OBJECTIVE: To investigate the effect of Rheb1 in the development of mouse megakaryocyte-erythroid progenitor cells and its related mechanism. METHODS: Rheb1 was specifically knocked-out in the hematopoietic system of Vav1-Cre;Rheb1^fl/fl mice(Rheb1^Δ/Δ mice). Flow cytometry was used to detect the percentage of red blood cells in peripheral blood and erythroid cells in bone marrow in Vav1-Cre;Rheb1^fl/fl mice and control mice. The CFC assay was used to detect the differentiation ability of Rheb1 KO megakaryocyte-erythroid progenitor cells and control cells. Real-time fluorescence quantification PCR was used to detect the relative expression of PU.1,GATA-1,GATA-2,CEBPα and CEBPβ of Rheb1 KO megakaryocyte-erythroid progenitor cells and control cells. Rapamycin was added to the culture medium, and it was used to detect the changes in cloning ability of megakaryocyte-erythroid progenitor cells from wild-type mice in vitro. RESULTS: After Rheb1 was knocked out, the development and stress response ability of megakaryocyte-erythroid progenitor cells in mice were weaken and the differentiation ability of megakaryocyte-erythroid progenitor cells in vitro was weaken. Moreover, the expression of GATA-1 of megakaryocyte-erythroid progenitor cells was decreased. Further, rapamycin could inhibit the differentiative capacity of megakaryocyte-erythroid progenitor cells in vitro. CONCLUSION Rheb1 can regulate the development of megakaryocyte-erythroid progenitor cells probably through the mTOR signaling pathway in mice.
Animals ; Cell Differentiation ; Erythrocytes ; Flow Cytometry ; Megakaryocyte-Erythroid Progenitor Cells ; Megakaryocytes ; Mice ; Signal Transduction

No abstract available.
Down Syndrome* ; Humans ; Infant, Newborn* ; Megakaryocyte Progenitor Cells*

No abstract available.
Blast Crisis* ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive* ; Megakaryocyte Progenitor Cells*

Self-renewal and differentiation are hallmarks of stem cells and controlled by various intrinsic and extrinsic factors. Increasing evidence indicates that estrogen (E2), the primary female sex hormone, is involved in regulating the proliferation and lineage commitment of adult and pluripotent stem cells as well as modulating the stem cell niche. Thus, a detailed understanding of the role of E2 in behavior of stem cells may help to improve their therapeutic potential. Recently, it has been reported that E2 promotes cell cycle activity of hematopoietic stem and progenitor cells and induces them to megakaryocyte-erythroid progenitors during pregnancy. This study paves the way towards a previously unexplored endocrine mechanism that controls stem cell behavior. In this review, we will focus on the scientific findings regarding the regulatory effects of E2 on the hematopoietic system including its microenvironment.
Adult ; Cell Cycle ; Estrogens* ; Female ; Hematopoiesis ; Hematopoietic Stem Cells* ; Hematopoietic System ; Humans ; Megakaryocyte-Erythroid Progenitor Cells ; Pluripotent Stem Cells ; Pregnancy ; Stem Cell Niche ; Stem Cells

OBJECTIVETo build a protocol of separation and induction of megakaryocytes derived from cord blood mononuclear cells.

METHODSRed blood cells were precipitated by hydroxyethyl starch (HES). Mononuclear cells were obtained by density gradient centrifugation with Ficoll. The inducing efficiencies of megakaryocytes by using of different cytokine cocktails and culture media were analyzed.

RESULTSThe best choice for erythrocyte sedimentation and high efficiency of nucleated cells retrieving were obtained by using of 1.5% HES. The isolated cord blood mononuclear cells were cultured with domestic serum-free medium supplemented with 116t (IL-11, IL-6, TPO), st36(SCF, TPO, IL-3, IL-6), pt36 (PDGF,TPO,IL-3,IL-6) or pst36 for 7 days. St36 group (50 ng/ml SCF, 50 ng/ml TPO, 20 ng/ml IL-3 and 50 ng/ml IL-6) yielded the most CD41/CD61 positive [(6.79±1.97)×10⁴]. The cell viability [(82.85 ± 0.64)%] of st36 group by using of imported serum-free medium was better than [(60.90±6.93)%] that in domestic medium on day 7 after induction, and CD41/CD61 positive cells count [(18.60±1.97)×10⁴] were more than domestic serum-free medium group. Therefore, we chose imported serum-free medium containing st36 to induce cord blood mononuclear cells. After a prolonged culture, the total cell numbers increased accompanied with an elevated percentage of CD41/CD61 positive cells, which reached (54.27 ± 6.31)% on day 14. Wright-Giemsa staining showed that different phase cells, such as megakaryoblast, promegakaryocyte and granular megakaryocyte, occurred after 10 days'culture. Clone forming unit-megakarocytes (CFU-MK) assay showed that the colonies count increased with the prolonged incubation. CFU-MK colonies were [1 236.0±32.9] on day 14, which was higher than that in medium without induction (P<0.01). Platelets from megakaryocytes showed agglutination function after 10 days'culture.

CONCLUSION1.5% HES was the best solution to precipitate erythrocytes. The combination of an imported serum-free medium with IL-3, IL-6, SCF and TPO showed better induction efficiency than domestic medium or other cytokine cocktails. Meanwhile, induced megakaryocytes produced functional platelets.

Cell Culture Techniques ; Cell Differentiation ; Cell Division ; Cell Separation ; methods ; Cells, Cultured ; Culture Media, Serum-Free ; Fetal Blood ; cytology ; Humans ; Megakaryocyte Progenitor Cells ; cytology

OBJECTIVETo investigate the effects of total saponins from Sanguisorba officinalis (DYS) on hematopoietic cell proliferation, differentiation and the expression level of IL-3R and c-kit.

METHODBaf3 and 32D cells were cultured with or without IL-3, then the cells were exposed to DYS in different concentrations of 5, 10, 20, 30 and 40 mg x L(-1) for 24, 48, 72 and 96 hours separately. After that, the cell proliferation and differentiation capacity were determinated by the methods of CCK8 and Giemsa staining separately. The effects of DYS on the expression level of IL-3 receptor in Baf3 cells and the expression level of c-kit in 32D cells were determinated using RT-PCR.

RESULTDYS promotes alone proliferation of Baf3 cells and 32D cells after 48 h. In contrast to control cells, 32D cells containing DYS without IL-3 form many large clusters. DYS also increases the proliferation when cultured with IL-3. High concentration of DYS induce alone the differentiation of 32D cells and increase alone the number of the polyploidy megakaryocyte. Moreover, DYS increases alone the expression level of IL-3R in Baf3 cells and the expression level of c-kit in 32D cells separately.

CONCLUSIONOur data shows DYS can promote alone proliferation and differentiation of megakaryocyte progenitor cells. The proliferative and differentiative effect of DYS on megakaryocyte progenitor cells is correlated to the up-regulation of IL-3 receptor and c-kit expression.

Animals ; Cell Differentiation ; drug effects ; genetics ; Cell Line ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Gene Expression ; drug effects ; Interleukin-3 ; pharmacology ; Megakaryocyte Progenitor Cells ; drug effects ; metabolism ; Mice ; Proto-Oncogene Proteins c-kit ; genetics ; Receptors, Interleukin-3 ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Sanguisorba ; chemistry ; Saponins ; pharmacology ; Time Factors

The purpose of this study was to explore the differences in megakaryocyte progenitor ex vivo expansion between CD34+ cells derived from human umbilical cord blood (CB) and bone marrow (BM). Mononuclear cells (MNCs) were obtained from CB or BM by Ficoll-Hypaque density gradient separation. CD34+ cells were purified by magnetic cell sorting (MACS). The selected CD34+ cells were seeded in serum-free conditions stimulated with thrombopoietin (TPO), TPO+interleukin 11 (IL-11), or TPO+IL11+heparin for 14 days. Amplification product (CD34+, CD41a+, and CD34+ CD41a+ cells) immunophenotypes, megakaryocyte apoptosis rates and the DNA content were measured by fluorescence-activated cell sorting (FACS). The colony-forming units of granulocytes and monocytes (CFU-GM), burst-forming units of erythrocytes (BFU-E), and colony-forming units of megakaryocytes (CFU-Mk) were also evaluated by the colony-forming units (CFU) assay. The results indicated that CD34+ cells derived from CB showed higher expansion ability of total cell counts, CD41a+ and CD34+ CD41a+ cells than those derived from BM for all days 14 of culture (p<0.05, respectively). There were no significant differences in CFU-GM, BFU-E, and total CFU-Mk counts between CB and BM-derived CD34+ cells on day 0 (p>0.05, respectively), but CB-derived CFU-Mk seemed mainly large colonies, and the number of large colonies was higher than that from BM (p<0.05) on day 0. There were no significant differences in expansion ability of CFU-GM between CB and BM-derived cells on days 7, 10, and 14 of culture (p > 0.05, respectively), but the expansion ability of BFU-E and CFU-Mk derived from CB cells was higher than that from BM (p<0.05, respectively). There were no significant differences in apoptosis rates of megakaryocyte from two source cells for days 14 of culture. Megakaryocytes derived from CB mostly showed the 2N DNA content (>90%) for days 14 of culture, while those cells derived from BM showed the increased DNA content, and 4N, 8N or more ploidy cells gradually increased with prolonging of culture time. It is concluded that CB-derived CD34+ cells have a greater proliferation potential than that derived from BM, which is therefore proven to be a better cell source for megakaryocyte progenitor expansion in vitro.
Antigens, CD34 ; Bone Marrow Cells ; cytology ; immunology ; Cell Culture Techniques ; methods ; Cell Differentiation ; Cell Division ; Cell Separation ; Cells, Cultured ; Erythroid Precursor Cells ; cytology ; Fetal Blood ; cytology ; immunology ; Humans ; Megakaryocyte Progenitor Cells ; cytology ; immunology

This study was purposed to investigate the biological characteristics and immunogenicity changes of ex vivo expanded megakaryocyte progenitors from human umbilical cord blood CD34(+) cells in order to provide experimental basis for clinical application of ex vivo expanded umbilical cord blood megakaryocyte progenitor cells. Mononuclear cells (MNCs) were obtained from umbilical cord blood by Ficoll-Hyapaque density gradient separation. CD34(+) cells were enriched by magnetic cell sorting (MACS). The selected CD34(+) cells were seeded in serum-free medium stimulated with thrombopoietin (TPO, 50 ng/ml), interleukin 11 (IL-11, 50 ng/ml), and heparin (25 U/ml) for 14 days. The immunophenotyping (CD34(+), CD41a(+), CD61(+), CD34(+) CD41a(+) and CD34(+) CD61(+) cells) of amplificated products, matured megakaryocyte apoptosis, and expression of human leukocyte antigen (HLA) class I and class II molecules were measured by fluorescence-activated cell sorter (FACS). The number of colony-forming units-megakaryocyte (CFU-Mk) was also evaluated by CFU-Mk assay. The results showed that the umbilical cord blood CD34(+) mononuclear cells could be effectively differentiated into megakaryocytes. The peak expression ratios of CD41a(+) and CD61(+) cells were all at 14th days, while that of CD34(+) CD41(+) and CD34(+) CD61(+) cells were at 7th day [(3.41 +/- 2.80)% and (1.89 +/- 1.43)%, respectively]. The expansion times of large and small CFU-Mk reached peak at 7th day (20.66 +/- 32.79) and 10th day (435.62 +/- 482.65), respectively. The apoptotic rates of megakaryocytes at 7th, 10th, 14th day were (19.48 +/- 9.64)%, (26.87 +/- 9.03)%, and (52.46 +/- 11.74)%, respectively. The apoptotic rate of megakaryocytes had no significant difference in 7 and 10 days culture (p > 0.05), while that significantly increased in culture for 14 day culture, compared with culture for 7 and 10 days (p < 0.05, respectively). The expression of HLA class I and class II molecules on megakaryocytes decreased along with the prolongation of expansion time and sharply decreased in 0 to 10 days. It is concluded that the cytokines of TPO, IL-11, and heparin can promote the expansion of megakaryocyte progenitors from umbilical cord blood CD34(+) mononuclear cells effectively in vitro. The peaked expansion times of large CFU-Mk, the peaked expression ratios of CD34(+) CD41(+) and CD34(+) CD61(+) cells were all at 7th day. So the culture for 7 days appeared to be the optimal duration of expanding megakaryocyte progenitors.
Antigens, CD34 ; immunology ; Cell Differentiation ; Cell Division ; Cell Separation ; Cells, Cultured ; Fetal Blood ; cytology ; immunology ; Humans ; Megakaryocyte Progenitor Cells ; cytology

OBJECTIVETo study the expansion potential of megakaryocyte progenitor cells (MPC) from human placenta tissue CD133+ (PT-CD133+) cells.

METHODSPT-CD133+ cells were purified from mononuclear cells (MNC) by magnetic activated cell sorting (MACS) and seeded in serum-free liquid culture medium supplemented with thrombopoietin (TPO), interleukin-3 (IL-3), and stem cell factor (SCF) to expand MPC. At day 7, 10 and 14, the total cell number was counted and the dynamic changes of CD133, CD34, and CD41 antigens expression during ex-vivo expansion were analyzed by flow cytometry (FCM). PT-CD133+ cells at different expansion time were collected and cultured in collagen semisolid medium for colony forming units-megakaryocyte (CFU-MK) assay.

RESULTSPT-CD133+ cells could be optimally expanded at day 7 by 13 +/- 2 fold increase in serum-free liquid culture systems and the total cell number was expanded by 160 fold at day 14. With the expansion time going on, the expression of CD133, CD34 decreased and that of CD41 increased. The expanded megakaryocytes were immature and no sign of platelet formation. Both PT-CD133+ cells before and after expansion could form CFU-MK, the total number of CFU-MK peaked at day 10 of expansion by 54 +/- 10 fold increase.

CONCLUSIONHuman PT-CD133+ cells have a high capacity of MPC expansion, 10 days culture could give rise to the maximum number of CFU-MK.

AC133 Antigen ; Antigens, CD ; Cell Differentiation ; Cells, Cultured ; Female ; Glycoproteins ; Humans ; Megakaryocyte Progenitor Cells ; cytology ; Peptides ; Placenta ; cytology ; Pregnancy

OBJECTIVEIdiopathic thrombocytopenic purpura (ITP) is a hemorrhagic disease in children with blood platelets redundant destruction caused by chaotic immunological mechanism. However, some patients with ITP with negative platelet-associated antibody and ineffective adrenal cortical hormone therapy probably have special pathogenesis. It is indicated that the human cytomegalovirus (HCMV) can incubate in haemopoietic stem cell/ancestral cell to inhibit its generation and differentiation. Therefore, the study was designed to investigate HCMV-late mRNA expression in megakaryoblast for the purpose of examining the pathogenesis of ITP and to examine the effectiveness of ganciclovir on ITP.

METHODSColony forming unit-megakaryocyte (CFU-MK) of 46 ITP patients with HCMV infection were incubated. Reverse transcription-polymerase chain reaction (RT-PCR) was subsequently used for HCMV-late mRNA detection. Ganciclovir therapy was given to both positive group and negative group for comparison of therapeutic effectiveness.

RESULTSNineteen out of 46 CFU-MK culture cell specimens with positive HCMV-DNA by PCR or positive CMV-IgM by enzyme linked immunosorbent assay (ELISA) from serum of peripheral blood showed positive for HCMV-late mRNA. While, the remaining 27 were negative. Sixteen positive responders to ganciclovir therapy were observed amongst those with positive HCMV-DNA. Whereas, only 4 positive responders to ganciclovir therapy were noticed amongst those with negative HCMV-DNA. The curative effectiveness in positive group was significantly higher than that in negative group (P < 0.01).

CONCLUSIONHCMV can directly infect CFU-MK, which might be one of the mechanisms responsible for ITP. Ganciclovir is an effective therapy resulting in an increase in thrombocyte in ITP patients whose HCMV-late mRNA was positive in their CFU-MK.

Adolescent ; Antibodies, Viral ; immunology ; Antiviral Agents ; therapeutic use ; Blood Platelets ; drug effects ; immunology ; Cells, Cultured ; Child ; Child, Preschool ; Cytomegalovirus ; drug effects ; genetics ; pathogenicity ; Cytomegalovirus Infections ; drug therapy ; genetics ; immunology ; Enzyme-Linked Immunosorbent Assay ; Female ; Ganciclovir ; therapeutic use ; Humans ; Immunoglobulin M ; immunology ; Infant ; Male ; Megakaryocyte Progenitor Cells ; drug effects ; metabolism ; Purpura, Thrombocytopenic, Idiopathic ; complications ; drug therapy ; immunology ; RNA, Messenger ; RNA, Viral ; drug effects ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction