Entity

Time filter

Source Type


Nie H.-Z.,Shanghai JiaoTong University | Li Z.-Q.,Key Laboratory of Cell Differentiation and Apoptosis | Yan Q.-X.,Shenzhen Neptunus Bioengineering Holdings Co. | Wang Z.-J.,Shanghai JiaoTong University | And 3 more authors.
Neurochemical Research | Year: 2011

Alzheimer's disease (AD) is a neurodegenerative disorder that affects the elderly population. Deposition of beta-amyloid (Aβ) in the brain is a hallmark of AD pathology. In our previous study, we have constructed a cell line expressing human APP695 (hAPP695) in SH-EP1 cells stably transfected with human nicotinic receptor (nAChR) α4 subunit and β2 subunit gene. In present study, we found that activation of α4β2 nAChR by nicotine and epibatidine decreased secreted Aβ level in the cell line and hippocampal neurons, but had no effects on full-length APP695 and sAPP-α. Nicotine also decreases BACE1 and PSEN1 expression, as well as ERK1 and NFκB P65 subunit expression in the cell line. Furthermore, BACE1 promoter activity is, but PSEN1 not, decreased by nicotine in the cell line. All the results suggest that activation of α4β2 nAChR decreases Aβ through regulating BACE1 transcription by ERK1-NFκB pathway. Additionally, analysis of BACE1 promoter activity by dual-luciferase reporter assay may be useful for drug screening as a high throughput method. © 2011 Springer Science+Business Media, LLC. Source


Guo L.,Shanghai JiaoTong University | Zhang J.,Shanghai JiaoTong University | Yan Q.,Shenzhen Neptunus Bioengineering Holdings Co. | Yin M.,Shanghai JiaoTong University
Human Cell | Year: 2011

RNA editing is a mechanism for generating molecular diversity by altering the genetic code at the level of RNA. The 5-HT 2C receptor is the only G protein-coupled receptor known to be edited. It has been reported that the non-edited 5-HT 2C receptor stimulates secretion of the APP metabolite APP ectodomain (APPs). However, it remains unknown whether RNA-edited 5-HT 2C receptors can also affect APPs secretion. In this study, cDNAs of five non-edited or partially/fully edited 5-HT 2C receptor isoforms (INI, VNI, VNV, VSV and VGV) were stably transfected into HEK293APPSwe cells to detect the cell proliferation and APPs secretion. The results demonstrated that the overexpression of INI and VNI caused increased proliferation of host cells while VNV, VSV and VGV caused inverse effects (P < 0.01). Compared with both control and non-edited isoform INI, APPs levels were significantly increased in the four edited 5-HT 2C receptor isoforms, VNI (P < 0.05), VNV (P < 0.05), VSV (P < 0.05) and VGV (P < 0.01). These results suggest that the RNA editing of the 5-HT 2C receptor may affect APPs secretion through different signaling pathways related to cell growth and protein processing, and that these cell models will provide appropriate useful information to study the association between the RNA editing of the serotonin 5-HT 2C receptor and APP metabolism. © 2011 Japan Human Cell Society and Springer. Source


Chen X.M.,Sun Yat Sen University | Chen X.M.,Shenzhen Neptunus Bioengineering Holdings Co. | Wei H.,Sun Yat Sen University | Yin L.,Sun Yat Sen University | Li X.S.,Sun Yat Sen University
Chinese Chemical Letters | Year: 2010

Quinazoline derivatives were synthesized from a-iminoesters via a cascade imino-Diels-Alder and then oxidation reaction catalyzed with CuBr2. This method provided a new strategy for preparing quinazoline derivatives which may be useful in the synthesis of heterocyclic intermediates. © 2010 Xing Shu Li. Source


Wu M.,Tianjin University | Xu S.,Tianjin University | Xu S.,National Engineering Research Center for Distillation Technology | Zhao J.,Shenzhen Neptunus Bioengineering Holdings Co. | And 3 more authors.
Carbohydrate Polymers | Year: 2010

A process of depolymerization of a new fucosylated chondroitin sulfate from Thelenata ananas by free radicals was developed. The fractions with different molecular weights and narrow molecular weight distribution were obtained. The parameters of the process were investigated by high-performance gel permeation chromatography. The kinetics of the depolymerization of THG by H2O2 was studied, and a possible mechanism was proposed. The results indicated that the levels of final products fragmentation and reproducibility were different depending on the conditions of depolymerization used. The fragmentation of the main chain of THG occurred randomly and obeyed pseudo-first-order kinetics, and produced species with rather narrow and unimodal distribution of molar mass. Chemical compositions of partially depolymerized samples by 1H/13C nuclear magnetic resonance spectroscopy and by elementary analyzer suggested that there was no preferential cleavage of sulfated α-l-fucopyranose side-chain, and chemical composition of products was kept almost unchanged from that of native THG. © 2010 Elsevier Ltd. All rights reserved. Source


Wu M.,Tianjin University | Xu S.,Tianjin University | Xu S.,National Engineering Research Center for Distillation Technology | Zhao J.,Shenzhen Neptunus Bioengineering Holdings Co. | And 3 more authors.
Food Chemistry | Year: 2010

A process of depolymerization of a new fucosylated chondroitin sulphate from Thelenata ananas by free-radicals was developed. The fractions with different molecular weights and a narrow molecular weight distribution was obtained. The products were characterised by physicochemical properties, FT-IR spectra and NMR spectra. The results confirm the retention of primary structure of the fractions after the depolymerization. Furthermore, the anticoagulant activity of the fractions was evaluated by the activated partial thromboplastin time (APTT). The APTT activity decreases in proportion to the molecular weight following a logarithmic-like function, and the potentiating of prolongation of APTT activity requires at least an oligosaccharide chain of about 6-8 units (6000-7000 Da). Compared to high doses of low molecular weight heparin (LMWH), a more desirable molecular weight fraction (13,950 Da) demonstrates significantly lower anticoagulant activity. Thus, the fraction has more potential as an antithrombotic agent with reduced bleeding risk relative to LMWH. © 2010 Elsevier Ltd. All rights reserved. Source

Discover hidden collaborations