Objective To construct recombinant lentiviral vectors of porcine bone morphogenetic protein 2 (BMP-2) gene and to detect BMP-2 gene activity and bone marrow mesenchymal stem cells (BMSCs) osteogenetic differentiation so as to lay a foundation of the further study of osteochondral tissue engineering. Methods BMSCs were isolated from bone marrow of 2-month-old Bama miniature porcines (weighing, 15 kg), and the 2nd generation of BMSCs were harvested for experiments. The porcine BMP-2 gene lentiviral vector was constructed by recombinant DNA technology and was used to transfect BMSCs at multiplicity of infection (MOI) of 10, 25, 50, 100, and 200, then the optimal value of MOI was determined by fluorescent microscope and inverted phase contrast microscope. BMSCs transfected by BMP-2 recombinant lentiviral vectors served as experimental group (BMP-2 vector group); BMSCs transfected by empty vector (empty vector group), and non-transfected BMSCs (non-transfection group) were used as control groups. RT-PCR, immunohistochemistry staining, and Western blot were performed to detect the expressions of BMP-2 mRNA and protein. Then the BMSCs osteogenesis was detected by alkaline phosphatase (ALP) staining, ALP activities, and Alizarin red staining. Results The recombinant lentiviral vectors of porcine BMP-2 gene was successfully constructed and identified by RT-PCR and gene sequencing, and BMSCs were successfully transfected by BMP-2 recombinant lentiviral vectors. Green fluorescent protein could be seen in the transfected BMSCs, especially at MOI of 100 with best expression. The immunohistochemistry staining and Western blot showed that BMSCs transfected by BMP-2 recombinant lentiviral vectors could express BMP-2 protein continuously and stably at a high level. After cultivation of 2 weeks, the expression of ALP and the form of calcium nodules were observed. Conclusion The porcine BMP- 2 gene lentiviral vector is successfully constructed and transfected into the BMSCs, which can express BMP-2 gene and protein continuously and stably at a high level and induce BMSCs differentiation into osteoblasts.
Objective To construct human recombinant lentiviral expression vector of microRNA-210 (miR-210)and to explore the over-expression of miR-210 on the capillary formation in human umbilical vein endothelial cells 12 (HUVE-12). Methods The recombinant lentiviral expression vector of pGCSIL-green fluorescent protein (GFP)-pre-miR-210 wasconstructed by molecular cloning and transfected to HUVE-12 (LV-miR-210-GFP group), only pGCSIL-GFP was transfectedas control group (LV-GFP group). The miR-210 expression activity was evaluated by GFP reporter through fluorescencedetection and real-time fluorescent quantitative PCR. The ephrinA3 protein expression was measured by flow cytometry. Theconcentration of vascular endothelial growth factor (VEGF) in culture supernatant was determined by ELISA. The cells werecultured in 96-well culture plate coated with Matrigel to assess the abil ity of capillary formation. Results The recombinantplasmid pGCSIL-GFP-pre-miR-210 was confirmed by restriction endonuclease analysis and DNA sequencing. Fluorescencedetection showed that the fluorescence intensity of GFP was highest between 48 and 72 hours after transfection. Real-timefluorescent quantitative PCR showed that the miR-210 expression of LV-miR-210-GFP group was 9.72 times higher than thatin LV-GFP group (t= —11.10，P=0.00). Flow cytometry analysis showed that the positive cell rate of enphrinA3 in LV-miR-210-GFP group (12.52% ± 0.67%) was significantly lower than that in LV-GFP group (73.22% ± 1.45%) (t= —66.12，P=0.00).The concentration of VEGF in supernatant in LV-miR-210-GFP group was significantly higher than that in LV-GFP group[(305.29 ± 16.52) pg/mL vs. (42.52 ± 3.11) pg/mL, t= —27.06，P=0.00]. In vitro capillary-l ike formation assay showed that thenumber of capillaries was significantly larger in LV-miR-210-GFP group than in LV-GFP group (17.33 ± 6.33 vs. 6.33 ± 2.33,t= —2.83，P=0.04). Conclusion The recombinant lentiviral expression vector of miR-210 is constructed successfully andHUVE-12 over-expressing miR-210 can significantly increase the capillary formation, which facil itates further study on themolecular functions of miR-210 in angiogenesis.
Objective To construct recombinant lentiviral expression vectors of porcine transforming growth factor β1 (TGF-β1) gene and transfect bone marrow mesenchymal stem cells (BMSCs) so as to provide TGF-β1 gene-modified BMSCs for bone and cartilage tissue engineering. Methods The TGF-β1 cDNA was extracted and packed into lentiviral vector, and positive clones were identified by PCR and gene sequencing, then the virus titer was determined. BMSCs were isolated frombone marrow of the 2-month-old Bama miniature pigs (weighing 15 kg), and the 2nd and 3rd generations of BMSCs wereharvested for experiments. BMSCs were then transfected by TGF-β1 recombinant lentiviral vectors (TGF-β1 vector group)respectively at multi pl icity of infection (MOI) of 10, 50, 70, 100, and 150; then the effects of transfection were detected bylaser confocal microscope and Western blot was used to determine the optimal value of MOI. BMSCs transfected by empty vector (empty vector group) and non-transfected BMSCs (non-transfection group) were used as control group. RT-PCR, immunocytochemistry, and ELISA were performed to detect the expressions of TGF-β1 mRNA, TGF-β1 protein, and collagen type II. Results Successful construction of recombinant lentiviral vectors of porcine TGF-β1 gene was identified by PCR and gene sequencing, and BMSCs were successfully transfected by TGF-β1 recombinant lentiviral vectors. Green fluorescence was observed by laser confocal microscope. Western blot showed the optimal value of MOI was 70. The expression of TGF-β1 mRNA was significantly higher in TGF-β1 vector group than in empty vector group and non-transfection group (P lt; 0.05). Immunocytochemistry results revealed positive expression of TGF-β1 protein and collagen type II in BMSCs of TGF-β1 vector group, but negative expression in empty vector group and non-transfection group. At 21 days after transfection, high expression of TGF-β1 protein still could be detected by ELISA in TGF-β1 vector group. Conclusion TGF-β1 gene can be successfully transfected into BMSCs via lentiviral vectors, and long-term stable expression of TGF-β1 protein can be observed, prompting BMSCs differentiation into chondrocytes.
Objective To construct the lentiviral vector to co-express enhanced green fluorescent protein (EGFP) gene and human insul in (insulin) gene, and to explore the condition to transfect human umbil ical cord mesenchymal stem cells (hUCMSCs) so as to lay a foundation for tissue engineered adipose reconstruction and transplantation in vivo infuture. Methods The insulin gene was cloned to lentiviral expression vector with EGFP [pLenti6.3-internal ribosome entrysite (IRES)-EGFP] by recombinant DNA technology, the positive clones were screened, and lentiviral packaged systems and target gene plasmid were co-transfected to package virus in 293T cells by lipofectin. The reporter gene expression was observed by fluorescent inverted phase contrast microscope, virus supernatant was collected, purificated and concentrated, and the titer of recombinant viruses was determinated. hUCMSCs from umbilical cord tissue of mature neonates were isolated and cultured by different multiple of infection (MOI, 0, 1, 3, 5, 7, 10, 15, and 20). By recombinant lentiviral infected hUCMSCs with reporter gene green fluorescent protein expression, the best MOI was screened; recombinant lentiviral infected hUCMSCs at the best MOI, then real-time PCR and Western blot methods were appl ied to detect insulin gene and insul in protein expression levels in cells. Results The recombinant lentiviral vector of co-expressing insulin gene and EGFP gene (pLenti6.3-insulin-IRESEGFP) was successfully constructed. Virus could be packaged, purificated and concentrated successfully. The virus titer was 1.3 × 108 TU/mL. The best MOI was 10 and the transfer efficiency was up to 90% in the same time. Real-time PCR results showed that insulin gene expression of transfected group was positive and non-transfected group was negative; Western blot detection confirmed that insul in protein expression of transfected group was positive in cells and supernatant, but that of non-transfected group was both negative. Conclusion Lentiviral vector pLenti6.3-insulin-IRES-EGFP carrying recombinant insulin gene could effectively transfect hUCMSCs and express insul in protein.
Objective To construct lentiviral vector carrying the human hepatocyte growth factor (hHGF) gene, and then to get hHGF gene/modified bone marrow mesenchymal stem cells (BMSCs) by infecting the BMSCs. Methods The hHGF gene was obtained with PCR from pcDNA-hHGF plasmid. The recombination lentiviral vector plasmid hHGF was constructed with Age I digestion and gene recombinant, then was identified with PCR and sequencing. Mediated by Lipofectamine2000, the three plasmids system of lentiviral vector including pGC-E1-hHGF, pHelper 1.0, and pHelper 2.0 was co-transfected to 293T cells to produce hHGF gene. The supernatant was collected and concentrated by ultracentrifugation and the titer of lentivirus was measured by real-time quantitative PCR. The BMSCs were infected by the constructed lentivirus and the multipl icities of infection (MOI) was identified with fluorescent microscope, the efficiency of infection with flow cytometry (FCM) analysis, the hHGF level with ELISA analysis, and the expression of hHGF gene with RT-PCR. Results Lentiviral vector carrying hHGF gene was constructed successfully. The titer of lentivirus was 1 × 108 TU/mL. The infection efficiency of BMSCs by hHGF lentiviral was high and reached 98% by FCM, and the best MOI was 10. A great mount of green fluorescence was observed with the fluorescent microscope at 28 days after infection. Peak concentration of hHGF secreted by BMSCs/hHGF reached 40.5 ng/mL at 5 days. The concentration could maintain a high level until 28 days after infection. RT-PCR showed that BMSCs/hHGF could express hHGF gene. Conclusion By lentiviral vector, hHGF gene was integrated into BMSCs genome, and it can express stably.
Objective To investigate a change in the differentiation and biological function of the cultured rat fibroblast (FB) transfected by the myoblast determining gene (MyoD) and the connexin 43 (Cx43) gene and to explore the possible mechanism of the MyoD and Cx43 genes on treatment of ischemic heart disease (IHD). Methods The gene cloning technology was used to construct the eukaryotic expressed plasmid vector pLenti6/V5-DEST-MyoD and pLenti6/V5DEST-Cx43 in which MyoD cDNA or Cx43 cDNA was inserted. The RFL-6 FB cells were transfected with exogenetic MyoD cDNA or Cx43 cDNA via lipofectamine, followed by the Blasticidin (50 μg/ml) selection, according to the lentiviral expression system (ViraPower) protocol. The expression and the biological functions of MyoD and Cx43 in the transfectants were testified by RT-PCR, Western blot, and molecular and immunocytochemical methods. The mophological structure changes of the cells were observed under microscope before and after the transfection. Results The expression of MyoD and Cx43 was detected in the MyoD and Cx43 genes transfected FB with RT-PCR and Western blot. The immunocytochemical methods indicated the expressionsof the MyoD and Cx43 genes, while desmin and αactin were found in these cells. The myotubes were found from the cultures incubated a week in the differentiation medium, in which the transfected cells had a characteristic of the filamentsin their cytoplasm and showed a myoblast morphology. Conclusion MyoD cDNA can induce the cultured FB to differentiate into the myoblasts and Cx43 cDNA can enhance the gap junctional intercellular communication between the cell and the cell. Thus, a further experimental foundation for the therapy of IHD can be provided.
ObjectiveTo build a lentiviral expression vector regulated by two targets 5 copies of HREs and hTERTp, express the target gene CDX2, and to test the activity of hTERT promoter by using LoVo cells for transfection. MethodsAfter the primer sets were designed, the hTERT promoter was cloned by PCR amplification from the genome of colon cancer. The CEA promoter was removed from the original vector pLEGFP-5HRE-CEAp by double digestion and PCR method, and then the hTERTp was introduced into the vector to construct the recombinant plasmid pLEGFP-5HRE-hTERTp. 5HRE-hTERTp was obtained by PCR, while the CMV promoter was removed from the original vector pLVX-EGFP-3FLAG by double digestion and PCR method, and then the 5HRE-hTERTp was introduced into the vector to construct the recombinant plasmid pLVX-5HRE-hTERTp-EGFP-3FLAG. The CDX2 was cloned by PCR amplification from GV230-CDX2-EGFP, and the EGFP was removed from the vector pLVX-5HRE-hTERTp-EGFP-3FLAG by double digestion, and then the CDX2 was introduced into the vector to construct the recombinant plasmid pLVX-5HRE-hTERTp-CDX2-3FLAG. LoVo cells ex vivo was transiently transfected by pLVX-5HRE-hTERTp-EGFP-3FLAG to evaluate the activity of hTERTp by detecting the expression of green fluorescence protein EGFP. ResultsPCR and sequencing analyzing showed that pLEGFP-5HRE-hTERTp, pLVX-5HRE-hTERTp-EGFP-3FLAG, and pLVX-5HRE-hTERTp-CDX2-3FLAG were sequenced correctly and the same as our designed. pLVX-5HRE-hTERTp-EGFP-3FLAG was successfully transfected into LoVo cells ex vivo and expressed green fluorescence protein EGFP, which showed that hTERTp was activated and promoted the expression of downstream gene. ConclusionThe lentiviral expression vector, pLVX-5HREhTERTp-EGFP-3FLAG and pLVX-5HRE-hTERTp-CDX2-3FLAG are successfully constructed, which lays the foundation of further research. But the function of dual-target regulation needs further proof.
ObjectiveTo observe the morphological and functional changes of retinal degeneration in mice with CLN7 neuronal ceroid-lipofuscinosis, and the therapeutic effects of glial cell derived neurotrophic factor (GDNF) and/or ciliary neurotrophic factor (CNTF) based on neural stem cells (NSC) on mouse photoreceptor cells. MethodsA total of 100 CLN7 mice aged 14 days were randomly divided into the experimental group and the control group, with 80 and 20 mice respectively. Twenty C57BL/6J mice aged 14 days were assigned as wild-type group (WT group). Mice in control group and WT group did not receive any interventions. At 2, 4, and 6 months of age, immunohistochemical staining was conducted to examine alterations in the distribution and quantity of cones, rod-bipolar cells, and cone-bipolar cells within the retinal of mice while electroretinography (ERG) examination was utilized to record scotopic a and b-waves and photopic b-wave amplitudes. At 14 days of age, the mice in the experimental group were intravitreally injected with 2 μl of CNTF-NSC, GDNF-NSC, and a 1:1 cell mixture of CNTF-NSC and GDNF-NSC (GDNF/CNTF-NSC). Those mice were then subdivided into the CNTF-NSC group, the GDNF-NSC group, and the GDNF/CNTF-NSC group accordingly. The contralateral eyes of the mice were injected with 2 μl of control NSC without neurotrophic factor (NTF) as their own control group. At 2 and 4 months of age, the rows of photoreceptor cells in mice was observed by immunohistochemical staining while ERG was performed to record amplitudes. At 4 months of age, the differentiation of grafted NSC and the expression of NTF were observed. Statistical comparisons between the groups were performed using a two-way ANOVA. ResultsCompared with WT group, the density of cones in the peripheral region of the control group at 2, 4 and 6 months of age (F=285.10), rod-bipolar cell density in central and peripheral retina (F=823.20, 346.20), cone-bipolar cell density (F=356.30, 210.60) and the scotopic amplitude of a and b waves (F=1 911.00, 387.10) in central and peripheral retina were significantly decreased, with statistical significance (P＜0.05). At the age of 4 and 6 months, the density of retinal cone cells (F=127.30) and b-wave photopic amplitude (F=51.13) in the control group were significantly decreased, and the difference was statistically significant (P＜0.05). Immunofluorescence microscopy showed that the NSC transplanted in the experimental group preferentially differentiated into astrocytes, and stably expressed CNTF and GDNF at high levels. Comparison of retinal photoreceptor nucleus lines in different treatment subgroups of the experimental group at different ages: CNTF-NSC group, at 2 months of age: the whole, central and peripheral regions were significantly different (F=31.73, 75.06, 75.06; P＜0.05); 4 months of age: The difference between the whole area and the peripheral region was statistically significant (F=12.27, 12.27; P＜0.05). GDNF/CNTF-NSC group, 2 and 4 months of age: the whole (F=27.26, 27.26) and the peripheral area (F=16.01, 13.55) were significantly different (P＜0.05). In GDNF-NSC group, there was no statistical significance at all in the whole, central and peripheral areas at different months of age (F=0.00, 0.01, 0.02; P＞0.05). ConclusionsCLN7 neuronal ceroid-lipofuscinosis mice exhibit progressively increasing degenerative alterations in photoreceptor cells and bipolar cells with age growing, aligning with both morphological and functional observations. Intravitreal administration of stem cell-based CNTF as well as GDNF/CNTF show therapeutic potential in rescuing photoreceptor cells. Nevertheless, the combined application of GDNF/CNTF-NSC do not demonstrate the anticipated synergistic protective effect. GDNF has no therapeutic effect on the retinal morphology and function in CLN7 neuronal ceroid-lipofuscinosis mice.