Transcriptomic analysis of myocardium-specific Creld1 knockout mice at E13.5 and P3

Purpose: The aim of the study was to decipher the function of Creld1 in the myocardium during embryonic and postnatal heart development. Methods: We generated conditional knockout (KO) mice lacking Creld1 in cells expressing the Myosine Heavy Chain (MyHC, myocardial cells). Embryonic (E13.5, n=4) and postnatal (P3, n=3) hearts from both wild-type (WT) and KO mice were isolated and postnatal hearts were further split into atria and ventricles. Total RNA was extracted, mRNA purified, converted into cDNA and sequenced using a NextSeq500 system (Illumina).The reads passing default quality filters were aligned to the mouse genome (mm10). Results: More than 5.1 million aligned reads were retrieved in each sample.The expression profiles of the postnatal KO samples underline drastic anormalies in the hearts and commencing heart failure particularly in the atria. In embryonic KO hearts the transciption of Notch1 signalling components and consequently extracellular matrix (ECM) homeostasis was altered, whereas transcription in Nfatc1 and Vegf signalling pathways was unchanged. Conclusion: This study shows that myocardial Creld1 is a key morphogenic factor in the developing heart and as it regulates Notch1 signalling and, thereby, the ECM during cardiac wall development. Transcriptomes of myocardium-specific Creld1 knockout mice were compared to wild-type controls at E13.5 and P3.研究目的：本研究旨在解析Creld1在胚胎期与出生后心脏发育过程中心肌组织中的功能。 研究方法：我们构建了在肌球蛋白重链（Myosine Heavy Chain, MyHC，即心肌细胞）阳性细胞中敲除Creld1的条件性基因敲除（conditional knockout, KO）小鼠。分别分离野生型（wild-type, WT）与基因敲除小鼠的胚胎期（E13.5，n=4）及出生后（P3，n=3）心脏组织，并将出生后心脏样本进一步分离为心房与心室。提取总RNA，纯化mRNA并反转录为cDNA，随后采用Illumina NextSeq500系统进行测序。将通过默认质量过滤的reads比对至小鼠基因组mm10版本。 研究结果：每个样本均获得超过510万条比对成功的reads。出生后基因敲除样本的表达谱显示心脏存在显著异常，尤其在心房中已出现早期心力衰竭表现。胚胎期基因敲除小鼠心脏中，Notch1信号通路组分的转录及随之而来的细胞外基质（extracellular matrix, ECM）稳态发生改变，而Nfatc1与Vegf信号通路的转录水平无明显变化。 研究结论：本研究证实，心肌组织中的Creld1是心脏发育过程中的关键形态发生因子，其通过调控Notch1信号通路进而影响心脏壁发育过程中的细胞外基质稳态。本研究将心肌特异性Creld1基因敲除小鼠的转录组与E13.5、P3阶段的野生型对照组进行了对比分析。