Autophagy in Advanced Atherosclerosis

晚期动脉粥样硬化中的自噬

• 批准号: 8208979
• 负责人: Ira A Tabas
• 金额: $ 46.51万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 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/8208979
• 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

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， 破裂和急性血栓形成。坏死斑形成的一个主要过程是内质网（ER） 应激诱导巨噬细胞（Mf）凋亡与这些凋亡的吞噬清除缺陷相结合 Mfs（“红细胞增多症”）。在损伤性Mfs中发生的另一个基本细胞过程是自噬， 细胞为了保护目的降解蛋白质或细胞器。虽然自噬被激活 在动脉粥样硬化期间，这方面的研究主要是描述性的， 假说，机械的洞察力，和分子遗传因果证据在体内。基于已发表的研究， 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存活， 在晚期动脉粥样硬化中出现异常的通路。有趣的是，自噬可能会影响内质网应激- 诱导凋亡和缺陷性红细胞增多。因此，我们建议测试分子细胞 与这些想法相关的机制以及与体内晚期动脉粥样硬化的相关性。在Aim I中，我们将 探索ER应激诱导的自噬最初是通过一种机制来保护的假设， 调节NADPH氧化酶诱导的活性氧（ROS）。我们将测试这一假设和相关的 使用各种工具，包括来自条件基因靶向小鼠的Mfs， 缺乏关键的自噬介质ATG 5。我们还将研究内质网应激诱导细胞凋亡的机制。 自噬以及自噬失败是否先于最终的凋亡。在Aim II中，我们将测试 假设抑制凋亡Mfs中的自噬会抑制其efferocytic清除。我们将使用各种 自噬抑制凋亡细胞的模型，以监测它们被Mf识别和吞噬的能力 并探讨其机制。在Aim III中，我们将使用Atg 5 flox/flox小鼠在体内测试这些想法 与LysMCre和Ldlr-/-小鼠杂交。在其他模型中，LysMCre导致非常有效的floxed缺失。 在损伤Mfs中的基因，并且在初步研究中，我们已经表明来自Atg 5 flox/flox;Lysmcre+/-小鼠的Mfs 抑制自噬，增加ROS，加速凋亡。我们将研究斑块参数 以及与对照组中晚期动脉粥样硬化进展和自噬相关的分子与Mf-ATGF 5- Ldlr-/-背景下的缺陷型小鼠。我们假设Mf-ATG 5缺陷将导致病变， 抑制Mf自噬，增强ROS和凋亡，可能是缺陷性的胞浆细胞增多， 炎症和加速斑块坏死。相反，在Mfs增强自噬的小鼠中， 通过Bcn 1（Beclin-1）的基因过表达，我们预测这些参数的改善， 减少斑块坏死。在这些研究完成后，我们希望有机制和体内 因果关系数据支持自噬在动脉粥样硬化中的保护作用，反过来，这可能表明新的 预防动脉粥样硬化临床进展的治疗策略。