Autophagy in Advanced Atherosclerosis

晚期动脉粥样硬化中的自噬

基本信息

批准号：
8383465
负责人：
Ira A Tabas
金额：
$ 44.28万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-01-01 至 2014-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8383465
关键词：
Acute Affect Apoptosis Apoptotic Area Arterial Fatty Streak Arteries Atherosclerosis Autophagocytosis Blood Platelets Blood Vessels Breeding Cause of Death Cell Survival Cell physiology Cells Clinical Coupled Data Diet Disease Distal Etiology Event Failure Feedback Gene Targeting Generations Genes Genetic Genetic Enhancement Heart Diseases In Vitro Inflammation Investigation Laboratories Lead Learning Lesion Ligands Literature Mediator of activation protein Mitochondria Modeling Molecular Molecular Genetics Monitor Mus Myocardial Infarction NADPH Oxidase Necrosis Organ Organelles Pathway interactions Peptide Hydrolases Physiological Play Process Proteins Publishing Reactive Oxygen Species Role Series Societies Staging Stroke Sudden Death Testing Thrombosis Time Transplantation Vascular blood supply advanced disease arm base cell type cellular transduction endoplasmic reticulum stress feeding in vivo inhibition of autophagy insight interest macrophage novel therapeutics overexpression prevent programs receptor research study response theories tool

项目摘要

A key pathogenic event in the clinical progression of atherosclerosis is plaque necrosis, which triggers plaque disruption and acute thrombosis. A major process in necrotic plaque formation is endoplasmic reticulum (ER) stress-induced macrophage (Mf) apoptosis coupled with defective phagocytic clearance of these apoptotic Mfs ("efferocytosis"). Another fundamental cell process that occurs in lesional Mfs is autophagy, whereby cells degrade proteins or organelles for protective purposes. Although autophagy is known to be activated during atherosclerosis, studies in this area have been largely descriptive and have lacked clear-cut hypotheses, mechanistic insight, and molecular-genetic causal proof in vivo. Based on published studies with other cell types and our own preliminary data, we hypothesize that autophagy is a compensatory cell-survival pathway that goes awry in advanced atherosclerosis. Intriguingly, autophagy may affect both ER stress- induced apoptosis and defective efferocytosis. We therefore propose to test the molecular-cellular mechanisms related to these ideas as well as relevance to advanced atherosclerosis in vivo. In Aim I, we will explore the hypothesis that ER stress-induced autophagy is initially protective through a mechanism that modulates NADPH oxidase-induced reactive oxygen species (ROS). We will test this hypothesis and related ones, and study mechanism, using a variety of tools, including Mfs from conditionally gene-targeted mice lacking the key autophagy mediator ATG5. We will also investigate the mechanisms of ER stress-induced autophagy and whether failure of autophagy precedes eventual apoptosis. In Aim II, we will test the hypothesis that inhibition of autophagy in apoptotic Mfs inhibits their efferocytic clearance. We will use various models of autophagy-inhibited apoptotic cells to monitor their ability to be recognized and engulfed by Mf efferocytes and then to study mechanism. In Aim III, we will test these ideas in vivo by using Atg5flox/flox mice crossed with LysMCre and Ldlr-/- mice. In other models, LysMCre leads to very effective deletion of floxed genes in lesional Mfs, and in preliminary studies we have shown that the Mfs from Atg5flox/flox;Lysmcre+/- mice have inhibited autophagy, increased ROS, and accelerated apoptosis. We will investigate plaque parameters and molecules relevant to advanced atherosclerosis progression and autophagy in control vs. Mf-ATGF5- deficient mice on the Ldlr-/- background. We hypothesize that Mf-ATG5 deficiency will lead to lesions with inhibited Mf autophagy, enhanced ROS and apoptosis, possibly defective efferocytosis and increased inflammation, and accelerated plaque necrosis. Conversely, in mice whose Mfs have enhanced autophagy through genetic overexpression of Bcn1 (Beclin-1), we predict improvement in these parameters and decreased plaque necrosis. Upon the completing of these studies, we hope to have mechanistic and in-vivo causation data supporting a protective role of autophagy in atherosclerosis which, in turn, may suggest novel therapeutic strategies to prevent the clinical progression of atheromata.

动脉粥样硬化临床进展中的一个关键致病事件是斑块坏死，这会触发斑块破坏和急性血栓形成。坏死斑块形成的主要过程是内质网（ER）压力诱导的巨噬细胞（MF）凋亡以及这些凋亡的吞噬清除率有缺陷 MFS（“胞吞作用”）。病变MFS中发生的另一个基本细胞过程是自噬的，细胞降解用于保护目的的蛋白质或细胞器。尽管已知自噬被激活在动脉粥样硬化期间，该领域的研究在很大程度上是描述性的，并且缺乏明确的切割假设，机械洞察力和分子遗传因果在体内证明。根据已发表的研究其他细胞类型和我们自己的初步数据，我们假设自噬是一种补偿性细胞生存在高级动脉粥样硬化中出现问题的途径。有趣的是，自噬可能会影响两个ER应力 - 诱导的凋亡和缺陷的肿瘤病。因此，我们建议测试分子细胞与这些思想相关的机制以及与体内高级动脉粥样硬化的相关性。在目标一世中，我们会探索以下假设：ER应力诱导的自噬最初是通过一种机制来保护的。调节NADPH氧化酶诱导的活性氧（ROS）。我们将检验该假设及相关的假设使用多种工具，包括来自条件基因靶向的小鼠的MF，以及研究机制缺少关键的自噬介质ATG5。我们还将研究ER应力诱导的机制自噬以及自噬的失败是否先于最终凋亡。在AIM II中，我们将测试假设抑制自噬在凋亡MFS中抑制其传染性清除率。我们将使用各种自噬抑制凋亡细胞的模型，以监测其被MF识别和吞噬的能力胚细胞，然后研究机制。在AIM III中，我们将使用ATG5FLOX/FLOX小鼠在体内测试这些想法与lysmcre和ldlr - / - 小鼠交叉。在其他模型中，lysmcre导致非常有效的floxed删除病变MF中的基因和初步研究中，我们表明来自Atg5flox/flox; lysmcre +/-小鼠的MFS 抑制了自噬，ROS增加和加速凋亡。我们将研究牌匾参数和与先进的动脉粥样硬化进展和自噬相关的分子与MF-ATGF5- LDLR - / - 背景上的小鼠不足。我们假设MF-ATG5缺乏将导致病变抑制MF自噬，增强的ROS和凋亡，可能有缺陷的肿瘤病并增加炎症和加速斑块坏死。相反，在MF增强自噬的老鼠中通过BCN1的遗传过表达（Beclin-1），我们预测这些参数的改善和斑块坏死减少。完成这些研究后，我们希望拥有机械和体内因果数据支持自噬在动脉粥样硬化中的保护作用，这反过来可能暗示了新颖的预防动脉瘤的临床进展的治疗策略。