Expansion of genetically corrected neutrophils in chronic granulomatous disease mice by cotransferring a therapeutic gene and a selective amplifier gene.
Hematopoietic stem cell gene therapy has not provided clinical success in disorders such as chronic granulomatous disease (CGD), where genetically corrected cells do not show a selective advantage in vivo. To facilitate selective expansion of transduced cells, we have developed a fusion receptor system that confers drug-induced proliferation. Here, a 'selective amplifier gene (SAG)' encodes a chimeric receptor (GcRER) that generates a mitotic signal in response to estrogen. We evaluated the in vivo efficacy of SAG-mediated cell expansion in a mouse disease model of X-linked CGD (X-CGD) that is deficient in the NADPH oxidase gp91phox subunit. Bone marrow cells from X-CGD mice were transduced with a bicistronic retrovirus encoding GcRER and gp91phox, and transplanted to lethally irradiated X-CGD recipients. Estrogen was administered to a cohort of the transplants, and neutrophil superoxide production was monitored. A significant increase in oxidase-positive cells was observed in the estrogen-treated mice, and repeated estrogen administration maintained the elevation of transduced cells for 20 weeks. In addition, oxidase-positive neutrophils were increased in the X-CGD transplants given the first estrogen even at 9 months post-transplantation. These results showed that the SAG system would enhance the therapeutic effects by boosting genetically modified, functionally corrected cells in vivo.
Hara
T
T
Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical School, Tochigi, Japan.
Kume
A
A
Hanazono
Y
Y
Mizukami
H
H
Okada
T
T
Tsurumi
H
H
Moriwaki
H
H
Ueda
Y
Y
Hasegawa
M
M
Ozawa
K
K
D000818:Animals; D045303:Cytochromes b / Q000235:genetics; D004967:Estrogens / Q000627:therapeutic use; D005784:Gene Amplification; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006105:Granulomatous Disease, Chronic / Q000473:pathology / Q000628:therapy*; D007958:Leukocyte Count; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008938:Mitosis / Q000235:genetics; D009504:Neutrophils / Q000378:metabolism* / Q000473:pathology; D011960:Receptors, Estrogen / Q000235:genetics; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012190:Retroviridae / Q000235:genetics; D013481:Superoxides / Q000032:analysis / Q000378:metabolism; D014161:Transduction, Genetic / Q000379:methods*
D004967:Estrogens; D011960:Receptors, Estrogen; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D011993:Recombinant Fusion Proteins; D013481:Superoxides; D045303:Cytochromes b