RNA-seq analysis of diploid and tetraploid neonatal rat cardiomyocytes. RNA-seq analysis of diploid and tetraploid neonatal rat cardiomyocytes

In response to pathological stress such as congenital heart disease and heart valvular disease, cardiomyocytes (CMs) generally increased the content of DNA and the number of nuclear. This process named CM polyploidization and multi-nucleation, result in the presence of multi-nucleated polyploid CM. However, the significance of multi-nucleated polyploid CM (M*Pc CM) for heart disease remains enigmatic. We speculated that the process of CM polyploidization and multinucleation may be an adaptative response, which may help CM function recovery and survive the stress condition. We sought to determine the mechanism of enhanced mitophagy in M*Pc CMs during hypoxia adaptation. Overall design: After hypoxia (1% oxygen) for 48h, neonatal rat cardiomyocytes (NRCMs) were stained with Hoechst 33342 and sorted into two subpopulation including diploid (2n) and tetraploid (4n). Four biological replicates of each condition (hypoxia) and flow cytometry sorting were used from independent experiments.

当受到先天性心脏病、心脏瓣膜病等病理应激刺激时，心肌细胞（cardiomyocytes, CMs）通常会增加DNA含量并提升细胞核数目。这一过程被称为心肌细胞多倍体化与多核化，最终形成多核多倍体心肌细胞（M*Pc CM）。然而，多核多倍体心肌细胞（M*Pc CM）在心脏疾病中的生物学意义仍尚不明确。我们推测，心肌细胞多倍体化与多核化过程或许是一种适应性应答，可帮助心肌细胞维持功能并在应激条件下存活。本研究旨在明确低氧适应过程中，多核多倍体心肌细胞内线粒体自噬增强的分子机制。总体实验设计：将新生大鼠心肌细胞（neonatal rat cardiomyocytes, NRCMs）置于1%氧浓度的低氧环境中培养48小时后，使用赫斯特33342（Hoechst 33342）进行染色，并通过流式细胞术分选得到二倍体（2n）与四倍体（4n）两个亚群。每个低氧处理及流式分选条件均设置4次生物学重复，所有重复均来自独立实验。