Objective To construct the mouse NF-κB P65 subunit expression plasmid, and identify its biological activity. Methods NF-κB P65 siRNA retrovirus expression vectors were reconstructed by molecular clone technology. Recombinant vectors were transfected into 293E package cells and virus suspension was collected. RT-PCR was used to detect the expression level of NF-κB P65 mRNA and TNF-α mRNA at different time-point of LPS stimulation. Western blot was performed to analyze the protein level of NF-κB P65. ELISA was applied to detect the expression level of TNF-α released by LPS-stimulated J774A.1. Results NF-κB P65 siRNA retrovirus expression vectors of mouse were successfully constructed. From2 hours after the stimulation of LPS, the expression level of NF-κB P65 mRNA of the siRNA group was obviously lower than the scramble control group ( 0.91 ±0.03 vs. 1.02 ±0.02, Plt;0.01) . At24,36, 48 and 72 hours after the LPS stimulation, the expression level of NF-κB P65 protein of the siRNA group was significantly decreased compared with the scramble control group ( 0.97 ±0.02 vs. 1.01 ±0.01, 0.94 ± 0.01 vs. 1.02 ±0. 01,0.94 ±0.02 vs. 1.02 ±0.01, 0.93 ±0.01 vs. 1.00 ±0.02, Plt;0. 05) . At 2, 6, 12, 24 hours after the LPS stimulation, both the expression level of TNF-α mRNA and the content of TNF-α in the culture medium supernatant of the siRNA group were lower than the scramble control group ( Plt;0. 01) . Conclusions The construction of NF-κB P65 siRNA retrovirus expression vectors is feasible. Inflammation factors in mouse monocyte-macrophages are significantly inhibited after NF-κB expression is depressed by RNA interference technology, which may be applied to prevent and treat excessive inflammatory reaction in acute lung injury.
To construct the retroviral vector containing human interleukin 1 receptor antagonist (IL-1Ra)and to investigate the property of the transfected articular chondrocytes from osteoarthritic patients in vitro. Methods Retroviral vector PLXRN carrying IL-1Ra (PLXRN-IL-1Ra) gene was constructed by inserting IL-1Ra gene at the sites of Sal I and BamH I. The recombinant retroviral plasmid was homologously recombinated in bacterial cells. After screening and ampl ification, the recombinant retroviral plasmid was obtained and transfected into PT67 cells. The repl ication-defective retrovirus PLXRN-IL- 1Ra was packed and ampl ified in the PT67 cells. Viral titer was determined by infecting NIH/3T3 cells with serially diluted viral supernatants produced with a control vector. Experiments were divided into 3 groups: non-transducted group (group A), PLXRN transduction group (group B), PLXRN-IL-1Ra transduction group (group C). Primary articular chondrocytes from osteoarthritic patients were transduced with PLXRN and PLXRN-IL-1Ra.The positive chondrocytes clones, which were G418- resistant, were cultured for 3-4 weeks after being selected by G418. The expression of IL-1Ra mRNA in the chondrocytes was determined by RT-PCR. Levels of IL-1Ra protein synthesis in the supernatants were measured by ELISA. Results Restric tive endonuclease identification and gene sequencing confirmed that the recombinant contained IL-1Ra cDNA．Virus titer could reach 3 × 104 CFU/mL. Primary chondrocytes cultured in vitro were polygonal or spindle and were stained with purple particles by toluidine blue staining. After stable transduction into the chondrocytes the 311 bp fragment of IL-1Ra was detected in group C by semi-quantitative RT-PCR. ELISA showed that IL-1Ra in supernatants of the group A and group B were below the level of detection. The concentrations were（60.47 ± 15.13）ng/L in group C .There were significant differences between gene transduction group and control groups (P lt; 0.05). Conclusion The construction of recombinant retrovirus vector by homologous recombination in bacterial cells can be quickly and easily performed. Stable and effective expression of IL-1Ra can be achieved by transduction with retroviral vectors in osteoarthritic articular chondrocytes, indicating potential util ity in gene therapy for osteoarthritis．
The human wild-type Rb cDNA has been inserted into a retrovirus vector DOL and introduced into the human breast cancer cell MDAMB468,which has a large deletion of exons 3-27 of Rb genes,by electroporation transfection techniques.The exogenous Rb gene expresses the 110kd Rb protein.The morphology of the transfected cells is similar to that of the parent MDAMB468 cells.With the expression of Rb protein,the growth rate of MDAMB468 cells decreases by about 50%,and the colony formation ability in soft agaris repressed completely.After injection of 3times;106Rb+ cells and Rb-MDAMB468 cells into nude mice,the tumors formed from 106Rb+ cells are smaller than those from Rb-cells.The cell population of G1 and S phase of Rb+ MDAMB468 cells increases and the proliferation quotient decreases by about 50%.This result supports the former report the Rb protein. （Chin J Ocul Fundus Dis,1993,9:135-140）