Post-translational Control of Triglyceride and Cholesterol Metabolism by ANGPTL3 & ANGPTL8 in ApoBCL Clearance

ANGPTL3 对甘油三酯和胆固醇代谢的翻译后控制

基本信息

批准号：
10543874
负责人：
Helen Haskell Hobbs
金额：
$ 57.4万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-01 至 2026-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10543874
关键词：
ANGPTL3 gene Acceleration Affect Angiopoietins Antibody Specificity Apolipoprotein E Apolipoproteins B Biochemical Biological Cardiometabolic Disease Cells Cholesterol Cholesterol Homeostasis Clinical Trials Complement Complex Coronary heart disease Cultured Cells DNA Sequence Defect Development Disease Enzymes Family member Fatty Acids Female Functional disorder Generations Genetic Genetic Screening Genotype Goals Grant Hepatic Hepatocyte Human Hydrolysis Hypertriglyceridemia Knockout Mice LIPG gene Laboratories Ligands Link Lipase Lipids Lipoprotein (a)Lipoproteins Liver Location Low-Density Lipoproteins Mediating Metabolic Metabolic Pathway Metabolism Molecular Mus Mutation Mycoplasma New Agents Pathway interactions Peripheral Pharmaceutical Preparations Phenotype Plasma Plasmids Post-Translational Protein Processing Prevention strategy Process Program Research Project Grants Property Proteins Published Comment Research Project Grants Residual state Resolution Role Route Sample Size Structure Testing Tissues Triglyceride Metabolism Triglycerides Variant Very low density lipoprotein Work antagonist candidate identification cardiovascular risk factor experimental study genetic approach genetic manipulation in vitro activity in vivo insight lipid metabolism lipoprotein lipase male novel strategies protein function receptor reverse genetics routine screening scavenger receptor sex stoichiometry success syndecan therapeutic development uptake

项目摘要

PROJECT 3: Post-translational Control of Triglyceride and Cholesterol Metabolism by ANGPTL3 & ANGPTL8 in ApoBCL Clearance PROJECT SUMMARY The goal of this grant is to elucidate the molecular basis of the lipid-lowering effects of inactivating ANGPTL3 (A3) and ANGPTL8 (A8). Previously we discovered that inactivating mutations in A3 in humans are associated with reduced circulating levels of triglycerides (TGs). We showed that A3 forms a complex with a related protein, A8, to inactivate lipoprotein lipase (LPL), an intravascular enzyme in peripheral tissues that hydrolyzes circulating TG. Inactivation of either A3 or A8 reduced plasma TG levels by increasing LPL activity. Despite these advances in our understanding, fundamental questions remain about how A3 and A8 interact to inhibit LPL in vivo. Moreover, A3 has activities that are independent of A8. Inactivation of A3 dramatically lowers plasma cholesterol, as well as TG levels. This activity does not require A8 or any of the known hepatic lipoprotein clearance pathways. Our group, and that of Dan Rader’s, has shown that endothelial lipase (EL) is needed for the cholesterol-lowering effects of A3 inactivation. The scientific premise of this application is that elucidating the molecular mechanisms underlying the lipid-lowering effects of A3 and A8 inhibition will lead to new strategies for the prevention and treatment of cardiometabolic disorders. In AIM 1 we will determine the forms of A3/A8 and A3 that are operative in vivo in inhibiting LPL and EL, respectively. Both proteins are subject to post-translational modifications, including proteolytic cleavage and oligomerization. We will define the basic properties of the active forms of the native proteins with respect to cleavage (Aim 1A) and stoichiometry (Aim 1A), before purifying the active complexes and determining their high resolution structures (Aim 1C). In AIM 2 we will characterize molecularly the noncanonical pathway for hepatic clearance of ApoB-containing lipoproteins (ApoBL) in A3 deficiency and test 3 hypotheses regarding the molecular basis for this pathway: First, that EL-stimulated ApoBL uptake is a receptor-mediated endocytic process (Aim 2A); Second, that EL alters the composition of nascent VLDL, exposing a new ligand for ApoBL uptake by the liver (Aim 2B). Finally, we will establish an unbiased genetic screen in cultured hepatocytes to identify the receptor that mediates ApoBL uptake by liver and validate receptor activity in vivo (Aim 2C). Elucidating the molecular mechanisms by which A3 and A8 alter lipid metabolism will provide new insights into key metabolic pathways. They will also provide a mechanistic basis for a new generation of lipid-lowering agents. These goals complement the aims of Research Project 1 and Project 2 to understand what regulates the formation, location, and metabolic fate of lipids so as to develop new agents for the treatment of cardiometabolic disorders.

项目 3：ANGPTL3 对甘油三酯和胆固醇代谢的翻译后控制 & ApoBCL 清除中的 ANGPTL8 项目概要该资助的目的是阐明灭活 ANGPTL3 降脂作用的分子基础 (A3) 和 ANGPTL8 (A8) 之前我们发现人类 A3 的失活突变相关。随着甘油三酯 (TG) 循环水平的降低，我们发现 A3 与相关蛋白形成复合物， A8，使脂蛋白脂肪酶 (LPL) 失活，脂蛋白脂肪酶是外周组织中的一种血管内酶，可水解循环系统尽管有这些进展，A3 或 A8 的失活仍会通过增加 LPL 活性来降低血浆 TG 水平。根据我们的理解，关于 A3 和 A8 如何相互作用以抑制体内 LPL 的基本问题仍然存在。此外，A3 具有独立于 A8 的活性，A3 失活可显着降低血浆胆固醇，以及 TG 水平，不需要 A8 或任何已知的肝脂蛋白清除。我们的团队和 Dan Rader 的团队已经表明，内皮脂肪酶 (EL) 是该过程所必需的。 A3 失活的降低胆固醇作用该应用的科学前提是阐明 A3 失活的胆固醇降低作用。 A3 和 A8 抑制的降脂作用背后的分子机制将导致新的策略预防和治疗心脏代谢紊乱。在 AIM 1 中，我们将确定在体内有效抑制 LPL 和 EL 的 A3/A8 和 A3 的形式，两种蛋白质分别受到翻译后修饰，包括蛋白水解和切割。我们将定义天然蛋白质活性形式的基本特性。裂解（目标 1A）和化学计量（目标 1A），然后纯化活性复合物并确定其高浓度分辨率结构（目标 1C）在 AIM 2 中，我们将从分子角度描述肝脏的非典型途径。 A3 缺乏症中含 ApoB 的脂蛋白 (ApoBL) 的清除率和检验 3 个假设该途径的分子基础：首先，EL 刺激的 ApoBL 摄取是受体介导的内吞作用过程（目标 2A）；其次，EL 改变新生 VLDL 的组成，暴露 ApoBL 的新配体最后，我们将在培养的肝细胞中建立无偏基因筛选，以检测肝脏的摄取情况。鉴定介导肝脏摄取 ApoBL 的受体并验证体内受体活性（目标 2C）。阐明 A3 和 A8 改变脂质代谢的分子机制将为我们提供新的见解它们还将为新一代降脂剂提供机制基础。这些目标补充了研究项目 1 和项目 2 的目标，以了解是什么调节了脂质的形成、定位和代谢命运，从而开发治疗心脏代谢疾病的新药物失调。