<i>ACTN2</i> Mutant Causes Proteopathy in Human iPSC-Derived Cardiomyocytes
Antonia T. L. Zech,
Maksymilian Prondzynski,
Sonia R. Singh,
Niels Pietsch,
Ellen Orthey,
Erda Alizoti,
Josefine Busch,
Alexandra Madsen,
Charlotta S. Behrens,
Moritz Meyer-Jens,
Giulia Mearini,
Marc D. Lemoine,
Elisabeth Krämer,
Diogo Mosqueira,
Sanamjeet Virdi,
Daniela Indenbirken,
Maren Depke,
Manuela Gesell Salazar,
Uwe Völker,
Ingke Braren,
William T. Pu,
Thomas Eschenhagen,
Elke Hammer,
Saskia Schlossarek,
Lucie Carrier
Affiliations
Antonia T. L. Zech
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Maksymilian Prondzynski
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Sonia R. Singh
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Niels Pietsch
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Ellen Orthey
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Erda Alizoti
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Josefine Busch
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Alexandra Madsen
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Charlotta S. Behrens
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Moritz Meyer-Jens
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Giulia Mearini
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Marc D. Lemoine
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Elisabeth Krämer
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Diogo Mosqueira
Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, UK
Sanamjeet Virdi
Heinrich-Pette-Institute, Leibniz Institute of Virology, 20246 Hamburg, Germany
Daniela Indenbirken
Heinrich-Pette-Institute, Leibniz Institute of Virology, 20246 Hamburg, Germany
Maren Depke
Department for Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, 17475 Greifswald, Germany
Manuela Gesell Salazar
Department for Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, 17475 Greifswald, Germany
Uwe Völker
Department for Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, 17475 Greifswald, Germany
Ingke Braren
Vector Facility, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
William T. Pu
Department of Cardiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
Thomas Eschenhagen
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Elke Hammer
Department for Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, 17475 Greifswald, Germany
Saskia Schlossarek
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Lucie Carrier
Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
Genetic variants in α-actinin-2 (ACTN2) are associated with several forms of (cardio)myopathy. We previously reported a heterozygous missense (c.740C>T) ACTN2 gene variant, associated with hypertrophic cardiomyopathy, and characterized by an electro-mechanical phenotype in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Here, we created with CRISPR/Cas9 genetic tools two heterozygous functional knock-out hiPSC lines with a second wild-type (ACTN2wt) and missense ACTN2 (ACTN2mut) allele, respectively. We evaluated their impact on cardiomyocyte structure and function, using a combination of different technologies, including immunofluorescence and live cell imaging, RNA-seq, and mass spectrometry. This study showed that ACTN2mut presents a higher percentage of multinucleation, protein aggregation, hypertrophy, myofibrillar disarray, and activation of both the ubiquitin-proteasome system and the autophagy-lysosomal pathway as compared to ACTN2wt in 2D-cultured hiPSC-CMs. Furthermore, the expression of ACTN2mut was associated with a marked reduction of sarcomere-associated protein levels in 2D-cultured hiPSC-CMs and force impairment in engineered heart tissues. In conclusion, our study highlights the activation of proteolytic systems in ACTN2mut hiPSC-CMs likely to cope with ACTN2 aggregation and therefore directs towards proteopathy as an additional cellular pathology caused by this ACTN2 variant, which may contribute to human ACTN2-associated cardiomyopathies.