Improved Analysis of Hematopoietic Engraftment by Non-Invasive In Vivo Bioluminescent Imaging of Transplanted Human Embryonic Stem Cell-Derived Hematopoietic Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1270-1270
Author(s):  
Jonathan L. Linehan ◽  
Xinghui Tian ◽  
Julie K. Morris ◽  
Dan S. Kaufman
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Es Cells ◽  
Hematopoietic Cells ◽  
Embryonic Stem ◽  
Scid Mice ◽  
Cell Lineages ◽  
Non Invasive ◽  
Flow Cytometric

Abstract Animal transplantation models are essential to characterize the long-term in vivo engraftment capacity of putative hematopoietic stem cells derived from human embryonic stem cells (hESCs). We have previously demonstrated that hESCs can be routinely utilized to derive multiple hematopoietic cell lineages. Here, we use in vivo bioluminescence imaging (BLI) of stable luciferase (luc)-expressing hESCs to noninvasively monitor the dynamics of transplantation, engraftment, and growth of hESC-derived hematopoietic cells within individual animals over an extended time course. Luc expression under control of an EF1α promoter was introduced into the H1 hESC line using a self-inactivating lentiviral vector. Undifferentiated hESC colonies that stably expressed luciferase were established and selected, and the pluripotent capability of luc+ hESCs was first explored by teratoma formation. Undifferentiated luc+ human ES cells were intramuscularly injected into NOD/SCID mice. The dynamics of survival and growth of the hESCs was monitored by BLI using the IVIS Imaging System (Xenogen) at regular time points post-transplantation. There was a decrease of luminescent signal during the first 1–2 weeks. This was followed by a dramatic increase in luminescent signals after about 5 weeks, which correlated with teratoma size. Immunohistochemical analysis confirmed stable luc-expression in multiple differentiated cell types within the teratomas. We next used BLI to examine luc+ H1 hESCs that were induced to undergo hematopoietic differentiation by co-culture with S17 cells, to give rise to H1/S17 cells. Flow cytometric studies confirmed hematopoietic cells (CD34+, CD45+, CD31+, and c-kit+ cells) were derived from these differentiated luc+ hESCs, with 5–10% of H1/S17 cells being CD34+. Hematopoietic progenitors that gave rise to colonies of mature luc+ blood cells in a standard CFU assay were also observed from the H1/S17 cells. Luc-expression of differentiated hESCs was maintained at similar levels to those of the undifferentiated ES cells. To define the in vivo potential of luc+ hESC-derived hematopoietic cells, hESCs were allowed to differentiate on S17 cells for two weeks. SCID-repopulating cell studies were done by intravenous (iv) injection into sublethally irradiated NOD/SCID mice. After iv injection of 2–3 x106 unsorted luc+ H1/S17 cells, BLI showed the brightest signal in the lung at day 0 (within 2 hours), followed by a rapid decline in signal on the next day (day1). On day 8, most luc+ cells were detected in the abdomen and liver. Subsequently, after 6–12 weeks, multiple engraftment loci were identified in hematopoietic tissues. Flow cytometric analysis of bone marrow from these mice confirmed the presence of hESC-derived human CD45+ cells. Engraftment was also demonstrated after direct intra-bone marrow injection with as few as 60,000 CD34+ cells sorted from luc+ H1/S17 cells. Again, stable engraftment can be monitored by BLI for 8+ weeks. These results demonstrate that BLI has several important advantages as an effective non-invasive approach to track and quantitatively monitor in vivo engraftment of hematopoietic or other cell lineages derived from hESCs.

Reprogrammed Murine Fibroblasts Differentiated into Hematopoietic Progenitors Are Able to Successfully Engraft and Repopulate the Bone Marrow

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 389-389 ◽  
Author(s):  
Zaida Alipio ◽  
Dan Xu ◽  
Jianchang Yang ◽  
Louis M. Fink ◽  
Wilson Xu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Es Cells ◽  
Hematopoietic Cells ◽  
Embryonic Stem ◽  
Ips Cells ◽  
Embryoid Bodies ◽  
Hematopoietic Progenitors

Abstract Cellular therapy using embryonic stem cells has always been an area of great interest due to the pluripotent characteristics of stem cells. In 2006, Takahashi and Yamanaka (Cell 126, 663–676) demonstrated that somatic cells can be reprogrammed into a stem cell-like state, termed induced pluripotent stem (iPS) cells, by ectopic expression of Oct4, Sox2, Klf4 and c Myc. A later report (Nakagawa et al. Nat. Biotechnol.26:101–106, 2008) showed that iPS cells can be produced in the absence of the c Myc oncogene. We have used this latter strategy to successfully reprogram somatic cells derived from C57BL/6 mouse tail fibroblast to iPS cells. Retrovirus infected fibroblasts exhibited stem cell-like morphology by 14 days post infection. These iPS cells were then infected with a retrovirus that expressed HOXB4. Recombinant leukemia inhibitor factor (LIF) supplement was removed from media at this time and the cells allowed to differentiate into embryoid bodies. These cells were screened for specific differentiation stem cell markers, such as Oct4, Nanog, Sall4 and SSEA-1. iPS cells were converted into embryonic bodies and then infected with retroviruses expressing HOXB4. Embryoid bodies stably expressing HOXB4 were induced to hematopoietic differentiation by treatment of thrombopoietin (TPO), stem cell factor (SCF), vascular endothelial growth factor (VEGF), interferon gamma (IFNg) and fms-like tyrosine kinase (FLT3 ligand). Evaluation of iPS-derived hematopoietic cells on smears show strikingly similarity in morphology to the W4 mouse embryonic stem (ES) cells differentiated into hematopoietic cells as a control. Flow cytometry analysis of iPS-derived hematopoietic cells after 1 week exposure to cytokines revealed 7% B220+ cells (B cells), 11% Ter119+ cells (erythroid), and 13% Gr-1+ cells (granulocytes) similar to W4 ES cells. The iPS-derived hematopoietic cells were transplanted into irradiated immunodeficient mice via lateral tail vein injection. Transplantation of these iPS-derived hematopoietic progenitors tagged with GFP into irradiated SCID mice revealed that the hematopoietic progenitors were able to home to the bone marrow after 1 week of transplantation. Importantly, after 1 month, GFP+ engrafted cells remained in the bone marrow suggesting a long-term engraftment. This long term engraftment of the iPS-derived hematopoietic cells to the bone marrow constitutes an important step toward potential therapy of numerous patient-specific blood based diseases.

scholarly journals In Vivo Generation of Bone Marrow from Embryonic Stem Cells in Interspecies Chimeras

2021 ◽  
Author(s):  
Bingqiang Wen ◽  
Guolun Wang ◽  
Enhong Li ◽  
Olena A. Kolesnichenko ◽  
Zhaowei Tu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Embryonic Stem Cells ◽  
Progenitor Cells ◽  
Embryonic Stem ◽  
Hematopoietic Cell ◽  
Mouse Escs ◽  
Cell Therapies ◽  
Cell Lineages

Generation of bone marrow (BM) from embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs) promises to accelerate the development of future cell therapies for life-threatening disorders. However, such approach is limited by technical challenges to produce a mixture of functional BM progenitor cells able to replace all hematopoietic cell lineages. Herein, we used blastocyst complementation to simultaneously produce all BM hematopoietic cell lineages from mouse ESCs in a rat. Based on FACS analysis and single-cell RNA sequencing, mouse ESCs differentiated into hematopoietic progenitor cells and multiple hematopoietic cell types that were indistinguishable from normal mouse BM cells based on gene expression signatures and cell surface markers. Transplantation of ESC-derived BM cells from mouse-rat chimeras rescued lethally-irradiated syngeneic mice and resulted in long-term contribution of donor cells to hematopoietic cell lineages. Altogether, a fully functional bone marrow was generated from mouse ESCs using rat embryos as “bioreactors”.

Overexpression of HOXB4 enhances the hematopoietic potential of embryonic stem cells differentiated in vitro

Blood ◽  
1996 ◽  
Vol 87 (7) ◽  
pp. 2740-2749 ◽  
Author(s):  
CD Helgason ◽  
G Sauvageau ◽  
HJ Lawrence ◽  
C Largman ◽  
RK Humphries
Keyword(s):  
Stem Cells ◽  
Es Cells ◽  
Hematopoietic Cells ◽  
Embryonic Stem ◽  
Homeobox Genes ◽  
Embryoid Bodies ◽  
Proliferative Potential ◽  
Hematopoietic Stem ◽  
Differentiation And Proliferation

Little is known about the molecular mechanisms controlling primitive hematopoietic stem cells, especially during embryogenesis. Homeobox genes encode a family of transcription factors that have gained increasing attention as master regulators of developmental processes and recently have been implicated in the differentiation and proliferation of hematopoietic cells. Several Hox homeobox genes are now known to be differentially expressed in various subpopulations of human hematopoietic cells and one such gene, HOXB4, has recently been shown to positively determine the proliferative potential of primitive murine bone marrow cells, including cells with long-term repopulating ability. To determine if this gene might influence hematopoiesis at the earliest stages of development, embryonic stem (ES) cells were genetically modified by retroviral gene transfer to overexpress HOXB4 and the effect on their in vitro differentiation was examined. HOXB4 overexpression significantly increased the number of progenitors of mixed erythroid/myeloid colonies and definitive, but not primitive, erythroid colonies derived from embryoid bodies (EBs) at various stages after induction of differentiation. There appeared to be no significant effect on the generation of granulocytic or monocytic progenitors, nor on the efficiency of EB formation or growth rate. Analysis of mRNA from EBs derived from HOXB4-transduced ES cells on different days of primary differentiation showed a significant increase in adult beta-globin expression, with no detectable effect on GATA-1 or embryonic globin (beta H-1). Thus, HOXB4 enhances the erythropoietic, and possibly more primitive, hematopoietic differentiative potential of ES cells. These results provide new evidence implicating Hox genes in the control of very early stages in the development of the hematopoietic system and highlight the utility of the ES model for gaining insights into the molecular genetic regulation of differentiation and proliferation events.

230 GENERATION OF PUTATIVE RABBIT EMBRYONIC STEM CELLS

2007 ◽  
Vol 19 (1) ◽  
pp. 231
Author(s):  
S. Wang ◽  
X. Tang ◽  
Y. Niu ◽  
H. Chen ◽  
T. Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
High Speed ◽  
Es Cells ◽  
Research Work ◽  
Embryonic Stem ◽  
Morphological Characteristics ◽  
Mouse Escs

The rabbit, as a laboratory animal model, has several advantages in the study of human physiological disorders. In this study, stable putative pluripotent rabbit embryonic stem cells (rESCs) were derived from in vivo-fertilized and in vitro-cultured blastocysts. The rabbit ICMs were obtained by 0.05% trypsin–0.008% EDTA treatment and mechanical separation; the ES-like cell colonies seen several days later. ICM-derived outgrowths which were treated with 5 mg/mL-1 dispase, followed by 0.05% trypsin–0.008% EDTA, were mechanically disaggregated into small clumps and reseeded on MEFs. The putative ES cell lines maintained expression of pluripotent cells markers and normal XY karyotype for long periods of culture (>1 month). The putative rESCs expressed alkaline phosphatase, transcription factor Oct-4, stage-specific embryonic antigens (SSEA-1, SSEA-3, and SSEA-4), and tumor-related antigens (TRA-1-60 and TRA-1-81). The morphological characteristics of the putative ESCs are closer to those of human ESCs; their high speed of proliferation, however, is closer to that of mouse ESCs. Putative rabbit ESCs were induced to differentiate into many cell types including trophoblast cells, similar to primate ESCs, in vitro, and formed teratomas with derivatives of the 3 major germ layers in vivo when injected into SCID mice. Using RT-PCR measurement, but with some differences in ligands and inhibitors, and comparing with human and mouse ESCs, the putative rabbit ESCs expressed similar genes related to pluripotency (Oct-4, Nanog, SOX2, and UTF-1) and similar genes of FGF, WNT, and TGF signaling pathways related to the proliferation and self-renewal. Our further research work showed that TGF beta and FGF pathways cooperate to maintain pluripotency of rabbit ESCs similar to those of human ES cells.

Gene transfer into normal human hematopoietic cells using in vitro and in vivo assays

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 624-634 ◽  
Author(s):  
JE Dick ◽  
S Kamel-Reid ◽  
B Murdoch ◽  
M Doedens
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Gene Transfer ◽  
Hematopoietic Cells ◽  
Human Stem Cells ◽  
In Vivo Assays ◽  
Genetically Manipulated ◽  
Deficient Mice

Abstract The ability to transfer new genetic material into human hematopoietic cells provides the foundation for characterizing the organization and developmental program of human hematopoietic stem cells. It also provides a valuable model in which to test gene transfer and long-term expression in human hematopoietic cells as a prelude to human gene therapy. At the present time such studies are limited by the absence of in vivo assays for human stem cells, although recent descriptions of the engraftment of human hematopoietic cells in immune-deficient mice may provide the basis for such an assay. This study focuses on the establishment of conditions required for high efficiency retrovirus- mediated gene transfer into human hematopoietic progenitors that can be assayed in vitro in short-term colony assays and in vivo in immune- deficient mice. Here we report that a 24-hour preincubation of human bone marrow in 5637-conditioned medium, before infection, increases gene transfer efficiency into in vitro colony-forming cells by sixfold; interleukin-6 (IL-6) and leukemia inhibitory factor (LIF) provide the same magnitude increase as 5637-conditioned medium. In contrast, incubation in recombinant growth factors IL-1, IL-3, and granulocyte- macrophage colony-stimulating factor increases gene transfer efficiency by 1.5- to 3-fold. Furthermore, preselection in high concentrations of G418 results in a population of cells significantly enriched for G418- resistant progenitors (up to 100%). These results, obtained using detailed survival curves based on colony formation in G418, have been substantiated by directly detecting the neo gene in individual colonies using the polymerase chain reaction. Using these optimized protocols, human bone marrow cells were genetically manipulated with a neo retrovirus vector and transplanted into immune-deficient bg/nu/xid mice. At 1 month and 4 months after the transplant, the hematopoietic tissues of these animals remained engrafted with genetically manipulated human cells. More importantly, G418-resistant progenitors that contained the neo gene were recovered from the bone marrow and spleen of engrafted animals after 4 months. These experiments establish the feasibility of characterizing human stem cells using the unique retrovirus integration site as a clonal marker, similar to techniques developed to elucidate the murine stem cell hierarchy.

Enforced Expression of the GATA-2 Transcription Factor Blocks Normal Hematopoiesis

Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 488-499 ◽  
Author(s):  
Derek A. Persons ◽  
James A. Allay ◽  
Esther R. Allay ◽  
Richard A. Ashmun ◽  
Donald Orlic ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Transcription Factor ◽  
Blood Cell ◽  
Fluorescent Protein ◽  
Bone Marrow Cells ◽  
Hematopoietic Cells ◽  
Immunoblot Analysis ◽  
Marrow Cells

Abstract The zinc finger transcription factor GATA-2 is highly expressed in immature hematopoietic cells and declines with blood cell maturation. To investigate its role in normal adult hematopoiesis, a bicistronic retroviral vector encoding GATA-2 and the green fluorescent protein (GFP) was used to maintain the high levels of GATA-2 that are normally present in primitive hematopoietic cells. Coexpression of the GFP marker facilitated identification and quantitation of vector-expressing cells. Bone marrow cells transduced with the GATA-2 vector expressed GFP as judged by flow cytometry and GATA-2 as assessed by immunoblot analysis. A 50% to 80% reduction in hematopoietic progenitor-derived colony formation was observed with GATA-2/GFP-transduced marrow, compared with marrow transduced with a GFP-containing vector lacking the GATA-2 cDNA. Culture of purified populations of GATA-2/GFP-expressing and nonexpressing cells confirmed a specific ablation of the colony-forming ability of GATA-2/GFP-expressing progenitor cells. Similarly, loss of spleen colony-forming ability was observed for GATA-2/GFP-expressing bone marrow cells. Despite enforced GATA-2 expression, marrow cells remained viable and were negative in assays to evaluate apoptosis. Although efficient transduction of primitive Sca-1+Lin- cells was observed with the GATA-2/GFP vector, GATA-2/GFP-expressing stem cells failed to substantially contribute to the multilineage hematopoietic reconstitution of transplanted mice. Additionally, mice transplanted with purified, GATA-2/GFP-expressing cells showed post-transplant cytopenias and decreased numbers of total and gene-modified bone marrow Sca-1+ Lin−cells. Although Sca-1+ Lin− bone marrow cells expressing the GATA-2/GFP vector were detected after transplantation, no appreciable expansion in their numbers occurred. In contrast, control GFP-expressing Sca-1+Lin− cells expanded at least 40-fold after transplantation. Thus, enforced expression of GATA-2 in pluripotent hematopoietic cells blocked both their amplification and differentiation. There appears to be a critical dose-dependent effect of GATA-2 on blood cell differentiation in that downregulation of GATA-2 expression is necessary for stem cells to contribute to hematopoiesis in vivo.

Exhaustion of Donor Hematopoietic Stem Cells in Lethally-Irradiated Hosts Can Be Sbstantially Mitigated by Targeting p18INK4C.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1200-1200
Author(s):  
Hui Yu ◽  
Youzhong Yuan ◽  
Xianmin Song ◽  
Feng Xu ◽  
Hongmei Shen ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Kinase Inhibitor ◽  
Hematopoietic Cells ◽  
Hematopoietic Stem ◽  
Total Period ◽  
Over Expression

Abstract Hematopoietic stem cells (HSCs) are significantly restricted in their ability to regenerate themselves in the irradiated hosts and this exhausting effect appears to be accelerated in the absence of the cyclin-dependent kinase inhibitor (CKI), p21. Our recent study demonstrated that unlike p21 absence, deletion of the distinct CKI, p18 results in a strikingly positive effect on long-term engraftment owing to increased self-renewing divisions in vivo (Yuan et al, 2004). To test the extent to which enhanced self-renewal in the absence of p18 can persist over a prolonged period of time, we first performed the classical serial bone marrow transfer (sBMT). The activities of hematopoietic cells from p18−/− cell transplanted mice were significantly higher than those from p18+/+ cell transplanted mice during the serial transplantation. To our expectation, there was no detectable donor p18+/+ HSC progeny in the majority (4/6) of recipients after three rounds of sBMT. However, we observed significant engraftment levels (66.7% on average) of p18-null progeny in all recipients (7/7) within a total period of 22 months. In addition, in follow-up with our previous study involving the use of competitive bone marrow transplantation (cBMT), we found that p18−/− HSCs during the 3rd cycle of cBMT in an extended long-term period of 30 months were still comparable to the freshly isolated p18+/+ cells from 8 week-old young mice. Based on these two independent assays and the widely-held assumption of 1-10/105 HSC frequency in normal unmanipulated marrow, we estimated that p18−/− HSCs had more than 50–500 times more regenerative potential than p18+/+ HSCs, at the cellular age that is equal to a mouse life span. Interestingly, p18 absence was able to significantly loosen the accelerated exhaustion of hematopoietic repopulation caused by p21 deficiency as examined in the p18/p21 double mutant cells with the cBMT model. This data directly indicates the opposite effect of these two molecules on HSC durability. To define whether p18 absence may override the regulatory mechanisms that maintain the HSC pool size within the normal range, we performed the transplantation with 80 highly purified HSCs (CD34-KLS) and then determined how many competitive reconstitution units (CRUs) were regenerated in the primary recipients by conducting secondary transplantation with limiting dilution analysis. While 14 times more CRUs were regenerated in the primary recipients transplanted with p18−/−HSCs than those transplanted with p18+/+ HSCs, the level was not beyond that found in normal non-transplanted mice. Therefore, the expansion of HSCs in the absence of p18 is still subject to some inhibitory regulation, perhaps exerted by the HSC niches in vivo. Such a result was similar to the effect of over-expression of the transcription factor, HoxB4 in hematopoietic cells. However, to our surprise, the p18 mRNA level was not significantly altered by over-expression of HoxB4 in Lin-Sca-1+ cells as assessed by real time PCR (n=4), thereby suggesting a HoxB4-independent transcriptional regulation on p18 in HSCs. Taken together, our current results shed light on strategies aimed at sustaining the durability of therapeutically transplanted HSCs for a lifetime treatment. It also offers a rationale for the feasibility study intended to temporarily target p18 during the early engraftment for therapeutic purposes.

Hematopoietic Cell Differentiation from Common Marmoset (Callithrix jacchus) Embryonic Stem Cells by Their Genetic Manipulation Using the Third Generation Lentiviral Vector.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 495-495
Author(s):  
Ryo Kurita ◽  
Erika Sasaki ◽  
Takashi Hiroyama ◽  
Tomoko Yokoo ◽  
Yukoh Nakazaki ◽  
...  
Keyword(s):  
Cell Therapy ◽  
Es Cells ◽  
Hematopoietic Cells ◽  
Embryonic Stem ◽  
Culture Conditions ◽  
Preclinical Studies ◽  
Es Cell ◽  
Hematopoietic Stem

Abstract Since the successful establishment of human embryonic stem (ES) cell lines in 1998, transplantation of differentiated ES cells to specific organ has been expected to complete its defective function. For the realistic medicine, the preclinical studies using animal model systems including non-human primates are essential. We have already demonstrated that non-human primates of common marmosets (CM) are suitable for the laboratory animal models for preclinical studies of hematopoietic stem cell therapy. In this study, we investigated the in vitro and in vivo differentiation of CM ES cells to hematopoietic cells by exogenous gene transfer methods in order to study the feasibility of future gene modified ES cell therapy. First, we tried various in vitro culture conditions including systems using embryoid bodies or co-culturing with stromal cells to induce hematopoietic cells, but the frequency of inducing hematopoietic cells was very low. The expression of CD45 and gata1 could not be detected in both conditions, suggesting that our culture conditions were incomplete for induction of hematopoietic cells from CM ES cells. Next we examined gene transduction methods by using VSV-G pseudotyped human immunodeficiency virus (HIV) vectors. We constructed the HIV vectors containing hematopoietic genes such as tal1/scl, gata1, gata2, hoxB4 and Lh2 genes under the EF1a promoter and transduced them into CM ES cells. Only in the case of tal1/scl overexpression, not other genes, hematopoietic induction from CM ES cells was dramatically increased and multi-lineage blood cells consisting of erythroid cells, granulocytes, macrophages and megakaryocytes, were confirmed by immunochemical and morphological analyses. Furthermore, RT-PCR results showed that several hematopoietic marker genes including CD34 were expressed higher in the tal1/scl overexpressed ES-derived cells. After the xenotransplantation of ES-derived cells into the immunodeficient mice, CM CD45+ cells and immature erythroids and megakaryocytic cells were observed only in the ES-tal1-injected mice, indicating that enforced expression of tal1/scl into ES cells led to highly efficient hematopoietic cell differentiation in vivo. Taken together, it was suggested that the transduction of exogenous tal1/scl cDNA into ES cells by HIV vector was the promising method for the efficient differentiation from CM ES cells to hematopoietic stem cells. Further examinations are required to determine the long-term hematopoietic reconstitute capacity and the safety of the tal1/scl transduced ES cells in marmoset for the purpose of developing new hematopoietic stem cell therapy.

Induced Hematopoietic Differentiation Of Common Marmoset Embryonic Stem Cells By LYL1 Can Give Rise To Hematopoietic Stem Cells Having The Enhanced Bone Marrow Reconstitution Capability

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1192-1192
Author(s):  
Hirotaka Kawano ◽  
Tomotoshi Marumoto ◽  
Takafumi Hiramoto ◽  
Michiyo Okada ◽  
Tomoko Inoue ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Lymphoblastic Leukemia ◽  
Embryonic Stem ◽  
Hematopoietic Differentiation ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Hsc Transplantation

Abstract Hematopoietic stem cell (HSC) transplantation is the most successful cellular therapy for the malignant hematopoietic diseases such as leukemia, and early recovery of host’s hematopoiesis after HSC transplantation has eagerly been expected to reduce the regimen related toxicity for many years. For the establishment of the safer and more efficient cell source for allogeneic or autologous HSC transplantation, HSCs differentiated from embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs) that show indefinite proliferation in an undifferentiated state and pluripotency, are considered to be one of the best candidates. Unfortunately, despite many recent efforts, the HSC-specific differentiation from ESCs and iPSCs remains poor [Kaufman, DS et al., 2001][Ledran MH et al., 2008]. In this study, we developed the new method to differentiate HSC from non-human primate ESC/iPSC. It has been reported that common marmoset (CM), a non-human primate, is a suitable experimental animal for the preclinical studies of HSC therapy [Hibino H et al., 1999]. We have been investigated the hematopoietic differentiation of CM ESCs into HSCs, and previously reported that the induction of CD34+ cells having a blood colony forming capacity from CM ESCs were promoted by lentiviral transduction of TAL1 cDNA [Kurita R et al., 2006]. However, those CD34+ cells did not have a bone marrow reconstituting ability in irradiated NOG (NOD/Shi-scid/IL-2Rγnull) mice, suggesting that transduction of TAL1 gene was not sufficient to induce functional HSCs which have self-renewal capability and multipotency. Thus, we tried to find other hematopoietic genes being able to promote hematopoietic differetiation more efficiently than TAL1. We selected 6 genes (LYL1, HOXB4, BMI1, GATA2, c-MYB and LMO2) as candidates for factors that induce the differentiation of ESCs into HSCs, based on the previous study of hematopoietic differentiation from human and mouse ESCs. And CM ESCs (Cj11) lentivirally transduced with the respective candidate gene were processed for embryoid body (EB) formation to induce their differentiation into HSCs for 9 days. We found that lentiviral transduction of LYL1 (lymphoblastic leukemia 1), a basic helix-loop-helix transcription factor, in EBs markedly increased the proportion of cells positive for CD34 (approximately 20% of LYL1-transduced cells). RT-PCR showed that LYL1-transduced EBs expressed various hematopoietic genes, such as TAL1, RUNX1 and c-KIT. To examine whether these CD34+ cells have the ability to differentiate into hematopoietic cells in vitro, we performed colony-forming unit (CFU) assay, and found that CD34+ cells in LYL1-transduced EBs could form multi-lineage blood colonies. Furthermore the number of blood colonies originated from CD34+CD45+ cells in LYL1-transduced EBs was almost the same as that from CD34+CD45+ cells derived from CM bone marrow. These results suggested that enforced expression of LYL1 in CM ESCs promoted the emergence of HSCs by EB formation in vitro. The LYL1 was originally identified as the factor of a chromosomal translocation, resulting in T cell acute lymphoblastic leukemia [Mellentin JD et al., 1989]. The Lyl1-deficient mice display the reduction of B cells and impaired long-term hematopoietic reconstitution capacity [Capron C et al., 2006]. And, transduction of Lyl1 in mouse bone marrow cells induced the increase of HSCs and lymphocytes in vitro and in vivo [Lukov GL et al., 2011]. Therefore we hypothesized that LYL1 may play essential roles in bone marrow reconstitution by HSCs differentiated from CM ESCs. To examine this, we transplanted CD34+ cells derived from LYL1-transduced CM ESCs into bone marrow of sublethally irradiated NOG mice, and found that about 7% of CD45+ cells derived from CM ESCs were detected in peripheral blood (PB) of recipient mice at 8 weeks after transplant (n=4). Although CM CD45+ cells disappeared at 12 weeks after transplant, CD34+ cells (about 3%) were still found in bone marrow at the same time point. Given that TAL1-transduced EBs derived from CM ESCs could not reconstitute bone marrow of irradiated mice at all, LYL1 rather than TAL1 might be a more appropriate transcription factor that can give rise to CD34+ HSCs having the enhanced capability of bone marrow reconstitution from CM ESCs. We are planning to do in vivo study to prove this hypothesis in CM. Disclosures: No relevant conflicts of interest to declare.

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