The role of N-6-adenosine and its writer, METTL3, in the cardiac hypertrophic response

项目概要/摘要 心脏肥大是心力衰竭（HF）发生的主要危险因素。肥大的发生是由于 基因和蛋白质表达改变引起的心肌细胞结构和功能变化。多 以前关于HF发病机制的工作主要集中在基因的转录调控上，但是， HF期间的转录调控才刚刚开始探索。最常见的转录后 mRNA修饰，腺苷甲基化（称为N6-甲基腺苷或m6 A），由酶催化 甲基转移酶样3（Methyltransferase-like 3，缩写为L3），最近被鉴定为蛋白质表达的调节因子。我们 目的是确定m6 A和胃L3如何影响心脏肥大及其机制。 我们实验室以前的工作已经证明，无论是获得或失去胃L3的功能，在孤立的 心肌细胞对肥大具有相反的作用，分别增强和抑制肥大。 基于这些观察，我们的主要假设是，肌L3通过以下方式调节心肌细胞肥大： 在心脏应激和心力衰竭期间促进mRNA子集的稳定性。为了验证这一假设，在 目的1我们将心肌细胞特异性心肌L3过表达小鼠以衰老的形式进行心脏应激 和压力超负荷手术这种策略将使我们能够确定胃L3是否可以在体内驱动肥大。 相反，在目标2中，我们将使心肌细胞特异性心肌L3敲除小鼠接受相同形式的心脏刺激。 以确定胃L3是否是心脏肥大发展所必需的。为了更好地理解 在目的3中，我们将确定m6 A在肥大和HF中的具体机制， 修饰影响刺激肥大的分离的心肌细胞中的促肥大mRNA。这项工作 将在Federica Accornero博士的实验室进行，Federica Accornero博士是转录后调控的专家， 心脏肥大，并在心力衰竭领域的领导者Paul Janssen博士的共同监督下， 心肌收缩力随着这个项目的成功完成，我们的研究将阐明未知的 小鼠模型中m6 A和胃L3介导的心脏肥大的机制。我们的长期目标是 能够靶向心脏中的m6 A和胃L3，以改善心脏肥大患者的临床结局 和HF。

Project Summary / Abstract Cardiac hypertrophy is a major risk factor for the development of heart failure (HF). Hypertrophy occurs due to structural and functional changes in cardiomyocytes resulting from altered gene and protein expression. Much of the previous work on HF pathogenesis has focused on transcriptional regulation of genes, but post- transcriptional regulation during HF is only beginning to be explored. The most common post-transcriptional mRNA modification, methylation of adenosines (called N6-methyladenosine or m6A), is catalyzed by the enzyme Methyltransferase-like 3 (METTL3) and has recently been identified as a regulator of protein expression. Our goal is to identify how m6A and METTL3 influence cardiac hypertrophy and the mechanism by which they do so. Our lab's previous work has demonstrated that either gain- or loss-of function of METTL3 in isolated cardiomyocytes have opposing effects on hypertrophy, enhancing and repressing hypertrophy, respectively. Based on these observations, our main hypothesis is that METTL3 modulates cardiomyocyte hypertrophy by promoting the stability of a subset of mRNAs during cardiac stress and heart failure. To test this hypothesis, in Aim 1 we will subject cardiomyocyte-specific METTL3 overexpressing mice to cardiac stress in the form of aging and pressure-overload surgery. This strategy will allow us to determine if METTL3 can drive hypertrophy in vivo. In contrast, in Aim 2 we will subject cardiomyocyte-specific METTL3 knockout mice to the same forms of cardiac stress to determine if METTL3 is necessary for cardiac hypertrophy to develop. To better understand the impact of METTL3 on hypertrophy and HF, in Aim 3 we will determine the specific mechanism by which m6A modifications influence pro-hypertrophic mRNAs in isolated cardiomyocytes stimulated to hypertrophy. This work will be carried out in the laboratory of Dr. Federica Accornero, an expert in post-transcriptional regulation of cardiac hypertrophy, and under the co-supervision of Dr. Paul Janssen, a leader in the field of heart failure and cardiac contractility. With the successful completion of this project, our research will elucidate the unknown mechanism of m6A- and METTL3- mediated cardiac hypertrophy in a mouse model. Our long-term goal is to be able to target m6A and METTL3 in the heart to improve clinical outcomes for patients with cardiac hypertrophy and HF.