Cardiomyocyte cell cycle activity in injured hearts

受伤心脏中心肌细胞的细胞周期活动

• 批准号: 9308377
• 负责人: LOREN J FIELD
• 金额: $ 39万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-06 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9308377
• 关键词: Address; Adult; Algorithms; Anatomy; Animals; Atlases; Back; Backcrossings; Biological Assay; Birth; Bromodeoxyuridine; Cardiac; Cardiac Myocytes; Cell Cycle; Cell Cycle Progression; Cell Nucleus; Clonal Expansion; Coronary artery; Cytokinesis; DNA biosynthesis; Data; Data Set; Development; Drops; Embryo; Gender; Genes; Genetic; Goals; Growth; Heart; Heart Diseases; Human; Inbred Mouse; Inbreeding; Individual; Infarction; Infusion procedures; Injury; Intervention; Ischemia; Label; Lead; Ligation; Modeling; Monitor; Morphologic artifacts; Mus; Myocardial; Myocardial Infarction; Myocardium; Nature; Perinatal; Physiologic pulse; Population; Rattus; Reperfusion Injury; Reperfusion Therapy; Reporter; S Phase; Sampling; Signal Transduction; Stem cells; System; Systems Analysis; Testing; Thymidine; Tissues; Transcriptional Activation; Transgenic Organisms; Variant; clinically relevant; digital imaging; experimental study; imaging system; injured; insight; mathematical model; migration; muscle form; novel; postnatal; progenitor; regenerative; response; restoration; therapy development

Cardiomyocyte cell cycle induction offers the potential for restoration of myocardial mass, and consequently contractile function, following cardiac injury. Considerable effort has thus been invested studying the degree to which cardiomyocytes can reenter the cell cycle and progress through cytokinesis in normal and injured adult mammalian hearts. Using a transgenic reporter system to identify cardiomyocyte nuclei in tissue sections in conjunction with continuous BrdU infusion, we have developed a digital imaging and analysis system which permits both quantitation and 3D anatomical mapping of cumulative cardiomyocyte S-phase activity across the entire heart. Using this system, we observed discrete clusters of cardiomyocyte S-phase activity in mice with permanent coronary artery ligation. We also observed very high rates of cardiomyocyte S-phase activity in the remote myocardium of mice with ischemia/reperfusion (I/R) injury. The studies proposed in this application will identify the underlying mechanistic basis for the differential cardiomyocyte cell cycle responses observed following myocardial injury. In Specific Aim 1, the variability in cardiomyocyte S-phase induction and cell cycle progression following permanent coronary artery ligation will be established and the resulting data sets will then be used for mathematical modeling with the goal of establish sampling criteria to quantitate total heart cardiomyocyte S-phase activity which takes into account these intrinsic anatomical variations. Other studies will determine if the observed clusters of S-phase activity arise from the clonal expansion of a subset of cardiomyocytes which retain the potential for cell cycle reentry. In Specific Aim 2, I/R injury will be performed in reporter mice maintained in an inbred genetic background to determine if the nature and/or degree of injury are responsible for high levels of cell cycle induction in the remote myocardium. Other studies will utilize informative backcrosses to determine the extent to which modifying genes can impact cardiomyocyte cell cycle reentry following I/R injury. In both Aims, the degree to which the S-phase positive cardiomyocytes progress through the cell cycle will also be quantitated. The proposed experiments will establish a 3D atlas of cardiomyocyte S-phase activity in response to commonly used and clinically relevant injury models, and will establish the degree to which increased levels of cardiomyocyte DNA synthesis contribute to polyploidization, multi-nucleation, and/or cardiomyocyte renewal. In addition, these experiments will characterize the impact of gender, genetic background and mode of injury on the magnitude of cardiomyocyte cell cycle reentry, as well as determine the consequences of natural variation in cardiomyocyte cell cycle activity on cardiac function post-injury. These data will provide useful insight for the development of interventional strategies with which to promote regenerative growth of the heart, as well as provide a comprehensive reference set for studies aimed at inducing cardiomyocyte renewal.

心肌细胞细胞周期诱导提供了恢复心肌质量的潜力，因此 心脏损伤后的收缩功能。因此，我们投入了大量的精力来研究学位 在正常和受伤的成人中，心肌细胞可以重新进入细胞周期并通过胞质分裂进行进展 哺乳动物的心脏。使用转基因报告系统识别组织切片中的心肌细胞核 结合连续 BrdU 输注，我们开发了一种数字成像和分析系统， 允许对整个心肌细胞 S 期活动的累积进行定量和 3D 解剖图绘制 整个心脏。使用该系统，我们观察到小鼠心肌细胞 S 期活性的离散簇 永久性冠状动脉结扎术。我们还观察到心肌细胞 S 期活性的比率非常高 缺血/再灌注（I/R）损伤小鼠的远端心肌。本申请中提出的研究将 确定观察到的差异心肌细胞细胞周期反应的潜在机制基础 心肌损伤后。在具体目标 1 中，心肌细胞 S 期诱导和细胞周期的变异性 将确定永久性冠状动脉结扎后的进展情况，并产生数据集 然后用于数学建模，目的是建立采样标准来定量总心脏 心肌细胞 S 期活动考虑了这些内在的解剖变化。其他研究 将确定观察到的 S 期活性簇是否源自某个子集的克隆扩展 心肌细胞保留细胞周期重入的潜力。在具体目标 2 中，将进行 I/R 损伤 在近交遗传背景下维持的报告小鼠中，以确定损伤的性质和/或程度 负责远端心肌中高水平的细胞周期诱导。其他研究将利用 信息回交以确定修饰基因影响心肌细胞周期的程度 I/R 损伤后重返大气层。在这两个目标中，S 期阳性心肌细胞进展的程度 整个细胞周期也将被定量。拟议的实验将建立一个 3D 图集 心肌细胞 S 期活动对常用和临床相关损伤模型的反应，并将 确定心肌细胞 DNA 合成水平的增加对多倍化的贡献程度， 多核和/或心肌细胞更新。此外，这些实验将表征 性别、遗传背景和损伤方式对心肌细胞细胞周期再进入程度的影响 确定心肌细胞细胞周期活动自然变化对心脏功能的影响 受伤后。这些数据将为干预策略的制定提供有用的见解，以便 促进心脏的再生生长，并为旨在研究的研究提供全面的参考集 诱导心肌细胞更新。