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.

心肌梗塞（MI）是德国死亡的主要原因之一。由于急性事件中的结果提高，心力衰竭作为MI的长期续集的流行率目前正在上升。这主要是由于成年哺乳动物心肌的再生能力有缺陷，这导致心肌细胞衰减后的疤痕形成，而不是恢复功能性肌肉组织。最近证明，与成年小鼠相比，新生小鼠可以在心肌顶点切除或（冷冻）肌电疗法后完全再生心肌。这种能够检查出生后哺乳动物心肌的再生机制，以及确定成人心脏中再生缺陷的原因。鉴定出可促进新生儿心脏再生的基因或调节性RNA可能被用作改善MI后心脏再生的疗法，以改善MI后的患者的心脏再生。 在该提案的初步工作中，我们发现心肌细胞转录因子GATA4的心脏表达在出生时很高，但从产后第7天开始急剧下降，当时心肌的再生能力也大大降低。由于GATA4在胚胎发育过程中促进了心肌细胞的增殖，因此我们假设它可能支持损伤后的心肌再生。因此，我们将在新生儿心肌细胞特异性GATA4敲除（GATA4-CKO）和对照小鼠中分析心脏冷冻术后心脏再生。我们将在两组小鼠诱导后在多个时间点上探测心肌疤痕，心肌细胞增殖和肥大，血管生成，心脏炎症以及心脏转录组（通过深层测试）的大小。首先结果表明，在心肌冷冻术后7天，在GATA4-CKO小鼠的GATA4-CKO小鼠中，疤痕明显更大，心肌细胞增殖减少。在深入的分析中，我们旨在确定促进心肌再生的先前未知的GATA4依赖性因素。将在心脏外植体培养物以及孤立的胎儿和新生儿心肌细胞中检查确定的候选基因的再生效力。 此外，我们将使用腺病毒和AAV9载体在7天大的心脏以及成年野生型小鼠的心脏中过表达GATA4，其中内源性GATA4表达大大下调，并将分析这种治疗方法是否可以改善心肌再生。以类似的方式，我们旨在过表达选择候选基因，并确定其在心脏冷冻夹后的再生潜力。