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，慢性心肌梗死与 左心房的不利重构，这反过来又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一个强有力的独立预测因子，但其机制 对重塑过程的基本原理知之甚少令人惊讶的是，我们发现 心肌细胞的细胞周期活动在梗死小鼠的左心房。然而，心肌细胞 周期活动在减轻或加重心肌梗死后的结构和/或功能重塑中起作用 梗塞是未知的。为了直接解决这个问题，我们已经产生了转基因小鼠模型，其中 梗死诱导的左心房细胞周期活动沉默继发于p16-Ink 4a（p16）表达（p16是一种有效的抑制心肌梗死的细胞周期的机制）。 增殖激酶Cdk 4的抑制剂和成年动物中的转基因表达 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 心房肌细胞周期激活对高血压大鼠左房结构和功能重构的影响 梗塞目标1中提出的实验将确定心肌细胞细胞周期活性 影响心肌梗死后的结构性心房重塑。左心房结构分析将 （a）在组织水平上进行，以定量心肌质量、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）在心肌细胞水平定量 细胞周期进程和细胞肥大以及心肌细胞凋亡的频率，和（c）在 分子水平来定量转录组变化。目标2中提出的实验将确定 心肌细胞周期活动影响心肌梗死后心房功能的程度。心房 将进行功能分析（a）在整个生物体水平上定量超声心动图， 血流动力学参数，（B）在完整心脏水平定量钙和电压瞬态参数， 左心房（通过光学映射）和完整心脏内的细胞簇（通过双光子激光扫描 显微镜），和（c）在分离的细胞水平定量缩短分数和钙处理动力学。 重要的是，将来自Aim 1的细胞和分子数据与来自Aim 1的成像和功能数据进行交叉引用。 目的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功能有相关的影响。 功能这些信息可能表明，干预措施旨在逆转受损的左心房功能， 梗塞的心脏