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bioRxiv · 10.1101/2021.05.06.442917

Cardioluminescence in transgenic zebrafish embryos: a calcium imaging tool to study drug effects and pathological modeling

Vicente, M.·Salgado-Almario, J.·Collins, M. M.·Martinez-Sielva, A.·Minoshima, M.·Kikuchi, K.·Domingo, B.·Llopis, J.
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Abstract

The zebrafish embryo has emerged as an excellent model in cardiovascular research. The existing techniques to monitor Ca2+ in the heart based on fluorescent Ca2+ biosensors are limited due to phototoxicity and photobleaching. To overcome these issues, we have used bioluminescence. We generated a transgenic line expressing GFP-Aequorin in the heart, Tg(cmlc2:GA), and optimized an in vivo aequorin reconstitution protocol to improve the luminescence capacity. This allowed imaging Ca2+ in long duration recordings in embryos of 3 to 5 days post-fertilization. The analogs diacetyl h-coelenterazine and f-coelenterazine enhanced the light output and signal-to-noise ratio from the embryos. With this cardioluminescence model, we monitored the time-averaged Ca2+ levels and beat-to-beat Ca2+ oscillations. Changes in Ca2+ levels were observed by incubation with BayK8644, an L-type Ca2+ channel agonist, the channel blocker nifedipine, and {beta}-adrenergic blocker propranolol. Treatment of zebrafish embryos with terfenadine for 24 hours has been proposed as a model of heart failure. Tg(cmlc2:GA) embryos treated with terfenadine showed a 2:1 atrioventricular block and a decrease in the ventricular Ca2+ levels.

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Vicente, M., Salgado-Almario, J., Collins, M. M., Martinez-Sielva, A., Minoshima, M., Kikuchi, K., Domingo, B., Llopis, J.. 2021-05-07. Cardioluminescence in transgenic zebrafish embryos: a calcium imaging tool to study drug effects and pathological modeling. https://doi.org/10.1101/2021.05.06.442917

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