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心肌梗死会导致心肌细胞(CM)不可逆转的丧失，并经常导致心力衰竭。至 替换丢失的细胞，我们确定了一种细胞周期调节因子的组合，可以诱导成人稳定的胞质分裂 有丝分裂后细胞。细胞周期蛋白依赖性激酶1(CDK1)、细胞周期蛋白4(CDK4)、细胞周期蛋白B1(Cyclin B1)和细胞周期蛋白D1(Cyclin D1)的过度表达 As4F)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 这一诱导心肌细胞更新的方案为理解相关机制提供了新的机会。 在心肌细胞的增殖中。与这一发现相关的最有趣的发现之一是证实了 代谢重新编程和心肌细胞增殖之间的联系。尽管在那里的增殖细胞中 代谢变化和细胞增殖之间有很强的相关性，目前尚不清楚新陈代谢如何 影响心肌细胞的增殖能力。在过去的两年里，与希尔博士合作 小组，我已经产生了初步数据，表明心肌细胞增殖与 能量新陈代谢方面的显著重新编程。从谱系追踪中分离的增殖心肌细胞 (MADM)小鼠，RNA-seq数据表明脂肪酸氧化基因显著下调，而 生物合成途径酶在人IPSC来源心肌细胞中的表达，4F的表达 降低线粒体呼吸和分解代谢活性。利用稳定同位素分解的代谢组学 (SIRM)，我们证明4F感染的HIPS-CMS显示13C标记的中间体或 己糖胺生物合成途径(HBP)、丝氨酸生物合成途径(SBP)和戊糖的最终产物 磷酸途径(PPP)。与这些发现一致，我们的结果还表明，增加碳 过表达PCK1或PCK1对这些生物合成途径的有效性 PCK2)增强心肌细胞的增殖能力。这些数据表明，更高的生物合成 心肌细胞的增殖可能需要途径流。在这些结果的启发下，我们建议一般 假设需要激活葡萄糖代谢的辅助生物合成途径 心肌细胞增殖。我们认为积木需要较高的生物合成途径通量。 合成，并可能是重要的调节促增殖的基因程序。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，使用 药理学和基于病毒的方法，我们将确定HBP，SBP和 PPP途径促进心肌细胞增殖。此外，我们还将研究增加碳通量的影响。 在生物合成途径中，PCK1或PCK2过表达对心脏功能和体内修复的影响。这个 本项目的目标是：具体目标1：描述每条生物合成途径对心肌细胞的贡献 扩散。特定目标2：研究增加生物合成途径中碳通量的功能效果 关于体内心脏修复的研究。

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.