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

• 批准号: 10332598
• 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
• 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/10332598
• 关键词: ANGPTL3 gene; 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; 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; Time; Tissues; Triglyceride Metabolism; Triglycerides; Variant; Very low density lipoprotein; Work; antagonist; base; 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

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：甘油三酸酯和胆固醇代谢的翻译后控制Angptl3＆ APOBCL清除中的Angptl8 项目摘要 该赠款的目的是阐明失活的Angptl3的脂质降低作用的分子基础 （A3）和Angptl8（A8）。以前我们发现人类A3中的灭活突变与 随着甘油三酸酯（TGS）的循环水平降低。我们表明A3形成具有相关蛋白质的复合物， A8，使脂蛋白脂肪酶（LPL）灭活，这是外周组织中血管内酶，水解循环的 TG。通过增加LPL活性，A3或A8的失活降低了血浆TG水平。尽管有这些进步 在我们的理解中，关于A3和A8如何相互作用以抑制体内LPL的基本问题。 此外，A3的活动独立于A8。 A3的失活显着降低了血浆胆固醇， 以及TG水平。此活动不需要A8或任何已知的肝脂蛋白间隙 途径。我们的小组以及丹·拉德（Dan Rader）的小组表明，需要内皮脂肪酶（EL） A3失活的降低胆固醇作用。该应用的科学前提是阐明 A3和A8抑制作用降低脂质作用的分子机制将导致新的策略 心脏代谢性疾病的预防和治疗。 在AIM 1中，我们将确定在抑制LPL和EL的体内操作的A3/A8和A3的形式， 两种蛋白质均受到翻译后修饰的约束，包括蛋白水解裂解和 寡聚化。我们将根据相对于天然蛋白的活性形式的基本特性 切割（AIM 1A）和化学计量学（AIM 1A），然后净化活跃的复合物并确定其高 分辨率结构（AIM 1C）。在AIM 2中，我们将以分子为特征肝的非规范途径 在A3缺乏症中清除含APOB的脂蛋白（APOBL）的清除率，并测试3个假设 该途径的分子基础：首先，EL刺激的Apobl摄取是接收器介导的内吞 过程（AIM 2A）；第二，El改变了新生VLDL的组成，暴露了Apobl的新配体 肝脏吸收（AIM 2B）。最后，我们将在培养的肝细胞中建立一个公正的遗传筛选 鉴定介导肝脏摄取的受体并在体内验证受体活性（AIM 2C）。 阐明A3和A8改变脂质代谢的分子机制将为您提供新的见解 关键代谢途径。他们还将为新一代降脂剂提供机械基础。 这些目标完成了研究项目1和项目2的目标，以了解是什么监管 脂质的形成，位置和代谢命运，以开发新的药物来治疗心脏代谢 疾病。