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allied
academies
Journal of Nutrition and Human Health | Volume 2
&
October 29-30, 2018 | London, UK
Joint Event
Nutrition and Fitness
16
th
International Conference on
3
rd
World Congress on
Card i o l ogy
Notes:
Ofer Binah
Technion-Israel Institute of Technology, Israel
Molecular characterization and functional properties of induced pluripotent stem
cells-derived cardiomyocytes from healthy and diseased individuals. Models for
investigating inherited cardiac diseases
Introduction:
Duchenne Muscular Dystrophy (DMD) caused by
mutations in the DMD gene encoding the dystrophin protein, is
anX-linkeddisease affecting boys and teenagers and rarely adult
heterozygous females. DMD is characterized by progressive
muscle degeneration and weakness, loss of ambulation and
death by the late 20’s or early 30’s. Dilated cardiomyopathy
(DCM) is a major cause of morbidity and mortality in DMD
patients.
Hypothesis:
Inducedpluripotent stemcell-derivedcardiomyocytes
(iPSC-CMs) generated from the DMD patients exhibit intracellular
[Ca2+]i handling andmechanical abnormalities. Our goal was to
decipher themechanical andmolecular mechanisms underlying
the abnormal [Ca2+]i handling and contraction in DMD patients.
Methods:
Dystrophin‐mutated iPSC-CMs were generated from
male and female DMD patients. To test the hypothesis, [Ca2+]i
transientsandcontractionswererecorded fromstimulated iPSC-
CMs clusters using fura-2 fluorescence and video edge detector,
in the absence and presence of the β-adrenergic agonist
isoproterenol, which increases SR Ca2+ release through PKA-
regulated Ryanodine (RyR2) channels. Specifically, wemeasured
the inotropic response to 10-9-10-6 M of isoproterenol using
the IonOptix calcium and contractility system. In addition,
metabolic indices were evaluated using liquid chromatography
followed by mass spectrometry and Seahorse XF analyser.
Results:
Our experiments showed a concentration-dependent
positive inotropic and lusitropic effects in healthy iPSC-CMs, on
both [Ca2+]i transient and contraction parameters. In contrast,
compared to healthy iPSC-CMs, the female and male DMD
iPSC-CMs displayed a markedly depressed inotropic response
to isoproterenol. To decipher the underlying mechanism, we
determined SR Ca2+ release and capacity in DMD iPSC-CMs by
means of a brief application of caffeine (10 mM) which serves
as an opener of the RyR2 channel. In control iPSC-CMs, caffeine
caused an abrupt increase in [Ca2+]i, followed by a gradual
decline in [Ca2+]i level. In marked contrast to control iPSC-CMs,
the male DMD iPSC-CMs exhibited a much shorter response to
caffeine, while only 50%of the female DMD iPSC-CMs displayed
abnormal [Ca2+]i handling in response to caffeine. The caffeine-
induced Ca2+ signal area of DMD iPSC-CMs (male and 50%
of female) was smaller than control. In addition, the caffeine-
induced Ca2+ signal amplitude of DMD iPSC-CM (female) was
significantly smaller than control. In addition, Seahorse XF
analyser demonstrated decreased oxidative phosphorylation
accompanied by a correlated increase in glycolysis in DMD
iPSC-CMs. Accordingly, mass spectrometry analysis showed a
dramatic fall in phosphocreatine levels in DMD iPSC-CMs.
Conclusion:
DMD iPSC-CMs exhibit an attenuatedβ-adrenergic
inotropicresponse,metabolicdeficitsandreducedenergystores.
Speaker Biography
Ofer Binah is Chair of Physiology, Biophysics and Systems Biology, at the Ruth & Bruce
Rappaport Faculty of Medicine, Technion, Israel. He is a cardiac physiologist working for
the past 33 years on research topics related to cellular electrophysiology, mechanics,
signalling pathways and arrhythmias. In addition, he investigated the cellular mechanisms
whereby cytotoxic T lymphocytes destroy cardiomyocytes in the course of heart transplant
rejection and inflammatory heart diseases. Since 2001 he is investigating the functional
properties of human embryonic stem cell-derived cardiomyocytes, and have published
several papers in this area. Over 10 years ago he has begun investigating iPSC-derived
cardiomyocytes generated from both dermal fibroblasts and keratinocytes, from healthy
volunteers and from patients with inherited cardiac pathologies, including inherited
arrhythmias and cardiomyopathies such as Duchenne Muscular Dystrophy.
e:
binah@technion.ac.il