Key result
CRISPR-Cas9 corrects KCNQ1 mutation and reverses arrhythmogenic phenotypes in patient-derived cardiomyocytes.
Why the study?
The pathogenesis of KCNQ1 mutations causing inherited long QT syndrome and the potential for gene correction using patient-specific iPSC models were not fully understood.
CRISPR correction rescues LQTS phenotypes in patient iPSCs; leaves open clinical translation pending in vivo validation.
AIMS: To establish a KCNQ1 mutant-specific induced pluripotent stem cell (iPSC) model of a Chinese inherited long QT syndrome (LQTS) patient and to explore the pathogenesis of KCNQ1 mutations. METHODS AND RESULTS: (1) Two patient-specific iPSC lines from the proband were obtained. (2) The experiments produced spontaneously beating cardiomyocytes (CMs) from patient iPSCs. Splicing mutation c. 605-2A > G in iPSC-derived cardiomyocytes (iPSC-CMs) resulted in the skipping of exon 4, exons 3-4, or exons 3-6 in KCNQ1 transcription what was observed in the patient's peripheral leukocytes. (3) Action potential duration (APD) at 50% and 90% repolarization (APD50 and APD90) of the patient's iPSC-derived ventricular-like-CMs was significantly longer than that of the control. Moreover, early after depolarization (EAD) and coupled beats were observed only in L1-iPSC-CMs. (4) A c.815G > A corrected iPSC line was obtained by using the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated protein 9 (Cas9) system. CONCLUSION: (1) Cardiomyocytes with spontaneous pulsation were successfully differentiated from LQTS patient-specific iPSC lines. (2) For KCNQ1 splicing mutations, there is a chance that splicing patterns in peripheral leukocytes are similar to that in patient iPSC-CMs. (3) The truncated KCNQ1 proteins induced by such splicing mutation might cause Iks decrease, which in turn produced APD prolongation and triggered activities. (4) Our data showed that CRISPR-Cas9 system could be used to rescue the LQTS-related mutations.
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Wang et al. (2019) studied Long QT syndrome (LQTS) (n=1). CRISPR-Cas9 gene correction vs. Uncorrected patient iPSC-derived cardiomyocytes was evaluated on Action potential duration (APD) and early afterdepolarization in iPSC-derived cardiomyocytes. The CRISPR-Cas9 system successfully corrected a KCNQ1 mutation in patient-derived induced pluripotent stem cells, reversing action potential prolongation and early afterdepolarizations in derived cardiomyocytes.
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