Proliferation extent of CD34+ cells as a key parameter to maximize megakaryocytic differentiation of umbilical cord blood-derived hematopoietic stem/progenitor cells in a two-stage culture protocol

The monoculture of cord-blood-derived CD34+ cells by an automated, membrane-based dynamic perfusion system with a novel cytokine cocktail

Human leukocyte antigen (HLA)-matched cord blood (CB) transplantation is a procedure for the treatment of certain hematological malignancies, hemoglobinopathies, and autoimmune disorders. However, one of the challenges is to provide a sufficient number of T cell-depleted hematopoietic stem and progenitor cells. Currently, only 4%-5% of the CB units stored in CB banks contain enough CD34⁺ cells for engrafting 70-kg patients. To support this clinical need, we have developed an automated expansion protocol for CB-derived CD34⁺ cells in the Quantum system's dynamic perfusion bioreactor using a novel cytokine cocktail comprised of stem cell factor (SCF), thrombopoietin (TPO), fms-like tyrosine kinase 3 ligand (Flt-3L), interleukin-3 (IL-3), IL-6, glial cell line-derived neurotrophic factor (GDNF), StemRegenin 1 (SR-1), and a fibronectin-stromal-cell-derived factor-1 (SDF-1)-coated membrane. In an 8-day expansion of a 2 × 10⁶ positively selected CD34⁺ cell inoculum from 3 donor lineages, the mean cell harvest and cell viability were 1.02 × 10⁸ cells and 95.5%, respectively, and the mean frequency of the CD45⁺CD34⁺ immunophenotype was 54.3%. The mean differentiated cell frequencies were 0.5% for lymphocytes, 15.8% for neutrophils, and 15.4% for platelets. These results demonstrate that the automated monoculture protocol can support the expansion of CD34⁺ cells with minimal lymphocyte residual.

The upregulation of Gata transcription factors family and FOG-1 in expanded and differentiated cord blood-derived CD34+ hematopoietic stem cells to megakaryocyte lineage during co-culture with cord blood mesenchymal stem cells

BACKGROUND

Umbilical cord blood (UCB) has improved into an attractive and alternative source of allogeneic hematopoietic stem cells (all-HSCs) in clinics and, research for three decades. Recently, it has been shown that the limited cell dose of, this valuable source can be enhanced by the ex vivo expansion of cells in many, ways. We evaluated the expression of the Gata transcription factors family and FOG-1, in expanded and differentiated cord blood-derived CD34 + hematopoietic stem cells to, megakaryocytes lineage., Methods: Separated mononuclear cells were cultured in DMEM complete medium., Harvested cells as a mesenchymal stem cell at 85 % confluency were cultured with, trypsin/EDTA and in 24-well plates. The characteristic analyses of isolated UCB- MSCs, were done by flow cytometry and adipogenic, chondrogenic, and osteogenic, differentiation assays. MACS purified UCB-CD34 + hematopoietic cells cultivated and, differentiated to megakaryocyte progenitor cells in the presence of cytokine cocktail, with UCB-MSCs. Then, the GATA1, GATA2, GATA3, and FOG-1 genes expression, after differentiation to megakaryocyte progenitor cells were performed by quantitative, real-time polymerase chain reaction (PCR)., Results: In this study, the results of real-time-PCR showed that the fold change, expression of GATA-1, FOG-1, and GATA-2 genes after co-culturing with UCB-MSCs, significantly increased to 7.3, 4.7, and 3.3-fold in comparison with control groups;respectively., Conclusion: UCB-MSCs can increase the expansion and differentiation of UCBCD34 + , to megakaryocyte progenitor cells through upregulation of GATA-1, GATA-2, and FOG-1 gene expression.

Nanocurcumin as a novel stimulator of megakaryopoiesis that ameliorates chemotherapy-induced thrombocytopenia in mice

AIMS

Platelet production improvement can resolve concerns about the limitations of external platelet supply and platelet transfusion in thrombocytopenia patients. To this end, scientists encourage to induce the generation of megakaryocyte and platelet. Curcumin is a safe ingredient of turmeric that affects various cellular pathways. The effect of this component on platelet production has not been yet reported.

MAIN METHODS

Our in vitro experiments include the investigation of the effects of nanocurcumin on megakaryocytes production from K562 cells and hematopoietic stem cells via megakaryocyte markers expression, DNA content, ROS, and morphologic analysis, and CFC assay. The regulatory functions of MAPKs pathways were also determined. In the in vivo study tissue distribution of nanocurcumin was determined and two treatment schedules were used to evaluate the capability of nanocurcumin to prevent the occurrence of Busulfan-induced thrombocytopenia in the mouse model.

KEY FINDING

In vitro evidences demonstrated that nanocurcumin can induce MK production from K562 cells and hematopoietic stem cells. Inhibition of ERK1/2 and JNK pathways arrested this activity. In vivo experiments showed the uptake of nanocurcumin by tissues in mice. Administration of nanocurcumin could preserve bone marrow integrity and increase of the number of circulating platelets in the Busulfan-treated mice models.

SIGNIFICANCE

Our results have demonstrated that nanocurcumin administration can be useful for the improvement of megakaryocytes and platelet generation in vitro. This component may be exerting these beneficial effects on megakaryopoiesis by modulating ERK1/2 and JNK pathways. As well as nanocurcumin has the potential to prevent thrombocytopenia in chemotherapy threated mice.

Explant culture: A relevant tool for the study of telocytes

Telocytes are cells present in the stroma of various tissues including the prostate. The detection of telocytes is still very much dependent on obtaining ultrastructural data that show the presence of telopodes, which are cytoplasmic projections that alternate between dilated regions, the podoms, and thin segments, the podomers. These structures are the distinctive characteristics of the telocytes. Thus, in vitro assays are important for the study of telocytes, which are more easily identified in culture, which also enables the experimental manipulation of these cells. The isolation of telocytes per se does not allow the analysis of the behavior of these cells in relation to other cell types in a given organ. In this sense, in the prostate, explants could be a useful tool for the study of telocytes. The present study obtained prostatic explants and evaluated the influence of recombinant proteins, scattering factor (SCF) and stromal-derived factor 1 (SDF-1), which could impact on the migration of CD34-positive cells. Telocytes migrate out of explants and SDF-1 stimulates the proliferation and formation of telocyte networks in vitro. Telocytes are not smooth muscle cell progenitors in the prostate; on the contrary, they are CD90- and CD44-negative cells and, hence, have limited progenitor capacity. The present study demonstrated that explants are useful tools to elucidate the nature of telocytes and their functions.

Effect of Mesenchymal Stem Cell-derived Microvesicles on Megakaryocytic Differentiation of CD34+ Hematopoietic Stem Cells

Purpose: Mesenchymal stem cells (MSCs) release hematopoietic cytokines, growth factors, and Microvesicles (MVs) supporting the hematopoietic stem cells (HSCs). MVs released from various cells, playing a crucial role in biological functions of their parental cells. MSC-derived MVs contain microRNAs and proteins with key roles in the regulation of hematopoiesis. Umbilical cord blood (UCB) is a source for transplantation but the long-term recovery of platelets is a main problem. Therefore, we intend to show that MSC-MVs are able to improve the differentiation of UCB-derived CD34⁺ cells to megakaryocyte lineage.

Methods: In this descriptive study, MSCs were cultured in DMEM to collect the culture supernatant, which was ultracentrifuged for the isolation of MVs. HSCs were isolated from UCB using MACS method and cultured in IMDM supplemented with cytokines and MVs in three different conditions. Megakaryocyte differentiation was evaluated through the expression of specific markers and genes after 72 hours, and the data was analyzed by t test (P<0.05).

Results: The expression of specific megakaryocyte markers (CD41 and CD61) in the presence of different concentrations of MSC-MVs did not show any significant difference. Also, the expression of specific genes of megakaryocyte lineage was compared with control group. The expression of GATA2 and c-Mpl was significantly increased, GATA1 was not significantly decreased, and FLI1 was significantly decreased.

Conclusion: MSC-MVs could improve the expression of specific megakaryocyte genes; however, there was no significant expression of CD markers. Further studies, including the evaluation of late stages of megakaryocyte differentiation, are required to evaluate platelet production and shedding

Evaluation of human cord blood CD34+ hematopoietic stem cell differentiation to megakaryocyte on aminated PES nanofiber scaffold compare to 2-D culture system

CONTEXT

Recently, umbilical cord blood (UCB) has been recognized as a suitable potential source of hematopoietic stem/progenitor cells (HSPCs) for transplantation. Lengthy thrombocytopenia after UCB transplantation is a major problem because of insufficient megakaryocyte (Mk) progenitors, which results in delayed platelet recovery. Frequent allogenic platelet transfusion leads to resistance to platelet units and higher risk of transmission of pathogenic agent.

OBJECTIVE

Ex vivo expansion of HSPCs and their differentiation to Mk progenitors on aminated PES nanofiber could lead to faster platelet recovery after UCB transplantation.

MATERIALS AND METHODS

CD34 cells were positively enriched using the MidiMACS system. CD34(+) cells were seeded onto conventional culture and aminated PES scaffold. The proliferation of CD34(+) cells, and also their differentiation into Mk progenitors, were evaluated. We used the flow cytometric method for analyzing CD41 and CD61 markers and real-time PCR for the expression level of transcription factors, as NF-E2 and GATA-1.

RESULTS

This study indicated increased CD34(+) cell population in aminated PES compared to the conventional system. After differentiation, the amount of CD41/CD61-expressing cells and the quantity of NF-E2 expression level increased in the aminated PES versus the 2-D system. The quantity of GATA-1 expression level was reduced on CD41/CD61(+) cells compared to CD34(+) cells, with no difference between the aminated PES and the conventional system.

DISCUSSION

Aminated PES nanofiber could have more effect on the proliferation of CD34(+) cells and Mk differentiation than the conventional culture.

CONCLUSION

Injection of the expanded cells and differentiated Mk progenitors, along with the transplantation of UCB stem cells might accelerate recovery of platelets and decrease the period of thrombocytopenia after transplantation.

Developing a co-culture system for effective megakaryo/thrombopoiesis from umbilical cord blood hematopoietic stem/progenitor cells

BACKGROUND AIMS

Platelet transfusion can be a life-saving procedure in different medical settings. Thus, there is an increasing demand for platelets, of which shelf-life is only 5 days. The efficient ex vivo biomanufacturing of platelets would allow overcoming the shortages of donated platelets.

METHODS

We exploited a two-stage culture protocol aiming to study the effect of different parameters on the megakaryo/thrombopoiesis ex vivo. In the expansion stage, human umbilical cord blood (UCB)-derived CD34(+)-enriched cells were expanded in co-culture with human bone marrow mesenchymal stromal cells (BM-MSCs). The megakaryocytic commitment and platelet generation were studied, considering the impact of exogenous addition of thrombopoietin (TPO) in the expansion stage and a cytokine cocktail (Cyt) including TPO and interleukin-3 in the differentiation stage, with the use of different culture medium formulations, and in the presence/absence of BM-MSCs (direct versus non-direct cell-cell contact).

RESULTS

Our results suggest that an early megakaryocytic commitment, driven by TPO addition during the expansion stage, further enhanced megakaryopoiesis. Importantly, the results suggest that co-culture with BM-MSCs under serum-free conditions combined with Cyt addition, in the differentiation stage, significantly improved the efficiency yield of megakaryo/thrombopoiesis as well as increasing %CD41, %CD42b and polyploid content; in particular, direct contact of expanded cells with BM-MSCs, in the differentiation stage, enhanced the efficiency yield of megakaryo/thrombopoiesis, despite inhibiting their maturation.

CONCLUSIONS

The present study established an in vitro model for the hematopoietic niche that combines different biological factors, namely, the presence of stromal/accessory cells and biochemical cues, which mimics the BM niche and enhances an efficient megakaryo/thrombopoiesis process ex vivo.