scholarly journals Novel population of human monocyte and osteoclast progenitors from pluripotent stem cells and peripheral blood

2021 ◽  
Author(s):  
Sierra Hope Root ◽  
Hector Leonardo Aguila
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Dendritic Cells ◽  
Pluripotent Stem Cells ◽  
Peripheral Blood ◽  
Human Peripheral Blood ◽  
Human Monocyte ◽  
Double Positive

Osteoclasts are multi-nuclear cells of monocytic lineage, with the ability to resorb bone. Studies in mouse have identified bone marrow clonal progenitors able to generate mature osteoclast cells (OCs) in vitro and in vivo. These osteoclast progenitors (OCPs) can also generate macrophages and dendritic cells. Interestingly, cells with equivalent potential can be detected in periphery. In humans, cells with OCP activity have been identified in bone marrow and periphery. However, their characterization has not been as extensive. We have developed reproducible methods to derive, from human pluripotent stem cells, a population containing monocyte progenitors able to generate functional OCs. Within this population, we have identified cells with monocyte and osteoclast progenitor activity based on CD11b and CD14 expression. A population double positive (DP) for CD11b and CD14 contains cells with expected osteoclastic potential. However, the double negative (DN) population, containing most of the hematopoietic progenitor activity, also presents a very high osteoclastic potential. These progenitor cells can also be differentiated to macrophage and dendritic cells. Further dissection within the DN population, identified cells bearing the phenotype: CD15-CD115+ as the population with highest monocytic progenitor and osteoclastic potential. When similar methodology was used to identify OCPs from human peripheral blood, we confirmed a published OCP population with the phenotype CD11b+CD14+. In addition, we identified a second population (CD14-CD11bloCD115+) with high monocytic progenitor activity and also able to form osteoclast like (OCL) cells, similar to the two populations identified from pluripotent stem cells.

Abstract 697: Mobilization of Oct-4 + Bone Marrow-Derived Very Small Embryonic-Like Stem Cells in Patients with Acute Myocardial Infarction

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Wojciech Wojakowski ◽  
Magda Kucia ◽  
Boguslaw Machalinski ◽  
Edyta Paczkowska ◽  
Joanna Ciosek ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Stem Cells ◽  
Bone Marrow ◽  
Pluripotent Stem Cells ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Small Cells ◽  
Acute Mi

Bone marrow-derived CD34 + CXCR4 + progenitor cells are mobilized into peripheral blood early in acute myocardial infarction (MI). Adult murine bone marrow contains population of small CD34 + lin − CD45 − CXCR4 + cells expressing markers of pluripotent stem cells (PSC) SSEA, Oct-4 and Nanog. This population of very small embryonic-like cells (VSEL) has unique morphology (small size 2– 4 μm, large nucleus, euchromatin) and capability to form embrioid bodies (EB). Murine EB-derived cells can in vitro differentiate into cells from all three germ layers including cardiomyocytes. We hypothesized that in patients with acute MI small cells expressing the VSEL immunophenotype and PSC markers are present in bone marrow and mobilized into peripheral blood. Blood samples (20 mL) from 18 patients with acute MI were obtained after 12 hours, 2 and 5 days after symptoms onset. Bone marrow samples (20 mL) were obtained from 2 patients with acute MI and 3 healthy volunteers. Mononuclear cells were isolated using hypotonic lysis and samples were analyzed by FACS. Mobilization of following cell populations was confirmed: hematopoietic lin − CD45 + CXCR4 + , lin − CD45 + CD133 + , lin − CD45 + CD34 + and non-hematopoietic (VSEL) lin − CD45 − CXCR4 + , lin − CD45 − CD133 + , lin − CD45 − CD34 + . Analysis of the cell number using lymphocyte gate showed more significant increase of CD45 + (hematopoietic) populations of lin − CD34 + , lin − CD133 + and lin − CXCR4 + cells. After gating for small events (VSEL size range) we found more significant mobilization of small, non-hematopoietic populations of lin − CD34 + , lin − CD133 + and lin − CXCR4 + cells (Table ). The expression of PSC markers (Oct-4, Nanog, SSEA-1) in VSEL was confirmed using real-time RT-PCR. Conclusion: We report for the first time that acute MI is associated with mobilization of non-hematopoietic VSELs expressing pluripotent stem cells markers.

scholarly journals Pasteurella multocida Toxin Activates Human Monocyte-Derived and Murine Bone Marrow-Derived Dendritic Cells In Vitro but Suppresses Antibody Production In Vivo

2005 ◽  
Vol 73 (1) ◽  
pp. 413-421 ◽  
Author(s):  
Kenneth C. Bagley ◽  
Sayed F. Abdelwahab ◽  
Robert G. Tuskan ◽  
George K. Lewis
Keyword(s):  
Bone Marrow ◽  
Dendritic Cells ◽  
Phospholipase C ◽  
Cholera Toxin ◽  
Pasteurella Multocida ◽  
Human Monocyte ◽  
Mouse Bone Marrow ◽  
Dependent Manner

ABSTRACT Pasteurella multocida toxin (PMT) is a potent mitogen for fibroblasts and osteoblastic cells. PMT activates phospholipase C-β through Gqα, and the activation of this pathway is responsible for its mitogenic activity. Here, we investigated the effects of PMT on human monocyte-derived dendritic cells (MDDC) in vitro and show a novel activity for PMT. In this regard, PMT activates MDDC to mature in a dose-dependent manner through the activation of phospholipase C and subsequent mobilization of calcium. This activation was accompanied by enhanced stimulation of naïve alloreactive T cells and dominant inhibition of interleukin-12 production in the presence of saturating concentrations of lipopolysaccharide. Surprisingly, although PMT mimics the activating effects of cholera toxin on human MDDC and mouse bone marrow-derived dendritic cells, we found that PMT is not a mucosal adjuvant and that it suppresses the adjuvant effects of cholera toxin in mice. Together, these results indicate discordant effects for PMT in vitro compared to those in vivo.

Disruption of GAS6-MER Pathway Leads to Defects in Physiological Clearance of Expelled Nuclei from Erythroblasts by Bone Marrow Macrophages

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 499-499
Author(s):  
Linda Kadi ◽  
Laurent Burnier ◽  
Rocco Sugamele ◽  
Peter Carmeliet ◽  
Greg Lemke ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Fetal Liver ◽  
Specific Gene ◽  
Positive Staining ◽  
Morphological Examination ◽  
Double Positive ◽  
Blood Island

Abstract Late in erythropoiesis, nuclei are expelled from erythroblasts and 2×1011 anucleated new red blood cells are daily delivered in the peripheral blood. Expelled nuclei expose phosphatidylserine (PS) on their surface, which is used as an “eat me” signal for their engulfment by macrophages located in the blood island. The two PS opsonins, milk-fatglobule EGF8 (MFG-E8) and Growth arrest-specific gene 6 product (GAS6) together with their respective receptors αvβ5/αvβ3 and TAM (TYRO3, AXL and MER), are involved in the phagocytosis of apoptotic cells, but their role in the phagocytosis of expelled nuclei from erythroblasts is not determined. Because fetal liver and bone marrow macrophages do not express MFG-E8, the GAS6-MER pathway might constitute a crucial pathway for the engulfment of nuclei expelled from erythroblasts. To test this hypothesis, we isolated nuclei from late-stage erythroblasts from spleens of phlebotomized mice, and studied nuclei internalization capacity of bone marrow derived macrophages (BMDM) from mice deficient either in GAS6 (GAS6−/−), AXL (AXL−/−) or TYRO3 (TYRO3−/−), or lacking MER kinase domain (MERkd). Released nuclei were identified by flow cytometry according to their size and their double positive staining for the erythroid lineage marker Ter119 and Annexin V for PS. Purity of the preparation was checked by morphological examination of cytospin preparations. In vitro phagocytosis assays show that GAS6−/− BMDM cleared 30% less nuclei than wild-type (WT) BMDM. We observed a slight decrease of internalization capacity for AXL−/− BMDM, whereas TYRO3−/− BMDM engulfed the nuclei as efficiently as WT BMDM. In contrast, MER deficiency nearly abolished nuclei phagocytosis. AXL−/−/TYRO3−/− and AXL−/−/MERkd BMDM were tested and did not show any cumulative effects when compared to WT and single knockouts. We also investigated the signalling pathway downstream of MER in BMDM. In particular, we assessed the expression of the activated form of Rac1, which is crucial for the cytoskeletal reorganization in phagocytosis. Activation of Rac1 after the initiation of the phagocytosis was delayed for 45 minutes in MERkd as compared to WT BMDM. In vivo, we found an accumulation of nuclei in MERkd mice 4 days post phlebotomy, when erythropoiesis is increased in response to anemia. Nuclei circulated in the blood of MERkd mice at a level of 0.08 ± 0.042 G/L and were identified on peripheral blood smears of these mice whereas they were undetectable in the blood of WT mice. We demonstrated an increase of a double labelled Ter119/AnnexinV population corresponding to nuclei in BM (2-fold) and spleen (1.5-fold) of MERkd mice as compared to WT mice. The augmentation of this double labelled population in the MERkd mice translated the phenotype of splenomegaly of these mice. Hematocrit and reticulocyte levels were comparable between WT and MERkd as previously reported (JCI118:583–596, 2008). Thus, MER was critical for in vitro phagocytosis of nuclei from erythroblasts whereas the role of AXL and TYRO3 appeared to be negligible. GAS6 binding to nuclei exposing PS on their surface might form a bridge between PS and MER receptor on BMDM, allowing nuclei clearance. In vivo, the absence of MER caused an accumulation of nuclei in BM and spleen and their appearance in circulating blood due to their inefficient elimination during erythropoietic response to anemia. In conclusion, we postulate that GAS6 and its receptor MER were involved in late erythropoiesis when nuclei are expelled from the erythroblasts and engulfed by BMDM in the blood island, through Rac1 activation.

Cripto Selectively Expands a Distinct Population of Hematopoietic Stem Cells Expressing the Cell Surface Receptor GRP78 and Strongly Induces An Immature Phenotype In Vivo After Ex Vivo Culture

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 405-405
Author(s):  
Kenichi Miharada ◽  
Göran Karlsson ◽  
Jonas Larsson ◽  
Emma Larsson ◽  
Kavitha Siva ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Peripheral Blood ◽  
Distinct Population ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Total Bone Marrow

Abstract Abstract 405 Cripto is a member of the EGF-CFC soluble protein family and has been identified as an important factor for the proliferation/self-renewal of ES and several types of tumor cells. The role for Cripto in the regulation of hematopoietic cells has been unknown. Here we show that Cripto is a potential new candidate factor to increase self-renewal and expand hematopoietic stem cells (HSCs) in vitro. The expression level of Cripto was analyzed by qRT-PCR in several purified murine hematopoietic cell populations. The findings demonstrated that purified CD34-KSL cells, known as highly concentrated HSC population, had higher expression levels than other hematopoietic progenitor populations including CD34+KSL cells. We asked how Cripto regulates HSCs by using recombinant mouse Cripto (rmCripto) for in vitro and in vivo experiments. First we tested the effects of rmCripto on purified hematopoietic stem cells (CD34-LSK) in vitro. After two weeks culture in serum free media supplemented with 100ng/ml of SCF, TPO and 500ng/ml of rmCripto, 30 of CD34-KSL cells formed over 1,300 of colonies, including over 60 of GEMM colonies, while control cultures without rmCripto generated few colonies and no GEMM colonies (p<0.001). Next, 20 of CD34-KSL cells were cultured with or without rmCripto for 2 weeks and transplanted to lethally irradiated mice in a competitive setting. Cripto treated donor cells showed a low level of reconstitution (4–12%) in the peripheral blood, while cells cultured without rmCripto failed to reconstitute. To define the target population and the mechanism of Cripto action, we analyzed two cell surface proteins, GRP78 and Glypican-1, as potential receptor candidates for Cripto regulation of HSC. Surprisingly, CD34-KSL cells were divided into two distinct populations where HSC expressing GRP78 exhibited robust expansion of CFU-GEMM progenitor mediated by rmCripto in CFU-assay whereas GRP78- HSC did not respond (1/3 of CD34-KSL cells were GRP78+). Furthermore, a neutralization antibody for GRP78 completely inhibited the effect of Cripto in both CFU-assay and transplantation assay. In contrast, all lineage negative cells were Glypican-1 positive. These results suggest that GRP78 must be the functional receptor for Cripto on HSC. We therefore sorted these two GRP78+CD34-KSL (GRP78+HSC) and GRP78-CD34-KSL (GRP78-HSC) populations and transplanted to lethally irradiated mice using freshly isolated cells and cells cultured with or without rmCripto for 2 weeks. Interestingly, fresh GRP78-HSCs showed higher reconstitution than GRP78+HSCs (58–82% and 8–40%, p=0.0038) and the reconstitution level in peripheral blood increased rapidly. In contrast, GRP78+HSC reconstituted the peripheral blood slowly, still at a lower level than GRP78-HSC 4 months after transplantation. However, rmCripto selectively expanded (or maintained) GRP78+HSCs but not GRP78-HSCs after culture and generated a similar level of reconstitution as freshly transplanted cells (12–35%). Finally, bone marrow cells of engrafted recipient mice were analyzed at 5 months after transplantation. Surprisingly, GRP78+HSC cultured with rmCripto showed higher reconstitution of the CD34-KSL population in the recipients' bone marrow (45–54%, p=0.0026), while the reconstitution in peripheral blood and in total bone marrow was almost the same. Additionally, most reconstituted CD34-KSL population was GRP78+. Interestingly freshly transplanted sorted GRP78+HSC and GRP78-HSC can produce the GRP78− and GRP78+ populations in the bone marrow and the ratio of GRP78+/− cells that were regenerated have the same proportion as the original donor mice. Compared to cultured cells, the level of reconstitution (peripheral blood, total bone marrow, HSC) in the recipient mice was almost similar. These results indicate that the GRP78 expression on HSC is reversible, but it seems to be “fixed” into an immature stage and differentiate with lower efficiency toward mature cells after long/strong exposure to Cripto signaling. Based on these findings, we propose that Cripto is a novel factor that maintains HSC in an immature state and may be a potent candidate for expansion of a distinct population of GRP78 expressing HSC. Disclosures: No relevant conflicts of interest to declare.

Novel In Vivo Evidence That Not Only Androgens But Also Pituitary Gonadotropins and Prolactin Directly Stimulate Murine Bone Marrow Stem Cells – Implications For Potential Treatment Strategies In Aplastic Anemias

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2476-2476
Author(s):  
Kasia Mierzejewska ◽  
Ewa Suszynska ◽  
Sylwia Borkowska ◽  
Malwina Suszynska ◽  
Maja Maj ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Sex Hormones ◽  
Peripheral Blood ◽  
Hematopoietic Stem ◽  
Clonogenic Potential

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.

Pluripotent Stem Cell Modeling of Normal and Abnormal Megakaryocyte Development and Platelet Production

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1276-1276
Author(s):  
Brenden W Smith ◽  
Darrell N Kotton ◽  
Gustavo Mostoslavsky ◽  
George J. Murphy
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Pluripotent Stem Cells ◽  
Peripheral Blood ◽  
Patient Specific ◽  
Directed Differentiation ◽  
Platelet Production ◽  
Blood Disorder

Abstract Abstract 1276 Thrombocytopenia is a multi-factorial blood disorder characterized by an abnormally low number of circulating platelets that can have devastating effects upon a wide swath of patients independent of age, race, or socioeconomic group. The two major reasons for thrombocytopenia are increased turnover in immune thrombocytopenia purpura (ITP) and decreased production due to bone marrow failure as a result of chemotherapy, aging, or drugs. Even in ITP, there is some evidence that decreased production may play a role in the etiology of the disease. Thus, patients not making enough platelets are usually treated with platelet transfusions, which carry risks of allergic reactions, infections, and eventually sensitization to allo-antigens making patients refractory to transfusions. With these facts in mind, there is a clear need for the development of novel, autologous sources of mature platelets, and the ability to produce patient-specific megakaryocytes from pluripotent stem cells would have a potential therapeutic role. We have developed a novel, excisable reprogramming vector (STEMCCA) capable of generating ‘clinical grade’ induced Pluripotent Stem Cells (iPSC) free of any residual reprogramming transgenes, and have employed this vector in the derivation of both normal and megakaryocyte disease-specific cell lines. To develop a novel source of platelet precursors for hematopoietic and cell-based therapy studies, we have established conditions for the efficient directed differentiation of these lines into a virtually unlimited supply of functional megakaryocyte-lineage cells that express a constellation of accepted megakaryocyte markers, appropriate Wright-Giemsa stained morphology, expected polyploidy via endoreduplication, and both normal and aberrant platelet production. iPSC-derived megakaryocytes were subsequently tagged with viral vectors expressing fluorescent proteins (for quantification of platelet contribution in peripheral blood) and/or luciferase (for in vivo imaging studies) and administered to mouse models via the retro orbital sinus. Transplanted mice were monitored for the presence of the transferred megakaryocytes and resulting platelets via Ly 5.1/5.2 chimerism as well as for the presence of GFP positive cells using FACS analysis. Peripheral blood from these mice was screened at 1 day post transplantation for chimerism and expression of GFP, and at subsequent 2 day time periods when GFP positive cells were noted in order to track the continued viability or death of the megakaryocyte-lineage cells and resulting platelets. Following these cell transfer experiments, the presence of green platelets in the peripheral blood of these mice indicated that the megakaryocyte-lineage cells produced from the directed differentiation of iPSC are indeed viable in vivo and are capable of the production of platelets. The duration of reconstitution and the functionality of the platelets derived from the iPSC generated megakaryocytes as well as those generated from embryonic stem cell (ESC) controls are currently being assessed by quantifying the labeled platelets over time, and carrying out tests of platelet function in vivo (bleeding time) and in vitro (platelet aggregation studies). Our current work focuses on the hypothesis that an iPSC-based system is capable of producing sufficient numbers of fully functional megakaryocytes to ameliorate thrombocytopenia in vivo. The implications of successfully testing this hypothesis are profound, for they suggest that early megakaryocyte and platelet development can be directly evaluated in vitro and, moreover, that megakaryocyte-lineage cells produced from patient-specific, directly differentiated iPSC lines can become a potent source for transfusion studies and regenerative medicine. Disclosures: No relevant conflicts of interest to declare.

In Vivo Generation of Engraftable Murine Hematopoietic Stem Cells from Induced Pluripotent Stem Cells through Hemogenic Endothelium

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3866-3866
Author(s):  
Masao Tsukada ◽  
Satoshi Yamazaki ◽  
Yasunori Ota ◽  
Hiromitsu Nakauchi
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Stromal Cells ◽  
Pluripotent Stem Cells ◽  
Hematopoietic Cells ◽  
Hematopoietic Stem ◽  
Teratoma Formation

Abstract Introduction Generation of engraftable hematopoietic stem cells (HSCs) from pluripotent stem cells (PSCs) has long been thought an ultimate goal in the field of hematology. Numerous in vitro differentiation protocols, including trans-differentiation and forward programming approaches, have been reported but have so far failed to generate fully functional HSCs. We have previously demonstrated proof-of-concept for the in vivo generation of fully functional HSCs from induced PSCs (iPSCs) through teratoma formation (Suzuki et al., 2013). However, this method is time-consuming (taking over two months), HSCs are generated at low frequencies, and additionally require co-injection on OP9 stromal cells and SCF/TPO cytokines. Here, we present optimization of in vivo HSC generation via teratoma formation for faster, higher-efficiency HSC generation and without co-injection of stromal cells or cytokines. Results First, we screened reported in vitro trans-differentiation and forward programming strategies for their ability to generate HSCs in vivo within the teratoma assay. We tested iPSCs transduced with the following dox-inducible TF overexpression vectors: (1) Gfi1b, cFOS and Gata2 (GFG), which induce hemogenic endothelial-like cells from fibroblast (Pereira et al.,2013); (2) Erg, HoxA9 and Rora (EAR), which induce short-term hematopoietic stem/progenitor cell (HSPC) formation during embryoid body differentiation (Doulatov et,al., 2013); and (3) Foxc1, which is highly expressed the CAR cells, a critical cell type for HSC maintenance (Oomatsu et al.,2014). We injected iPSCs into recipient mice, without co-injection of stromal cells or cytokines, and induced TF expression after teratoma formation by dox administration. After four weeks, GFG-derived teratomas contained large numbers of endothelial-like and epithelial-like cells, and importantly GFG-derived hematopoietic cells could also be detected. EAR-teratomas also generated hematopoietic cells, although at lower frequencies. By contrast, hematopoietic cells were not detected in control teratomas or Foxc1-teratomas. Through use of iPSCs generated from Runx1-EGFP mice (Ng et al. 2010), and CUBIC 3D imaging technology (Susaki et al. 2014), we were further able to demonstrate that GFG-derived hematopoietic cells were generated through a haemogenic endothelium precursor. Next, we assessed whether HSPC-deficient recipient mice would allow greater expansion of teratoma-derived HSCs. This was achieved by inducing c-kit deletion within the hematopoietic compartment of recipient mice (Kimura et al., 2011) and resulted in a ten-fold increase in the peripheral blood frequency of iPSC-derived hematopoietic cells. We further confirmed similar increases in iPSC-derived bone marrow cells, and in vivo HSC expansion, through bone marrow transplantation assays. Finally, we have been able to shorten the HSC generation time in this assay by five weeks through use of transplantable teratomas, rather than iPSCs. Conclusions We have demonstrated that GFG-iPSCs induce HSC generation within teratomas, via a hemogenic endothelium precursor, and that use of HSPC-deficient recipient mice further promotes expansion of teratoma-derived HSCs. These modifications now allow us to generate engraftable HSCs without co-injection of stromal cells or cytokines. Additionally, use of transplantable teratomas reduced HSC generation times as compared with the conventional assay. These findings suggest that our in vivo system provides a promising strategy to generate engraftable HSCs from iPSCs. Disclosures No relevant conflicts of interest to declare.

The Sooner the Better: Rapid Transduction Enhances the Engraftment/Selection of Gene Corrected Fanconi Anemia HSC.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 194-194 ◽  
Author(s):  
Lars U.W. Muller ◽  
Michael Milsom ◽  
Chad E. Harris ◽  
Jeff Bailey ◽  
David A. Williams
Keyword(s):  
Stem Cells ◽  
Gene Therapy ◽  
Bone Marrow ◽  
Stem Cell ◽  
Reporter Gene ◽  
Fanconi Anemia ◽  
Peripheral Blood ◽  
Bone Marrow Cells

Abstract Fanconi anemia (FA) is amenable to genetic correction of hematopoietic stem cells (HSCs). However, as demonstrated in previous clinical gene therapy trials, successful extension of murine studies into human therapies is limited by low numbers of target HSC and poor engraftment of transduced FA HSC (Kelly et al., Mol Ther, 2007). To examine the potential biological consequences/benefits of shortened transduction we used a FA mouse model in which HSC are deficient and prone to excessive loss during in vitro manipulation. We applied a rapid transduction protocol (Mostoslavsky et al., Mol Ther, 2005) utilizing lentiviral vectors and demonstrate that this shortened transduction preserves engraftment of FA HSC to the level of C57BL/6 wt cells. Lin− Sca-1+ c-Kit+ bone marrow cells were isolated from Fanca−/− CD45.2 mice and underwent 4-hr rapid (RT) vs. 96-hr conventional (CT) transduction. An equivalent number of transduced cells were transplanted into lethally irradiated CD45.1 BoyJ mice. Analysis of engraftment chimerism three months post transplantation revealed a significantly higher level of engraftment in animals receiving RT vs. CT cells (90% +/− 14% vs. 26% +/− 31%, respectively, p=&lt;0.01). Rapid transduction also resulted in a significant reduction of engraftment failure (0/36 animals RT vs. 20/36 animals CT). Importantly--emphasizing the FA disease-specific stem cell phenotype, RT vs. CT of C57BL/6 wt cells was associated with no significant difference in engraftment of these cells (93% +/− 1.2% RT vs. 84 +/− 19% CT, p=0.33). Analysis of peripheral blood cells expressing the proviral enhanced green fluorescent protein (eGFP) reporter gene revealed a normal distribution of B-lymphocytes (B220), T-lymphocytes (CD3 epsilon), and granulocytes (MAC-1), indicating multi-lineage engraftment of gene modified cells. In spite of this engraftment advantage, transduction efficiency was low (&lt;30%) using RT. The 6-benzylguanine (6-BG) resistant P140K mutant of O6-methylguanine DNA methyltransferase (MGMTP140K) confers a selective advantage to tranduced HSC treated with alkylating drugs. Following RT with a MGMTP140K/ eGFP expressing lentivirus, 5/6 mice treated with 6-BG and the alkylating drug temozolomide showed a significant rise in the percentage of GFP reporter gene expression in peripheral blood. We extended this approach to the FA model by generating a tri-cistronic lentiviral vector expressing the FANCA cDNA, MGMTP140K, and eGFP. Despite modest in vivo gene marking with this vector, up to 37-fold selection (85% GFP-positive cells) was achieved following exposure of bone marrow of transplant recipients to 6-BG and the alkylating drug temozolomide in vitro. Concurrently, phenotypic correction of mitomycin C hypersensitivity of transduced Fanca−/− bone marrow cells was observed. These data suggest that RT improves stem cell engrafting capacity of FA stem cells in a relevant animal model of stem cell gene therapy. The combination of RT and in vivo selection may allow more successful reconstitution of the lympho-hematopoietic system in gene therapy applications.

Isolation and Synthesis of a Hemoregulatory Peptide

1982 ◽  
Vol 37 (11-12) ◽  
pp. 1297-1300 ◽  
Author(s):  
Walter R. Paukovits ◽  
Ole D. Laerum
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Peripheral Blood ◽  
Pure Form ◽  
Structural Investigations ◽  
Human Leukocytes ◽  
Hemopoietic System

Abstract A peptide was isolated in pure form from human leukocytes which strongly inhibits the proliferation of immature meyloid cells in vitro (committed stem cells). Structural investigations yielded pGlu-Asp or Glu-Asp or Glu-Cys-Lys-OH as the probable sequence of this peptide. The Glu2,Asp3-analog, prepared synthetically, displayed similar activities and when applied in vivo showed effects on the hemopoietic system ranging from an inhibition of pluripotent and committed stem cells to variations in the bone marrow proliferation and alterations in peripheral blood counts.

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