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Identification of PITX2 as a novel factor in arrhythmogenic cardiomyopathy pathogenesis [KI]

ABSTRACT: In this study, we identified a novel heterozygous variant within DSP (c.3562T>C) in a patient diagnosed with ACM. Using CRISPR/Cas9 we corrected patient-derived human induced pluripotent stem cells (hiPSC) and created a knock-in (KI) hiPSC line with the same mutation. Compared to wildtype cardiomyocytes, we observed a prolonged action potential duration (APD) and reduced expression of desmosomal components, which was paralleled by abnormal levels of essential cardiac ion channels. Strikingly, the transcription factor paired-like homeodomain 2 (PITX2), which acts as a repressor of ion channel-related genes, was induced in these cells. Together, we identified PITX2 as a potential missing link between mutations in DSP and the cardiac conductance abnormalities often seen in these patients.

ORGANISM(S): Homo sapiens

PROVIDER: GSE208212 | GEO | 2023/03/02

REPOSITORIES: GEO

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Identification of PITX2 as a novel factor in arrhythmogenic cardiomyopathy pathogenesis [patient line]

Project description:In this study, we identified a novel heterozygous variant within DSP (c.3562T>C) in a patient diagnosed with ACM. Using CRISPR/Cas9 we corrected patient-derived human induced pluripotent stem cells (hiPSC) and created a knock-in (KI) hiPSC line with the same mutation. Compared to wildtype cardiomyocytes, we observed a prolonged action potential duration (APD) and reduced expression of desmosomal components, which was paralleled by abnormal levels of essential cardiac ion channels. Strikingly, the transcription factor paired-like homeodomain 2 (PITX2), which acts as a repressor of ion channel-related genes, was induced in these cells. Together, we identified PITX2 as a potential missing link between mutations in DSP and the cardiac conductance abnormalities often seen in these patients.

2023-03-02 | GSE208213 | GEO

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A Cellular Atlas of Pitx2-Dependent Cardiac Development

Project description:The Pitx2 gene encodes a homeobox transcription factor that is required for mammalian development. Disruption of PITX2 expression in humans causes congenital heart diseases and is associated with atrial fibrillation (AF), however, the cellular and molecular processes dictated by Pitx2 during cardiac ontogeny remain unclear. To characterize the role of Pitx2 during murine heart development we sequenced over 75,000 single cardiac cell transcriptomes between two key developmental timepoints in control and Pitx2-null embryos. We uncovered that cardiac cell composition was dramatically altered in mutants at both E10.5 and E13.5. Interestingly, the differentiation dynamics of both anterior and posterior second heart field derived progenitor cells were disrupted in Pitx2 mutants. We also uncovered evidence for defects in left-right asymmetry within atrial cardiomyocyte populations. Furthermore, we were able to detail defects in cardiac outflow tract and valve development associated with Pitx2. Our findings offer insight into Pitx2 biology and provide a compilation of gene expression signatures for further detailing the complexities of heart development that will serve as the foundation for future studies of cardiac morphogenesis, congenital heart disease, and arrhythmogenesis.

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