Prolonged High-Level Detection of Retrovirally Marked Hematopoietic Cells in Nonhuman Primates after Transduction of CD34+ Progenitors Using Clinically Feasible Methods.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1137-1137
Author(s):  
Tong Wu ◽  
Hyeoung Joon Kim ◽  
Stephanie E. Sellers ◽  
Kristin E. Meade ◽  
Brian A. Agricola ◽  
...  

Abstract Low-level retroviral transduction and engraftment of hematopoietic long-term repopulating cells in large animals and humans remain primary obstacles to the successful application of hematopoietic stem cell(HSC) gene transfer in humans. Recent studies have reported improved efficiency by including stromal cells(STR), or the fibronectin fragment CH-296(FN), and various cytokines such as flt3 ligand(FLT) during ex vivo culture and transduction in nonhuman primates. In this work, we extend our studies using the rhesus competitive repopulation model to further explore optimal and transduction in the presence of either preformed autologous STR or immobilized FN. Long-term clinically relevant gene marking levels in multiple hematopoietic lineages from both conditions were demonstrated in vivo by semiquantitative PCR, colony PCR, and genomic Southern blotting, suggesting that FN could replace STR in ex vivo transduction protocols. Second, we compared transduction on FN in the presence of IL-3, IL-6, stem cell factor(SCF), and FLT(our best cytokine combination in prior studies)with a combination of megakaryocyte growth and development factor(MGDF), SCF, and FLT. Gene marking levels were equivalent in these animals, with no significant effect on retroviral gene transfer efficiency assessed in vivo by the replacement of IL-3 and IL-6 with MGDF. Our results indicate that SCF/G-CSF-mobilized PB CD34+ cells are transduced with equivalent efficiency in the presence of either STR or FN, with stable long-term marking of multiple lineages at levels of 10–15% and transient marking as high as 54%. These results represent an advance in the field of HSC gene transfer using methods easily applied in the clinical setting.

Blood ◽  
1999 ◽  
Vol 94 (7) ◽  
pp. 2271-2286 ◽  
Author(s):  
M. Rosenzweig ◽  
T.J. MacVittie ◽  
D. Harper ◽  
D. Hempel ◽  
R.L. Glickman ◽  
...  

Optimization of mobilization, harvest, and transduction of hematopoietic stem cells is critical to successful stem cell gene therapy. We evaluated the utility of a novel protocol involving Flt3-ligand (Flt3-L) and granulocyte colony-stimulating factor (G-CSF) mobilization of peripheral blood stem cells and retrovirus transduction using hematopoietic growth factors to introduce a reporter gene, murine CD24 (mCD24), into hematopoietic stem cells in nonhuman primates. Rhesus macaques were treated with Flt3-L (200 μg/kg) and G-CSF (20 μg/kg) for 7 days and autologous CD34+ peripheral blood stem cells harvested by leukapheresis. CD34+ cells were transduced with an MFGS-based retrovirus vector encoding mCD24 using 4 daily transductions with centrifugations in the presence of Flt3-L (100 ng/mL), human stem cell factor (50 ng/mL), and PIXY321 (50 ng/mL) in serum-free medium. An important and novel feature of this study is that enhanced in vivo engraftment of transduced stem cells was achieved by conditioning the animals with a low-morbidity regimen of sublethal irradiation (320 to 400 cGy) on the day of transplantation. Engraftment was monitored sequentially in the bone marrow and blood using both multiparameter flow cytometry and semi-quantitative DNA polymerase chain reaction (PCR). Our data show successful and persistent engraftment of transduced primitive progenitors capable of giving rise to marked cells of multiple hematopoietic lineages, including granulocytes, monocytes, and B and T lymphocytes. At 4 to 6 weeks posttransplantation, 47% ± 32% (n = 4) of granulocytes expressed mCD24 antigen at the cell surface. Peak in vivo levels of genetically modified peripheral blood lymphocytes approached 35% ± 22% (n = 4) as assessed both by flow cytometry and PCR 6 to 10 weeks posttransplantation. In addition, naı̈ve (CD45RA+and CD62L+) CD4+ and CD8+cells were the predominant phenotype of the marked CD3+ T cells detected at early time points. A high level of marking persisted at between 10% and 15% of peripheral blood leukocytes for 4 months and at lower levels past 6 months in some animals. A cytotoxic T-lymphocyte response against mCD24 was detected in only 1 animal. This degree of persistent long-lived, high-level gene marking of multiple hematopoietic lineages, including naı̈ve T cells, using a nonablative marrow conditioning regimen represents an important step toward the ultimate goal of high-level permanent transduced gene expression in stem cells.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2113-2113
Author(s):  
Peter Kurre ◽  
Ponni Anandakumar ◽  
Vladimir A. Lesnikov ◽  
Hans-Peter Kiem

Abstract Most gene transfer models using Moloney murine leukemia virus (MLV) - derived vectors to target hematopoietic repopulating cells require progenitor cell enrichment and extended ex vivo culture for efficient long-term marking. Both may result in qualitative, and/or quantitative, loss of stem cells thereby limiting gene transfer rates in vivo. This can be a critical obstacle in candidate applications with exhausted autologous stem cell pools, such as Fanconi Anemia. Among the advantages of HIV-derived lentivirus vectors is their ability to transduce non dividing cells, permitting shortened ex vivo culture durations while maintaining gene transfer to long-term repopulating cells. We have previously reported long-term gene transfer rates of 12–40% after VSV-G/ lentivirus vector transduction of murine stem cells by targeting unseparated marrow cells after reduced prestimulation and a single 12 hour vector exposure (Kurre et al., Mol. Ther. 2004 Jun;9(6):914–22). We herein report studies showing maintenance of gene transfer efficiency in this model at drastically reduced ex vivo vector exposure times. In initial in vitro experiments we studied cytokine support, vector particle density, and minimum exposure duration requirements for efficient gene transfer to unseparated marrow cells. We determined that fibronectin fragment support was critical in maintaining minimum gene transfer efficiencies, even during brief 1, or 3-hour exposures. In an effort to extend these in vitro findings targeting a mixed leukocyte population and explore the feasibility in vivo, we next performed repopulation experiments in myeloablated murine recipients. Unseparated marrow cells harvested from donor animals were depleted of red blood cells, washed and immediately transduced on fibronectin fragment in the presence of murine stem cell factor. Following a 1 hour exposure to lentivector (VSV-G/RRLsin-cPPThPGK-EGFPwpre), cells were washed repeatedly, resuspended and injected into myeloablated recipients (n=10). Animals showed ready hematopoietic reconstitution and demonstrated average GFP marking of 31% (range: 17–41.2%) in peripheral blood 20 weeks after transplantation. Gene marking in secondary recipients 9 weeks after reconstitution (n=15, 3 recipient animals per donor) persisted at 29% on average (range 14.9–66%). Results also demonstrate transduction of granulocytes, B- and T-lymphocytes, as well as stable long-term GFP expression in primary and secondary animals. Copy number determination by real-time PCR in marrow cells from primary recipients shows an average of 4 proviral copies (range 2.1–8.1) per GFP-expressing cell. Our studies confirm that HIV-derived lentivirus vectors are ideally suited for the transduction of murine long-term repopulating cells. We hypothesize that ultra-short transduction actively preserves stem cell content in the inoculum. Moreover, this protocol represents an ideal platform for subsequent in vivo selection to achieve complete phenotype correction and high-level therapeutic chimerism required for some applications. We anticipate that our strategy may prove particularly useful in situations where the target stem cell quantity is greatly limited and cells are of poor ex vivo viability.


Blood ◽  
2009 ◽  
Vol 114 (17) ◽  
pp. 3557-3566 ◽  
Author(s):  
Haiming Xu ◽  
Satyam Eleswarapu ◽  
Hartmut Geiger ◽  
Kathleen Szczur ◽  
Deidre Daria ◽  
...  

Abstract Hematopoietic stem cell (HSC) engraftment is a multistep process involving HSC homing to bone marrow, self-renewal, proliferation, and differentiation to mature blood cells. Here, we show that loss of p190-B RhoGTPase activating protein, a negative regulator of Rho GTPases, results in enhanced long-term engraftment during serial transplantation. This effect is associated with maintenance of functional HSC-enriched cells. Furthermore, loss of p190-B led to marked improvement of HSC in vivo repopulation capacity during ex vivo culture without altering proliferation and multilineage differentiation of HSC and progeny. Transcriptional analysis revealed that p190-B deficiency represses the up-regulation of p16Ink4a in HSCs in primary and secondary transplantation recipients, providing a possible mechanism of p190-B–mediated HSC functions. Our study defines p190-B as a critical transducer element of HSC self-renewal activity and long-term engraftment, thus suggesting that p190-B is a target for HSC-based therapies requiring maintenance of engraftment phenotype.


Author(s):  
Fatima Aerts-Kaya

: In contrast to their almost unlimited potential for expansion in vivo and despite years of dedicated research and optimization of expansion protocols, the expansion of Hematopoietic Stem Cells (HSCs) in vitro remains remarkably limited. Increased understanding of the mechanisms that are involved in maintenance, expansion and differentiation of HSCs will enable the development of better protocols for expansion of HSCs. This will allow procurement of HSCs with long-term engraftment potential and a better understanding of the effects of the external influences in and on the hematopoietic niche that may affect HSC function. During collection and culture of HSCs, the cells are exposed to suboptimal conditions that may induce different levels of stress and ultimately affect their self-renewal, differentiation and long-term engraftment potential. Some of these stress factors include normoxia, oxidative stress, extra-physiologic oxygen shock/stress (EPHOSS), endoplasmic reticulum (ER) stress, replicative stress, and stress related to DNA damage. Coping with these stress factors may help reduce the negative effects of cell culture on HSC potential, provide a better understanding of the true impact of certain treatments in the absence of confounding stress factors. This may facilitate the development of better ex vivo expansion protocols of HSCs with long-term engraftment potential without induction of stem cell exhaustion by cellular senescence or loss of cell viability. This review summarizes some of available strategies that may be used to protect HSCs from culture-induced stress conditions.


1996 ◽  
Vol 184 (6) ◽  
pp. 2261-2270 ◽  
Author(s):  
Kristen M. Hege ◽  
Keegan S. Cooke ◽  
Mitchell H. Finer ◽  
Krisztina M. Zsebo ◽  
Margo R. Roberts

Gene modification of hematopoietic stem cells (HSC) with antigen-specific, chimeric, or “universal” immune receptors (URs) is a novel but untested form of targeted immunotherapy. A human immunodeficiency virus (HIV) envelope–specific UR consisting of the extracellular domain of human CD4 linked to the ζ chain of the T cell receptor (CD4ζ) was introduced ex vivo into murine HSC by retroviral transduction. After transplantation into immunodeficient SCID mice, sustained high level expression of CD4ζ was observed in circulating myeloid and natural killer cells. CD4ζ-transplanted mice were protected from challenge with a lethal dose of a disseminated human leukemia expressing HIV envelope. These results demonstrate the ability of chimeric receptors bearing ζ-signaling domains to activate non–T cell effector populations in vivo and thereby mediate systemic immunity.


Blood ◽  
1999 ◽  
Vol 94 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Laura S. Haneline ◽  
Troy A. Gobbett ◽  
Rema Ramani ◽  
Madeleine Carreau ◽  
Manuel Buchwald ◽  
...  

Fanconi anemia (FA) is a complex genetic disorder characterized by progressive bone marrow (BM) aplasia, chromosomal instability, and acquisition of malignancies, particularly myeloid leukemia. We used a murine model containing a disruption of the murine homologue ofFANCC (FancC) to evaluate short- and long-term multilineage repopulating ability of FancC −/− cells in vivo. Competitive repopulation assays were conducted where “test”FancC −/− or FancC +/+ BM cells (expressing CD45.2) were cotransplanted with congenic competitor cells (expressing CD45.1) into irradiated mice. In two independent experiments, we determined that FancC −/− BM cells have a profound decrease in short-term, as well as long-term, multilineage repopulating ability. To determine quantitatively the relative production of progeny cells by each test cell population, we calculated test cell contribution to chimerism as compared with 1 × 105 competitor cells. We determined that FancC −/− cells have a 7-fold to 12-fold decrease in repopulating ability compared with FancC +/+cells. These data indicate that loss of FancC function results in reduced in vivo repopulating ability of pluripotential hematopoietic stem cells, which may play a role in the development of the BM failure in FA patients. This model system provides a powerful tool for evaluation of experimental therapeutics on hematopoietic stem cell function.


2020 ◽  
Author(s):  
Xiao Fang ◽  
Xiong Fang ◽  
Yujia Mao ◽  
Aaron Ciechanover ◽  
Yan Xu ◽  
...  

Abstract Background Hematopoietic stem cell (HSC) transplantation is an effective treatment strategy for many types of diseases. Peripheral blood (PB) is the most commonly used source of bone marrow (BM)-derived stem cells for current HSC transplantation. However, PB usually contains very few HSCs under normal conditions, as these cells are normally retained within the BM. This retention depends on the interaction between the CXC chemokine receptor 4 (CXCR4) expressed on the HSCs and its natural chemokine ligand, stromal cell-derived factor (SDF)-1α (also named CXCL12) present in the BM stromal microenvironment. In clinical practice, blocking this interaction with a CXCR4 antagonist can induce the rapid mobilization of HSCs from the BM into the PB.Methods C3H/HEJ, DBA/2, CD45.1+, CD45.2+ mice and monkeys were employed in colony-forming unit (CFU) assays, flow cytometry assays, and competitive/non-competitive transplantation assays, to assess the short-term mobilization efficacy of HF51116 and the long-term repopulating (LTR) ability of HSCs. Kinetics of different blood cells and the concentration of HF51116 in PB were also explored by blood routine examinations and pharmacokinetic assays. Results In this paper, we report that a novel small molecule CXCR4 antagonist, HF51116, which was designed and synthesized by our laboratory, can rapidly and potently mobilize HSCs from BM to PB in mice and monkeys. HF51116 not only mobilized HSCs when used alone but also synergized with the mobilizing effects of granulocyte-colony stimulating factor (G-CSF) after co-administration. Following mobilization by HF51116 and G-CSF, the long-term repopulating (LTR) and self-renewing HSCs were sufficiently engrafted in primary and secondary lethally irradiated mice and were able to rescue and support long-term mouse survival. In monkeys, HF51116 exhibited strong HSC mobilization activity and quickly reached the highest in vivo blood drug concentration. Conclusions These results demonstrate that HF51116 is a new promising stem cell mobilizer which specifically targets CXCR4 and merits further preclinical and clinical studies.


Blood ◽  
2000 ◽  
Vol 95 (1) ◽  
pp. 102-110 ◽  
Author(s):  
Craig Dorrell ◽  
Olga I. Gan ◽  
Daniel S. Pereira ◽  
Robert G. Hawley ◽  
John E. Dick

Abstract Current procedures for the genetic manipulation of hematopoietic stem cells are relatively inefficient due, in part, to a poor understanding of the conditions for ex vivo maintenance or expansion of stem cells. We report improvements in the retroviral transduction of human stem cells based on the SCID-repopulating cell (SRC) assay and analysis of Lin− CD34+CD38−cells as a surrogate measure of stem cell function. Based on our earlier study of the conditions required for ex vivo expansion of Lin−CD34+ CD38− cells and SRC, CD34+–enriched lineage–depleted umbilical cord blood cells were cultured for 2 to 6 days on fibronectin fragment in MGIN (MSCV-EGFP-Neo) retroviral supernatant (containing 1.5% fetal bovine serum) and IL-6, SCF, Flt-3 ligand, and G-CSF. Both CD34+CD38− cells (20.8%) and CFC (26.3%) were efficiently marked. When the bone marrow of engrafted NOD/SCID mice was examined, 75% (12/16) contained multilineage (myeloid and B lymphoid) EGFP+ human cells composing as much as 59% of the graft. Half of these mice received a limiting dose of SRC, suggesting that the marked cells were derived from a single transduced SRC. Surprisingly, these culture conditions produced a large expansion (166-fold) of cells with the CD34+CD38− phenotype (n = 20). However, there was no increase in SRC numbers, indicating dissociation between the CD34+CD38− phenotype and SRC function. The underlying mechanism involved apparent downregulation of CD38 expression within a population of cultured CD34+CD38+ cells that no longer contained any SRC function. These results suggest that the relationship between stem cell function and cell surface phenotype may not be reliable for cultured cells. (Blood. 2000;95:102-110)


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