Development of a novel transgenic zebrafish model to determine the pathogenicity of genetic variants for cardiac arrhythmia.

Inherited Cardiac Arrhythmia (ICA), such as long QT syndrome (LQTS) and Brugada syndrome (BrS), refers to a group of hereditary disorders in which patients present with irregular heart rhythm, caused by altered cardiac electrical dynamics. These episodes can remain asymptomatic, but also lead to sudden syncope and sudden death of the individual. Up to date, over 50 different genes have been identified that can cause ICA. Thanks to the advent of next generation sequencing it is possible to test all these genes simultaneously in multiple ICA patients in a single experiment, allowing the identification of pathogenic genetic alterations. However, we are also confronted with a high number of genetic alterations for which it is unsure whether they are causally involved in the disease or not, so-called variants of unknown significance. Therefore, there is a high need for a physiologically relevant functional tool to test the pathogenicity of these variants. By combining two state-of-the-art techniques, genetically encoded voltage indicators (GEVI) and selective plane illumination microscopy (SPIM), I will develop such a novel tool to study the cardiac conduction system and characterize its anatomical connectivity in zebrafish at an unprecedented resolution. By converting electrical dynamics of the zebrafish heart into fluorescent signals, this tool will enable me to optically map action potentials in the complete heart at single cell level. This will allow me to determine cardiac conduction speed and observe conduction delays, making it a novel and ideal tool to investigate the electro- and pathophysiological mechanisms underlying two arrhythmia syndromes, LQTS and especially BrS. Finally, using this functional assay, I will be able to evaluate the pathogenicity of genetic variants with an unknown clinical significance.

Keywords:ZEBRAFISH, OPTOGENETICS, SUDDEN DEATH

Disciplines:Genetics, Systems biology, Cardiac and vascular medicine, Molecular and cell biology