Phenotypic and immunologic factors affecting plasmid-mediated in
vivo gene transfer to rat diaphragm.
Petrof, Basil J., Gyula Acsadi, Johanne Bourdon, Neola Matusiewicz,
and Liying Yang.
Respiratory Division, Dept. of Medicine, Royal Victoria Hospital,
and Meakins-Christie Laboratories, McGill University, Montreal,
Quebec, Canada H3A 1A1; Neuromuscular Research Group, Montreal
Neurological Institute, McGill University, Montreal, Quebec, Canada
H3A 2B4
APStracts 3:0029L, 1996.
Little is known about the molecular mechanisms governing adaptive
responses of the diaphragm in the setting of lung disease. By
permitting the study of regulatory elements and the effects of
overexpressing genes of interest, direct in vivo gene transfer to the
diaphragm could be used as a tool to address such questions.
Therefore, we evaluated parameters affecting transfection efficiency
and duration of foreign gene expression in the diaphragm after
plasmid-mediated gene transfer. Reporter gene constructs were
injected into adult rat diaphragm and hindlimb muscles. Transfection
efficiency at 8-10 days post-injection was decreased in large caliber
(>1000 [mu]m2) and type II myosin heavy chain (MHC)-expressing
fibers. There were also strong trends toward augmented transfection
efficiency in type I MHC- and embryonic MHC-expressing fibers. All
diaphragms demonstrated evidence of muscle injury and inflammatory
cell infiltrates at this early time point. By 30 days post-injection,
however, neither inflammation nor reporter gene expression were
detectable in diaphragm or hindlimb muscles of immunocompetent
animals. By contrast, immunosuppressed rats (cyclosporine 15 mg/kg/d)
showed high levels of foreign gene expression at 30 days post
-injection, which remained stable up to 60 days. Therefore,
exploitation of plasmid-mediated in vivo gene transfer as a tool for
studying regulated gene expression in the diaphragm may be
facilitated by the use of immunodeficient animal models.
Received 23 August 1995; accepted in final form 10 January 1996.
APS Manuscript Number L257-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 14 February 96