Role of mRNA-binding protein tristetraprolin in cardiac mRNA regulation and the development of heart failure

mRNA结合蛋白tristetraprolin在心脏mRNA调节和心力衰竭发展中的作用

• 批准号: 10544156
• 负责人: Hossein Ardehali
• 金额: $ 57.76万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-15 至 2025-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10544156
• 关键词: 3' Untranslated Regions; Acids; Address; Amino Acids; Animal Model; Binding; Binding Proteins; Branched-Chain Amino Acids; Cardiac; Cardiac Myocytes; Catabolism; Cell physiology; Clinical; Co-Immunoprecipitations; Collaborations; Complex; Data; Defect; Developed Countries; Development; Disease; Elements; Epidemic; Fatty Acids; Genes; Genetic study; Health; Heart; Heart failure; Homeostasis; Human; Impairment; Inflammation; Inflammatory; Insulin; Ischemia; Keto Acids; Knock-out; Knockout Mice; Knowledge; Link; Lipids; Measures; Mediating; Messenger RNA; Metabolic syndrome; Metabolism; Modeling; Mus; Oxidoreductase; PPAR alpha; Pathology; Pathway interactions; Perfusion; Pharmaceutical Preparations; Process; Protein phosphatase; Proteins; RNA; Regulation; Role; Stress; System; TIS11 protein; TNF gene; Testing; Tissues; Zinc Fingers; amino acid metabolism; aorta constriction; branched chain alpha ketoacid dehydrogenase; branched chain fatty acid; clinically relevant; drug discovery; fatty acid metabolism; fatty acid oxidation; heart function; heart metabolism; heart preservation; improved; induced pluripotent stem cell; knock-down; lipid metabolism; mRNA Transcript Degradation; new therapeutic target; novel; oxidation; posttranscriptional; preservation; pressure; response; side effect; systemic inflammatory response; uptake

Heart failure (HF) is a major health epidemic in developed countries, however, its underlying pathology is not well characterized. Tristetraprolin (TTP) is a tandem zinc finger protein that binds to AU-rich elements (ARE) in the 3’-untranslated region (UTR) of target mRNA molecules, and induces their degradation. Global TTP knockout (KO) mice display systemic inflammation, since TNFα mRNA is normally degraded by TTP, and deletion of TTP leads to elevated TNFα levels. Thus, very few studies have assessed the role of TTP in metabolism despite its original discovery as an insulin-inducible gene, and genetic studies linking TTP to metabolic syndrome. We are addressing this fundamental gap in knowledge, and our strong preliminary data suggest critical activities by TTP in cardiac metabolism and the development of HF. Specifically, we have shown that TTP inhibits fatty acid (FA) and branched-chain amino acid (BCAA) metabolism (independent of its effects on inflammation), and reduces the mRNA levels of key proteins in these processes, i.e., peroxisome proliferator-activated receptor (PPAR)-α and branched-chain α–ketoacid acid dehydrogenase complex (BCKDC)-E2 subunits. The central hypothesis of this proposal is that TTP inhibits cardiac FA and BCAA metabolism by binding to and degrading PPARα and BCKDC-E2 mRNAs, and that TTP exacerbates the development of HF by impairing FA and BCAA metabolism. In Aim 1, we will assess whether TTP inhibits cardiac FA metabolism by binding to PPARα mRNA and promoting its degradation. We will assess whether TTP binds to PPARα mRNA by performing RNA co-immunopreciptation (co-IP) and deletion studies of PPARα 3’-UTR AREs. We will also measure FA uptake and metabolism in the hearts from cardiac-specific TTP KO (csTTP-KO) mice, and will determine whether these changes are through PPARα using TTP/PPARα double KO mice. In Aim 2, we will determine whether TTP decreases BCAA catabolism through binding and degradation of BCKDC-E2 mRNA. We will first determine whether TTP binds BCKDC-E2 mRNA by performing RNA co-IP and deletion studies on BCKDC-E2 3’-UTR AREs. We will also measure BCAA levels and BCKDC activity in heart tissue from csTTP-KO mice. To demonstrate whether the reduction in BCAA catabolism with TTP KO is through BCKDC-E2, we will perform similar studies with knockdown of TTP and BCKDC-E2. In Aim 3, we will determine whether TTP has detrimental effects on the heart under stress conditions, and whether this depends upon impaired FA and BCAA metabolism. We will subject csTTP-KO mice to pressure overload and ischemia, then assess their cardiac function and metabolism. To determine the role of PPARα and BCKDC in this process, we will use csTTP/PPARα double KO mice and will cross csTTP-KO with protein phosphatase 2Cm KO mice (which have reduced BCKDC activity), and assess cardiac response to stress. We will also show our studies to develop novel drugs that target TTP without inducing inflammation, providing potential clinical implications for Aim 3. These studies will improve our understanding of cardiac metabolism, and may lead to new avenues for treatment of HF.

心力衰竭（HF）是发达国家的主要健康流行病，然而，其潜在的病理学不是 很好的描述。Tristetraprolin（TTP）是一种串联锌指蛋白，其结合到细胞中的富含AU的元件（ARE）。 靶mRNA分子的3 '-非翻译区（UTR），并诱导其降解。全局TTP敲除 (KO)小鼠显示全身炎症，因为TNFα mRNA通常被TTP降解，而TTP缺失 导致TNFα水平升高。因此，很少有研究评估TTP在代谢中的作用，尽管其 作为胰岛素诱导基因的最初发现，以及将TTP与代谢综合征联系起来的遗传研究。我们 解决这一根本性的知识差距，我们强有力的初步数据表明TTP的关键活动 心脏代谢和心力衰竭的发展。具体来说，我们已经表明，TTP抑制脂肪酸（FA） 和支链氨基酸（BCAA）代谢（独立于其对炎症的影响），并减少 这些过程中关键蛋白的mRNA水平，即，过氧化物酶体增殖物激活受体α 和支链α-酮酸脱氢酶复合物（BCKDC）-E2亚基。核心假设 TTP通过结合并降解FA和BCAA来抑制心脏FA和BCAA代谢， PPARα和BCKDC-E2 mRNA，TTP通过损害FA和 支链氨基酸代谢。在目的1中，我们将评估TTP是否通过与PPARα结合来抑制心脏FA代谢 mRNA并促进其降解。我们将评估TTP是否与PPARα mRNA结合， 免疫共沉淀（co-IP）和PPARα 3 '-UTR战神的缺失研究。我们还将测量FA摄取 和代谢的心脏特异性TTP KO（csTTP-KO）小鼠，并将确定是否这些 使用TTP/PPARα双基因敲除小鼠通过PPARα表达的变化。在目标2中，我们将确定TTP是否 通过结合和降解BCKDC-E2 mRNA降低BCAA催化剂。我们将首先确定 通过对BCKDC-E2 3 '-UTR进行RNA co-IP和缺失研究，确定TTP是否与BCKDC-E2 mRNA结合 战神。我们还将测量来自csTTP-KO小鼠的心脏组织中的BCAA水平和BCKDC活性。到 为了证明TTP KO是否通过BCKDC-E2减少BCAA催化剂，我们将进行 用TTP和BCKDC-E2的敲低进行类似的研究。在目标3中，我们将确定TTP是否具有有害的 压力条件下对心脏的影响，以及这是否取决于受损的FA和BCAA代谢。 我们将使csTTP-KO小鼠经受压力超负荷和缺血，然后评估它们的心脏功能， 新陈代谢.为了确定PPARα和BCKDC在这一过程中的作用，我们将使用csTTP/PPARα双KO 将csTTP-KO与蛋白磷酸酶2Cm KO小鼠（其具有降低的BCKDC活性）杂交， 评估心脏对压力的反应我们还将展示我们的研究，以开发针对TTP的新药 而不诱导炎症，为目标3提供了潜在的临床意义。这些研究将改善我们的 了解心脏代谢，并可能导致治疗HF的新途径。