Maturation of hiPSC-derived cardiomyocytes promotes adult alternative splicing of SCN5A and reveals changes in sodium current associated with cardiac arrhythmia.

Aims: Human-induced pluripotent stem cell-cardiomyocytes (hiPSC-CMs) are widely used to study arrhythmia-associated mutations in ion channels. Among these, the cardiac sodium channel SCN5A undergoes foetal-to-adult isoform switching around birth. Conventional hiPSC-CM cultures, which are phenotypically foetal, have thus far been unable to capture mutations in adult gene isoforms.