OBJECTIVE: To analysis the biological characteristics of human fibroblasts transfected by human telomerase reverse transcriptase (hTERT) eucaryotic expression plasmid pGRN145. METHODS: Fibroblasts from children’s foreskin were isolated and cultured in vitro, and the fibroblasts were transfected by pGRN145 with Lipofec-tAMINE PLUS Reagent. After strict screening of hygromycin B, the positive clones were subcultured. The telomerase activity was detected by RT-PCR and TRAP-PCR technique. The cell generation cycle and apoptosis rate were detected by flow cytometry to investigate the proliferative characteristics after transfection, and the chromosome karyotype of transformed cells was analyzed. The collagen secreted by transformed cells was detected by immunohistochemical staining. RESULTS: The morphological properties of fibroblasts did not change obviously after transfection. There were telomerase activity in transfected fibroblasts, while it could not be detected in pre-transfection fibroblasts. The cell generation cycle had no obvious changes between pre-transfection and post-transfection. However, the apoptosis rate of transfected fibroblasts were decreased compared with that of pre-transfection. The fibroblasts transfected by pGRN145 maintained the normal diploid karyotype, as well as the cells could normally secret type I and III collagen. CONCLUSION: The human fibroblasts transfected by pGRN145 has telomerase activity with prolonged life span of culture, which preliminarily proves the availability of establishing standard seeding cell lines of tissue engineering by hTERT plasmid transfection techniques.
Objective To observe the inhibitory effects of local co-transfection of tissuetype plasminogen activator(tPA) gene and proliferating cell nuclear antigen antisense oligodeoxynucleotides(PCNA-ASODN) on the intima proliferation and restenosis of autograft artery in rabbits. Methods One hundred and twenty male Zelanian rabbits were randomly divided into four groups(n=30, in each group): control group, PCNA-ASODN group, tPA group and tPA+PCNAASODN group. The left and right external iliac arteries (length 1.0 cm) were transplanted reciprocally. The transplanted arteries were respectively soaked in lipofection, PCNAASODN, pBudCE4.1/tPA and pBudCE4.1/tPA+PCNA-ASODN solution about 15 minutes. The transplanted arteries were sutured with 9-0 sutures soaked in PCNA-ASODN and pBudCE4.1/tPA solution. Each group were divided into five subgroups(n=6, in each subgroup) according to the sacrifice time (3 d, 7 d, 14 d, 28 d and 56 d after operation). On every sacrifice time point, the vascular specimens were harvested. The thrombocyte assembling and thrombus forming lining vessel wall were observed by scanning electron microscope. The pathological morphology of transplanted arteries were observed under microscope(HE). The intimal areas and stenosis ratio(%) of transplanted arteries were calculate and analyzed statistically among groups by computer system. The mRNA expression of tPA gene in transplanted ressel wall was detected with vevere transcriptionPCR(RT-PCR). The number of PCNA positive cells in transplanted vessel wall was counted by SP immunochemisty.Results The mRNA expression of tPA gene in the transplanted vessel wall in tPA and tPA+PCNA-ASODN groups was higher than that of the other two groups(P＜0.01).The number of PCNA positive cells in the transplanted arteries in PCNAASODN, tPA and tPA+PCNAASODN groups were significantly lower than that of control group(P＜0.05，P＜0.01). The intimal areas and degrees of luminal stenosis of PCNAASODN, tPA and tPA+PCNAASODN groups were lower than those of control group(P＜0.05，P＜0.01), and those of tPA＋ PCNA-ASODN group were lower than those of PCNA-ASODN and tPA groups(P＜0.05). Scanning electron microscopy showed that there were a few thrombocytes lining the vessel wall of tPA group and tPA+PCNAASODN group and no thrombus, whereas there were abundant thrombocytes and thrombi lining the vessel wall of the control group. Conclusion Co-transfection of tPA gene and PCNA-ASODN can effectively inhibit the proliferation of VSMC, hyperplasia of intima and restenosis of transplanted artery.
Objective To investigate the effects of recombinant adenovirus-mediated co-transfection of carcinoembryonic antigen (CEA) gene and erythropoietin (EPO) gene on promoting hematopoietic stem cells directly producing erythrocyte vaccine against colon cancer. Methods The expression adenovirus vectors carrying CEA and EPO or green fluorescent protein (GFP) gene were constructed respectively, and recombinant adenovirus carrying CEA, EPO or GFP were packaged and produced respectively. The bone marrow-derived mesenchymal stem cells (MSCs) of mice were isolated and cultured in vitro by anti-CD117 magnetic bead separation, and were transfected with CEA (CEA group), EPO (EPO group) or GFP (blank vector group), co-transfected with CEA and EPO (CEA-EPO group). The expressionsof CEA and EPO gene and its protein after transfection in supernatant fluid of culture were detected by realtime-PCR and Western blot method in each group. We had checked and obtained the vaccine with co-transfection of CEA gene and EPO gene by cell red line marker antibody CD71 and GPA, then we carried on experiments with the vaccine in vitro and in vivo. There were 4 groups in our trail: blank vector group, CEA group, EPO group, and CEA-EPO group. Results We had successfully gathered the hematopoietic stem cells, flow cytometry analysis result showed that there were significant differences before and after purification for positive selected samples (P<0.05). The expressions of double genes (CEA-EPO gene) and protein showed CEA-EPO gene were successfully transfected into the hematopoietic stem cells. We had confirmed erythrocyte vaccine with co-transfection of CEA and EPO gene by antibody CD71 and GPA with flow cytometry. The monocytes cytotoxicity on colon cancer cell line CT26 showed that lysis of target cells of CEA-EPO group were higher than those of other 3 groups when in proportion of 40∶1 (P<0.05). In the experimentation of neoplasma format, the volume of tumor and mortality were smaller or lower, but survival time was longer of CEA-EPO group in2 weeks after treatment (P<0.05). Conclusions The erythrocyte vaccine with co-transfection of CEA gene and EPO gene has efficient anti-tumor effects on colon cancer. Not only can promote hematopoietic stem cell directly producing erythrocyte vaccine, but also can produce tumor antigen vaccine against colon cancer.
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.
Objective To construct a bioengineered dermis containing microencapsulated nerve growth factor (NGF) expressing -NIH3T3 cells and to study the effect of the microencapsule on the bioengineered dermis and acute wound healing. Methods A recombinant NGF (PcDNA3.1+/NGF) was constructed and transfected intoNIH-3T3 cells using FuFENETM6 transfection reagent. Positive cell strain was cultured and enclosed in alginate-polylysine-alginate(APA) microcapsules in vitro. Bioengineered dermis was incorporated with NGF-expressing micorencapsules and human fibroblast cells as seed cells using tissue engineering method. The characteristics of the dermis were described by the content of Hydroxyproline(Hyp), HE staining. The content of NGF in the dermis culturing supernatant was measured by ELISA method. These bioengineered dermis were transplanted onto the acute circular full thickness excisional wounds on the dorsum of each swine to observe the rate of reepithelization and wound healing: NGFNIH3T3 microencapsulations(group A), NIH3T3 microencapsulations( group B), empty microencapsulations (group C), NGF incorporated with collagenⅠ( group D) and blank (group E as control group). Results NGF can be tested stably about 124.32 pg/ml in the dermis culturing supernatant after 6 weeks, and the content of Hyp in group A was 69.68±6.20(mg/g wet weight) and increased about 2 times when compared with control groups after 1 week. The tissue engineering skin grafts which can secrete NGF were used to ure the acute wounds and the rate of reepithelization was promoted. The periods of wound healing were 25±2 days in group A, 34±3 days in group B, 34±2 days in group C, 33±2 days in group D and 40±3 days in group E.The period of wound healing was decreased about 10 days at least. Conclusion NGF-expressing NIH3T3 microencapsulates can promote the quality of bioengineered dermis and alsopromote acute wound healing.
Objective To construct the recombined DNA pcDNA3.1-hBMP-2 and transfect into human marrow stromal stem cells (MSCs) in vitro, and to explore theeffects of transfection on cellular proliferation and expression of vascular endothelial growth factor (VEGF). Methods The expression of human bone morphogenetic protein 2(hBMP-2) in these cells after transfection was determined by in situ hybridization and immunohistochemical analysis and Western blot analysis. The changes of cell proliferation were observed by flow cytometry. The effects of BMP-2 gene transfection on expression of VEGF in the cells were analyzed by in situ hybridization of VEGF cDNA probe. Results Stable expressionof hBMP-2 in pcDNA3.1-hBMP-2 transfected MSCs was confirmed in the levels of mRNA and protein.Cellular proportion in S period increased, which indicated that the synthesis of cell DNA increased. The expression of VEGF in the cells increased obviously. Conclusion With the help of lipofectamine, the pcDNA3.1-hBMP-2 were transfected into human MSCs successfully. hBMP-2 plays an important role in promoting cellular proliferation and vascular generation during bone repair.
Objective To construct a recombinant adenovirus vector pAdxsi-GFP-NELL1 that co-expressing green fluorescent protein (GFP) and homo sapiens NEL-l ike 1 (NELL1) protein (a protein bly expressed in neural tissue encoding epidermal growth factor l ike domain), to observe its expression by transfecting the recombinant adenovirus into rat bone marrow mesenchymal stem cells (BMSCs) so as to lay a foundation for further study on osteogenesis of NELL1 protein. Methods From pcDNA3.1-NELL1, NELL1 gene sequence was obtained, then NELL1 gene was subcloned into pShuttle-GFP-CMV (-)TEMP vector which was subsequently digested with enzyme and insterted into pAdxsi vector to package the recombinant adenovirus vector (pAdxsi-GFP-NELL1). After verified by enzyme cutting and gel electrophoresis, pAdxsi-GFPNELL1 was ampl ified in HEK293 cells and purified by CsCl2 gradient purification, titrated using 50% tissue culture infective dose (TCID50) assay. The rat BMSCs were cultured and identified by flow cytometry and directional induction, then were infected with adenoviruses (pAdxsi-GFP-NELL1 and pAdxsi-GFP). NELL1 expression was verified by RT-PCR and immunofluorescence; GFP gene expression was verified by the intensity of green fluorescence under fluorescence microscope. Cell counting kit-8 (CCK-8) was used for investigate the influence of vectors on the prol iferation of rat BMSCs. Results Recombinant adenoviral vector pAdxsi-GFP-NELL1, which encodes a fusion protein of human NELL1, was successfully constructed and ampl ified with titer of 1 × 1011 pfu/mL. The primary BMSCs were cultured and identified by flow cytometric analysis, osteogenic and adipogenic induction, then were used for adenoviral transfection efficiency and cell toxicity tests. An multipl icity of infection of 200 pfu/cell produced optimal effects in transfer efficiency without excessive cell death in vitro. Three days after transfection with 200 pfu/cell pAdxsi-GFP-NELL1 or pAdxsi-GFP, over 60% BMSCs showed green fluorescent by fluorescence microscopy. Imunofluorescence with NELL1 antibody also revealed high level expression of human NELL1 protein in red fluorescent in these GFP expressing cells. RT-PCR analysis confirmed that the exogenous expression of NELL1 upon transfection with pAdxsi-GFPNELL1 at 200 pfu/cell, whereas NELL1 remained undetectable in Ad-GFP-transfected rat BMSCs. The prol iferative property of primary rat BMSCs after adenoviral NELL1 transfection was assayed by CCK-8 in growth medium. Growth curve demonstratedno significant difference among BMSCs transfected with pAdxsi-GFP-NELL1, pAdxsi-GFP, and no treatment control at 7 days (P gt; 0.05). Conclusion Recombinant adenovirus vector pAdxsi-GFP-NELL1 can steady expressing both GFP and NELL1 protein after being transfected into rat BMSCs. It provides a useful tool to trace the expression of NELL1 and investigate its function in vitro and in vivo.
The study was performed to construct a human cervical cancer cell line C33A which can stably express HPV58E6E7 fusion gene. Firstly, C33A cells were transfected with the recombinant lentivirus LV-HPV58E6E7 which contained HPV58E6E7 fusion gene, and the stably transfected cells (LV-HPV58E6E7/C33A) were screened out by flow cytometry. MTT was used to observe the growth of LV-HPV58E6E7/C33A cells and flow cytometry was carried out to detect the cell cycle. LV-HPV58E6E7/C33A cells were inoculated into the left armpits of nude mice. Then, the transcription and expression of HPV58E6E7 fusion gene was detected by qRT-PCR and Western blot, respectively. The results showed that HPV58E6E7 fusion gene can promote the proliferation of C33A cells. HPV58E6E7 fusion gene can be stably transcripted and expressed in vaccinated nude mice. The conclusion indicated that we successfully established a cervical cancer cell line LV-HPV58E6E7/C33A which can stably express HPV58E6E7 fusion gene. This cell line will provide an antigen cell line for the immune effect detection of HPV58 therapeutic vaccine.
ObjectiveTo construct and identify the recombinant adenovirus vector expressing bone morphogenetic protein 2(BMP-2) and transforming growth factor β3(TGF-β3) genes,to observe the expressions of BMP-2 and TGF-β3 after transfected into bone marrow mesenchymal stem cells (BMSCs) of the Diannan small-ear pigs. MethodsBMP-2 cDNA and TGF-β3 cDNA were amplified by PCR,and were subcloned into the pEC3.1(+) plasmid to obtain pEC-GIE 3.1-BMP-2 and pEC-GIE3.1-TGF-β3 plasmid respectively.They were subcloned into pGSadeno vector by homologous recombination reaction and HEK293 cells were transfected after linearization to obtain Ad-BMP-2 and Ad-TGF-β3.The BMSCs were isolated from the bone marrow of Diannan small-ear pig and cultured.The 3rd passage BMSCs were transfered with Ad-BMP-2(group A),Ad-TGF-β3(group B),Ad-BMP-2+Ad-TGF-β3(group C),and untransfected cells served as a control (group D).The expressions of BMP-2 and TGF-β3 genes and proteins were detected by PCR,immunofluorescence,and Western blot.The chondrogenic differentiation of BMSCs was evaluated by immunohistochemical of collagen type Ⅱ. ResultsThe Ad-BMP-2 and Ad-TGF-β3 were constructed successfully and confirmed by PCR and sequencing.The expression clones of Ad-BMP-2 and Ad-TGF-β3 were packaged into maturated adenovirus successfully,the titer was 5.6×108 and 1.6×108 pfu/mL respectively.The PCR results showed a light band at 310 bp in group A and at 114 bp in group B,and both 310 bp and 114 bp bands in group C,but no band in group D.The image of immunofluorescence showed that there were red fluorescence and green fluorescence expressions in the cytoplasm of BMSCs at 72 hours after transfection in groups A and B,respectively;in group C,both red and green fluorescence expressions were detected,and no red or green fluorescence was detected in group D.The results of Western blot showed that there was a light band at 18×103 in group A and at 50×103 in group B;both 18×103 and 50×103 bands were detected in group C;but no band was detected in group D.The cells were positive for collagen type Ⅱ in groups A,B,and C;group C acquired strong collagen type Ⅱ staining when compared with group A and group B;in group D,the cells were negative for collagen type Ⅱ staining. ConclusionThe recombinant adenovirus vector expressing BMP-2 and TGF-β3 are constructed successfully.The BMP-2 and TGF-β3 genes could be expressed effectively in BMSCs of Diannan small-ear pig after transfection,which could afford modified seeding cells for cartilage tissue engineering.
【Abstract】 Objective To review the research progress of possible mechanism of indoleamine 2, 3-dioxygenase(IDO) in immunological regulation and function of transplantation immunity. Methods The advances in the IDO location, immunological regulatory mechanism and function of transplantation immunity were introduced based on the recent related l iterature. Results IDO played an immunoregulatory role by locally depleting tryptophan in tissue microenvironment which resulted in immunosuppression of allogeneic T-cell prol iferation. IDO cDNA was del ivered to chromosome in interesting cells by gene transfection and stimulated to express, which was associated with a prolongation in allograft survival in vivo . Conc lu sion IDO offers a new way in transplantation immunity, and this provid novel method for elevating allograft survival rate.