AIM: To recombine the human alpha B-crystallin(αBcrystallin) using gene cloning technology and prokaryotic expression vector and confirm the biological activity of recombinant human αB-crystallin. METHODS: Cloning t...AIM: To recombine the human alpha B-crystallin(αBcrystallin) using gene cloning technology and prokaryotic expression vector and confirm the biological activity of recombinant human αB-crystallin. METHODS: Cloning the human αB-crystallin cDNA according to the nucleotide sequence of the human αBcrystallin, constructing the pET-28/CRYAB prokaryotic expression plasmid by restriction enzyme digestion method, and stably expressing transformed into the Escherichia coli(E. coli) DH5 alpha. The recombinant human αB-crystallin was purified by Q sepharose. By enzyme digestion analysis, Western blotting and sequencing, the recombinant human αB-crystallin was identified and the activity of its molecular protein was detected.RESULTS: Compared with the gene bank(GeneBank), the cloned human sequence of human αB-crystallin cDNA has the same open reading frame. Identification and sequencing of the cloned human αB-crystallin cDNA in prokaryotic expression vector confirmed the full length sequence, and the vector was constructed successfully. The E. coli containing plasmid pET-28/CRYAB induced by isopropyl-β-D-thiogalactoside successfully expressed the human αB-crystallin. Insulin confirmed that the recombinant human αB-crystallin has a molecular chaperone activity. CONCLUSION: The prokaryotic expression vector pET-28/CRYAB of recombinant human αB-crystallin issuccessfully constructed, and the recombinant human αBcrystallin with molecular chaperone activity is obtained, which lay a foundation for the research and application of the recombinant human αB-crystallin and its chaperone activity.展开更多
BACKGROUND： Studies of several animal models of central nervous system diseases have shown that neural progenitor cells （NPCs） can migrate to injured tissues. Stromal cell-derived factor 1 alpha （SDF-la）, and its...BACKGROUND： Studies of several animal models of central nervous system diseases have shown that neural progenitor cells （NPCs） can migrate to injured tissues. Stromal cell-derived factor 1 alpha （SDF-la）, and its primary physiological receptor CXCR4, have been shown to contribute to this process. OBJECTIVE： To investigate migration efficacy of human NPCs toward a SDF-1α gradient, and the regulatory roles of tumor necrosis factor-α （TNF-α） and interleukin-8 （IL-8） in SDF-1α/CXCR4 axis-induced migration of NPCs. DESIGN, TIME AND SETTING： An in vitro, randomized, controlled, cellular and molecular biology study was performed at the Laboratory of Department of Cell Biology, Medical College of Soochow University between October 2005 and November 2007. MATERIALS： SDF-1α and mouse anti-human CXCR4 fusion antibody were purchased from R＆D Systems, USA. TNF-αwas purchased from Biomyx Technology, USA and IL-8 was kindly provided by the Biotechnology Research Institute of Soochow University. METHODS： NPCs isolated from forebrain tissue of 9 to 10-week-old human fetuses were cultured in vitro. The cells were incubated with 0, 20, and 40 ng/mL TNF-α, or 0, 20, and 40 ng/mL IL-8, for 48 hours prior to migration assay. For antibody-blocking experiments, cells were further pretreated with 0, 20, and 40 μg/mL mouse anti-human CXCR4 fusion antibody for 2 hours. Subsequently, the transwell assay and CXCR4 blockade experiments were performed to evaluate migration of human NPCs toward a SDF-1α gradient. Serum-free culture medium without SDF-1α served as the negative control. MAIN OUTCOME MEASURES： The transwell assay was performed to evaluate migration of human NPCs toward a SDF-1α gradient, which was blocked by fusion antibody against CXCR4. In addition, CXCR4 expression in human NPCs stimulated by TNF-α and IL-8 was measured by flow cytometry. RESULTS： Results from the transwell assay demonstrated that SDF-1α was a strong chemoattractant for human NPCs （P 〈 0.01）, and 20 ng/mL produced the highest levels of migration. Anti-human CXCR4 fusion antibody significantly blocked the chemotactic effect （P 〈 0.05）. Flow cytometry results showed that treatment with TNF-α and IL-8 resulted in increased CXCR4 expression and greater chemotaxis efficiency of NPCs towards SDF-1α（P 〈 0.01）. CONCLUSION： These results demonstrated that SDF-la significantly attracted NPCs in vitro, and neutralizing anti-CXCR4 antibody could block part of this chemotactic function. TNF-α and IL-8 increased chemotaxis efficiency of NPCs towards the SDF-1αgradient by upregulating CXCR4 expression in NPCs.展开更多
AIM: The goal of this study was to characterize the AlPreceptor, its possible signal transduction pathway and itsproliferative functions in human hepatoma cell line Bel 7402.METHODS: Cell proliferation enhanced by AFl...AIM: The goal of this study was to characterize the AlPreceptor, its possible signal transduction pathway and itsproliferative functions in human hepatoma cell line Bel 7402.METHODS: Cell proliferation enhanced by AFlP was detectedby MTT assay, 3H-thymidine incorporation and S-stsgepercentage of cell cycle analysis. With radioactive labeled 125 I-AFP for receptor binding assay; cAMP acctmuation, ProteinKinase A activity were detected by radioactive immunosorbentassay and the change of intracellular free calcium ([Ca2+ ], )was monitored by scanning fluorescence intensity under TCS-NT confocal microscope. The expression of oncxgenes N- ras,p53, and p21ras in the cultured cells in vitro were detected byNorthem blotting and Western blotting respectively.RESULTS: It was demonstrated that AFP enhanced theproliferation of human hepatoma Bel 7402 cell in a dosedependlent fashion asshown in MTT assay, 3H-thymidineincorporation and S-phase percentage up to 2-fold. Twosubtypes of AFP receptors were identified in the cells withKds of 1.3 x 10-9 mol. L-1 and 9.9 x 10-8 mol. L-1 respectively.Pretreatnent of cells with AFP resulted-in a significantincrease (625 %) in cAMP accumulation. The activity ofprotein kinase A activity were increased up to 37.5, 122.6,73.7 and 61.2 % at treatment time point 2, 6, 12 and 24hours. The level of intracellular calcium were elevated afterthe treatment of alpha-fetoprotsin and achieved to 204 % at 4min. The results also showed that AFP (20 mg. L-1 ) couldupregulate the expression of N-ras oncogenes and p53 andp21ras in Bel 7402 cells. In the later case, the alteration ware 81.1%(12 h) and 97.3 %(12 h) respectively compared with control.CONCLUSION: These results demonstrate that AFP is apotential growth factor to promote the proliferation of humanhepatoma Bel 7402 cells. Its growth-regulatory effects aremediated by its specific plasma membrane receptorscoupled with its transmembrane signaling transductionthrough the pathway of cAMP-PKA and intracellular calciumto regulate the expression of oncogenes.展开更多
基金Supported by National Natural Science Foundation of China Grant (No.81270996)Science and Technology Project Foundation of Hainan Province (No.ZDYF201631)Health Science and Technology Innovation Project Foundation of Sanya (No.2016YW22)
文摘AIM: To recombine the human alpha B-crystallin(αBcrystallin) using gene cloning technology and prokaryotic expression vector and confirm the biological activity of recombinant human αB-crystallin. METHODS: Cloning the human αB-crystallin cDNA according to the nucleotide sequence of the human αBcrystallin, constructing the pET-28/CRYAB prokaryotic expression plasmid by restriction enzyme digestion method, and stably expressing transformed into the Escherichia coli(E. coli) DH5 alpha. The recombinant human αB-crystallin was purified by Q sepharose. By enzyme digestion analysis, Western blotting and sequencing, the recombinant human αB-crystallin was identified and the activity of its molecular protein was detected.RESULTS: Compared with the gene bank(GeneBank), the cloned human sequence of human αB-crystallin cDNA has the same open reading frame. Identification and sequencing of the cloned human αB-crystallin cDNA in prokaryotic expression vector confirmed the full length sequence, and the vector was constructed successfully. The E. coli containing plasmid pET-28/CRYAB induced by isopropyl-β-D-thiogalactoside successfully expressed the human αB-crystallin. Insulin confirmed that the recombinant human αB-crystallin has a molecular chaperone activity. CONCLUSION: The prokaryotic expression vector pET-28/CRYAB of recombinant human αB-crystallin issuccessfully constructed, and the recombinant human αBcrystallin with molecular chaperone activity is obtained, which lay a foundation for the research and application of the recombinant human αB-crystallin and its chaperone activity.
基金the National Natural Science Foundation of China,No.30671041the National Basic Research Program of China(973 Program),No. 2005CB623902
文摘BACKGROUND： Studies of several animal models of central nervous system diseases have shown that neural progenitor cells （NPCs） can migrate to injured tissues. Stromal cell-derived factor 1 alpha （SDF-la）, and its primary physiological receptor CXCR4, have been shown to contribute to this process. OBJECTIVE： To investigate migration efficacy of human NPCs toward a SDF-1α gradient, and the regulatory roles of tumor necrosis factor-α （TNF-α） and interleukin-8 （IL-8） in SDF-1α/CXCR4 axis-induced migration of NPCs. DESIGN, TIME AND SETTING： An in vitro, randomized, controlled, cellular and molecular biology study was performed at the Laboratory of Department of Cell Biology, Medical College of Soochow University between October 2005 and November 2007. MATERIALS： SDF-1α and mouse anti-human CXCR4 fusion antibody were purchased from R＆D Systems, USA. TNF-αwas purchased from Biomyx Technology, USA and IL-8 was kindly provided by the Biotechnology Research Institute of Soochow University. METHODS： NPCs isolated from forebrain tissue of 9 to 10-week-old human fetuses were cultured in vitro. The cells were incubated with 0, 20, and 40 ng/mL TNF-α, or 0, 20, and 40 ng/mL IL-8, for 48 hours prior to migration assay. For antibody-blocking experiments, cells were further pretreated with 0, 20, and 40 μg/mL mouse anti-human CXCR4 fusion antibody for 2 hours. Subsequently, the transwell assay and CXCR4 blockade experiments were performed to evaluate migration of human NPCs toward a SDF-1α gradient. Serum-free culture medium without SDF-1α served as the negative control. MAIN OUTCOME MEASURES： The transwell assay was performed to evaluate migration of human NPCs toward a SDF-1α gradient, which was blocked by fusion antibody against CXCR4. In addition, CXCR4 expression in human NPCs stimulated by TNF-α and IL-8 was measured by flow cytometry. RESULTS： Results from the transwell assay demonstrated that SDF-1α was a strong chemoattractant for human NPCs （P 〈 0.01）, and 20 ng/mL produced the highest levels of migration. Anti-human CXCR4 fusion antibody significantly blocked the chemotactic effect （P 〈 0.05）. Flow cytometry results showed that treatment with TNF-α and IL-8 resulted in increased CXCR4 expression and greater chemotaxis efficiency of NPCs towards SDF-1α（P 〈 0.01）. CONCLUSION： These results demonstrated that SDF-la significantly attracted NPCs in vitro, and neutralizing anti-CXCR4 antibody could block part of this chemotactic function. TNF-α and IL-8 increased chemotaxis efficiency of NPCs towards the SDF-1αgradient by upregulating CXCR4 expression in NPCs.
基金National Natural Science Foundation of China,No.39760077
文摘AIM: The goal of this study was to characterize the AlPreceptor, its possible signal transduction pathway and itsproliferative functions in human hepatoma cell line Bel 7402.METHODS: Cell proliferation enhanced by AFlP was detectedby MTT assay, 3H-thymidine incorporation and S-stsgepercentage of cell cycle analysis. With radioactive labeled 125 I-AFP for receptor binding assay; cAMP acctmuation, ProteinKinase A activity were detected by radioactive immunosorbentassay and the change of intracellular free calcium ([Ca2+ ], )was monitored by scanning fluorescence intensity under TCS-NT confocal microscope. The expression of oncxgenes N- ras,p53, and p21ras in the cultured cells in vitro were detected byNorthem blotting and Western blotting respectively.RESULTS: It was demonstrated that AFP enhanced theproliferation of human hepatoma Bel 7402 cell in a dosedependlent fashion asshown in MTT assay, 3H-thymidineincorporation and S-phase percentage up to 2-fold. Twosubtypes of AFP receptors were identified in the cells withKds of 1.3 x 10-9 mol. L-1 and 9.9 x 10-8 mol. L-1 respectively.Pretreatnent of cells with AFP resulted-in a significantincrease (625 %) in cAMP accumulation. The activity ofprotein kinase A activity were increased up to 37.5, 122.6,73.7 and 61.2 % at treatment time point 2, 6, 12 and 24hours. The level of intracellular calcium were elevated afterthe treatment of alpha-fetoprotsin and achieved to 204 % at 4min. The results also showed that AFP (20 mg. L-1 ) couldupregulate the expression of N-ras oncogenes and p53 andp21ras in Bel 7402 cells. In the later case, the alteration ware 81.1%(12 h) and 97.3 %(12 h) respectively compared with control.CONCLUSION: These results demonstrate that AFP is apotential growth factor to promote the proliferation of humanhepatoma Bel 7402 cells. Its growth-regulatory effects aremediated by its specific plasma membrane receptorscoupled with its transmembrane signaling transductionthrough the pathway of cAMP-PKA and intracellular calciumto regulate the expression of oncogenes.
