Prolonged β-adrenergic stimulation disperses ryanodine receptor clusters in cardiomyocytes
- Oslo University Hospital, Norway
- Simula Reseach Laboratory, Norway
- University of Oslo, Norway
- Baylor College of Medicine, United States
- University of Exeter, United Kingdom
Abstract
Ryanodine Receptors (RyRs) exhibit dynamic arrangements in cardiomyocytes, and we previously showed that 'dispersion' of RyR clusters disrupts Ca2+ homeostasis during heart failure (HF) (Kolstad et al., eLife, 2018). Here, we investigated whether prolonged β-adrenergic stimulation, a hallmark of HF, promotes RyR cluster dispersion, and examined the underlying mechanisms. We observed that treatment of healthy rat cardiomyocytes with isoproterenol for 1 hour triggered progressive fragmentation of RyR clusters. Pharmacological inhibition of CaMKII reversed these effects, while cluster dispersion was reproduced by specific activation of CaMKII, and in mice with constitutively active Ser2814-RyR. A similar role of protein kinase A (PKA) in promoting RyR cluster fragmentation was established by employing PKA activation or inhibition. Progressive cluster dispersion was linked to declining Ca2+ spark fidelity and magnitude, and slowed release kinetics from Ca2+ propagation between more numerous RyR clusters. In healthy cells, this served to dampen the stimulatory actions of β-adrenergic stimulation over the longer term, and protect against pro-arrhythmic Ca2+ waves. However, during HF, RyR dispersion was linked to impaired Ca2+ release. Thus, RyR localization and function are intimately linked via channel phosphorylation by both CaMKII and PKA which, while finely tuned in healthy cardiomyocytes, underlies impaired cardiac function during pathology.
Data availability
Custom codes used in this study were written in Python, and is available at the public repository https://gitlab.com/louch-group/ryr-tt-correlative-analsyis.
Article and author information
Author details
William Edward Louch
Funding
Norwegian Research Council
- Xin Shen
- William Edward Louch
European Research Council
- Xin Shen
- Terje R Kolstad
- William Edward Louch
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All animal experiments were performed in accordance with the Norwegian Animal Welfare Act and NIH Guidelines, and were approved by the Ethics Committee of the University of Oslo and the Norwegian animal welfare committee (FOTS ID 20208). The majority of the experiments were performed on adult male Wistar rats (250-350 g) purchased from Janvier Labs (Le Genest-Saint-Isle, France). Rats were group housed at 22{degree sign}C on a 12 h:12 h light-dark cycle, with free access to food and water. Cardiomyocytes isolated from transgenic RyR2-S2814D and RyR2-S2814A mice were provided by the laboratory of Xander Wehren (Baylor College of Medicine, Texas, United States) where experiments were performed in accordance with the Guide for the Care and Use of Laboratory Animals (National Academies Press, 2011) and approved by the Baylor College of Medicine Institutional Animal Care and Use Committee. A total of 64 rats and 6 mice were used in this study.
Copyright
© 2022, Shen et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Prolonged β-adrenergic stimulation disperses ryanodine receptor clusters in cardiomyocytes
eLife 11:e77725.
https://doi.org/10.7554/eLife.77725
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