473 Application of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) for modeling of Ankyrin-2 p.R990Q variant-induced ventricular arrhythmia and personalized medicine

Abstract

OBJECTIVES/GOALS: The cytoskeletal protein α²II spectrin interacts with actin and ankyrin-2 in cardiomyocytes which is essential to orchestrate ion channels and membrane proteins in the cardiac dyad. Our goal is to understand molecular mechanism causing severe ventricular arrhythmias due to spectrin dysfunction and explore novel therapies to treat such conditions. METHODS/STUDY POPULATION: We previously published a case of a 36-year-old woman with an ankyrin-2 p.R990Q (ANK2) variant, presented with severe ventricular arrhythmias and sudden cardiac arrest, caused by a novel mutation in the ankyrin-B gene (c.2969G>A) that disrupts the interaction of ankyrin-B/βII spectrin. To model the condition, we will use human induced pluripotent stem cell (DF 19-9-7T, WiCell)-derived ventricular cardiomyocytes (iPSC-CMs) having ANK2 variant, engineered using CRISPR/Cas9 method (Synthego Corp.). We will validate the differentiation of iPSCs into ventricular lineage and characterize the ANK2 ventricular phenotype. Next, we will express light-gated cation channel Channelrhodopsin (ChR2) in the ANK2 iPSC-CMs and investigate the potential role of optogenetics in treating such severe arrhythmias. RESULTS/ANTICIPATED RESULTS: Immunostaining shows 87.339% of iPSC-CMs, treated with All-trans retinoic acid (RA) (1 uM) on days 7 and 12 [RA 7,12], and 23.84% of those, treated on days 3 and 5 [RA 3,5], expressed MLC-2V (p<0.001). Calcium reuptake (τ) is 0.5914 s in RA 7, 12 while 0.2247s in RA 3, 5 (p<0.001). APD90 and APD50 of RA 7, 12 are 2- and 5-fold higher than RA 3, 5, showing distinct ventricular and atrial phenotypes. Protein expression of βII-spectrin and ankyrin-2 and their co-localizations were reduced in the ANK2 phenotype compared to the healthy phenotype. We found prolongation of Ca2+ waves and τ with blue light on iPSC-CMs, expressing ChR2. We anticipate that such prolongation of calcium transients would prevent aberrant calcium spikes, rescue Ca2+/calpain-induced βII-spectrin loss and provide electrical stability. DISCUSSION/SIGNIFICANCE: Animal models cannot accurately recapitulate human cardiac electrophysiology. The proposed human iPSC-CM-based ANK2 model would provide better mechanistic insights of severe ventricular arrhythmias. Also, the proposed optogenetic cardioversion has the potential to provide safe, targeted and painless cardioversion to manage arrhythmias.