Full-length dystrophin deficiency leads to contractile and calcium transient defects in human engineered heart tissues

Cardiomyopathy is currently the leading cause of death for patients with Duchenne muscular dystrophy (DMD), a severe neuromuscular disorder affecting young boys. Animal models have provided insight into the mechanisms by which dystrophin protein deficiency causes cardiomyopathy, but there remains a...

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Bibliographic Details
Published in:Journal of tissue engineering 2022, Vol.13, p.20417314221119628
Main Authors: Bremner, Samantha B, Mandrycky, Christian J, Leonard, Andrea, Padgett, Ruby M, Levinson, Alan R, Rehn, Ethan S, Pioner, J Manuel, Sniadecki, Nathan J, Mack, David L
Format: Article
Language:English
Subjects:
Actin
Animal models
Calcium (extracellular)
Calcium homeostasis
Calcium ions
Cardiac muscle
Cardiomyocytes
Cardiomyopathy
CRISPR
Duchenne's muscular dystrophy
Dystrophin
Dystrophy
Extracellular matrix
Gene regulation
Genes
Homeostasis
Membrane potential
Muscle contraction
Muscles
Muscular dystrophy
Original
Phenotypes
Pluripotency
Protein deficiency
Proteins
Stem cells
Target recognition
Therapeutic targets
Transcriptomics
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Summary:Cardiomyopathy is currently the leading cause of death for patients with Duchenne muscular dystrophy (DMD), a severe neuromuscular disorder affecting young boys. Animal models have provided insight into the mechanisms by which dystrophin protein deficiency causes cardiomyopathy, but there remains a need to develop human models of DMD to validate pathogenic mechanisms and identify therapeutic targets. Here, we have developed human engineered heart tissues (EHTs) from CRISPR-edited, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) expressing a truncated dystrophin protein lacking part of the actin-binding domain. The 3D EHT platform enables direct measurement of contractile force, simultaneous monitoring of Ca2+ transients, and assessment of myofibril structure. Dystrophin-mutant EHTs produced less contractile force as well as delayed kinetics of force generation and relaxation, as compared to isogenic controls. Contractile dysfunction was accompanied by reduced sarcomere length, increased resting cytosolic Ca2+ levels, delayed Ca2+ release and reuptake, and increased beat rate irregularity. Transcriptomic analysis revealed clear differences between dystrophin-deficient and control EHTs, including downregulation of genes related to Ca2+ homeostasis and extracellular matrix organization, and upregulation of genes related to regulation of membrane potential, cardiac muscle development, and heart contraction. These findings indicate that the EHT platform provides the cues necessary to expose the clinically-relevant, functional phenotype of force production as well as mechanistic insights into the role of Ca2+ handling and transcriptomic dysregulation in dystrophic cardiac function, ultimately providing a powerful platform for further studies in disease modeling and drug discovery.
ISSN:2041-7314
2041-7314
DOI:10.1177/20417314221119628