Apolipoprotein AV and intestinal transport

载脂蛋白 AV 和肠道运输

• 批准号: 8914303
• 负责人: PATRICK TSO
• 金额: $ 37.92万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8914303
• 关键词: Affect; Animals; Ants; Apolipoproteins; Apolipoproteins B; Appearance; Bile fluid; Biliary; Blood Circulation; Cholesterol; Chronic; Chylomicrons; Clinical; Clinical Management; Communication; Coronary heart disease; Data; Diabetes Mellitus; Diet; Dose; Emulsions; Endoplasmic Reticulum; Enterocytes; Esterified Fatty Acids; Fatty Acids; Fatty acid glycerol esters; Gastrointestinal Physiology; Gastrointestinal tract structure; Glycerides; Glycerophosphates; Hepatic; Homeostasis; Human; Hypertriglyceridemia; Infusion procedures; Intestines; Knock-out; Knockout Mice; Knowledge; Label; Left; Leucine; Lipids; Lipoproteins; Liver; Lymph; Lymphatic; Measures; Mediating; Membrane; Metabolism; Methionine; Molecular; Monoglycerides; Mus; Obesity; Organ; Outcome; Output; Partial Hepatectomy; Particle Size; Pathway interactions; Phospholipids; Physiology; Plasma; Process; Production; Proteins; Published Comment; Recombinants; Regulation; Research; Research Personnel; Risk Factors; Role; Signal Transduction; Small Intestines; Source; Testing; Time; Transport Vesicles; Triglycerides; Very low density lipoprotein; absorption; apolipoprotein B-48; base; fascinate; feeding; human APOA5 protein; insight; interest; knockout animal; novel; particle; public health relevance; research study; response; therapeutic target; uptake

 DESCRIPTION (provided by applicant): Coronary heart disease, diabetes, and obesity remain major clinical problems worldwide and elevated plasma triglyceride (TG) levels constitute an independent risk factor. Discovered in 2001, apolipoprotein AV (apoAV) is a protein synthesized and secreted by the liver and is found to be inversely proportional to plasma TG levels. Mice and humans lacking functional apoAV have markedly elevated plasma TG while mice with high expression of human apoAV have dramatically decreased plasma TG. Curiously, plasma concentrations of apoAV are extremely low compared with other apolipoproteins such as apoB and apoAI. It has fascinated investigators for years that such a low circulating apolipoprotein can exert such a profound effect on plasma TG. We believe we have some novel insight to this question and this involves apoAV's action on the formation and secretion of chylomicrons (CM) by the enterocytes. Our preliminary data show that: 1) apoAV knockout (KO) animals were significantly more efficient in the absorption and lymphatic transport of both triglyceride (TG) an cholesterol than WT animals; 2) apoAV-KO animals have shorter CM appearance time than WT animals; 3) apoAV-KO animals release more pre-CM transport vesicles (PCTV) from endoplasmic reticulum (ER) than WT animals; 4) apoAV-KO animals secrete more apoB48 (therefore more CM particles since there is one apoB48 per particle) into lymph than WT animals; 5) apoAV is associated with CM in lymph during active fat absorption; and 6) apoAV is present in bile. We hypothesize that apoAV secreted by the liver regulates the intracellular formation and secretion of chylomicrons by the enterocytes and this regulation is mediated via biliary delivery and uptake of apoAV from the intestinal lumen. We will test these hypotheses in two specific aims. AIM 1: To determine the molecular mechanisms underlying the increased lymphatic transport of TG and cholesterol by apoAV-KO mice. There are four subaims to investigate the molecular mechanism of how apoAV modulates the formation and secretion of CM by the small intestine. The role of apoAV in CM and VLDL pathways for the transport of esterified FA will be determined. Taking advantage of our ability to label and isolate intestinal CM, the role of apoAV on CM metabolism will also be studied. AIM 2: Using recombinant apoAV in apoAV-KO animals, we will determine the effect of restoring apoAV in the circulation on intestinal CM transport. We will determine the effect of restoring hepatic production of apoAV to knockout animals (thus restoring both circulating and biliary apoAV) on intestinal CM transport. Lastly, we will determine directly the role of biliary apoAV in the lumen of apoAV-KO animals on lipid and apolipoprotein secretion by the gut, and study the uptake and lymphatic transport of 35S methionine labeled apoAV by the intestine will be studied.

 描述（由适用提供）：冠心病，糖尿病和肥胖症仍然是全球主要的临床问题，血浆甘油三酸酯（TG）水平升高构成了独立的危险因素。载脂蛋白AV（ApoAV）是在2001年发现的，是肝脏合成和分泌的蛋白质，发现与血浆TG水平成反比。缺乏功能性apoaV的小鼠和人类显着升高血浆TG，而人apoav的高表达的小鼠显着改善了血浆TG。奇怪的是，与其他载脂蛋白（如APOB和APOAI）相比，血浆的apoAV浓度极低。多年来，它使研究人员着迷了，这种低循环的载脂蛋白可以对等离子体TG产生如此深远的影响。我们相信我们对这个问题有一些新颖的见解，这涉及Apoav对肠球菌对乳糜微粒（CM）的形成和分泌的行动。我们的初步数据表明：1）Apoav敲除（KO）动物在两种甘油三酸酯（TG）的荒谬和淋巴运输中的效率明显高于WT动物； 2）apoav-ko动物的出现时间比WT动物短； 3）与WT动物相比，Apoav-KO动物从内质网（ER）释放更多的CM前传输蔬菜（PCTV）； 4）apoav-ko动物分泌更多的apob48（以后有更多的cm颗粒，因为每个颗粒有一个APOB48）比WT动物分泌到淋巴上； 5）在活性脂肪损失过程中，apoAV与淋巴中的CM有关； 6）Apoav存在于胆汁中。我们假设由肝脏分泌的apoaV会调节肠上皮细胞对细胞内形成和分泌，并且该调节是通过胆道递送和从肠道内载apoav的吸收来介导的。我们将以两个具体目标来检验这些假设。目标1：确定apoav-ko小鼠TG和胆固醇增加的淋巴运输的基础机制。有四个subiaim可以研究ApoAV如何调节小肠CM的形成和分泌的分子机制。将确定ApoAV在CM和VLDL途径中的作用在酯化FA的运输中。利用我们标记和隔离肠道商业的能力，Apoav在CM代谢中的作用也将是研究。 AIM 2：在Apoav-KO动物中使用重组APOAV，我们将确定恢复循环中Apoav对肠道商业运输的影响。我们将确定恢复ApoAV的肝炎产生以敲除动物（从而恢复循环和胆道apoav）对肠道商业运输的影响。最后，我们将直接确定胆汁apoav在肠道中肠道动物的腔内作用在肠道中的脂质和载脂蛋白分泌中，并研究了由纯种的甲基氨酸标记的apoav的摄取和淋巴运输。