The Common Marmoset as a Target Preclinical Primate Model for Cytokine and Gene Therapy Studies

Blood ◽  
1999 ◽  
Vol 93 (9) ◽  
pp. 2839-2848 ◽  
Author(s):  
Hitoshi Hibino ◽  
Kenzaburo Tani ◽  
Kenji Ikebuchi ◽  
Ming-Shiuan Wu ◽  
Hajime Sugiyama ◽  
...  

Abstract Nonhuman primate models are useful to evaluate the safety and efficacy of new therapeutic modalities, including gene therapy, before the inititation of clinical trials in humans. With the aim of establishing safe and effective approaches to therapeutic gene transfer, we have been focusing on a small New World monkey, the common marmoset, as a target preclinical model. This animal is relatively inexpensive and easy to breed in limited space. First, we characterized marmoset blood and bone marrow progenitor cells (BMPCs) and showed that human cytokines were effective to maintain and stimulate in culture. We then examined their susceptibility to transduction by retroviral vectors. In a mixed culture system containing both marmoset stromal cells and retroviral producer cells, the transduction efficiency into BMPCs and peripheral blood progenitor cells (PBPCs) was 12% to 24%. A series of marmosets then underwent transplantation with autologous PBPCs transduced with a retroviral vector carrying the multidrug resistance 1 gene (MDR1) and were followed for the persistence of these cells in vivo. Proviral DNA was detectable by polymerase chain reaction (PCR) in peripheral blood granulocytes and lymphocytes in the recipients of gene transduced progenitors up to 400 days posttransplantation. To examine the function of the MDR1 gene in vivo, recipient maromsets were challenged with docetaxel, an MDR effluxed drug, yet the overall level of gene transfer attained in vivo (<1% in peripheral blood granulocytes) was not sufficient to prevent the neutropenia induced by docetaxel treatment. Using this model, we safely and easily performed a series of in vivo studies in our small animal center. Our results show that this small nonhuman primate, the common marmoset, is a useful model for the evaluation of gene transfer methods targeting hematopoietic stem cells.

Blood ◽  
1999 ◽  
Vol 93 (9) ◽  
pp. 2839-2848 ◽  
Author(s):  
Hitoshi Hibino ◽  
Kenzaburo Tani ◽  
Kenji Ikebuchi ◽  
Ming-Shiuan Wu ◽  
Hajime Sugiyama ◽  
...  

Nonhuman primate models are useful to evaluate the safety and efficacy of new therapeutic modalities, including gene therapy, before the inititation of clinical trials in humans. With the aim of establishing safe and effective approaches to therapeutic gene transfer, we have been focusing on a small New World monkey, the common marmoset, as a target preclinical model. This animal is relatively inexpensive and easy to breed in limited space. First, we characterized marmoset blood and bone marrow progenitor cells (BMPCs) and showed that human cytokines were effective to maintain and stimulate in culture. We then examined their susceptibility to transduction by retroviral vectors. In a mixed culture system containing both marmoset stromal cells and retroviral producer cells, the transduction efficiency into BMPCs and peripheral blood progenitor cells (PBPCs) was 12% to 24%. A series of marmosets then underwent transplantation with autologous PBPCs transduced with a retroviral vector carrying the multidrug resistance 1 gene (MDR1) and were followed for the persistence of these cells in vivo. Proviral DNA was detectable by polymerase chain reaction (PCR) in peripheral blood granulocytes and lymphocytes in the recipients of gene transduced progenitors up to 400 days posttransplantation. To examine the function of the MDR1 gene in vivo, recipient maromsets were challenged with docetaxel, an MDR effluxed drug, yet the overall level of gene transfer attained in vivo (<1% in peripheral blood granulocytes) was not sufficient to prevent the neutropenia induced by docetaxel treatment. Using this model, we safely and easily performed a series of in vivo studies in our small animal center. Our results show that this small nonhuman primate, the common marmoset, is a useful model for the evaluation of gene transfer methods targeting hematopoietic stem cells.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3219-3219 ◽  
Author(s):  
Takahiro Ueda ◽  
Sebastian Brenner ◽  
Harry Malech ◽  
Saskia Langemeijer ◽  
Martha Kirby ◽  
...  

Abstract Hematopoietic cells can be highly enriched for repopulating ability based upon efflux of the fluorescent Hoechst 33342 dye by sorting for side population (SP) cells, a phenotype attributed to expression of ABCG2, a member of the ABC transporter superfamily. Intriguingly, murine studies suggest that forced ABCG2 expression prevents hematopoietic differentiation. We sought to determine the effects of forced expression of the ABCG2 gene in hematopoietic stem cells in the nonhuman primate model, a model with proven relevance to human hematopoiesis. We cloned the full-length rhesus ABCG2 (rh-ABCG2) cDNA using a series of primers spanning the entire sequence designed using the published human sequence. Sequence homology was greater than 96%. The rh-ABCG2 gene was then introduced into an MFGS based retroviral vector pseudotyped with the RD114 envelope. Mobilized human peripheral blood CD34-positive cells were transduced with either rh-ABCG2 or human GP91-phox vector with no other payload. All transductions were initiated with 4 x10e5 cells using X-VIVO10/1%HSA/4mM/L L-glutamine supplemented with 100ng/ml_FLT3L, 100ng/ml SCF, 100ng/ml TPO and polybrene (5 ug/ml). RD114 vector was concentrated by ultracentrifugation (83,000g 90minutes 4°C). Gene transfer rates to CFU of greater than 80% were achieved using both vectors with similar gene transfer rate estimated by flow cytometry. ABCG2-transduced human peripheral blood progenitor cells (PBPCs) acquired the SP phenotype, but showed significantly reduced growth compared to control (Day 8: cell counts 7.67+/− 2.54 vs. 17.83+/−6.64 x10e5 for ABCG2 and GP91-phox transduced cells, respectively p=0.0024, n=5). We then examined the engraftment of ABCG2-expressing stem and progenitor cells in the rhesus macaque autologous transplant model. GCSF/SCF mobilized PBPCs were collected from 2 animals and the CD34+ cells were divided and transduced with either vector and infused after lethal irradiation. In vivo marking levels post transplant measured in mononuclear cells and granulocytes from peripheral blood and bone marrow ranged initially from 0.5–4% by Realtime PCR, declined equally over time, and were similar between transduced fractions, with no discrepancy between bone marrow and peripheral blood marking. Furthermore, peripheral blood T cells, B cells and granulocytes expressed ABCG2 at levels predicted by vector copy number long term, and the differential of such cells within the SP gate matched that of the non-SP fraction demonstrating no block to differentiation in the large animal. In vitro studies showed selective protection against mitoxantrone among ABCG2-transduced rhesus PBPCs. Our results confirm the existence of rhesus-ABCG2, support its importance in conferring the SP phenotype, suggest no detrimental effect of its overexpression upon hematopoiesis, and imply a potential role for its overexpression as an in vivo selection strategy for gene therapy applications.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4323-4323
Author(s):  
Yamin Tian ◽  
Yan Dong ◽  
Seiichiro Kobayashi ◽  
Manabu Ozawa ◽  
Kiyoko Izawa ◽  
...  

Abstract Abstract 4323 [Introduction] Patients with Philadelphia chromosome (p190 BCR-ABL fusion gene)-positive acute lymphoblastic leukemia have a poor prognosis despite intensive therapeutic intervention. Although a rodent model of this leukemia was previously established, the genetic and physiological differences between humans and rodents make it difficult to extrapolate the results from these models and apply these findings to human cases. Primates are more genetically related to humans than rodents. In this study, we attempted to develop a leukemia non-human primate model that mimics various human systems. [Methods and results] (1) A third-generation VSV.G pseudotyped lentiviral vector expressing the p190 BCR-ABL fusion gene driven by CMV or PGK promoter was produced (HIV-CMV/PGK-BCR-ABL). Ba/F3 cells, a mIL-3-dependent murine hematopoietic cell line, were transfected with this vector and cultured without mIL-3. These cells rapidly expanded after 12 days, indicating that p190 BCR-ABL gene expression allowed the Ba/F3 cells to grow autonomously. Next, using a biotin-labeled anti-marmoset CD34 monoclonal antibody (clone MA24) which was produced in our laboratory, MACS-sorted bone marrow CD34+ cells were transduced with the lentiviral vector (HIV-CMV/PGK-BCR-ABL) and subjected to the colony formation assay. In the majority of examined colonies, p190 BCR-ABL gene was detected regardless of the promoter. Taken together, the above findings indicate that p190 BCR-ABL gene was efficiently transduced into marmoset hematopoietic stem/progenitor cells. (2) Peripheral blood mononuclear cells (PBMNCs) were collected from individual marmosets after mobilizing the hematopoietic stem/progenitor cells with G-CSF. These cells were stimulated with cytokines (hIL3, hSCF and hTPO), followed by the transduction with the lentiviral vector. These cells were transplanted into marmosets preconditioned with busulfan. In this ex vivo transduction method, p190 BCR-ABL gene expression which was detected in PBMNCs by nested RT-PCR disappeared after day 56 and 100 in two marmosets. (3) Concentrated lentiviral vector was directly injected into the bone marrow cavity of individual marmosets pretreated with 5-fluorouracil and prednisolone. In this in vivo direct injection method, p190 BCR-ABL gene expression was maintained for more than one year and a half. Transduction of p190 BCR-ABL gene into hematopoietic stem/progenitor cells was confirmed by colony forming assay. In this model, one marmoset unexpectedly developed myelofibrosis-like disease. However, none of the marmosets have developed leukemia to date. [Conclusion] We successfully achieved sustained p190 BCR-ABL gene expression in vivo. This novel in vivo approach will help to develop a marmoset leukemia model in the future. Because a multiple-hit model of oncogenesis has been proposed for various human cancers, a genetic mutation in addition to p190 BCR-ABL may be required for the malignant transformation of hematopoietic stem/progenitor cells in the common marmoset. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5530-5530
Author(s):  
Peter A. Horn ◽  
Melanie Wurm ◽  
Ryo Kurita ◽  
Tomoko Yokoo ◽  
Rainer Blasczyk ◽  
...  

Abstract Preclinical animal models are important for evaluating the safety and therapeutic efficacy of new therapeutic modalities such as gene therapy. From the different large animal models, nonhuman primate models have emerged over the last decades as highly desirable experimental systems from both a pathophysiologic and pharmacokinetic viewpoint and the study of nonhuman primates has provided important information on the efficacy and safety of gene therapy systems in vivo prior to human trials. The common marmoset (Callithrix jacchus) has the advantage that it is a small, and thus relatively inexpensive nonhuman primate model. Currently, very little data on the transduction efficiency of foamyviral vectors for gene transfer into marmoset stem cells exists. We therefore performed a direct comparison using identically designed gammaretroviral, lentiviral and foamyviral vector constructs expressing the enhanced green fluorescent protein (EGFP) from the spleen focus forming virus (SFFV) promoter pseudotyped with either the modified human foamy virus (HFV) envelope EM140 or the G-protein of vesicular stomatitis virus (VSV-G) for the transduction of common marmoset embryonic stem cells (CMES) as well as marmoset CD34+ hematopoietic progenitor cells. Virus stocks of these vectors were prepared by polyethyleneimine-mediated transfection of 293T cells and concentrated approximately 10-fold by centrifugation for 4 hours at 10.000 g at 4°C. Three different target cell populations were transduced: common marmoset embryonic stem cells (CMES) or cryopreserved CD34-enriched cells from bone marrow of a common marmoset either after a two-day prestimulation in the presence of IL-6, FLT3L, cSCF and TPO at a concentration of 100 ng/mL each, or after overnight incubation with 100 ng/mL SCF only. Equal numbers of cells were exposed to the four different vector preparations for 14 hours in 12-well dishes coated with CH-296. The read-out was based on fluorescence microscopy of colonies plated in methyl cellulose as well as flow cytometry (FACS). Foamyviral vectors with the foamyviral envelope were the most efficient gene transfer tool for marmoset hematopoietic CD34-positive cells with stable transduction rates of over 80% as assessed by flow cytometry at both 2 or 7 days after the end of transduction and on average 88% transduction efficiency into colony forming cells (CFU-C). Transduction of CFU-C with all other vector preparations was below 60%. In CMES, initial gene transfer rates of over 80% were achieved with the VSV-G pseudotype lentiviral vector, however, expression decreased to 13% after 7 days. In contrast, the foamyviral vector pseudotyped with the foamyviral envelope decreased only from 49% to 24% after 7 days. In conclusion, we achieved stable viral gene transfer and expression in CMES cells as well as highly efficient gene transfer into common marmoset hematopoietic CD34 positive cells using foamyviral vectors. These results suggest that foamyviral vectors may be highly feasible vectors for stem cell gene transfer and thus set the stage for a more detailed analysis of this vector system in transplantation studies in this nonhuman primate model.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4627-4627
Author(s):  
Leopold Sellner ◽  
Marlon Veldwijk ◽  
Marius Stiefelhagen ◽  
Jurgen A. Kleinschmidt ◽  
Stephanie Laufs ◽  
...  

Abstract Due to their pluripotency, human CD34+ hematopoietic stem cells are targets of interest for the treatment of many acquired and inherited disorders of the hematopoietic system using gene therapeutic approaches. Human CD34+ peripheral blood progenitor cells (PBPC) can be readily mobilized into the blood and harvested by leukapheresis, providing an easily accessible source of hematopoietic progenitor cells. Unfortunately, for gene transfer into CD34+ PBPC, most current vector systems either lack sufficient transduction efficiency or an acceptable safety profile. Standard adeno-associated virus-based vectors have an advantageous safety profile, yet lack the required efficiency. Therefore a panel of pseudotyped recombinant adeno-associated viral (rAAV2/1 - rAAV2/6) vectors expressing the eGFP gene was screened on human G-CSF-mobilized CD34+ PBPC to determine their efficacy. In addition, the difference in transgene expression between conventional single-stranded rAAV and self complementary rAAV (scAAV) vectors was determined. For each vector n≥6 was performed and data are shown as mean ± SD. Of all screened conventional rAAV vectors, rAAV2/6 proved to be the most efficient (13.5% ± 9.8% GFP+ and CD34+ PBPC; p&lt;0.001 vs other vectors) on human CD34+ PBPC, followed by rAAV2/2 (2.6% ± 2.0% GFP+ cells) and rAAV2/1 (1.4% ± 1.2% GFP+ cells). For rAAV2/3, rAAV2/4 and rAAV2/5 no relevant gene transfer efficiency (&lt;1% GFP+ cells) was observed. Furthermore, the relevance of the single-to-double-strand conversion block in transduction of human PBPC could be shown using scAAV vectors. scAAV2/6 and scAAV2/2 (both p&lt;0.001) showed significantly higher gene expression (38.4% ± 12.2% and 11.8% ± 5.7% GFP+ cells, respectively) compared to their conventional counterparts in this cell entity. Similar results were observed for scAAV2/1 vectors (2.8% ± 1.9% GFP+ cells), though the difference was not significant. Of note, as previously observed using AAV peptide library-derived rAAV vectors (Sellner et al., 2008, Exp Hematol. 36), also here inter-patient variances in CD34+ PBPC susceptibility were found. For the first time we were able to obtain clinically relevant gene transfer and expression levels (&gt;10%) with expression rates up to 60% in human CD34+ PBPC using an AAV-based vector system, thereby providing an efficient alternative vector system for gene transfer into this clinically important target cell.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3401-3401
Author(s):  
Rebecca L Porter ◽  
Mary A Georger ◽  
Laura M Calvi

Abstract Abstract 3401 Hematopoietic stem and progenitor cells (HSPCs) are responsible for the continual production of all mature blood cells during homeostasis and times of stress. These cells are known to be regulated in part by the bone marrow microenvironment in which they reside. We have previously reported that the microenvironmentally-produced factor Prostaglandin E2 (PGE2) expands HSPCs when administered systemically in naïve mice (Porter, Frisch et. al., Blood, 2009). However, the mechanism mediating this expansion remains unclear. Here, we demonstrate that in vivo PGE2 treatment inhibits apoptosis of HSPCs in naïve mice, as measured by Annexin V staining (p=0.0083, n=6–7 mice/group) and detection of active-Caspase 3 (p=0.01, n=6–7 mice/group). These data suggest that inhibition of apoptosis is at least one mechanism by which PGE2 expands HSPCs. Since PGE2 is a local mediator of injury and is known to play a protective role in other cell types, we hypothesized that it could be an important microenvironmental regulator of HSPCs during times of injury. Thus, these studies explored the role of PGE2 signaling in the bone marrow following myelosuppressive injury using a radiation injury model. Endogenous PGE2 levels in the bone marrow increased 2.9-fold in response to a sub-lethal dose of 6.5 Gy total body irradiation (TBI)(p=0.0004, n=3–11 mice/group). This increase in PGE2 correlated with up-regulation of microenvironmental Cyclooxygenase-2 (Cox-2) mRNA (p=0.0048) and protein levels at 24 and 72 hr post-TBI, respectively. Further augmentation of prostaglandin signaling following 6.5 Gy TBI by administration of exogenous 16,16-dimethyl-PGE2 (dmPGE2) enhanced the survival of functional HSPCs acutely after injury. At 24 hr post-TBI, the bone marrow of dmPGE2-treated animals contained significantly more LSK cells (p=0.0037, n=13 mice/group) and colony forming unit-spleen cells (p=0.037, n=5 mice/group). Competitive transplantation assays at 72 hr post-TBI demonstrated that bone marrow cells from irradiated dmPGE2-treated mice exhibited increased repopulating activity compared with cells from vehicle-treated mice. Taken together, these results indicate that dmPGE2 treatment post-TBI increases survival of functional HSPCs. Since PGE2 can inhibit apoptosis of HSPCs in naïve mice, the effect of dmPGE2 post-TBI on apoptosis was also investigated. HSPCs isolated from mice 24 hr post-TBI demonstrated statistically significant down-regulation of several pro-apoptotic genes and up-regulation of anti-apoptotic genes in dmPGE2-treated animals (3 separate experiments with n=4–8 mice/group in each), suggesting that dmPGE2 initiates an anti-apoptotic program in HSPCs following injury. Notably, there was no significant change in expression of the anti-apoptotic gene Survivin, which has previously been reported to increase in response to ex vivo dmPGE2 treatment of bone marrow cells (Hoggatt et. al., Blood, 2009), suggesting differential effects of dmPGE2 in vivo and/or in an injury setting. Additionally, to ensure that this inhibition of apoptosis was not merely increasing survival of damaged and non-functional HSPCs, the effect of early treatment with dmPGE2 post-TBI on hematopoietic recovery was assayed by monitoring peripheral blood counts. Interestingly, dmPGE2 treatment in the first 72 hr post-TBI significantly accelerated recovery of platelet levels and hematocrit compared with injured vehicle-treated mice (n=12 mice/group). Immunohistochemical analysis of the bone marrow of dmPGE2-treated mice also exhibited a dramatic activation of Cox-2 in the bone marrow microenvironment. This suggests that the beneficial effect of dmPGE2 treatment following injury may occur, both through direct stimulation of hematopoietic cells and also via activation of the HSC niche. In summary, these data indicate that PGE2 is a critical microenvironmental regulator of hematopoietic cells in response to injury. Exploitation of the dmPGE2-induced initiation of an anti-apoptotic program in HSPCs may represent a useful method to increase survival of these cells after sub-lethal radiation injury. Further, amplification of prostaglandin signaling by treatment with PGE2 agonists may also represent a novel approach to meaningfully accelerate recovery of peripheral blood counts in patients with hematopoietic system injury during a vulnerable time when few therapeutic options are currently available. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4168-4168
Author(s):  
Satiro N. De Oliveira ◽  
Francesca Giannoni ◽  
Cinnamon Hardee ◽  
Arineh Sahaghian ◽  
Laurence J N Cooper ◽  
...  

Abstract Abstract 4168 Chimeric Antigen Receptors (CAR) against CD19 have been shown to direct T cells to specifically target B-lineage malignant cells in animal models and clinical trials, with efficient tumor cell lysis. But, there has been insufficient persistence of effector cells, limiting the clinical efficacy. We propose gene transfer to hematopoietic stem/progenitor cells (HSPC) as a novel approach to ensure persistent production of effector cells targeting B-lineage malignant cells, exponentially increasing the number of effectors that may be generated against tumor cells. Experiments were performed using NOD-SCID-IL2 receptor gamma chain null (NSG) mice engrafted with human CD34+ HSPCs transduced with lentiviral vectors carrying first and second generations of CD19-specific CAR. There was efficient and stable transduction with 1–2 copies of CAR/cell as determined by qPCR. Differentiation of modified HSPC in vivo was not impaired by gene transfer, as observed in vitro. Results of in vivo studies showed that CAR-transduced human HSPC successfully differentiated into all lineages, with CAR-expressing T, NK and myeloid cells populating bone marrow, spleen and peripheral blood. The human CD19+ B cell populations normally formed in the xenografted NSG mice were significantly reduced when the transplanted HSPC were transduced with the anti-CD19 CAR, demonstrating in vivo biological activity. Cells harvested from bone marrow and spleen of mice engrafted with modified HSPC lysed CD19-positive cell targets ex vivo. Leukemic challenges of engrafted mice are in progress. Our results provide evidence for the feasibility and efficacy of the modification of HSPC with CAR as a protocol for generation of effector cells for immunotherapy against B-lineage malignancies. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 513-513
Author(s):  
Pekka Jaako ◽  
Shubhranshu Debnath ◽  
Karin Olsson ◽  
Axel Schambach ◽  
Christopher Baum ◽  
...  

Abstract Abstract 513 Diamond-Blackfan anemia (DBA) is a congenital erythroid hypoplasia associated with physical abnormalities and predisposition to cancer. Mutations in genes that encode ribosomal proteins have been identified in approximately 60–70 % of the patients. Among these genes, ribosomal protein S19 (RPS19) is the most common DBA gene (25 % of the cases). Current DBA therapies involve risks for serious side effects and a high proportion of deaths are treatment-related underscoring the need for novel therapies. We have previously demonstrated that enforced expression of RPS19 improves the proliferation, erythroid colony-forming potential and differentiation of patient derived RPS19-deficient hematopoietic progenitor cells in vitro (Hamaguchi, Blood 2002; Hamaguchi, Mol Ther 2003). Furthermore, RPS19 overexpression enhances the engraftment and erythroid differentiation of patient-derived hematopoietic stem and progenitor cells when transplanted into immunocompromised mice (Flygare, Exp Hematol 2008). Collectively these studies suggest the feasibility of gene therapy in the treatment of RPS19-deficient DBA. In the current project we have assessed the therapeutic efficacy of gene therapy using a mouse model for RPS19-deficient DBA (Jaako, Blood 2011; Jaako, Blood 2012). This model contains an Rps19-targeting shRNA (shRNA-D) that is expressed by a doxycycline-responsive promoter located downstream of Collagen A1 gene. Transgenic animals were bred either heterozygous or homozygous for the shRNA-D in order to generate two models with intermediate or severe Rps19 deficiency, respectively. Indeed, following transplantation, the administration of doxycycline to the recipients with homozygous shRNA-D bone marrow results in an acute and lethal bone marrow failure, while the heterozygous shRNA-D recipients develop a mild and chronic phenotype. We employed lentiviral vectors harboring a codon-optimized human RPS19 cDNA driven by the SFFV promoter, followed by IRES and GFP (SFFV-RPS19). A similar vector without the RPS19 cDNA was used as a control (SFFV-GFP). To assess the therapeutic potential of the SFFV-RPS19 vector in vivo, transduced c-Kit enriched bone marrow cells from control and homozygous shRNA-D mice were injected into lethally irradiated wild-type mice. Based on the percentage of GFP-positive cells, transduction efficiencies varied between 40 % and 60 %. Three months after transplantation, recipient mice were administered doxycycline in order to induce Rps19 deficiency. After two weeks of doxycycline administration, the recipients transplanted with SFFV-RPS19 or SFFV-GFP control cells showed no differences in blood cellularity. Remarkably, at the same time-point the recipients with SFFV-GFP homozygous shRNA-D bone marrow showed a dramatic decrease in blood cellularity that led to death, while the recipients with SFFV-RPS19 shRNA-D bone marrow showed nearly normal blood cellularity. These results demonstrate the potential of enforced expression of RPS19 to reverse the severe anemia and bone marrow failure in DBA. To assess the reconstitution advantage of transduced hematopoietic stem and progenitor cells with time, we performed similar experiments with heterozygous shRNA-D bone marrow cells. We monitored the percentage of GFP-positive myeloid cells in the peripheral blood, which provides a dynamic read-out for bone marrow activity. After four months of doxycycline administration, the mean percentage of GFP-positive cells in the recipients with SFFV-RPS19 heterozygous shRNA-D bone marrow increased to 97 %, while no similar advantage was observed in the recipients with SFFV-RPS19 or SFFV-GFP control bone marrow, or SFFV-GFP heterozygous shRNA-D bone marrow. Consistently, SFFV-RPS19 conferred a reconstitution advantage over the non-transduced cells in the bone marrow. Furthermore, SFFV-RPS19 reversed the hypocellular bone marrow observed in the SFFV-GFP heterozygous shRNA-D recipients. Taken together, using mouse models for RPS19-deficient DBA, we demonstrate that the enforced expression of RPS19 rescues the lethal bone marrow failure and confers a strong reconstitution advantage in vivo. These results provide a proof-of-principle for gene therapy in the treatment of RPS19-deficient DBA. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2476-2476
Author(s):  
Kasia Mierzejewska ◽  
Ewa Suszynska ◽  
Sylwia Borkowska ◽  
Malwina Suszynska ◽  
Maja Maj ◽  
...  

Abstract Background Hematopoietic stem/progenitor cells (HSPCs) are exposed in vivo to several growth factors, cytokines, chemokines, and bioactive lipids in bone marrow (BM) in addition to various sex hormones circulating in peripheral blood (PB). It is known that androgen hormones (e.g., danazol) is employed in the clinic to treat aplastic anemia patients. However, the exact mechanism of action of sex hormones secreted by the pituitary gland or gonads is not well understood. Therefore, we performed a complex series of experiments to address the influence of pregnant mare serum gonadotropin (PMSG), luteinizing hormone (LH), follicle-stimulating hormone (FSH), androgen (danazol) and prolactin (PRL) on murine hematopoiesis. In particular, from a mechanistic view we were interested in whether this effect depends on stimulation of BM-residing stem cells or is mediated through the BM microenvironment. Materials and Methods To address this issue, normal 2-month-old C57Bl6 mice were exposed or not to daily injections of PMSG (10 IU/mice/10 days), LH (5 IU/mice/10 days), FSH (5 IU/mice/10 days), danazol (4 mg/kg/10 days) and PRL (1 mg/day/5days). Subsequently, we evaluated changes in the BM number of Sca-1+Lin–CD45– that are precursors of long term repopulating hematopoietic stem cells (LT-HSCs) (Leukemia 2011;25:1278–1285) and bone forming mesenchymal stem cells (Stem Cell & Dev. 2013;22:622-30) and Sca-1+Lin–CD45+ hematopoietic stem/progenitor cells (HSPC) cells by FACS, the number of clonogenic progenitors from all hematopoietic lineages, and changes in peripheral blood (PB) counts. In some of the experiments, mice were exposed to bromodeoxyuridine (BrdU) to evaluate whether sex hormones affect stem cell cycling. By employing RT-PCR, we also evaluated the expression of cell-surface and intracellular receptors for hormones in purified populations of murine BM stem cells. In parallel, we studied whether stimulation by sex hormones activates major signaling pathways (MAPKp42/44 and AKT) in HSPCs and evaluated the effect of sex hormones on the clonogenic potential of murine CFU-Mix, BFU-E, CFU-GM, and CFU-Meg in vitro. We also sublethally irradiated mice and studied whether administration of sex hormones accelerates recovery of peripheral blood parameters. Finally, we determined the influence of sex hormones on the motility of stem cells in direct chemotaxis assays as well as in direct in vivo stem cell mobilization studies. Results We found that 10-day administration of each of the sex hormones evaluated in this study directly stimulated expansion of HSPCs in BM, as measured by an increase in the number of these cells in BM (∼2–3x), and enhanced BrdU incorporation (the percentage of quiescent BrdU+Sca-1+Lin–CD45– cells increased from ∼2% to ∼15–35% and the percentage of BrdU+Sca-1+Lin–CD45+ cells increased from 24% to 43–58%, Figure 1). These increases paralleled an increase in the number of clonogenic progenitors in BM (∼2–3x). We also observed that murine Sca-1+Lin–CD45– and Sca-1+Lin–CD45+ cells express sex hormone receptors and respond by phosphorylation of MAPKp42/44 and AKT in response to exposure to PSMG, LH, FSH, danazol and PRL. We also observed that administration of sex hormones accelerated the recovery of PB cell counts in sublethally irradiated mice and slightly mobilized HSPCs into PB. Finally, in direct in vitro clonogenic experiments on purified murine SKL cells, we observed a stimulatory effect of sex hormones on clonogenic potential in the order: CFU-Mix > BFU-E > CFU-Meg > CFU-GM. Conclusions Our data indicate for the first time that not only danazol but also several pituitary-secreted sex hormones directly stimulate the expansion of stem cells in BM. This effect seems to be direct, as precursors of LT-HSCs and HSPCs express all the receptors for these hormones and respond to stimulation by phosphorylation of intracellular pathways involved in cell proliferation. These hormones also directly stimulated in vitro proliferation of purified HSPCs. In conclusion, our studies support the possibility that not only danazol but also several other upstream pituitary sex hormones could be employed to treat aplastic disorders and irradiation syndromes. Further dose- and time-optimizing mouse studies and studies with human cells are in progress in our laboratories. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2003 ◽  
Vol 101 (6) ◽  
pp. 2199-2205 ◽  
Author(s):  
Peiman Hematti ◽  
Stephanie E. Sellers ◽  
Brian A. Agricola ◽  
Mark E. Metzger ◽  
Robert E. Donahue ◽  
...  

Gene transfer experiments in nonhuman primates have been shown to be predictive of success in human clinical gene therapy trials. In most nonhuman primate studies, hematopoietic stem cells (HSCs) collected from the peripheral blood or bone marrow after administration of granulocyte colony-stimulating factor (G-CSF) + stem cell factor (SCF) have been used as targets, but this cytokine combination is not generally available for clinical use, and the optimum target cell population has not been systematically studied. In our current study we tested the retroviral transduction efficiency of rhesus macaque peripheral blood CD34+ cells collected after administration of different cytokine mobilization regimens, directly comparing G-CSF+SCF versus G-CSF alone or G-CSF+Flt3-L in competitive repopulation assays. Vector supernatant was added daily for 96 hours in the presence of stimulatory cytokines. The transduction efficiency of HSCs as assessed by in vitro colony-forming assays was equivalent in all 5 animals tested, but the in vivo levels of mononuclear cell and granulocyte marking was higher at all time points derived from target CD34+ cells collected after G-CSF+SCF mobilization compared with target cells collected after G-CSF (n = 3) or G-CSF+Flt3-L (n = 2) mobilization. In 3 of the animals long-term marking levels of 5% to 25% were achieved, but originating only from the G-CSF+SCF–mobilized target cells. Transduction efficiency of HSCs collected by different mobilization regimens can vary significantly and is superior with G-CSF+SCF administration. The difference in transduction efficiency of HSCs collected from different sources should be considered whenever planning clinical gene therapy trials and should preferably be tested directly in comparative studies.


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