Model for SorCS1-mediated Diabetes with Dementia

SorCS1 介导的糖尿病伴痴呆模型

• 批准号: 8295466
• 负责人: SAMUEL E. GANDY
• 金额: $ 37.08万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-15 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8295466
• 关键词: Aging; Alzheimer' s Disease; Alzheimer' s disease risk; Amyloid beta-Protein; Behavior; Brain; Characteristics; Complex; Cultured Cells; Data; Dementia; Diabetes Mellitus; Disease; Family; Female; Functional disorder; Gender; Gene Transfer; Generations; Genetic; Genetic Polymorphism; Human; Insulin; Insulin Resistance; Learning; Link; Mediating; Metabolic; Metabolism; Modeling; Molecular; Mus; Mutation; Non-Insulin-Dependent Diabetes Mellitus; Patients; Peptides; Phenotype; Phosphorylation; Protein Precursors; Proteins; Risk; Role; Serine; Structure; Tertiary Protein Structure; Testing; Transgenic Mice; Vacuolar Protein Sorting; Vertebral column; Viral Genes; Work; genetic association; genetic linkage; glucose metabolism; glucose tolerance; hippocampal morphometry; hypercholesterolemia; insulin tolerance; overexpression; protein complex; protein metabolism; protein transport; sexual dimorphism; sortilin; trafficking

DESCRIPTION (provided by applicant): Type 2 diabetes mellitus (T2D or T2DM) increases the risk for Alzheimer's disease (AD), and SORCS1 is genetically linked to both T2D and AD. We have undertaken a study of the possible role(s) for SorCS1 in metabolism of the Alzheimer's amyloid-? (A?)?precursor protein (APP), in order to define the molecular mechanisms underlying this coordinate genetic linkage to both diseases. Overexpression of SorCS1cb-myc in cultured cells caused a reduction (p=0.002) in?A? generation (Lane et al., 2010). Endogenous murine A?40 and A?42 levels were increased (A?40, p=0.044; A?42, p=0.007) in the brains of female Sorcs1 hypomorphic mice, possibly paralleling the sexual dimorphism that is characteristic of the genetic associations of SORCS1 with AD and DM. Since SorL1, another AD-linked Vps10-domain protein, directly interacts with Vps35 to modulate APP metabolism, we investigated the possibility that SorCS1cb-myc might interact with APP, SorL1, and/or Vps35. We readily recovered SorCS1:APP, SorCS1:SorL1, and SorCS1:Vps35 complexes from nontransgenic mouse brain. Notably, total Vps35 protein levels were decreased by 49% (p=0.009) and total SorL1 protein levels were decreased by 29% (p=0.003) in the brains of female Sorcs1-/- mice. We hypothesize that dysfunction of SorCS1 may contribute to both the APP/A??disturbance underlying AD and the insulin/glucose metabolism disturbance underlying DM. In order to test this hypothesis further, we propose the following specific aims: Specific Aim 1. To evaluate the importance of SorCS1 protein interaction motifs and SorCS1/SorL1/APP complex formation on APP metabolism by: (a) Characterizing APP metabolism in cultured cells overexpressing SorCS1; (b) Testing the effects of mutations of protein-protein interacting motifs in the cytoplasmic and ectodomains of SorCS1 on both the formation of tripartite SorCS1/SorL1/APP complexes and APP metabolism; (c) Testing the effect of a putative pathogenic SorCS1 polymorphism on both the formation of tripartite SorCS1/SorL1/APP complexes and APP metabolism; (d) Confirming the importance of functional domains identified in Aim 1aii and 1aiii by viral gene transfer into primary cultures. Specific Aim 2. To employ Sorcs1 hypomorphic and plaque forming human Swedish APP/PS bigenic mice crossed with Sorcs1 hypomorphic mice for characterization of: (i) endogenous APP metabolism; (ii) hippocampal morphometry, dendritic arborization, and spine structure; (c) learning behavior. Aging (3 mo, 6 mo, 12 mo) effects will also be studied. Specific Aim 3. To perform standard glucose and insulin tolerance tests and metabolic profile phenotyping of Sorcs1-/- mice and plaque-forming" human Swedish APP/PS co-transgenic mice crossed with Sorcs1 -/- mice. PUBLIC HEALTH RELEVANCE: Type 2 diabetes mellitus (T2DM) increases the risk for Alzheimer's disease (AD). Both diseases are highly complex, and several mechanisms have been proposed for this association, including hypercholesterolemia, vasculopathic factors, and insulin resistance, among others. We sought and identified a genetic factor, SORCS1, that is an excellent candidate for modulation of a coordinated risk for both diseases, and we now propose to work out mechanistic details for how SorCS1 controls risk for AD and T2DM.

描述（由申请人提供）：2型糖尿病（T2 D或T2 DM）增加阿尔茨海默病（AD）的风险，SORCS 1与T2 D和AD均存在遗传关联。我们已经进行了一项研究，可能的作用（S）SorCS 1在阿尔茨海默氏症的淀粉样蛋白的代谢？（A？）？前体蛋白（APP），以确定这两种疾病的协调遗传连锁的分子机制。SorCS 1cb-myc在培养细胞中的过表达引起了细胞凋亡的减少（p=0.002）。一个？代（Lane等人，2010年）。内源性小鼠A？40和A？42个水平增加（A？40，p=0.044; A？42，p=0.007），可能平行的性别二型性，这是SORCS 1与AD和DM的遗传关联的特征。由于SorL 1，另一个AD连接的Vps 10结构域蛋白，直接与Vps 35相互作用，调节APP代谢，我们研究了SorCS 1cb-myc可能与APP，SorL 1，和/或Vps 35相互作用的可能性。我们很容易从非转基因小鼠脑中回收SorCS 1：APP、SorCS 1：SorL 1和SorCS 1：Vps 35复合物。值得注意的是，在雌性Sorcs 1-/-小鼠的大脑中，总Vps 35蛋白水平降低了49%（p=0.009），总SorL 1蛋白水平降低了29%（p=0.003）。我们推测SorCS 1的功能障碍可能与APP/A？AD基础的胰岛素/葡萄糖代谢紊乱和DM基础的胰岛素/葡萄糖代谢紊乱。为了进一步验证这一假设，我们提出了以下具体目标：具体目标1。通过以下方法评价SorCS 1蛋白相互作用基序和SorCS 1/SorL 1/APP复合物形成对APP代谢的重要性：（a）表征过表达SorCS 1的培养细胞中的APP代谢;（B）测试SorCS 1胞质和胞外域中蛋白-蛋白相互作用基序突变对三重SorCS 1/SorL 1/APP复合物形成和APP代谢的影响;（c）测试推定的致病性SorCS 1多态性对三重SorCS 1/SorL 1/APP复合物的形成和APP代谢的影响;（d）通过将病毒基因转移到原代培养物中来证实在Aim 1aii和1aiii中鉴定的功能结构域的重要性。具体目标2。采用Sorcs 1亚纯型和斑块形成人瑞典APP/PS双基因小鼠与Sorcs 1亚纯型小鼠杂交，以表征：（i）内源性APP代谢;（ii）海马形态学、树突状分支和棘结构;（c）学习行为。还将研究老化（3个月、6个月、12个月）的影响。具体目标3。对Sorcs 1-/-小鼠和与Sorcs 1-/-小鼠杂交的空斑形成”人Swedish APP/PS共转基因小鼠进行标准葡萄糖和胰岛素耐量试验以及代谢谱表型分析。 公共卫生相关性：2型糖尿病（T2 DM）会增加阿尔茨海默病（AD）的风险。这两种疾病都是高度复杂的，并且已经提出了这种关联的几种机制，包括高胆固醇血症、血管病变因素和胰岛素抵抗等。我们寻找并鉴定了一种遗传因子SORCS 1，它是调节这两种疾病协调风险的一个很好的候选者，我们现在建议研究SorCS 1如何控制AD和T2 DM风险的机制细节。