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Circ Cardiovasc Genet. 2017 Oct;10(5). pii: e001755. doi: 10.1161/CIRCGENETICS.117.001755.

Characterization of a Human Induced Pluripotent Stem Cell-Derived Cardiomyocyte Model for the Study of Variant Pathogenicity: Validation of a KCNJ2 Mutation.

Author information

1
From the Research Center (R.G., N.E.K., M.-A.C., C.B., A.A., N.E., G.B., L.V., L.R., F.L., B.M., L.R., P.G., M.T., C.F., J.D.R.) and Cardiovascular Genetics Center (L. Robb, L. Rivard, M.T.), Montreal Heart Institute, Quebec, Canada; and Department of Medicine (R.G., M.-A.C., B.M., L.R., M.T., J.D.R.) and Faculty of Pharmacy (N.E.K., C.F.), Université de Montréal, Quebec, Canada.
2
From the Research Center (R.G., N.E.K., M.-A.C., C.B., A.A., N.E., G.B., L.V., L.R., F.L., B.M., L.R., P.G., M.T., C.F., J.D.R.) and Cardiovascular Genetics Center (L. Robb, L. Rivard, M.T.), Montreal Heart Institute, Quebec, Canada; and Department of Medicine (R.G., M.-A.C., B.M., L.R., M.T., J.D.R.) and Faculty of Pharmacy (N.E.K., C.F.), Université de Montréal, Quebec, Canada. john.david.rioux@umontreal.ca celine.fiset@umontreal.ca.

Abstract

BACKGROUND:

Long-QT syndrome is a potentially fatal condition for which 30% of patients are without a genetically confirmed diagnosis. Rapid identification of causal mutations is thus a priority to avoid at-risk situations that can lead to fatal cardiac events. Massively parallel sequencing technologies are useful for the identification of sequence variants; however, electrophysiological testing of newly identified variants is crucial to demonstrate causality. Long-QT syndrome could, therefore, benefit from having a standardized platform for functional characterization of candidate variants in the physiological context of human cardiomyocytes.

METHODS AND RESULTS:

Using a variant in Kir2.1 (Gly52Val) revealed by whole-exome sequencing in a patient presenting with symptoms of long-QT syndrome as a proof of principle, we demonstrated that commercially available human induced pluripotent stem cell-derived cardiomyocytes are a powerful model for screening variants involved in genetic cardiac diseases. Immunohistochemistry experiments and whole-cell current recordings in human embryonic kidney cells expressing the wild-type or the mutant Kir2.1 demonstrated that Kir2.1-52V alters channel cellular trafficking and fails to form a functional channel. Using human induced pluripotent stem cell-derived cardiomyocytes, we not only confirmed these results but also further demonstrated that Kir2.1-52V is associated with a dramatic prolongation of action potential duration with evidence of arrhythmic activity, parameters which could not have been studied using human embryonic kidney cells.

CONCLUSIONS:

Our study confirms the pathogenicity of Kir2.1-52V in 1 patient with long-QT syndrome and also supports the use of isogenic human induced pluripotent stem cell-derived cardiomyocytes as a physiologically relevant model for the screening of variants of unknown function.

KEYWORDS:

arrhythmias, cardiac; immunohistochemistry; induced pluripotent stem cells; long QT syndrome; mutation

PMID:
29021306
DOI:
10.1161/CIRCGENETICS.117.001755
[Indexed for MEDLINE]

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