Many diseases are potential targets for gene therapy using either non-viral or viral vectors. Unlike nonviralmethods, viral vectors, such as lentiviruses, have the ability to integrate into the host chromosome,which can lead to long-term transgene expression. Lentiviruses have advantages over other types ofviruses due to their capacity to transduce non-dividing cells. An optimized generation of lentivirusescarrying green fluorescent protein (GFP) reporter gene driven by either UbC (LV/UbC/GFP) orCMV (LV/CMV/GFP) promoter is described in this paper. The lentiviruses were produced by cotransfectinglentiviral expression constructs and packaging mix into 293FT lentivirus producer cell lines.Lipofectamine was highly efficient in transfecting the cells compared to Transfast and Polyethyleneimine(PEI). Following cell transfection, syncytia were clearly visible at day 2. Lentiviruses were harvestedat days 1, 2 and 3 post-transfection. The highest transduction efficiency was read from LV/CMV/GFPharvested at day 2 post-transfection and LV/UbC/GFP harvested at day 3 post-transfection. Finally,the GFP expression in COS-7 cells was determined at day 2 and day 14 post-transduction for transientand stable GFP expression. It was found that the GFP expression declined overtime. However, thetransduction efficiency and duration of the transgene expression in COS-7 cells transduced with LV/CMV/GFP were higher compared to LV/UbC/GFP. In conclusion, we have successfully produced lentivirusescarrying GFP with different promoters and shown that the viruses were able to infect COS-7 cells atdifferent efficiencies. Meanwhile, the generation of the active lentiviruses will allow us to proceed to the subsequent analysis of the effect of regulatory elements in future study.
iPS cells were originally generated using monocistronic retroviral vectors carrying the Yamanaka factors ‘OSKM’. The development of a polycistronic viral vector with OSKM linked by 2A peptides has simplified reprogramming procedure and reduced the risk of multiple proviral integrations and insertional mutagenesis. In this study, we demonstrated the production of the polycistronic lentiviral vector encoding OSKM in a single cassette without a reporter gene or drug-based selection system. Syncytia formations were clearly seen following the co-transfection of a lentiviral plasmid construct with the structural and packaging plasmids. The virion was collected at 48 hours post-transfection. Afterwards, the viral titers were measured by the expression of Sox2 protein from transduced HT1080 cells. Subsequently, Oct4 expression was successfully detected in mouse fibroblasts in the range of 5, 10 and 20 MOIs with expression of 90.7%, 97.5% and 98%, respectively. The results obtained from this study could be used as a model for the production of OSKM lentiviral vector for newcomers to cellular reprogramming research.
Introduction: MiR-3099 was reported to play a role in neuronal cell differentiation/function in the brain during late embryonic and early neonatal development. To further explore its potential regulatory effects on embryonic brain development, this study aims to construct and validate an expression vector of miR-3099 for future gain-of-function and loss-of-function studies. Methods: pCAG-eGFP vector was modified to include IRES2 and miR-3099 with 150bp upstream and downstream genomic sequences. The newly constructed vector, pCAG-miR-3099-IRES2-eGFP, consists of CAG promoter. The in vitro expression level of miR-3099 was measured using stem-loop RT-qPCR after it was transfected into 293FT cell. Later, the vector was electroporated into the embryonic brain at E15.5. Three days later, the E18.5 embryonic brain was harvested and cryopreserved. Immunohistochemistry was performed by using antibody against eGFP to validate the in utero expression of the transgene in the neocortex of the brain. Results: Our finding showed that, the expression level of miR-3099 was significantly upregulated (p
Breast cancer is one of the most common malignancies among woman. Decades of scientific study have linked the
overexpression of ERBB2 antigen to aggressive tumors. To target aggressive breast cancer, chimeric antigen receptor
(CAR) technology can be utilized. For this, human T-cells are transduced with a gene sequence encoding a CAR that is
specific for tumor-associated antigens (TAAs). These genetically-engineered CAR transduced T-cells (CAR-T cells) are
able to target the tumor antigen without the need for major histocompatibility complex (MHC) recognition, rendering
it a potentially universal immunotherapeutic option. However, efficient transduction of therapeutic gene into human
T-cells and further cell expansion are challenging. In this study, we reported a successful optimization of a transduction
protocol using spinoculation on CD3+ T-cells with different concentrations of lentiviral plasmid encoding the CAR gene.
CD3+T-cells were isolated from the peripheral blood mononuclear cells (PBMCs). The constructed CAR gene was inserted
into a lentiviral plasmid containing the green fluorescent protein (GFP) tag and lentiviral particles were produced. These
lentiviral particles were used to transduce activated T-cells by spinoculation. T-cells were activated using Dynabeadconjugated
CD3/CD28 human T-cell activator and interleukin-2 (IL-2) before transduction. CD3+ T-cells were selected
and GFP expression, which indicated transduction, was observed. Future studies will focus on in vitro and in vivo models
to determine the efficiency of CAR-T cells in specifically targeting ERBB2-expressing cells.