Functional abnormalities in induced Pluripotent Stem Cell-derived cardiomyocytes generated from titin-mutated patients with dilated cardiomyopathy

PLoS One. 2018 Oct 17;13(10):e0205719. doi: 10.1371/journal.pone.0205719. eCollection 2018.

Abstract

Aims: Dilated cardiomyopathy (DCM), a myocardial disorder that can result in progressive heart failure and arrhythmias, is defined by ventricular chamber enlargement and dilatation, and systolic dysfunction. Despite extensive research, the pathological mechanisms of DCM are unclear mainly due to numerous mutations in different gene families resulting in the same outcome-decreased ventricular function. Titin (TTN)-a giant protein, expressed in cardiac and skeletal muscles, is an important part of the sarcomere, and thus TTN mutations are the most common cause of adult DCM. To decipher the basis for the cardiac pathology in titin-mutated patients, we investigated the hypothesis that induced Pluripotent Stem Cell (iPSC)-derived cardiomyocytes (iPSC-CM) generated from patients, recapitulate the disease phenotype. The hypothesis was tested by 3 Aims: (1) Investigate key features of the excitation-contraction-coupling machinery; (2) Investigate the responsiveness to positive inotropic interventions; (3) Investigate the proteome profile of the AuP cardiomyocytes using mass-spectrometry (MS).

Methods and results: iPSC were generated from the patients' skin fibroblasts. The major findings were: (1) Sarcomeric organization analysis in mutated iPSC-CM showed defects in assembly and maintenance of sarcomeric structure. (2) Mutated iPSC-CM exhibited diminished inotropic and lusitropic responses to β-adrenergic stimulation with isoproterenol, increased [Ca2+]out and angiotensin-II. Additionally, mutated iPSC-CM displayed prolonged recovery in response to caffeine. These findings may result from defective or lack of interactions of the sarcomeric components with titin through its kinase domain which is absent in the mutated cells.

Conclusions: These findings show that the mutated cardiomyocytes from DCM patients recapitulate abnormalities of the inherited cardiomyopathies, expressed as blunted inotropic response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cardiomyopathy, Dilated / genetics*
  • Cardiomyopathy, Dilated / pathology
  • Cell Differentiation / genetics*
  • Connectin / genetics*
  • Excitation Contraction Coupling / genetics
  • Humans
  • Induced Pluripotent Stem Cells / physiology
  • Isoproterenol / pharmacology
  • Male
  • Mutation
  • Myocardial Contraction / drug effects
  • Myocardial Contraction / genetics*
  • Myocytes, Cardiac / pathology*
  • Myocytes, Cardiac / physiology
  • Proteome

Substances

  • Connectin
  • Proteome
  • TTN protein, human
  • Isoproterenol

Grant support

This work was supported by the Israel Science Foundation (ISF) [grant number 292/13]; the Israeli Ministry of Science, Technology and Space [grant number 7-10772]; the Niedersachsen Ministry of Science and Culture [grant number 11-76251-99-16/14]; and the DZHK (German Centre for Cardiovascular Research - partner site Munich Heart Alliance – grant number 81Z7600671).