MicroRNAs regulating plasma LDL and HDL

血浆高低密度脂蛋白和低高密度脂蛋白水平是心血管疾病的危险因素。MicroRNAs (MIR)是一种非编码的内源性小RNA，靶向多条途径，调节生理功能。 因为miRs调节不同的生物途径，我们假设miRs存在于自然界中， 可能同时降低低密度脂蛋白和升高高密度脂蛋白。为了发现它们，我们筛选了一个人类MIR文库 并鉴定出miR-1200可降低apoB(低密度脂蛋白支架蛋白)并增加apoAI(主要高密度脂蛋白 蛋白质)从人肝癌细胞分泌。我们建议找出miR-1200如何降低apoB 分泌，增加载脂蛋白AI分泌，增强肝脏脂肪酸氧化(FAO)调节血浆 脂蛋白和减少动脉粥样硬化而不会引起小鼠的肝骨质疏松症。 目的1：调节小鼠血浆脂蛋白与动脉粥样硬化的生理机制。(A) 我们将询问miR-1200对APOE-/-和LDLR-/-患者血浆脂蛋白和动脉粥样硬化的影响 老鼠。体重增加、VO2、VCO2、活动度和饲喂参数的进一步全面变化 与血浆中的脂蛋白、葡萄糖、细胞因子、趋化因子和转氨酶一样，也要进行测定。 MiR-1200在不同组织中的表达及其对肝脏靶基因和调控基因的影响 将研究脂类、脂类合成和脂肪酸氧化(FAO)。此外，我们将评估是否 MIR-1200能够预防高脂饮食喂养的野生型小鼠因饮食导致的肥胖。(B)我们会评估 MiR-1200调节肝脏载脂蛋白B和载脂蛋白AI分泌从而调节血浆低密度脂蛋白和 高密度脂蛋白水平。(C)我们将检验miR-1200调节血浆低密度脂蛋白和高密度脂蛋白水平的假设，以及 肝脏粮农组织通过调节APOB、BCL11B和NCOR1基因的表达。(D)我们会问，架空的 高密度脂蛋白具有较强的胆固醇外流和反向转运功能，具有抗炎和抗炎作用。 氧化剂。我们预计，增加肝脏miR-1200水平将(1)降低血浆低密度脂蛋白，(2)升高高密度脂蛋白， (3)增加胆固醇的反向转运；(4)加强粮农组织。通过这些机制，miR-1200将 减少动脉粥样硬化和饮食引起的肥胖。 目的2：miR-1200调节脂质代谢的分子机制：(A)降低 载脂蛋白B分泌：我们将(1)检测转染人原代肝细胞的mRNA和蛋白水平 使用miR-1200或控制miR，(2)确定miR-1200是否与种子序列相互作用以增强 ApoB基因转录后降解。(B)增加载脂蛋白AI分泌的机制：WE 假设miR-1200减少了BCL11B的表达，从而增加了ApoAI的转录。 将进行实验以(1)确定BCL11B受miR-1200调控，(2)证明 BCL11B抑制载脂蛋白AI的表达，(3)鉴定载脂蛋白AI启动子中BCL11B的结合位点(S)，以及 (4)确定在miR-1200表达细胞中，BCL11B是否与ApoAI启动子结合较少。这些 研究将确定一种新的调控载脂蛋白AI表达的机制。(C)增加粮农组织的机制： 我们假设miR-1200通过抑制NCOR1来增强粮农组织。我们将确立这一点 MIR-1200与NCOR1 mRNA的3‘-UTR相互作用，促进其降解，从而增加粮农组织的产量。 进一步，我们将证明miR-1200调节NCOR1与MCAD和CPT1启动子的结合。 这些研究将提供概念上的证据，证明存在不同的MIR调节血浆 脂蛋白。此外，他们还将解释参与调节血浆的分子机制。 脂蛋白和肝脏粮农组织。这些研究可能表明，miR-1200可能会降低或防止饮食- 诱导肥胖，减少动脉粥样硬化，而不会引起脂肪变性和升高血浆 转氨酶。这些研究可能指出miR-1200可能是一种潜在的治疗药物。 肥胖和动脉粥样硬化。

Plasma high LDL and low HDL cholesterol levels are risk factors for cardiovascular diseases. MicroRNAs (miRs), small non-coding endogenous RNAs, target multiple pathways and regulate physiologic functions. Because miRs modulate diverse biological pathways, we hypothesized that miRs exist in nature that might simultaneously lower LDL and increase HDL. To discover them, we screened a human miRs library and identified miR-1200 that decreased apoB (LDL scaffold protein) and increased apoAI (major HDL protein) secretion from human hepatoma cells. We propose to find out how miR-1200 decreases apoB secretion, increases apoAI secretion, and enhances hepatic fatty acid oxidation (FAO) to modulate plasma lipoproteins and reduce atherosclerosis without causing hepatosteatosis in mice. Aim 1: Physiological mechanisms modulating plasma lipoproteins and atherosclerosis in mice. (A) We will interrogate the effects of miR-1200 on plasma lipoproteins and atherosclerosis in Apoe–/– and Ldlr–/– mice. Further comprehensive changes in weight gain, VO2, VCO2, activity and feeding parameters as well as in plasma lipids, lipoproteins, glucose, cytokines, chemokines and transaminases will be determined. Accretions of miR-1200 in different tissues and its consequences on target and control genes, hepatic lipids, lipid synthesis and fatty acid oxidation (FAO) will be studied. Additionally, we will evaluate whether miR-1200 is able to prevent diet induced obesity in wild type mice fed a high fat diet. (B) We will evaluate the hypothesis that miR-1200 regulates hepatic apoB and apoAI secretion to modulate plasma LDL and HDL levels. (C) We will test the hypothesis that miR-1200 modulates plasma LDL and HDL levels, and hepatic FAO by regulating APOB, BCL11B and NCOR1 gene expression. (D) We will ask if the elevated HDL is competent in cholesterol efflux and reverse cholesterol transport and is anti-inflammatory and anti- oxidant. We foresee that increasing hepatic miR-1200 levels will (1) reduce plasma LDL, (2) augment HDL, (3) increase reverse cholesterol transport, and (4) enhance FAO. Via these mechanisms, miR-1200 will reduce atherosclerosis and diet-induced obesity. Aim 2: Molecular mechanisms regulating lipid metabolism by miR-1200: (A) Mechanisms decreasing apoB secretion: We will (1) measure mRNA and protein levels in human primary hepatocytes transfected with miR-1200 or Control miR, (2) determine if miR-1200 interacts with seed sequence to enhance posttranscriptional degradation of apoB mRNA. (B) Mechanisms increasing apoAI secretion: We hypothesize that miR-1200 reduces BCL11B expression, a repressor, to increase ApoaI transcription. Experiments will be conducted to (1) establish that BCL11B is regulated by miR-1200, (2) demonstrate if BCL11B represses apoAI expression, (3) identify the binding site(s) for BCL11B in the ApoaI promoter, and (4) determine whether BCL11B binds less to the ApoaI promoter in miR-1200–expressing cells. These studies will identify a novel mechanism of regulating apoAI expression. (C) Mechanisms increasing FAO: We hypothesize that miR-1200 enhances FAO by repressing NCOR1, a repressor. We will establish that miR-1200 interacts with the 3ˊ-UTR of NCOR1 mRNA and enhances its degradation to increase FAO. Further, we will show that miR-1200 modulates the binding of NCOR1 to MCAD and CPT1 promoter. These studies will provide proof of concept that there are miRs that differentially regulate plasma lipoproteins. Further, they will explain molecular mechanisms involved in the regulation of plasma lipoproteins and hepatic FAO. These studies may show that miR-1200 can potentially lower or prevent diet- induced obesity and reduce atherosclerosis without causing steatosis and increasing plasma transaminases. These studies may point to the possibility that miR-1200 could be a potential drug to treat obesity and atherosclerosis.