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: 10365412
• 负责人: Hossein Ardehali
• 金额: $ 57.28万
• 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/10365412
• 关键词: 3' Untranslated Regions; Acids; Address; Animal Model; Binding; Binding Proteins; Branched-Chain Amino Acids; Cardiac; Cardiac Myocytes; Catabolism; Cell physiology; Clinical; Co-Immunoprecipitations; Collaborations; Complex; Data; Defect; Developed Countries; 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; Lead; 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; branched chain alpha ketoacid dehydrogenase; cardiogenesis; clinically relevant; constriction; 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; 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)在发达国家是一种主要的健康流行病，然而，其潜在的病理并不是 很好的特点。Tristetraprolin(TTP)是一种串联锌指蛋白，能与体内富AU元素结合。 目的基因的3‘-非翻译区(UTR)，并诱导其降解。全球TTP淘汰赛 (KO)小鼠表现为全身炎症，因为肿瘤坏死因子α基因通常被TTP降解，TTP的缺失 导致肿瘤坏死因子α水平升高。因此，很少有研究评估TTP在新陈代谢中的作用，尽管它 作为胰岛素诱导基因的原始发现，以及将TTP与代谢综合征联系起来的遗传学研究。我们是 解决知识方面的这一根本差距，我们强有力的初步数据表明，TTP开展了关键活动 在心脏代谢和心力衰竭的发展中。具体地说，我们已经证明TTP抑制脂肪酸(FA) 和支链氨基酸(BCAA)代谢(与其对炎症的影响无关)，并减少 这些过程中的关键蛋白，即过氧化物酶体增殖物激活受体-α的基因水平 支链α-酮酸脱氢酶复合体(BCKDC)-E2亚基。中心假说 TTP通过结合和降解FA和BCAA来抑制心脏FA和BCAA的代谢 PPARα和BCKDC-E2mRNAs，而TTP通过损害FA和BCKDC-E2mRNAs而加重心力衰竭的发生 支链氨基酸代谢。在目标1中，我们将评估TTP是否通过与PPARα结合来抑制心脏FA代谢 并促进其降解。我们将通过执行rna来评估ttp是否与PPARαmrna结合。 PPARα3‘-非编码区的共免疫共沉淀和缺失研究我们还将测量FA摄入量 和心脏特异性TTP-KO(csTTP-KO)小鼠心脏的代谢，并将决定这些 改变是通过PPARα使用TTP/PPARα双KO小鼠。在目标2中，我们将确定TTP是否 通过结合和降解BCKDC-E2mRNA来降低支链氨基酸的分解代谢。我们将首先确定 TTP是否通过RNAco-IP与BCKDC-E2mRNA结合及BCKDC-E23‘-UTR缺失研究 阿瑞斯。我们还将测量csTTP-KO小鼠心脏组织中支链氨基酸水平和BCKDC活性。至 证明TTP KO是否通过BCKDC-E2减少支链氨基酸分解代谢，我们将进行 与TTP和BCKDC-E2基因敲除类似的研究。在目标3中，我们将确定TTP是否有害 在压力条件下对心脏的影响，以及这是否取决于FA和支链氨基酸代谢受损。 我们将使csTTP-KO小鼠处于压力超负荷和缺血状态，然后评估它们的心功能和 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 并将csTTP-KO与蛋白磷酸酶2 cm KO小鼠(降低了BCKDC活性)杂交， 并评估心脏对压力的反应。我们还将展示我们开发针对TTP的新药的研究 不会引起炎症，为AIM 3提供潜在的临床意义。这些研究将改善我们的 了解心脏代谢，并可能导致治疗心力衰竭的新途径。