Aims Intracellular calcium (Ca2+) overload is known to play a critical role in the development of cardiac dysfunction. Despite the remarkable improvement in managing the progression of heart disease, developing effective therapies for heart failure (HF) remains a challenge. A better understanding of molecular mechanisms that maintain proper Ca2+ levels and contractility in the injured heart could be of therapeutic value. Methods and results Here, we report that transcription factor zinc finger E-box-binding homeobox 2 (ZEB2) is induced by hypoxia-inducible factor 1-alpha (HIF1α) in hypoxic cardiomyocytes and regulates a network of genes involved in Ca2+ handling and contractility during ischaemic heart disease. Gain- and loss-of-function studies in genetic mouse models revealed that ZEB2 expression in cardiomyocytes is necessary and sufficient to protect the heart against ischaemia-induced diastolic dysfunction and structural remodelling. Moreover, RNA sequencing of ZEB2-overexpressing (Zeb2 cTg) hearts post-injury implicated ZEB2 in regulating numerous Ca2+-handling and contractility-related genes. Mechanistically, ZEB2 overexpression increased the phosphorylation of phospholamban at both serine-16 and threonine-17, implying enhanced activity of sarcoplasmic reticulum Ca2+-ATPase (SERCA2a), thereby augmenting SR Ca2+ uptake and contractility. Furthermore, we observed a decrease in the activity of Ca2+-dependent calcineurin/NFAT signalling in Zeb2 cTg hearts, which is the main driver of pathological cardiac remodelling. On a post-transcriptional level, we showed that ZEB2 expression can be regulated by the cardiomyocyte-specific microRNA-208a (miR-208a). Blocking the function of miR-208a with anti-miR-208a increased ZEB2 expression in the heart and effectively protected from the development of pathological cardiac hypertrophy. Conclusion Together, we present ZEB2 as a central regulator of contractility and Ca2+-handling components in the mammalian heart. Further mechanistic understanding of the role of ZEB2 in regulating Ca2+ homeostasis in cardiomyocytes is an essential step towards the development of improved therapies for HF.

中文翻译：

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缺氧反应性锌指 E 盒结合同源盒 2 (ZEB2) 调节受损心脏中的钙处理基因网络


目的 众所周知，细胞内钙 (Ca2+) 超载在心功能障碍的发展中发挥着关键作用。尽管在控制心脏病进展方面取得了显着进步，但开发心力衰竭（HF）的有效疗法仍然是一个挑战。更好地了解在受伤的心脏中维持适当的 Ca2+ 水平和收缩力的分子机制可能具有治疗价值。方法和结果在这里，我们报告转录因子锌指E盒结合同源盒2（ZEB2）由缺氧心肌细胞中的缺氧诱导因子1-α（HIF1α）诱导，并调节参与Ca2+处理和收缩性的基因网络缺血性心脏病期间。遗传小鼠模型的功能获得和功能丧失研究表明，心肌细胞中的ZEB2表达对于保护心脏免受缺血引起的舒张功能障碍和结构重塑是必要且充分的。此外，对 ZEB2 过表达 (Zeb2 cTg) 心脏损伤后的 RNA 测序表明，ZEB2 调节许多 Ca2+ 处理和收缩性相关基因。从机制上讲，ZEB2 过表达增加了受磷蛋白丝氨酸 16 和苏氨酸 17 的磷酸化，这意味着肌浆网 Ca2+-ATP 酶 (SERCA2a) 的活性增强，从而增强 SR Ca2+ 摄取和收缩性。此外，我们观察到 Zeb2 cTg 心脏中 Ca2+ 依赖性钙调神经磷酸酶/NFAT 信号传导活性降低，这是病理性心脏重塑的主要驱动因素。在转录后水平上，我们发现ZEB2的表达可以通过心肌细胞特异性的microRNA-208a（miR-208a）来调节。 用抗miR-208a阻断miR-208a的功能可增加心脏中ZEB2的表达，并有效防止病理性心脏肥大的发展。结论 总之，我们将ZEB2 视为哺乳动物心脏收缩力和Ca2+ 处理成分的中心调节因子。进一步了解 ZEB2 在调节心肌细胞 Ca2+ 稳态中的作用是开发改进的心力衰竭疗法的重要一步。