Avoiding toxicity associated with MTP ablation

避免与 MTP 消融相关的毒性

基本信息

批准号：
8448007
负责人：
M Mahmood Hussain
金额：
$ 51.23万
依托单位：
SUNY DOWNSTATE MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-02-01 至 2016-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8448007
关键词：
Ablation Accounting Adverse effects Advocate Agonist Alanine Transaminase Anabolism Apolipoproteins B Apoptosis Aspartate Transaminase Assimilations Atherosclerosis Canis familiaris Cardiovascular Diseases Cardiovascular system Catabolism Cell Death Chemicals Cholesterol Cholesterol Esters Coronary Data Diabetes Mellitus Diet Disease Endoplasmic Reticulum Enzymes Event Excision Familial Combined Hyperlipidemia Familial Hypercholesterolemia Fatty Acids Fatty acid glycerol esters Future Gene Deletion Genes Genetic Golgi Apparatus Health Hepatic Hepatocyte Hyperlipidemia In Vitro Induction of Apoptosis Intestines Lead Link Lipids Lipoproteins Liver Lovastatin MAPK8 gene Measurement Messenger RNA Metabolic Metabolic Diseases Metabolic syndrome Microsomes Modality Molecular Molecular Chaperones Mus Obesity Olive oil preparation Operative Surgical Procedures Outcome Oxidoreductase Pathway interactions Patients Peroxisome Proliferator-Activated Receptors Pharmaceutical Preparations Pharmacologic Substance Phospholipids Plasma Population Process Production Protein Inhibition Protein Isoforms Proteins Research Research Personnel Risk Factors Role Solutions Structural Protein Testing Thapsigargin Therapeutic Intervention Therapeutic Uses Toxic effect Transaminases Triglycerides Tunicamycin activating transcription factor bariatric surgery base biological adaptation to stress caspase 12 cholesterol biosynthesis endoplasmic reticulum stress fatty acid oxidation feeding genetic inhibitor in vitro activity inhibitor/antagonist innovation liver injury liver transplantation microsomal triglyceride transfer protein novel novel strategies novel therapeutics public health relevance research study success

项目摘要

DESCRIPTION (provided by applicant): High plasma lipids and lipoproteins are risk factors for various cardiovascular and metabolic disorders. An approach to lower plasma lipids is to inhibit apoB-lipoprotein biosynthesis, a process critically dependent on an endoplasmic reticulum (ER) resident chaperone, microsomal triglyceride transfer protein (MTP). MTP inhibitors decrease apoB-lipoprotein secretion and lower plasma cholesterol. However, they increase plasma aminotransferases, such as ALT and AST, indicating liver injury. We hypothesize that increases in plasma hepatic enzymes associated with MTP inhibition are due to increases in microsomal free cholesterol, induction of ER stress and cell death. We further hypothesize that reducing cellular free cholesterol along with MTP inhibition might reduce hyperlipidemias and avoiding toxicities associated with MTP antagonists. In the first aim, Alb-Cre-MTPfl/fl or MTPfl/fl mice will be fed T-0901317, a LXR agonist to induce free cholesterol efflux; lovastatin, a HMG Co-A reductase antagonist to inhibit cellular cholesterol biosynthesis; or WY14643, a PPAR1 agonist to enhance 2-oxidation of fatty acids, for 3 or 24 weeks. In another group, &-3 fatty acids, PPAR1/4 agonists, will be injected intraperitoneally to reduce hepatic triglyceride and free cholesterol. In addition, Alb-Cre-MTPfl/fl mice will be fed a western diet and then treated with T-0901317, lovastatin, WY14643, or &-3 fatty acids. Experiments will then be performed in C57Bl/6J mice fed a western diet and fed daily with MTP inhibitors. Additionally, they will be fed olive oil alone or with other compounds described above to determine if toxicities associated with MTP inhibitors can be avoided by these treatments. Outcome measurements will involve changes in apoB-lipoproteins and hepatic enzymes in the plasma; hepatic triglycerides, esterified cholesterol, and free cholesterol; quantification of candidate mRNAs and proteins involved in cholesterol and triglyceride biosynthesis, ER stress, as well as AST/ALT isoforms. These studies will show that toxicities associated with MTP inhibition can be avoided by reducing hepatic free cholesterol. The second aim is to test the hypothesis that release of hepatic enzymes in the plasma is due to the induction of the ER stress and apoptosis. We will first demonstrate that MTP inhibition increases microsomal free cholesterol. Second, we will identify the ER stress pathways activated by MTP ablation/inhibition. Third, we will establish that MTP inhibition induces apoptosis. Fourth, a link between the ER stress and induction of apoptosis will be established. Fifth, importance of the ER stress pathways will be substantiated using ATF6-/-, CHOP-/- and Alb-Cre-Ire11fl/fl mice fed MTP inhibitors. Sixth, we will determine if induction of ER stress by tunicamycin increases plasma AST/ALT levels. At the completion of these studies, we will find out molecular mechanisms responsible for unwanted side effects associated with MTP therapy and suggest solutions to avoid these toxicities. These studies may lead to new therapeutic modalities for the treatment of various hyperlipidemias and have immediate potential for translational use.

描述（由申请人提供）：高血浆脂质和脂蛋白是各种心血管和代谢疾病的危险因素。较低血浆脂质的一种方法是抑制APOB-脂蛋白生物合成，这是一种关键取决于内质网（ER）常驻伴侣伴侣，微胶质甘油三酸酯转移蛋白（MTP）的过程。 MTP抑制剂降低APOB脂蛋白的分泌和降低血浆胆固醇。但是，它们增加了血浆氨基转移酶，例如ALT和AST，表明肝损伤。我们假设与MTP抑制相关的血浆肝酶增加是由于微粒体胆固醇的增加，ER应激和细胞死亡的诱导。我们进一步假设，降低无细胞胆固醇以及MTP抑制作用可能会降低高脂性血症并避免与MTP拮抗剂相关的毒性。在第一个目标中，Alb-Cre-MTPFL/FL或MTPFL/FL小鼠将被喂食T-0901317，这是一种LXR激动剂，可诱导自由胆固醇外排； Lovastatin，一种HMG Co-A还原酶拮抗剂可抑制细胞胆固醇生物合成；或WY14643，一种PPAR1激动剂，可增强脂肪酸的2氧化3或24周。在另一组中，＆-3脂肪酸（PPAR1/4激动剂）将被腹膜内注射以减少肝甘油三酸酯和游离胆固醇。此外，Alb-Cre-MTPFL/FL小鼠将喂食西方饮食，然后用T-0901317，Lovastatin，WY14643或＆-3脂肪酸处理。然后，将在喂食西方饮食的C57BL/6J小鼠中进行实验，并每天用MTP抑制剂喂食。此外，它们将单独或与上述其他化合物一起喂食，以确定这些治疗方法是否可以避免与MTP抑制剂相关的毒性。结果测量将涉及血浆中APOB脂蛋白和肝酶的变化；肝甘油三酸酯，酯化胆固醇和自由胆固醇；量化参与胆固醇和甘油三酸酯生物合成，ER应激以及AST/ALT同工型的候选mRNA和蛋白质。这些研究将表明，可以通过减少无肝胆固醇来避免与MTP抑制作用相关的毒性。第二个目的是检验以下假设：血浆中肝酶的释放是由于诱导ER应激和凋亡的诱导。我们首先证明MTP抑制会增加无微粒体胆固醇。其次，我们将确定通过MTP消融/抑制激活的ER应力途径。第三，我们将确定MTP抑制会诱导凋亡。第四，将建立ER应力与诱导凋亡之间的联系。第五，使用ATF6 - / - ，Chop - / - 和Alb-Cre-Cre-Cre11fl/FL小鼠喂食MTP抑制剂的第五，将证实ER应力途径的重要性。第六，我们将确定衣霉素诱导ER应激是否会增加血浆AST/ALT水平。这些研究完成后，我们将发现负责与MTP治疗相关的不良副作用的分子机制，并建议避免这些毒性的解决方案。这些研究可能会导致新的治疗方式，以治疗各种高脂症，并具有直接的翻译潜力。