Sptlc3-derived sphingolipids in cardiomyocyte death in ischemia

Sptlc3衍生的鞘脂在缺血心肌细胞死亡中的作用

基本信息

批准号：
10543839
负责人：
Anna Philip Kovilakath
金额：
$ 4.06万
依托单位：
VIRGINIA COMMONWEALTH UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-01-15 至 2024-01-14
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10543839
关键词：
Affect Anabolism Anterior Descending Coronary Artery Apoptosis Apoptotic Autophagocytosis Binding Biological Brain Hypoxia-Ischemia Cardiac Cardiac Myocytes Cause of Death Cell Death Cell Death Induction Cell Nucleus Ceramides Cessation of life Coenzyme A Complex Cytoplasm Data Dihydrosphingosine Enzymes Event Foundations General Population Goals Heart Heart failure Human Induction of Apoptosis Ischemia Knockout Mice Left Ligation Lipids Longevity Mediating Metabolism Mitochondria Modeling Multienzyme Complexes Mus Myocardial Myocardial Ischemia Palmitoyl Coenzyme A Parkin Pathology Pathway interactions Patient-Focused Outcomes Patients Phosphorylation Play Prevention Proteins Publications Reaction Research Role Sphingolipids Stress Structure TP53 gene Testing Therapeutic Tissues candidate marker cardiovascular health cohort dihydrosphingosine 1-phosphate improved in vivo innovation insight ischemic cardiomyopathy ischemic injury knock-down mitochondrial dysfunction mouse model myocardial injury novel overexpression protein protein interaction serine palmitoyltransferase sphingosine 1-phosphate therapeutic evaluation therapeutic target

项目摘要

Project Summary Ischemic cardiomyopathy is the leading cause of death in the world and affects approximately 1% to 2% of the general population. Sphingolipids including ceramides and sphingosine-1-phosphate have been demonstrated to play roles in myocardial injury. Previous research from the lab showed that SPTLC3-derived sphingolipids comprise greater than 1/3rd the myocardial sphingolipid pool, a previously underappreciated group of sphingolipids. SPTLC3, a recently identified subunit of the serine palmitoyltransferase (SPT) enzyme, along with SPTLC1, synthesizes the SPTLC3-derived or non-canonical sphingolipids, whereas SPTLC2 with SPTLC1 synthesizes canonical sphingolipids. Over-abundance of SPTLC3-derived sphingolipids has been associated with increased apoptosis in cardiomyocytes and other heart pathologies. Little is known of the induction of the programmed cell death pathways by these particular sphingolipids. Interestingly, I found that SPTLC3 and derived sphingolipids showed robust induction in human and mouse ventricle ischemic tissue as compared to complete absence of SPTLC3 in the non-ischemic control tissues. Based on my preliminary results, I hypothesize that induction of SPTLC3 increases d16-DHS1P which in turn promotes formation of an ATG7/P53/Parkin complex by direct binding. This leads to inhibition of Parkin- mediated mitophagy thereby promoting mitochondria-dependent cell death. Our preliminary data support that SPTLC3-derived sphingolipids induce formation of a novel complex between ATG7, P53, and Parkin, and we propose complex formation of this complex mediates apoptosis. Therefore, to test this hypothesis we will overexpress and/or knockdown SPTLC3 and determine protein-lipid and protein-protein interactions and whether this complex regulates mitophagy and/or apoptotic pathways. Second, We hypothesize that cardiomyocyte specific Sptlc3 knockout mice will show improved cardiovascular health and subsequent increased longevity in ischemia as compared to their control cohorts. To test our hypothesis, we recently developed a cardiomyocyte specific Sptlc3 null mouse (cSptlc3 KO) line, which to our knowledge is the first of its kind. We will be performing permanent left anterior descending (LAD) coronary artery ligation in the cardiomyocyte specific Sptlc3 null mouse (cSptlc3 KO). We will then determine the impact of SPTLC3 depletion on cardiac sphingolipid profiles, mitophagy/apoptosis, and cardiac structure/function in ischemia including adverse remodeling. Understanding the biological activities of the SPTLC3-derived sphingolipids will provide insights and establish the role of these sphingolipids in cardiac ischemia. This proposal will lay the foundation for further research on potential targeting of the pathway as an innovative therapeutic option to circumvent ischemia leading to heart failure and improve patient outcome.

项目概要缺血性心肌病是世界上死亡的主要原因，影响约 1% 至 2% 普通民众的。鞘脂包括神经酰胺和 1-磷酸鞘氨醇已被证明在心肌损伤中发挥作用。实验室之前的研究表明 SPTLC3 衍生鞘脂占心肌鞘脂库的 1/3 以上，这是一个以前被低估的群体鞘脂。 SPTLC3 是最近发现的丝氨酸棕榈酰转移酶 (SPT) 的一个亚基，与 SPTLC1 一起合成 SPTLC3 衍生的或非规范的鞘脂，而 SPTLC2 与 SPTLC1 一起合成合成典型的鞘脂。 SPTLC3 衍生的鞘脂过多与心肌细胞凋亡和其他心脏病理增加。人们对感应的知之甚少这些特定鞘脂的程序性细胞死亡途径。有趣的是，我发现 SPTLC3 和与非缺血对照组织中完全缺乏 SPTLC3。根据我的初步结果，我假设 SPTLC3 的诱导会增加 d16-DHS1P，这在转角通过直接结合促进 ATG7/P53/Parkin 复合物的形成。这导致 Parkin- 的抑制介导的线粒体自噬，从而促进线粒体依赖性细胞死亡。我们的初步数据支持这一点 SPTLC3 衍生的鞘脂诱导 ATG7、P53 和 Parkin 之间新型复合物的形成，我们提出该复合物的复合物形成介导细胞凋亡。因此，为了检验这个假设，我们将过表达和/或敲低 SPTLC3 并确定蛋白质-脂质和蛋白质-蛋白质相互作用，该复合物是否调节线粒体自噬和/或细胞凋亡途径。其次，我们假设心肌细胞特异性 Sptlc3 敲除小鼠将表现出改善与对照组相比，心血管健康和随后的缺血寿命延长。到检验我们的假设，我们最近开发了心肌细胞特异性 Sptlc3 缺失小鼠 (cSptlc3 KO) 系，该系据我们所知，这是同类中的第一个。我们将进行永久性左前降支 (LAD) 冠状动脉手术心肌细胞特异性 Sptlc3 缺失小鼠 (cSptlc3 KO) 的动脉结扎。然后我们将确定影响 SPTLC3 耗竭对心脏鞘脂谱、线粒体自噬/细胞凋亡和心脏结构/功能的影响缺血，包括不良重塑。了解 SPTLC3 衍生的鞘脂的生物活性将提供见解和确定这些鞘脂在心脏缺血中的作用。该提案将为进一步的研究该途径的潜在靶向作为规避缺血导致的创新治疗选择心力衰竭并改善患者预后。