PDF(Pubmed)
Abstract：
Telomeres as the protective ends of linear chromosomes, are synthesized by the enzyme telomerase (TERT). Critically short telomeres essentially contribute to aging-related diseases and are associated with a broad spectrum of disorders known as telomeropathies. In cardiomyocytes, telomere length is strongly correlated with cardiomyopathies but it remains ambiguous whether short telomeres are the cause or the result of the disease. In this study, we employed an inducible CRISPRi human induced pluripotent stem cell (hiPSC) line to silence TERT expression enabling the generation of hiPSCs and hiPSC-derived cardiomyocytes with long and short telomeres. Reduced telomerase activity and shorter telomere lengths of hiPSCs induced global transcriptomic changes associated with cardiac developmental pathways. Consequently, the differentiation potential towards cardiomyocytes was strongly impaired and single cell RNA sequencing revealed a shift towards a more smooth muscle cell like identity in the cells with the shortest telomeres. Poor cardiomyocyte function and increased sensitivity to stress directly correlated with the extent of telomere shortening. Collectively our data demonstrates a TERT dependent cardiomyogenic differentiation defect, highlighting the CRISPRi TERT hiPSCs model as a powerful platform to study the mechanisms and consequences of short telomeres in the heart and also in the context of telomeropathies.
摘要：
端粒作为线性染色体的保护性末端，由端粒酶(TERT)合成。极短的端粒基本上有助于衰老相关疾病,并且与称为端粒病的广谱病症相关。在心肌细胞中，端粒长度与心肌病密切相关，但端粒短是该疾病的原因还是结果仍然不明确。在这项研究中,我们使用诱导型CRISPri人诱导多能干细胞(hiPSC)细胞系沉默TERT表达,从而能够产生具有长端粒和短端粒的hiPSC和hiPSC衍生的心肌细胞.hiPSC的端粒酶活性降低和端粒长度缩短诱导与心脏发育途径相关的整体转录组变化。因此,向心肌细胞的分化潜能严重受损,单细胞RNA测序显示端粒最短的细胞向更平滑肌细胞样的身份转变.心肌细胞功能不良和对压力敏感性增加与端粒缩短的程度直接相关。我们的数据共同证明了TERT依赖性心肌分化缺陷，强调CRISPRiTERThiPSCs模型是一个强大的平台，可以研究心脏和端粒病变中短端粒的机制和后果。
