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心肌梗死导致心肌细胞（CM）的不可逆损失，并经常导致心力衰竭。到 为了替代丢失的细胞，我们确定了一种细胞周期调节剂的组合，它可以诱导成体细胞稳定的胞质分裂。 有丝分裂后的细胞细胞周期蛋白依赖性激酶1（CDK 1）、CDK 4、细胞周期蛋白B1和细胞周期蛋白D1的过表达（参见 至4F）促进有丝分裂后小鼠、大鼠和人心肌细胞的细胞分裂。的高效率 这种诱导心肌细胞更新的方法为理解所涉及的机制提供了新的机会 在心肌细胞增殖中。与这一发现相关的最有趣的发现之一是， 代谢重编程和心肌细胞增殖之间的联系。尽管在增殖细胞中 代谢变化和细胞增殖之间存在很强的相关性，但仍不清楚代谢如何影响细胞增殖。 影响心肌细胞的增殖潜力。在过去的两年里，与希尔博士的合作 组，我已经产生了初步的数据表明，心肌细胞增殖与 在能量代谢方面有显著的重组在从谱系追踪中分离的增殖心肌细胞中 在MADM小鼠中，RNA-seq数据表明脂肪酸氧化基因的显著下调和 生物合成途径酶表达;在人iPSC衍生的心肌细胞（hiPSC-CM）中，4F表达 减少线粒体呼吸和分解代谢活动。使用稳定同位素分辨代谢组学 （SIRM），我们证明了4F感染的hiPS-CM在13 C标记的中间体或 氨基己糖生物合成途径（HBP）、丝氨酸生物合成途径（SBP）和戊糖的终产物 磷酸途径（PPP）。与这些发现一致，我们的研究结果还表明，增加碳 通过过表达磷酸烯醇式丙酮酸羧激酶（PCK 1或 PCK 2）增强心肌细胞增殖的能力。这些数据表明，较高的生物合成 心肌细胞增殖可能需要途径通量。根据这些结果，我们提出了一般的 假设葡萄糖代谢辅助生物合成途径的激活是 心肌细胞增殖我们认为，更高的生物合成途径通量是必需的积木 合成，并可能是重要的调节促增殖基因程序。在这个项目中，我们将 描述每种生物合成途径在影响心肌细胞增殖中的重要性。首先利用 通过药理学和基于病毒的方法，我们将确定HBP、SBP和 PPP途径与肌细胞增殖。此外，我们将研究增加碳通量的影响 在生物合成途径中通过PCK 1或PCK 2的过表达对心脏功能和体内修复的影响。的 本项目的目标是：具体目标1：阐明心肌细胞各生物合成途径的作用 增殖具体目标2：研究增加生物合成途径中碳通量的功能功效 在体内心脏修复上的应用

Myocardial infarction causes irreversible loss of cardiomyocytes (CMs) and often leads to heart failure. To replace the lost cells, we identified a combination of cell-cycle regulators that induces stable cytokinesis in adult post-mitotic cells. Overexpression of cyclin-dependent kinase 1 (CDK1), CDK4, cyclin B1, and cyclin D1 (referred to as 4F) promotes cell division in post-mitotic mouse, rat, and human cardiomyocytes. The high efficiency of this protocol in inducing myocyte renewal provides new opportunities for understanding the mechanisms involved in cardiomyocyte proliferation. One of the most interesting findings related to this discovery was the confirmation of a link between metabolic reprogramming and cardiomyocyte proliferation. Although in proliferating cells there is a strong correlation between metabolic changes and cellular proliferation, it remains unclear how metabolism influences the proliferative potential of cardiomyocytes. During the past 2 years, in collaboration with Dr. Hill’s group, I have generated preliminary data which indicate that cardiomyocyte proliferation is associated with marked reprogramming in energy metabolism. In proliferating cardiomyocytes isolated from lineage tracing (MADM) mice, RNA-seq data indicate profound downregulation of fatty acid oxidation genes and upregulation of biosynthetic pathway enzyme expression; in human iPSC-derived cardiomyocytes (hiPSC-CMs), 4F expression decreases mitochondrial respiration and catabolic activities. Using stable isotope-resolved metabolomics (SIRM), we demonstrate that 4F-infected hiPS-CMs show significant elevation in 13C labeled intermediates or end products of the hexosamine biosynthetic pathway (HBP), serine biosynthesis pathway (SBP), and pentose phosphate pathway (PPP). In line with these findings, our results also demonstrate that augmenting the carbon availability for these biosynthetic pathways by overexpressing phosphoenolpyruvate carboxykinase (PCK1 or PCK2) augments the ability of cardiomyocytes to proliferate. These data suggest that higher biosynthetic pathway flux may be required for cardiomyocyte proliferation. Informed by these results, we propose the general hypothesis that activation of ancillary biosynthetic pathways of glucose metabolism are required for cardiomyocyte proliferation. We suggest that higher biosynthetic pathway flux is required for building block synthesis and may be important for regulating pro-proliferative gene programs. During this project we will delineate the importance of each biosynthetic pathway in influencing cardiomyocyte proliferation. First, using pharmacological and virus-based approaches, we will determine the specific contribution of the HBP, SBP and PPP pathways to myocyte proliferation. In addition, we will investigate the influence of increasing the carbon flux in biosynthetic pathway through overexpression of PCK1, or PCK2 on cardiac function and repair in vivo. The aims of this project are: Specific Aim 1: Delineate the contribution of each biosynthetic pathway on cardiomyocyte proliferation. Specific Aim 2: Investigate the functional efficacy of increasing carbon flux in biosynthetic pathways on cardiac repair in vivo.