Regulation of Cellular Cholesterol Homeostasis

细胞胆固醇稳态的调节

• 批准号: 7840714
• 负责人: PETER J. ESPENSHADE
• 金额: $ 20.52万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-15 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7840714
• 关键词: Adult; Animal Model; Atherosclerosis; Binding; Biochemical; Biological; Blood; Cardiovascular system; Cell membrane; Cells; Cellular biology; Cholesterol; Cholesterol Homeostasis; Collection; Coronary Arteriosclerosis; Cryptococcus neoformans; Essential Genes; Eukaryotic Cell; Event; Feedback; Fission Yeast; Genes; Genetic Models; Genetic Screening; Genetic Transcription; Goals; Golgi Apparatus; Haploidy; Health; Heart Diseases; Homeostasis; Homologous Gene; Knowledge; Lipids; Lipoproteins; Mammalian Cell; Mammals; Measures; Mediating; Membrane; Membrane Fluidity; Membrane Proteins; Modeling; Molecular; Molecular Genetics; Monitor; Mutagenesis; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Organelles; Oxygen; Pathology; Pathway interactions; Peptide Hydrolases; Production; Protein Binding Domain; Proteins; Proteolysis; Regulation; Reporter Genes; Research; Screening procedure; Serum; Site; Sterols; System; Testing; Therapeutic; Translating; United States; Whole Organism; Widespread Disease; Yeasts; base; cell growth regulation; cholesterol biosynthesis; expectation; genetic selection; improved; novel; pathogen; prevent; public health relevance; receptor; research study; response; sensor; sterol homeostasis; transcription factor; uptake; yeast genetics

DESCRIPTION (provided by applicant): Cellular lipid homeostasis is required to maintain bilayer fluidity, membrane impermeability, and organelle identity. Disturbances in systemic lipid homeostasis lie at the core of the pathologies for both coronary artery disease and obesity related type II diabetes. The long-term goal of this research is to translate knowledge of cellular regulatory events to that of the whole organism and to advance our understanding of these increasingly widespread diseases. As a first step toward this goal, we will use cholesterol as a model lipid to understand how cells measure levels of these largely insoluble molecules and in turn modulate their production. Cholesterol homeostasis in mammalian cells is regulated by a feedback mechanism that monitors the level of cholesterol in membranes and alters transcription of genes required for cholesterol supply. Transcription of these genes is controlled by the ER membrane-bound transcription factor called SREBP that is activated and released from the membrane by proteolysis in sterol-depleted cells. To accelerate discovery of sterol homeostasis regulators, we are studying the SREBP pathway in the fission yeast Schizosaccharomyces pombe. Yeast SREBP, called Sre1, functions in a new oxygen sensing pathway that mediates adaptation of cells to low oxygen. Interestingly, sterols regulate Sre1 activity through a novel mechanism in fission yeast, and evidence also indicates that Sre1 cleavage is mediated by a unique proteolytic system. In this project, a combination of genetic, molecular, and biochemical approaches will be used to accomplish the following specific aims: 1) To identify genes required for Sre1 cleavage using a genetic selection; 2) To define the machinery for Sre1 cleavage; and 3) To define the mechanism of sterol-regulated Sre1 cleavage. The long-term goal of this project is to use S. pombe as a genetic model to understand how cells measure levels of insoluble, membrane-embedded cholesterol. The expectation is that these studies will describe new mechanisms for lipid sensing and proteolysis that will advance our understanding of the mammalia SREBP pathway and eukaryotic cell biology. PUBLIC HEALTH RELEVANCE: Heart disease is a leading killer of adults in the United States. Proper regulation of cellular cholesterol homeostasis is integral to cardiovascular health. In this project, we will use yeast as a genetic model organism to define new mechanisms for regulation of cholesterol homeostasis with the goal of identifying improved therapeutic strategies for lowering serum cholesterol and preventing heart disease.

描述（由申请方提供）：细胞脂质稳态是维持双层流动性、膜不透性和细胞器特性所必需的。全身脂质稳态的紊乱是冠状动脉疾病和肥胖相关的II型糖尿病的病理学的核心。这项研究的长期目标是将细胞调节事件的知识转化为整个生物体的知识，并促进我们对这些日益广泛的疾病的理解。作为实现这一目标的第一步，我们将使用胆固醇作为模型脂质，以了解细胞如何测量这些大部分不溶性分子的水平，进而调节它们的产生。哺乳动物细胞中的胆固醇稳态由反馈机制调节，该反馈机制监测膜中胆固醇的水平并改变胆固醇供应所需的基因的转录。这些基因的转录由称为SREBP的ER膜结合转录因子控制，该转录因子在甾醇耗尽的细胞中通过蛋白水解被激活并从膜释放。为了加速发现固醇稳态调节剂，我们正在研究裂殖酵母粟酒裂殖酵母中的SREBP途径。酵母SREBP，称为Sre 1，在一个新的氧传感途径中发挥作用，介导细胞对低氧的适应。有趣的是，甾醇通过一种新的机制在裂殖酵母中调节Sre 1活性，并且证据还表明Sre 1切割是由独特的蛋白水解系统介导的。本研究将综合运用遗传学、分子生物学和生物化学方法来实现以下具体目标：1）通过遗传选择鉴定Sre 1切割所需的基因; 2）确定Sre 1切割的机制; 3）确定甾醇调控的Sre 1切割机制。该项目的长期目标是使用S。pombe作为遗传模型，以了解细胞如何测量不溶性，膜嵌入胆固醇的水平。期望这些研究将描述脂质传感和蛋白质水解的新机制，这将促进我们对哺乳动物SREBP通路和真核细胞生物学的理解。公共卫生相关性：心脏病是美国成年人的主要杀手。细胞胆固醇稳态的适当调节是心血管健康不可或缺的。在这个项目中，我们将使用酵母作为遗传模式生物来定义胆固醇稳态调节的新机制，目的是确定降低血清胆固醇和预防心脏病的改进治疗策略。