Objective To construct inducible lentiviral vector containing human bone morphogenetic protein 2 (hBMP-2) gene and to study its expression in human umbil ical cord blood mesenchymal stem cells (HUMSCs). Methods hBMP-2 gene was ampl ified by PCR from a plasmid and was cloned into pDown by BP reaction. pLV/EXPN2-Neo-TRE-hBMP-2 and pLV/EXPN2-Puro-EF1A-reverse transactivator (rtTA) were obtained with GATEWAY technology, and then were sequenced and analyzed by PCR. The recombinant vectors were transfected into 293FT cells respectively through l ipofectamine, and the lentiviral viruses were harvested from 293FT cells, then the titer was determined. Viruses were used to infect HUMSCs in tandem. In order to research the influence of induction time and concentration, one group of HUMSCs was induced by different doxycl ine concentrations (0, 10, 100 ng/mL, and 1, 10, 100 μg/mL) in the same induction time (48 hours), and the other by the same concentration (10 μg/mL) in different time points (12, 24, 48, and 72 hours). The expression of target gene hBMP-2 was indentified by ELISA method. After 2-week osteogenic induction of transfected HUMSCs, the mineral ization nodes were detected with Al izarin bordeaux staining method. Results Therecombinant inducible lentiviral vectors (pLV/EXPN2-Neo-TRE-hBMP-2 and pLV/EXPN2-Puro-EF1A-rtTA) were successfully constructed. The lentiviruses were also obtained and mediated by 293FT cells, and the virus titers were 3.5 × 108 TU/mL and 9.5 × 107 TU/mL respectively. HUMSCs could expression hBMP-2 by induction of doxycycl ine. The expression of hBMP-2 reached the peak at 10 μg/mL doxycl ine at 48 hours of induction. After 2-week osteogenic induction, a lot of mineral ization nodes were observed. Conclusion The recombinant inducible lentiviral vectors containing hBMP-2 gene can be successfully constructed, which provide an effective and simple method for the further study of stem cells and animal experiment in vivo.
OBJECTIVE: To conduct the in vitro test on drug release of rifampin encapsulated in a carrier made of porous phosphate glass ceramics and to analyze main factors which affect the drug release rate. METHODS: A certain quantitative of rifampin was sealed in a hollow cylindrical capsule which consisted of chopped calcium phosphate crystal fiber obtained from glass crystallization. The rifampin concentration was measured in the simulated physiological solution in which the capsule soaked. RESULTS: Rifampin could be released in a constant rate from the porous glass ceramic carrier in a long time. The release rate was dependent on the size of crystal fiber and the wall thickness of the capsule. CONCLUSION: This kind of calcium phosphate glass ceramics can be a candidate of the carrier materials used as long term drug therapy after osteotomy surgery.
Mesenchymal stem cells (MSCs) are considered as an ideal treatment for multiple diseases including ocular disease. Recent studies have demonstrated that MSCs-derived exosomes have similar functions with MSCs. Exosomes are nanovesicles surrounded by a phospholipid layer that shuttle active cargo between different cells. They are capable of passing the biological barrier and have potentials to be utilized as natural carrier for the ocular drug delivery.
Objective To study the biological activity of recombinant adeno-associated virus vector (rAAV) coexpressing human vascular endothel ial growth factor165 (hVEGF165) and human bone morphogenetic protein 7 (hBMP-7) genes in vitro so as to provide a new method for the therapeutics of osteonecrosis. Methods The 3rd passage rabbit bone marrow mesenchymal stem cells (BMSCs) were transfected with rAAV-hVEGF165-internal ribosome entry site (IRES)-hBMP-7(experimental group) and green fluorescent protein (GFP) labeled rAAV-IRES-GFP (control group). The expressions ofhVEGF165 and hBMP-7 were detected by ELISA assay at the 1st, 2nd, 3rd, 7th, 14th days and Western blot assay at the14th day after transfection. The expression consistencies of hVEGF165 and hBMP-7 were observed by immunofluorescence assay at the 14th day after transfection. The biological activity of hVEGF165 was assessed by angiopoiesis experiment of the 3rd passage human umbil ical vein endothel ial cells (HUVEC). The biological activity of hBMP-7 was assessed by mineral ization of BMSCs detected by ALP staining and al izarin red staining. Results With infecting time, the hVEGF165 and hBMP-7 expressions increased gradually in two groups, showing significant difference between two groups (P lt; 0.05). The expressions of hVEGF165 and hBMP-7 were positive in experimental group and negative in control group, respectively. Immunofluorescence assay showed positive expressions of hVEGF165 and hBMP-7 in the exprimental group and negative expression in the control group, the expression of hVEGF165 and hBMP-7 had good consistencies. hVEGF165 secreted from BMSCs enhanced HUVEC migration, prol iferation and tube formation in experimental group. There was significant difference in the number of blood vessel between two groups (P lt; 0.05). The ALP staining showed more bly stained granules in experimental group than in control group. There was significant difference in the number of the mineral ized nodules between two groups (P lt; 0.05). Conclusion The rAAV-hVEGF165-IRES-hBMP-7 has good biological activity in vitro.
【 Abstract】 Objective To construct a lentiviral expression vector carrying Nogo extra cellular peptide residues 1-40(NEP1-40) and to obtain NEP1-40 efficient and stable expression in mammalian cells. Methods The DNA fragment ofNEP1-40 coding sequence was ampl ified by PCR with designed primer from the cDNA l ibrary including NEP1-40 gene, and then subcloned into pGC-FU vector with in-fusion technique to generate the lentiviral expression vector, pGC-FU-NEP1-40. The positive clones were screened by PCR and the correct NEP1-40 was confirmed by sequencing. Recombinant lentiviruses were produced in 293T cells after the cotransfection of pGC-FU-NEP1-40， and packaging plasmids of pHelper 1.0 and pHelper 2.0. Green fluorescent protein (GFP) expression of infected 293T cells was observed to evaluate gene del ivery efficiency. NEP1-40 protein expression in 293T cells was detected by Western blot. Results The lentiviral expression vector carrying NEP1-40 was successfully constructed by GFP observation， and NEP1-40 protein expression was detected in 293T cells by Western blot. Conclusion The recombinant lentivirus pGC-FU-NEP1-40 is successfully constructed and it lays a foundation for further molecular function study of NEP1-40.
Objective To investigate the neuroprotective effects of recombinant adeno-associated virus (rAAV) expressing vascular endothel ial growth factor (VEGF) on traumatic spinal cord injury (SCI) of rat and its mechanisms. Methods The 144 male Sprague Dawley rats were randomly divided into 4 groups, and each group contained 36 rats. The rats in sham group (group A) received dorsal laminectomy without SCI and microinjection, the rats in model control group (group B), rAAV-green fluorescent protein (GFP) group (group C), and rAAV-hVEGF165-GFP group (group D) received dorsallaminectomy with SCI and injection of 20 μL sal ine, rAAV-GFP viruses, or rAAV-hVEGF165-GFP viruses, respectively. At 3 and 7 days after operation, Basso-Beattie-Bresnahan (BBB) score was used to evaluate the neurologic function. At 7 days after operation, Nissl’s body staining was used to evaluate the histopathological changes; apoptosis was confirmed by transmission electron microscope examination and TUNEL staining; the expression of aquaporin 4 (AQP-4) was detected by Western blot assay. At 1, 3, 5, and 7 days, ELISA assay was used to detect the VEGF165 protein expression. Results According to BBB scores, the neurologic function in group D was significantly better than those in groups B and C at 3 and 7 days after operation (P lt; 0.05). Nissl’s body staining showed that tissue damage in group D was significantly milder than those in groups B and C at 7 days after operation (P lt; 0.05). ELISA results showed that VEGF165 protein expression was slowly-released in low dose in group D, and the expression in group D was significantly higher than that in groups A, B, and C at 3, 5, and 7 days after operation (P lt; 0.05). The results of transmission electron microscope and TUNEL staining showed that apoptosis rate of spinal cord neurons in group D was significantly lower than that in groups B and C at 7 days after operation (P lt; 0.05). The results of Western blot showed that AQP-4 expression in group D was significantly decreased when compared with that in groups B and C at 7 days after operation (P lt; 0.05). Conclusion TherAAV expressing VEGF has neuroprotective effects by inhibiting apoptosis of spinal cord neurons and relieving spinal cord edema.
Abstract： Objective To construct a nesprin-siRNA lentiviral vector（LV-siNesprin）, transfect it into bone marrow mesenchymal stem cells （MSCs）, and observe morphology changes of MSCs. Methods According to the target gene sequence of nesprin, we designed and synthesized four pairs of miRNA oligo, which were then annealed into double-strand DNA and identified by sequencing. MiRNA interference with the four kinds of plasmids （SR-1,SR-2,SR-3, andSR-4） were transfected into rat vascular smooth muscle cells, and reverse transcriptase chain reaction(RT-PCR) and Western blotting were performed to detect the interference effects and filter out the most effective interference sequence. We used the best interference sequence carriers and pDONR221 to react together to get the entry vectors with interference sequence. Then the objective carrier pLenti6/V5-DEST expressing both entry vectors and lentiviral vectors was restructured to get lentiviral expression vector containing interference sequence （LV-siNesprin＋green fluoresent protein （GFP））, which was packaged and the virus titer was determined. LV-siNesprin＋GFP was transfected to MSCs, and the expression of nesprin protein（LV-siNesprin＋GFP group，GFP control group and normal cell group）was detected by Western blotting. The morphology of MSCs nuclear was observed by 4’,6-diamidino-2-phenylindole （DAPI） stain. The proliferation of MSCs （LV-siNesprin＋GFP group，GFP control group and normal group） was detected by 3-(4,5-dimethylthia- zol-2-yl)-2,5-diphenyltetrazolium bromide（MTT） after lentivirus transfected to MSCs at 24, 48, 72, and 96 hours. Results The four pairs of miRNA oligo were confirmed by sequencing. Successful construction of LV-siNesprin was confirmed by sequencing. The best interference with miRNA plasmid selected by RT-PCR and Western blotting was SR-3. Lentiviral was packaged, and the activity of the virus titer of the concentrated suspension was 1×106 ifu/ml. After MSCs were transfected with LV-siNesprin, nesprin protein expression significantly decreased, and the nuclear morphology also changed including fusion and fragmentation. The proliferation rate of MSCs in the LV-siNesprin＋GFP group was significantly slower than that of the GFP control and normal cell groups by MTT. Conclusion Nesprin protein plays an important role in stabilizing MSCs nuclear membrane, maintaining spatial structure of MSCs nuclear membrane，and facilitating MSCs proliferation.
【Abstract】 Objective To produce a new bone tissue engineered carrier through combination of xenograft bone (X)and sodium alginate (A) and to investigate the biological character of the cells in the carrier and the abil ity of bone-forming in vivo, so as to provide experimental evidence for a more effective carrier. Methods BMSCs were extracted from 2-week-old New Zealand rabbits and the BMSCs were induced by rhBMP-2 (1 × 10-8mol/L). The second generation of the induced BMSCs was combined with 1% (V/W) A by final concentration of 1 × 105/mL. After 4-day culture, cells in gel were investigated by HE staining. The second generation of the induced BMSCs was divided into the DMEM gel group and the DMEM containing 1% A group. They were seeded into 48 well-cultivated cell clusters by final concentration of 1 × 105/mL. Seven days later, the BMP-2 expressions of BMSCs in A and in commonly-cultivated cells were compared. The second generation of the induced BMSCs was mixed with 2% A DMEM at a final concentration of 1 × 1010/mL. Then it was compounded with the no antigen X under negativepressure. After 4 days, cells growth was observed under SEM. Twenty-four nude mice were randomly divided into 2 group s (n=12).The compound of BMSCs-A-X (experimental group) and BMSCs-X (control group) with BMSCs whose final concentrat ion was 1 × 1010/mL was implanted in muscles of nude mice. Bone formation of the compound was histologically evaluated by Image Analysis System 2 and 4 weeks after the operation, respectively. Results Cells suspended in A and grew plump. Cell division and nuclear fission were found. Under the microscope, normal prol iferation, many forming processes, larger nucleus, clear nucleolus and more nuclear fission could be seen. BMP-2 expression in the DMEM gel group was 44.10% ± 3.02% and in the DMEM containing 1% A group was 42.40% ± 4.83%. There was no statistically significant difference between the two groups (P gt; 0.05). A was compounded evenly in the micropore of X and cells suspended in A 3-dimensionally with matrix secretion. At 2 weeks after the implantation, according to Image Analysis System, the compound of BMSCs-A-X was 5.26% ± 0.24% of the totalarea and the cartilage-l ike tissue was 7.31% ± 0.32% in the experimental group; the compound of BMSCs-X was 2.16% ± 0.22% of the total area and the cartilage-l ike tissue was 2.31% ± 0.21% in the control group. There was statistically significant difference between the two groups (P lt; 0.05). At 4 weeks after the operation, the compound of BMSCs-A-X was 7.26% ± 0.26% of the total area and the cartilage-l ike tissue was 9.31% ± 0.31% in the experimental group; the compound of BMSCs-X was 2.26% ± 0.28% of the total area and the cartilage-l ike tissue was 3.31% ± 0.26% in the control group. There was statistically significant difference between the two groups (P lt; 0.05). Conclusion The new carrier compounding A and no antigen X conforms to the superstructural principle of tissue engineering, with maximum cells load. BMSCs behave well in the compound carrier with efficient bone formation in vivo.
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.
With the advancement of molecular biology technology and the development of genetics, the viral vector system has been continuously improved and optimized. The viral vector system has gradually become one of the best carriers in ophthalmic gene therapy. Adenovirus vector has the characteristics of transient expression and plays an important role in reducing corneal immune response. Lentiviral vector has the characteristics of stable and high efficiency and can be expressed slowly in the body for a long time.Adeno-associated virus vector has the characteristics of low immunogenicity, high efficiency and precision and can infect a variety of retinal cells. The combined use of adeno-associated virus vector and CRISPR-Cas9 provides new methods for precise treatment of ophthalmic genetic diseases. The advent of viral vectors has significantly increased the potential of gene therapy and has unparalleled advantages over traditional therapies. We have reason to believe that virus-based gene transduction technology will soon achieve clinical application in the near future, and a large number of difficult ophthalmic problems will be solved by then.