Synphilin-1 and obesity

描述（由申请人提供）：肥胖症是最常见的代谢性疾病，由摄入的热量超过持续需求引起。肥胖症患病率的增加导致肥胖症相关疾病如2型糖尿病和心血管疾病的发病率迅速加快。肥胖症的发病机制仍不完全清楚。在本申请中，我们提出研究突触亲蛋白-1在食物摄入和体重控制中的新作用。Synphilin-1是一种细胞质蛋白，与α-突触核蛋白和parkin相互作用，并在与蛋白质聚集相关的帕金森病发病机制中具有意义。通过研究突触亲蛋白-1转基因小鼠（SP1）的表型，我们有证据表明突触亲蛋白-1过表达显著增加体重，并且通过增加食物摄入来增加体重。我们发现，synphilin-1在参与能量平衡的下丘脑核团的神经元中高度表达，这表明synphilin-1可能通过调节下丘脑信号传导来影响能量平衡。我们的初步数据表明，synphilin-1可能会影响食物的摄入量和体重，通过增加食欲基因：下丘脑神经元中的NPY和AgRP的表达。近年来的研究表明，AMP激活激酶（AMPK）是一种中枢神经元能量传感器，在维持能量稳态中起着重要作用。我们的初步数据表明，人synphilin-1的表达增加AMPK磷酸化培养的N1 E-115细胞和PVN网站，并进一步表明，synphilin-1与AMPK相互作用，如所示的免疫共沉淀。因此，在这个建议中，我们将测试的假设，synphilin-1调节下丘脑摄食相关的基因表达和AMPK信号级联反应，导致暴食症和肥胖症。在目标1中，我们将描述食物摄入量，体重和下丘脑基因表达模式的变化，以应对过表达的synphilin-1。我们将通过测试对中枢和外周肽给药的反应并表征其味觉偏好，具体评估SP1小鼠中以摄食量增加为特征的摄食量增加的基础。在目标2中，我们将研究内源性下丘脑synphilin-1在代谢状态改变中的作用。在目标3中，我们将在体外细胞培养系统中测试突触亲蛋白-1改变AMPK信号级联及其相关细胞能量事件的假设。在目的4中，我们将使用过表达和siRNA敲低方法来测试突触亲蛋白-1激活下丘脑中的AMPK信号传导导致体内摄食过多和肥胖的假设。这些研究将深入了解synphilin-1诱导的暴食和肥胖的分子机制，将扩大我们对synphilin-1的生物学功能的了解，并可能为未来研究肥胖的发病机制提供一个独特的遗传肥胖模型。公共卫生相关性：我们拟从行为学、药理学和细胞生物学等方面探讨synphilin-1蛋白在调节摄食量和体重中的作用及其分子机制。这些研究将大大增加我们对synphilin-1生物学功能的理解，并将为肥胖和相关疾病的分子机制提供新的见解。

DESCRIPTION (provided by applicant): Obesity is the most common metabolic disease, resulting from the ingestion of calories in excess of ongoing requirements. Increased prevalence of obesity has resulted in rapidly accelerating rates of obesity related disorders such as type 2 diabetes and cardiovascular disease. The pathogenesis of obesity remains incompletely understood. In the current application, we propose to investigate a novel role for synphilin-1 in food intake and body weight control. Synphilin-1, a cytoplasmic protein, interacts with alpha-synuclein and parkin and has implications in Parkinson's disease pathogenesis related to protein aggregation. Through work examining the phenotype of a synphillin-1 transgenic mouse (SP1), we have evidence that synphilin-1 over- expression significantly increases body weight and does so through increasing food intake. We have found that synphilin-1 is highly expressed in neurons of hypothalamic nuclei involved in energy balance, suggesting that synphilin-1 may be affecting energy balance by modulating hypothalamic signaling. Our preliminary data suggest that synphilin-1 may affect food intake and body weight through increases in orexigenic genes: NPY and AgRP expression in hypothalamic neurons. Recently, studies have suggested that AMP-activated kinase (AMPK) is a central neuronal energy sensor that plays a major role in maintaining energy homeostasis. Our preliminary data showed that expression of human synphilin-1 increased AMPK phosphorylation in cultured N1E-115 cells and at the PVN site, and further showed that synphilin-1 interacted with AMPK as indicated by co-immunoprecipitation. Thus, in this proposal, we will test the hypothesis that synphilin-1 modulates hypothalamic feeding related gene expression and AMPK signaling cascades resulting in hyperphagia and obesity. In Aim 1, we will characterize changes in food intake, body weight and patterns of hypothalamic gene expression in responses to overexpression of synphilin-1. We will specifically assess the bases for the increased meal size that characterizes the hyperphagia in SP1 mice by testing responses to central and peripheral peptide administration and characterizing their taste preferences. In Aim 2, we will investigate the role of endogenous hypothalamic synphilin-1 in response to alterations in metabolic status. In Aim 3, we will test the hypothesis that synphilin-1 alters AMPK signaling cascades and its related cell energy events in an in vitro cell culture system. In Aim 4, we will test the hypothesis that synphilin-1 activates AMPK signaling in hypothalamus resulting in hyperphagia and obesity in vivo using overexpression and siRNA knockdown approaches. These studies will provide insight into the molecular mechanisms underlying synphilin-1-induced hyperphagia and obesity, will enlarge our knowledge of the biological functions of synphilin-1, and may provide a unique genetic obesity model for future studies of the pathogenesis of obesity. PUBLIC HEALTH RELEVANCE: We propose to investigate the role and the molecular mechanisms of synphilin-1 protein in regulating food intake and body weight using behavioral, pharmacological and cell biological approaches. These studies will greatly increase our understanding of the biological functions of synphilin-1 and will provide new insights into the molecular mechanisms underlying obesity and related disorders.