Phenotypic Examination of Side Population (SP) Cells in Highly Enriched Human CD34+ Cells Obtained from Peripheral Blood Progenitor Cells (PBPC) and Bone Marrow.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4140-4140
Author(s):  
Dag Josefsen ◽  
Leiv S. Rusten ◽  
Trond Stokke ◽  
Lise Forfang ◽  
Erlend B. Smeland ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Cell Population ◽  
Peripheral Blood ◽  
Side Population ◽  
Hoechst 33342 ◽  
Hematopoietic Stem ◽  
Immature Cell ◽  
Cd38 Expression ◽  
Cd34 Cells

Abstract CD34+ cells isolated from bone marrow include hematopoietic stem cells (HSC) as well as more lineage committed hematopoietic progenitor cells (HPC), demonstrating that CD34+ cells are a relatively heterogeneous cell population. Highly enriched CD34+ cells isolated from peripheral blood (PBPC) after mobilization shows a more immature profile with less expression of lineage restricted markers indicating that CD34+ cells from PBPC are a more homogenous immature cell population than CD34+ cells obtained from bone marrow. By using Hoechst 33342-dye efflux assay, which identifies a population of immature HPC, termed side population (SP) cells we have examined the phenotypical profile of SP+CD34+ cells obtained from bone marrow and SP+CD34+ cells isolated from PBPC. Highly enriched CD34+ cells were isolated from PBPC obtained from patients with Hodgkin lymphoma, and bone marrow was obtained from healthy volunteer donors by iliac crest aspiration after informed consent. To identify the SP+ cells, enriched CD34+ cells were stained with Hoechst 33342 dye. Using flowcytometric techniques (FACStar+, FACSDiva, Becton Dickinson, San Jose, CA) we were able to visualize the dye efflux in SP+ cells. SP+ cells were functionally confirmed using Verapamil staining. The frequenzy of LTC-IC was markedly increased in SP+CD34+ cells compared to SP−CD34+ cells (n=5), in line with previous reports. The percentage of SP+CD34+ cells varied from 0,4 to 18% of the total CD34+ cell population obtained from PBPC (n= 16), whereas the level of SP+CD34+ cells obtained from bone marrow varied between 4–7% of the total CD34+ cell population (n=4). Expression of lineage committed markers, including CD10, CD15 and CD19 was less then 10% of the whole CD34+ cell population obtained from PBPC, whereas we found a higher level of expression of these markers in CD34+ cells isolated from bone marrow. However, when we examined the SP+CD34+ cells from either PBPC or bone marrow, we observed that the phenotypical profile of these cells were similar with almost no expression of lineage markers. Thus, the more lineage-committed cells in the CD34+ cell population obtained from bone marrow seems to be restricted to the SP−CD34+ cell fraction. Examination of CD90 and CD133 expression revealed a higher level in the SP+ CD34+ cell fractions compared to the SP− fractions. Furthermore, we investigated the level of CD38 expression. Previous studies have demonstrated that lack of CD38 expression in CD34+ cells identifies a more immature cell population. Surprisingly, we observed that 30–40% of SP+CD34+ cells obtained from bone marrow were CD38 negative, whereas the level of SP+CD34+CD38− cells from PBPC was 2–5%, which is similar to the level of CD38− cells in the CD34+ cell population isolated from both PBPC and bone marrow. Currently, we are exploring the frequency of LTC-IC in SP+CD34+CD38− cells from bone marrow, and we are also planning cell sorting of these cells for functional analyses. In conclusion, we find that the level of CD38 negative cells in SP+CD34+ subpopulation of CD34+ bone marrow cells are higher than what observed in SP+CD34+ and SP−CD34+ from PBPC as well as in SP−CD34+ from bone marrow. Our ongoing studies will clarify if these results define SP+CD34+CD38− cells from bone marrow as a source of highly enriched primitive HPC.

Characterisation of Side Population (SP) Cells Obtained from Different Hematopoietic Progenitor/Stem Cell Compartments in Human Bone Marrow and Peripheral Blood.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4170-4170
Author(s):  
Dag Josefsen ◽  
Lise Forfang ◽  
Marianne Dyrhaug ◽  
Gunnar Kvalheim
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Cell Population ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Human Bone ◽  
Human Bone Marrow ◽  
Hematopoietic Stem ◽  
Cell Compartments ◽  
Cd34 Cells

Abstract Side population (SP) cells are characterised by their ability to exclude Hoechst 33342 dye from the cells. Using this method, it has been demonstrated that cells within the SP+ fraction of mononuclear cells from both murine and human hematopoietic systems are enriched for primitive hematopoietic stem- and progenitor cells. Moreover, most of the SP+ cells did not express CD34, indicating the presence of a CD34 negative hematopoietic stem cell population. To explore this further, we have examined SP+ cells obtained from different cell compartments in human bone marrow and peripheral blood. Human bone marrow (BM) was obtained from healthy volunteer donors by iliac crest aspiration after informed consent. Mononuclear cells (MNC) were obtained by Ficoll grade centrifugation. CD34+ cells were then isolated from MNC. Highly enriched CD34+ cells were isolated from PBPC obtained from patients with Hodgkin lymphoma. To identify the SP+ cells, the cells were stained with Hoechst 33342 dye. Using flowcytometric techniques (FACStar+, FACSDiva, Becton Dickinson, San Jose, CA) we were able to visualize the dye efflux in SP+ cells. SP+ cells were functionally confirmed using Verapamil. Phenotypical characterisation of the different cell populations using flow cytometric methods was performed. The level of SP+ cells in BM-MNC was 1,3% (mean, n=3) In line with previous findings, we observed that SP+ cells obtained from BM-MNC lack expression of several lineage committed markers, including CD15 and CD19. Most of the cells were CD34− (mean=2,2%), which was lower than in the main population (MP; mean=5%). The level of CD133 expression was low and similar in both populations. Furthermore we found a higher fraction of CD3+ T-cells in the SP fraction than in the MP fraction (mean: 69% vs 51%). To further investigate the SP+CD34+ cell fraction, we examined CD34+ cells isolated from both human bone marrow and peripheral blood. The percentage of SP+CD34+ cells varied from 0,4 up to 18% of the total CD34+ cell population obtained from PBPC (n= 16), whereas the level of SP+CD34+ cells obtained from bone marrow was 5% of the total CD34+ cell population (n=3). Expression of lineage committed markers, including CD10, CD15 and CD19 was less then 10% of the whole CD34+ cell population obtained from PBPC, whereas we found a higher level of expression of these markers in CD34+ cells isolated from bone marrow. However, when we examined the SP+CD34+ cells from either PBPC or bone marrow, we observed that the phenotypic profile of these cells were similar with almost no expression of lineage markers. The frequency of LTC-IC was markedly increased in SP+MNC, in line with previous findings. In addition we also observed a marked increase in LTC-IC in SP+CD34+ cells compared to SP-CD34+ cells in both BM and PB (BM: 7-fold increase; PB: 3–4 fold). In conclusion, SP cells are present in different hematopoietic progenitor cell populations, including BM-MNC, BM-CD34+ cells and PB-CD34+ cells. In SP+CD34+ cell fractions from both BM and PB we observed an increased expression of stem cell markers like CD90 and CD133, whereas in SP+MNC we found low levels of CD34, CD90 and CD133 expression. However, the LTC-IC frequency was markedly higher in all SP+fractions compared to MP fractions, suggesting that sorting of SP+ cells from different hematopoietic stem- and progenitor cell compartments identify immature hematopoietic cells.

The RNA Editing Enzyme ADAR1 Is Required for Survival of Differentiating Hematopoietic Progenitor Cells in Adult Mice.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1395-1395
Author(s):  
Feng Xu ◽  
Qingde Wang ◽  
Hongmei Shen ◽  
Hui Yu ◽  
Yanxin Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Rna Editing ◽  
Cell Population ◽  
Peripheral Blood ◽  
Hematopoietic Progenitor Cells ◽  
Hematopoietic Progenitor ◽  
Hematopoietic Stem ◽  
Low Level ◽  
Adult Mice

Abstract Adenosine Deaminases Acting on RNA (ADAR) are RNA-editing enzymes converting adenosine residues into inosine (A-to-I) in many double-stranded RNA substrates including coding and non-coding sequences as well as microRNAs. Disruption of the ADAR1 gene in mice results in fetal liver, but not yolk sac, defective erythropoiesis and death at E11.5 (Wang Q et al, Science 2000). Subsequently, a conditional knockout mouse model confirmed these findings and showed massively increased cell death in the affected organs (Wang Q et al, JBC 2004). However, the actual impact of ADAR1 absence on definitive or adult hematopoiesis has not been examined. To define the role of ADAR1 in adult hematopoiesis, we first examined the expression of ADAR1 in different hematopoietic stem/progenitor cell subsets isolated from bone marrow by real-time RT-PCR. ARAR1 was present in hematopoietic stem cells (HSCs) at relatively low level and increased in hematopoietic progenitor cells (HPCs). A series of functional hematopoietic assays were then undertaken. A conditional deletion of ADAR1 was achieved by transducing Lin− or Lin−cKit+ bone marrow cells from ADAR1-lox/lox mice with a MSCV retroviral vector co-expressing Cre and GFP. PCR analysis confirmed the complete deletion of ADAR1 in the transduced cells within 72 hours after the transduction. This system allowed us to evaluate the acute effect of ADAR1 deletion in a specific hematopoietic cell population. Following 4 days of in vitro culture after transduction, the absolute number of Lin− Sca1+ cells in the Cre transduced group was similar to the input number; however the differentiating Lin+ cells significantly decreased whereas both the Lin−Sca1+ and Lin+ cells in the vector (MSCV carrying GFP alone) transduced group increased during culture. Moreover, the colony forming cell (CFC) assay showed much fewer and smaller colonies that contained dead cells from the gene deleted group as compared to those from the control group (p<0.001). The TUNEL assay showed a dramatic increase of apoptosis in the Lin+ population but not in the Lin− cells. Given the mixed genetic background of the ADAR1-lox/lox mice, repopulation of the transduced hematopoietic cells in vivo was examined in immunodeficient mice. Sublethally irradiated (3.5 Gy) NOD/SCID-γcnull recipient were transplanted with either 1.5 × 105 Cre or vector transduced Lin− ADAR1-lox/lox cells. Multi-lineage engraftment in peripheral blood was monitored monthly. While the vector transduced cells were able to constitute more than 90% in multiple lineages of the peripheral blood at 1 to 3 months, Cre-transduced cells were virtually undetectable at all the time points (n=9 to 13, p<0.001). A similar result was found in the hematopoietic organs, including the bone marrow, spleen and thymus. Interestingly, however, the Lin−Sca1+cKit+ cell population was preserved in the Cre transduced group despite the very low level of total donor-derived cells in the bone marrow (n=6 to 7, p<0.01). Consistently, the single cell culture experiment demonstrated that there was no significant difference between ADAR−/− and wild-type HSCs in terms of survival and division during the first 3 days of culture. Taken together, our current study demonstrates nearly absolute requirement of ADAR1 for hematopoietic repopulation in adult mice and it is also suggested that ADAR1 has a preferential effect on the survival of differentiating progenitor cells over more primitive cells.

scholarly journals Low Dose Umbilical Cord Blood Transplant Results in Skewed Immune Cell Composition Which May Impact Immune Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5672-5672
Author(s):  
Chi Hua Sarah Lin ◽  
Beth Shaz ◽  
Rona Singer Weinberg
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
T Cell ◽  
Cell Population ◽  
Peripheral Blood ◽  
Low Dose ◽  
High Dose ◽  
Hematopoietic Stem ◽  
Nsg Mice ◽  
Cd34 Cells

Abstract Introduction Reconstitution of donor-derived immune system after allogeneic hematopoietic stem cell transplantation (HSCT) is essential for recovery and long-term survival. Despite routine use of human umbilical cord blood (hUCB) as a stem cell source for allogeneic HSCT, much remains unknown regarding the kinetics of immune recovery and correlation with different transplant cell dosages. To study the hUCB repopulating potential, different hUCB CD34+ cell dosages were transplanted into immune deficient NSG mice; hematopoietic cells were then collected and engraftment was analyzed. Methods NOD/SCID/IL-2Rγnull recipient (NSG) mice (Jackson Laboratories, Bar Harbor, ME) were kept in pathogen-free facilities. CD34+ cells were isolated from a pool of six hUCB donors using a CD34+ microbead kit (Miltenyi Biotec). Each sublethal irradiated (220 or 300 cGy) 8 week old female NSG mice received either low dose (15x103, N=15) or high dose (75x103, N=15) CD34+ cells transplanted intravenously via retro-orbital route. Animal experiments were performed in accordance with Institutional Animal Care and Use Committee guidelines. Statistical analysis was performed with Prism software (GraphPad Software, Inc) and Excel. Data are presented as mean ± standard error of the mean (SEM). Results To determine the effects of hUCB CD34+ cell dosages on the rate of engraftment, NSG mice were transplanted with low doseor high dose CD34+ cells. The transplanted CD34+ cell dosages were comparable to clinical dosages based on body weight (Mavroudis et al. 1996). The engrafted cells were analyzed for expression of surface markers that define human hematopoietic cells. During the follow up period of up to 18 weeks, the high dose infused group had increased hUCB engraftment compared with the low dose infused group in peripheral blood (Fig 1A), bone marrow (Fig 1B & 1C) and spleen (Fig 1D), which is consistent with reported clinical observations that infused cell dosage is inversely correlated with time to engraftment (Migliaccio et al. 2000 Blood). Interestingly, we observed different lymphoid subset frequencies between low and high dose infused groups at the post-engraftment stage (18 weeks post transplantation) (data not shown). To investigate different lymphoid subset engraftment frequencies in low and high dose hUCB transplanted recipient mice at early engraftment stage, peripheral blood and hematopoietic organs were collected and analyzed up to 10 weeks post transplantation. The low dose infused group had significantly lower CD3+ (T cells) and CD56+ (NK cells) frequency in peripheral blood at 4 and 8 weeks (Fig 2A & 3A). More importantly, CD3+ (T cells) frequency was close to non-detectable in the bone marrow and spleen in the low dose infused group (Fig 2B & 2C), and CD56 (NK cells) frequency was decreased in the low dose infused group compared with the high dose infused group (Fig 3B & 3C). The absolute CD3+ and CD56+ number, displayed as fold difference, were even more dramatically decreased in the femur (Fig 2D & 3D) and the spleen (Fig 2E & 3E) of low dose infused group. Because of the substantial difference in T cell subset frequencies between the two dosage groups in bone marrow and spleen, thymuses were collected and analyzed to study T cell development and maturation. Engraftment of hCD45+ cells in the thymuses were observed in 10 out of 15 animals (66.7%) in the low dose infused group and 12 out of 14 animals (85.7%) in the high dose infused group. Interestingly, in animals with high hCD45+ frequency, the total thymocyte CD3+ frequency was lower in the low dose infused group (Fig 4A). Additionally, the low dose infused group had lower CD3+CD4+ T cell frequency (Fig 4B) and higher CD3+CD4+CD8+ T cell frequency (Fig 4C), suggesting low dose infused group had a decreased mature T cell population and increased immature T cell population in the thymus. In contrast, the low dose hUCB CD34+ cells infused group had increased hCD19 (B cells) frequency in the peripheral blood, bone marrow and spleen (Fig 5A-5C), while the absolute hCD19 (B cells), displayed as fold difference, did not show a statistically significant difference between the two groups (Fig 5D & 5E). Conclusions In summary, our findings suggest that (1) transplanted hUCB cell dosage is inversely correlated with time to engraftment (2) low transplanted hUCB cell dosage resulted in skewed immune cell population which may contribute to delayed immune recovery after allogeneic HSCT. Disclosures No relevant conflicts of interest to declare.

scholarly journals Directed Differentiation of Mobilized Hematopoietic Stem and Progenitor Cells into Functional NK Cells with Enhanced Antitumor Activity

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 811
Author(s):  
Pranav Oberoi ◽  
Kathrina Kamenjarin ◽  
Jose Francisco Villena Ossa ◽  
Barbara Uherek ◽  
Halvard Bönig ◽  
...  
Keyword(s):  
Nk Cells ◽  
Progenitor Cells ◽  
Peripheral Blood ◽  
Cell Expansion ◽  
Nk Cell ◽  
Ex Vivo ◽  
Feeder Cells ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Stem And Progenitor Cells

Obtaining sufficient numbers of functional natural killer (NK) cells is crucial for the success of NK-cell-based adoptive immunotherapies. While expansion from peripheral blood (PB) is the current method of choice, ex vivo generation of NK cells from hematopoietic stem and progenitor cells (HSCs) may constitute an attractive alternative. Thereby, HSCs mobilized into peripheral blood (PB-CD34+) represent a valuable starting material, but the rather poor and donor-dependent differentiation of isolated PB-CD34+ cells into NK cells observed in earlier studies still represents a major hurdle. Here, we report a refined approach based on ex vivo culture of PB-CD34+ cells with optimized cytokine cocktails that reliably generates functionally mature NK cells, as assessed by analyzing NK-cell-associated surface markers and cytotoxicity. To further enhance NK cell expansion, we generated K562 feeder cells co-expressing 4-1BB ligand and membrane-anchored IL-15 and IL-21. Co-culture of PB-derived NK cells and NK cells that were ex-vivo-differentiated from HSCs with these feeder cells dramatically improved NK cell expansion, and fully compensated for donor-to-donor variability observed during only cytokine-based propagation. Our findings suggest mobilized PB-CD34+ cells expanded and differentiated according to this two-step protocol as a promising source for the generation of allogeneic NK cells for adoptive cancer immunotherapy.

scholarly journals Granzyme B and perforin lytic proteins are expressed in CD34+ peripheral blood progenitor cells mobilized by chemotherapy and granulocyte colony-stimulating factor

Blood ◽  
1995 ◽  
Vol 86 (9) ◽  
pp. 3500-3506 ◽  
Author(s):  
C Berthou ◽  
JP Marolleau ◽  
C Lafaurie ◽  
A Soulie ◽  
L Dal Cortivo ◽  
...  
Keyword(s):  
Cell Line ◽  
Progenitor Cells ◽  
Peripheral Blood ◽  
Granzyme B ◽  
Cellular Adhesion ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Stimulating Factor

Granzyme B and perforin are cytoplasmic granule-associated proteins used by cytotoxic T lymphocytes and natural killer (NK) cells to kill their targets. However, granzyme B gene expression has also been detected in a non-cytotoxic hematopoietic murine multipotent stem cell line, FDCP-Mix. The objective of the present study was to investigate whether granzyme B and perforin could be expressed in human hematopoietic CD34+ cells and if present, discover what their physiologic relevance could be. The primitive CD34+ human cell line KG1a was investigated first and was found to express granzyme B and perforin. Highly purified hematopoietic stem/progenitor cells were then selected using the CD34 surface antigen as marker. Steady-state bone marrow (BM) CD34+ cells did not contain these proteins. Peripheral blood (PB) CD34+ cells, which had been induced to circulate, were also analyzed. After chemotherapy (CT) and granulocyte colony-stimulating factor (G-CSF) treatment, CD34+ cells strongly expressed mRNAs and proteins of granzyme B and perforin. In contrast, CD34+ cells mobilized by G-CSF alone were negative. Western blot analysis further showed that granzyme B and perforin proteins were identical in CD34+ cells and activated PBLs. Such proteins might be implicated in the highly efficient migration of CD34+ stem/progenitor cells from BM to PB after CT and G-CSF treatment. The cellular adhesion mechanisms involved in the BM homing of CD34+ cells are disrupted at least temporarily after CT. The Asp-ase proteolytic activity of granzyme B on extracellular matrix proteins could be used by progenitor cells for their rapid detachment from BM stromal cells and perforin might facilitate their migration across the endothelial cell barrier.

Most of the Short Term Repopulating Cells in Human Mobilized Peripheral Blood Do Not Have a Side Population (SP) Phenotype.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2867-2867
Author(s):  
M. Fischer ◽  
M. Schmidt ◽  
S. Klingenberg ◽  
C. Eaves ◽  
C. von Kalle4 ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Side Population ◽  
Isolation Procedure ◽  
Lymphoid Cells ◽  
Short Term ◽  
Hoechst 33342 ◽  
Hoechst Staining ◽  
Mobilized Peripheral Blood

Abstract The multidrug resistance transporter, ABCG2, is expressed in primitive hematopoietic stem cells from a variety of sources. These cells are detected in dual wave-length fluorescent FACS profiles as a “side population” (SP cells) on the basis of their ability to efflux the fluorescent dye, Hoechst 33342. We have previously shown that 2 types of human short term repopulating cells (STRC) can be enumerated by limiting dilution analysis of their efficient ability to regenerate exclusively myeloid cells after 3 weeks (STRC-Ms), or both myeloid and lymphoid cells after 6–12 weeks (STRC-MLs) in NOD/SCID-b2microglobulin-/- (b2m-/-) mice. Previous findings also implicated these STRCs as determinants of the rapidity of early hematologic recovery in patients transplanted with cultured mobilized peripheral blood (mPB) cells. Here we asked whether any human STRCs have an SP phenotype and hence whether the isolation of SP cells would retain the rapid repopulating activity of a clinical transplant. CD3- SP and non-SP cells were isolated by FACS from low-density (LD) mPB cells after Hoechst staining and transplanted at limiting dilutions into 117 sublethally irradiated b2m-/- mice. The numbers and types of human hematopoietic cells present in the bone marrow of these mice were subsequently monitored by FACS analysis of bone marrow cells aspirated serially, 3, 8 and 12 wks post-transplant. A verapamil-sensitive SP population was reproducibly detected in all 5 patients’ samples studied (0.039 ± 0.012% of the CD3- LD cells). The in vivo assays failed to detect either STRC-Ms or STRC-MLs in the SP fraction and all these activities were obtained from the non-SP cells. If even a single recipient of the largest dose of SP cells transplanted had been positive, this would have detected 10% of the STRCs present. Thus, >90% of all STRC-M and STRC-ML in mPB are non-SP cells. However, 4 of 40 mice transplanted with SP mPB cells produced some B-lymphoid cells only starting 12 wks post-transplant. However, this result is difficult to interpret since subjecting the STRC-Ms to the Hoechst 33342 staining and FACS isolation procedure alone eliminated their ability to generate megakaryocytic progeny in vivo, although this did not occur when these cells were just stained for CD34 and then isolated by FACS. In addition, the differentiation behaviour of STRC-MLs was not affected by the Hoechst staining and subsequent FACS isolation procedure. In summary, we demonstrate that purification of SP cells depletes human mPB transplants of STRCs, thereby raising serious concerns about the safety of any clinical use of SP cell-enriched transplants as stem cell support after myeloablation. Our results also suggest that the staining and enrichment procedure for isolating SP human cells may differentially affect the lineage potential of some types of STRCs, including those whose activity may be indispensable for rapid and multi-lineage hematologic recovery.

Age Related Changes in Hoechst 33342 Efflux Dynamics and Side Population Phenotype in Murine Bone Marrow.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3220-3220
Author(s):  
Matthew J. Greenwood ◽  
Peter M. Lansdorp
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Side Population ◽  
Hoechst 33342 ◽  
Color Flow ◽  
Hematopoietic Stem ◽  
Old Mice ◽  
Young Mice ◽  
In Cells

Abstract The mechanisms underlying the aging of the hematopoietic stem cell (HSC) compartment remain poorly understood. The ATP-binding cassette cell surface transport protein, ABCG2, has been identified as the transporter responsible for Hoechst 33342 (Hst) efflux in primitive stem cells and its expression is associated with the side population (SP) phenotype in both murine and human bone marrow (BM). ABCG2 expression and Hst efflux activity is highest in those cells with the greatest repopulating potential and is progressively downregulated during differentiation. The substrate profile of ABCG2, which includes a number of antineoplastic drugs, protoporphyrin IX and the chlorophyll breakdown product pheophorbide, suggest that ABCG2 transporters may function to protect stem cells from cytotoxic insults, a function which may be of great importance in stem cell maintenance. Amongst laboratory mice, the C57BL/6 strain is the longest lived and appears to accumulate HSC’s with age as assessed by both phenotype and colony forming assays. While the phenotypic features of the SP profile have been well characterized in both humans and young mice, little is known of the Hst efflux dynamics or phenotype of the SP profile in old and very old C57BL/6 mice. In order to further characterize the SP profile in old mice, whole BM was extracted from the femurs, tibiae, pelvis and thoracolumbar vertebral bodies of young (9–13 week) and old (95–108 week) C57BL/6 (Ly5.1) mice. Cells were stained with 5μg/ml Hst followed by staining with a combination of CD45.1 FITC, Sca1 PE, c-kit APC, CD34 FITC, biotinylated CD34 and lineage markers and strep PE-Texas Red. In addition, serial sampling of Hst incubated cells was performed to assess Hst efflux activity at 20 mins incubation through to 100mins. Six-color flow analysis was performed on a FACS Vantage™ (BD) cytometer and data analyzed using FlowJo™ software. Results show a marked increase in cells with an SP phenotype in old vs young mice (mean±SD 1.85%±0.88 vs 0.15%±0.09) which were more highly enriched for CD34-Sca1+ckit+ (22.2%±8.65 vs 8.89%±6.7) cells. Subdividing the SP profile into four regions (R1 to R4) from highest to lowest Hst efflux activity revealed that in old mice, SP cells with the highest Hst efflux activity were almost exclusively of a CD34-Sca1+ckit+ phenotype (82.3%±14.0 vs 11.5%±7.8), with a decreasing proportion of these cells represented throughout the remaining SP tail, though a significant proportion of cells within R4 remain CD34-Sca1+ckit+ (15.3%±7.83 vs 4.19±3.01). Similar patterns have been observed in both whole and lineage depleted BM. In addition, BM cells from old C57BL/6 mice show prolonged Hst efflux activity with an increase in cells in the SP gate at 100 mins (1.51%±0.50 vs 0.10%±0.06). We conclude that in old C57Bl/6 mice, cells accumulate which have the capacity to efflux Hst in agreement with previous reports of an increase in HSC number with age in this mouse strain.

Human Embryonic Stem Cell (hESC)-Derived Hematopoietic Elements Are Capable of Engrafting Primary as well as Secondary Fetal Sheep Recipients.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2685-2685
Author(s):  
A. Daisy Narayan ◽  
Jessica L. Chase ◽  
Adel Ersek ◽  
James A. Thomson ◽  
Rachel L. Lewis ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Peripheral Blood ◽  
Fetal Sheep ◽  
Hematopoietic Stem ◽  
Blood Samples ◽  
Human Dna ◽  
Cd34 Cells ◽  
Hematopoietic Activity

Abstract We used transplantation into 10 and 20 pre-immune fetal sheep recipients (55–65 days-old, term: 145 days) to evaluate the in vivo potential of hematopoietic elements derived from hESC. The in utero human/sheep xenograft model has proven valuable in assessing the in vivo hematopoietic activity of stem cells from a variety of fetal and post-natal human sources. Five transplant groups were established. Non-differentiated hESC were injected in one group. In the second and third group, embroid bodies differentiated for 8 days were injected whole or CD34+ cells were selected for injection. In the fourth and fifth group, hESC were differentiated on S17 mouse stroma layer and injected whole or CD34+ cells were selected for injection. The animals were allowed to complete gestation and be born. Bone marrow and peripheral blood samples were taken periodically up to over 12 months after injection, and PCR and flowcytometry was used to determine the presence of human DNA/blood cells in these samples. A total of 30 animals were analyzed. One primary recipient that was positive for human hematopoietic activity was sacrificed and whole bone marrow cells were transplanted into a secondary recipient. We analyzed the secondary recipient at 9 months post-injection by PCR and found it to be positive for human DNA in its peripheral blood and bone marrow. This animal was further challenged with human GM-CSF and human hematopoietic activity was noted by flowcytometry analyses of bone marrow and peripheral blood samples. Further, CD34+ cells enriched from its bone marrow were cultured in methylcellulose and human colonies were identified by PCR. We therefore conclude that hESC are capable of generating hematopoietic cells that engraft in 1° sheep recipients. These cells also fulfill the criteria for long-term engrafting hematopoietic stem cells as demonstrated by engraftment and differentiation in the 20 recipient.

Human CD34+Cells Mobilized by AMD3100 Demonstrate Enhanced NOD/SCID Repopulating Function Compared to CD34+ Cells Mobilized by Granulocyte Colony Stimulating Factor.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1962-1962 ◽  
Author(s):  
David A. Hess ◽  
Louisa Wirthlin ◽  
Timothy P. Craft ◽  
Jesper Bonde ◽  
Ryan W. Lahey ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Dna Sequences ◽  
Peripheral Blood ◽  
Paired Comparison ◽  
Fold Increase ◽  
Human Cells ◽  
Lymphoid Cells ◽  
Post Transplantation ◽  
Hematopoietic Stem ◽  
Cd34 Cells

Abstract Interactions between stromal derived factor-1 (SDF-1 or CXCL12), and its receptor CXCR4 regulate hematopoietic stem and progenitor cell retention in the bone marrow. AMD3100, a bicyclam molecule that selectively blocks the interaction between CXCL12 and CXCR4, has recently been used in clinical trials to rapidly mobilize hematopoietic progenitor cells. However, the functional properties of human stem and progenitor cells mobilized with this agent are not well characterized. Here, we directly compared the NOD/SCID repopulating function of CD34+ cells rapidly mobilized (4 hours) by AMD3100 versus CD34+ cells mobilized after 5 days of G-CSF treatment. A total of 7 HLA-matched sibling donors were leukapheresed after a single injection of 240ug/kg AMD3100. After 1 week of drug clearance, the same donor was mobilized with G-CSF, allowing a paired comparison of the repopulating function of cells mobilized by the two agents. Total CD34+ cells mobilized by AMD3100 treatment averaged 1.2±0.4x106 CD34+ cells/kg (range 0.4–2.1x106 CD34+ cells/kg), as compared to G-CSF treatment at 3.2±0.9x106 CD34+ cells/kg (range 1.7–5.7 x106 CD34+ cells/kg). Leukapheresis total mononuclear cell (MNC) fraction or purified CD34+ cells (>90% purity), were isolated and transplanted into sublethally irradiated NOD/SCID mice at varying doses. BM, spleen, and peripheral blood of mice were harvested 7–8 weeks post-transplantation and analyzed by flow cytometry for the presence or absence of engrafting human cells. Low frequency human engraftment events (<0.2% human cells) were confirmed by PCR for P17H8 alpha-satellite human DNA sequences. Injection of 1–40x106 MNC or 0.5–5x105 CD34+ cells produced consistent human engraftment and allowed limiting dilution analysis using Poisson statistics to be performed on paired samples of AMD3100 and G-CSF leukapheresis products from 3 individual patients. The calculated frequencies of NOD/SCID repopulating cells (SRC) were 1 SRC in 11.5x106 AMD3100-mobilized MNC (n=50) compared to 1 SRC in 44.8x106 G-CSF-mobilized MNC (n=55). For purified CD34+ populations, the overall frequency of repopulating cells was 1 SRC in 1.0x105 AMD3100-mobilized CDC34+ cells (n=53) compared to 1 SRC in 3.1x105 G-CSF-mobilized CD34+ cells (n=45). These data correspond to a 3–4-fold increase in overall repopulating function demonstrated by AMD3100 mobilized cells. Multilineage hematopoietic differentiation of transplanted CD34+ cells was similar for AMD3100 and G-CSF-mobilized CD34+ cells, with equivalent production of myelo-monocytic cells (CD33+CD14+), immature B-lymphoid cells (CD19+CD20+), and primitive repopulating (CD34+CD133+CD38−) cells 7–8 weeks post-transplantation. These studies indicate that human AMD3100-mobilized MNC and purified CD34+ cells possess enhanced repopulating capacity, as compared to G-CSF mobilized counterparts from the same donor. Thus, AMD3100 mobilized peripheral blood represents a rapidly obtained and highly functional source of repopulating hematopoietic stem cells for clinical transplantation procedures.

Differential Role for VLA-5 in Mobilization of Heamotopoieic Stem Cells Toward Peripheral Blood and Homing to Bone Marrow and Spleen.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2190-2190 ◽  
Author(s):  
Pieter K. Wierenga ◽  
Ellen Weersing ◽  
Bert Dontje ◽  
Gerald de Haan ◽  
Ronald P. van Os
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Peripheral Blood ◽  
Hematopoietic Stem ◽  
Late Antigen ◽  
Cell Mobilization

Abstract Adhesion molecules have been implicated in the interactions of hematopoietic stem and progenitor cells with the bone marrow extracellular matrix and stromal cells. In this study we examined the role of very late antigen-5 (VLA-5) in the process of stem cell mobilization and homing after stem cell transplantation. In normal bone marrow (BM) from CBA/H mice 79±3 % of the cells in the lineage negative fraction express VLA-5. After mobilization with cyclophosphamide/G-CSF, the number of VLA-5 expressing cells in mobilized peripheral blood cells (MPB) decreases to 36±4%. The lineage negative fraction of MPB cells migrating in vitro towards SDF-1α (M-MPB) demonstrated a further decrease to 3±1% of VLA-5 expressing cells. These data are suggestive for a downregulation of VLA-5 on hematopoietic cells during mobilization. Next, MPB cells were labelled with PKH67-GL and transplanted in lethally irradiated recipients. Three hours after transplantation an increase in VLA-5 expressing cells was observed which remained stable until 24 hours post-transplant. When MPB cells were used the percentage PKH-67GL+ Lin− VLA-5+ cells increased from 36% to 88±4%. In the case of M-MPB cells the number increased from 3% to 33±5%. Although the increase might implicate an upregulation of VLA-5, we could not exclude selective homing of VLA-5+ cells as a possible explanation. Moreover, we determined the percentage of VLA-5 expressing cells immediately after transplantation in the peripheral blood of the recipients and were not able to observe any increase in VLA-5+ cells in the first three hours post-tranpslant. Finally, we separated the MPB cells in VLA-5+ and VLA-5− cells and plated these cells out in clonogenic assays for progenitor (CFU-GM) and stem cells (CAFC-day35). It could be demonstared that 98.8±0.5% of the progenitor cells and 99.4±0.7% of the stem cells were present in the VLA-5+ fraction. Hence, VLA-5 is not downregulated during the process of mobilization and the observed increase in VLA-5 expressing cells after transplantation is indeed caused by selective homing of VLA-5+ cells. To shed more light on the role of VLA-5 in the process of homing, BM and MPB cells were treated with an antibody to VLA-5. After VLA-5 blocking of MPB cells an inhibition of 59±7% in the homing of progenitor cells in bone marrow could be found, whereas homing of these subsets in the spleen of the recipients was only inhibited by 11±4%. For BM cells an inhibition of 60±12% in the bone marrow was observed. Homing of BM cells in the spleen was not affected at all after VLA-5 blocking. Based on these data we conclude that mobilization of hematopoietic progenitor/stem cells does not coincide with a downregulation of VLA-5. The observed increase in VLA-5 expressing cells after transplantation is caused by preferential homing of VLA-5+ cells. Homing of progenitor/stem cells to the bone marrow after transplantation apparantly requires adhesion interactions that can be inhibited by blocking VLA-5 expression. Homing to the spleen seems to be independent of VLA-5 expression. These data are indicative for different adhesive pathways in the process of homing to bone marrow or spleen.

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