Viral delivered gene therapy to treat catecholaminergic polymorphic ventricular tachycardia (CPVT2) in mouse models

Efrat Kurtzwald-Josefson, Dor Yadin, Shiraz Harun-Khun, Maayan Waldman, Dan Aravot, Asher Shainberg, Michael Eldar, Edith Hochhauser, Michael Arad

Research output: Contribution to journalArticlepeer-review

Abstract

Background The recessive form of catecholaminergic polymorphic ventricular tachycardia 2 (CPVT2) is caused by mutations in cardiac calsequestrin (CASQ2), leading to protein deficiency. Objectives The aims of this study were to develop a viral-delivered gene therapy for CPVT2 and to determine the relationship between CASQ2 expression and antiarrhythmic efficacy in a murine model. Methods We used a murine model of CPVT2 caused by the D307H human mutation (CASQ2D307H) or CASQ2 knockout (CASQ2Δ/Δ). Adeno-associated virus (AAV) particles containing the CASQ2 gene (AAVCASQ2) were injected into the heart or intraperitoneally to 12-week-old mice. A telemetry device was implanted, and mice underwent provocation testing 7–8 weeks after gene therapy. Results CASQ2Δ/Δ mice injected intracardiacally with AAVCASQ2 expressed 40% ± 25% of the normal CASQ2 protein level, which was increased compared to untreated CASQ2Δ/Δ mice (n = 10; P <.05). Intraperitoneal therapy led to a significantly elevated expression of the CASQ2 protein, which was comparable in CASQ2D307H (n = 12) and CASQ2Δ/Δ (n = 4) mice. All control mice with CPVT2 had nonsustained ventricular tachycardia (VT) and 8 of 13 had sustained VT on provocation. Expressing ≥33% of the normal CASQ2 level was needed to protect from nonsustained VT as well as stress-induced premature ventricular contractions. Lower levels of expression prevented sustained VT in AAVCASQ2-treated mice (0 of 26; P <.001 vs controls). Conclusion AAVCASQ2 displays a long-lasting capacity to attenuate and potentially cure CPVT2. Systemic delivery is feasible and convenient, reproducibly providing adequate levels of transgene expression. Antiarrhythmic efficacy depends on the CASQ2 level: ≥33% of the normal CASQ2 level is needed to prevent arrhythmia. However, even lower levels of protein protect from sustained VT, thereby potentially reducing the risk of sudden death.

Original languageEnglish
Pages (from-to)1053-1060
Number of pages8
JournalHeart Rhythm
Volume14
Issue number7
DOIs
StatePublished - Jul 2017

Keywords

  • Adeno-associated virus
  • CPVT
  • Calsequestrin
  • Gene therapy
  • Ventricular arrhythmia

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