An Ultrasensitive Calcium Reporter System via CRISPR-Cas9-Mediated Genome Editing in Human Pluripotent Stem Cells

• Published in: iScience 2018-11, Vol.9, p.27-35
• Main Authors: Jiang, Yuqian, Zhou, Yuxiao, Bao, Xiaoping, Chen, Chuanxin, Randolph, Lauren N, Du, Jing, Lian, Xiaojun Lance
• Format: Article
• Language: English
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2018.10.007

Genetically encoded calcium indicator (GCaMP) proteins have been reported for imaging cardiac cell activity based on intracellular calcium transients. To bring human pluripotent stem cell (hPSC)-derived cardiomyocytes (CMs) to the clinic, it is critical to evaluate the functionality of CMs. Here, we show that GCaMP6s-expressing hPSCs can be generated and used for CM characterization. By leveraging CRISPR-Cas9 genome editing tools, we generated a knockin cell line that constitutively expresses GCaMP6s, an ultrasensitive calcium sensor protein. We further showed that this clone maintained pluripotency and cardiac differentiation potential. These knockin hPSC-derived CMs exhibited sensitive fluorescence fluctuation with spontaneous contraction. We then compared the fluorescence signal with mechanical contraction signal. The knockin hPSC-derived CMs also showed sensitive response to isoprenaline treatment in a concentration-dependent manner. Therefore, the GCaMP6s knockin hPSC line provides a non-invasive, sensitive, and economic approach to characterize the functionality of hPSC-derived CMs.