears to play an important role in the regulation of autophagy/reticulophagy down-stream of the ER acetylation machinery. This Aim is highly mechanistic and includes a combination of structural biochemistry, molecular biology and in vitro/ex vivo analysis.