Objective To investigate the heterotopic odontogenesis ability ofDelta1 gene transfected human dental pulp stem cell (DPSC) and nanohydroxyapatite/collagen (nHAC) composite scaffold. Methods The cultured human DPSC was transfected with Delta1-enhanced green fluorescent protein recombinant retrovirus supernatant，and was selected by puromycin to obtain the positive cell clone. The experimental group contained the Delta1 transfected DPSC; however, the control group did not contain the Delta1 transfected DPSC but contained DPSC transfected with vectors only. The cells were seeded into the nHAC carriers and were cultured in the odonto-inductive medium. The growth of the transduced cells in the carriers was observed by the fluorescent phase contrast microscope and the scanning electron microscope (SEM). The cell-carrier composites were subcutaneously transplanted into the Delta1 transfected 8 nude mice (female, 8 weeks old). Eight weeks after operation,the composites were taken out and tested with the histological and the immunohistological methods.Results Green fluorescence was observed inthe cells in the experimental group, which were grown in the carriers by the fluorescent phase contrast microscope. Observed by SEM, great amounts of transduced DPSC were observed along the scaffold materials, even filling the porous structures of nHAC and secreting a lot of extracellular matrix. However, in the control group, much fewer cells were found in the carriers. All the 4 Delta1 transduced DPSC-nHAC composites produced dentin-like structures that lined the surfaces of some nHAC porous structures. The odontoblast-like cells extended the cytoplasmic processes into the dentinal matrix, which was interfaced with a pulp-like interstitial tissue infiltrated with the blood vessels. Dentin sialophosphoprotein was expressed in the odontoblast-like cells when immunohisochemistry was performed. The morphology of the control composite was a typical one of the fibrous connective tissue,and only a little dentin-like structure was found in 2 of the 8 control transplants. Conclution DPSC can be used as the recipient cell of the Delta1 gene for expression and secretion of the Delta1 protein. The composites of the transfected cells and nHAC can induce heterotopic odontogenesis, which indicates that Delta1 is a novel candidate for the gene enhanced dentinpulp composite engineering.
【Abstract】ObjectiveTo construct eukaryotic expression vector pSecTag2/HygroB-CD59 of human CD59 and transfect NIH3T3 cells after encapsulated by chitosan. MethodsThe human CD59 fragments were obtained by PCR form CD59-pGEM-T Easy Vector, cloned into the eukaryotic expression vector pSecTag2/HygroB, identified by restriction endonuclease’s digestion and DNA sequencing. After the particles of pSecTag2/HygroB-CD59 were encapsulated by chitosan, the NIH3T3 cells were transfected by chitosanCD59 nanoparticles and detected CD59 expression by immunohistochemistry stain. ResultsThe CD59 fragment was 312 bp. Its sequence was as same as CD59 cDNA in Genbank. After having been transfected by chitosan-CD59 nanoparticles in 24 hours, the 3T3 cells showed diffusely positive in the cytoplasms by anti-CD59 immunohistochemistry. ConclusionThe eukaryotic expression vector of human CD59 is constructed and transfected to NIH3T3 cells after encapsulated by chitosan. It will be very helpful for further study on transgenic livers.
【Abstract】 Objective To investigate the secretion of target gene and differentiation of BMSCs transfected by TGF-β1 and IGF-1 gene alone and together into chondrocytes and to provide a new method for culturing seed cells in cartilage tissue engineering. Methods The plasmids pcDNA3.1-IGF-1 and pcDNA3.1-TGF-β1 were ampl ified and extracted, then cut by enzymes, electrophoresed and analyzed its sequence. BMSCs of Wistar rats were separated and purificated by the density gradient centrifugation and adherent separation. The morphologic changes of primary and passaged cells were observed by inverted phase contrast microscope and cell surface markers were detected by immunofluorescence method. According to the transfect situation, the BMSCs were divided into 5 groups, the non-transfected group (Group A), the group transfected by empty vector (Group B), the group transfected by TGF-β1 (Group C), the group transfected by IGF-1 (Group D) and the group transfected both by TGF-β1 and IGF-1 (Group E). After being transfected, the cells were selected, then the prol iferation activity was tested by MTT and expression levels were tested by RT-PCR and Western blot. Results The result of electrophoresis showedthat sequence of two bands of the target genes, IGF-1 and TGF-β1, was identical with the sequence of GeneBank cDNA. A few adherent cells appeared after 24 hours culture, typical cluster formed on the forth or fifth days, and 80%-90% of the cells fused with each other on the ninth or tenth days. The morphology of the cells became similar after passaging. The immunofluorescence method showed that BMSCs were positive for CD29 and CD44, but negative for CD34 and CD45. A few cells died after 24 hoursof transfection, cell clone formed at 3 weeks after selection, and the cells could be passaged at the forth week, most cells became polygonal. The boundary of some cells was obscure. The cells were round and their nucleus were asymmetry with the particles which were around the nucleus obviously. The absorbency values of the cells tested by MTT at the wavelength of 490 nm were0.432 ± 0.038 in group A, 0.428 ± 0.041 in group B, 0.664 ± 0.086 in group C, 0.655 ± 0.045 in group D and 0.833 ± 0.103 in group E. The differences between groups A, B and groups C, D, E were significant (P lt; 0.01). The differences between groups A and B or between C, D and E were not significant (P gt; 0.05)。RT-PCR and Western blot was served to detect the expression of the target gene and protein. TGF-β1 was the highest in group C, 0.925 0 ± 0.022 0, 124.341 7 ± 2.982 0, followed by group E, 0.771 7 ± 0.012 0, 101.766 7 ± 1.241 0（P lt; 0.01）; The expression of IGF-1 was the highest in group E, 1.020 0 ± 0.026 0, 128.171 7 ± 9.152 0, followed by group D, 0.465 0 ± 0.042 0, 111.045 0 ± 6.248 0 （P lt; 0.01）. And the expression of collagen II was the hignest in group E, 0.980 0 ± 0.034 0, 120.355 0 ± 12.550 0, followed by group C, 0.720 0 ± 0.026 0, 72.246 7 ± 7.364 0（P lt; 0.01）. Conclusion The repairment of cartilage defects by BMSCs transfected with TGF-β1 and IGF-1 gene together hasa good prospect and important significance of cl inic appl ication in cartilage tissue engineering.
Objective To establish a eukaryotic cell line that can express soluble human leucocyte antigen G1(sHLA-G1) stably. Methods The recombinant plasmid pcDNA3-sHLA-G1 is transfected by a novel nonviral, electroporation-based gene transfer method termed nucleofection into the host cell lymphoblastoid cell line (LCL)721.221 which does not express any HLA-classical I molecules. After selection by G418, the cell line stably expressingsHLA-G1 is identified by RTPCR and Dot-ELISA with HLA-G1 specific monoclonal antibody MEM-G/9. Results The efficiency of transfection for LCL721.221 is about 14% by nucleofection. The specific band forsHLA-G1 was found by RT-PCR assay from the transfections and the protein ofsHLA-G1 in the supernatant of the transfections was detected by Dot-ELISA assay. Both confirmed that the eukaryotic cell line expressingsHLA-G1 has been established successfully at genic and proteinic levels. Conclusion In this study, the eukaryotic cell line expressingsHLA-G1 have been established successfully by nucleofection.
Objective To study the adenovirus-mediated human bone morphogenetic protein-2 gene （Ad-hBMP-2）transferred to the intervertebral disc cells of the New Zealand rabbit in vitro. Methods The cells of New Zealand white rabbitswere isolated from their lumbar discs. The cells were grown in the monolayer and treated with an adenovirus encoding the LacZ gene (Ad-LacZ) and Ad-hBMP-2 (50,100, 150 MOI,multiplicity of infection) in the Dulbecco’s Modified Eagle Medium and the Ham’s F-12 Medium in vitro. Three days after the Ad-hBMP-2 treatment,the expression of hBMP-2 in the cells that had been infected by different dosesof MOI was determined by immunofluorescence and the Western blot analysis, and the expression was determined in the cells with the Ad-LacZ treatment in a dose of 150 MOI. Six days after the Ad-hBMP-2 treatment, mRNA was extracted for the reverse transcription polymerase chain reaction (RT-PCR) and the difference was detected between the control group and the culture group that was treated withAd-hBMP-2 in doses of 50, 100 and 150 MOI so that the expressions of aggrecan and collagen ⅡmRNA could be observed. Results The expression of hBMP-2 in the cells was gradually increased after the transfection in an increasing dose, which was observed by immunofluorescence and the Western blot analysis. At 6 days the aggrecan and collagen type Ⅱ mRNA expressions were up-regulated by Ad-hBMP-2 after the transfection at an increasing viral concentration in the dosedependent manner. Conclusion The results show that Ad-hBMP-2 can transfect the rabbit intervertebral disc cells in vitro with a high efficiency rate and the expression of hBMP-2 after theinfection is dose-dependent in the manner. AdhBMP-2 after transfection can up-regulate the expression of aggrecan and collagen Ⅱ mRNA at an increasing viral concentration.
目的:探讨丙型肝炎病毒非结构蛋白NS4B在原发性肝癌发生中的作用,及其发生机制。方法:设置对照组、空白载体PCXN2组、转染NS4B组。使用脂质体介导法,转染丙型肝炎病毒非结构蛋白重组质粒NS4B进入Chang肝细胞内,并用G418筛选。绘制生长曲线,分别用流式细胞仪检测瞬时表达及稳定表达时肝细胞凋亡率,用均数±标准差表示,统计学分析采用Dunnett t检验及q检验。结果:瞬时表达各组(PCXN2,NS4B)凋亡率分别为:(918±060)%,(445±053)%。稳定表达各组(PCXN2,NS4B)凋亡率分别为:(1575±209)%,(366±034)%。与PCXN2组比较Plt;001。结论:NS4B抑制肝细胞凋亡率,可能导致肝细胞异常增殖,诱导肝癌发生。
Objective To construct a green fluorescent protein expression plasmid pEGFP-C3-anti-TAG72 scFv-CD28, containing anti-TAG72 single chain variable fragment (scFv) fused into the transmembrane and intracellular domain of the signal-transducing chain of CD28 gene, and to transfect it into peripheral blood mononuclear cells． Methods Recombinant transmembrane and intracellular domain of CD28 cDNA and anti-TAG72 scFv cDNA fragment was subcloned into pEGFP-C3 vector. Recombinant clones were selected by Kanamyein， and then identified by PCR， enzyme digestion analysis and DNA sequencing. The recombinant plasmid was transfected into peripheral blood mononuclear cells by means of lipofection. The recombinant protein expression was confirmed by immunocytochemistry, laser scanning confocal microscope, PCR and Western blot analysis. Results The fused gene fragment of anti-TAG72 scFv-CD28 was successfully inserted into pEGFP-C3 plasmid, and it was confirmed by enzyme digestion and DNA sequencing. The fused anti-TAG72 scFv-CD28 gene and its protein was identified in peripheral blood mononuclear cells． Conclusion The eukaryotic expression plasmid pEGFP-C3-anti-TAG72 scFv-CD28 was successfully constructed and transiently expressed in peripheral blood mononuclear cells， which would lay a foundation for further studies on the role of it to activate tumor-associated antigen-specific T lymphocyte, for generating of modified T lymphocytes targeting gastrointestinal tumors.
ObjectiveTo elucidate whether hypoxia induced factor-1α (HIF-1α) gene improved hypoxia tolerant capability of bone marrow mesenchymal stem cells uptake(MSCs) or not and whether the capability was related to glucose uptake increase in hypoxia MSCs ex vivo or not. MethodsMSCs were randomly divided into normoxia non-HIF-1α transfection group (control group), normoxia HIF-1α transfection group, hypoxia non-HIF-1α transfection group, and hypoxia HIF-1α transfection group and then each group was cultured with normoxia (5% CO2 at 37 ℃) or hypoxia (94% N2, 1% O2, 5% CO2 at 37 ℃) for 8 h, respectively. Finally, the expressions of HIF-1α were detected by immunocytochemistry, RT-PCR, and Western blot methods, respectively. Apoptosis ratio (AR) and death ratio (DR) were tested by flow cytometry. The proliferation was detected by MTT method. Glucose uptake was assayed by radiation isotope method. Results① Compared with the normoxia non-HIF-1α transfection group, the expression of HIF-1α mRNA significantly increased (Plt;0.01) in the normoxia HIF-1α transfection group except for its protein (P=0.187); Both of mRNA and protein expressions of HIF-1α in the hypoxia HIF-1α transfection group were significantly higher than those in the hypoxia non-HIF-1α transfection group (Plt;0.01). ② The AR (P=0.001) and DR (P=0.003) in the hypoxia HIF-1α transfection group were significantly lower thanthose in the hypoxia non-HIF-1α transfection group, both of which were significantly higher than those in the normoxia non-HIF-1α transfection group (Plt;0.01). ③ The proliferation of MSCs in the hypoxia HIF-1α transfection group was significantly higher than that in the hypoxia non-HIF-1α transfection group (P=0.004), which significantly lower than that in the normoxia non-HIF-1α transfection group (P=0.001). ④ Compared with the hypoxia non-HIF-1α transfection group, the 3H-G uptake capability (P=0.004) of MSCs significantly increased in the hypoxia HIF-1α transfection group, which was significantly lower than that in the normoxia non-HIF-1α transfection group (P=0.001). ⑤ There were significantly negative relation between AR and HIF-1α protein (r=－0.71，P=0.005) or 3H-G uptake (r=－0.65，P=0.004), and significantly positive relation between HIF-1α protein expression and 3H-G uptake (r=0.77, P=0.003). ConclusionHIF-1α gene significantly improves anti-hypoxia capability of MSCs, which is fulfilled by increasing glucose upake.
Objective To compare the effect of mosaicplasty, mosaicplasty with gene enhanced tissue engineering and mosaicplasty with the gels of non-gene transduced BMSCs in alginate on the treatment of acute osteochondral defects. Methods Western blot test was conducted to detect the expression of hTGF-β1, Col II and Aggrecan in 3 groups, namely hTGF-β1 transduction group, Adv-βgal transduction group and blank control group without transduction. Eighteen 6-month-old Shanghai mascul ine goats weighing 22-25 kg were randomized into groups A, B and C (n=6). BMSCs were isolatedfrom the autologous bone marrow of groups B and C, and were subcultured to get the cells at passage 3. In group B, the BMSCs were transduced with hTGF-β1. For the animals of 3 groups, acute cyl indrical defects 5 mm in diameter and 3 mm in depth were created in the weight bearing area of the medial femoral condyle of hind l imbs. In group A, the autologous osteochondral mosaicplasty was performed to repair the defect; in group B, besides the mosaicplasty, the dead space between the cyl indrical grafts and the host cartilage were injected with the suspension of hTGF-β1 gene transduced autogenous BMSCs in sodium alginate, and CaCl2 was dropped into it to form calcium alginate gels; in group C, the method was the same as the group B, but the BMSCs were not transduced. General condition of the goats after operation was observed, the goats were killed 12 and 24 weeks after operation to receive gross and histology observation, which was evaluated by the histological grading scale of O’Driscoll, Keeley and Salter. Immunohistochemistry and TEM observation were performed 24 weeks after operation. Results Western blot test showed the expression of the hTGF-β1, Col II and the Aggrecan in the hTGF-β1 transduction group were significantly higher than that of the Adv-βgal transduction and the blank control groups. All the goats survived until the end of experiment and all the wounds healed by first intention. Gross observation revealed the boundaries of the reparative tissue in group B were indistinct, with smooth and continuous surfaces of the whole repaired area; while there were gaps in the cartilage spaces of groups A and C. Histology observation showed the dead space between the cyl indrical grafts in group A had fibrocartilage-l ike repair tissue, fill ing of fibrous tissue or overgrowth of the adjacent cartilage; the chondrocytes in group B had regular arrangements, with favorable integrations; while the dead space between the cyl indrical grafts in group C had fibrocartilage-l ike repair tissue, with the existence of gaps. The histology scores of group B at different time points were significantly higher than that of groups A and C, and group C was better than group A (P lt; 0.05); for group B, significant difference was detected between 12 weeks and 24 weeks in the histology score (P lt; 0.05）. Immunohistochemistry staining for Col II 24 weeks after operation showed the chondrocytes and lacuna of the reparative tissue in group B was obviously stained, while groups A and C presented l ight staining. TEM observation showed there were typical chondrocytes in the reparative tissue in group B, while parallel or interlaced arrangement collagen fiber existed in groups A and C. Conclusion Combining mosaicplasty with tissue engineering methods can solve theproblem caused by single use of mosaicplasty, including the poor concrescence of the remnant defect and poor integration with host cartilages.