Overexpression of connexin 43 in skeletal myoblasts: Relevance to cell transplantation to the heart.
OBJECTIVE
Skeletal myoblast transplantation is a promising strategy for treating end-stage heart failure. One potential problem in the development of functional, synchronously contracting grafts is the degree of intercellular communication between grafted myoblasts and host cardiomyocytes. Thus it is expected that enhancement of intercellular gap junction formation would result in improved efficiency of skeletal myoblast transplantation. In this study we investigated whether myoblasts overexpressing connexin 43, a major cardiac gap junction protein, would enhance this intercellular communication.


RESULTS
L6 rat skeletal myoblast cell lines overexpressing connexin 43 were generated by means of gene transfection and clonal selection. Connexin 43 overexpression of these myoblasts, which continued both in undifferentiated and differentiated states (up to 17-fold greater protein level in comparison with control-transfected myoblasts, as measured with Western blotting), was observed on cell surfaces where gap junctions should exist. Both dye microinjection and scrape loading with fluorescent dyes showed enhancement in intercellular dye transfer between connexin 43-transfected myoblasts compared with that found in control-transfected cells. Morphologically, these myoblasts fused and differentiated into multinucleated myotubes more rapidly, demonstrating a higher level of cellular creatine kinase activity as a marker of myogenic differentiation throughout the culture period compared with that of control-transfected myoblasts.


CONCLUSIONS
We have generated connexin 43-overexpressing skeletal myoblast cell lines that resulted in improved formation of functional intercellular gap junctions, which could be relevant to synchronous contraction of grafted myoblasts in the heart. In addition, these cells demonstrated more rapid differentiation, which would also be advantageous in a graft for transplantation to the heart.
Suzuki
K
K
Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College School of Medicine at the Heart Science Centre, Harefield Hospital, Middlesex, United Kingdom.
Brand
N J
NJ
Allen
S
S
Khan
M A
MA
Farrell
A O
AO
Murtuza
B
B
Oakley
R E
RE
Yacoub
M H
MH
D000818:Animals; D006348:Cardiac Surgical Procedures; D002450:Cell Communication; D002455:Cell Division; D017690:Cell Transplantation; D018031:Connexin 43 / Q000096:biosynthesis*; D005786:Gene Expression Regulation; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism*; D051381:Rats
D018031:Connexin 43