Control of Sterol and Lipoprotein Homeostasis by miRNA

miRNA 对甾醇和脂蛋白稳态的控制

• 批准号: 8816115
• 负责人: Angel Baldan
• 金额: $ 36.94万
• 依托单位: SAINT LOUIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-05-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8816115
• 关键词: ATP binding cassette transporter 1; Accounting; Address; Adenoviruses; Animals; Anti-Inflammatory Agents; Anti-inflammatory; Antisense Oligonucleotides; Apolipoprotein E; Arterial Fatty Streak; Arteries; Atherosclerosis; Back; Bile Acids; Bile fluid; Biliary; Biological; Biology; Bone Marrow; Cells; Cessation of life; Cholestasis; Cholesterol; Cholesterol Homeostasis; Cholic Acids; Clinical; Complex; Data; Development; Diet; Down-Regulation; Dyslipidemias; Excretory function; Feces; Genes; Goals; Health; Hepatic; Hepatocyte; High Density Lipoprotein Cholesterol; High Density Lipoproteins; Homeostasis; Human; Intervention; Intestines; Intrahepatic Cholestasis; Introns; LDL Cholesterol Lipoproteins; Label; Laboratories; Lead; Link; Lipoproteins; Liver; Low Density Lipoprotein Receptor; Measures; Metabolic; Metabolism; MicroRNAs; Modeling; Mus; Myocardial Infarction; Oligonucleotides; Outcome; Output; Pathway interactions; Patients; Peripheral; Peripheral arterial disease; Phospholipids; Physiological; Plasma; Property; Proteome; Publishing; Regimen; Reporting; Risk Factors; Role; SRE-2 binding protein; Serum; Sterols; Stroke; Subfamily lentivirinae; Testing; Tissues; atherogenesis; atheroprotective; base; cardiovascular disorder risk; cholesterol control; dietary supplements; feeding; hypercholesterolemia; improved; in vivo; mRNA Expression; mRNA Precursor; macrophage; novel; overexpression; protein expression; research study; response; reverse cholesterol transport; sterol homeostasis

DESCRIPTION (provided by applicant): Atherosclerosis is the primary cause of heart attack, stroke, and peripheral artery disease, which collectively account for >30% of all deaths in the US. Multiple studies recognized abnormal cholesterol homeostasis as a risk factor for the development of atherosclerosis. We and others have recently reported on miR-33, a conserved microRNA that is encoded within intron 16 of SREBP-2. The clinical importance of SREBP-2 is revealed in hypercholesterolemic patients treated with statins, which reduce LDL-cholesterol levels by increasing hepatic expression of SREBP-2 and its target the LDL-receptor. Our published and preliminary studies show that physiological targets of miR-33 include ABCA1, a transporter critical for HDL lipidation and reverse cholesterol transport, and ATP8B1, a phospholipid flippase linked to intrahepatic cholestasis. The broad goal of this proposal is to determine the role of miR-33 on cholesterol, bile and lipoprotein homeostasis. We hypothesize that miR-33 controls key aspects of sterol mobilization, bile excretion and HDL metabolism. Importantly, since statins are usually prescribed to hypercholesterolemic patients, and statins induce the expression of miR-33, we speculate that statin-treated patients will have elevated levels of miR-33 and persistent down regulation of ABCA1 and ATP8B1 by miR-33. To address these questions, we propose the following 3 specific aims: 1) Determine the role of miR-33 in hepatic sterol homeostasis in primary hepatocytes and in mice, by measuring the effect of over expression or silencing of miR-33 on lipoprotein secretion and bile excretion; 2) Test the hypothesis that altered macrophage miR-33 expression results in changes in reverse cholesterol transport and atherosclerotic lesion size, by performing experiments in vivo to determine the role of macrophage miR-33 expression on cholesterol -/- mobilization and progression of atherosclerotic lesions in Ldlr mice ; and 3) Test the hypothesis that systemic silencing of miR-33 is atheroprotective in vivo, by characterizing the composition and biological properties of HDL generated following systemic silencing of miR-33, and by evaluating whether anti-miR-33 oligonucleotides synergize with the atheroprotective effects of statins in ApoE*3Leiden W hCETP mice. There are still multiple aspects of cholesterol homeostasis, cholestasis and atherogenesis that remain obscure. Our data suggest that the cholesterol-miR-33 axis modulates key aspects of hepatocyte and macrophage biology. We anticipate that our studies will provide new clues into the complex regulatory networks that control intracellular cholesterol levels, bile excretion and circulating lipoproteins. If our hypothesis is true, miR-33 might be a target for novel therapies to manage dyslipidemias and/or cholestasis.

描述（由申请人提供）：动脉粥样硬化是心脏病发作、中风和外周动脉疾病的主要原因，这些疾病合计占美国所有死亡人数的 30% 以上。多项研究发现胆固醇稳态异常是动脉粥样硬化发生的危险因素。我们和其他人最近报道了 miR-33，这是一种保守的 microRNA，在 SREBP-2 的内含子 16 内编码。 SREBP-2 的临床重要性在接受他汀类药物治疗的高胆固醇血症患者中得到体现，他汀类药物通过增加 SREBP-2 及其靶点 LDL 受体的肝脏表达来降低 LDL 胆固醇水平。我们已发表的初步研究表明，miR-33 的生理靶标包括 ABCA1（一种对 HDL 脂化和反向胆固醇转运至关重要的转运蛋白）和 ATP8B1（一种与肝内胆汁淤积相关的磷脂翻转酶）。该提案的总体目标是确定 miR-33 对胆固醇、胆汁和脂蛋白稳态的作用。我们假设 miR-33 控制甾醇动员、胆汁排泄和 HDL 代谢的关键方面。重要的是，由于他汀类药物通常用于高胆固醇血症患者，并且他汀类药物会诱导 miR-33 的表达，因此我们推测接受他汀类药物治疗的患者 miR-33 水平升高，并且 miR-33 对 ABCA1 和 ATP8B1 持续下调。为了解决这些问题，我们提出以下 3 个具体目标： 1) 通过测量 miR-33 的过度表达或沉默对脂蛋白分泌的影响，确定 miR-33 在原代肝细胞和小鼠肝甾醇稳态中的作用。胆汁排泄； 2) 通过体内实验确定巨噬细胞 miR-33 表达对胆固醇 -/- 动员和动脉粥样硬化病变进展的作用，检验巨噬细胞 miR-33 表达改变导致胆固醇逆向转运和动脉粥样硬化病变大小变化的假设在 Ldlr 小鼠中； 3) 通过表征 miR-33 系统性沉默后产生的 HDL 的组成和生物学特性，并评估抗 miR-33 寡核苷酸是否与动脉粥样硬化具有协同作用，测试 miR-33 系统性沉默在体内具有动脉粥样硬化保护作用的假设他汀类药物对 ApoE*3Leiden W hCETP 小鼠的影响。胆固醇稳态、胆汁淤积和动脉粥样硬化形成的多个方面仍然不清楚。我们的数据表明胆固醇-miR-33 轴调节肝细胞和巨噬细胞生物学的关键方面。我们预计我们的研究将为控制细胞内胆固醇水平、胆汁排泄和循环脂蛋白的复杂调节网络提供新线索。如果我们的假设成立，miR-33 可能成为治疗血脂异常和/或胆汁淤积的新疗法的靶点。