Non-coding RNAs, particularly small Cajal-body associated RNAs (scaRNAs), play a significant role in spliceosomal RNA modifications. While their involvement in ischemic myocardium regeneration is known, their role in cardiac development is unexplored. We investigated scaRNA20's role in iPSC differentiation into cardiomyocytes (iCMCs) via overexpression and knockdown assays. We measured scaRNA20-OE-iCMCs and scaRNA20-KD-iCMCs contractility using Particle Image Velocimetry (PIV), comparing them to control iCMCs. We explored scaRNA20's impact on alternative splicing via pseudouridylation (Ψ) of snRNA U12, analyzing its functional consequences in cardiac differentiation. scaRNA20-OE-iPSC differentiation increased beating colonies, upregulated cardiac-specific genes, activated TP53 and STAT3, and preserved contractility under hypoxia. Conversely, scaRNA20-KD-iCMCs exhibited poor differentiation and contractility. STAT3 inhibition in scaRNA20-OE-iPSCs hindered cardiac differentiation. RNA immunoprecipitation revealed increased Ψ at the 28th uridine of U12 RNA in scaRNA20-OE iCMCs. U12-KD iCMCs had reduced cardiac differentiation, which improved upon U12 RNA introduction. In summary, scaRNA20-OE in iPSCs enhances cardiomyogenesis, preserves iCMC function under hypoxia, and may have implications for ischemic myocardium regeneration.

中文翻译：

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scaRNA20促进小核snRNA U12的假尿苷酸化修饰并改善心肌发生

非编码 RNA，特别是小卡哈尔体相关 RNA (scaRNA)，在剪接体 RNA 修饰中发挥重要作用。虽然它们参与缺血性心肌再生是已知的，但它们在心脏发育中的作用尚未被探索。我们通过过表达和敲低实验研究了 scaRNA20 在 iPSC 分化为心肌细胞 (iCMC) 中的作用。我们使用粒子图像测速 (PIV) 测量了 scaRNA20-OE-iCMC 和 scaRNA20-KD-iCMC 的收缩性，并将它们与对照 iCMC 进行比较。我们通过 snRNA U12 的假尿苷化 (Ψ) 探索了 scaRNA20 对选择性剪接的影响，分析了其在心脏分化中的功能后果。scaRNA20-OE-iPSC 分化增加了跳动集落，上调了心脏特异性基因，激活了 TP53 和 STAT3，并在缺氧条件下保留了收缩性。相反，scaRNA20-KD-iCMC 表现出较差的分化和收缩性。scaRNA20-OE-iPSC 中的 STAT3 抑制阻碍了心脏分化。RNA 免疫沉淀显示 scaRNA20-OE iCMC 中 U12 RNA 的第 28 个尿苷处 Ψ 增加。U12-KD iCMC 减少了心脏分化，这在引入 U12 RNA 后得到改善。总之，iPSC 中的 scaRNA20-OE 增强心肌生成，在缺氧条件下保留 iCMC 功能，并可能对缺血心肌再生具有影响。