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Heart Rhythm. 2018 Oct;15(10):1566-1574. doi: 10.1016/j.hrthm.2018.05.028. Epub 2018 May 29.

Complex aberrant splicing in the induced pluripotent stem cell-derived cardiomyocytes from a patient with long QT syndrome carrying KCNQ1-A344Aspl mutation.

Author information

1
Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Japan; Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Shogoin, Sakyo-ku, Kyoto, Japan.
2
Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Shogoin, Sakyo-ku, Kyoto, Japan. Electronic address: makiyama@kuhp.kyoto-u.ac.jp.
3
Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Shogoin, Sakyo-ku, Kyoto, Japan.
4
Center for iPS Cell Research and Application, Institute for Integrated Cell-Material Sciences, Kyoto University, Shogoin, Sakyo-ku, Kyoto, Japan.
5
Department of Pediatrics, Tazuke Kofukai Foundation, Medical Research Institute, Kitano Hospital, Ohgimachi, Kita-ku, Osaka, Japan.
6
Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Japan; Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Fujishiro-dai, Suita, Osaka, Japan.
7
Center for iPS Cell Research and Application, Institute for Integrated Cell-Material Sciences, Kyoto University, Shogoin, Sakyo-ku, Kyoto, Japan. Electronic address: yoshinor@cira.kyoto-u.ac.jp.
8
Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Japan.

Abstract

BACKGROUND:

Long QT syndrome type 1 (LQT1) is caused by mutations in KCNQ1, which encodes the α subunit of the slow delayed rectifier potassium current channel. We previously reported that a synonymous mutation, c.1032G>A, p.A344Aspl, in KCNQ1 is most commonly identified in genotyped patients with LQT1 in Japan and the aberrant splicing was analyzed in the lymphocytes isolated from patients' blood samples. However, the mechanisms underlying the observed processes in human cardiomyocytes remain unclear.

OBJECTIVE:

The purpose of this study was to establish and analyze patient-specific human-induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) model carrying KCNQ1-A344Aspl.

METHODS:

We generated hiPSCs from the peripheral blood mononuclear cells obtained from a patient with LQT1 carrying KCNQ1-A344Aspl. Using the differentiated cardiomyocytes, we analyzed splicing variants and performed electrophysiology studies.

RESULTS:

We identified 7 aberrant RNA variants in A344Aspl hiPSC-CMs, which were more complex compared with those in peripheral lymphocytes. Multielectrode array analysis revealed that 1 μM isoproterenol significantly prolonged the duration of the corrected field potential in A344Aspl hiPSC-CMs as compared with that in control hiPSC-CMs. In addition, 100 nM E-4031, which inhibits the rapid component of the delayed rectifier potassium current, was shown to induce early afterdepolarization-like waveforms in A344Aspl hiPSC-CMs. Action potential durations (APDs) did not significantly differ between the hiPSC-CM groups. After administering 500 nM isoproterenol, APDs of A344Aspl hiPSC-CMs were significantly longer than those of the controls. (R)-N-(4-(4-Methoxyphenyl)thiazol-2-yl)-1-tosylpiperidine-2-carboxamide and phenylboronic acid, slow delayed rectifier potassium current activators, ameliorated the APDs of hiPSC-CMs.

CONCLUSION:

We identified complex aberrant messenger RNA variants in the A344Aspl hiPSC-CM model and successfully recapitulated the clinical phenotypes of the patient with concealed LQT1. This model allows the investigation of the underlying mechanisms and development of novel therapies.

KEYWORDS:

Aberrant splicing; I(Ks) activator; Induced pluripotent stem cell; KCNQ1; Long QT syndrome

PMID:
29857160
DOI:
10.1016/j.hrthm.2018.05.028
[Indexed for MEDLINE]

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