Aminopeptidases for Neurotoxic Pyroglutamate Beta-Amyloid of Alzheimers Disease

描述(由申请人提供)：N-末端截断焦谷氨酸(PGlu)修饰形式的β-淀粉样蛋白(A？)，pGluA？(3-40/42)(称为pGluA？)，在阿尔茨海默病中显示出高度的神经毒性、神经变性和记忆丧失。值得注意的是，pGluA？在AD大脑中含量丰富，并且存在于高于A？的水平(1-40/42)。PGluA？加速A？和pGluA？寡聚体的形成，从而导致AD的神经毒性细胞死亡和记忆障碍。PGluA？(3-40/42)肽以N-末端谷氨酸开始，它是A？(1-40/42)的第三个氨基酸。PGluA？多肽是由A？(1-40/42)通过氨基肽酶去除N-末端天冬氨酸和丙氨酸残基，然后N-末端谷氨酸环化而产生的。产生pGluA‘肽所需的氨基肽酶还没有被阐明。因此，该项目的目标将是确定产生神经毒性pGluA？的氨基肽酶机制，该机制参与AD的发展。这一结果可以为阿尔茨海默病提供新的蛋白酶靶点。这个项目的假设是，天冬氨酸氨基肽酶和丙氨酸氨基肽酶产生A？(3-40/42)，它被谷氨酰环酶(QC)转化为pGluA？(3-40/42)。这一假说得到了我们的初步数据的支持，这些数据表明，在含有pGluA？(3-40/42)和A？(1-40/42)的分泌囊泡中存在天冬氨酸和丙氨酸氨基肽酶活性。这一假说将在三个特定的目标下进行评估，以(1)鉴定产生A的分泌小泡中的天冬氨酸和丙氨酸氨基肽酶，这些酶从A？中去除N-末端天冬氨酸和丙氨酸残基(1-40/42)，(2)通过基因沉默和表达来评估识别的氨基肽酶在产生pGluA方面的作用(3-40/42)，以及(3)评价这些氨基肽酶活性的抑制剂以减少pGluA的产生(3-40/42)。该项目将确定产生神经毒性pGluA多肽的新的氨基肽酶机制。结果还将产生这些氨基肽酶的候选抑制剂，用于未来研究阿尔茨海默病中氨基肽酶的调节。

DESCRIPTION (provided by applicant): The N-terminal truncated pyroglutamate (pGlu) modified forms of beta-amyloid (A ¿), pGluA ¿ (3-40/42) (referred to as pGluA ¿), display high neurotoxicity, neurodegeneration and memory loss in Alzheimer's disease. Notably, pGluA ¿ is abundant in AD brains and is present at levels greater than A¿ (1-40/42). The pGluA ¿ accelerates formation of A¿ and pGluA ¿ oligomers that cause neurotoxic cell death and memory deficits in AD. The pGluA ¿ (3-40/42) peptides begin with N-terminal glutamate, the third amino acid of A¿ (1-40/42). pGluA¿ peptides are generated from A ¿ (1-40/42) by aminopeptidases that remove the N-terminal aspartate and alanine residues, followed by cyclization of the N-terminal glutamate. The aminopeptidases required to generate pGluA¿ peptides have not yet been elucidated. Therefore, the goal of this project will be to identify the aminopeptidase mechanisms responsible for generating neurotoxic pGluA¿ that participates with A ¿ in development of AD. Results can provide novel protease targets for Alzheimer's disease. The hypothesis of this project is that the aspartate aminopeptidase and alanine aminopeptidase enzymes generate A ¿ (3-40/42) which is converted to pGluA¿(3-40/42) by glutaminyl cyclase (QC). This hypothesis is supported by our preliminary data demonstrating the presence of aspartate and alanine aminopeptidase activities in secretory vesicles that contain pGluA¿ (3-40/42) and A¿ (1-40/42). This hypothesis will be assessed in three specific aims to (1) identify aspartate and alanine aminopeptidases in A ¿ -producing secretory vesicles that remove the N-terminal Asp and Ala residues from A ¿ (1-40/42), (2) evaluate identified aminopeptidases by gene silencing and expression for their roles in producing pGluA¿ (3-40/42), and (3) evaluate inhibitors of these aminopeptidase activities to reduce production of pGluA¿ (3- 40/42). This project will identify new aminopeptidase mechanisms for producing neurotoxic pGluA¿ peptides. Results will also yield candidate inhibitors of these aminopeptidases for future investigation of aminopeptidase regulation in Alzheimer's disease.