LncRNA expression profiling of the early mesoderm reveals LncCPR as a novel regulator of cardiogenesis in mice

Whole mount in situ hybridization analysis of the 17 lncRNAs revealed that lncRNAs 2410006H16Rik and 4930500J02Rik were expressed in mouse hearts at E9.5. 4930500J02Rik, renamed Long Noncoding Cardiac-promoting RNA (LncCPR), was also enriched in postnatal and adult heart tissue. We hypothesized that the loss of LncCPR expression would directly affect cardiogenesis. To test this hypothesis, we performed functional studies of ESC differentiation after knocking out the LncCPR gene with the CRISPR/Cas9 system. We profiled the transcriptome of mouse ES cells after the loss of LncCPR expression. We found the downregulation of Mesp1 and cardiac transcription factors, as well as a significant reduction in contractility and levels of cardiac structural protein TNNT2. Our findings indicate that LncCPR is a novel, specific regulator of Mesp1, and therefore, of early cardiogenesis.

对17种长链非编码RNA（long noncoding RNA, lncRNA）开展全胚胎原位杂交分析后发现，lncRNA 2410006H16Rik与4930500J02Rik在小鼠胚胎发育第9.5天（E9.5）的心脏组织中存在表达。其中4930500J02Rik被重新命名为长链非编码心脏促进RNA（Long Noncoding Cardiac-promoting RNA, LncCPR），该分子在出生后及成年小鼠的心脏组织中同样呈现富集表达。研究团队据此提出假设：LncCPR的表达缺失将直接影响心脏发生过程。为验证该假设，研究团队利用CRISPR/Cas9系统敲除LncCPR基因后，对胚胎干细胞（embryonic stem cell, ESC）的分化过程开展功能实验。随后，研究人员对LncCPR表达缺失的小鼠胚胎干细胞进行了转录组分析，结果显示，Mesp1及心脏转录因子的表达出现下调，同时细胞收缩能力与心脏结构蛋白TNNT2的表达水平均显著降低。本研究结果表明，LncCPR是调控Mesp1的新型特异性调控因子，进而参与早期心脏发生过程。