Abstract Body (Do not enter title and authors here): Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited disorder that is triggered by a catecholaminergic release, causing ventricular tachycardia and even sudden cardiac death (SCD). Current medical management is non-specific and ineffective.
Hypothesis: Leveraging the underlying genetic cause of CPVT will allow us to identify precision therapeutic modalities.
Goal: This project aimed to create a pipeline for utilizing population genomic modeling to drive a precision approach to targeting RyR2, the molecule central to SCD development in CPVT.
Methods: Pathogenic variants were mapped onto the 3D structure of RyR2. A binding pocket candidacy score chart of finding and ranking binding pockets was created. A top binding pocket was chosen based on the score chart and areas of pathogenicity. Utilizing Maestro software, the top binding pocket was screened for small molecules from two different libraries. The top 4 compounds were selected and applied to wild-type and CPVT-associated RYR2-R176Q induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM^WT and iPSC-CM^RQ, respectively) in a dose response manner and intracellular calcium imaging performed using Cal-520. Intracardiac electrophysiology studies were performed on RyR2 mice and number of VT events were observed pre- and post- injection of lead compound.
Results: Population genomic analysis identified the RyR2 pore region with a top binding pocket within the channel and central domain of RyR2. Four compounds predicted to bind and inhibit abnormal RyR2 opening all decreased abnormal calcium leak in iPSC-CM^RQ with minimal effects on iPSC-CM^WT. These molecules had minimal impact “off target” effects on calcium transient generation and calcium cycling in control iPSC-CMs. Early findings reveal the lead compound picked reduced sustained- and NSVT events to 0 in a RyR2 mouse.
Conclusions: We were able to take a genetically informed approach of utilizing pathogenic hotspots as a method of determining binding pockets on RyR2. This specified approach identified 4 compounds which suppressed RyR2-mediated calcium. This pipeline shows promise in developing precision therapies for CPVT.