Sequence Variants Impacting Cardiomyocyte S-phase Activity in Inbred Mice Following Injury

序列变异影响近交小鼠损伤后心肌细胞 S 期活性

• 批准号: 10550204
• 负责人: LOREN J FIELD
• 金额: $ 50.44万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-15 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10550204
• 关键词: Abbreviations; Adult; Alleles; Anatomy; Animals; Apoptosis; Backcrossings; Bromodeoxyuridine; Candidate Disease Gene; Cardiac; Cardiac Myocytes; Cell Cycle; Cell Cycle Progression; Chromosome 3; Congenic Mice; Distal; Echocardiography; Exhibits; Genes; Genetic; Genetically Modified Animals; Heart; Heart Injuries; Heterozygote; Hypertrophy; Image Analysis; Inbred DBA Mice; Inbred Mouse; Inbred Strains Mice; Infarction; Infusion procedures; Injury; Location; Measurement; Molecular Analysis; Monitor; Mouse Strains; Mus; Myocardial; Myocardial Infarction; Natural regeneration; Nucleotides; Pattern; Phenotype; Reporter; S phase; Structure; System; Systems Analysis; Testing; Time; Transgenes; Transgenic Organisms; Validation; Variant; Ventricular Remodeling; autosome; chromosomal location; coronary fibrosis; exome sequencing; experimental study; genetic testing; genetic variant; genome editing; heart function; hemodynamics; improved; insight; interest; myocardial injury; offspring; protein structure; regenerative growth; therapeutic development; therapeutic target; trait; transcriptome sequencing

Numerous studies have shown that induction of cardiomyocyte cell cycle activity can have a profound beneficial impact on cardiac structure and function following myocardial infarction. It has also been shown that genetic background can impact the intrinsic rate of cardiomyocyte cell cycle activity in mice. We have observed that mice in a DBA/2J genetic background (abbreviated DBA) have very low levels of cardiomyocyte cell cycle activity following myocardial infarction. However, when crossed with C57Bl6/NCR mice (abbreviated NCR), the resulting (DBA x NCR)-F1 animals mice exhibit a marked increase in cardiomyocyte S-phase activity following infarction, indicating the presence of an autosomal gene (or genes) in the NCR background which acts in a dominant manner to facilitate cell cycle re-entry. Analysis of backcross mice established that this gene (or genes) resides in a region of interest (ROI) located on the distal end of chromosome 3. The experiments proposed in Aim 1 will test hypothesis that a single gene within the ROI is responsible for elevated cardiomyocyte S-phase activity post-infarction. Candidate genes within this region will be identified based on expression patterns observed in infarcted DBA vs. NCR hearts as well as by the presence of sequence variants predicted to impact protein structure and/or activity. The candidates will be systematically tested by generating genetically modified animals, subjecting them to myocardial infarction, and then monitoring the level of cardiomyocyte S-phase activity; an induction of cardiomyocyte cell cycle activity would confirm that the candidate gene being tested is responsible for the trait. The experiments proposed in Aim 2 will test the hypothesis that the elevated cell cycle activity encoded by the NCR ROI alleles has a positive impact on the diminished cardiac function and adverse myocardial remodeling which is encountered post-infarction. Congenic mice in a DBA genetic background which retain heterozygosity on the distal end of chromosome 3 and thus carry the NCR allele (or alleles) which is a major contributor to cardiomyocyte S-phase induction will be generated. The mice will then be subjected to myocardial infarction and longitudinal functional analysis. Terminal analyses will include comprehensive hemodynamic measurements as well as assessment of adverse remodeling (cardiomyocyte apoptosis, hypertrophy and myocardial fibrosis); relative improvements in cardiac function and structure would indicate a beneficial effect from the NCR-encoded cell cycle activity following myocardial injury. Ultimately, the identification and validation of genes underlying intrinsic differences in cardiomyocyte cell cycle rates observed in different strains of mice could suggest potential therapeutic targets with which to enhance regenerative growth in injured hearts.

大量研究表明，诱导心肌细胞细胞周期活性可以具有深刻的 对心肌梗塞后心脏结构和功能的有益影响。也已经表明 遗传背景会影响小鼠心肌细胞周期活性的内在速率。我们已经观察到 DBA/2J遗传背景（缩写DBA）中的小鼠的心肌细胞周期水平非常低 心肌梗塞后的活动。但是，当与C57BL6/NCR小鼠（缩写NCR）交叉时， 产生的（DBA X NCR）-F1动物小鼠在心肌细胞S相活动中表现出明显增加 梗塞，表明在NCR背景中存在常染色体基因（或基因），该基因作用于A 促进细胞周期重新进入的主要方式。反杂交小鼠的分析确定该基因（或基因） 位于位于染色体3的远端的感兴趣区域（ROI）。 AIM 1将检验ROI中的单个基因负责升高心肌细胞S期的假设 界面后的活动。该区域内的候选基因将根据表达模式识别 在梗塞的DBA与NCR心脏中观察到，以及通过预测的序列变体的存在 蛋白质结构和/或活性。候选人将通过生成基因修饰来系统地测试 动物，使它们遭受心肌梗塞，然后监测心肌细胞的水平 活动;心肌细胞细胞周期活性的诱导将确认正在测试的候选基因为 负责特征。 AIM 2中提出的实验将测试升高细胞周期的假设 NCR ROI等位基因编码的活动对降低的心脏功能有积极影响 心肌重塑后施加后遇到的心肌重塑。 DBA遗传背景中的先天小鼠 在3染色体的远端保持杂合性，从而携带NCR等位基因（或等位基因） 将产生导致心肌细胞S期诱导的主要贡献者。然后，老鼠将受到 心肌梗塞和纵向功能分析。终端分析将包括全面 血液动力学测量以及不良重塑的评估（心肌细胞凋亡， 肥大和心肌纤维化）；心脏功能和结构的相对改善将表明 心肌损伤后NCR编码的细胞周期活性产生的有益作用。最终，标识 并验证在不同 小鼠的菌株可能表明潜在的治疗靶标，以增强受伤的再生生长 心。