Maturation of hiPSC-derived cardiomyocytes in tri-cellular cardiac microtissues promotes adult alternative splicing of SCN5A revealing effects of mutations in cardiac disease   

ABSTRACT: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are used to examine in vitro the effect of mutations in the cardiac sodium channel gene SCN5A, associated with cardiac arrhythmias. Postnatally SCN5A undergoes a fetal-to-adult isoform switch, but hiPSC-CMs in conventional 2-dimensional cultures are fetal-like. This impedes evaluation of mutations in the adult isoform. Here, we derived hiPSC-CMs from a patient carrying compound mutations in the adult SCN5A exon 6B and in exon 4 and generated isogenic corrected lines. In hiPSC-CM 2-dimensional culture, exon 6B mutation did not affect single-cell electrophysiology because of its limited expression. CRISPR/Cas9-mediated excision of the fetal exon 6A with did not promote adult SCN5A expression, rather it impaired the splicing. By maturing hiPSC-CMs in three-dimensional tri-cell type cardiac microtissues, SCN5A underwent isoform switch and revealed the functional effect of exon 6B mutation. Upregulation of the splicing factor MBNL1 in hiPSC-CMs either by culture in microtissues or by overexpression was sufficient to promote exon 6B inclusion. Our results support the ability to study developmentally regulated cardiac genes and postnatal cardiac arrhythmias using hiPSC cardiac cells.

ORGANISM(S): Homo sapiens

PROVIDER: GSE180290 | GEO | 2023/05/03

REPOSITORIES: GEO