RT Journal Article
SR Electronic
T1 Automated high-throughput heart rate measurement in medaka and zebrafish embryos under physiological conditions
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 548594
DO 10.1101/548594
A1 Jakob Gierten
A1 Christian Pylatiuk
A1 Omar Hammouda
A1 Christian Schock
A1 Johannes Stegmaier
A1 Joachim Wittbrodt
A1 Jochen Gehrig
A1 Felix Loosli
YR 2019
UL http://biorxiv.org/content/early/2019/02/13/548594.abstract
AB Rationale Accurate and efficient quantification of heartbeats in small fish models is an important readout to study cardiovascular biology, disease states and pharmacology at large scale. However, dependence on anesthesia, laborious sample orientation or requirement for fluorescent reporters have hampered the establishment of high-throughput heartbeat analysis.Objective To overcome these limitations, we aimed to develop a high-throughput assay with automated heart rate scoring in medaka (Oryzias latipes) and zebrafish (Danio rerio) embryos under physiological conditions designed for genetic screens and drug discovery and validation.Methods and Results We established an efficient screening assay employing automated label-free heart rate determination of randomly oriented, non-anesthetized specimen in microtiter plates. Automatically acquired bright-field data feeds into an easy-to-use HeartBeat software, a MATLAB algorithm with graphical user interface developed for automated quantification of heart rate and rhythm. Sensitivity of the assay and algorithm was demonstrated by profiling heart rates during entire embryonic development. Our analysis pipeline revealed acute temperature changes triggering rapid adaption of heart rates, which has implications for standardization of experimental layout. The approach is scalable and allows scoring of multiple embryos per well resulting in a throughput of >500 embryos per 96-well plate. In a proof of principle screen for compound testing, our assay captured concentration-dependent effects of nifedipine and terfenadine over time.Conclusion A novel workflow and HeartBeat software provide efficient means for reliable and direct quantification of heart rate and rhythm of small fish in a physiological environment. Importantly, confounding factors such as anesthetics or laborious mounting are eliminated. We provide detailed profiles of embryonic heart rate dynamics in medaka and zebrafish as reference for future assay development. Ease of sample handling, automated imaging, physiological conditions and software-assisted analysis now facilitate various large-scale applications ranging from phenotypic screening, interrogation of gene functions to cardiovascular drug development pipelines.Non-standard abbreviations and acronymsdpfdays post fertilizationhpfhours post fertilizationmyl7regulatory myosin light chain 7Tol2Transposon Oryzias latipes 2