Effects of lysophosphatidic acid (LPA), an extracellular phospholipid signal, on the proliferation of rat embryonic neural stem cells (NSCs) and their differentiation into microtubule-associated protein 2 (MAP2)-positive and choline acetyltransferase (ChAT)-positive, i.e. cholinergic-committed neurons, were observed in vitro by [(3)H]-thymidine incorporation, immunocytochemistry, Western blot and other techniques. The results showed that: (1) Lower concentrations of LPA (0.01~1.0 mumol/L) dose-dependently enhanced the uptake of [(3)H]-thymidine by NSCs cultured in specific serum-free medium, indicating a significant promotive action of LPA on the proliferation of NSCs. (2) After fetal bovine serum which induces and commences the differentiation of NSCs, was used in the medium, the lower concentrations of LPA increased the percentages of both MAP2- and ChAT-immunoreactive neurons, with a peak at 0.1 mumol/L LPA in two cases. (3) The promotive effects of LPA on the differentiation of MAP2- and ChAT-positive neurons were also supported by the up-regulation of the expressions of both MAP2 and ChAT proteins detected by Western blot. (4) At the early phase of differentiation of NSCs, the cell migration and neurite extension were enhanced significantly by lower dosages of LPA under phase-contrast microscope. These results suggest that LPA within certain lower range of concentrations promotes the proliferation of NSCs and their differentiation into unspecific MAP2-positive and specific cholinergic-committed neurons, and also strengthens the migration and neurite extension of the newly-generated neuronal (and also glial as reported elsewhere) progenitors.
Animals ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cholinergic Neurons ; cytology ; Embryonic Stem Cells ; drug effects ; Lysophospholipids ; pharmacology ; Neural Stem Cells ; drug effects ; Rats

OBJECTIVETo analyze the influence of retinoic acid (RA) on the undifferentiated state and EB formation abilities of human embryonic stem cells.

METHODSThe biological characteristics of H9 ESCs after RA treatment were characterized by real-time PCR, MTS proliferation assay and immunofluorescence staining. The expression of three germ layers markers, osteogenic differentiation markers and adipogenic differentiation markers in H9-differentiated embryoid bodies (EBs) with RA treatment were quantified by real time PCR.

RESULTSThe proliferation of H9 ESCs in the early logarithmic growth phase was accelerated by RA treatment. In addition, RA induced differentiation of H9 ESC coupled with morphology changes, decreased expression of undifferentiated markers Oct4, Nanog, Sox2 and OCT4 mRNA binding protein Lin28 at mRNA level, and reduced expression of Oct4 at protein level. RA induced formation of cavities in EBs. Real time PCR results showed that the expressions of ectodermal markers: NeuroD1, Noggin; mesodermal markers: Brachyury, Twist and endodermal markers: AFP, GATA-4 were significantly increased (P < 0.05), especially for AFP (P < 0.01), by RA treatment in a dose-dependent manner. In addition, the expression of adipogenic differentiation marker C/EBPalpha was increased while the osteogenic differentiation marker OPN was decreased in EBs after RA treatment for 5 days.

CONCLUSIONSHigh concentrations of RA induced the loss of stemness in H9 ESCs and excessive differentiation in EBs, and damaged the balance between osteogenic and adipogenic differentiation during early EB differentiation, which may be relevant to the congenital malformations.

Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Embryonic Stem Cells ; cytology ; drug effects ; Humans ; Tretinoin ; pharmacology

Tumor Stem/Progenitor Cells are characterized by undifferentiation/hypodifferention, self-renewal, differentiation potential, which is responsible for tumor occurrence, growth and metastasis. The theory about tumor stem/progenitor cells provides a new insight to recognize the origin and essence of tumors. Gaining a better insight into the origin of tumor stem/progenitor cells and the mechanisms of tumor stem/progenitor cells resistance to chemotherapy may lead to new therapeutic targets and better anticancer strategies. This review summarizes recent progress of research on the origin of tumor stem/progenitor cells and multidrug resistance.
Cell Line, Tumor ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Humans ; Neoplasms ; drug therapy ; Neoplastic Stem Cells ; drug effects ; Stem Cells ; drug effects

OBJECTIVETo investigate the roles of telomere and telomerase in the effect of ginsenoside Rg1 to delay hematopoietic stem cell senescence.

METHODSca-1(+) HSC was isolated by magnetic cell sorting(MACS) and divided into five groups: the control group, the aged model group, the Rg1 group, the Rg1 treated aged group and the Rg1 delayed aged group. The changes of cells were observed by senescence-associated beta-Galactosidase (SA-beta-Gal) staining. Cell cycle assay and culture of mixed hematopoietic progenitor cell were used to investigate the effect of ginsenoside Rg1 to delay Sca-1(+) HSC senescence. Telomere length and telomerase activity were detected by southern blotting and TRAP-PCR-SYBR Green staining.

RESULTCompared with aged model group, the percentage of positive cells expressed SA-beta-Gal and the number of cells entered G1 phase were decreased and the number of colony of mixed hematopoietic progenitor was increased. It showed markedly decreased in the shortening of telomere length and reinforcing in the telomerase activity to Rg1 treated aged group and Rg1 delayed aged group. The change of Rg1 delayed aged group was significantly higher than Rg1 treated aged group.

CONCLUSIONActivation of telomerase and prolonging of telomere length might be involved in the process of ginsenoside Rg1 to delay and treat the senescence of Sca-1(+) HSC.

Cellular Senescence ; drug effects ; Ginsenosides ; pharmacology ; Hematopoietic Stem Cells ; drug effects ; physiology ; Telomerase ; metabolism ; Telomere ; drug effects

OBJECTIVETo investigate the effect of propofol on the proliferation and differentiation of rat embryonic neural stem cells in vitro.

METHODSEmbryonic neural stem cells of fetal Wistar rats (gestational age of 14-16 days) in primary culture, after identification for nestin expression, were divided into control group, introlipid group, and propofol groups (treated with propofol at the doses of 5, 25, 50, and 100 µmol/L). The changes in the proliferation of the embryonic neural stem cells after the treatments were observed using Brdu incorporation assay. In the course of induced differentiation of the embryonic neural stem cells, 50 µmol/L propofol was added in the cells to assess its impact on the differentiation of the cells by immunohistochemical detection of NeuN and GFAP expressions.

RESULTSMore than 95% of the embryonic neural stem cells in primary culture were Nestin-positive. The percentages of Brdu-positive cells showed no significant changes after treatment with different concentrations of propofol, whereas the addition of 50 µmol/L propofol resulted in a significant increase of NeuN-positive cell percentage to (23.1∓0.9)% as compared with that of (13.4∓0.8)% in the control group (P<0.05) without affecting the GFAP-positive cells.

CONCLUSIONClinically relevant doses of propofol have no obvious effect on the proliferation of rat neural stem cells cultured in vitro, but can induce their differentiation into neuron-like cells.

Animals ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Embryonic Stem Cells ; cytology ; Female ; Neural Stem Cells ; cytology ; Pregnancy ; Propofol ; pharmacology ; Rats ; Rats, Wistar

The objective of this study was to explore the effects of BMP-4 and VEGF on the development of primary hematopoietic stem cells during the differentiation of embryonic stem cells (ESCs) into embryoid body (EB). Murine E14 ESCs were seeded into semisolid methylcellulose-based medium for EB formation. According to added or not cytokines, experiments were divided into: (1) group of spontaneous differentiation without cytokine as control; (2) group of BMP-4 in different concentrations (0, 5, 15, 25 and 50 ng/ml); (3) group of BMP-4 combined with VEGF; (4) group of VEGF alone. EBs were collected on days 3, 6, 9, 12, 15, and the proportion of Flk-1(+) cells were assayed by flow cytometry. The results showed that in the different BMP-4 concentration groups, the proportions of Flk-1(+) cells were significantly different, and it reached the peak values in 25 ng/ml BMP-4 group as 6.51 +/- 1.02% at day 3 and 7.70 +/- 1.12% at day 6 respectively, which were statistically higher than those in control group without-BMP-4 and in 5 ng/ml BMP-4 group (p < 0.05). When BMP-4 was used in combination with VEGF, Flk-1(+) cells went to peak proportion value at day 9 as 27.53 +/- 8.14%, which was statistically higher than that in spontaneous differentiation group as 8.77 +/- 2.35% (p < 0.05) and VEGF treatment group as 11.21 +/- 2.23% (p < 0.05). It is concluded that BMP-4 in combination with VEGF can promote Flk-1(+) cells genesis during EB formation in vitro, which provides experimental evidence for researches on directed differentiation of ESCs into hematopoietic stem cells simulating the microenvironment in vivo.
Animals ; Bone Morphogenetic Protein 4 ; pharmacology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Embryonic Stem Cells ; cytology ; drug effects ; Hematopoietic Stem Cells ; cytology ; Mice ; Vascular Endothelial Growth Factors ; pharmacology

Hypoxia in bone marrow is suitable for the perfect preservation of biological functions of bone marrow hematopoietic stem cells (BM HSC). It is deserved to study whether the biological functions of BM HSC are influenced when being exposed to environment of oxygen at various concentration during amplification of BM HSCs in normal oxygen condition in vitro and process of peripheral blood hematopoietic stem cell transplantation (PBSCT). This study was purposed to investigate the effects of various oxygen concentrations on biological functions of human BM HSCs. The BM HSCs were amplified in vitro, the amplification level of CD34(+) HSCs and CD34(+)AC133(+) HSCs were detected by flow cytometry, the apoptosis and cell cycle distribution of CD34(+) HSCs amplified in various oxygen concentrations were assayed by flow cytometry with Annexin V/PI double staining as well as PI and Ki-67 antibody, respectively, the differentiation of amplified CD34(+) HSCs in vitro was determined by direction differentiation assay, the migration ability of amplified CD34(+)AC133(+) HSCs was measured by migration test. The results indicated that the oxygen environment below normal oxygen, especially hypoxia, could amplify more primitive CD34(+)AC133(+) HSCs and CD34(+) HSCs with activity, arrest more HSCs in G₀/G₁ phase, promote the generation of BFU-E, CFU-GM, CFU-GEMM, and better preserve the migration ability of HSCs. While the above functional indicators of BM HSCs were poor when HSCs exposed to normoxia, oxygen-unstable and oxygen-severe changeable environments. It is concluded that the biological functions of BM HSCs in PBSCT are related with oxygen concentration and its stability, the culture of BM HSCs in lower oxygen environment may be more beneficial for PBSCT.
Bone Marrow Cells ; cytology ; drug effects ; Bone Marrow Transplantation ; Cell Hypoxia ; Cells, Cultured ; Hematopoietic Stem Cell Transplantation ; Hematopoietic Stem Cells ; cytology ; drug effects ; Humans ; Oxygen ; administration & dosage ; pharmacology

OBJECTIVEEmbryonic stem cells (ESCs) are derived from totipotent cells of early embryo and they are potential to differentiate to any kind of cells of tissues in the body. Some reports showed that ESCs had broad capabilities of differentiating to variety of hematopotietic cells, such as erythroid, granulocyte/macrophage, megakaryocyte, mast and lymphocyte precursors. However, it is very difficult to control the phase of differentiation for ESCs in vitro. There is few report about hematopotietic stem cells (HSCs) from ESCs. Therefore, this research was designed to establish a culture system for generation of CD(34)(+)/Sca-1(+) HSC from ESC in vitro.

METHODSSingle mouse E 14.1 cells were suspended in methylcellulose medium, containing 40 ng/ml stem cell factor (SCF) and 20 ng/ml vascular endothelial growth factor (VEGF) and incubated at 37 degrees C with 5% CO2. In order to ensure the viability of the primary differentiation cultures over an extended period of time, the cultures were fed on day 7 with a dilute methylcellulose medium containing VEGF, SCF, interleukin-3 (IL-3), IL-6 and erythropoietin (EPO), which promoted their primary differentiation into embryoid bodies (EBs) with more CD(34)(+)/Sca-1(+) cells. Then, EBs with peak level of CD(34)(+)/Sca-1(+) cells were dispersed into single cells and replanted either in methylcellulose medium or in bone marrow stromal cells differentiation system containing 15% fetal bovine serum (FBS), 160 ng/ml SCF, 20 ng/ml VEGF, 30 ng/ml IL-3, 30 ng/ml IL-6, 3 U/ml EPO and 20% BIT for HSC into second-step differentiation. The HSCs were characterized by flow cytometric analysis, colonogenic cell assay and Wright-Giemsa stains.

RESULTSVEGF had the strongest stimulatory effect on the enhancement of the CD(34)(+)/Sca-1(+) cells population when combined with SCF, IL-3, IL-6 and EPO. It could markedly accelerate mouse E14.1 cells to differentiate into EB with more CD(34)(+)/Sca-1(+) cells. Cell cytometric analysis showed CD(34)(+)/Sca-1(+) cells were up to (1.91 +/- 0.40)% by day 5 and (8.11 +/- 1.17)% by day 8, and the peak level of CD(34)(+)/Sca-1(+) cells was (13.72 +/- 1.92)% by day 12. However, CD(34)(+)/Sca-1(+) cells could not increase in number with the prolongation of differentiation. So renewal single cells suspension from EB by day 12 was dispersed into the second step differentiation. The results showed that HSC was slowly generated with a few hematopoietic colony formations in methylcellulose medium differentiation system. CD(34)(+)/Sca-1(+) cells got (2.74 +/- 0.80)% by day 5 and (11.37 +/- 1.84)% by day 10, and apex percentage of CD(34)(+)/Sca-1(+) cells was about (20.52 +/- 2.78)% by day 14. However, EBs generated quickly for HSC with increased hematopoietic cell population by co-culture on bone marrow stromal cells feeder. Flow cytometric analysis showed that the percentages of CD(34)(+)/Sca-1(+) cells was (7.33 +/- 1.61)% by day 5, (13.28 +/- 2.59)% by day 8, and (20.81 +/- 3.19)% by day 10. EB cells were induced after 12 days to reach the peak level of (34.60 +/- 3.71)%. Hematopoietic colony formation unit (CFU) analysis showed that CFU was sufficient from cells on bone marrow stromal cells differentiation system in the second step compared to that in methylcellulose medium differentiation system, and Wright-Giemsa stain could confirm its characteristics of hematopoietic progenitors.

CONCLUSIONUsing two-step differentiation, the investigators got a good way to control the phase of differentiation from ESC to HSC. The bone marrow stromal cell differentiation system combining with VEGF, SCF, IL-3, IL-6 and EPO was an optimal system for the generation of HSC with CD(34)(+)/Sca-1(+) surface marker from ESC differentiated in vitro. This study demonstrated that these cells could form more hemopoietic colonies.

Animals ; Antigens, CD34 ; Cell Culture Techniques ; Cell Differentiation ; drug effects ; Cell Survival ; Cells, Cultured ; Embryonic Stem Cells ; drug effects ; immunology ; Hematopoietic Stem Cells ; physiology ; Mice

This study was aimed to investigate the effect of 1,4-benzoquinone (1,4-BQ) on growth of myeloid progenitor cells with IFN-gamma different genotypes and to compare its differences. Polymerase chain reaction (PCR) was used to amplify the polymorphism gene segment of IFN-gamma +874 A/T in 36 cord blood (CB) specimens. The specimens were divided into three groups (AA, AT and TT group). MNCs were planted on complete methylcellulose medium containing different concentrations of 1,4-BQ. The colony-forming units (CFU) were assayed, the differences of colony growth in specimens with different genotypes (AA, AT and TT) under 1,4-BQ exposure were analyzed. The results showed that frequencies of AA, AT and TT genotypes were 5.56%, 88.89% and 5.56% in the 36 CB samples respectively. Comparing colony numbers of IFN-gamma +874 AA, AT and TT genotype indicated that there was significant difference (p(AA) = 0.033, p(AT) = 0.009, p(TT) = 0.001, < 0.05). Significant cytotoxicity was observed after exposure to concentrations of 1,4-BQ > or = 5 micromol/L. Cytotoxic response of 1,4-BQ was dose-dependent. Under the same concentration of 1,4-BQ, there were no significant differences in capacity of cell colony growth between 3 groups (AA, AT and TT). Colony numbers of specimen No 3 in AT group and specimen No 2 in TT group were less than those of other specimens significantly. It is concluded that the hematopoietic myeloid progenitor cells cultured in the presence of 1,4-BQ show a dose-dependent cytotoxic response, but there are no significant differences in colony growth of IFN-gamma different genotypes (AA, AT and TT) under the same concentration of 1,4-BQ.
Benzoquinones ; pharmacology ; Bone Marrow Cells ; drug effects ; Fetal Blood ; cytology ; Genotype ; Hematopoietic Stem Cells ; drug effects ; Humans ; Interferon-gamma ; genetics ; Stem Cells

BACKGROUNDPrevious studies have shown that resveratrol increases endothelial progenitor cell (EPC) numbers and functional activity. Increased EPC numbers and activity are associated with the inhibition of EPC senescence. In this study, we investigated the effect of resveratrol on the senescence of EPCs, leading to potentiation of cellular function.

METHODSEPCs were isolated from human peripheral blood and identified immunocytochemically. EPCs were incubated with resveratrol (1, 10, and 50 µmol/L) or control for specified times. After in vitro cultivation, acidic β-galactosidase staining revealed the extent of senescence in the cells. To gain further insight into the underlying mechanism of the effect of resveratrol, we measured telomerase activity using a polymerase chain reaction (PCR)-enzyme-linked immunosorbent assay (ELISA) technique. Furthermore, we measured the expression of human telomerase reverse transcriptase (hTERT) and the phosphorylation of Akt by immunoblotting.

RESULTSResveratrol dose-dependently inhibited the onset of EPC senescence in culture. Resveratrol also significantly increased telomerase activity. Interestingly, quantitative real-time PCR analysis demonstrated that resveratrol dose-dependently increased the expression of the catalytic subunit, hTERT, an effect that was significantly inhibited by pharmacological phosphatidylinositol 3-kinase (PI3-K) blockers (wortmannin). The expression of hTERT is regulated by the PI3-K/Akt pathway; therefore, we examined the effect of resveratrol on Akt activity in EPCs. Immunoblotting analysis revealed that resveratrol led to dose-dependent phosphorylation and activation of Akt in EPCs.

CONCLUSIONResveratrol delayed EPCs senescence in vitro, which may be dependent on telomerase activation.

Cells, Cultured ; Cellular Senescence ; drug effects ; Endothelial Cells ; cytology ; drug effects ; enzymology ; Humans ; Stem Cells ; cytology ; drug effects ; enzymology ; Stilbenes ; toxicity ; Telomerase ; metabolism