High-level in vivo gene marking after gene-modified autologous hematopoietic stem cell transplantation without marrow conditioning in nonhuman primates.
The successful engraftment of genetically modified hematopoietic stem cells (HSCs) without toxic conditioning is a desired goal for HSC gene therapy. To this end, we have examined the combination of intrabone marrow transplantation (iBMT) and in vivo expansion by a selective amplifier gene (SAG) in a nonhuman primate model. The SAG is a chimeric gene consisting of the erythropoietin (EPO) receptor gene (as a molecular switch) and c-Mpl gene (as a signal generator). Cynomolgus CD34+ cells were retrovirally transduced with or without SAG and returned into the femur and humerus following irrigation with saline without prior conditioning. After iBMT without SAG, 2-30% of colony-forming cells were gene marked over 1 year. The marking levels in the peripheral blood, however, remained low (<0.1%). These results indicate that transplanted cells can engraft without conditioning after iBMT, but in vivo expansion is limited. On the other hand, after iBMT with SAG, the peripheral marking levels increased more than 20-fold (up to 8-9%) in response to EPO even at 1 year posttransplant. The increase was EPO-dependent, multilineage, polyclonal, and repeatable. Our results suggest that the combination of iBMT and SAG allows efficient in vivo gene transduction without marrow conditioning.
Ueda
Kyoji
K
Center for Molecular Medicine, Jichi Medical School, Tochigi 329-0498, Japan.
Hanazono
Yutaka
Y
Shibata
Hiroaki
H
Ageyama
Naohide
N
Ueda
Yasuji
Y
Ogata
Satoko
S
Tabata
Toshiaki
T
Nagashima
Takeyuki
T
Takatoku
Masaaki
M
Kume
Akihiko
A
Ikehara
Susumu
S
Taniwaki
Masafumi
M
Terao
Keiji
K
Hasegawa
Mamoru
M
Ozawa
Keiya
K
D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D004921:Erythropoietin / Q000494:pharmacology; D015870:Gene Expression; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism; D008252:Macaca fascicularis; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D018121:Receptors, Cytokine / Q000235:genetics* / Q000378:metabolism; D017467:Receptors, Erythropoietin / Q000235:genetics* / Q000378:metabolism; D053628:Receptors, Thrombopoietin; D012190:Retroviridae / Q000235:genetics; D013997:Time Factors; D019172:Transplantation Conditioning
D018952:Antigens, CD34; D011518:Proto-Oncogene Proteins; D018121:Receptors, Cytokine; D017467:Receptors, Erythropoietin; D053628:Receptors, Thrombopoietin; D004921:Erythropoietin; C082218:MPL protein, human