MicroRNAs regulating plasma LDL and HDL

血浆高LDL和低HDL胆固醇水平是心血管疾病的危险因素。微rna 小的非编码内源性RNA（miRs）靶向多个通路并调节生理功能。 由于miR调节不同的生物学途径，我们假设miR存在于自然界中， 可能同时降低LDL和增加HDL。为了发现它们，我们筛选了人类miRs文库， 并鉴定出miR-1200可降低apoB（LDL支架蛋白）和增加apoAI（主要HDL）， 蛋白质）分泌。我们建议找出miR-1200如何降低apoB 分泌，增加apoAI分泌，并增强肝脂肪酸氧化（FAO），以调节血浆 脂蛋白和减少动脉粥样硬化而不引起小鼠脂肪肝。 目的1：探讨小鼠动脉粥样硬化与血浆脂蛋白调节的生理机制。（一） 我们将研究miR-1200对Apoe-/-和Ldlr-/-小鼠血浆脂蛋白和动脉粥样硬化的影响。 小鼠体重增加、VO 2、VCO 2、活动和摄食参数的进一步综合变化 如血浆脂质、脂蛋白、葡萄糖、细胞因子、趋化因子和转氨酶。 miR-1200在不同组织中的积聚及其对靶基因和对照基因、肝细胞和肝脏的影响 将研究脂质、脂质合成和脂肪酸氧化（FAO）。此外，我们将评估是否 miR-1200能够预防喂食高脂肪饮食的野生型小鼠中的饮食诱导的肥胖。(B)我们将评估 假设miR-1200调节肝脏apoB和apoAI分泌以调节血浆LDL， HDL水平。(C)我们将检验miR-1200调节血浆LDL和HDL水平的假设， 肝脏FAO通过调控APOB、BCL 11B和NCOR 1基因表达而发挥作用。(D)我们会问， HDL能够进行胆固醇流出和胆固醇反向转运，并且具有抗炎和抗胆固醇的作用。 氧化剂我们预见增加肝脏miR-1200水平将（1）降低血浆LDL，（2）增加HDL， (3)增加胆固醇逆向转运;（4）增强FAO。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）降低脂质代谢的机制 apoB分泌：我们将（1）测量转染人原代肝细胞的mRNA和蛋白水平 （2）确定miR-1200是否与种子序列相互作用以增强miR-1200或对照miR的表达， apoB mRNA的转录后降解。(B)增加apoAI分泌的机制：我们 假设miR-1200降低BCL 11B表达，抑制子，以增加ApoA转录。 将进行实验以（1）确定BCL 11 B受miR-1200调节，（2）证明如果 BCL 11B抑制apoAI表达，（3）鉴定ApoAI启动子中BCL 11B的结合位点，和 (4)确定在表达miR-1200的细胞中BCL 11B是否与ApoA启动子结合较少。这些 研究将鉴定调节apoAI表达的新机制。(C)提高粮农组织： 我们假设miR-1200通过抑制NCOR 1（一种抑制因子）来增强FAO。我们会证明 miR-1200与NCOR 1 mRNA的3个非编码区相互作用，并增强其降解，从而增加FAO。 此外，我们将证明miR-1200调节NCOR 1与MCAD和CPT 1启动子的结合。 这些研究将提供概念证据，即存在差异调节血浆中的miR 脂蛋白此外，他们将解释参与血浆调节的分子机制 脂蛋白和肝脏FAO。这些研究可能表明，miR-1200可以潜在地降低或预防饮食- 诱导肥胖和减少动脉粥样硬化而不引起脂肪变性和增加血浆 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.