Improvement of mouse beta-thalassemia by electrotransfer of erythropoietin cDNA.
OBJECTIVE
A new intramuscular DNA electrotransfer method for erythropoietin (EPO) expression was evaluated in the natural mouse model of human beta-thalassemia (Hbb-thal1) in terms of its ability to reverse the anemia and improve the thalassemic features of erythrocytes.


METHODS
Intramuscular injection of small amounts of a plasmid encoding mouse EPO, immediately followed by controlled electric pulses, was used.


RESULTS
This procedure induced very high hematocrit levels in beta-thalassemic mice compared to nonelectrotransferred mice. The hematocrit increase was dose dependent, still increased 4 months after injection of plasmid DNA, and associated with a high transgenic EPO blood level in all mice (up to 2500 mU/mL of plasma). EPO gene electrotransfer not only led to a long-lasting and dose-dependent increase in the hematocrit but also to a 100% increase in the lifespan of erythrocytes of thalassemic mice. This was related to a nearly complete reestablishment of alpha/beta globin chain balance, as demonstrated by a marked decrease in unpaired alpha globin chain. Eight months after the first electrotransfer of pCMV-mEPO plasmid, reinjection of the same construct raised the hematocrit to a level close to that observed following the first electrotransfer.


CONCLUSIONS
This is the first description of the use of plasmid DNA to achieve long-term improvement in a mouse model of a human genetic disorder.
Laboratoire Expérimental de Thérapie Génique, Institut Universitaire d'Hématologie, Hôpital Saint-Louis, Paris, France. letg@chu-stlouis.fr
E
E
Payen
M
M
Bettan
P
P
Rouyer-Fessard
Y
Y
Beuzard
D
D
Scherman
D000818:Animals; D003587:Cytomegalovirus / Q000235:genetics; D004274:DNA, Recombinant / Q000008:administration & dosage* / Q000235:genetics; D004195:Disease Models, Animal; D018274:Electroporation; D004921:Erythropoietin / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D005260:Female; D017353:Gene Deletion; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage; D005914:Globins / Q000172:deficiency / Q000235:genetics; D006400:Hematocrit; D007273:Injections, Intramuscular; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000502:physiology; D019076:Transgenes; D017086:beta-Thalassemia / Q000235:genetics / Q000628:therapy*
D004274:DNA, Recombinant; D011993:Recombinant Fusion Proteins; D004921:Erythropoietin; D005914:Globins