N. Chossat et al., Adenoviral SERCA1a gene transfer to adult rat ventricular myocytes inducesphysiological changes in calcium handling, CARDIO RES, 49(2), 2001, pp. 288-297
Citations number
25
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Objective: We examined the functional consequences of expressing adult rabb
it fast skeletal sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA1a) in isola
ted adult rat ventricular myocytes. Methods: Myocytes were infected with a
recombinant adenovirus harboring SERCA1a. Then 2 days after myocyte infecti
on, protein expression was estimated using Western blot and SDS-PAGE analys
is. We also measured the ATP-dependent oxalate-facilitated Ca2+ uptake of m
yocyte homogenates and monitored Ca2+ transient in myocytes loaded with the
Ca2+ dye, indo-1. Results: SERCA1a gene expression resulted in a 36% incre
ase in the total SERCA protein level in infected myocytes compared to contr
ols (P<0.01), white SERCA2 and phospholamban levels did not change. This in
crease was associated with a 42% rise in SR Ca2+ uptake (P<0.01), while tau
(the time constant of Ca2+ transient decay), and the time to peak fell by
32% (P<0.01) and 38% (P<0.001), respectively. Increasing the frequency of s
timulation from 0.2 to 2 Hz decreased tau in both cell types (P<0.01). Howe
ver, the decrease was much smaller in infected (P<0.01) than in uninfected
cells (P<0.001). Isoproterenol (1 <mu>M) further decreased tau in infected
myocytes by 23% (P<0.05). In these cells, the diastolic [Ca2+](i) decreased
by 50% (P<0.05) while the systolic [Ca2+](i) increased by 19% (P<0.05). No
difference was found in the speed of SR Ca2+ reloading after caffeine wash
out between the two cell types. Conclusion: Adenovirus-mediated SERCA1a gen
e transfer to adult rat ventricular myocytes enhances SR Ca2+ handling to a
degree similar to that observed following physiological stimulation. (C) 2
001 Elsevier Science B.V. All rights reserved.