Evaluation of frequency, type, and function of gap junctions between skeletal myoblasts overexpressing connexin43 and cardiomyocytes: relevance to cell transplantation.
Cell transplantation of skeletal myoblasts (SMs) is one possible treatment for repairing cardiac tissue after myocardial injury. However, inappropriate electrical coupling between grafted SMs and host cardiomyocytes may be responsible for the arrhythmias observed in clinical trials of SM transplantation. Whether functional gap junctions occur between the two cell types remains controversial. We have studied the ability of SMs to electrically couple with isolated adult rat cardiomyocytes (CMs) and assessed whether connexin43 (Cx43) overexpression enhanced gap junctional conductance (Gj). C2C12 myoblast lines overexpressing Cx43 were generated by gene transfection and clonal selection. CMs were cocultured with either SMs overexpressing Cx43 (CM-SM(Cx43)) or control SMs (CM-SM(WT)) in vitro. Gj between pairs of SMs and CMs was quantified with dual whole cell patch clamping. Formation of Gj occurred between 22% of CM-SM(WT) pairs (n=73) and 48% of CM-SM(Cx43) pairs (n=71, P<0.001). The Gj of CM-SM(Cx43) pairs (29.7+/-4.3 nS, n=21) was greater than that of CM-SM(WT) pairs (14.8+/-2.0 nS, n=12, P<0.05). The overexpression of Cx43 in SMs increased the formation of electrical communication and the steady-state conductance between SMs and CMs. Enhanced gap junctional conductance may be useful to promote the integration of transplanted SMs into the myocardium.
Stagg
Mark A
MA
Cellular Electrophysiology, Heart Science Centre, National Heart & Lung Institute, Imperial College London, Harefield Hospital, London, UK. m.stagg@imperial.ac.uk
Coppen
Steven R
SR
Suzuki
Ken
K
Varela-Carver
Anabel
A
Lee
Joon
J
Brand
Nigel J
NJ
Fukushima
Satsuki
S
Yacoub
Magdi H
MH
Terracciano
Cesare M N
CM
D000818:Animals; D002450:Cell Communication; D017690:Cell Transplantation; D002478:Cells, Cultured; D018920:Coculture Techniques; D018031:Connexin 43 / Q000378:metabolism*; D004553:Electric Conductivity; D017629:Gap Junctions / Q000502:physiology*; D008297:Male; D051379:Mice; D032448:Myoblasts, Skeletal / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018031:Connexin 43