Muscle-specific promoters may be necessary for adeno-associated virus-mediated gene transfer in the treatment of muscular dystrophies.
Recombinant adeno-associated virus (rAAV) vectors allow efficient gene transfer and expression in the muscle; therefore, rAAVs represent a potential gene therapy vector for muscular dystrophies. For further investigations, we used a mouse muscular dystrophy model (gsg(-/-) mice) gamma-sarcoglycan, a subunit of the dystrophin-glycoprotein complex, is missing. gsg(-/-) mice develop progressive dystrophy representative of a severe human phenotype disease. We previously showed high levels and stable expression of gamma-sarcoglycan in myofibers after direct muscle injection into gsg(-/-) mice of a recombinant AAV vector (AAV.dMCK.gSG) carrying the gamma-sarcoglycan cDNA driven by a muscle-specific promoter (truncated version of muscle creatine kinase). Here, we show that when gamma-sarcoglycan expression is driven by the ubiquitous cytomegalovirus (CMV) promoter (AAV.CMV.gSG), lower levels of transgene expression are observed and are associated with a humoral response to gamma-sarcoglycan. When using an rAAV vector, expressing the highly immunogenic product gamma-galactosidase under the CMV promoter (AAV.CMV.LacZ), we measured a strong cellular and humoral immune response to the transgene after intramuscular injection into gsg(-/-) mice. This study suggests that restriction of transgene expression to the muscle is an important criterion for the treatment of muscular dystrophies and will aid in the design of protocols for gene therapy.
Cordier
L
L
Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104; Cell Genesys, Foster City, CA 94404.
Gao
G P
GP
Hack
A A
AA
McNally
E M
EM
Wilson
J M
JM
Chirmule
N
N
Sweeney
H L
HL
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D015153:Blotting, Western; D003402:Creatine Kinase / Q000235:genetics; D003598:Cytoskeletal Proteins / Q000096:biosynthesis*; D003713:Dendritic Cells / Q000276:immunology; D000229:Dependovirus / Q000235:genetics*; D016189:Dystrophin / Q000096:biosynthesis; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006801:Humans; D007124:Immunoenzyme Techniques; D008264:Macrophages / Q000502:physiology; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D018482:Muscle, Skeletal / Q000378:metabolism*; D009136:Muscular Dystrophies / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000628:therapy*; D011401:Promoter Regions, Genetic; D049031:Sarcoglycans; D013602:T-Lymphocytes, Cytotoxic; D014161:Transduction, Genetic; D001616:beta-Galactosidase / Q000378:metabolism
D003598:Cytoskeletal Proteins; D016189:Dystrophin; D008562:Membrane Glycoproteins; D049031:Sarcoglycans; D003402:Creatine Kinase; D001616:beta-Galactosidase