Mechanistic studies of a PPAR-g mutation that causes lipodystrophy & diabetes

导致脂肪营养不良的 PPAR-g 突变的机制研究

• 批准号: 8321025
• 负责人: Olga Igor Astapova
• 金额: $ 4.72万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-08 至 2014-09-07
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8321025
• 关键词: 2,4-thiazolidinedione; Adipose tissue; Adult; Affect; Binding; Binding Sites; Biological Assay; Cell Line; Cells; Complement; Complex; Consensus; DNA Binding; DNA Binding Domain; DNA Sequence; Data; Development; Diabetes Mellitus; Diabetes prevention; Disease; Doctor of Philosophy; Dyslipidemias; Electrophoretic Mobility Shift Assay; Energy Metabolism; Etiology; Event; Familial partial lipodystrophy; Family; Fibroblasts; Functional disorder; Gene Expression; Gene Expression Microarray Analysis; Gene Expression Profile; Gene Expression Regulation; Gene Targeting; Generations; Genes; Genetic Transcription; Goals; Human; Human Cell Line; Hypertension; Immunoblotting; In Vitro; Inflammation; Inherited; Insulin; Insulin Resistance; Insulin Signaling Pathway; Intracellular Accumulation of Lipids; Knowledge; Ligands; Light; Lipodystrophy; Luciferases; Mediating; Metabolic; Metabolic Diseases; Metabolic syndrome; Microarray Analysis; Molecular; Molecular Biology; Molecular Profiling; Mutation; Non-Insulin-Dependent Diabetes Mellitus; Nuclear Receptors; Obesity; PPAR gamma; Pathogenesis; Pathway interactions; Pattern; Peroxisome Proliferator-Activated Receptors; Pharmaceutical Preparations; Phenotype; Physiological; Play; Polycystic Ovary Syndrome; Population; Prevalence; Prevention; Production; Property; Recruitment Activity; Regulation; Reporter; Reporting; Response Elements; Reverse Transcriptase Polymerase Chain Reaction; Role; Screening procedure; Specificity; Structure; Techniques; Thiazolidinediones; Transcriptional Activation; United States National Institutes of Health; base; chromatin immunoprecipitation; combat; improved; in vivo; insight; insulin sensitivity; insulin sensitizing drugs; loss of function mutation; mitochondrial dysfunction; mutant; promoter; receptor; research study; response

DESCRIPTION (provided by applicant): Although insulin resistance is a key component of type II diabetes, the molecular mechanisms controlling insulin sensitivity have not been fully elucidated. Understanding the etiology of insulin resistance will therefore be of tremendous importance for developing better screening, treatment and prevention targets to combat the rising threat of metabolic disorders. Peroxisome proliferator-activated receptor gamma (PPARg) has been implicated in the insulin signaling pathway as the target of thiazolidinediones, drugs that have recently been employed in the management of insulin-resistant disorders for their insulin-sensitizing effects. PPARg is a ligand-activated nuclear receptor with a well-characterized structure that binds PPAR response elements and regulates transcription of target genes by recruiting coactivators and/or corepressors. Although many PPARg-regulated genes have been identified, the exact set of PPARg target genes that mediate improvements in insulin sensitivity in vivo is largely unknown. The goal of this project is to shed light on this issue by studying a unique, recently discovered PPARg mutation that causes familial partial lipodystrophy (FPLD), an extreme form of type II diabetes. This project will take advantage of the particular properties of this mutation, which makes a conservative single change (E157D) in the DNA binding domain of the receptor. Our preliminary data show that this mutation alters the DNA sequence recognition specificity of the receptor, resulting in a distinctly different pattern of transcription of several known PPARg target genes. These findings led to the hypothesis that forms the basis for this proposal: the E157D PPARg causes diabetes through misregulation of key metabolic genes. There are two specific aims: 1) Characterize the effects of the E157D mutation on DNA binding and transcriptional activation of a set of known PPARg target genes, and 2) Identify the global set of genes that are misregulated by E157D PPARg. Standard in vitro techniques for DNA binding and transcriptional activity will be used to compare mutant and wild type PPARg function. Human cell lines expressing wild-type and mutant PPARg will be generated, and microarray analysis of gene expression as well as chromatin immunoprecipitation analysis of selected genes will be used to identify genes misregulated by E157D PPARg. RELEVANCE. Results from this study will identify genes or sets of genes that were not previously recognized as being involved in the etiology of metabolic diseases such as lipodystrophy and in particular diabetes. This knowledge may advance possibilities for screening, treatment and prevention of diabetes and other metabolic diseases.

描述(由申请人提供)： 虽然胰岛素抵抗是II型糖尿病的一个重要组成部分，但控制胰岛素敏感性的分子机制尚未完全阐明。因此，了解胰岛素抵抗的病因对于制定更好的筛查、治疗和预防目标以对抗日益增长的代谢紊乱威胁具有极其重要的意义。过氧化物酶体增殖物激活受体γ(PPARg)作为噻唑烷二酮类药物的靶点参与了胰岛素信号转导通路，这些药物最近被用于治疗胰岛素抵抗疾病，因为它们具有胰岛素增敏作用。PPARG是一种配体激活的核受体，具有与PPAR反应元件结合的结构，并通过招募辅激活子和/或辅阻遏子来调节靶基因的转录。虽然已经鉴定了许多PPARg调节基因，但在体内介导胰岛素敏感性改善的PPARg靶基因的确切集合在很大程度上是未知的。该项目的目标是通过研究最近发现的一种独特的PPARg突变来阐明这一问题，该突变会导致家族性部分脂肪营养不良(FPLD)，这是II型糖尿病的一种极端形式。该项目将利用这种突变的特殊性质，它使受体的DNA结合域发生保守的单一变化(E157D)。我们的初步数据显示，这种突变改变了受体的DNA序列识别特异性，导致几个已知的PPARg靶基因的转录模式截然不同。这些发现导致了形成这一提议的基础的假设：E157D PPARg通过对关键代谢基因的错误调节而导致糖尿病。有两个特定的目标：1)表征E157D突变对一组已知PPARg靶基因的DNA结合和转录激活的影响，以及2)识别由E157D PPARg错误调控的全局性基因集。标准的DNA结合和转录活性的体外技术将用于比较突变型和野生型PPARg的功能。将建立表达野生型和突变型PPARg的人类细胞系，并将使用基因表达的微阵列分析以及选定基因的染色质免疫沉淀分析来识别被E157D PPARg错误调控的基因。 关联性。这项研究的结果将确定以前没有的基因或基因集 被认为与代谢性疾病，如脂肪营养不良，特别是糖尿病的病因学有关。这种知识可能会促进糖尿病和其他代谢性疾病的筛查、治疗和预防的可能性。