scholarly journals Doxorubicin induces caspase-mediated proteolysis of KV7.1

2018 ◽  
Author(s):  
Anne Strigli ◽  
Christian Raab ◽  
Sabine Hessler ◽  
Tobias Huth ◽  
Adam J. T. Schuldt ◽  
...  
Keyword(s):  
Posttranslational Modification ◽  
Potassium Current ◽  
Induced Pluripotent Stem Cell ◽  
Neonatal Rat ◽  
Loss Of Function ◽  
Long Qt ◽  
Human Cardiomyocytes ◽  
Induced Pluripotent ◽  
Lqt Syndrome ◽  
Cardiac Potassium Current

AbstractThe voltage-gated potassium channel Kv7.1 (KCNQ1) co-assembles with KCNE1 to generate the cardiac potassium current IKs. Gain- and loss-of-function mutations in KCNQ1 are associated with atrial fibrillation and long-QT (LQT) syndrome, respectively, highlighting the importance of modulating IKS activity for proper cardiac function. On a post-translational level, IKS can be regulated by phosphorylation, ubiquitination and sumoylation. Here, we report proteolysis of Kv7.1 as a novel, irreversible posttranslational modification. The identification of two C-terminal fragments (CTF1 and CTF2) of Kv7.1 led us to identify an aspartate critical for the generation of CTF2 and caspases as responsible for mediating Kv7.1 proteolysis. Activating caspases by apoptotic stimuli significantly reduced Kv7.1/KCNE1 currents, which was abrogated in cells expressing caspase-resistant Kv7.1 D459A/KCNE1 channels. An increase in cleavage of Kv7.1 could be detected in the case of LQT mutation G460S, which is located adjacent to the cleavage site. Application of apoptotic stimuli or doxorubicin-induced cardiotoxicity provoked caspase-mediated cleavage of endogenous Kv7.1 in human cardiomyocytes. In summary, our findings establish caspases as novel regulatory components for modulating Kv7.1 activity which may have important implications for the molecular mechanism of doxorubicin-induced cardiotoxicity.Non-standard Abbreviations and AcronymsCamcalmodulinEBCequilibrium buffer contentLQT syndromelong QT syndromeNRVMNeonatal rat ventricular cardiomyocyteshiPSC-CMshuman induced pluripotent stem cell-derived cardiomyocytes

scholarly journals Large-Scale Simulation of the Phenotypical Variability Induced by Loss-of-Function Long QT Mutations in Human Induced Pluripotent Stem Cell Cardiomyocytes

2018 ◽  
Vol 19 (11) ◽  
pp. 3583 ◽  
Author(s):  
Michelangelo Paci ◽  
Simona Casini ◽  
Milena Bellin ◽  
Jari Hyttinen ◽  
Stefano Severi
Keyword(s):  
Action Potential ◽  
In Silico ◽  
Pluripotent Stem Cell ◽  
Large Scale ◽  
Induced Pluripotent Stem Cell ◽  
Loss Of Function ◽  
Prolonged Action ◽  
Long Qt ◽  
Induced Pluripotent

Loss-of-function long QT (LQT) mutations inducing LQT1 and LQT2 syndromes have been successfully translated to human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) used as disease-specific models. However, their in vitro investigation mainly relies on experiments using small numbers of cells. This is especially critical when working with cells as heterogeneous as hiPSC-CMs. We aim (i) to investigate in silico the ionic mechanisms underlying LQT1 and LQT2 hiPSC-CM phenotypic variability, and (ii) to enable massive in silico drug tests on mutant hiPSC-CMs. We combined (i) data of control and mutant slow and rapid delayed rectifying K+ currents, IKr and IKs respectively, (ii) a recent in silico hiPSC-CM model, and (iii) the population of models paradigm to generate control and mutant populations for LQT1 and LQT2 cardiomyocytes. Our four populations contain from 1008 to 3584 models. In line with the experimental in vitro data, mutant in silico hiPSC-CMs showed prolonged action potential (AP) duration (LQT1: +14%, LQT2: +39%) and large electrophysiological variability. Finally, the mutant populations were split into normal-like hiPSC-CMs (with action potential duration similar to control) and at risk hiPSC-CMs (with clearly prolonged action potential duration). At risk mutant hiPSC-CMs carried higher expression of L-type Ca2+, lower expression of IKr and increased sensitivity to quinidine as compared to mutant normal-like hiPSC-CMs, resulting in AP abnormalities. In conclusion, we were able to reproduce the two most common LQT syndromes with large-scale simulations, which enable investigating biophysical mechanisms difficult to assess in vitro, e.g., how variations of ion current expressions in a physiological range can impact on AP properties of mutant hiPSC-CMs.

scholarly journals Human Erbb2-induced Erk Activity Robustly Stimulates Cycling and Functional Remodeling of Rat and Human Cardiomyocytes

2020 ◽  
Author(s):  
Nicholas Strash ◽  
Sophia DeLuca ◽  
Geovanni Janer Carattini ◽  
Soon Chul Heo ◽  
Ryne Gorsuch ◽  
...  
Keyword(s):  
Ventricular Myocytes ◽  
Induced Pluripotent Stem Cell ◽  
Neonatal Rat ◽  
Mutant Form ◽  
Cardiac Tissues ◽  
Human Cardiomyocytes ◽  
Heart Repair ◽  
Induced Pluripotent ◽  
Species Specific

Multiple mitogenic pathways capable of promoting mammalian cardiomyocyte (CM) proliferation have been identified as potential candidates for functional heart repair following myocardial infarction. However, it is unclear whether the effects of these mitogens are species-specific and how they directly compare in the same cardiac setting. Here, we examined how CM-specific lentiviral expression of various candidate mitogens affects human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and neonatal rat ventricular myocytes (NRVMs) in vitro. In 2D-cultured CMs from both species, and in highly mature 3D-engineered cardiac tissues generated from NRVMs, a constitutively-active mutant form of the human gene Erbb2 (cahErbb2) was the most potent tested mitogen. Persistent expression of cahErbb2 induced CM proliferation, sarcomere loss, and remodeling of tissue structure and function, which were attenuated by small molecule inhibitors of Erk signaling. These results suggest transient activation of Erbb2/Erk axis in cardiomyocytes as a potential strategy for regenerative heart repair.

scholarly journals The Use of iPSC-Derived Cardiomyocytes and Optical Mapping for Erythromycin Arrhythmogenicity Testing

2019 ◽  
Author(s):  
A.D. Podgurskaya ◽  
V.A. Tsvelaya ◽  
M.M. Slotvitsky ◽  
E.V. Dementyeva ◽  
K.R. Valetdinova ◽  
...  
Keyword(s):  
Conduction Velocity ◽  
Potassium Current ◽  
Optical Mapping ◽  
Capture Rate ◽  
Torsade De Pointes ◽  
Induced Pluripotent Stem Cell ◽  
Experimental Models ◽  
Mapping Method ◽  
Neonatal Rat ◽  
Induced Pluripotent

AbstractErythromycin is an antibiotic that prolongs the QT-interval and causes Torsade de Pointes (TdP) by blocking the rapid delayed rectifying potassium current (IKr) without affecting either the slow delayed rectifying potassium current (IKs) or inward rectifying potassium current (IK1). Erythromycin exerts this effect in the range of 1.5 μM–100 μM. However, the mechanism of action underlying its cardiotoxic effect and its role in the induction of arrhythmias, especially in multicellular cardiac experimental models, remain unclear. In this study the re-entry formation, conduction velocity, and maximum capture rate were investigated in a monolayer of human induced pluripotent stem cell (iPSC)-derived cardiomyocytes from a healthy donor and in a neonatal rat ventricular myocyte (NRVM) monolayer using the optical mapping method under erythromycin concentrations of 15, 30, and 45 μM. In the monolayer of human iPSC-derived cardiomyocytes, the conduction velocity (CV) varied up to 12±9% at concentrations of 15–45 μM as compared with that of the control, whereas the maximum capture rate (MCR) declined substantially up to 28±12% (p < 0.05). In contrast, the tests on the NRVM monolayer showed no significant effect on the MCR. The results of the arrhythmogenicity test provided evidence for a “window” of concentrations of the drug (15 to 30 μM) at which the probability of re-entry increased.

scholarly journals Human Erbb2-induced Erk activity robustly stimulates cycling and functional remodeling of rat and human cardiomyocytes

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Nicholas Strash ◽  
Sophia DeLuca ◽  
Geovanni L Janer Carattini ◽  
Soon Chul Heo ◽  
Ryne Gorsuch ◽  
...  
Keyword(s):  
Ventricular Myocytes ◽  
Induced Pluripotent Stem Cell ◽  
Neonatal Rat ◽  
Mutant Form ◽  
Cardiac Tissues ◽  
Human Cardiomyocytes ◽  
Heart Repair ◽  
Induced Pluripotent ◽  
Species Specific

Multiple mitogenic pathways capable of promoting mammalian cardiomyocyte (CM) proliferation have been identified as potential candidates for functional heart repair following myocardial infarction. However, it is unclear whether the effects of these mitogens are species-specific and how they directly compare in the same cardiac setting. Here, we examined how CM-specific lentiviral expression of various candidate mitogens affects human induced pluripotent stem cell-derived CMs (hiPSC-CMs) and neonatal rat ventricular myocytes (NRVMs) in vitro. In 2D-cultured CMs from both species, and in highly mature 3D-engineered cardiac tissues generated from NRVMs, a constitutively-active mutant form of the human gene Erbb2 (cahErbb2) was the most potent tested mitogen. Persistent expression of cahErbb2 induced CM proliferation, sarcomere loss, and remodeling of tissue structure and function, which were attenuated by small molecule inhibitors of Erk signaling. These results suggest transient activation of Erbb2/Erk axis in cardiomyocytes as a potential strategy for regenerative heart repair.

scholarly journals Elucidating arrhythmogenic mechanisms of long-QT syndrome CALM1-F142L mutation in patient-specific induced pluripotent stem cell-derived cardiomyocytes

2017 ◽  
Vol 113 (5) ◽  
pp. 531-541 ◽  
Author(s):  
Marcella Rocchetti ◽  
Luca Sala ◽  
Lisa Dreizehnter ◽  
Lia Crotti ◽  
Daniel Sinnecker ◽  
...  
Keyword(s):  
Stem Cell ◽  
Long Qt Syndrome ◽  
Pluripotent Stem Cell ◽  
Induced Pluripotent Stem Cell ◽  
Patient Specific ◽  
Long Qt ◽  
Qt Syndrome ◽  
Induced Pluripotent

scholarly journals Patient-Specific Induced Pluripotent Stem-Cell Models for Long-QT Syndrome

2010 ◽  
Vol 363 (15) ◽  
pp. 1397-1409 ◽  
Author(s):  
Alessandra Moretti ◽  
Milena Bellin ◽  
Andrea Welling ◽  
Christian Billy Jung ◽  
Jason T. Lam ◽  
...  
Keyword(s):  
Stem Cell ◽  
Long Qt Syndrome ◽  
Pluripotent Stem Cell ◽  
Induced Pluripotent Stem Cell ◽  
Patient Specific ◽  
Cell Models ◽  
Long Qt ◽  
Qt Syndrome ◽  
Induced Pluripotent ◽  
Stem Cell Models

Abstract 142: Modeling Drug-Induced Long QT Syndrome with Patient-Specific Induced Pluripotent Stem Cell-Derived Cardiomyocytes

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Francesca Stillitano ◽  
Ioannis Karakikes ◽  
Chi-wai Kong ◽  
Brett Martinelli ◽  
Ronald Li ◽  
...  
Keyword(s):  
Stem Cell ◽  
Pluripotent Stem Cell ◽  
Induced Pluripotent Stem Cell ◽  
Patient Specific ◽  
Dependent Manner ◽  
Long Qt ◽  
Drug Induced ◽  
Qt Syndrome ◽  
Induced Pluripotent ◽  
Dose Dependent

Long QT syndrome (LQTS) is characterized by prolonged cardiac repolarization time and increased risk of ventricular arrhythmia. LQTS can be either inherited or induced notably after drugs intake. Mutations in genes encoding cardiac ion channels have been reported to underlie inherited LQTS. In contrast, drug-induced LQTS (diLQTS) most frequently arises from altered function of the hERG channel; the risk of developing diLQTS varies largely between subjects and most people who have life-threatening diLQTS have no known genetic risk factors. We investigated whether the susceptibility to develop diLQTS observed in vivo can be recapitulated in vitro using patient-specific induced pluripotent stem cell (iPSC) technology. We collected skin fibroblasts from ten subjects who developed significant diLQTS after administration of Sotalol and/or Erythromycin. Ten other individuals who displayed no changes in QT interval after administration of the same drugs, were selected. iPSC were generated by retroviral delivery of Oct4, Sox2, Nanog and Klf4 in 17 of the 20 individuals. We report preliminary results obtained from iPSC-derived cardiomyocytes (iPSC-CMs) of two subjects. All experiments were performed in a blinded fashion without knowledge of the associated clinical phenotype. Cardiac differentiation of iPSC resulted in the generation of spontaneously beating embryoid bodies. iPSC-CMs showed positive staining for TNNT2, ACTN2 and Cx43. Gene expression analysis confirmed the expression of NKX2.5, MLC2v, MYH6 and MYH7, and of the relevant KCNH2 gene. The two lines had similar basal electrophysiological properties as assessed by measurements of action potential (AP) by patch-clamp technique and extracellular field potentials (FP) using micro-electrode array (MEA). E4031, a classical HERG blocker, significantly prolonged the FP duration (FPD) in a dose-dependent manner in both lines (EC50: 30.19 and 51.57 respectively). When both Sotalol and Erythromicin were used, FPD was prolonged in one of the two samples in a dose-dependent manner (EC50Sotalol: 100; EC50Erythr: 9.64) while drug response was blunted in the other cell line. This study suggests that patient-specific iPSC can be used to model the functional abnormalities observed in acquired diLQTS.

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