Characterization of Alzheimer's Mutations in ADAM10.

ADAM10 中阿尔茨海默病突变的表征。

• 批准号: 8438141
• 负责人: RUDOLPH Emile TANZI
• 金额: $ 34.59万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-30 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8438141
• 关键词: Age of Onset; Alzheimer' s Disease; Amyloid; Amyloid beta-Protein Precursor; Animal Model; Attenuated; Biochemical; Biological Assay; Biotinylation; Brain; Catalytic Domain; Cell membrane; Cerebrum; Clinical; Cognitive; Collection; Data; Density Gradient Centrifugation; Development; Disease; Dominant-Negative Mutation; Electrophysiology (science); Etiology; Exhibits; Family; Foundations; Gene Expression; Genes; Genetic; Genotype; In Vitro; Knock-in Mouse; Late Onset Alzheimer Disease; Linkage Disequilibrium; Long-Term Potentiation; Memory; Metalloproteases; Missense Mutation; Molecular; Molecular Chaperones; Mus; Mutation; National Institute of Mental Health; Pathogenesis; Pathogenicity; Peptide Hydrolases; Phenotype; Play; Prevention; Production; Property; Proteins; Regulation; Reporting; Role; Sampling; Senile Plaques; Single Nucleotide Polymorphism; Staining method; Stains; Structure; Surface; System; Testing; Tg2576; Transgenic Mice; Transgenic Organisms; Validation; Variant; Yeasts; amyloid precursor protein processing; base; cognitive function; disease phenotype; enzyme activity; familial Alzheimer disease; genome wide association study; in vivo; mouse model; mutant; neuropathology; novel; overexpression; proband; protein folding; secretase; segregation; trafficking

DESCRIPTION (provided by applicant): Abundant clinical, genetic, and biochemical data support the hypothesis that abnormal processing of the amyloid precursor protein (APP) and the cerebral accumulation of its metabolite, A¿, play key roles in the etiology and pathogenesis of Alzheimer's disease (AD). A¿ is generated via serial cleavage of APP by ¿- and ¿- secretase. In contrast, cleavage of APP by ¿-secretase precludes A¿ production; the major ¿-secretase in the brain is ADAM10. We recently reported two rare missense mutations in ADAM10 that strongly co- segregates with late-onset AD (LOAD). Both are prodomain mutations that were found in 7 of 1000 NIMH and NIA LOAD families tested (average age of onset, ~70 years). We have also previously reported that both mutations significantly attenuated ¿-secretase activity and elevated A¿ levels in vitro. To further validate and expand upon these novel findings, we propose to 1. Search for additional novel familial LOAD mutations in ADAM10; 2. Validate the pathogenicity of these two missense mutations in vivo; and 3. Determine the molecular mechanism by which these two mutations impair ¿-secretase activity. For Aim 1, we will search for additional novel familial LOAD mutations in ADAM10, through targeted re-sequencing (and genotyping) of 2454 additional AD families (N=6516 subjects) from the NIMH and NIA AD family collections. Our family-based GWAS on >900 NIMH and NIA AD families suggest the existence of additional AD-associated SNPs in ADAM10. With regard to Aim 2, we will attempt to validate the pathogenicity of these two mutations in vivo in transgenic mice (already generated) overexpressing either wild-type (WT) or mutant (Q170H, R181G, artificial dominant-negative) forms of ADAM10. These mice have already been crossed with Tg2576 (APPswe) AD mice so that we can also test for effects of these mutations on neuropathological and cognitive phenotypes of AD. Our preliminary in vivo results reveal that the ADAM10 prodomain mutations attenuate non-amyloidogenic processing of APP, and that senile plaque counts and A¿ levels were significantly increased in the brains of APPswe/ADAM10 double transgenic mice expressing mutant forms of ADAM10, as compared to those expressing WT forms. Moreover, to test the impact of the prodomain mutations under more physiologically relevant conditions, we have added a plan to generate and characterize ADAM10 mutant knock-in mice. Finally, in Aim 3, we will investigate the molecular mechanism by which the prodomain mutations down- regulate ADAM10 ¿-secretase activity. Briefly, we will test for effects of these mutations on three prodomain functions: regulation of enzyme activity, intracellular trafficking, and intramolecular chaperoning. At the completion of this project, we hope to provide genetic, biochemical, and mechanistic evidence validating the pathogenicity of late-onset familial AD mutations in ADAM10. Moreover, the data emerging from the proposed study would serve as a firm foundation for the discovery and development of new therapies targeting ADAM10 for the treatment and prevention of this devastating disease. PUBLIC HEALTH RELEVANCE: We will attempt to establish in vivo validation for the pathogenicity and to elucidate the molecular mechanism of two ADAM10 prodomain mutations, which we have already confirmed in several late-onset Alzheimer's disease (AD) families. We will also search for additional AD mutations in the ADAM10 gene.

描述(申请人提供)：大量的临床、遗传和生化数据支持这一假设，即淀粉样前体蛋白(APP)的异常加工及其代谢物A？在阿尔茨海默病(AD)的病因和发病机制中发挥关键作用。A是通过分泌酶对APP的连续切割而产生的。相反，分泌酶对APP的切割排除了A的产生；大脑中主要的分泌酶是ADAM10。我们最近报道了ADAM10中两个罕见的错义突变，它们与晚发性AD(LOAD)强烈共分离。两者都是前结构域突变，在所测试的1000个NIMH和NIA负载家族中(平均发病年龄~70岁)中有7个被发现。我们之前也报道过，在体外，这两个突变都显著降低了分泌酶的活性，提高了A‘的水平。为了进一步验证和扩展这些新的发现，我们建议：1.寻找ADAM10中其他新的家族负荷突变；2.在体内验证这两个错义突变的致病性；以及3.确定这两个突变削弱分泌酶活性的分子机制。对于目标1，我们将通过对NIMH和NIA AD家族集合中的2454个AD家族(N=6516名受试者)进行有针对性的重新测序(和基因分型)，寻找ADAM10中其他新的家族负载突变。我们基于家族的Gwas on&gt；900 NIMH和NIA AD家族提示ADAM10中存在更多与AD相关的SNPs。关于目标2，我们将尝试在过量表达野生型(WT)或突变(Q170H，R181G，人工显性阴性)形式的ADAM10的转基因小鼠(已产生)中验证这两种突变的体内致病性。这些小鼠已经与Tg2576(APPswe)AD小鼠杂交，因此我们还可以测试这些突变对AD的神经病理和认知表型的影响。我们在体内的初步结果显示，ADAM10前结构域的突变减弱了APP的非淀粉样变性过程，与表达WT形式的小鼠相比，表达ADAM10突变形式的APPswe/ADAM10双转基因小鼠的脑中衰老斑块计数和A？水平显著增加。此外，为了测试前结构域突变在更具生理相关性的条件下的影响，我们增加了一项计划，以产生和表征ADAM10突变敲入小鼠。最后，在目标3中，我们将研究前结构域突变下调ADAM10分泌酶活性的分子机制。简而言之，我们将测试这些突变对三个 原结构域功能：酶活性的调节、细胞内转运和分子内伴侣作用。在这个项目完成后，我们希望提供遗传学、生化和机械学证据来验证ADAM10中晚发型家族性AD突变的致病性。此外，拟议研究中产生的数据将为发现和开发针对ADAM10的治疗和预防这种毁灭性疾病的新疗法奠定坚实的基础。 公共卫生相关性：我们将尝试建立体内致病性验证，并阐明两个ADAM10原结构域突变的分子机制，我们已经在几个晚发性阿尔茨海默病(AD)家族中证实了这一点。我们还将寻找ADAM10基因中更多的AD突变。