Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain.
Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece.
Metabolism. 2023 Jan;138:155344. doi: 10.1016/j.metabol.2022.155344. Epub 2022 Nov 12.
Arrhythmogenic cardiomyopathy (ACM) is characterized by life-threatening ventricular arrhythmias and sudden cardiac death and affects hundreds of thousands of patients worldwide. The deletion of Arginine 14 (p.R14del) in the phospholamban (PLN) gene has been implicated in the pathogenesis of ACM. PLN is a key regulator of sarcoplasmic reticulum (SR) Ca cycling and cardiac contractility. Despite global gene and protein expression studies, the molecular mechanisms of PLN-R14del ACM pathogenesis remain unclear. Using a humanized PLN-R14del mouse model and human induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs), we investigated the transcriptome-wide mRNA splicing changes associated with the R14del mutation. We identified >200 significant alternative splicing (AS) events and distinct AS profiles were observed in the right (RV) and left (LV) ventricles in PLN-R14del compared to WT mouse hearts. Enrichment analysis of the AS events showed that the most affected biological process was associated with "cardiac cell action potential", specifically in the RV. We found that splicing of 2 key genes, Trpm4 and Camk2d, which encode proteins regulating calcium homeostasis in the heart, were altered in PLN-R14del mouse hearts and human iPSC-CMs. Bioinformatical analysis pointed to the tissue-specific splicing factors Srrm4 and Nova1 as likely upstream regulators of the observed splicing changes in the PLN-R14del cardiomyocytes. Our findings suggest that aberrant splicing may affect Ca-homeostasis in the heart, contributing to the increased risk of arrythmogenesis in PLN-R14del ACM.
致心律失常性心肌病（ACM）的特征是危及生命的室性心律失常和心源性猝死，影响着全球数以十万计的患者。磷酸化兰尼碱（PLN）基因中精氨酸 14 缺失（p.R14del）与 ACM 的发病机制有关。PLN 是肌浆网（SR）Ca 循环和心脏收缩力的关键调节因子。尽管进行了全球基因和蛋白质表达研究，但 PLN-R14del ACM 发病机制的分子机制仍不清楚。使用人类 PLN-R14del 小鼠模型和人诱导多能干细胞衍生的心肌细胞（iPSC-CMs），我们研究了与 R14del 突变相关的转录组范围的 mRNA 剪接变化。我们鉴定了 >200 个显著的可变剪接（AS）事件，并且在 PLN-R14del 与 WT 小鼠心脏相比，在右心室（RV）和左心室（LV）中观察到不同的 AS 谱。AS 事件的富集分析表明，受影响最大的生物学过程与“心肌细胞动作电位”有关，特别是在 RV 中。我们发现，编码调节心脏钙稳态的蛋白质的 2 个关键基因 Trpm4 和 Camk2d 的剪接在 PLN-R14del 小鼠心脏和人 iPSC-CMs 中发生改变。生物信息学分析指出，组织特异性剪接因子 Srrm4 和 Nova1 可能是 PLN-R14del 心肌细胞中观察到的剪接变化的上游调节因子。我们的研究结果表明，异常剪接可能影响心脏中的钙稳态，导致 PLN-R14del ACM 心律失常发生风险增加。
