Life science
Medicine / Healthcare, Drug development

Generation of human disease model recapitulating
inherited cardiomyopathy
Department of Medical Therapeutics for Heart Failure, Graduate School of Medicine
SA Associate Professor Shuichiro Higo
Researchmap https://researchmap.jp/s.higo

Life science

Abstract
Mutations in desmosome genes cause arrhythmogenic cardiomyopathy, mainly in an autosomal dominant manner. Here, we
identified a desmoglein-2-deficient cardiomyopathy caused by rarehomozygous stop-gain mutation in DSG2 (R119X) in a patient withsevere biventricular heart failure. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) generated from the patient recapitulated arrhythmia, tissue fragility and decreased contractile
force. These phenotypes were corrected by restored expression ofdesmoglein-2 mediated by genome editing or gene replacementby adeno-associated virus. The recapitulation and correction of thedisease phenotype using isogenic iPSC-CMs provides evidence
for precision medicine and the proof of concept for gene replacement therapy.

▍ Significance of the research and Future perspective
In 2021, more than 900 patients with advanced heart failure arewaiting for heart transplantation in Japan. Dilated cardiomyopathy
is a major cause of advanced heart failure. Recapitulation andcorrection of the disease phenotype of desmoglein-2-deficient
cardiomyopathy using iPSC-CMs provide evidence for precision
medicine and the proof of concept for gene replacement therapy.

Mainfigure▍ Background & Results
Desmoglein-2, encoded by DSG2, maintains the structural integrity of tissues, including heart. Genetic mutations in DSG2 cause
arrhythmogenic cardiomyopathy, mainly in an autosomal dominantmanner. The purpose of this study was phenotypic recapitulationand correction of desmoglein-2-deficient cardiomyopathy using
induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs).
We identified a homozygous stop-gain mutation in DSG2 (R119X)
that led to complete desmoglein-2 deficiency in a patient with severe biventricular heart failure. The patient’s ventricular myocardium was analyzed histologically. Phenotype analysis was performedon patient-derived iPSC-CMs with or without restored desmoglein-2
expression mediated by CRISPR/Cas9 genome editing or gene replacement by adeno-associated virus (AAV). Immunohistochemicaland electron microscopic analysis revealed abnormal deposition ofdesmosome proteins, disrupted intercalated disc structures, andaggregated cytoplasmic desmosomes in the patient’s left ventricular myocardium. iPSCs were generated from the patient (R119X-iPSC), and R119X mutation was heterozygously corrected to thenormal allele via homology-directed repair (HDR-iPSC). Multiple
electrode array analysis detected abnormal excitation in R119X-iPSC-CMs but not in HDR-iPSC-CMs. Micro force test detected tissue
fragility and weak maximum forces in 3-dimensional self-organizedtissue rings (SOTRs) from R119X-iPSC-CMs. Notably, these phenotypes were significantly recovered in SOTRs from HDR-iPSC-CMs.
The myocardial fiber structures in R119X-iPSC-CMs were severely
aberrant, and electron microscopic analysis revealed disrupted
desmosomes in R119X-iPSC-CMs. AAV-mediated replacement of
DSG2 significantly recovered the contraction force in SOTRs generated from R119X-iPSC-CMs.
Conclusions: Recapitulation and correction of the disease phenotype of desmoglein-2-deficient cardiomyopathy using iPSC-CMs
provides evidence for precision medicine and the proof of concept
for gene replacement therapy.

補足図表①

Severely disrupted intercalated disc structures in left ventricularmyocardium from desmoglein-2-deficient cardiomyopathy

1 µm

補足図表
②

Restoration of desmoglein-2 recovered
micro force in 3D tissue rings

R119X

HDR

Micro force(μN)

3D tissue rings

50μN

R119X HDR5s

P a t e n t Japanese Patent Application No. 2020-44996, PCT/JP2021/10137
Shiba M, Higo S, Hikoso S, Sakata Y. Phenotypic recapitulation and correction of desmoglein-2-deficient cardiomyopathy using human-induced pluripoTr e a t i s etent stem cell-derived cardiomyocytes. Hum Mol Genet. 2021 Jul 9; 30(15): 1384-1397. doi: 10.1093/hmg/ddab127.
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L http://www.cardiology.med.osaka-u.ac.jp/?page_id=37187
K e y w o r d dilated cardiomyopathy, desmoglein-2, human induced pluripotent stem cell-derived cardiomyocytes, genome editing, adeno-associated virus