Regulation of cardiac metabolism and heart failure by tristetraprolin

 描述（由申请人提供）：心力衰竭（HF）是发达国家的一种主要健康流行病，然而，其基础病理学尚未得到很好的表征。HF的一个标志是心脏细胞中代谢过程的紊乱，包括脂质代谢，心脏组织的主要能量来源。Tristetraprolin（TTP，最初发现受胰岛素调节）是一种串联锌指蛋白，与靶mRNA分子3 '非翻译区（UTR）中的富含AU的元件（ARE）结合，并诱导其降解。TTP敲除（KO）小鼠由于其在TNFα mRNA降解中的作用而表现出全身性炎症，因此很少有研究评估TTP在代谢中的作用。我们最近发现，TTP调节细胞铁通过保存这种金属的必需蛋白质。此外，我们的初步研究表明，TTP调节脂肪酸（FA）代谢，并结合并调节在此过程中的一个关键蛋白，过氧化物酶体增殖物激活受体（PPAR）-α在心肌细胞中的mRNA。该建议的中心假设是TTP通过下调PPARα来调节心脏FA代谢。我们还提出，心脏TTP的删除是保护对HF的发展，由于其对FA代谢的影响。在目的1中，我们将评估TTP是否通过与PPARα mRNA结合并促进其降解来调节心脏FA代谢。我们将评估TTP敲减（KD）的心脏细胞以及来自全局和心脏特异性TTP KO（csTTP-KO）小鼠的心脏中的FA代谢，并将使用TTP/PPARα双KO方法确定这些变化是否通过PPARα。我们还将通过对其3 '-UTR战神、RNA co-IP和mRNA稳定性测定进行缺失研究，评估TTP是否直接调节PPARα。在目标2中，我们将确定TTP是否在HF的发展中起作用，以及这是否依赖于PPARα代谢。我们将对global和csTTP-KO小鼠及其同窝对照进行压力超负荷和冠状动脉结扎，并评估其心脏功能和代谢。

 DESCRIPTION (provided by applicant): Heart failure (HF) is a major health epidemic in developed countries, however, its underlying pathology is not well characterized. A hallmark of HF is derangement of metabolic processes in cardiomocytes, including lipid metabolism, the main energy source of cardiac tissue. Tristetraprolin (TTP, originally discovered to be regulated by insulin) 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. TTP knockout (KO) mice display systemic inflammation due to its role in the degradation of TNFα mRNA, thus very few studies have assessed the role of TTP in metabolism. We recently showed that TTP regulates cellular iron by conserving this metal for essential proteins. In addition, our preliminary studies suggest that TTP regulates fatty acid (FA) metabolism, and binds to and regulates the mRNA of a key protein in this processes, peroxisome proliferator- activated receptor (PPAR)-α in cardiomyocytes. The central hypothesis of this proposal is that TTP regulates cardiac FA metabolism through downregulation of PPARα. We also propose that deletion of cardiac TTP is protective against the development of HF due to its effects on FA metabolism. In Aim 1, we will assess whether TTP regulates cardiac FA metabolism by binding to PPARα mRNA and promoting its degradation. We will assess FA metabolism in cardiac cells with TTP knockdown (KD) and hearts from global and cardiac-specific TTP KO (csTTP-KO) mice, and will determine whether these changes are through PPARα using TTP/PPARα double KO approach. We will also assess whether TTP directly regulates PPARα by performing deletion studies of its 3'-UTR AREs, RNA co-IP, and mRNA stability assays. In Aim 2, we will determine whether TTP plays a role in the development of HF and whether this is dependent on PPARα metabolism. We will subject global and csTTP-KO mice and their littermate controls to pressure overload and coronary ligation and assess their cardiac function and metabolism.