CIC   05421
CENTRO DE INVESTIGACIONES CARDIOVASCULARES "DR. HORACIO EUGENIO CINGOLANI"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Adeno-Associated Viral gene delivery of calsequestrin 2 protects adult calsequestrin 2-R33Q knock-in mice from developing ventricular tachycardias.
Autor/es:
DENEGRI M; AVELINO CRUZ JE; DE GIUSTI VC; LODOLA F; CURCIO A; BONGIANINO R; LECCIOLI V; BONCOMPAGNI S; PROTASI F; AURICCHIO A; NAPOLITANO C; PRIORI SG
Reunión:
Congreso; American Heart Association. Scientific Seccions 2012; 2012
Resumen:
Background. Catecholaminergic
Polymorphic Ventricular Tachycardia (CPVT) is a highly lethal recessive
arrhythmogenic disease associated with mutations in the calsequestrin 2 (CASQ2)
gene. We previously demonstrated that CASQ2 gene delivery was able to
rescue the arrhythmic phenotype in CASQ2 knock-out (KO) mice 5 months after the
viral infection. The aim of the present study is to investigate the long-term
effects of viral gene delivery in CASQ2-R33Q
missense mutation mouse model.
Methods. Newborn CPVT mice were infected with
adeno-associated viral vector 9 (AAV9) containing the coding sequence of the
wild type CASQ2 co-expressed with green fluorescent protein (GFP) gene.
Furthermore, we evaluated the effect at 7 and 12 months after viral infection
by in vivo ECG analysis, in vitro electrophysiological and
molecular assays.
Results. Telemeter
recording of ECG demonstrated in vivo ventricular tachycardias (VT)
after epinephrine (2 mg/Kg)
administration in only 17% (2 out of 12) of the infected mice, while 87%
(7/8) of the control CASQ2-R33Q homozygous mice presented a clear arrhythmic
phenotype (p<0.005). Additionally, electrophysiological analysis showed that
delayed after depolarization (DADs) and triggered activity (TA) were almost
abolished in GFP-positive cardiomyocytes
(7 months: DADs: 0%, TA 0%, n=18; 12 months: DADs: 8%, TA: 8%, n=12) in comparison with their internal control
(GFP-negative cells, 7 months: DADs:100%, TA: 83%, n=6; 12 months: DADs: 100%,
TA: 71%, n=7; p<0.001). Finally, western blot revealed increased CASQ2
expression in the infected mice and immunofluorescence assay indicated its
correct localization along the z-lines.
Conclusions. In
the present work we show that the viral
expression of CASQ2 is effective for a long period of time and is able to
revert the functional abnormalities of the mutant endogenous protein and to
prevent life-threatening arrhythmias in the knock-in CASQ2-R33Q mice. These data suggest that despite R33Q mice,
at variance with KO mice, express abnormal CASQ2, the gene replacement therapy
is still able to prevent arrhythmogenic mechanisms in vitro and VTs in
vivo thus suggesting that CASQ2-gene transfer may become a novel therapy
for recessive CPVT.