3.Expression and Purification of a hbFGF Lacking Nuclear Localization Signal
Xiaoping WU ; Zhijian SU ; Qing ZHENG ; Sixian WU ; Ya FENG ; Hongyan QU ; Hua XU ; Xiaokun LI
Journal of China Pharmaceutical University 2005;(3):272-275
AIM:To study the mechanism of the unique export of one of human basic fibroblast growth factor (hbFGF) forms lacking the N-terminal nuclear localization signal (NLS),we high expressed and purified this hbFGF form in E.coli strain BL21(DE3).METHODS:The cDNA fragment of the hbFGF amplified by polymerase chain reaction (PCR) was cloned into the expression vector pET3c and expressed in BL21(DE3) by IPTG induction.The expressed hbFGF was purified by ionic exchange and heparin affinity chromatography from the supernatant of bacteria lysate.The mitogenic activity was measured by MTT.RESULTS:The expression level of hbFGF in E.coli was about 20% of the total cellular protein.The appreciable mitogenic activity of the purified hbFGF was comparable to that of hbFGF standard.CONCLUSION:The BL21(DE3)/ pET3c expression system could be used to high express hbFGF lacking NLS.The purified recombinant hbFGF was prepared and sufficient for further study.
4.A Convenient and Effective Approach for Gene Synthesis of Human Platelet Factor-4
Xiaoping WU ; Zhijian SU ; Qing ZHENG ; Sixian WU ; Hua XU ; Wen ZHAO ; Xiaokun LI
Journal of China Pharmaceutical University 2005;(6):590-593
AIM:To synthesize the human platelet factor-4(hPF4) gene with a convenient and effective approach, and high express the hPF4 gene in E. coli BL21 (DE3). METHODS: According to the primary structure of hPF4, the nucleotide sequence was synthesized using touch-down PCR method. The resultant gene fragment containing EcoR Ⅰ and Xho Ⅰ overhangs at 5' and 3' ends was cloned into the expression vector pGEX-4T-1 to construct the recombinant plasmid pGEX-4T-1-hPF4,which was then transformed into the E. coli strain BL21 (DE3). RESULTS: hPF4 gene was successfully synthesized by touchdown PCR method. A fusion protein composed of glutathione S-transferase (GST) and the recombinant hPF4 was expressed in BL21(DE3) by IPTG induction. The expression level of the fusion protein in E. coli was about 30% of the total cellular protein. CONCLUSION: Touch-down PCR may provide a convenient and effective approach to obtain other target genes. The expressed fusion protein forms the inclusion bodies, providing sufficient material for further purification and biological activities process.
5.Expression and Purification of Basic Fibroblast Growth Factor Mutant with Reduced Mitogenic Activity
Xiaoping WU ; Xiaokun LI ; Zhijian SU ; Qing ZHENG ; Sixian WU ; Hua XU ; Hongyan QU
China Biotechnology 2005;25(2):49-52
In order to decrease the potential side-effects of human basic fibroblast growth factor (hbFGF) caused by its broadspectrum mitogenic activity, a single residue of hbFGF, the residue serine 108, was replaced with neutral alanine residue to construct a mutant of hbFGF (mhbFGF) with reduced mitogenic activity. The mutant was overexpressed in Escherichia coli BL21(DE3) by IPTG induction. The expression level of mhbFGF was about 30% of the total cellular protein. The expressed mhbFGF was purified by ionic exchange and heparin affinity chromatography from the supernatant of bacteria lysate. Measured by MTT method, the effect of mhbFGF on Balb/c 3T3 cell proliferation was much lower than that of wild-type hbFGF. The purified recombinant mhbFGF was prepared and sufficient for the following pharmacological and safety studies.
6.The mitogenic activity decline of a haFGF mutant and its mechanism
Qing ZHENG ; Xiaofeng WANG ; Xiaoping WU ; Hua XU ; Qihao ZHANG ; Zhijian SU ; Xiaokun LI
Chinese Journal of Pathophysiology 1986;0(03):-
AIM: To observe the effects of the human acidic fibroblast growth factor mutant (mhaFGF), lacking 27 amino acids at N-terminal, on the proliferation and signal transduction of the hepatocarcinoma cells. METHODS: The hepatocarcinoma cells were treated with human acidic fibroblast growth factor (haFGF) and mhaFGF, respectively. The expression levels of the signal proteins, Grb2 and Erk1/2, in the hepatocarcinoma cells were detected by semi-quantitative Western-blotting after treated for 15 min. The mitogenic activity of both haFGF and mhaFGF was detected by MTT method and the cell cycle was analysed by flow cytometer (FCM) after treated for 48 h. RESULTS: The mitogenic activity and the ratio of G 1 and S phase cells in mhaFGF-treated cells were markedly lower than that of the haFGF, and close to that of the control group. The expression level of both Grb2 and Erk1/2 in the mhaFGF-treated cells were lower than those in the haFGF- treated cells. CONCLUSION: The decrease in the mitogenic activity of mhaFGF is probably associated to its down-regulating the expression of the signal molecular, MAPK-ERK1/2 and Grb2.
7.Protective effects of nmhaFGF on NRK52E cell apoptosis induced by H_2O_2
Guangfan HAI ; Hua XU ; Jing YU ; Zhijian SU ; Qing ZHENG ; Hong XU
Chinese Journal of Pathophysiology 2000;0(11):-
AIM:The present study was designed to establish H2O2-induced NRK52E cell apoptotic model and to investigate the effects and the mechanism of nmhaFGF on the NRK52E cell apoptosis induced by H2O2. METHODS: In vitro experiment, a apoptotic model of normal rat kidney epithelium (NRK52E) was made by MTT method, Hoechst33342 dyeing and flow cytosorting (FCR). NRK52E cells were cultured with different concentrations of nmhaFGF and haFGF for 24 h before H2O2 was added. The apoptotic rate was detected with FCR method. RESULTS: H2O2 at concentration of 0.4 mmol/L, the optimal condition to establish the apoptotic model, was used to treat NRK52E cells for 18h. Different doses of nmhaFGF (0.01, 0.03, 0.10, 0.30, 1.00 mg/L) reduced the apoptotic rates with the dose rising. However, the decreasing tends of apoptotic rates with dose increasing for haFGF was not so obvious. CONCLUSION: nmhaFGF protects the NRK52E cells against apoptosis. The mechanism might be connected with its non-mitogenic property.
8.Pharmacokinetics of a fusion protein for human acidic fibroblast growth factor and transcriptional activator protein in rat and its penetration across blood-brain barrier.
Penghui YANG ; Hua XU ; Qihao ZHANG ; Juan LI ; Yaoling XIONG ; Yadong HUANG ; Zhijian SU ; Qing ZHENG
Acta Pharmaceutica Sinica 2011;46(10):1204-8
This paper is to report the study of the pharmacokinetics of a fusion protein TAT-haFGF(14-154) for human acidic fibroblast growth factor and transcriptional activator protein in rat plasma, and the investigation of their penetration across blood-brain barrier in mice and rats, in order to provide a basis for clinical development and treatment of Alzheimer's disease. Enzyme-linked immunosorbent assay (ELISA) was used to determine concentration of TAT-haFGF(14-154) in rat plasma and in mouse brain homogenate; and immunohistochemistry was used to analyze the distribution in brain. The concentration-time curve fitted two-compartment open model which was linear kinetics elimination after a single intravenous injection of TAT-haFGF(14-154) in rat at the dose of 300 microg x kg(-1). The half life time was 0.049 +/- 0.03 h for distribution phase and 0.55 +/- 0.05 h for elimination phase, and the weight was 1/C2. The result showed that TAT-haFGF(14-154) could be detected in the brain by ELISA and immunohistochemistry, the elimination of TAT-haFGF(14-154) in rat was swift, and TAT-haFGF(14-154) could penetrate across the blood-brain barrier, distribute in pallium and hippocampus and locate in the nucleus.
9.Effects of survivin gene siRNA on the growth of gastric cancer cell line
Shao-Chang JIA ; Chang-Qing SU ; Wei-Bing ZHANG ; Yue-Hua WANG ; Yong-Zhong YU ;
Chinese Journal of General Surgery 2000;0(12):-
Objective To construct an expression plasmid carrying the specific siRNA of survivin gene,and to evaluate its silencing effect on the expression of survivin gene and its inhibition effect on the growth of gastric cancer cells.Methods The specific siRNA of survivin gene was designed and synthesized,and an expression plasmid pAdGFP-siRNA was constructed.Gastric cancer cell line SGC-7901 was cuhured and transferred with pAdGFP-siRNA,then the silencing of survivin gene expression and the growth inhibition of cancer cell mediated by pAdGFP-siRNA were identified.Results The growth of gastric cancer cells was inhibited after transferring the pAdGFP-siRNA,with the inhibition rate of 68.2% compared to the control group.Immunohistochemistry showed that the specific siRNA markedly silenced the expression of survivin gene in cancer cells.Conclusions The overexpression of survivin gene in gastric cancer cells results in the high proliferation and the resistance to the chemo- and radio-therapy of the cancer cells.The specific siRNA can markedly silence the expression of survivin gene and inhibit the growth of cancer cells.
10.Advances in the diagnosis of vasoinhibitory vasovagal syncope in children
Hua QING ; Xuewen SU ; Hua ZHU
International Journal of Pediatrics 2024;51(2):99-102
Vasoinhibitory vasovagal syncope(VVS-VI)in children is the most common type of responses in vasovagal syncope(VVS)and has a high incidence. VVS-VI is a recurrent disorder caused by a malfunctioning autonomic nervous system. VVS-VI can be caused by a variety of stimuli such as strong emotions,sudden changes in posture,hot and stuffy environments and prolonged standing. It was found that VVS-VI is a benign disease without organic lesions and is self-limiting and reversible,but VVS-VI children often suffer irreversible consequences due to secondary injuries. VVS-VI seriously affects the life and academic performance of children,endangers their physical and mental health,and causes anxiety among parents,so the number of studies on VVS-VI has increased in recent years. This article summarizes the progress of diagnostic research on VVS-VI in children,and provides a reference for related research.