Impact of cardiomyocyte cell cycle activity on atrial structural and functional remodeling following myocardial infarction

心肌细胞细胞周期活性对心肌梗死后心房结构和功能重塑的影响

• 批准号: 10612944
• 负责人: LOREN J FIELD
• 金额: $ 64.12万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-22 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10612944
• 关键词: Acute myocardial infarction; Address; Adult; Anatomy; Apoptosis; Atrial Fibrillation; Atrial Function; Bacterial Artificial Chromosomes; Blood capillaries; CDK4 gene; CDKN2A gene; Calcium; Cardiac Myocytes; Cell Cycle; Cell Cycle Progression; Cell Nucleus; Cell Separation; Cells; Chronic; Clinical Research; Complex; Coronary; Coronary artery; Cytokinesis; Data; Development; Dilatation - action; Echocardiography; Electrophysiology (science); Exhibits; Fibrosis; Frequencies; Functional disorder; Genetic Models; Harvest; Heart; Heart Atrium; Human; Hypertrophy; Image; Individual; Infarction; Infiltration; Injury; Intervention; Kinetics; Laboratories; Laser Scanning Microscopy; Left; Left Atrial Function; Left atrial structure; Ligation; Location; Maps; Mechanics; Mediating; Mitosis; Modeling; Molecular; Mus; Myocardial; Myocardial Infarction; Myocardium; Optics; Organ; Pathologic; Patients; Phosphotransferases; Play; Predisposition; Process; Rattus; Reporter; Reporting; Rodent; Role; S phase; Secondary to; Shortening Fraction; Surface; System; Testing; Therapeutic Intervention; Tissues; Transgenes; Transgenic Mice; Vascularization; Ventricular; Whole Organism; Wild Type Mouse; anillin; density; event cycle; experimental study; heart function; hemodynamics; imaging system; immune cell infiltrate; inhibitor; insight; interstitial cell; mature animal; mortality; mouse model; nerve supply; new therapeutic target; novel; postnatal; prevent; response; sham surgery; transcriptome; transgene expression; two-photon; voltage

Both experimental and clinical studies have demonstrated that chronic myocardial infarction is associated with adverse remodeling of the left atrium, which in turn has an adverse impact on left atrial function. Left atrial dilatation is a powerful and independent predictor of mortality after myocardial infarction, but the mechanisms underlying the remodeling process are only poorly understood. Surprisingly, we have observed very high rates of cardiomyocyte cell cycle activity in the left atrium of infarcted mice. However, the role that cardiomyocyte cell cycle activity plays in mitigating or exacerbating structural and/or functional remodeling following myocardial infarction is not known. To directly address this question, we have generated a transgenic mouse model wherein infarct-induced left atrial cell cycle activity is silenced secondary to p16-Ink4a (p16) expression (p16 is a potent inhibitor of the proliferative kinase Cdk4 and transgenic expression in adult animals has previously been shown to be a potent cell cycle inhibitor). Here we propose to compare wild-type and p16 transgenic mice to determine the impact of atrial cardiomyocyte cell cycle activation on left atrial structural and functional remodeling following infarction. The experiments proposed in Aim 1 will determine the degree to which cardiomyocyte cell cycle activity impacts structural atrial remodeling following myocardial infarction. Left atrial structural analyses will be performed (a) at the tissue level to quantitate myocardial mass, cardiomyocyte number, fibrosis, immune cell infiltration, autonomic innervation and capillary density, (b) at the cardiomyocyte level to quantitate the extent of cell cycle progression and cellular hypertrophy as well as frequency of cardiomyocyte apoptosis, and (c) at the molecular level to quantitate transcriptome changes. The experiments proposed in Aim 2 will determine the degree to which cardiomyocyte cell cycle activity impacts atrial function following myocardial infarction. Atrial functional analyses will be performed (a) at whole organism level to quantitate echocardiographic and hemodynamic parameters, (b) at the intact heart level to quantitate calcium and voltage transient parameters in the left atrium (via optical mapping) and of cell clusters within the intact heart (via two-photon laser scanning microscopy), and (c) at the isolated cell level to quantitate fractional shortening and calcium handling kinetics. Importantly, cross-referencing the cell and molecular data from Aim 1 with the imaging and functional data from Aim 2 should enable us to better determine which cell cycle-mediated changes have a relevant impact on cardiac function. Such information may suggest interventions aimed at reversing compromised left atrial function in infarcted hearts.

实验和临床研究均表明慢性心肌梗塞与 左心房的不良重塑，进而对左心房功能产生不利影响。左心房 扩张是心肌梗死后死亡率的有力且独立的预测因素，但其机制 人们对改造过程的背后了解甚少。令人惊讶的是，我们观察到非常高的比率 梗死小鼠左心房心肌细胞周期活动的影响。然而，心肌细胞的作用 循环活动可减轻或加剧心肌梗死后的结构和/或功能重塑 梗塞尚不清楚。为了直接解决这个问题，我们生成了一个转基因小鼠模型，其中 梗死诱导的左心房细胞周期活动继发于 p16-Ink4a (p16) 表达而沉默（p16 是一种有效的 增殖激酶 Cdk4 抑制剂和成年动物中的转基因表达先前已被证实 是一种有效的细胞周期抑制剂）。在这里，我们建议比较野生型和 p16 转基因小鼠以确定 心房心肌细胞细胞周期激活对左心房结构和功能重塑的影响 梗塞。目标 1 中提出的实验将确定心肌细胞细胞周期活动的程度 影响心肌梗死后的结构性心房重塑。左心房结构分析将 (a) 在组织水平上定量心肌质量、心肌细胞数量、纤维化、免疫细胞 浸润、自主神经支配和毛细血管密度，(b) 在心肌细胞水平上定量 细胞周期进展和细胞肥大以及心肌细胞凋亡的频率，以及（c） 分子水平来定量转录组变化。目标 2 中提出的实验将确定 心肌梗塞后心肌细胞周期活动对心房功能的影响程度。心房 将在整个有机体水平上进行功能分析，以定量超声心动图和 血流动力学参数，(b) 在完整的心脏水平上定量钙和电压瞬态参数 左心房（通过光学测绘）和完整心脏内的细胞簇（通过双光子激光扫描） 显微镜），和（c）在分离的细胞水平上定量缩短分数和钙处理动力学。 重要的是，将目标 1 中的细胞和分子数据与来自 目标 2 应该使我们能够更好地确定哪些细胞周期介导的变化对心脏有相关影响 功能。这些信息可能表明旨在逆转受损左心房功能的干预措施 梗塞的心脏。