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Wei Bian

Publications and source records attributed to Wei Bian.

13 recordsLinked to original sources
PubMed2006

Cell aggregation-induced FGF8 elevation is essential for P19 cell neural differentiation.

FGF8, a member of the fibroblast growth factor (FGF) family, has been shown to play important roles in different developing systems. Mouse embryonic carcinoma P19 cells could be induced by retinoic acid (RA) to differentiate into neuroectodermal cell lineages, and this process is cell aggregation dependent. In this report, we show that FGF8 expression is transiently up-regulated upon P19 cell aggregation, and the aggregation-dependent FGF8 elevation is pluripotent stem cell related. Overexpressing FGF8 promotes RA-induced monolayer P19 cell neural differentiation. Inhibition of FGF8 expression by RNA interference or blocking FGF signaling by the FGF receptor inhibitor, SU5402, attenuates neural differentiation of the P19 cell. Blocking the bone morphogenetic protein (BMP) pathway by overexpressing Smad6 in P19 cells, we also show that FGF signaling plays a BMP inhibition-independent role in P19 cell neural differentiation.

Animals↗
PubMed2006

Development and validation of pheochromocytoma of the adrenal gland scaled score for predicting malignant pheochromocytomas.

OBJECTIVES: To evaluate the diagnostic performances of the pheochromocytoma of the adrenal gland scaled score (PASS) proposed in a previous report and that of a logistic model developed in this investigation. METHODS: In all 130 patients with malignant or assumed benign pheochromocytomas, 15 predictive variables were observed. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of PASS. The logistic model was developed using the 15 predictive variables. Its performance was evaluated by calculating the area under the ROC curve and comparing it with that of the PASS. RESULTS: The PASS had the area under the ROC curve of 0.899 (95% confidence interval 0.844 to 0.954). Of the 15 variables entered in the logistic regression analysis, 9 were retained in the model. The area under the ROC curve for the logistic model was 0.983 (95% confidence interval 0.967 to 0.998). CONCLUSIONS: ROC analysis indicated that the PASS could be used for the diagnosis of malignant pheochromocytomas. The logistic model was able to improve the diagnostic performance of the PASS using a different variable weighting method. We emphasize, however, that a clinical prospective evaluation is needed to confirm their actual value.

Adrenal Gland Neoplasms↗
PubMed2006

Visualization of bHLH transcription factor interactions in living mammalian cell nuclei and developing chicken neural tube by FRET.

Members of the basic helix-loop-helix (bHLH) gene family play important roles in vertebrate neurogenesis. In this study, confocal microscopy-based fluorescence resonance energy transfer (FRET) is used to monitor bHLH protein-protein interactions under various physiological conditions. Tissue-specific bHLH activators, NeuroD1, Mash1, Neurogenin1 (Ngn1), Neurogenin2 (Ngn2), and ubiquitous expressed E47 protein are tagged with enhanced yellow fluorescence protein (EYFP) and enhanced cyan fluorescence protein (ECFP), respectively. The subcellular localization and mobility of bHLH fusion proteins are examined in HEK293 cells. By transient transfection and in ovo electroporation, four pairs of tissue-specific bHLH activators and E47 protein are over-expressed in HEK293 cells and developing chick embryo neural tube. With the acceptor photobleaching method, FRET could be detected between these bHLH protein pairs in the nuclei of transfected cells and developing neural tubes. Mash1/E47 and Ngn2/E47 FRET pairs show higher FRET efficiencies in the medial and the lateral half of chick embryo neural tube, respectively. It suggests that these bHLH protein pairs formed functional DNA-protein complexes with regulatory elements of their downstream target genes in the specific regions. This work will help one understand the behaviours of bHLH factors in vivo.

Animals↗
PubMed2006

Second intron of mouse nestin gene directs its expression in pluripotent embryonic carcinoma cells through POU factor binding site.

Nestin, an intermediate filament protein, is expressed in the neural stem cells of the developing central nervous system. This tissue-specific expression is driven by the neural stem cell-specific enhancer in the second intron of the nestin gene. In this study, we showed that the mouse nestin gene was expressed in pluripotent embryonic carcinoma (EC) P19 and F9 cells, not in the differentiated cell types. This cell type-specific expression was conferred by the enhancer in the second intron. Mutation of the conserved POU factor-binding site in the enhancer abolished the reporter gene expression in EC cells. Oct4, a Class V POU factor, was found to be coexpressed with nestin in EC cells. Electrophoretic mobility-shift assays and supershift assays showed that a unique protein-DNA complex was formed specifically with nuclear extracts of EC cells, and Oct4 protein was included. Together, these results suggest the functional relevance between the conserved POU factor-binding site and the expression of the nestin gene in pluripotent EC cells.

Animals↗
PubMed2006

[Study on the interaction of tetrabromofluorescein and DNA].

The interaction of tetrabramofluorescein (TBF) and DNA was studied by the fluorescence and SS-RTP. The effect of the ion strength and ethanol on the fluorescence spectra of TBF in the presence of DNA and absence of DNA was investigated. In addition, the effect of pH on the SS-RTP spectra of TBF was also examined. The quenched constant was 719.74 and 880.22 in the absence and presence of DNA respectively. Finally, the interaction mode between TBF and DNA was discussed from the fluorescence quenched and phosphorescence polarized experiments.

Animals↗
PubMed2006

[Study on interaction of caffeine and theophylline with bovine serum albumins].

The interation of caffeine and theophylline with bovine serum albumins has been studied by fluorescence spectroscopy. The results indicated that enoxacin could bind with BSA strongly at molar ratio 1:1 and the equilibrium constants were Kc = 1.673 x 10(4) L x mol(-1) and Kt = 6.802 x 10(3) L x mol(-1), respectively. Good linear Stern-Volmer lines were observed on the fluorescence of BSA quenched by enoxacin of different concentration, indicating that the combination reaction of enoxacin with BSA is a single static quenching process.

Animals↗
PubMed2005

The LIM/homeodomain protein Islet1 recruits Janus tyrosine kinases and signal transducer and activator of transcription 3 and stimulates their activities.

Islet1 (Isl1) belongs to the LIM homeodomain transcription factor family. Its roles in differentiation of motor neurons and organogenesis of pancreas and heart have been revealed. However, less is known about its regulatory mechanism and the target genes. In this study, we identified interactions between Isl1 and Janus tyrosine kinase (JAK), as well as signal transducer and activator of transcription (Stat)3, but not Stat1 and Stat5, in mammalian cells. We found that Isl1 not only forms a complex with Jak1 and Stat3 but also triggers the tyrosine phosphorylation of Jak1 and its kinase activity, thereby elevating the tyrosine phosphorylation, DNA binding activity, and target gene expression of Stat3. In vivo, the tyrosine-phosphorylated Stat3 was colocalized with Isl1 in the nucleus of the mouse motor neurons in spinal cord after nerve injury. Correspondingly, electroporation of Isl1 and Stat3 into the neural tube of chick embryos resulted in the activation of a reporter gene expression controlled by a Stat3 regulatory sequence, and cotransfection of Isl1 and Stat3 promoted the proliferation of the mouse motor neuron cells. Our data suggest a novel role of Isl1 as an adaptor for Jak1 and Stat3 and reveal a possible functional link between LIM homeodomain transcription factors and the Jak-Stat pathway.

Animals↗
PubMed2004

Stat3 signaling is present and active during development of the central nervous system and eye of vertebrates.

Stat3, a member of the signal transducer and activator of transcription (STAT) family, plays a central role in mediating cell growth, differentiation, and survival signals. In this report, we show that Stat3 immunoreactivity was localized to specific regions in the developing mouse brain, neural tube, and eye from embryonic day 10.5 to postnatal day 0. The active form of Stat3 protein, which is phosphorylated on tyrosine 705 (pYStat3), was also found in the developing neural tube with more restricted distribution. An in ovo chick embryo electroporation assay showed that the endogenous chick Stat3 could drive consensus sis-inducible element-directed reporter gene expression. These results demonstrate that the active Stat3 protein is present and might play a role during the development of the central nervous system and eye.

Animals↗
PubMed2004

SNAP-25 in hippocampal CA1 region is involved in memory consolidation.

As a synaptosomal protein, SNAP-25 plays a role in a number of neuronal functions including axonal growth, dendrite formation, fusion of synaptic vesicles with membrane and the expression of long-term potentiation (LTP) in the hippocampus. Using a learning/memory behavior screening, we identified SNAP-25 as one of the differentially expressed genes in the hippocampus upon behavioral training. The inhibition of SNAP-25 with intracerebroventricular antisense oligonucleotide caused a deficit in long- but not short-term memory for step-down inhibitory avoidance. Intra-CA1 infusion of the SNAP-25 antisense oligonucleotide impaired long-term contextual fear memory and spatial memory and interfered with the LTP of synaptic transmission in the CA1 region. The inhibitory effect on LTP was not mediated by a pre-synaptic mechanism because paired pulse facilitation of synaptic transmission was not affected after administration of the antisense oligonucleotide. Together, the results suggest that SNAP-25 in the CA1 region is involved in memory consolidation.

Animals↗
PubMed2002

Localization of CCTbeta in rat brain and overexpression in insect cells.

AIM: To study the localization of CTP: phosphocholine cytidylyltransferase beta isoform (CCTbeta) in rat brain, its expression in insect cells and enzymatic properties. METHODS: Using digoxigenin-labeled CCTbeta probes, in situ hybridization was carried out in rat brain wax sections. CCTbeta was overexpressed in Trichoplusia Ni (Tn) cells using baculovirus expression system. CTP:phosphocholine cytidylyltransferase assay (CT assay) and [3H] metabolic labeling experiment were used to study its activity, properties, and the effect on phosphatidylcholine (PC) synthesis. RESULTS: (1) CCbeta was abundant in CA1, CA2, CA4, and dentate gyrus (DG) region of hippocampus. (2) The content of CCTbeta in transfected Tn cells was over 1 104 times of that in rat brain, and CCTbeta increased the PC synthesis of Tn cells. (3) Hexadecylphosphocholine as well as some ions like Zn2+ and PO3-4 could inhibit the activity of CCTbeta, dCTP was another adaptive substrate of CCTbeta besides CTP. CONCLUSION: CCTbeta showed a similar localization in rat brain with the memory enhancing peptide argipressin (4-8).

Animals↗
PubMed1999

N-cadherin Invovles in P19 Cell in vitro Neuronal Differentiation.

N-cadherin plays an important role in the early morphogenesis of neural tissue. For exploring the possible role of N-cadherin in neuronal differentiation in vitro, we chose RA induced P19 cell neuronal differentiation as a model system. Using RT-PCR, we examined the expression pattern of N-cadherin during P19 cell neuronal differentiation. The results showed that N-cadherin expression was increased rapidly during RA induction with its highest expression level at day 3 of neuronal differentiation, then down-regulated along with neuronal maturation. This expression pattern was similar with CNS development in vivo. Then, we constructed a N-cadherin expression-vector and transfected in P19 cells. The stable transfected cell lines, N-cadherin/P19 were selected, and we found that, after aggregated 4 days, the N-cadherin overexpression P19 cells could differentiate into neuron-like cells without the RA induction. The immunocytochemical staining showed that these neuron-like cells expressed neuron specific marker, NF160. These results suggest that N-cadherin gene is involved in P19 neuron differentiation.

Journal Article↗
PubMed1999

In Situ Hybridization of RA Induced P19 Cells.

P19 EC cells can be induced to differentiate into neurons in vitro when they were treated with 1x10(-6) mol/L retinoic acid. In the process of neuronal differentiation, P19 cells gradually migrate and form aggregates. Aggregated cells weakly adhered to the surface of cell culture dishes are usually dropped of during the procedure of in situ hybridization. To keep cells on the coverslips, we modified the procedure by using 1 g/L gelatin solution to cover the cells and substituting proteinase K treatment with pepsin treatment which digested cellular proteins mildly. With the treatment of pepsin, RNA probe can easily go through cell membrane and bind to its target, without loss of cell from coverslips.

Journal Article↗