Cellular and Molecular Mechanisms of SH2B1 Mutations That Cause Profound Childhood Obesity

导致儿童严重肥胖的 SH2B1 突变的细胞和分子机制

• 批准号: 9456743
• 负责人: CHRISTIN CARTER-SU
• 金额: $ 45.42万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9456743
• 关键词: Adult; Affect; Aggressive behavior; Atherosclerosis; Behavior; Behavioral; Body Size; Body Weight; Brain; Brain region; CRISPR/Cas technology; Cell Nucleus; Cell membrane; Complex; Cultured Cells; DNA Binding; Development; Diabetes Mellitus; Disease; Dyslipidemias; Epidemic; Event; Exhibits; Expenditure; FOLH1 gene; Feeding behaviors; Gene Expression; Genes; Genetic Transcription; Goals; Health; Heart Diseases; Hippocampus (Brain); Homeostasis; Human; Hyperphagia; Hypertension; Hypothalamic structure; Impairment; Individual; Insulin; Insulin Resistance; Investigation; Knockout Mice; Knowledge; Lead; Leptin; Ligands; Maintenance; Malignant Neoplasms; Membrane; Metabolic syndrome; Mission; Molecular; Morbid Obesity; Movement; Mus; Mutation; Neurites; Neurons; Non-Insulin-Dependent Diabetes Mellitus; Nuclear; Obesity; Pathogenicity; Peptides; Physiology; Play; Population; Post-Translational Protein Processing; Protein Tyrosine Kinase; Public Health; Regulation; Regulator Genes; Research; Risk Factors; Role; SH2B gene; Safety; Scaffolding Protein; Signal Pathway; Signal Transduction; Signaling Protein; Social isolation; Speech Delay; Techniques; Testing; Therapeutic Intervention; United States; United States National Institutes of Health; Youth; base; cohort; early onset; energy balance; experimental study; human disease; in vivo; innovation; insight; leptin receptor; man; mouse model; mutant; neural circuit; neuronal circuitry; new therapeutic target; novel; obesity in children; paraventricular nucleus; protein function; receptor; response; scaffold; targeted treatment; tool; transcription factor

ABSTRACT Obesity is a major health problem associated with a significant increase in metabolic syndrome, diabetes, and heart disease. Thus, obesity demands an in-depth understanding of its causes at the cellular, molecular and organismal level. In an exciting new development, identification of human mutations in SH2B1 that associate with profound childhood obesity implicate the scaffold protein SH2B1 as a critical regulator of body weight, in- sulin sensitivity and behavior. There is a fundamental gap in our understanding of how SH2B1 regulates neural circuitry that maintains energy homeostasis and how human obesity mutations in SH2B1 disrupt that circuitry and contribute to obesity. Our long-term goal is to identify novel key signaling proteins and/or gene regulatory events that are regulated by SH2B1, critical for establishing and maintaining neural circuits important for nor- mal feeding behavior and energy balance, can be targeted for therapeutic intervention for obesity, insulin- resistance and/or maladaptive behavior. Primary neurons, novel mouse models and cultured cells will be used to test the central hypothesis that SH2B1 is crucial for the establishment and maintenance of neural circuits important for normal feeding behavior and energy balance. Mechanistically, SH2B1 serves as a scaffold pro- tein that enhances signaling pathways at the plasma membrane and cycles to the nucleus, both are required for regulating gene transcription and neurite outgrowth. Human disease mutations impair a subset of these re- sponses. The specific aims are: 1) Determine neurotrophic ligand signaling pathways regulated by SH2B1 and impaired by the human mutations; 2) Determine how nuclear SH2B1, which is required for neurite outgrowth, enhances gene expression and the human mutations impair that enhancement; and 3) Define the role for SH2B1 in neural circuit formation and transcription in hypothalamic neurons implicated in energy balance. This research is innovative because: 1) SH2B1 was recently implicated as a human obesity gene; 2) newly identi- fied SH2B1 mutations provide powerful tools to study the causes of obesity; 3) the concept of coordinating an integrated response to neurotrophic ligands by movement of scaffold proteins between the plasma membrane and the nucleus is novel; and 4) many of the proposed techniques and mouse models are cutting edge, includ- ing CRISPR/Cas9 technology to delete or edit Sh2b1, mouse models to study the effect of SH2B1 on neuronal projections, studying gene expression within the small population of LepRb neurons in the hypothalamus, and the unique Sh2b1P322S mouse that enables study of the impact of a human SH2B1 mutation in intact mice and isolated neurons. The proposed research is significant because it will provide critical insight into the cellular and molecular mechanisms by which SH2B1 and the human mutations affect the function of neurons, including those that regulate body weight, and how complex, multi-protein based signals are coordinated between plas- ma membrane receptors and the nucleus. This insight will advance our understanding of neuron function and identify potential new therapeutic targets for obesity, insulin resistance and/or maladaptive behavior.

抽象的 肥胖是一个主要的健康问题，与代谢综合征、糖尿病和糖尿病的显着增加相关 心脏病。因此，肥胖需要从细胞、分子和机制方面深入了解其原因。 有机体水平。在一项令人兴奋的新进展中，鉴定了与 SH2B1 相关的人类突变 严重的儿童肥胖症表明支架蛋白 SH2B1 是体重的关键调节因子， 苏林敏感性和行为。我们对 SH2B1 如何调节神经的理解存在根本性差距 维持能量稳态的电路以及 SH2B1 中的人类肥胖突变如何破坏该电路 并导致肥胖。我们的长期目标是识别新型关键信号蛋白和/或基因调控 由 SH2B1 调节的事件，对于建立和维持正常的神经回路至关重要 不良喂养行为和能量平衡，可以作为肥胖、胰岛素治疗干预的目标 抵抗和/或适应不良行为。将使用原代神经元、新型小鼠模型和培养细胞 检验 SH2B1 对于神经回路的建立和维持至关重要的中心假设 对于正常的进食行为和能量平衡很重要。从机制上讲，SH2B1充当支架亲 tein 增强质膜信号通路和细胞核循环，两者都是必需的 用于调节基因转录和神经突生长。人类疾病突变会损害其中的一部分 响应。具体目标是： 1) 确定 SH2B1 调节的神经营养配体信号通路和 受到人类突变的损害； 2) 确定神经突生长所需的核 SH2B1 如何 增强基因表达，而人类突变会损害这种增强； 3) 定义角色 SH2B1 在与能量平衡有关的下丘脑神经元的神经回路形成和转录中的作用。这 该研究具有创新性，因为：1）SH2B1 最近被认为是人类肥胖基因； 2）新识别 SH2B1 突变为研究肥胖原因提供了有力的工具； 3）协调的概念 通过质膜之间支架蛋白的移动对神经营养配体的综合反应 并且核心是新颖的； 4）许多提出的技术和小鼠模型都是前沿的，包括- 利用CRISPR/Cas9技术删除或编辑Sh2b1，小鼠模型研究SH2B1对神经元的影响 预测，研究下丘脑 LepRb 神经元小群体内的基因表达，以及 独特的 Sh2b1P322S 小鼠能够研究人类 SH2B1 突变对完整小鼠的影响 孤立的神经元。拟议的研究意义重大，因为它将提供对细胞的重要见解 SH2B1 和人类突变影响神经元功能的分子机制，包括 那些调节体重的信号，以及如何在质体之间协调复杂的、基于多蛋白质的信号 ma膜受体和细胞核。这一见解将增进我们对神经元功能和 确定肥胖、胰岛素抵抗和/或适应不良行为的潜在新治疗靶点。