Single Nucleotide Polymorphisms Mutation of Tropoelastin Gene Affects Tropoelastin mRNA and Elastin Expressions in Human Aortic Smooth Muscle Cells.

We aimed to explore the effects of single nucleotide polymorphisms (SNPs) in tropoelastin gene on tropoelastin mRNA and elastin expressions in human aortic smooth muscle cells (HASMCs). Two SNP loci, rs2071307 (G/A) and rs1785598 (G/C), were selected to construct recombinant lentivirus vectors carrying wild-type and mutant tropoelastin gene. Recombinant plasmids including pWSLV-02-ELN, pWSLV-02-ELN-mut1, and pWSLV-02-ELN-mut2 were constructed, before being amplified by polymerase chain reaction (PCR) and sequenced. The prepared plasmids and the packaging plasmids (pVSV-G and psPAX2) were cotransfected into HEK293T cells to obtain recombinant lentiviruses carrying tropoelastin gene. Afterward, HASMCs were infected with recombinant lentiviruses, and the positive cells sorted by flow cytometry were amplified. Four stable HASMCs cell lines including pWSLV-02-ELN, pWSLV-02-ELN-mut1, pWSLV-02-ELN-mut2, and pWSLV-02 vector were constructed. The expressions of tropoelastin mRNA and elastin in HASMCs were detected by real-time quantitative reverse transcription-PCR and western blot, respectively. Recombinant plasmids including pWSLV-02-ELN-mut1, pWSLV-02-ELN-mut2, and pWSLV-02-ELN were successfully constructed. Recombinant lentiviruses carrying tropoelastin gene were obtained via lentivirus packaging. After infection for 24 h, 3 days and 5 days in HASMCs, tropoelastin mRNA expressions in pWSLV-02-ELN-mut1 and pWSLV-02-ELN-mut2 groups were significantly lower than that of pWSLV-02-ELN group. Besides, after infection for 24 h, 3 days, and 5 days, elastin levels in pWSLV-02-ELN-mut1 and pWSLV-02-ELN-mut2 groups were significantly lower than that in pWSLV-02-ELN group. In conclusion, SNPs mutation of tropoelastin gene affected the expression of tropoelastin mRNA and elastin, suggesting that the polymorphisms of rs2071307 and rs17855988 in tropoelastin gene might be important factors for AD development.

An Overview of Gene Editing Modalities and Related Non-clinical Testing Considerations.

Gene therapy has become an important modality for a wide range of therapeutic indications with a rapid increase in the number of therapeutic candidates being developed in this field. Understanding the molecular biology underlying the gene therapy is often critical to develop appropriate safety assessment strategies. We aimed to discuss some of the commonly used gene therapy modalities and common preclinical toxicology testing considerations when developing gene therapies. Non-viral gene delivery methods such as electroporation, microinjection, peptide nanoparticles and lipid nanoparticles are deployed as innovative molecular molecular construct which are included in the design of novel gene therapies and the associated molecular biology mechanisms have become relevant knowledge to non-clinical toxicology. Viral gene delivery methodologies including Adenovirus vectors, Adeno-Associated virus vectors and Lentivirus gene therapy vectors have also advanced considerably across numerous therapeutic areas, raising unique non-clinical toxicology and immunological considerations. General toxicology, biodistribution and tumorigenicity are the pillars of non-clinical safety testing in gene therapies. Evaluating the tumorigenicity potential of a gene editing therapy often leverages molecular pathology while some translational challenges remain. Toxicology study design is entering a new era where science-driven customized approaches and program specific considerations have become the norm.

Dendritic cells modified by tumor associated antigen SMP30 have enhanced antitumor effect against mouse hepatocarcinoma cells in vitro and in vivo.

OBJECTIVES: Tumor immunotherapy based on dendritic cells (DC) is one of the most promising approaches to treat cancers. This therapy uses an immunogenic tumor antigen to present it to T cells. Senescence marker protein 30 (SMP30) is identified as a tumor associated antigen (TAA) with high immunogenicity and specificity for hepatocellular carcinoma (HCC). DCs are the most potent antigen presenting cells, and can be transduced with tumor antigens to enhance antitumor immune response. The purpose of this study was to investigate the antitumor effect of DCs transduced with a recombinant lentiviral vector (LV-SMP30) expressing SMP30. METHODS: A recombinant lentiviral vector (LV-SMP30) expressing SMP30 was constructed and transduced into DCs. The expression of SMP30 was detected by western blot. Mouse bone marrow-derived DCs were divided into four groups: LV-SMP30 group (transduced with LV-SMP30), Protein group (co-cultured with SMP30 protein), LV group (transduced with the empty vector) and Untreated group (the normal DCs). The effect of LV-SMP30 on DCs was detected through surface markers (CD123, CD11c, CD80 and CD86) and cytokine production. The activation and proliferation of CD3+CD8+ T cells were detected by CCK-8 kit. Flow cytometry was used to detect CD3+CD8+ T cell-mediated cytotoxicity. After construction of a mouse subcutaneous xenograft model, the volume and growth of tumors in different groups were observed. The changes in serum immune indexes in the treated groups were compared with those in the control group. RESULTS: The LV-SMP30 recombinant was constructed and transduced into DCs successfully, and LV-SMP30-transduced DCs stably expressed SMP30. The percentages of expression in the LV-SMP30 and Protein groups were significantly higher than those in the LV or Untreated groups (P<0.05). Meanwhile, after the DCs were cultured for 72 hours, the levels of IL-2, IL-6, IL-12, and IFN-γ were significantly higher in the LV-SMP30 and Protein groups than in the LV group or Untreated group (P<0.05). After the DCs were continuously cultured for one week, however, the cytokine levels in the LV-SMP30 group were significantly higher than those in the Protein group (P<0.05). In addition, CD3+CD8+ T cell proliferation and activation levels were substantially higher in the LV-SMP30 and Protein groups than in the LV or Untreated groups (P<0.05). Furthermore, as the ratio of effectors/target cells increasing in the LV-SMP30 group, CD3+CD8+ T cell-mediated cytotoxicity in H22 cells became higher (0:1, 10:1; 20:1; 40:1, respectively). In comparison to the control group, the cytotoxicity of the LV-SMP30 group was considerably increased at the ratios of 10:1, 20:1 and 40:1 (P<0.05). However, in the case of Hep1-6 cells, there was no significant difference in CD3+CD8+ T cell-mediated cytotoxicity among the groups. In addition, when compared with other groups, the mice in the LV-SMP30 group showed the most volume reduction, the slowest tumor growth, and the highest level of IL-2 and IFN-γ (P<0.05). CONCLUSION: DCs transduced with LV-SMP30 can dramatically enhance specific CD3+CD8+ T cell immune responses against mouse hepatocarcinoma cells in vitro and in vivo. These findings lend significant support to the development of the DC-based SMP30 antigen vaccine for hepatocarcinoma immunotherapy.

[Construction and application of lentivirus overexpression vector with two labeling genes fused with CopGFP and PuroR].

Objective: To construct the lentivirus overexpression vector with two label genes fused with CopGFP and PuroR and to detect the emission of green fluorescence as well as resistance to puromycin in liver cancer cells infected with lentivirus packaged with the above vector. Methods: Firstly, two fragments containing copGFP and PuroR coding sequences were amplified from pCDH-CMV-MCS-copGFP and pLKO.1 respectively; secondly, the two amplified regions were fused with each other by recombinant PCR; thirdly, the fusion DNA fragment was cut and inserted into pCDH-CMV-MCS-copGFP vector, which was linearized with the same restriction endonuclease as used to digest fusion DNA fragment: BamH Ⅰ and Sal Ⅰ. The fusion region in the constructed vector was confirmed by DNA sequencing. The checked vector was co-transfected with package assistant plasmids, namely PLP1, PLP2 and VSVG into in 293T cells and the culture supernatant was subjected to centrifuge and infect liver cancer MHCC97H cells, which were then used to detect their resistance to puromycin (infected cells were treated with 1 mg/ml puromycin for 7 days after infection) and to observe green fluorescence emission in microscope. To determine its efficiency in expressing foreign target protein, the Sp1 coding region was inserted into the MCS sites of the vector, and Sp1 mRNA and protein expression levels were compared with the vehicle vector by RT-qPCR and Western blot. Results: The lentivirus overexpression vector with two label genes fused with CopGFP and PuroR was successfully constructed, and the liver cancer cells infected with lentivirus packaged with the vector expressing two labeling genes fused with CopGFP and PuroRshowed both emission of green fluorescence and resistance to puromycin simultaneously, while cells containing with the vector inserted with Sp1 coding region improved Sp1 mRNA level with 3.3 fold and protein level with 2.2 fold higher in comparison with cells containing the vehicle vector (P＜0.01). Conclusion: The fused label genes consisting of copGFP and PuroR are correctly cloned into the lentivirus vector and confer cells with the ability to emission of green fluorescence and resistance to puromycin, besides, the vector may promote the expression of the target gene with long coding sequence.

Recombinant jurkat cells (HMGN2-T cells) secrete cytokines and inhibit the growth of tumor cells.

High Mobility Group Chromosomal Protein N2 (HMGN2) can recognize tumor cells and enhance the anti-tumor effect of immune cells. This study aimed to establish a lentiviral vector of recombinant HMGN2 gene, establish recombinant T cells (HMGN2-T cells), and observe their anti-tumor effects. Total RNA was isolated from peripheral blood mononuclear cells. HMGN2, cluster of differentiation (CD) 8 A, CD28, CD137, and CD3ζ genes were amplified and connected. Jurkat cells were transfected with the recombinant lentivirus vector. The viability, apoptosis, and cell cycle of HMGN2-T cells were detected using Cell Counting Kit-8 assay and flow cytometry. The co-culture was performed by adding HMGN2-T cells to tumor cells with different effect-to-target (E:T) ratios. The cytotoxic activity was measured by lactate dehydrogenase (LDH) releasing assay. The sequences of HMGN2, CD8A, CD28, CD137, and CD3ζ gene plasmids were confirmed using gene sequencing. After the lentiviral transfection for 72 h, green fluorescence cells (HMGN2-T cells) could be seen. Cell viability and apoptosis were increased in HMGN2-T cells. The cytokine levels of interleukin 2 (IL-2) and tumor necrosis factor α (TNF-α) increased in cell supernatants of HMGN2-T cells. The percentage of G0/G1 phase cells was lower, the rate of S phase cells was higher in HMGN2-T cells than control cells. The co-culture of HMGN2-T cells and tumor cells could promote the cytokines' release. The LDH level was increased with the elevation of E:T ratios. In conclusion, the HMGN2-T cells were well-established and have the effect of secreting cytokines and killing tumor cells.

Generation of CAR-T Cells by Lentiviral Transduction.

CAR-T cell therapy is one of the most successful cell-based therapies. T cells are the most common cells to be genetically modified for cancer therapy, not only because T cells have cytotoxicity but also because they are easily cultured ex vivo and genetically modified with viral vectors. Hence, for nonexperts, T cell engineering is an ideal starting point for mammalian cell engineering or for development of therapeutics. Here, we have described a basic procedure for lentiviral transduction of human primary T cells to generate a CAR-T cell and assays to confirm CAR expression and function.

Lentivirus vector­mediated genetic manipulation of oncogenic pathways induces tumor formation in rabbit brain.

Translation of promising experimental therapies from rodent models to clinical success has been complicated as the novel therapies often fail in clinical trials. Existing rodent glioma models generally do not allow for preclinical evaluation of the efficiency of novel therapies in combination with surgical resection. Therefore, the aim of the present study was to develop a larger animal model utilizing lentivirus vector­mediated oncogenic transformation in the rabbit brain. Lentiviruses carrying constitutively active AKT and H­Ras oncogenes, and p53 small interfering (si)RNA were introduced into newborn rabbit neural stem cells (NSCs) and intracranially implanted into rabbits' brains to initiate tumor formation. In one of the ten rabbits a tumor was detected 48 days after the implantation of transduced NSCs. Histological features of the tumor mimic was similar to a benign Grade II ganglioglioma. Immunostaining demonstrated that the tissues were positive for AKT and H­Ras. Strong expression of GFAP and Ki­67 was also detected. Additionally, p53 expression was notably lower in the tumor area. The implantation of AKT, H­Ras and p53 siRNA transduced NSCs for tumor induction resulted in ganglioglioma formation. Despite the low frequency of tumor formation, this preliminary data provided a proof of principle that lentivirus vectors carrying oncogenes can be used for the generation of brain tumors in rabbits. Moreover, these results offer noteworthy insights into the pathogenesis of a rare brain tumor, ganglioglioma.

Efficient engraftment of genetically modified cells is necessary to ameliorate central nervous system involvement of murine model of mucopolysaccharidosis type II by hematopoietic stem cell targeted gene therapy.

Mucopolysaccharidosis type II (MPS II) is a lysosomal storage disease (LSD) caused by a deficiency of the iduronate-2-sulfatase (IDS) that catabolizes glycosaminoglycans (GAGs). Abnormal accumulations of GAGs in somatic cells lead to various manifestations including central nervous system (CNS) disease. Enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT) are the currently available therapy for MPS II, but both therapies fail to improve CNS manifestations. We previously showed that hematopoietic stem cell targeted gene therapy (HSC-GT) with lethal irradiation improved CNS involvement in a murine model of MPS II which lacks the gene coding for IDS. However, the strong preconditioning, with lethal irradiation, would cause a high rate of morbidity and mortality. Therefore, we tested milder preconditioning procedures with either low dose irradiation or low dose irradiation plus an anti c-kit monoclonal antibody (ACK2) to assess CNS effects in mice with MPS II after HSC-GT. Mice from all the HSC-GT groups displayed super-physiological levels of IDS enzyme activity and robust reduction of abnormally accumulated GAGs to the wild type mice levels in peripheral organs. However, only the mice treated with lethal irradiation showed significant cognitive function improvement as well as IDS elevation and GAG reduction in the brain. These results suggest that an efficient engraftment of genetically modified cells for HSC-GT requires strong preconditioning to ameliorate CNS involvement in cases with MPS II.

Efficient Nuclease-Directed Integration of Lentivirus Vectors into the Human Ribosomal DNA Locus.

Lentivirus vectors (LVs) are efficient tools for gene transfer, but the non-specific nature of transgene integration by the viral integration machinery carries an inherent risk for genotoxicity. We modified the integration machinery of LVs and harnessed the cellular DNA double-strand break repair machinery to integrate transgenes into ribosomal DNA, a promising genomic safe-harbor site for transgenes. LVs carrying modified I-PpoI-derived homing endonuclease proteins were characterized in detail, and we found that at least 21% of all integration sites localized to ribosomal DNA when LV transduction was coupled to target DNA cleavage. In addition to the primary sequence recognized by the endonuclease, integration was also enriched in chromatin domains topologically associated with nucleoli, which contain the targeted ribosome RNA genes. Targeting of this highly repetitive region for integration was not associated with detectable DNA deletions or negative impacts on cell health in transduced primary human T cells. The modified LVs characterized here have an overall lower risk for insertional mutagenesis than regular LVs and can thus improve the safety of gene and cellular therapy.

Construction of SIRT1 gene shRNA lentivirus vector and its effect on the proliferation of breast cancer cells.

Current experiment aimed to investigate the construction of the SIRT1 gene shRNA lentivirus vector and its effect on proliferation of breast cancer cells. Altogether 80 cases of breast cancer tissues and 80 cases of normal adjacent tissues were collected. qPCR was used for detecting SIRT1 expression. Western blot was used to detect the expression of EMT marker protein. The effect of lentivirus infected sh-SIRT1 on the cell biological function of SK-BR-3 and MDA-MB-231 cells was detected. MTT assay was used to detect cell activity, Transwell cell was used to detect cell invasion and migration, and cell apoptosis detected by flow cytometry. Compared with normal tissues adjacent to cancer, the expression of SIRT1 in cancer tissues increased significantly. Compared with human breast epithelial cells (MCF 10A), SIRT1 expression in breast cancer cells (MDA-MB-231, SK-BR-3) increased significantly. The above results showed that SIRT1 was significant greatly expressed in breast cancer. Compared with the sh-Control group, the cell activity, invasion and migration of the sh-SIRT1 group were enhanced, while cell apoptosis was weakened. In the sh-SIRT1 group infected by lentivirus, cell activity, cell invasion and migration decreased, while cell apoptosis increased. Compared with sh-Control, the expression of α-catenin, PTEN and E-cadherin in the sh-SIRT1 group in SK-BR-3 and MDA-MB-231 cells was down-regulated, while the expression of N- cadherin, ß-catenin and Vimentin was up-regulated. Compared with sh-Control, the expression of α-catenin, PTEN and E-cadherin in the sh-SIRT1 group infected by lentivirus was up-regulated, while the expression of N- cadherin, ß-catenin and Vimentin was down-regulated. To sum up, SIRT1 is highly expressed in breast cancer cells. The proliferation of breast cancer cells was inhibited after lentivirus infection with sh-SIRT1.

Preclinical Development and Clinical-Scale Manufacturing of HIV Gag-Specific, LentivirusModified CD4 T Cells for HIV Functional Cure.

Activation, infection, and eventual depletion of human immunodeficiency virus (HIV)-specific cluster of differentiation 4 (CD4) T cells are the crucial pathogenetic events in acquired immunodeficiency syndrome (AIDS). We developed a cell and gene therapy to reconstitute HIV-specific CD4 T cells and prevent their destruction by HIV. Antigen-specific CD4 T cells will provide helper functions to support antiviral cytotoxic T lymphocyte (CTL) function and the production of virus-specific antibodies. However, ex vivo expansion of HIV-specific CD4 T cells is poor and previous gene therapies focused on bulk CD4 T cells without enriching for an antigen-specific subset. We developed a method for manufacturing autologous CD4+ T cell products highly enriched with Gag-specific T cells. Rare Gag-specific CD4 T cells in peripheral blood mononuclear cells (PBMCs) were increased nearly 1,000-fold by stimulating PBMC with Gag peptides, followed by depleting nontarget cells and transducing with lentivirus vector AGT103 to protect against HIV-mediated depletion and inhibit HIV release from latently infected cells. The average percentage of HIV-specific CD4 cells in the final products was 15.13%, and the average yield was 7 × 108 cells. The protocol for clinical-scale manufacturing of HIV-specific and HIV-resistant CD4 T cells is an important step toward effective immunotherapy for HIV disease.

Construction of RHBDF2 gene over-expression lentivirus vector and establishment of RHBDF2 cell line stably expressing RHBDF2 / 吉林大学学报(医学版)

Objective: To construct the RHBDF2 gene over-expression lentivirus vector and to establish the KA. hy926 cells stably expressing RHBDF2, and to provide the evidence for the construction of RHBDF2 gene over-expression lentivirus vector and the establishment of RHBDF2 cells stably expressing RHBDF2. Methods: According to the sequence of RHBDF2 gene provided by NCBI, and the primers were designed and synthesized; the RHBDF2 gene was amplified by PCR method, and the target gene was cloned into the entry vector by Gateway cloning technology, and then subcloned into the lentivirus vector pLV [Exp]-EGFP to construct the recombinant lentivirus plasmid pLV I Exp]-EGFP-RHBDF2; the lentivirus expression vector plasmid pLV I Exp]-EGFP and the recombinant lentivirus plasmid pLV I Exp]-EGFP-RHBDF2 were co-transfected into the HEK293T cells with the virus-assisted packaging plasmids to package the lentivirus and the titer of the lentivirus was detected. The EA. hy926 cells infected with pLV [Exp]-EGFP-control were used as control group and the EA. hy926 cells infected with pLV [Exp]-EGFP-RHBDF2 were used as experiment group. The EA. hy926 cells stably expressing RHBDF2 were screened by puromycin. The fluorescent quantitative PCR (qPCR) and Western blotting methods were used to detect the expression levels of RHBDF2 mRNA and protein in the EA. hy926 cells in control group and experiment group. Results: The enzyme digestion electrophoresis and sequencing results showed that the gene sequence of the EA. hy926 cells over-expression lentivirus vector in experiment group was completely consistent with the designed and synthesized sequence. The lentivirus titer in control group was 1 X 10 TU • mL , and the lentivirus titer in experiment group was 3X 10 TU • mL . The EA. hy926 cells were successfully infected with the lentivirus under fluorescence microscope and the infection efficiency was above 95%. The qPCR detection results showed that the expression level of RHBDF2 mRNA in the EA. hy926 cells in experiment group was higher than that in control group (P'<0.01). The Western blotting results showed that the expression level of RHBDF2 protein in the EA. hy926 cells in experiment group was higher than that in control group ( P < 0. 05 ). Conclusion: The lentivirus vector over-expressing RHBDF2 is successfully constructed∗ and the EA. hy926 cell line stably up-regulating the expression of RHBDF2 is established by using pLV [Exp]-EGFP-RHBDF2 lentivirus.

SDF-1α promotes repair of myocardial ischemic necrosis zones in rats.

OBJECTIVE: To explore the repair effect of stromal cell-derived factor-1α (SDF-1α) on myocardial ischemic necrosis zones. METHODS: Lentivirus (LV-SDF-1α-GFP) containing SDF-1α target gene was established, the separated and cultured neonatal rat cardiac fibroblasts were transfected, and caudal intravenous injection of isoproterenol was conducted to prepare a rat model of myocardial ischemia. Small animal ultrasound was used to evaluate the effect on cardiac functions. Morphology and immunofluorescence were used to observe the change of ischemic necrosis zones and expressions of stem cellular markers c-kit, CD34, nkx2.5, and nanog, and a quantitative analysis was performed. RESULTS: The established LV-SDF-1α-GFP was used to transfect myocardial fibroblasts which presented GFP green fluorescent expression and could secrete SDF-1α. The small animal ultrasound system showed that rat cardiac functions of the lentivirus group and cell group were improved to different degrees, myocardial ischemic necrosis zones of lentivirus group and cell group were reduced, and differences had statistical significances (P<0.05). Immunofluorescence showed that expressions of stem cellular markers c-kit, CD34, nkx2.5 and nanog in myocardial tissue ischemic zones in both the lentivirus group and cell group increased, and differences through inter-group comparison had statistical significances (P<0.05). CONCLUSION: SDF-1α can promote migration and proliferation of stem cells into the myocardial ischemic necrosis zone, participate in repair of the myocardial necrosis zone, and improve cardiac function.

Construction of lentivirus-mediated mito-OGG1 gene overexpression and OGG1 gene knockdown model in 661W cells / 中华实验眼科杂志

Objective To construct and authenticate the lentiviral-mediated overexpression of mouse mitochondrial-targeted-8-oxoguanine DNA-glycosylase 1 (mito-OGG1) gene and the lentiviral-mediated short hairpin RNA (shRNA) down-regulation of OGG1 gene expression model in 661W cells.Methods Constructed the target plasmids,including pLenti-EF1a-EGFP-P2A-Puro-CMV-Mito-OGG1-3Flag (pLenti-OGG1-GFP) and pLKD-CMV-G&PR-U6-shRNA (pLKD-shRNA).293T cells were used to obtain green fluorescent protein (GFP)-tagged lentiviral vector of interest by using a second generation lentivirus packaging system.293T cells were also used for the virus titer estimation.The multiplicity of infection (MOI) of 661W cells was detected by fluorescence microscopy.A stable transfected cell line was screened by puromycin.Immunofluorescence was used to detect transfection efficiency and cytochrome C oxidase Ⅳ (COXⅣ)-OGG1 co-localization.OGG1 mRNA and protein expression levels were detected by real-time qantitative PCR (QPCR) and Western blot.Results Sequencing results showed that the inserted sequence in the over-expression plasmid was consistent with the mouse OGG1 (NM_010957.4) gene sequence in the gene library.The original lentiviral titer after packaging and purification was between 2.0× 107to 6.0× 107 TU/ml.The optimal MOI of 661W cells was 40,and puromycin with a concentration of 4.0 μg/ml successfully screened stable transformation.The transfection efficiency was up to 100％ after screening.Immunofluorescence demonstrated successful co-localization of OGG1 and COXⅣ.The relative expression levels of OGG1 mRNA in the blank control group,OGG1 group,overexpression control group,shRNA group and low expression control group were 1.000±0.000,41.581±12.206,0.888±0.056,0.239±0.121 and 1.081±0.083,and the relative expression levels of OGG1 protein were 1.029±0.153,1.657 ± 0.237,0.752 ± 0.143,0.471 ± 0.149 and 1.036 ± 0.185,respectively,with significant differences between them (F=44.654,30.948;both at P＜0.05),the relative expression levels of OGG1 mRNA and protein in the OGG1 group were significantly higher than those in the overexpression control group,the relative expression levels of OGG1 mRNA and protein in the shRNA group were significantly lower than those in the lower expression control group,with significant differences between them (all at P＜0.05).Conclusions The mitoOGG1 overexpression and OGG1 knockdown models of 661W cells are successfully constructed,which provides the preliminary experimental basis for follow-up study.

Effects of silencing the HIF-1α gene on the expression of BSP and osterix in rat BMMSCs under tension / 口腔疾病防治

Objective@#To explore the effect of hypoxia inducible factor 1α (HIF-1α) gene silencing in rat bone marrow mesenchymal stem cells (BMMSCs) under mechanical distraction on the expression of bone sialoprotein (BSP) and osterix and to provide a new idea for repairing bone defects with BMMSCs.@*Methods @#The shRNA sequence was designed according to the rat HIF-1α gene, and the pGMLV-SC1RNAi lentiviral vector was cloned after PCR amplification. After screening positive clones and identifying competent transformed cells by sequencing, 293T cells were packaged and titered, rat BMMSCs were transfected and cultured in vitro. Clones with stably silenced HIF-1α expression were screened by inverted fluorescence microscopy. The RNAi response experiment was divided into four groups: the blank control group, the HIF-1α shRNA group, the negative control group, and the response group. Western blot was used to detect the expression of HIF-1α protein in the four groups to verify the response of the target genes and exclude off-target effects. A Flexcell FX-5000T cell stress loading system was used to intervene in the mechanical stretch of the cells. qRT-PCR and Western blot were used to detect the expression of BSP and osterix in the blank control group, HIF-1α shRNA group, and negative control group.@*Results@#The HIF-1α shRNA lentiviral vector was successfully constructed. The results of the RNAi response showed no significant difference in the expression of HIF-1α between the response and the blank control group (P > 0.05). The recombinant lentivirus could effectively silence HIF-1α in BMMSCs. After mechanical distraction of the BMMSCs, compared with the blank and negative control groups, the HIF-1α shRNA group showed significantly increased mRNA and protein expression of the bone-related factors BSP and osterix (P < 0.05); there was no significant difference in the mRNA and protein expression of BSP or osterix between the blank and negative control groups (P > 0.05).@*Conclusion @#Silencing HIF-1α in BMMSCs under mechanical distraction can promote the expression of BSP and osterix.

Preparation of DJ-1 overexpressing cell model by using lentiviral vector / 基础医学与临床

Objective To prepare gene overexpressing cell model of human wild-type DJ-1 and its L166P mutant, and to investigate the role of lentiviral vector in gene overexpressing cell model .Methods Wild type DJ-1 and L166P mutant DJ-1 lentiviral vector plasmids were respectively constructed .After sequencing and comparing cor-rectly, the plasmid was amplified and transfected into HEK 293T cell line.Expression of WT DJ-1 and L166P mu-tant DJ-1 in cell lines was detected by fluorescence and Western blot .After determining the accurate expression of the target protein, a large amount of HEK293T cells was transfected and packaged to produce lentiviral particles. The PC12 cells were infected with the titer of virus supernatant.The fluorescence intensity of GFP and the expres-sion of target protein were observed by fluorescence microscope and Western blot method ,and the infection effi-ciency of the virus was determined .Results Lentiviral vectors carrying wild type DJ-1 and its mutants were suc-cessfully constructed .The virus vector can be transfected into HEK 293T cells and the target protein can be correctly expressed.The viral titers of LV-DJ-1 and LV-DJ-1/L166P were 2×109 TU/mL and 2×108 TU/mL, respectively. Virus supernatant can efficiently infect PC 12 cells, and most cells can express target proteins .The protein expres-sions of exogenous wild-type DJ-1 and L166P mutants were 315% and 285% of endogenous content ,respectively. Conclusions Lentivirus vector can infect cells efficiently , and it is a good way to prepare gene over expressing cell model.A cell model overexpressing DJ-1 or its L166P mutant is successfully prepared .The model can be used for subsequent DJ-1 function research .

Transfection with lentivirus carrying Ifi204 genes up-regulates p204 expression of the aortic vascular fibroblasts in rats / 基础医学与临床

Objective To observe the effect of transfection with lentivirus carrying Ifi204 genes on the expression of p204 in rat vascular adventitial fibroblasts. Methods Culturing the vascular adventitial fibroblasts of rat aortic and then conducting immunocytochemistry to identify the type and purity of these rat fibroblasts. The vascular adventitial fibroblasts of rat aortic cultured were transfected with lentivirus vector system carrying Ifi204 genes (Ifi204 group), the fibroblasts which has been transfected with the empty vector lentivirus particles as the control group (group C), and the untreated fibroblasts as the blank group (group N). The expressions of mRNA and protein of p204 in the fibroblasts were detected by realtime fluorescent quantitative PCR and Western blot test separately. Results There was expression of p204 in group N. Compared with group N and group C, mRNA and protein expression of p204 in the Ifi204 group had been all upregulated (P＜0.01). Conclusions There is structural expression of p204 in vascular adventitial fibroblasts of rat aortic. Transfection with lentivirus carrying Ifi204 genes can upregulate the expression of p204 in vascular adventitial fibroblasts.

Construction and expression of a lentivirus expression vector carrying the VEGF165-EGFP fusion gene in breast cancer MCF-7 cells.

Vascular endothelial growth factor (VEGF)165 is one of the most abundant and potent angiogenic factors in both physiological and pathological conditions. However, the function and mechanism of VEGF165 in tumors and their environment remain to be elucidated. In the present study, a lentivirus vector (LV) that contained the VEGF165-enhanced green fluorescent protein (EGFP) fusion gene was constructed and transfected into the human breast cancer cell line MCF-7. Following transfection, the expression of VEGF165 in MCF-7 cells was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. Further cellular localization of VEGF165 was observed through fluorescence microscopy. The titer of the recombinant lentivirus was 5.44×107 TU/ml in the LV-VEGF165-EGFP group and 5.00×108 TU/ml in the LV-EGFP negative control group. RT-qPCR and western blotting demonstrated that the expression of VEGF165 was significantly increased in the LV-VEGF165-EGFP group compared with the control group. The present study lays the foundation for in vitro and in vivo studies on tumor cell derived-VEGF165. Furthermore, the present fusion gene expression vector may provide a potential approach for gene therapy treatment of cancer and other diseases that require regulation of angiogenesis.

Cotransfecting norepinephrine transporter and vesicular monoamine transporter 2 genes for increased retention of metaiodobenzylguanidine labeled with iodine 131 in malignant hepatocarcinoma cells.

Norepinephrine transporter (NET) transfection leads to significant uptake of iodine-131-labeled metaiodobenzylguanidine (131I-MIBG) in non-neuroendocrine tumors. However, the use of 131I-MIBG is limited by its short retention time in target cells. To prolong the retention of 131I-MIBG in target cells, we infected hepatocarcinoma (HepG2) cells with Lentivirus-encoding human NET and vesicular monoamine transporter 2 (VMAT2) genes to obtain NET-expressing, NET-VMAT2-coexpressing, and negative-control cell lines. We evaluated the uptake and efflux of 131I-MIBG both in vitro and in vivo in mice bearing transfected tumors. NET-expressing and NET-VMAT2-coexpressing cells respectively showed 2.24 and 2.22 times higher 131I-MIBG uptake than controls. Two hours after removal of 131I-MIBG-containing medium, 25.4% efflux was observed in NET-VMAT2-coexpressing cells and 38.6% in NET-expressing cells. In vivo experiments were performed in nude mice bearing transfected tumors; results revealed that NET-VMAT2-coexpressing tumors had longer 131I-MIBG retention time than NET-expressing tumors. Meanwhile, NET-VMAT2-coexpressing and NET-expressing tumors displayed 0.54% and 0.19%, respectively, of the injected dose per gram of tissue 24 h after 131I-MIBG administration. Cotransfection of HepG2 cells with NET and VMAT2 resulted in increased 131I-MIBG uptake and retention. However, the degree of increase was insufficient to be therapeutically effective in target cells.

In vitro reprogramming of rat bmMSCs into pancreatic endocrine-like cells.

Islet transplantation provides curative treatments to patients with type 1 diabetes, but donor shortage restricts the broad use of this therapy. Thus, generation of alternative transplantable cell sources is intensively investigated worldwide. We previously showed that bone marrow-derived mesenchymal stem cells (bmMSCs) can be reprogrammed to pancreatic-like cells through simultaneously forced suppression of Rest/Nrsf (repressor element-1 silencing transcription factor/neuronal restrictive silencing factor) and Shh (sonic hedgehog) and activation of Pdx1 (pancreas and duodenal transcription factor 1). We here aimed to reprogram bmMSCs further along the developmental pathway towards the islet lineages by improving our previous strategy and by overexpression of Ngn3 (neurogenin 3) and NeuroD1 (neurogenic differentiation 1), critical regulators of the development of endocrine pancreas. We showed that compared to the previous protocol, the overexpression of only Pdx1 and Ngn3 reprogrammed bmMSCs into cells with more characteristics of islet endocrine lineages verified with bioinformatic analyses of our RNA-Seq datasets. These analyses indicated 2325 differentially expressed genes including those involved in the pancreas and islet development. We validated with qRT-PCR analysis selective genes identified from the RNA-Seq datasets. Thus, we reprogrammed bmMSCs into islet endocrine-like cells and advanced the endeavor to generate surrogate functional insulin-secreting cells.