Octyl gallate (OG) and Promotion of non-amyloidogenic processing of APP

描述（由申请人提供）： 近年来，对抗淀粉样前体蛋白（APP）裂解成A肽和由此产生的脑淀粉样变性（AD的关键病理特征）的治疗已成为主要焦点。主要目标是......然后呢？分泌酶，这两种蛋白酶分别在A肽的氨基和羧基末端切割APP，因此负责A肽的生成。另一种替代策略，即激活分泌酶，几乎没有研究。β-分泌酶在A β肽结构域内切割APP并阻止其生成，从而促进APP蛋白水解的非淀粉样蛋白生成途径。β-分泌酶激活也产生puereticneuroprotective sAPP-β。此外，以前的研究表明，增强激活的ADAM 10，一个主要的候选<$-分泌酶，减少了A <$代和预防认知障碍的小鼠模型的AD。我们先前的研究结果表明，EGCG通过体外激活ADAM 10促进非淀粉样蛋白生成APP蛋白水解，同样，在体内预防淀粉样蛋白病变。最近，我们发现，表没食子儿茶素没食子酸酯功能通过雌激素受体介导的激活ADAM 10在促进非淀粉样蛋白的加工APP。进一步这些事件与这些酚类化合物的没食子酸酯基团的存在呈正相关。 此外，我们已经表明，与EGCG相比，没食子酸辛酯（OG）对促进APP的分泌酶裂解具有显著的深远影响，从而限制了表达人野生型APP的神经元样N2 a细胞中的A？产生。最近，我们发现外源性人重组sAPP-<$蛋白通过与培养细胞中的主要<$-分泌酶候选物BACE 1特异性相互作用来促进非淀粉样蛋白生成APP的蛋白水解加工。sAPP-<$与BACE 1的这种相互作用抑制了其随后对全长APP的切割，从而进一步减少了A <$的产生。拟议研究的目标是定义OG中的这种非淀粉样蛋白生成机制，并确定潜在的分子药物靶点，这对于制定新的有效治疗AD至关重要。 在这个提议中，我们假设ADAM 10激活化合物，没食子酸辛酯（OG）从各种植物单宁的没食子酸产生，将增加APP的非淀粉样蛋白/α-分泌酶蛋白水解，并减少AD转基因小鼠模型中的脑淀粉样变性。我们希望明确定义这种非淀粉样蛋白的APP加工机制促进OG，并因此，确定潜在的分子药物靶点，这是必不可少的，制定新的，有效的治疗AD。本工作将通过以下目的的研究来完成：（I）研究雌激素受体（ER）信号传导在OG促进的抗淀粉样蛋白生成APP <$-分泌酶蛋白水解中的作用;表征sAPP-<$介导的OG诱导的抗淀粉样蛋白生成APP加工;（III）在体内评价没食子酸辛酯（OG）对 促进抗淀粉样蛋白生成APP分泌酶蛋白水解。在这些实验的最后，这些研究将提供的分子基础，为未来开发的OG作为新的和药物安全的药物用于阿尔茨海默病的预防/治疗。

DESCRIPTION (provided by applicant): Therapies opposing cleavage of amyloid precursor protein (APP) into A¿ peptides and resultant cerebral amyloidosis, a key pathological feature of AD, have become a primary focus in recent years. The main targets have been ¿- and ?-secretase, the two proteases that cleave APP at the amino and carboxyl-terminus of the A¿ peptide, respectively and, hence, are responsible for A¿ peptide generation. An alternative strategy, the activation of ¿-secretase, has scarcely been investigated. ¿-secretase cleaves APP within the A¿ peptide domain and precludes its generation, thereby promoting the non-amyloidogenic pathway of APP proteolysis. ¿-secretase activation also generates the putatively neuroprotective sAPP-¿. In addition, previous studies have shown that enhanced activation of ADAM10, a primary candidate ¿-secretase, has reduced A¿ generation and prevented cognitive impairment in a mouse model of AD. Our previous findings suggest that EGCG promotes non-amyloidogenic APP proteolysis by in vitro activation of ADAM10 and, similarly, prevent ¿-amyloid pathology in vivo. Recently, we found that EGCG functions through an estrogen receptor-mediated activation of ADAM10 in the promotion of non-amyloidogenic processing of APP. Further these events are positively correlated with presence of the gallate group of these phenolic compounds. Furthermore, we have shown that octyl gallate (OG) has a significantly profound effect on promoting ¿-secretase cleavage of APP thus limiting A¿ production in neuron-like N2a cells expressing human wild-type APP compared to EGCG. Most recently, we found that exogenous human recombinant sAPP-¿ protein promotes non-amyloidogenic APP proteolytic processing through specifically interacting with BACE1, a primary ¿-secretase candidate, in cultured cells. This interaction of sAPP-¿ with BACE1 inhibited its subsequent cleavage of full-length APP and resultant further decreased A¿ generation. The goal of the proposed research is to define this non-amyloidogenic mechanism in OG and identify potential molecular drug targets, which are essential for formulating novel, effective treatments against AD. In this proposal we hypothesize that ADAM10 activating compound, octyl gallate (OG) produced from the gallic acid of various plant tannins, will increase non-amyloidogenic/alpha-secretase proteolysis of APP, and reduce cerebral amyloidosis in a transgenic mouse model of AD. We expect to clearly define this non-amyloidogenic APP processing mechanism promoted by OG, and, consequently, identify potential molecular drug targets, which are essential for formulating novel, effective treatments against AD. This work will be completed by investigation of the following aims: (I) Investigate the role of estrogen receptor (ER) signaling in OG-promoted anti-amyloidogenic APP ¿-secretase proteolysis; Characterize sAPP-¿ mediation of OG-induced anti-amyloidogenic APP processing; (III) In vivo evaluation of the effect of octyl gallate (OG) for the promotion of anti-amyloidogenic APP ¿-secretase proteolysis. At the end of these experiments, these studies will provide the molecular basis for the future development of OG as novel and pharmacologically safe agents for Alzheimer's disease prevention/treatment.