Impact of the cardiomyocyte transcription factor GATA4 for cardiac regeneration

心肌细胞转录因子 GATA4 对心脏再生的影响

• 批准号: 288451429
• 负责人: Professor Dr. Jörg Heineke
• 金额: --
• 依托单位: European Center for Angioscience (ECAS)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/288451429?language=en
• 关键词: Impact; cardiomyocyte; transcription; factor; GATA4

Myocardial infarction (MI) is one of the main reasons for mortality in Germany. Because of improved outcome in the acute event, the prevalence of heart failure as long-term sequel of MI is currently rising. This is mainly due to the defective regeneration capacity of the adult mammalian myocardium, which leads to scar formation after cardiomyocyte demise rather than the restitution of functional muscle tissue. It was recently demonstrated that newborn mice, in contrast to adult mice, can completely regenerate the myocardium after myocardial apex resection or (cryo)-infarction. This enables examination of regenerative mechanisms in the mammalian myocardium right after birth as well as the identification of reasons for defective regeneration in the adult heart. Genes or regulatory RNAs identified to promote regeneration in the neonatal heart could potentially be used as therapy to improve cardiac regeneration after MI in patients in the future. In preliminary work for this proposal we found that cardiac expression of the cardiomyocyte transcription factor GATA4 is very high at birth, but sharply declines starting at postnatal day 7, when also the regenerative capacity of the myocardium becomes strongly diminished. Because GATA4 promotes cardiomyocyte proliferation during embryonic development, we hypothesize that it might support myocardial regeneration after injury. Therefore, we will analyze heart regeneration after cardiac cryoinjury in neonatal cardiomyocyte specific GATA4 knock-out (GATA4-CKO) and control mice. We will probe the size of the myocardial scar, cardiomyocyte proliferation and hypertrophy, angiogenesis, cardiac inflammation as well as the cardiac transcriptome (by deep-sequencing) at multiple time-points after the induction of injury in both groups of mice. First results revealed a significantly larger scar and reduced cardiomyocyte proliferation in GATA4-CKO mice 7 days after myocardial cryoinjury. In the deep-sequencing analysis, we aim to identify previously unknown GATA4 dependent factors that promote myocardial regeneration. The regenerative potency of identified candidate genes will be examined in cardiac explant culture as well as in isolated fetal and neonatal cardiomyocytes. In addition, we will use adenoviral and AAV9 vectors to overexpress GATA4 in the heart of 7 day old as well as adult wild-type mice, in which endogenous GATA4 expression is dramatically downregulated and will analyze whether this treatment can improve myocardial regeneration. In a similar manner, we aim to overexpress select candidate genes and determine their regenerative potential after cardiac cryoinjury.

在德国，心肌梗死(MI)是死亡的主要原因之一。由于急性事件预后的改善，心力衰竭作为心肌梗死的长期后遗症的患病率目前正在上升。这主要是由于成年哺乳动物心肌再生能力的缺陷，导致心肌细胞死亡后形成疤痕，而不是功能肌肉组织的恢复。最近的研究表明，与成年小鼠相比，新生小鼠在心肌尖部切除或(冷冻)梗死后可以完全再生心肌。这使得能够在出生后立即检查哺乳动物心肌的再生机制，以及识别成人心脏再生缺陷的原因。被确定为促进新生儿心脏再生的基因或调控RNA可能在未来用于改善患者心肌梗死后的心脏再生。在这项提议的前期工作中，我们发现心肌细胞转录因子GATA4在出生时心脏表达非常高，但从出生后第7天开始急剧下降，同时心肌的再生能力也变得强烈减弱。由于GATA4促进胚胎发育期间的心肌细胞增殖，我们推测它可能支持损伤后的心肌再生。因此，我们将分析新生心肌细胞特异性GATA4基因敲除(GATA4-CKO)小鼠和对照小鼠的心脏冷冻损伤后的心脏再生。我们将在两组小鼠诱导损伤后的多个时间点检测心肌瘢痕的大小、心肌细胞的增殖和肥大、血管生成、心脏炎症以及心脏转录组(通过深度测序)。首先，结果显示，GATA4-CKO小鼠在心肌冷冻损伤7天后，明显增加了疤痕，减少了心肌细胞的增殖。在深度测序分析中，我们的目标是确定以前未知的促进心肌再生的GATA4依赖因子。已确定的候选基因的再生能力将在心脏外植体培养以及分离的胎儿和新生儿心肌细胞中进行检测。此外，我们将使用腺病毒和AAV9载体在7日龄小鼠和成年野生型小鼠的心脏中过表达GATA4，其中内源性GATA4的表达显著下调，并将分析这种治疗是否可以促进心肌再生。以类似的方式，我们的目标是过表达选定的候选基因，并确定它们在心脏冷冻损伤后的再生潜力。