The use of GABA(A) receptors expressed in neural precursor cells for cell-based assays

Glial‐derived nexin, a differentially expressed gene during neuronal differentiation, transforms HEK cells into neuron‐like cells

Glial-derived nexin (GDN) is a proteinase inhibitor secreted from glial cells and it can enhance neuronal function. However, its expression and function in neuronal differentiation are not, as yet, well-known. In the present study, we analyzed glial-derived nexin gene expression in dissociated neural stem/progenitor cells (NS/PCs) (D0) from the embryonic mouse cerebral cortex, expanded NS/PC cultures (D4 and D10 cultures) and cultured neurons (E15) using a semi-quantitative RT-PCR assay. Our data suggest that mouse GDN, homologue of human GDN, was significantly up-regulated in the expanded NS/PC cultures and cultured neurons. To analyze its function in neuronal differentiation, human GDN cDNA was cloned into bicistronic plasmids containing green fluorescent protein (GFP) and the resulting plasmids were transfected into rodent primary NS/PCs and non-neuronal human embryonic kidney (HEK) cells. Our data suggest that the ectopic expression of human GDN triggered the expression of the neuronal marker TuJ1 in both NS/PCs and HEK cells. We conclude that GDN is up-regulated during neuronal differentiation and plays a role in transforming non-neuronal HEK cells into neuron-like cells.

AF1q, a differentially expressed gene during neuronal differentiation, transforms HEK cells into neuron-like cells

Three cell groups, neural stem/progenitor cells (NS/PCs) dissociated from the embryonic day 11 (E11) rodent cerebral cortex, expanded NS/PC cultures, and cultured neurons from E15, were used to conduct a genomic study with differential display (DD). The mouse Af1q, homologue of human AF1q, was found to be significantly up-regulated during the neuronal production from NS/PCs. The ectopic expression of human AF1q triggered the expression of the neuronal marker TuJ1 in non-neuronal human embryonic kidney (HEK) cells.

Characterization of H2O2-induced acute apoptosis in cultured neural stem/progenitor cells

In the present study, we characterized hydrogen peroxide (H2O2)-induced cell apoptosis and related cell signaling pathways in cultured embryonic neural stem/progenitor cells (NS/PCs). Our data indicated that H2O2 induced acute cell apoptosis in NS/PC in concentration- and time-dependent manners and selectively, it transiently increased PI3K-Akt and Mek-Erk1/2 in a dose-dependent manner. Inhibition of PI3K-Akt with wortmannin, a PI3-K inhibitor, was found to significantly increase H2O2-induced acute apoptosis and dramatically decrease basal pGSK3beta levels. The level of pGSK3beta remained unchanged with H2O2 exposure. We conclude that the transient activation of PI3K-Akt signaling delays the H2O2-induced acute apoptosis in cultured NS/PCs in part through maintaining the basal pGSK3beta level and activating other downstream effectors.

Assessing the feasibility of using neural precursor cells and peripheral blood mononuclear cells for detection of bioactive Sindbis virus

Viruses form a significant class of bio-threat agents. Currently, the only method to determine the bioactivity of viruses in vitro is to measure viral and cellular responses after co-incubation of cells with virus. Our goal is to find biomarkers for classification of agents, establishment of bioactivity, and/or prediction of disease outcomes. To begin development of a cell-based biosensor for detection of bioactive Sindbis virus (SV), our model analyte, we surveyed the outcomes of SV interaction with primary rat neural precursor cells (NPC) and human peripheral blood mononuclear cells (PBMC). Confocal fluorescence analysis of NPC treated with recombinant SV carrying green-fluorescent-protein (SV-GFP) showed that most cells were GFP positive by day 1 post inoculation. 4',6-Diamidino-2-phenylindole dihydrochloride (DAPI) staining of the nucleus showed nuclear condensation and fragmentation, and the percentage of TUNEL positive cells were higher in virus-treated cells than in mock-treated control. Also, there were less BrdU positive cells in virus-treated cells compared to control. Thus, SV infects NPC, decreases cellular proliferation, and induces cell death via apoptosis. PBMC were treated with SV- or UV-inactivated SV. By day 5 post infection, there were fewer adherent cells in SV-treated PBMC compared to UV-inactivated SV treated PBMC. However, the percentage of viable cells remained the same, and virus growth curves showed only clearance of virus. Thus, SV induces detachment of a subpopulation of PBMC while not killing most of the cells. Together, these results indicate that NPC and PBMC respond to bioactive SV inoculation, suggesting potential use as detectors of SV in cell-based biosensor paradigm. These studies also provide the rationale, time-scale, and phenotypic correlates for further studies with gene expression arrays.