PCSK9-A novel target for the treatment of myocardial ischemia

PCSK9-治疗心肌缺血的新靶点

• 批准号: 9896662
• 负责人: JAWAHAR L MEHTA
• 金额: --
• 依托单位: CENTRAL ARKANSAS VETERANS HLTHCARE SYS
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9896662
• 关键词: Applications Grants; Area; Autophagocytosis; Binding; Cardiac; Cardiac Myocytes; Cardiovascular system; Chronic; Collagen; Complex; Coronary artery; DNA Damage; Echocardiography; Elderly; Enzymes; Event; Exhibits; Exposure to; Fibroblasts; Generations; Genes; Heart; Histology; Hypoxia; Immunohistochemistry; In Vitro; Infarction; Infiltration; Inflammation; Inflammatory; Interleukin-1 beta; Ischemia; Kidney; LDL Cholesterol Lipoproteins; Laboratories; Left; Leukocytes; Ligation; Liver; Low Density Lipoprotein Receptor; Low-Density Lipoproteins; Measures; Mitochondria; Mitochondrial DNA; Modeling; Molecular Biology; Mus; Myocardial; Myocardial Ischemia; Patients; Proprotein Convertases; Role; Signal Transduction; Small Intestines; Subtilisins; TNF gene; Testing; Time; Tissues; Transgenic Mice; Veterans; Work; atherogenesis; base; design; heart function; in vivo; inhibitor/antagonist; innovation; ischemic injury; migration; monocyte; mouse model; myocardial infarct sizing; neutrophil; novel; receptor

Mainly expressed in liver, kidney and small intestine, the enzyme proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to the low-density lipoprotein-cholesterol receptor (LDLr), and causes degradation of LDLs. Although not proven, it has been suggested that these agents may reduce cardiovascular events. Recent work from our group shows that besides the liver, kidney and small intestine, cardiomyocytes also express PCSK9. The secretion of PCSK9 increases during ischemia by >10 fold. PCSK9 expression is maximal in the region adjacent to the infarcted area (border zone). Cardiomyocytes in the border zone also exhibit intense inflammation and autophagy. Other recent work in our laboratory suggests that PCSK9 secretion may regulate inflammation and autophagy. Based on these new findings, we wish to critically examine the role of myocardial PCSK9 in ischemia, an issue not previously studied. The 2 major aims of the grant proposal are: Aim 1: To examine the role of PCSK9 in the determination of infarct size and cardiac function. Approach: These studies will be done in a mouse model of permanent left coronary artery (LCA)] ligation. Studies will be performed in wild-type C57BL/6 and PCSK-/- mice. PCSK9 expression, inflammation (with emphasis on infiltration of tissue injurious CCR2+Ly6Chigh monocytes and neutrophils) and autophagy along with infarct size and cardiac function (echocardiography) will be measured at different time points. Molecular biology studies, histology and immunohistochemistry will be performed in different regions of the heart. To determine the role of inflammation in PCSK9 release and its effects, parallel studies will be performed in TNFα-/- mice and IL-1β-/- mice. Lastly, to confirm the role of PCSK9 in ischemic injury, studies will be performed in mice with selective PCSK9 deletion in the heart. Impact: These in vivo studies will clarify the role of PCSK9 in determination of infarct size and cardiac function/remodeling. Further, these studies will reveal the role of inflammation in the induction of PCSK9 secretion during chronic ischemia. Aim 2: To examine mechanisms underlying PCSK9’s effects on the heart during ischemia. Approach: To study the complex interaction between PCSK9, inflammation and autophagy during ischemia, primary mouse cardiomyocytes will be exposed to varying periods of hypoxia (in vitro studies). We will study the impact of hypoxia-induced PCSK9 release on leukocyte migration, mitochondrial ROS generation and mitochondrial DNA damage and autophagy signals. Impact of PCSK9 (along with inflammatory signals) on the generation of collagen (in fibroblasts) will also be studied. Impact: These studies will reveal the mechanisms by which PCSK9 influences inflammation and autophagy, and subsequently cardiac remodeling during chronic myocardial ischemia. Innovation and Significance: PCSK9 inhibition by lowering LDL-C may significantly influences atherogenesis and cardiovascular events. We believe that the proposed studies will test a novel hypothesis that it is the local release of PCSK9 that regulates pro-inflammatory and autophagy signals and collagen generation (cardiac remodeling). Its inhibition may modulate myocardial infarct size and subsequent cardiac modeling. The results of these innovative studies may impact the lives of millions of patients (and elderly veterans) who suffer from chronic myocardial ischemia and may be treated with PCSK9 inhibitors.

主要在肝脏，肾脏和小肠中表达，酶蛋白转化酶枯草酶/凯克森蛋白 9型（PCSK9）与低密度脂蛋白 - 胆固醇受体（LDLR）结合，并导致降解 尽管未经证明，但有人建议这些药物可能会减少心血管 事件。我们小组的最新工作表明，除了肝脏，肾脏和小肠外， 心肌细胞也表达PCSK9。缺血期间PCSK9的分泌增加> 10倍。 PCSK9表达在梗塞区域（边界区）附近的区域中最大。心肌细胞 在边界区域还表现出强烈的炎症和自噬。我们最近的其他工作 实验室建议PCSK9分泌可以调节注射和自噬。基于这些 新发现，我们希望批判性地研究心肌PCSK9在缺血中的作用，这不是一个问题 以前研究。赠款提案的两个主要目标是： 目的1：检查PCSK9在确定基础设施大小和心脏功能中的作用。 方法：这些研究将在永久左冠状动脉（LCA）的小鼠模型中进行。 结扎。研究将在野生型C57BL/6和PCSK - / - 小鼠中进行。 PCSK9表达式， 炎症（重点是组织有害CCR2+Ly6chigh单核细胞和 中性粒细胞）和自噬以及基础设施大小和心脏功能（超声心动图）将是 在不同的时间点测量。分子生物学研究，组织学和免疫组织化学将 在心脏的不同地区进行。确定炎症在PCSK9释放中的作用 及其效果，将在TNFα - / - 小鼠和IL-1β-/ - 小鼠中进行平行研究。最后，确认 PCSK9在缺血性损伤中的作用，将在具有选择性PCSK9缺失的小鼠中进行研究 心。影响：这些体内研究将阐明PCSK9在确定梗塞大小和 心脏功能/重塑。此外，这些研究将揭示炎症在诱导中的作用 慢性缺血期间的PCSK9分泌。 目标2：检查PCSK9在缺血期间对心脏的影响的机制。方法： 研究缺血期间PCSK9，炎症和自噬之间的复杂相互作用 小鼠心肌细胞将暴露于低氧时期（体外研究）。我们将研究 缺氧引起的PCSK9释放对白细胞迁移，线粒体ROS的产生和 线粒体DNA损伤和自噬信号。 PCSK9的影响（以及炎症信号） 还将研究胶原蛋白的产生（成纤维细胞）。影响：这些研究将揭示 PCSK9影响注射和自噬的机制，随后心脏 慢性心肌缺血期间的重塑。 创新和意义：通过降低LDL-C抑制PCSK9可能会显着影响 动脉粥样硬化和心血管事件。我们认为拟议的研究将测试一本小说 假设是PCSK9的本地发布来调节促炎和自噬信号 和胶原蛋白（心脏重塑）。它的抑制作用可能调节心肌梗塞的大小和 随后的心脏建模。这些创新研究的结果可能会影响数百万的生活 患有慢性心肌缺血的患者（和老年退伍军人），可能会接受 PCSK9抑制剂。