iNOS expression in dystrophinopathies can be reduced by somatic gene transfer of dystrophin or utrophin.
BACKGROUND
Nitric oxide (NO) is an inorganic gas produced by a family of NO synthase (NOS) proteins. The presence and the distribution of inducible-NOS (NOS II or iNOS), and NADPH-diaphorase (NADPH-d), a marker for NOS catalytic activity, were determined in muscle sections from control, DMD, and BMD patients.


METHODS
NADPH-d reactivity, iNOS- and nNOS (NOS I)-immunolocalization were studied in muscles from mdx mice before and after somatic gene transfer of dystrophin or utrophin.


RESULTS
In control patients, few fibers (<2%) demonstrated focal accumulation of iNOS in sarcolemma. In DMD patients, a strong iNOS immunoreactivity was observed in some necrotic muscle fibers as well as in some mononuclear cells, and regenerating muscle fibers had diffusely positive iNOS immunoreactivity. In DMD patients, NADPH-d reactivity was increased and mainly localized in regenerating muscle fibers. In mdx mice quadriceps, iNOS expression was mainly observed in regenerating muscle fibers, but not prior to 4 weeks postnatal, and was still present 8 weeks after birth. The expression of dystrophin and the overexpression of utrophin using adenovirus-mediated constructs reduced the number of iNOS-positive fibers in mdx quadriceps muscles. The correction of some pathology in mdx by dystrophin expression or utrophin overexpression was independent of the presence of nNOS.


CONCLUSIONS
These results suggest that iNOS could play a role in the physiopathology of DMD and that the abnormal expression of iNOS could be corrected by gene therapy.
Louboutin
J P
JP
Department of Molecular and Cellular Engineering, University of Pennsylvania, Philadelphia 19104, USA.
Rouger
K
K
Tinsley
J M
JM
Halldorson
J
J
Wilson
J M
JM
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000235:genetics*; D016189:Dystrophin / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D018101:Mice, Inbred mdx; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000473:pathology; D009137:Muscular Dystrophy, Animal / Q000235:genetics / Q000628:therapy*; D020388:Muscular Dystrophy, Duchenne / Q000201:enzymology* / Q000235:genetics / Q000628:therapy; D009252:NADPH Dehydrogenase / Q000032:analysis / Q000276:immunology; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D011401:Promoter Regions, Genetic; D013997:Time Factors; D049411:Utrophin
D003598:Cytoskeletal Proteins; D016189:Dystrophin; D008565:Membrane Proteins; C483600:Utrn protein, mouse; D049411:Utrophin; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D009252:NADPH Dehydrogenase