To study the effect of lysophosphatidic acid (LPA) on the differentiation of embryonic neural stem cells (NSCs) into neuroglial cells in rats in vitro, both oligodendrocytes and astrocytes were detected by their marker proteins galactocerebroside (Gal-C) and glial fibrillary acidic protein (GFAP), respectively, using double-labeling immunocytochemistry. RT-PCR assay was also used for analyzing the expression of LPA receptors in NSCs. Our results showed that: (1) LPA at different concentrations (0.01-3.0 mumol/L) was added to culture medium and cell counting was carried out on the 7th day in all groups. Exposure to LPA led to a dose-dependent increase of oligodendrocytes with the response peaked at 1.0 mumol/L, with an increased percentage of 32.6% (P<0.01) of total cells as compared to that of 8.5% in the vehicle group. (2) LPA showed no effect on the differentiation of NSCs into astrocytes. (3) RT-PCR assay showed that LPA(1) and LPA(3) receptors were strongly expressed while LPA(2) receptor expressed weakly in NSCs. These results suggest that LPA at low concentration might act as an extracellular signal through the receptors in NSCs, mainly LPA(1) and LPA(3) receptors, to promote the differentiation of NSCs into oligodendrocytes, while it exhibits little, if any, conceivable effect on the differentiation of NSCs into astrocytes.
Animals ; Cell Differentiation ; drug effects ; Cells, Cultured ; Lysophospholipids ; pharmacology ; Neural Stem Cells ; cytology ; drug effects ; Neuroglia ; cytology ; Rats ; Receptors, Lysophosphatidic Acid ; metabolism

Human embryonic stem cells (hESCs) are pluripotent cells that have the ability of unlimited self-renewal and can be differentiated into different cell lineages, including neural stem (NS) cells. Diverse regulatory signaling pathways of neural stem cells differentiation have been discovered, and this will be of great benefit to uncover the mechanisms of neuronal differentiation in vivo and in vitro. However, the limitations of hESCs resource along with the religious and ethical concerns impede the progress of ESCs application. Therefore, the induced pluripotent stem cells (iPSCs) via somatic cell reprogramming have opened up another new territory for regenerative medicine. iPSCs now can be derived from a number of lineages of cells, and are able to differentiate into certain cell types, including neurons. Patient-specifi c iPSCs are being used in human neurodegenerative disease modeling and drug screening. Furthermore, with the development of somatic direct reprogramming or lineage reprogramming technique, a more effective approach for regenerative medicine could become a complement for iPSCs.
Cell Differentiation ; Cell Lineage ; Cell Transdifferentiation ; Cellular Reprogramming ; drug effects ; Embryonic Stem Cells ; cytology ; Humans ; Induced Pluripotent Stem Cells ; cytology ; transplantation ; Neural Stem Cells ; cytology ; transplantation ; Neurodegenerative Diseases ; therapy ; Regenerative Medicine ; Transcription Factors ; genetics ; metabolism

OBJECTIVETo screen out main molecular target promoting human neural stem cells (NSCs) of ginsenoside Rg1 by using the gene chip technology.

METHODFirst, MTT assay was adopted to screen out the optimal concentration of Rg1-promoted NSC proliferation (120 mg x L(-1)). Then, on the 7th day after the Rg1-promoted NSC proliferation, the expression of target genes was observed by the gene chip technology. The most important target gene and signal transduction pathways were screened out through the data calculations.

RESULTOn the 7th day after the Rg1-promoted NSC proliferation, obtained 440 differential genes, 266 significantly upregulated genes and 174 significantly down-regulated genes. HES1 gene, CAMP (cyclic adenosine monophosphate)-PKA (protein kinase A) and PI3K (phosphatidylinositol 3 kinase)-AKT signal transduction pathways were closely related to the NSC proliferation.

CONCLUSIONThe differentially expressed genes screened out by gene chip may provide new clues for studies on molecular mechanism of ginsenoside Rg1-promoted NSCs proliferation.

Cell Proliferation ; drug effects ; Ginsenosides ; pharmacology ; Humans ; Neural Stem Cells ; cytology ; drug effects ; metabolism ; Oligonucleotide Array Sequence Analysis ; RNA ; genetics ; isolation & purification

Rat hippocampal precursor cells isolated from hippocampi of embryonic day 16.5 (E16.5) rat embryos were found to proliferate in the presence of basic fibroblast growth factor. Addition of soluble neural cell adhesion molecule (NCAM) to these precursor cells reduced cell proliferation in a dose dependent manner and enhanced the induction of precursor cells' differentiation to the neuronal lineage. Given these findings that NCAM induces the differentiation of hippocampal precursor cells, we investigated possible effects of NCAM on the expression of basic helix-loop-helix (bHLH) transcription factors during the differentiation. Soluble NCAM upregulated the transcription of bHLH transcription factors, neurogenin1 and NeuroD, but decreased HES5. Western blot analysis showed that NCAM increased the expression levels of CaMKII, p-MAPK, GluR1 and NR1 but decreased p-STAT3. These results support a role for NCAM in the inhibition of proliferation and the induction of neural differentiation of hippocampal neural precursor cells, and act as developmental regulators of the bHLH families, ultimately leading to the generation of glutamatergic neural cell types in the differentiation of hippocampal precursor cells.
Animals ; Apoptosis/drug effects ; Cell Differentiation/*drug effects ; Cell Division/drug effects ; Cell Lineage/drug effects ; Cells, Cultured ; Helix-Loop-Helix Motifs ; Hippocampus/*cytology/*drug effects ; Neural Cell Adhesion Molecules/*pharmacology ; Neurons/cytology/*drug effects/metabolism ; RNA, Messenger/genetics/metabolism ; Rats ; Receptors, Glutamate/*metabolism ; Signal Transduction ; Stem Cells/cytology/*drug effects ; Transcription Factors/genetics/metabolism

OBJECTIVETo investigate effects of paraquat on the mRNA expression of key elements of Notch signaling (Notch1, Jagged1 and DTX1) during differentiation process of human neural stem cells (hNSCs).

METHODShNSCs exposed to PQ at the concentrations 0.10, 1.00, 10.00 M. Cell proliferation ability was assessed using MTT assay and mRNA expressions of Notch1, Jagged1 and DTX1 were detected by Real-time RT-PCR at 2, 4, 8, 12 d of differentiation.

RESULTSCompared with control group, NOTCH1, JAG1 mRNA expression levels exposed to PQ at the concentration of 0.10 M significantly reduced at 2, 4, 8 d and significantly went up at 12d (P < 0.01). Compared with control group, NOTCH1, JAG1 and DTX1 mRNA expression levels exposed to PQ at the concentration of 10.00 M significantly reduced at 2, 8, 12 d (P < 0.01). PQ could down-regulate Notch1, Jagged1 and DTX1 mRNA expressions at the early stage of differentiation, then up-regulate Notch1 mRNA expression, and down-regulate Notch1, Jagged1 and DTX1 mRNA expressions at the end of differentiation.

CONCLUSIONNotch signaling pathway may be involved in differentiation of neural stem cell exposed to PQ.

Calcium-Binding Proteins ; metabolism ; Cell Differentiation ; drug effects ; Cells, Cultured ; Embryonic Stem Cells ; cytology ; drug effects ; metabolism ; Humans ; Intercellular Signaling Peptides and Proteins ; metabolism ; Jagged-1 Protein ; Membrane Proteins ; metabolism ; Neural Stem Cells ; cytology ; drug effects ; metabolism ; Paraquat ; pharmacology ; Receptor, Notch1 ; metabolism ; Serrate-Jagged Proteins ; Signal Transduction ; drug effects ; Ubiquitin-Protein Ligases ; metabolism

OBJECTIVETo observe the effects of ginsenoside Rg1 on the functional expression of human neural stem cells (hNSCs).

METHODThe membrane electrophysiological properties and sodium and potassium ion channels in the hNSCs induced by Rg1 were analyzed using the whole-cell patch-clamp.

RESULTOn the 7th day, the neuron-like cells derived from ginsenoside Rg1 (20 mg x L(-1))-induced NSCs show: (1) The resting membrane potential: (-45.70 +/- 2.63) mV, the membrane capacitance: (26.89 +/- 1.91) pF, the membrane input impedance: (877.51 +/- 20.44) MH (P < 0.05 compared with the control group, respectively); (2) The detection rate of inward sodium current which is rapidly activated and inactivated in voltage-dependence was 50%, and its average peak value was (711.48 +/- 158.03) pA (P < 0.05 compared with the control group); (3) The outward potassium currents were composed of rapidly activated and inactivated transient outward potassium current and delayed rectifier outward potassium current, and its average peak value was (1 070.42 +/- 177.18) pA (P < 0.05 compared with the control group).

CONCLUSIONGinsenoside Rg1 can promote the functional expression and maturity of hNSCs.

Cells, Cultured ; Gene Expression ; drug effects ; Ginsenosides ; pharmacology ; Humans ; Membrane Potentials ; drug effects ; Neural Stem Cells ; cytology ; drug effects ; Patch-Clamp Techniques ; Plant Extracts ; pharmacology ; Potassium Channels ; genetics ; metabolism ; Sodium Channels ; genetics ; metabolism

OBJECTIVEThe molecular targets of ginsenoside Rg1-induced neural stem cells (NSCs) differentiation were screened by genechip.

METHOD7th day following ginsenoside Rg1 induced human neural stem cells to neurons the gene expression was observed by genechip. The purpose gene and signal transduction pathways were selected by the data calculations, and then confirmed by western blot and immunohistochemical method.

RESULT7th day following Rg1-induced NSCs differentiation, there were about 675 different genes, 255 genes of which were up-regulated and 420 genes down-regulated obviously. Meanwhile the ERK1/2 (extracellular signal-regulated protein kinase) in MAPK (mitogen-activated protein kinase) pathway was related with the NSCs differentiation. The Western blot and immunohistochemistry detection confirmed that ERK 1/2 protein and its phosphorylation were significantly increased, which can be blocked by PD98059 (ERK1/2 inhibitor). In addition, differentiation rate of NSCs was also decreased obviously in ginsenoside Rg1-induced differentiated NSCs when ERK blocker PD98059 was used.

CONCLUSIONERK1/2 is an important molecular target in ginsenoside Rg1-induced NSC differentiation. The selected differentially expressed genes by genechip may provide new clues to study of ginsenoside Rg1-induced NSCs differentiation.

Cell Differentiation ; drug effects ; Cell Line ; Down-Regulation ; drug effects ; Flavonoids ; pharmacology ; Ginsenosides ; pharmacology ; Humans ; MAP Kinase Signaling System ; drug effects ; genetics ; Neural Stem Cells ; cytology ; drug effects ; metabolism ; Oligonucleotide Array Sequence Analysis ; Protein Kinase Inhibitors ; pharmacology ; Time Factors

The amphiphilic polypeptide (PA) was self-assembled into three-dimensional (3-D) porous complex of hydrogel and cells with the addition of NSCs-containing DMEM/F12. Cell differentiation in the surface and that within hydrogel were described. Cells harvested from the cerebral cortex of neonatal mice were triturated and cultivated in serum-free media. 1wt% PA was added into same volume of DMEM/F12 with cell concentration of 1 x 10(5)/ml and self-supported into 3-D hydrogel-cell composition; cells suspended within hydrogel being maintained (Experiment group, EG). lwt% PA was self-assembled into two-dimensional (2-D) hydrogel films triggered by addition of DMEM/F12, and then 1 x 10(5)/ml NSCs was seeded in the surface of films (Control group, CG). Cells in EG and CG were incubated in serum-free media for two weeks and stained with immunocytochemistry methods. TEM showed that the hydrogel derived from PA was composed of network nanofibers with their diameter ranging from 3 to 5 nm and length ranging from 100 nm to 1. 5 microm. Above 50% of cells obtained were Nestin positive cells. LSCM observations demonstrated that above 90% of cells survived two days after incubation within hydrogel, and were differentiated into NF and GFAP positive cells one week after incubation, their differentiation rates were 50% +/- 4.2% and 20% +/- 2.8% respectively; however, cells in CG were also differentiated into NF and GFAP positive cells, their differentiation rates were only 40% +/- 3.4% and 31% +/- 2.3% separately. Peptide-based hydrogel was able to provide 3-D environments for cell survival and induce primarily the differentiation of NSCs into neurons. Our data indicated that peptide-directed self-assembly of hydrogels was useful and it served as the neotype nerve tissue engineering scaffolds.
Animals ; Animals, Newborn ; Cell Culture Techniques ; Cell Differentiation ; drug effects ; Cells, Cultured ; Hydrogel, Polyethylene Glycol Dimethacrylate ; chemistry ; metabolism ; Nanofibers ; chemistry ; Neural Stem Cells ; cytology ; Neurogenesis ; drug effects ; Peptides ; chemistry ; metabolism ; Rats ; Rats, Sprague-Dawley ; Tissue Scaffolds ; chemistry

BACKGROUNDReplacement of spiral ganglion neurons would be one prioritized step in an attempt to restore sensory neuronal hearing loss. However, the possibility that transplanted neurons could regenerate new synaptic connections to hair cells has not been explored. The objective of this study was to test whether neural stem cell (NSC)-derived neurons can form synaptic connections with hair cells in vitro.

METHODSNSCs were mechanically separated from the hippocampus in SD rat embryos (E12-E14) and cultured in a serum-free medium containing basic fibroblast growth factor and epidermal growth factor. Rat NSCs were co-cultured with explants of cochlea sensory epithelia obtained from postnatal Day 3 rats under transway filter membrane.

RESULTSAt Day 3, the NSCs began to show chemotactic differentiation and grew toward cochlea sensory epithelia. After 9-day co-culture, neurites of NSC-derived neurons predominantly elongated toward hair cells. Immunohistochemical analyses revealed the fibers overlapped with synapsin and hair cells, indicating the formation of new synaptic connections. After 14-day culture, triple staining revealed the fibers overlapped with PSD95 (postsynaptic density) which is juxtaposed with CtBP2 (presynaptic vesicle), indicating the formation of new ribbon synapse.

CONCLUSIONSNSC-derived neurons can make synaptic connections with hair cells and provide a model for studying synaptic plasticity and regeneration. Whether the newly forming synapse is functional merits further electrophysiological study.

Animals ; Cell Differentiation ; drug effects ; Cells, Cultured ; Coculture Techniques ; Epidermal Growth Factor ; pharmacology ; Fibroblast Growth Factor 2 ; pharmacology ; Hair Cells, Auditory ; cytology ; drug effects ; ultrastructure ; Neural Stem Cells ; cytology ; drug effects ; ultrastructure ; Neurons ; cytology ; drug effects ; ultrastructure ; Rats ; Rats, Sprague-Dawley ; Synapses ; drug effects ; metabolism

It has been shown that neural cell adhesion molecule (NCAM)-induced neuronal differentiation is extracellular signal-regulated kinase (ERK)-dependent. However, an involvement of the mitogen activated protein kinase (MAPK) kinase (MEK), an upstream kinase of ERK, has not been directly demonstrated in this process. Therefore, we investigated whether the MEK1 plays a critical role in the NCAM-induced neuronal differentiation of hippocampal neural progenitor cells (NPCs). NPCs were transiently transfected with expression plasmids encoding activated or dominant negative (DN) forms of MEK1. The expression of DN MEK1 inhibited neuronal phenotype acquisition and soluble NCAM rescued the defect in the neuronal phenotype acquisition in DN-MEK1-transfected cells, suggesting that NCAM might contribute to the neuronal differentiation via distinct, parallel pathways including the MEK pathway. In cells expressing wild type MEK1 or constitutively active MEK1 on the other hand, the percentage of cells positive for beta-tubulin type III (Tuj1), a marker for early postmitotic neurons, was higher than seen in vector-transfected cells. These results suggest that the activation of MEK1 is required for obtaining neuronal phenotype in NPCs.
Transfection ; Stem Cells/cytology/drug effects/*metabolism ; Solubility ; Rats ; *Phenotype ; Neurons/cytology/drug effects/*metabolism ; Neural Cell Adhesion Molecules/*pharmacology ; Mutation/genetics ; MAP Kinase Kinase 1/genetics/*metabolism ; Hippocampus/cytology/drug effects/*metabolism ; Gene Expression Regulation ; Cells, Cultured ; Cell Differentiation ; Animals