RNA-Mediated Inter-Organelle Communication in Atherosclerosis

项目摘要 缺血性心血管疾病(CVD)是由动脉粥样硬化引起的，动脉粥样硬化是一种脂质驱动的炎症性疾病 影响动脉，这可能进展为脆弱的斑块和血栓闭塞。精准的 将营养过剩和高脂血症与免疫激活联系起来的分子机制仍然难以捉摸 这些机制的发现可能会导致新的心血管疾病治疗方法。一个重要的入门读物 血脂异常的炎症是指慢性代谢超负荷和合成代谢受损。 分解代谢细胞器。减少细胞器应激可减轻胰岛素抵抗和动脉粥样硬化。 最近，我们发现肌醇需要酶-1(IRE1)的小分子抑制剂，它是一种近端的内质网 压力感应器，对抗动脉粥样硬化进展。ER膜也可作为成核位置 对于RNA诱导的沉默复合体(RISC)，我们有一个惊人的发现，IRE1激酶 磷酸化双链RNA结合蛋白，蛋白激酶R的蛋白激活剂 (PACT)，与RISC相关联。我们发现，脂质应激诱导IRE1磷酸化PACT，这是 抑制线粒体生物发生(有丝分裂生物发生)，部分是通过控制miRNA(MiR)-181c。 动态平衡机制，如有丝分裂(去除)或有丝分裂生物发生(以补充)功能障碍 线粒体可以对抗炎症，也可以在动脉粥样硬化斑块细胞中发挥作用。异常激活 脂质抑制IRE1-PACT信号转导有丝分裂生物并促进线粒体氧化应激 炎症，表明抑制这一病理信号可以对抗动脉粥样硬化。协定 位于人类2号染色体上与早发冠状动脉疾病有关的一个基因座附近， 血浆高密度脂蛋白胆固醇水平。PACT的表达在动脉粥样硬化进展过程中被诱导，并在 在小鼠体内出现退化。我们假设抑制IRE1-PACT信号将促进有丝分裂生物发生 并能对抗炎症和动脉粥样硬化。我们将阐明PACT如何通过以下方式调节有丝分裂生物发生 发现PACT的miR靶点(S)及其与有丝分裂生物发生调控相关的RNA靶。我们 已发现的miR-181c是这些阻止有丝分裂生物发生的PACT靶点之一。我们将直接调查 PACT和miR-181c在高脂血症诱导的有丝分裂、炎症和动脉粥样硬化中的作用 在活体内。根据已发现的目标(针对miR-181c和其他目标)，我们将制定更具体的 靶向治疗方法(使用锁定核酸靶点阻滞剂)消融miR和靶点 动脉粥样硬化小鼠之间的相互作用。这些研究的成功完成将有助于确定 内质网和线粒体之间前所未有的免疫代谢串扰机制 高脂血症可促进MOX应激、炎症和动脉粥样硬化。理解内在的 在动脉粥样硬化形成过程中，这种RNA介导的细胞器间通讯的运行可能为 为针对心血管疾病中这种特定免疫代谢串扰的新治疗方法开辟道路。

PROJECT ABSTRACT Ischemic cardiovascular disease (CVD) is caused by atherosclerosis, a lipid-driven inflammatory disease affecting the arteries, which can progress into vulnerable plaques and thrombotic occlusion. The precise molecular mechanisms linking nutrient excess and hyperlipidemia to immune activation remains elusive and the discovery of these mechanisms could lead to novel CVD therapeutics. An important primer for inflammation in dyslipidemia is the chronic metabolic overloading and impairment of anabolic and catabolic organelles. Reduction of organelle stress alleviates insulin resistance and atherosclerosis. Recently, we showed that small molecule inhibitors of Inositol-requiring enzyme -1 (IRE1), a proximal ER stress sensor, counteract atherosclerosis progression. The ER membranes also serve as a nucleation site for RNA-induced silencing complex (RISC), and we made the striking discovery that IRE1 kinase phosphorylates the double stranded RNA-binding protein, the protein activator of the protein kinase R (PACT), that associates with RISC. We found lipid stress induces IRE1 to phosphorylate PACT, which suppresses mitochondrial biogenesis (mito-biogenesis), in part by controlling a miRNA (miR)-181c. Homeostatic mechanisms such as mitophagy (to remove) or mito-biogenesis (to replenish) the malfunctioning mitochondria can counteract inflammation and also operate in atherosclerotic plaque cells. Aberrant activation of IRE1-PACT signaling by lipids block mito-biogenesis and propagate mitochondrial oxidative (MOX) stress and inflammation, indicating inhibition of this pathological signaling could counteract atherosclerosis. PACT is proximal to a locus on human chromosome 2 that is linked to premature coronary artery disease and plasma HDL-C levels. PACT expression is induced during atherosclerosis progression and reduced during regression in mice. We hypothesize that suppressing IRE1-PACT signaling will promote mito-biogenesis and counteract inflammation and atherosclerosis. We will elucidate how PACT regulates mito-biogenesis by discovering PACT’s miR target(s) and their RNA targets that are relevant to mito-biogenesis regulation. We discovered miR-181c is one of these PACT targets that blocks mito-biogenesis. We will directly investigate the impact of PACT and miR-181c on hyperlipidemia-induced mito-biogenesis, inflammation and atherosclerosis in vivo. Based on the discovered targets (for miR-181c and others) we will develop a more specific therapeutic targeting approach (using Locked Nucleic Acid-Target-Site Blockers) to ablate miR and target interaction in atherosclerotic mice. The successful completion of these studies will help define an unprecedented mechanism of immune-metabolic crosstalk between ER and mitochondria by which hyperlipidemia can promote MOX stress, inflammation and atherosclerosis. Understanding the intrinsic operation of this RNA-mediated inter-organelle communication during atherogenesis could pave the way for novel therapeutic approaches targeting this specific immune-metabolic cross talk in CVD.