CRISPR/Cas9 Gene Editing of RYR2 in Human iPSC-Derived Cardiomyocytes to Probe Ca2+ Signaling Aberrancies of CPVT Arrhythmogenesis

Human-induced pluripotent stem cells (hiPSCs) provide a powerful platform to study biophysical and molecular mechanisms underlying the pathophysiology of genetic mutations associated with cardiac arrhythmia. Human iPSCs can be generated by reprograming of dermal fibroblasts of normal or diseased individuals and be differentiated into cardiac myocytes. Obtaining biopsies from patients afflicted with point mutations causing arrhythmia is often a cumbersome process even when patients are available. Recent development of CRISPR/Cas9 gene editing system makes it, however, possible to introduce arrhythmia-associated point mutations at the desired loci of the wild-type hiPSCs in relatively short times. This platform was used by us to compare the Ca2+ signaling phenotypes of cardiomyocytes harboring point mutations in cardiac Ca2+ release channel, type-2 ryanodine receptor (RyR2), since over 200 missense mutations in RYR2 gene appear to be associated with catecholaminergic polymorphic ventricular tachycardia (CPVT1). We have created cardiac myocytes harboring mutations in different domains of RyR2, to study not only their Ca2+ signaling consequences but also their drug and domain specificity as related to CPVT1 pathology. In this chapter, we describe our procedures to establish CRISPR/Cas9 gene-edited hiPSC-derived cardiomyocytes.