Increase in Ca2+-Activated cAMP/PKA Signaling Prevents Hydroxychloroquine-Induced Bradycardia of the Cardiac Pacemaker

Segal, Sofia; Arbel-Ganon, Limor; Mazgaoker, Savyon; Davoodi, Moran; Yaniv, Yael

doi:10.3389/fphys.2022.839140

Cited by 4 publications

(4 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given the role that L-type calcium current plays in excitation-contraction coupling, as major trigger for calciuminduced calcium release from the sarcoplasmic reticulum, a decrease in calcium influx via L-type calcium channels could significantly affect intracellular calcium concentration and impair cardiac contraction (Eisner et al, 2017). The recent observation that HCQ decreases total calcium influx and calcium transient magnitude in cardiomyocytes (Oguntuyo et al, 2022;Segal et al, 2022), together with HCQ and AZM effect on calcium transient upstroke velocity in human induced pluripotent stem cell-derived cardiomyocytes (Charrez et al, 2021), further supports the ability of both drugs to reduce intracellular calcium concentration and affect contractility.…”

Section: The Calcium Channel Agonist Bay K8644 Prevents and Reverses ...mentioning

confidence: 99%

Hydroxychloroquine and azithromycin alter the contractility of living porcine heart slices

Ross

İpek

et al. 2023

Front. Pharmacol.

View full text Add to dashboard Cite

The cardiotoxicity risk of hydroxychloroquine (HCQ) and azithromycin (AZM) has been the subject of intensive research triggered by safety concerns in COVID-19 patients. HCQ and AZM have been associated with QT interval prolongation and drug-induced arrhythmias, however other cardiotoxicity mechanisms remain largely unexplored. Our group has pioneered the living heart slice preparation, an ex-vivo platform that maintains native cardiac tissue architecture and physiological electrical and contractile properties. Here, we evaluated the cardiotoxic effect of HCQ and AZM applied alone or in combination on cardiac contractility by measuring contractile force and contraction kinetics in heart slices prepared from porcine hearts. Our results show that clinically relevant concentrations of HCQ monotherapy (1–10 µM) reduced contractile force and contraction kinetics in porcine slices in a dose-dependent manner. However, AZM monotherapy decreased contractile force and contraction kinetics only at higher concentrations (30 µM). Combination of HCQ and AZM induced a dose-dependent effect similar to HCQ alone. Furthermore, pre-treating porcine heart slices with the L-type calcium channel agonist Bay K8644 prevented the effect of both drugs, while administration of Bay K8644 after drugs interventions largely reversed the effects, suggesting a mechanism involving inhibition of L-type calcium channels. These findings indicate that HCQ and AZM alter cardiac function beyond QT prolongation with significant contractile dysfunction in intact cardiac tissue. Our porcine heart slices provide a powerful platform to investigate mechanisms of drug cardiotoxicity.

show abstract

Section: The Calcium Channel Agonist Bay K8644 Prevents and Reverses ...mentioning

confidence: 99%

Hydroxychloroquine and azithromycin alter the contractility of living porcine heart slices

Ross

İpek

et al. 2023

Front. Pharmacol.

View full text Add to dashboard Cite

show abstract

“…To demonstrate that LCR characteristics are affected by changes in the beating rate, hiPSC-CMs were treated with HCQ, which causes bradycardia ( Capel et al, 2015 ). We recently showed that HCQ-induced bradycardia was caused by a direct effect on the M clock and an indirect effect on the Ca 2+ clock ( Segal et al, 2022 ). Fig.…”

Section: Resultsmentioning

confidence: 99%

cAMP-PKA signaling modulates the automaticity of human iPSC-derived cardiomyocytes

Mazgaoker

Weiser-Bitoun

Brosh

et al. 2022

Journal of General Physiology

Self Cite

View full text Add to dashboard Cite

Human-induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) have been used to screen and characterize drugs and to reveal mechanisms underlying cardiac diseases. However, before hiPSC-CMs can be used as a reliable experimental model, the physiological mechanisms underlying their normal function should be further explored. Accordingly, a major feature of hiPSC-CMs is automaticity, which is regulated by both Ca2+ and membrane clocks. To investigate the mechanisms coupling these clocks, we tested three hypotheses: (1) normal automaticity of spontaneously beating hiPSC-CMs is regulated by local Ca2+ releases (LCRs) and cAMP/PKA-dependent coupling of Ca2+ clock to M clock; (2) the LCR period indicates the level of crosstalk within the coupled-clock system; and (3) perturbing the activity of even one clock can lead to hiPSC-CM–altered automaticity due to diminished crosstalk within the coupled-clock system. By measuring the local and global Ca2+ transients, we found that the LCRs properties are correlated with the spontaneous beat interval. Changes in cAMP-dependent coupling of the Ca2+ and M clocks, caused by a pharmacological intervention that either activates the β-adrenergic or cholinergic receptor or upregulates/downregulates PKA signaling, affected LCR properties, which in turn altered hiPSC-CMs automaticity. Clocks’ uncoupling by attenuating the pacemaker current If or the sarcoplasmic reticulum Ca2+ kinetics, decreased hiPSC-CMs beating rate, and prolonged the LCR period. Finally, LCR characteristics of spontaneously beating (at comparable rates) hiPSC-CMs and rabbit SAN are similar. In conclusion, hiPSC-CM automaticity is controlled by the coupled-clock system whose function is mediated by Ca2+-cAMP-PKA signaling.

show abstract

“…Single, spindle-shaped SANCs were isolated from the hearts of white New Zealand rabbits weighing 2.3-2.7 kg, as previously described [8,9]. Briefly, rabbits were sedated with ketamine and xylazine (0.1 mL/kg each) and anesthetized with sodium pentobarbital (200 mg/mL) diluted with heparin, administered through an intravenous cannula.…”

Section: San Cell Isolation and Culturementioning

confidence: 99%

“…Ca 2+ cycling in single spontaneously beating SANCs was recorded by monitoring the fluorescence of the Ca 2+ indicator dye, Fluo-4 AM (Thermo Fisher Scientific, Waltham, MA, USA), using a LSM880 confocal microscope, as previously described [8]. SANCs were loaded with 5 µM Fluo-4 AM for 20 min, in the dark, at room temperature, and then washed with a 37 • C HEPES solution (140 mM NaCl, 5.4 mM KCl, 2 mM MgCl 2 , 5 mM HEPES, 1.8 mM CaCl 2 and 10 mM glucose, titrated to pH 7.4 with NaOH).…”

Section: Ca 2+ Imaging and Measurementsmentioning

confidence: 99%

Ca2+-Driven Selectivity of the Effect of the Cardiotonic Steroid Marinobufagenin on Rabbit Sinoatrial Node Function

Segal

Yaniv

2023

Cells

Self Cite

View full text Add to dashboard Cite

The synergy between Na+-K+ pumps, Na+-Ca2+ exchangers, membrane currents and the sarcoplasmic reticulum (SR) generates the coupled-clock system, which governs the spontaneous electrical activity of heart sinoatrial node cells (SANCs). Ca2+ mediates the degree of clock coupling via local Ca2+ release (LCR) from the SR and activation of cAMP/PKA signaling. Marinobufagenin (MBG) is a natural Na+-K+ pump inhibitor whose effect on SANCs has not been measured before. The following two hypotheses were tested to determine if and how MBG mediates between the Na+-K+ pump and spontaneous SAN activity: (i) MBG has a distinct effect on beat interval (BI) due to variable effects on LCR characteristics, and (ii) Ca2+ is an important mediator between MBG and SANC activity. Ca2+ transients were measured by confocal microscopy during application of increasing concentrations of MBG. To further support the hypothesis that Ca2+ mediates between MBG and SANC activity, Ca2+ was chelated by the addition of BAPTA. Dose response tests found that 100 nM MBG led to no change in BI in 6 SANCs (no BI change group), and to BI prolongation in 10 SANCs (BI change group). At the same concentration, the LCR period was prolonged in both groups, but more significantly in the BI change group. BAPTA-AM prolonged the BI in 12 SANCs. In the presence of BAPTA, 100 nM MBG had no effect on SANC BI or on the LCR period. In conclusion, the MBG effects on SANC function are mediated by the coupled clock system, and Ca2+ is an important regulator of these effects.

show abstract

Increase in Ca2+-Activated cAMP/PKA Signaling Prevents Hydroxychloroquine-Induced Bradycardia of the Cardiac Pacemaker

Cited by 4 publications

References 31 publications

Hydroxychloroquine and azithromycin alter the contractility of living porcine heart slices

Hydroxychloroquine and azithromycin alter the contractility of living porcine heart slices

cAMP-PKA signaling modulates the automaticity of human iPSC-derived cardiomyocytes

Ca2+-Driven Selectivity of the Effect of the Cardiotonic Steroid Marinobufagenin on Rabbit Sinoatrial Node Function

Contact Info

Product

Resources

About