目的 合成可生物降解的基因载体，并分析其生物毒性及转染率。 方法 低分子量聚乙烯亚胺（PEI）通过双硫键交联合成可降解的高分子量PEI衍生物（SS-PEI），通过红外光谱和核磁波谱分析技术分析其化学结构，采用细胞活力实验和检测大鼠肝肾功能指标分析其细胞和体内毒性，并转染羟基荧光素修饰的siRNA（FAM-siRNA）分析细胞转染率。 结果 红外波谱和核磁波谱分析可见酰胺键的特征波谱，噻唑蓝法和肝肾功能指标显示SS-PEI不同剂量组与对照组的差异均无统计学意义（P＞0.05），SS-PEI/FAM-siRNA转染率为（76.0 ± 2.8）%。 结论 SS-PEI的合成可明显提高装载siRNA的效率，具有安全、高效等特点。
Objective To study the effect of knockdown of signal transducer and activator of transcription 3 (STAT3) expression by short hairpin RNA (shRNA) on proliferation, apoptosis and invasion of human gastric cancer cell line MKN-45 in vitro . Methods Specific shRNA plasmids to STAT3 were constructed, and then transfected into MKN-45 cells by lipofectamine methods. Cells were divided into three groups: control group, psiRNA-H1 transfected group as negative group and psiRNA-H1/STAT3 transfected group. Semi-quantitative RT-PCR and Western blotting were used to detect the expression of STAT3 mRNA and protein, respectively. Proliferation and apoptosis of the transfected cells were observed by methyl thiazolyl tetrazolium (MTT) method and flow cytometry (FCM), respectively. The invasion of the transfected MKN-45 cells was measured by Boyden chamber. Results Compared with the negative control cells, semi-quantitative RT-PCR and Western blotting showed that the expressions of STAT3 mRNA and protein were down-regulated in the psiRNA-H1/STAT3 transfected group ( P ＜ 0.05) . The subcloned recombinant plasmid expressing shRNA effectively inhibited MKN-45 cell growth and proliferation while empty plasmid had no such specific effect. Cell apoptosis rate increased significantly in psiRNA-H1/STAT3 transfected group （ P ＜ 0.01）, and the invasion of MKN-45 cells was efficiently inhabited in psiRNA-H1/STAT3 transfected group as compared with control group and psiRNA-H1 transfected group( P ＜ 0.01).Conclusion Recombinant plasmid psiRNA-H1/STAT3 shRNA significantly inhibits the proliferation and invasion of MKN-45 cells and promotes their apoptosis.
Objective To construct AWP1 (associated with protein kinase C related kinase 1) recombinant adenovirus as the tool of transferring the gene and investigate its expression and localization in human vascular endothelial cell ECV304. Methods Cloned AWP1 cDNA was inserted into the multiply clone sites (MCS) of plasmid pcDNA3 for adding flag tag, and the flag-AWP1 gene was subcloned into shuttle vector pAdTrack-CMV. After identified with restrictional enzymes, plasmid pAdTrack-flag-AWP1 was linearized by digestion with restriction endonuclease PmeⅠ, and subsequently cotransformed into E.coli BJ5183 cells with adenoviral backbone plasmid pAdEasy-1 to make homologous recombination. After linearized by PacⅠ, the homologous recombinant adenovirus plasmid transfected into 293 cells with Lipofectamine to pack recombinant adenovirus. After PCR assay of recombinant adenovirus granules, recombinant adenoviruses infected 293 cells repeatedly for obtaining the high-level adenoviruses solution. And then, the recombinant adenoviruses infected human ECV304 cells for observing the expression and localization of AWP1 under laser scanning confocal microscope (LSCM). Results PCR assay showed that recombinant adenovirus Ad-flag-AWP1 was obtained successfully; and ECV304 cells were infected high-efficiently by the homologous recombinant virus. Then, it was observed that flag-AWP1 protein expressed in ECV304 cells and distributed in the leading edges of the cell membrane. Conclusion The vectors of flag-AWP1 recombinant adenovirus are constructed, and the localization of AWP1 protein in ECV304 cells might show that AWP1 may be a potential role on the cell signal transduction.
Objective To elucidate whether glucose transporters-4 （GLUT-4） takes part in glucose uptake of mesenchymal stem cells （MSCs） and whether Akt gene improves translocation and expression of GLUT-4 in MSCs under hypoxic environment ex vivo. Methods MSCs, transfected by Akt gene and no, were cultured with normoxia (5% CO2) or hypoxia (94%N2, 1%O2 and 5% CO2) at 37 ℃ for 8 h. Glucose uptake was assayed by using radiation isotope 2-［3H］-deoxy-Dglucose (3H-G) and the expression of GLUT-4 protein and mRNA was assayed by immunocytochemistry, Western blot and RT-PCR, respectively. Results ①3 H-G intake of MSCs was significantly increased in hypoxiatransfection group than that in hypoxia-non-transfection 〔（1.39±0.13） fold, P＜0.05〕, but which was lower than that in normoxia-non-transfection group, P＜0.05. ②GLUT-4 was expressed by MSCs under any conditions. Compared with normoxia-non-transfection group, hypoxia decreased the expressions of GLUT-4 mRNA and protein significantly (P＜0.05). ③Compared with hypoxianontransfection group, the expression of GLUT-4 〔mRNA（1.756±0.152） fold, total protein in cell （1.653±0.312） fold, protein in plasma membrane （2.041±0.258） fold〕 was increased in hypoxia-transfection group significantly (P＜0.05), but which was lower than that in normoxianontransfection group (P＜0.05). ④There was significantly positive relation between 3H-G intake and GLUT-4 protein expression in plasma membrane (r=0.415, P=0.001).Conclusion GLUT-4 may take part in glucose uptake of MSCs, and the capability of Akt gene to improve MSCs anti-hypoxia may be finished by its role in increasing the expression and translocation of GLUT-4.
Objective To construct recombinant adenovirus vector co-expressing human interleukin (hIL)-10 and green fluorescent protein (GFP) for study of the expression of genes of interest in vascular smooth muscle cells （VSMCs）. Methods hIL-10 cDNA was amplified from pUCm-T/hIL-10 cDNA using polymerase chain reaction (PCR), and cloned into shuttle plasmid pShuttle-IRES-hrGFP-1. Kanamycin resistance screeninged for recombinant plasmids, which were linealized with PmeⅠand transformed into BJ5183-AD-1 containing pAdEasy-1 by electroporation after determining the insert’s sequence correct by NotⅠ and XholⅠdigestion， sequencing and basic local alignment search tool (BLAST). Prepared recombinant adenovirus plasmids were transformed into XL10-Gold cells. Amplified plasmids were transfected to AD-293 cells for packaging after being linearized with PacⅠ. PCR was used to determine target gene; The titer of the recombinant adenovirus was measured. VSMCs were transfected by recombinant adenovirus and viewed under fluorescence microscope. hIL-10 concentration in transfected VSMCs supernant was measured by enzyme linked immune sorbent assay (ELISA). Results Recombinant shuttle plasmids contained interest gene. Recombinant adenovirus had 30 kb and 3 kb fragments after digestion with PacⅠ. PCR indicated that the recombinant adenovirus contained interest gene. The titer of recombinant adenovirus was 3×10１0 efu/ml. Transfected VSMCs had GFP expression and hIL-10 concentration in supernatant was 25 ng/106 cells. Conclusion The recombinant adenovirus co-expressing hIL-10 and GFP is successfully constructed and could effectively express in VSMCs, this lays the foundation for the gene therapy of vascular intimal hyperplasia.
Objective To investigate the stable, high effective and low toxicity gene transfer vectors’ basics in research and clinical application.Methods Current status of hepatocytedirected gene transfer vectors were reviewed by history document and contemporary experimental advances analysis.Results Viral and nonviral vector systems could both transduce target genes to liver effectively with various transduction rates based on their corresponding biological characteristics.Conclusion Hepatocyte is the effective target for gene therapy of liverrelated genetic, neoplastic and infectious diseases, although the security needs to be further evaluated.
Objective To amplificate,clone and sequence the thymidine kinase (TK) gene of herpes simplex virusⅡ(HSVⅡ); to construct and appraise the fusion gene eukaryon expression vector, pcDNA3/HSVⅡ TK/angiostatin. MethodsThe Hep2 cells were infected by HSVⅡ Sav strain. HSVⅡ genomic DNA was purified from the Hep2 cells suspension and used as template to run PCR for TK gene amplification. The amplified products were cloned into PC DNA3 vector and sequenced. The vector pcDNA/HSVⅡ TK was cut by endonuclease. The gained TK gene was cloned into eukaryon expression vector. pcDNA3/angiostation, which had been constructed. ResultsCoding region of HSVⅡTK gene consisted of 1 128 bp except stop code, it encoded 376 amino acids.After cutting the new vector by endonuclease Hind Ⅲ and BamH Ⅰ,we gained the following gene fragment: 1000 bp (TK) and 700 bp (angiostation).Conclusion The fusion gene eukaryon expression vector， pcDNA3/HSVⅡ TK/angiostatin has been constructed.
Objective To construct small interfering RNA（siRNA） eukaryotic expression vector specific for human hnRNP K gene，and to observe its silencing effects on hnRNP K gene in A549 cells.Methods The expression vectors of pSUPER/hnRNP K siRNAa，pSUPER/hnRNP K siRNAc and pSUPER/siRNAn were constructed by gene recombination and then transfected into the A549 lung carcinoma cell line by using Lipofectamine2000（a and c respectively represented A and C fragments in hnRNP K coding sequence contained 19 nts，n represented nonsense fragment as control）.The mRNA and protein were harvested after 24 h and analyzed for the expression of hnRNP K by RT-PCR and Western blotting respectively.Results The siRNA vector targeted to hnRNP K successfully decreased hnRNP K mRNA and protein levels 24 h after transfection in A549 cells.Relative expressed doses of hnRNP K mRNA in lung cancer cells transfected by hnRNP K siRNAa and hnRNP K siRNAc respectively were 0.24±0.53 and 0.28±0.57 after 24 h，which were significantly lower than that in the control group（both Plt;0.01）.The gray scale values of hnRNP K protein were 0.23±0.11 and 0.28±0.09 respectively，which were also significantly lower than those in the control group（both Plt;0.05）.And pSUPER/hnRNP K siRNAa was the most effective one.Conclusion Eukaryotic expression vector of siRNA specific for hnRNP K is successfully constructed，which lays the basis for the function study of hnRNP K gene and its application in the treatment of lung carcinoma.
Objective To determine if mesenchymal stem cells ( MSCs) could be reconstructed as a vehicle for angiopoietin-1 ( Ang1) gene therapy in lung injury. Methods MSCs were obtained from adult male inbred mice and cultured to passage four. The cells were identified by fluorescence-activated cell sorting ( FACS) analysis and cell differentiation detection. Lentiviral vectors contained GFP and Ang1 gene were conducted in 293T cells through three plasmids co-transfection method. Then MSCs were transduced with Ang1 gene efficiently through lentiviral vectors. The mRNA expression of Ang1 in MSCs was detected by RT-PCR before and after transfection. Also fluorescence from MSCs was detected by fluorescence microscope every day after transfection. Two hours after LPS inhalation, mice were infused via jugular veinwith normal saline ( NS group) , lentiviral vector carrying Ang1 ( Ang1 group) , lentiviral vector carrying GFP ( MSCs group) , and lentiviral vector carrying Ang1 /GFP ( MSCs-Ang1 group) , respectively. Kaplan-Meier survival analysis was performed to compare the effects of MSCs-Ang1 on survival. And ectogenic MSCs origined lung cells were investigated in receipt mice. Results After passaged and purification,MSCs were confirmed to have the potential of differentiation. The lentiviral vectors carrying Ang1 and GFP were also identified. After transfection, the mRNA expression of Ang1 in MSCs was enhanced. Through the fluorescence microscope,MSCs get the most green fluorescence expression five days after the transfection when MOI was 20. Kaplan-Meier survival analysis showed that MSCs-Ang1 infusion had improved survival rates of lung injury rats compared with the control, but it did not reach statistical significance ( P = 0. 066) . Cells expressing GFP in lung tissues can be observed after MSCs were transplanted in vivo. Conclusions MSCs expressing Ang1 high can be constructed through lentiviral vector transfer, and MSCs-origined cells can be detected in receipt lungs after transplantation. So MSCs may serve as a vehicle for gene therapy in lung injury.
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.