Efficacy of RyR2 inhibitor EL20 in induced pluripotent stem cell‐derived cardiomyocytes from a patient with catecholaminergic polymorphic ventricular tachycardia

Abstract

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac arrhythmia syndrome that often leads to sudden cardiac death. The most common form of CPVT is caused by autosomal‐dominant variants in the cardiac ryanodine receptor type‐2 (RYR2) gene. Mutations in RYR2 promote calcium (Ca2+) leak from the sarcoplasmic reticulum (SR), triggering lethal arrhythmias. Recently, it was demonstrated that tetracaine derivative EL20 specifically inhibits mutant RyR2, normalizes Ca2+ handling and suppresses arrhythmias in a CPVT mouse model. The objective of this study was to determine whether EL20 normalizes SR Ca2+ handling and arrhythmic events in induced pluripotent stem cell‐derived cardiomyocytes (iPSC‐CMs) from a CPVT patient. Blood samples from a child carrying RyR2 variant RyR2 variant Arg‐176‐Glu (R176Q) and a mutation‐negative relative were reprogrammed into iPSCs using a Sendai virus system. iPSC‐CMs were derived using the StemdiffTM kit. Confocal Ca2+ imaging was used to quantify RyR2 activity in the absence and presence of EL20. iPSC‐CMs harbouring the R176Q variant demonstrated spontaneous SR Ca2+ release events, whereas administration of EL20 diminished these abnormal events at low nanomolar concentrations (IC50 = 82 nM). Importantly, treatment with EL20 did not have any adverse effects on systolic Ca2+ handling in control iPSC‐CMs. Our results show for the first time that tetracaine derivative EL20 normalized SR Ca2+ handling and suppresses arrhythmogenic activity in iPSC‐CMs derived from a CPVT patient. Hence, this study confirms that this RyR2‐inhibitor represents a promising therapeutic candidate for treatment of CPVT.

The role of junctophilin proteins in cellular function

“…Finally, future studies may harness the power of new technologies like clustered regularly interspaced short palindromic repeats (CRISPR) genome editing in combination with human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes to decipher mechanisms by which genetic variants in JPH2 cause cardiac disease ( 213 , 214 ). While such studies have been performed on hiPSCs from patients with HCM ( 215 ), there is currently no such lines with cardiomyopathy-linked JPH2 variants.…”

Current management of inherited arrhythmia syndromes associated with the cardiac ryanodine receptor

“…Given the heterogeneity seen within CPVT cohorts, a ‘one size fits all’ therapeutic approach is likely not sufficient. The use of patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) may facilitate a more individualized approach to therapy, and indeed, it has already identified several candidate drugs [29–32]. Perhaps the holy grail of individualized medicine is gene therapy, and significant strides towards realizing this goal have been made with regards to CPVT.…”

Cardiac calcium regulation in human induced pluripotent stem cell cardiomyocytes: Implications for disease modeling and maturation

“…Investigation of other hiPSC-CMs with a variety of pathogenic RYR2 mutations have alson demonstrated an increase in DADs, arrhythmias, SR Ca 2+ leak, and increased RyR2 phosporylation ( Itzhaki et al, 2012 ; Di Pasquale et al, 2013 ; Paavola et al, 2016 ; Preininger et al, 2016 ; Acimovic et al, 2018 ; Mehta et al, 2018 ; Wei et al, 2018 ; Polonen et al, 2020 ; Word et al, 2021 ). Thus, evaluating different RYR2 mutations can lead to mechanistic molecular understanding of disease progression, and provide a platform for precision medicine.…”