Modeling reduced contractility and impaired desmosome assembly due to plakophilin-2 deficiency using isogenic iPS cell-derived cardiomyocytes

Loss-of-function mutations in PKP2, which encodes plakophilin-2, cause arrhythmogenic cardiomyopathy (AC). Restoration of deficient molecules can serve as upstream therapy, thereby requiring a human model that recapitulates disease pathology and provides distinct readouts in phenotypic analysis for proof of concept for gene replacement therapy. Here, we generated isogenic induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) with precisely adjusted expression of plakophilin-2 from a patient with AC carrying a heterozygous frameshift PKP2 mutation. After monolayer differentiation, plakophilin-2 deficiency led to reduced contractility, disrupted intercalated disc structures, and impaired desmosome assembly in iPSC-CMs. Allele-specific fluorescent labeling of endogenous DSG2 encoding desmoglein-2 in the generated isogenic lines enabled real-time desmosome-imaging under an adjusted dose of plakophilin-2. Adeno-associated virus-mediated gene replacement of PKP2 recovered contractility and restored desmosome assembly, which was sequentially captured by desmosome-imaging in plakophilin-2-deficient iPSC-CMs. Our isogenic set of iPSC-CMs recapitulates AC pathology and provides a rapid and convenient cellular platform for therapeutic development. [Display omitted] •Generation of isogenic iPSC-CMs with a precise dose of plakophilin-2•Modeling reduced contractility and impaired desmosome assembly using iPSC-CMs•Generation of isogenic iPSC-CMs for desmosome-imaging•Proof of concept of PKP2 replacement using isogenic plakophilin-2-deficient iPSC-CMs In this article, Higo and colleagues generate isogenic iPS cell-derived cardiomyocytes (iPSC-CMs) with precisely adjusted expression of PKP2, modeling reduced contractility and impaired desmosome assembly due to plakophilin-2 deficiency. PKP2 gene replacement recovered contractility and restored desmosome assembly, which was sequentially captured by desmosome imaging. The isogenic iPSC-CMs recapitulate the pathology of arrhythmogenic cardiomyopathy and provide a rapid and convenient cellular platform for therapeutic development.