Ex-Vivo Expansion of Multipotent CD133+ Stem Cells with VEGF, FLT3l and SCGF.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4147-4147
Author(s):  
Sonja Loges ◽  
Martin Butzal ◽  
Uta Fischer ◽  
Ursula M. Gehling ◽  
Dieter K. Hossfeld ◽  
...  
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Stem Cell ◽  
Culture System ◽  
Ex Vivo ◽  
Ex Vivo Expansion ◽  
Facs Analysis ◽  
Hematopoietic Stem ◽  
Large Numbers

Abstract The rare CD133+ stem cell population contains both hematopoietic and endothelial progenitors. Successful ex-vivo expansion of this multipotent population would therefore be of great benefit in many clinical settings including stem cell transplantation and gene therapy. We developed a cell culture system containing the recombinant human cytokines vascular endothelial growth factor (VEGF), FLT3 ligand (FLT3L) and stem cell growth factor (SCGF) for ex-vivo expansion of purified human CD133+ stem cells obtained from leukapheresis products from patients pre-treated with G-CSF. FACS analysis, colony assays and NOD-SCID transplantation studies were performed to monitor stem cell and endothelial phenotype in-vitro and in-vivo. Cultivation with VEGF, FLT3L and SCGF induced a mean 2200-fold increase of total cell counts in 5 weeks. FACS analysis revealed persistence of 6–15% CD133+ stem cells indicating proliferation and survival of primitive hematopoietic stem cells. 5–6% of the proliferating cells expressed the endothelial markers CD144 (VE-Cadherin) and von-Willebrand factor (vWF). Ex-vivo expanded stem cells could be differentiated into adherent endothelial cells after withdrawal of SCGF and FLT3L allowing generation of large numbers of endothelial cells. Colony-assays showed an increase of hematopoietic and endothelial colonies after 5 weeks of ex-vivo expansion indicating simultaneous proliferation of hematopoietic and endothelial precursors under the established culture conditions (CFU-E 60-fold, CFU-GEMM 48-fold, CFU-GM 59-fold, CFU-G 99-fold, CFU-M 1356-fold and CFU-EC 1843-fold). To assess in-vivo functionality, hematopoietic stem cells expanded ex-vivo for 7, 14, 21 and 32 days were transplanted into sublethally irradiated NOD-SCID mice. For each expansion period, the mean percentage of anti-human CD45 positive bone marrow cells 3 months post-transplantation was 11, 3, 3 and 1%, respectively. Human CD45+ cells for each set of experiments contained a mean of 15, 26, 8 and 32% T-cells (CD3+), 9, 0, 7 and 21% B-cells (CD19+), 24, 2, 2 and 11% monocytes (CD14+), 21, 3, 1 and 12% granulocytes (CD33+) and 19, 37, 44 and 24% stem cells (CD34+) (d7 (n=5), d14 (n=4), d21 (n=7) and d32 (n=6) respectively). Our experiments showed multilineage engraftment of human stem cells expanded for more than 4 weeks ex-vivo. Therefore our culture system provides a tool to generate large numbers of human stem and endothelial cells for clinical purposes.

Recombinant DEK Enhances Ex Vivo expansion of Human Cord Blood and Mouse Bone Marrow Hematopoietic Stem Cells in a CXCR2- and Hspg-Dependent Manner

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 779-779
Author(s):  
Maegan L. Capitano ◽  
Nirit Mor-Vaknin ◽  
Maureen Legendre ◽  
Scott Cooper ◽  
David Markovitz ◽  
...  
Keyword(s):  
Stem Cells ◽  
Colony Formation ◽  
Ex Vivo ◽  
Fold Increase ◽  
Inhibitory Effect ◽  
Ex Vivo Expansion ◽  
Hematopoietic Stem ◽  
Inhibitory Function

Abstract DEK is a nuclear DNA-binding protein that has been implicated in the regulation of transcription, chromatin remodeling, and mRNA processing. Endogenous DEK regulates hematopoiesis, as BM from DEK-/- mice manifest increased hematopoietic progenitor cell (HPC) numbers and cycling status and decreased long-term and secondary hematopoietic stem cell (HSC) engrafting capability (Broxmeyer et al., 2012, Stem Cells Dev., 21: 1449; 2013, Stem Cells, 31: 1447). Moreover, recombinant mouse (rm) DEK inhibits HPC colony formation in vitro. We now show that rmDEK is myelosuppressive in vitro in an S-phase specific manner and reversibly decreases numbers (~2 fold) and cycling status of CFU-GM, BFU-E, and CFU-GEMM in vivo, with DEK-/- mice being more sensitive than control mice to this suppression. In contrast, in vivo administration of rmDEK to wild type and DEK-/- mice enhanced numbers of phenotypic LT-HSC. This suggests that DEK may enhance HSC numbers by blocking production of HPCs. We thus assessed effects of DEK on ex vivo expansion of human CD34+ cord blood (CB) and mouse Lin- BM cells stimulated with SCF, Flt3 ligand, and TPO. DEK significantly enhanced ex vivo expansion of rigorously-defined HSC by ~3 fold both on day 4 (~15 fold increase from day 0) and 7 (~29 fold increase from day 0) when compared to cells expanded without DEK. Expanding HSC with DEK also resulted in a decrease in the percentage of apoptotic HSC. Further studies were done to better define how DEK works on HSC and HPC. As extracellular DEK can bind to heparan sulfate proteoglycans (HSPG), become internalized, and then remodel chromatin in non-hematopoietic cells in vitro (Kappes et al., 2011, Genes Dev., 673; Saha et al., 2013, PNAS, 110: 6847), we assessed effects of DEK on the heterochromatin marker H3K9He3 in the nucleus of purified mouse lineage negative, Sca-1 positive, c-Kit positive (LSK) BM cells by imaging flow cytometry. DEK enhanced the presence of H3K9Me3 in the nucleus of DEK-/- LSK cells, indicating that rmDEK can be internalized by LSK cells and mediate heterochromatin formation. We also investigated whether inhibiting DEK's ability to bind to HSPG would block the inhibitory function of DEK in HPC. Blocking the synthesis of, the surface expression of, and the binding capability of HSPG blocked the inhibitory effect of DEK on colony formation. Blocking the ability of DEK to bind to HSPG also blocks the expansion of HSC in ex vivo expansion assays, suggesting that DEK mediates its function in both HSC and HPC by binding to HSPG but with opposing effects. To further evaluate the biological role of rmDEK, we utilized single-stranded anti-DEK aptamers that inactivate its function. These aptamers, but not their control, neutralized the inhibitory effect of rmDEK on HPC colony formation. Moreover, treating BM cells in vitro with truncated rmDEK created by incubating DEK with the enzyme DPP4 (DEK has targeted truncation sites for DPP4) eliminated the inhibitory effects of DEK, suggesting that DEK must be in its full- length form in order to perform its function. Upon finding that DEK has a Glu-Leu-Arg (ELR) motif, similar to that of CXC chemokines such as IL-8, and as DEK is a chemoattractant for mature white blood cells, we hypothesized that DEK may manifest at least some of its actions through CXCR2, the receptor known to bind and mediate the actions of IL-8 and MIP-2. In order to examine if this is indeed the case, we first confirmed expression of CXCR2 on the surface of HSC and HPC and then determined if neutralizing CXCR2 could block DEK's inhibitory function in HPC. BM treated in vitro with rmDEK, rhIL-8, or rmMIP-2 inhibited colony formation; pretreating BM with neutralizing CXCR2 antibodies blocked the inhibitory effect of these proteins. DEK inhibition of CFU-GM colony formation is dependent on Gai-protein-coupled receptor signaling as determined through the use of pertussis toxin, which is a mechanism unique to DEK, as we have previously reported that IL-8 and MIP-1a are insensitive to the inhibitory effects of pertussis toxin. Blocking the ability of DEK to bind to CXCR2 also inhibited the expansion of HSC in an ex vivo expansion assay. This suggests that DEK binds to CXCR2, HSPG or both to mediate its function on HPC and HSC, enhancing HSC but decreasing HPC numbers. Therefore, DEK may be a crucial regulatory determinant of HSC/HPC function and fate decision that is utilized to enhance ex vivo expansion of HSC. Disclosures No relevant conflicts of interest to declare.

A secreted and LIF-mediated stromal cell–derived activity that promotes ex vivo expansion of human hematopoietic stem cells

Blood ◽  
2000 ◽  
Vol 95 (6) ◽  
pp. 1957-1966 ◽  
Author(s):  
Chu-Chih Shih ◽  
Mickey C.-T. Hu ◽  
Jun Hu ◽  
Yehua Weng ◽  
Paul J. Yazaki ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Stromal Cells ◽  
Cell Expansion ◽  
Culture System ◽  
Stromal Cell ◽  
Ex Vivo ◽  
Hematopoietic Stem ◽  
Stem Cell Expansion

Abstract The development of culture systems that facilitate ex vivo maintenance and expansion of transplantable hematopoietic stem cells (HSCs) is vital to stem cell research. Establishment of such culture systems will have significant impact on ex vivo manipulation and expansion of transplantable stem cells in clinical applications such as gene therapy, tumor cell purging, and stem cell transplantation. We have recently developed a stromal-based culture system that facilitates ex vivo expansion of transplantable human HSCs. In this stromal-based culture system, 2 major contributors to the ex vivo stem cell expansion are the addition of leukemia inhibitory factor (LIF) and the AC6.21 stromal cells. Because the action of LIF is indirect and mediated by stromal cells, we hypothesized that LIF binds to the LIF receptor on AC6.21 stromal cells, leading to up-regulated production of stem cell expansion promoting factor (SCEPF) and/or down-regulated production of stem cell expansion inhibitory factor (SCEIF). Here we demonstrate a secreted SCEPF activity in the conditioned media of LIF-treated AC6.21 stromal cell cultures (SCM-LIF). The magnitude of ex vivo stem cell expansion depends on the concentration of the secreted SCEPF activity in the SCM-LIF. Furthermore, we have ruled out the contribution of 6 known early-acting cytokines, including interleukin-3, interleukin-6, granulocyte macrophage colony-stimulating factor, stem cell factor, flt3 ligand, and thrombopoietin, to this SCEPF activity. Although further studies are required to characterize this secreted SCEPF activity and to determine whether this secreted SCEPF activity is mediated by a single factor or by multiple growth factors, our results demonstrate that stromal cells are not required for this secreted SCEPF activity to facilitate ex vivo stem cell expansion.

Novel Method to Study Mouse Bone Marrow Endothelial Cells in Vivo and in Vitro

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 617-617 ◽  
Author(s):  
Yuxin Feng ◽  
Ming Liu ◽  
Fukun Guo ◽  
Wei Liu ◽  
Leesa Sampson ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Endothelial Cells ◽  
Culture System ◽  
Assay Method ◽  
Mouse Bone Marrow ◽  
Hematopoietic Stem ◽  
Egfp Reporter

Abstract Abstract 617 Self-renewal, differentiation, and proliferation of hematopoietic stem cells (HSCs) and leukemia stem cells (LSCs) are maintained in a complex microenvironment of the adult bone marrow (BM). BM endothelial cells (ECs) have been proposed to be a key component of HSC and LSC niche. However, in contrast to the well-developed culture system of human ECs, current work of murine BM endothelial cells is hindered by a lack of mouse bone marrow endothelial cell primary culture and suitable assay methods to clearly define murine BMEC functionality in vivo and in vitro, which limits genetic and mechanistic studies by using mouse models. To establish an in vivo approach to study the EC function in adult mice, a strain of Tie2-CreER transgenic mice was generated to allow conditional and inducible manipulation of BMECs by Cre recombinase expression under the Tie2 promoter. In vivo lineage tracing was achieved in a Tie2-CreER/TD-tomato or -EGFP reporter mouse strain. Upon a four day Tamoxifen injection regimen, TD-tomato or EGFP reporter was readily visualized in bone marrow vasculature that colocalizes with CD31+ ECs as determined by immunostaining. FACS analysis of Tie2-CreER/EGFP reporter mice showed that the EGFP+ cells in the BM were exclusively in the CD45- VEGFR2+ and CD31+ cell fraction, with no EGFP+ cells being detectable in the CD45+ hematopoietic lineages or osteoblast/stroma cell fractions, suggesting that the Tie2-driven CreER expression is limited to the endothelial lineage in the adult BM. Next, we developed an in vitro method to culture and assay the mouse BMECs functionally. An in vitro selection process allowed us to establish a primary BM cell culture condition that permitted functional expansion and maintenance of mouse BMECs in long-term tissue culture, yielding homogenous CD45- cells expressing endothelial markers CD31, CD34 and VEGFR2. These cells formed capillary-like structures in 2-demensional and 3-demensional tubes/capillaries, and showed TD-tomato reporter color when derived from the Tamoxifen induced Tie2-CreER/TD-tomato mouse BM. They showed expected adhesion and migration activities and morphology of ECs. Lineage chasing assays using isolated CD45+ and CD45- BM cells from the Tie2-CreER/Td-tomato mice demonstrated that the BMECs in our culture system, bearing the Tie2-promoter driven TD-tomato color and CD31+ marker, were exclusively derived from CD45- non-hematopoietic lineage. Taken together, we have established a faithful assay method for studying murine BM EC functions in vivo and in vitro, allowing the tracking and genetic manipulation of adult BM ECs in mice and in culture. The method can be useful for delineating molecular and cellular mechanisms of BMEC regulation and EC-mediated BM niche function, and may have value in testing anti-angiogenic activities of anticancer drugs in animal models. Disclosures: No relevant conflicts of interest to declare.

Expansion of Cord Blood Stem Cells Mediated by Epigenetic Mechanisms Remain Permissive to External Environmental Cues

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3868-3868
Author(s):  
Hiroto Araki ◽  
Kazumi Yoshinaga ◽  
Sudhakar Baluchamy ◽  
Benjamin Petro ◽  
Donald Lavelle ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cord Blood ◽  
Ex Vivo ◽  
Trichostatin A ◽  
Ex Vivo Expansion ◽  
Division Rate ◽  
Hematopoietic Stem ◽  
Immunodeficient Mice ◽  
Cytokine Combination

Abstract Widespread use of ex vivo expanded hematopoietic stem cells (HSC) has been largely limited by the lack of proper understanding of factors regulating symmetric self-renewing HSC divisions. We have previously reported that the addition of a hypomethylating agent, 5-aza-2′-deoxyctidine (5azaD) and a histone deacetylase inhibitor, trichostatin A (TSA) in the culture is capable of expanding cord blood (CB) HSC as detected by in vivo SCID repopulating cells (SRC) assay in immunodeficient mice. The increase in SRC during ex vivo expansion culture was associated with greater transcript and protein products of genes implicated in HSC self-renewal (Araki et al. Blood 2007). In order to determine whether variation of exogenous cytokine cocktails added in the culture influences the degree of expansion of HSC treated with 5azaD/TSA, we have cultured CD34+ CB cells in the presence of various cytokine combinations. Interestingly, despite treatment of CB cells with 5azaD/TSA the expansion of stem/progenitor cells varied greatly, depending on the combinations of cytokines used in the culture, ranging between 5 to 12 fold differance. The cytokine combination containing stem cell factor (SCF), Flt3-ligand (FL) and thrombopoietin (TPO) was found to promote maximal expansion of primitive CD34+CD90+ cells following treatment with 5azaD/TSA in comparison to other cytokine combinations used (GM-CSF+SCF+IL-3+IL-6+EPO, SCF+FL+TPO+IL-3, SCF+FL+TPO+IL-6, SCF+FL+TPO+IL-3+IL-6, SCF+IL-3+IL-6). Our results also indicate the importance of sequential addition of 5azaD followed by TSA for the net expansion of HSC. Reversal of the sequence of addition of 5azaD and TSA (TSA followed by 5azaD) resulted in almost complete abrogation of the expansion of primitive CD34+CD90+ cells, and this loss of expansion corresponded with decreased acetylation of histone H4. We have further demonstrated that despite pre-treatment with sequential 5azaD/TSA, various cytokine cocktails in the culture can affect the rate of CD34+CD90+ cell divisions which influences both in vitro clonogenic potential and in vivo SRC potential. The higher in vivo hematopoietic engraftment potential of 5azaD/TSA treated cells in the presence of the optimal cytokine combination (SCF+FL+TPO) is likely due to expansion of a relatively primitive HSC population in the culture which divides slower than the cells expanded in the presence of other cytokine combinations (i.e. SCF+FL+TPO+IL-3+IL-6). Further studies will be needed to understand the molecular mechanism of the loss of functional potential depending on culture conditions. Thus far, in a transwell culture system, CD34+CD90+ cells that have been expanded with 5azaD/TSA show greater migration potential towards stroma derived factor (SDF-1) than CD34+CD90+ cells that have been expanded in cytokines alone without 5azaD/TSA treatment. Most importantly the fraction of migrating cells present in the 5azaD/TSA treated expanded culture was comparable to unmanipulated primary CB CD34+ cells, a likely factor contributing to better engraftment in an immunodeficient mouse model. Our current studies indicate that HSC remain responsive to external humoral influences even after treatment with chromatin modifying agents. The relatively slower cell division rate of CB cells in the presence of 5azaD/TSA might be a critical determinant for the retention of HSC functional capability following ex vivo expansion.

Low Dose IGFBP1, IGFBP2 and ANGPTL3 Coordinately Stimulate Ex Vivo Expansion of Human Umbilical Cord Blood (UCB) Hematopoietic Stem Cells (HSCs).

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1546-1546
Author(s):  
Xiubo Fan ◽  
Pak Yan Chu ◽  
Florence Gay ◽  
Sudipto Bari ◽  
Justina Ang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cord Blood ◽  
Umbilical Cord Blood ◽  
Culture System ◽  
Low Dose ◽  
Ex Vivo ◽  
Ex Vivo Expansion ◽  
Optimal Dosage ◽  
Hematopoietic Stem ◽  
Cytokine Combination

Abstract Abstract 1546 Ex vivo expansion of umbilical cord blood (UCB) hematopoietic stem cells (HSCs) may overcome the obstacle of low cell dose for UCB transplantation in adults. Insulin like growth factors (IGFs), IGF binding proteins (IGFBPs) and angiopoietin like proteins (ANGPTLs) can further enhance the ex vivo expansion of HSCs when used with a standard cytokine cocktail of stem cell factor (SCF), thrombopoietin (TPO) and FLT3-ligand (FL). Current doses of IGFBPs and ANGPTLs are in the range of 100∼500ng/ml, but these concentrations may not be optimal and high concentrations could be costly for clinical use. In order to determine the optimal dosage of IGFs, IGFBPs and ANGPTLs, 4×105cells/mL of cryopreserved clinical UCB was inoculated in serum-free Stemspan® medium supplied with standard basal cytokine combination of 100ng/ml SCF, 50ng/ml FL and 100ng/ml TPO on an MSCs stromal layer and with individually varied doses of IGFBP1, IGFBP2, IGF2 and ANGPTL3 in the range of 0∼200ng/ml. In order to determine optimal cytokine combination, complete permutation was carried out after establishing the optimal dosage of each cytokine. On day 7, the same amount of Stemspan® medium with the indicated cytokine combination was replenished to the culture system. Cord blood cells were harvested after 12 days ex vivo culture and assayed for total cell count, cell surface phenotype (viability determined by CD45/AnnV/7AAD staining, primitive progenitor determined by CD45/CD34/CD38/CD90 staining) and functional studies (Colony-forming unit-granulocyte and macrophage (CFU-GM) was determined by methylcellulose colony culture). Paradoxically, the highest expansion of CD34+CD38-CD90+ primitive progenitor was at a low dose of 20ng/ml for IGFBP1, IGFBP2, IGF2 and ANGPTL3 when concentrations of 0, 20, 50, 100 and 200 ng/ml were studied (Fig. 1A). Based on this results the cytokine dosage range was narrowed down to 0∼50ng/ml and experiments (Fig. 1B) showed that the optimal cytokines dosages were 20ng/ml of IGFBP2 and ANGPTL3, 15ng/ml IGFBP1 and 10ng/ml IGF2, which could stimulate 13.0±1.1 fold, 13.3±2.4 fold, 11.0±0.8 fold and 14.3±2.1 fold expansion of CD34+CD38-CD90+ primitive progenitor compared to 6.8±0.2 fold with standard cytokine control (p =0.01). Studying multiple permutations, combination “ABD” comprising 15ng/ml IGFBP1, 20ng/ml IGFBP2 and 20ng/ml ANGPTL3 had the highest expansion of CD34+CD38-CD90+ primitive progenitor (27.7±2.2 fold compared to 8.5±1.1 fold with standard cytokines, p =0.01), was found to be superior to all other combinations, including combinations “A”, “B”, “BC”, “BD”, “CD” and “ABCD”, which could stimulate over 2 fold expansion of primitive progenitor compare to control (Figure 1C). Interestingly, despite expansion of primitive CD34+CD38-CD90+ cells, there was no further enhancement of the expansion of total cells and general progenitors compare to control (data not shown), suggesting that the cyokine cocktail enhanced only the earliest progenitors. In conclusion, IGFBP1, IGFBP2, IGF2 and ANGPTL3 can stimulate the expansion of CD34+CD38-CD90+ primitive progenitor at low dosage, and the optimal combination comprises IGFBP1, IGFBP2 and ANGPTL3. Further in vivo experimentation is in progress to verify the effect of our optimized cytokine combination culture system on ex vivo expansion of cryopreserved unselected clinical UCB HSCs. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Development of Human Mast Cells from Hematopoietic Stem Cells within a 3D Collagen Matrix: Effect of Stem Cell Media on Mast Cell Generation

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Tahereh Derakhshan ◽  
Rudra Bhowmick ◽  
Jerry W. Ritchey ◽  
Heather Gappa-Fahlenkamp
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Mast Cells ◽  
Hematopoietic Stem Cells ◽  
Collagen Matrix ◽  
Hematopoietic Stem ◽  
Large Numbers ◽  
3D Matrix ◽  
3D Collagen

Mast cells (MCs) arise from hematopoietic stem cells (HSCs) that mature within vascularized tissues. Fibroblasts and endothelial cells (ECs) play a role in the maturation of HSCs in the tissues. Due to difficulties in isolating MCs from tissues, large numbers of committed MC precursors can be generated in 2D culture systems with the use of differentiation factors. Since MCs are tissue-resident cells, the development of a 3D tissue-engineered model with ancillary cells that more closely mimics the 3Din vivomicroenvironment has greater relevance for MC studies. The goals of this study were to show that MCs can be derived from HSCs within a 3D matrix and to determine a media to support MCs, fibroblasts, and ECs. The results show that HSCs within a collagen matrix cultured in StemSpan media with serum added at the last week yielded a greater number of c-kit+cells and a greater amount of histamine granules compared to other media tested. Media supplemented with serum were necessary for EC survival, while fibroblasts survived irrespective of serum with higher cell yields in StemSpan. This work demonstrates the development of functional MCs within a 3D collagen matrix using a stem cell media that supports fibroblast and ECs.

Recombinant TAT-HOXB4 Protein Promotes Ex Vivo Expansion of Primitive Human Hematopoietic Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2855-2855
Author(s):  
Gorazd Krosl ◽  
Marie-Pier Giard ◽  
Jana Krosl ◽  
R. Keith Humphries ◽  
Guy Sauvageau ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Ex Vivo Expansion ◽  
Cell Populations ◽  
Mouse Bone Marrow ◽  
Hematopoietic Stem

Abstract The clinical application of therapeutic protocols depending on hematopoietic stem cell (HSC) transplantation for long term reconstitution with donor-derived HSCs, particularly in patients previously exposed to intensive radiation or chemo-therapy, or when grafts are purged of infiltrating malignant or alloreactive T cells, can be severely hampered by limited numbers of HSCs in the graft. In mouse bone marrow transplantation models, engineered overexpression of HOXB4 has been one of the most potent stimulator of HSC expansion identified to date. The simple addition of soluble recombinant TAT-HOXB4 protein was also recently reported to enable rapid in vitro expansion of mouse HSCs that retain their in vivo proliferation and differentiation capacity. To test the feasibility of using TAT-HOXB4 as a stimulator of human HSC expansion, we performed a series of experiments using CD34+ populations isolated from healthy volunteers. The CD34+ cell populations were cultured in X-Vivo medium supplemented with Stem Cell Factor (300 ng/mL) and G-CSF (50 ng/mL) in the presence or absence of TAT-HOXB4 protein (50 nmol/L) for 4 days. In response to TAT-HOXB4, total numbers of mononuclear cells demonstrated a modest but distinct 2-fold increase compared to controls. TAT-HOXB4 treatment had the largest proliferation enhancing effect on more primitive cell populations such as CFU-GEMM, BFU-E and BFU-Meg, whose numbers increased 26.5 ± 1.4 fold (mean±S.D.), 2.2 ± 0.7 fold and 2.1 ± 0.2 fold, respectively, over their input values, and 19.1 ± 1.3 fold, 2.7 ± 0.7 and 31 ± 3.4 fold, respectively, compared to growth factor only controls. In response to TAT-HOXB4, the total numbers of CD34+CD38-Lin- cells increased 2.1 ± 0.7 fold above their starting numbers compared to a 1.5 ± 0.5 fold loss of this population in control cultures. HSC numbers were enumerated at the beginning, and after a 4-day TAT-HOXB4 treatment period using a NOD/SCID repopulation assay. In response to 50 nM TAT-HOXB4, NOD/SCID repopulating cell (SRC) numbers increased ~2-fold over their input values, compared to a 9-fold loss in control cultures without TAT-HOXB4. These results show that recombinant TAT-HOXB4 protein has the capacity to rapidly induce ex vivo expansion of primitive human bone marrow populations, and suggest that optimization of treatment conditions will rapidly lead to clinically useful expansion of human HSCs.

Towards the Development of a Closed, Nanofiber-Based Culture System for Clinical Expansion of Cord Blood-Derived CD34+ Cells

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4411-4411
Author(s):  
Stephen E Fischer ◽  
Yiwei Ma ◽  
Caitlin Smith ◽  
Anirudhasingh Sodha ◽  
Yukang Zhao
Keyword(s):  
Bone Marrow ◽  
Tissue Culture ◽  
Stem Cell ◽  
Cord Blood ◽  
Culture System ◽  
Ex Vivo ◽  
Ex Vivo Expansion ◽  
Cell Phenotype ◽  
Hematopoietic Stem ◽  
Cd34 Cells

Abstract Abstract 4411 Interest in ex vivo hematopoietic stem and progenitor cell (HSPC) expansion has increased in recent years due to the growing importance of these cells in the treatment of a variety of both malignant and non-malignant diseases. Ex vivo expansion of cord blood-derived cells has been particularly investigated because cord is a valuable and readily available source of HSPCs, yet contains limited numbers of cells in each unit. Despite these efforts, most attempts to use expanded cord blood HSPCs in the clinic have been unsuccessful due to the generation of insufficient numbers of cells with the appropriate phenotype and the ability to function in vivo. In many ex vivo culture systems, HSPCs are cultured as a suspension cells and cultured in the presence of various media additives that act to enhance cell proliferation while reducing differentiation. An often-overlooked factor influencing fate decisions is the interaction of HSPCs with a substrate. In the natural bone marrow microenvironment, HSPCs maintain close contact with a complex network of stromal cells and extracellular matrix, likely indicating that cell-cell and cell-matrix interactions play an important role in maintaining their stem cell phenotype. With the goal of mimicking the bone marrow stem cell niche, Arteriocyte, Inc. has developed a 3-D nanofiber-based cell culture substrate (NANEX™). The functionalized NANEX™ substrate is designed to provide topographical and substrate-immobilized biochemical cues that act in synergy with media additives to enhance HSPC proliferation while minimizing differentiation. Here, we present our recent work towards developing a closed, NANEX™-based platform for large-scale clinical expansions of cord blood-derived CD34+ cells. We demonstrate that NANEX™ expands CD34+ cells from cord an average of more than 150-fold in 10 day culture, which is at least 2-fold higher than that obtained in standard tissue culture plates. Additionally, we show an approximately 1.5-fold higher proliferation of colony forming cells and a significantly higher engraftment rate in NSG mice for NANEX™-expanded cells compared to cells cultured in tissue culture plates. Furthermore, we demonstrate that the NANEX™ scaffold maintains its HSPC growth promoting characteristics after processing into a closed culture system and offers significant advantages over other culture platforms typically used for HSPC expansions in the clinic (culture bags and T-flasks). Our data indicates that NANEX™ technology provides a robust ex vivo expansion of cord blood HSPCs and, with further development, offers great potential for clinical applications requiring large numbers of functional cells. Disclosures: No relevant conflicts of interest to declare.

Pyrimido-Indole Derivatives Are Novel Agonists of Human Cord Blood Hematopoietic Stem Cell Self-Renewal

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 650-650
Author(s):  
Iman Fares ◽  
Jalila Chagaroui ◽  
Yves Gareau ◽  
Stéphane Gingras ◽  
Nadine Mayotte ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cord Blood ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Ex Vivo Expansion ◽  
Fed Batch ◽  
Self Renewal ◽  
Hematopoietic Stem

Abstract The widespread use of cord blood (CB) unit in transplantation is limited with low number of long-term hematopoietic stem cells (LT-HSCs) and progenitors. Several approaches have been developed to expand HSC ex vivo such as automated and continuous medium delivery (fed-batch), notch delta ligand and SR1 (antagonist of aryl hydrocarbon receptor (AhR)). Concurrent with these studies, we hypothesized that small molecule with potent LT-HSC stimulating activity might be identified and potentiated in fed-batch culture system. Accordingly, we tested a library of more than 5000 small molecules for their in vitro expansion of CD34+CD45RA- cells. Most of the identified hits, except one (UM729) synthesized in our institute, suppress AhR pathway. Structure activity relationship was performed on UM729 to generate a more potent analog named UM171. This optimized molecule was 10-20 times more potent with an effective concentration of 15-20 nM when tested for its ability to expand CD34+CD45RA- cells. When compared to SR1, UM171 delivered in a fed-batch system for 12 and 16 days showed a better expansion of HSC phenotypes and lower apoptotic cell number compared to SR1 or DMSO controls. Also, UM171-expaned cultures showed higher number in multipotent progenitors (CFU-GEMM) and long term initiating cells (LTC-IC) compared to DMSO controls. Further studies showed the UM171 did not affect division rate, and its effect in expanding HSC phenotype was reversible. When combined with SR1, UM171 showed a better suppression of differentiation and led to a higher CFU-GEMM expansion compared to the single treatment of the compounds or DMOS controls. These observations suggest that UM171+SR1 cooperate to enhance ex vivo expansion of progenitor cells and suppress differentiation. To determine the in vivo activity of the expanded CD34+ CB cells, we transplanted fresh (un-manipulated) and 12-day cultured cells in NSG mice and monitored the human hematopoietic reconstitution after 20 and 30 weeks post-transplantation. Frequencies of day0 equivalent LT-HSCs were 13-fold higher in UM171 expanded cultures compared to fresh or fed-batch cultures supplemented with DMSO or SR1. Secondary experiments indicated that UM171 ex vivo treatment did not appear to affect the capability of LT-HSC to expand in primary recipients and hence similarly reconstituted secondary animals for at least 18 more weeks. This suggests that UM171 expands LT-HSC ex vivo without losing their engraftment potential. To further investigate UM171 mechanism of action, RNA- Seq expression profiling was performed. Unlike SR1 or DMSO controls, UM171 treatment was accompanied by a marked suppression of transcripts associated with erythroid and megakaryocytic differentiation and up-regulation of membrane protein transcripts such as EPCR and TEMEM 183a. In summery, UM171 is the first molecule identified so far that enables a robust ex vivo expansion of human CD34+ CB cells that sustain their in vivo activity independent of AhR suppression. Conversely, AhR suppression was limited to expand cells with less durable self-renewal potential. This study could enhance the use of small yet well HLA-matched CB units to become a prioritized source for stem cells transplantation. Disclosures No relevant conflicts of interest to declare.

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