Role of PKCbeta in Diet-induced Hypercholesterolemia

PKCbeta 在饮食引起的高胆固醇血症中的作用

基本信息

批准号：
7326829
负责人：
KAMAL D MEHTA
金额：
$ 28.35万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-12-06 至 2009-07-14
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7326829
关键词：
ATP-Binding Cassette Transporters Abbreviations Affect Affinity Aging American Amino Acids Anabolism Animals Apolipoprotein E Apolipoproteins Arts Atherosclerosis Attention Binding Binding Proteins Binding Sites Biochemical Biological Assay Calories Cause of Death Cell physiology Cholesterol Cholesterol Homeostasis Complement Complex Coronary Arteriosclerosis Cyclodextrins Diet Dietary Cholesterol Dietary Fats Doctor of Philosophy Endoplasmic Reticulum Environment Extracellular Signal Regulated Kinases Family Fatty acid glycerol esters Figs - dietary Gene Expression Genes Genetic Goals Golgi Apparatus Hepatic Hepatocyte High Density Lipoproteins Human Hypersensitivity Individual Investigation Knock-out Knowledge LDL Cholesterol Lipoproteins Ligands Link Lipids Lipoproteins Liver Low Density Lipoprotein Receptor Low-Density Lipoproteins MAP Kinase Gene MAPK14 gene MEKKs MEKs Mass Spectrum Analysis Measures Mediating Membrane Mink Mitogen-Activated Protein Kinases Mitogens Mixed Function Oxygenases Modification Molecular Molecular Biology Mus Mutant Strains Mice Nature Phenotype Phosphorylation Phosphotransferases Physiological Physiology Plasma Population Preventive Process Property Protein Binding Protein Isoforms Protein Kinase Protein Kinase C Protein Overexpression Proteins Proteolysis Proteolytic Processing Rate Regulation Regulator Genes Response Elements Risk Factors Role Serum Signal Pathway Signal Transduction Signal Transduction Pathway Societies Squalene Synthetase Sterols Stress Structure Techniques Time Transgenic Mice Transgenic Organisms Twin Studies Work base cholesterol absorption citrate carrier day density dietary excess disability disorder prevention feeding gain of function genetic linkage analysis human MAP3K1 protein hypercholesterolemia i-cholesterol lipid disorder loss of function mutant protein kinase C beta receptor receptor expression response saturated fat sensor site-1 protease tool transcription factor

项目摘要

DESCRIPTION (provided by applicant): Coronary artery disease (CAD) remains the leading cause of death and disability in our society. Of all known risk factors promoting CAD, a high serum level of low-density lipoprotein (LDL)-cholesterol is one of the most important risk factors. The plasma level of this lipoprotein is strongly influenced by genetic factors and the amount of dietary fat and cholesterol; dietary modification remains the cornerstone of CAD prevention. Our knowledge of the regulatory mechanism(s) controlling cholesterol homeostasis in response to dietary cholesterol is limited, as is the role of signaling pathways initiated by alterations in cholesterol levels. Also, the interrelationships between these signaling pathways and sterol response element-binding proteins (SREBPs), as well as the mechanism linking SREBP processing and cholesterol levels are not clear. The emerging picture from our work is that regulation of hepatic LDL receptors, crucial for cholesterol homeostasis, results from the activity of a few interlinked regulatory signaling pathways. We have previously shown, for the first-time, involvement of specific isoforms of protein kinase C (PKC) in the regulation of LDL receptor expression in cultured hepatic cells, possibly through direct modulation of activity by cholesterol. Based on our recent results, we propose a central role for B-isoform of PKC (PKCb) in regulating cholesterol homeostasis via modulating expression of selected genes crucial for this process. In Specific Aim 1, the role of PKCb in cholesterol homeostasis will be established by evaluating the effect of knockout of this ldnase on overall cholesterol homeostasis. Initial studies with PKC(-deficient mice strongly support a central role of this kinase in controlling the responsiveness of plasma cholesterol to the changes in the dietary cholesterol content. Cholesterol metabolism will be compared in detail between normal and PKCb mutants fed special diets. The Specific Aim 2 will compare expression of the hepatic genes critical for cholesterol homeostasis in the above animals. In Specific Aim 3, mechanisms by which PKCb affects SREBP-2 expression and its proteolytic processing, possibly by regulating INSIG- 1 phosphorylation will be examined. Finally, the nature of the isoform-specific interaction between cholesterol and PKCb will be examined in the Specific Aim 4. The photoactive cholesterol probe will be used to define at the molecular level structure(s) and amino acids that produce isoform-specific binding of PKCb to cholesterol. The proposed studies will not only establish the role of PKCb in diet-induced hypercholesterolemia, but will also identify genes regulated by this kinase, to correlate regulatory mechanisms to animal physiology. They will also help understand the complex interactions between environment and genetics leading to atherosclerosis. Accomplishment of the above aims will unravel a central signaling component that may act as a sensor to respond to dietary cholesterol; modulation of its activity may be the preferable mode for the treatment of lipid disorders in the 21st century.

描述（由申请人提供）：冠状动脉疾病（CAD）仍然是我们社会死亡和残疾的主要原因。在所有已知的导致 CAD 的危险因素中，高血清低密度脂蛋白 (LDL) 胆固醇水平是最重要的危险因素之一。这种脂蛋白的血浆水平受到遗传因素以及膳食脂肪和胆固醇含量的强烈影响；饮食调整仍然是预防 CAD 的基石。我们对控制胆固醇稳态以响应膳食胆固醇的调节机制的了解是有限的，由胆固醇水平改变引发的信号通路的作用也是有限的。此外，这些信号通路与甾醇反应元件结合蛋白 (SREBP) 之间的相互关系，以及 SREBP 加工和胆固醇水平之间的联系机制尚不清楚。我们的工作得出的结论是，对胆固醇稳态至关重要的肝脏 LDL 受体的调节是由一些相互关联的调节信号通路的活动引起的。我们之前首次表明，蛋白激酶 C (PKC) 的特定异构体可能通过胆固醇直接调节活性来参与调节培养肝细胞中的 LDL 受体表达。根据我们最近的结果，我们提出 PKC B 亚型 (PKCb) 通过调节对该过程至关重要的选定基因的表达，在调节胆固醇稳态中发挥核心作用。在具体目标 1 中，将通过评估 PKCb 基因敲除对总体胆固醇稳态的影响来确定 PKCb 在胆固醇稳态中的作用。对 PKC(-缺陷小鼠) 的初步研究有力地支持了该激酶在控制血浆胆固醇对饮食胆固醇含量变化的反应中的核心作用。将详细比较正常饮食和喂养特殊饮食的 PKCb 突变体之间的胆固醇代谢。目标 2 将比较上述动物中对胆固醇稳态至关重要的肝脏基因的表达，在具体目标 3 中，PKCb 影响 SREBP-2 表达及其蛋白水解的机制。最后，将在具体目标 4 中检查胆固醇和 PKCb 之间异构体特异性相互作用的性质。光活性胆固醇探针将用于在分子水平上定义结构。 (s) 和产生 PKCb 与胆固醇同工型特异性结合的氨基酸拟议的研究不仅将确定 PKCb 在饮食诱导的高胆固醇血症中的作用，还将鉴定受其调节的基因。激酶，将调节机制与动物生理学相关联。它们还将有助于理解导致动脉粥样硬化的环境和遗传学之间复杂的相互作用。上述目标的实现将揭示一个中央信号传导成分，该成分可以充当对饮食胆固醇做出反应的传感器；调节其活性可能是21世纪治疗脂质紊乱的优选模式。