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Objective: To isolate, culture and identify rabbit bone mesenchymal stem cells (BMSCs) so as to explore the optimal conditions for lentiviral vector-mediated enhanced green fluorescent protein (eGFP) infection in rabbit BMSCs and screen stable transfected BMSCs in rabbits. Methods: BMSCs were obtained by whole bone marrow adherence method. The osteogenic, chondrogenic and adipogenic differentiation of BMSCs was made by alizarin red, toluidine blue and oil red O staining, respectively. The expressions of CD44 and CD90 were detected by immunofluorescence. The concentration of puromycin was used to screen the minimum lethal concentration of BMSCs; the lentiviral vector with multiplicity of infection (MOI) of 50, 100, 150 and 200 mediated eGFP BMSCs were infected; the fluorescence expression was observed under an inverted microscope, and the stable transformation system was screened with puromycin. Results: When MOI was 150, lentiviral vector-mediated eGFP infection of rabbit BMSCs was the most efficient. The optimum concentration of puromycin for stable transfection of rabbit BMSCs was 1.0 μg/mL. Conclusion: Rabbit BMSCs were successfully cultured in this experiment. The stem cells were labeled with lentivirus-mediated GFP and stable transfected rabbit BMSCs were screened. A simple and effective stem cell labeling method was established to label BMSCs in vivo.
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Objective: To develop retrovirus-mediated transfer of the fusion gene encoding EGFP-BMP2 in mesenchymal stem cells. Methods: Mesenchymal stem cells from New Zealand white rabbits were transduced with retroviral pLEGFP-BMP2 vector by the optimized retroviral transduction protocol. Fluorescent microscopy's examination was to evaluate the results of the transduction, flow cytometers analysis was to evaluate the transduction efficiency and the Fluorescence-activated cell sorting method was to sort the transduced cells. Bioactivity test from C2C12K4 cells was to show the expression and bio-activity of the fusion gene. Results: Fluorescent microscopy showed the success of the transduction. By flow cytometer's analysis, the mean efficiency of the transduction with EGFP was (42. 8 ± 6. 1)% SD. Transduced cells were sorted efficiently by the fluorescence-activated cell sorting method and after sorting, almost of those showed the expression of BMP2. Fluorescently and strongly bioactivity test for C2C12 K4 cells demonstrated that fluorescent materials were located the surface of cells and the activity of luciferase increased compared with the control. Analysis of long-term expression showed there was no difference between 2 week-time point and 3 month-time point of culture post-sorting. Conclusion: Mesenchymal stem cells can be transduced efficiently by retrovirus-mediated transfer of the fusion gene encoding EGFP-BMP2, the highly pure transduced cells are obtained by the fluorescence-activated cell sorting technique, the expressed chimeric protein embraced the double bioactivity of EGFP and BMP2, and moreover, the expression had not attenuated over time.
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Objective To develop retrovirus-mediated transfer of the fusion gene encoding EGFP-BMP2 in mesenchymal stem cells. Methods Mesenchymal stem cells from New Zealand white rabbits were transduced with retroviral pLEGFP-BMP2 vector by the optimized retroviral transduction protocol. Fluorescent microscopy's examination was to evaluate the results of the transduction, flow cytometer's analysis was to evaluate the transduction efficiency and the Fluorescence-activated cell sorting method was to sort the transduced cells. Bioactivity test from C2C12K4 cells was to show the expression and bio-activity of the fusion gene. Results Fluorescent microscopy showed the success of the transduction. By flow cytometer's analysis, the mean efficiency of the transduction with EGFP was (42.8±6.1)% SD. Transduced cells were sorted efficiently by the fluorescence-activated cell sorting method and after sorting, almost of those showed the expression of BMP2. Fluorescently and strongly bioactivity test for C2C12K4 cells demonstrated that fluorescent materials were located the surface of cells and the activity of luciferase increased compared with the control. Analysis of long-term expression showed there was no difference between 2 week-time point and 3 month-time point of culture post-sorting. Conclusion Mesenchymal stem cells can be transduced efficiently by retrovirus-mediated transfer of the fusion gene encoding EGFP-BMP2, the highly pure transduced cells are obtained by the fluorescence-activated cell sorting technique, the expressed chimeric protein embraced the double bioactivity of EGFP and BMP2, and moreover, the expression had not attenuated over time.
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Objective To evaluate the effects of adeno-associated virus-enhanced green fluorescent protein (AAV-EGFP)on the biologic behavior of rabbit's bone marrow stromal cells(BMSCs)by means of a simple method of culturing and osteogenic induction in vitro so as to find an ideal viral vector and cell tracing mark for tissue en- gineering.Methods Total bone marrow culture was conducted to obtain rabbit BMSCs which were then induced in the osteogenic direction.The morphology of the cells was observed continuously,and their surface antigen and ossification were detected by alkali phosphatase stain and Von Kossa stain.On the basis of the above results, AAV-EGFP was transfected into the induced cells.The morphologic changes of the cells,the expression time and intensity of fluorescent light were observed.The transfection efficiency was detected to find the best multiplicity of infection(MOI)value.The cell growth curves were drawn to evaluate the biologic effects of AAV-EGFP on the cyto-activity.Results The morphology and purity of the rabbit BMSCs obtained were good.The ossification of the cells was significant after osteogenic induction.The best MOI value was found to be 1?10~5.The expression intensity of fluorescent light was strong with the expression time more than eight weeks so that the fluorescent light could be observed after cell generations.The transfection efficiency of AAV was high without significant biologic effects on the cyto-activity.Conclusions The total bone marrow culture and in vitro cell induction can satisfy the requirements for seeding cells in tissue engineering.AAV is an ideal viral vector for tissue engineering.Transfection of AAV-EGFP to cells could be an ideal method for cell tracing mark.
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Objective Making the fusion protein of IgG-binding peptide with enhanced green fluorescent protein(EGFP) and determining its bioactivity.Methods The enhanced green fluorescent protein(EGFP) gene was cloned into pEZZ 18 vector containing ZZ peptide gene to construct expression vector pSpA-EGFP-His.The fusion protein was expressed in E.coliDH5? and its bioactivity was detected by competitive ELISA and fluorescence properties.Results The fusion protein migrated at approximately 42kD in SDS-PAGE,which correspond to the theoretical molecular weight.The spectra of SpA-EGFP fusion protein was similar to what was reported.SpA-EGFP competed with SpA-Peroxidase to bind IgG.Conclusion The plasmid pSpA-EGFP-His correctly expressed in E.coli.The fusion protein retains the bifunctional effects of EGFP and IgG-binding activity.
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Objective To construct and identify the screening vector pUC18-EGFP,using EGFP as an indicator. Methods The EGFP gene was prepared by PCR and cloned into pUC18 resulting the vector pUC18-EGFP. Then DNA fragment was inserted into the MCS of pUC18-EGFP to test its practicability based on green fluorescence. Results The pUC18-EGFP was confirmed correctly by restriction enzyme analyses. The pUC18-EGFP was used to select recombinants. The green strains on the plate were confirmed by restriction enzyme and DNA analyses,which were E.coli harboring recombinants. Conclusion The screening vector PUCl8-EGFP was constructed successfully. Thus,we can select the positive clones on plates based on the green fluorescence of EGFP.