Pigs are considered as ideal donors for xenotransplantation because they have many physiological and anatomical characteristics similar to human beings. However, antibody-mediated immunity, which includes both natural and induced antibody responses, is a major challenge for the success of pig-to-primate xenotransplantation. Various genetic modification methods help to tailor pigs to be appropriate donors for xenotransplantation. In this study, we applied transcription activator-like effector nuclease (TALEN) to knock out the porcine α-1, 3-galactosyltransferase gene GGTA1, which encodes Gal epitopes that induce hyperacute immune rejection in pig-to-human xenotransplantation. Meanwhile, human leukocyte antigen-G5 gene HLA-G5, which acts as an immunosuppressive factor, was co-transfected with TALEN into porcine fetal fibroblasts. The cell colonies of GGTA1 biallelic knockout with positive transgene for HLA-G5 were chosen as nuclear donors to generate genetic modified piglets through a single round of somatic cell nuclear transfer. As a result, we successfully obtained 20 modified piglets that were positive for GGTA1 knockout (GTKO) and half of them expressed the HLA-G5 protein. Gal epitopes on the cell membrane of GTKO/HLA-G5 piglets were completely absent. Western blotting and immunofluorescence showed that HLA-G5 was expressed in the modified piglets. Functionally, the fibroblasts from the GTKO/HLA-G5 piglets showed enhanced resistance to complement-mediated lysis ability compared with those from GTKO-only or wild-type pigs. These results indicate that the GTKO/HLA-G5 pigs could be a valuable donor model to facilitate laboratory studies and clinics for xenotransplantation.
Animals ; Animals, Genetically Modified ; Gene Knockout Techniques ; HLA Antigens ; Humans ; Nuclear Transfer Techniques ; Swine ; Transplantation, Heterologous

Animal models, particularly pigs, have come to play an important role in translational biomedical research. There have been many pig models with genetically modifications via somatic cell nuclear transfer (SCNT). However, because most transgenic pigs have been produced by random integration to date, the necessity for more exact gene-mutated models using recombinase based conditional gene expression like mice has been raised. Currently, advanced genome-editing technologies enable us to generate specific gene-deleted and -inserted pig models. In the future, the development of pig models with gene editing technologies could be a valuable resource for biomedical research.
Animals ; Gene Expression ; Gene Transfer Techniques* ; Mice ; Models, Animal ; Recombinases ; Swine

The intracellular trafficking and subcellular distribution of exogenous gene is very important for gene delivery. A successful gene vehicle should overcome various barriers including endosomal membrane barriers to delivery gene to the target organelle. Traditional nonviral vehicle is unable to avoid endosomal pathway efficiently, so the efficiency of gene delivery is low and the application of gene drugs is limited. In order to achieve efficient nonviral gene delivery, a lot of researches based on endosomal escape have been carried out and some agents with the function of endsomal escape have been found. These agents facilitate the endsomal escape via various mechanisms, such as fusion into the lipid bilayer of endosomes, pore formation in the endosomal membrane, proton sponge effect and photochemical methods to rupture the endosomal membrane. In this review, various reported strategies for endsomal escape are described according to the escape mechanisms, and their applications in intracellular gene delivery are also discussed.
Cell Membrane ; metabolism ; Endosomes ; metabolism ; Gene Transfer Techniques ; Genetic Therapy ; Genetic Vectors ; Humans

OBJECTIVETo develop an alternative method for assessment of gene delivery systems in vivo.

METHODSMouse primary spleen lymphocytes were genetically modified in vitro by a retroviral vector harboring a Gaussia luciferase (Gluc) expression cassette. After implantation of these cells into recipient mice, the expression of Gluc was detected in whole blood or plasma collected.

RESULTSAs little as 10 muL whole blood drawn from the recipient mice could guarantee prompt reading of Gluc activity with a luminometer. And the reading was found in good correlation with the number of genetically modified spleen lymphocytes implanted to the mice.

CONCLUSIONSGluc may be useful as an in vivo reporter for gene therapy researches, and Gluc blood assay could provide an alternative method for assessment of gene delivery systems in vivo.

Animals ; Arecaceae ; enzymology ; Cell Line ; Gene Transfer Techniques ; Genes, Reporter ; Humans ; Luciferases ; genetics ; Mice

The study of viruses traditionally focused on their roles as infectious agents and as tools for understanding cell biology. Recently, however, with the development of structural biology, viruses have now been receiving particular attention in nanotechnology. By chemical methods or by gene modification, viruses have been functionalized as potential building blocks for several applications, such as drug/gene delivery vehicles, advanced vaccine vehicles, and special inorganic or organic nanomaterials. Here we highlight some of the recent progresses in the medical applications of viruses.
Biomedical Research ; trends ; Gene Transfer Techniques ; Genetic Therapy ; Nanostructures ; Nanotechnology ; trends ; Vaccines ; Viruses

Animals ; Dependovirus ; genetics ; immunology ; Gene Transfer Techniques ; instrumentation ; Genetic Therapy ; instrumentation ; Genetic Vectors ; genetics ; immunology ; Humans

The efficacy of recombinant adeno-associated virus (rAAV) vector-mediated gene delivery to the gastrointestinal tract has been paid a considerable attention over the last 10 years, since our first report on the oral gene pill strategy in Nature Medicine, even though there are still several potential obstacles for this route to overcome in order to obtain efficient gene delivery. The preclinical results of oral rAAV gene medicine are summarized in this review, and special attention is paid on its pharmacokinetic and pharmacodynamic aspects with an emphasis on drug delivery, absorption, distribution and transduction. The rAAV based vectors have been shown promising results in human clinical trials with fewer safety concerns over other gene medicines. However, the underlying mechanisms and biopharmaceutical features of oral rAAV gene medicine remain to be explored extensively and intensively to develop this novel technology as a treatment for a wider range of diseases.
Administration, Oral ; Dependovirus ; genetics ; Drug Carriers ; Gene Transfer Techniques ; Genetic Therapy ; methods ; Genetic Vectors ; Humans

In vitro gene delivery, polyethyleneimine (PEI) has been described as one of the most efficient nonviral vector. Herein the formation mechanism of PEI/DNA complexes is elucidated. The transition phase of "bead-on-string" structure in the formation of complexes was supposed to exist through spectroscopy, electrophoresis and transmission electron microscopy (TEM) technology. The construction of PEI/DNA complexes is related closely to the characteristics of PEI and DNA plasmid. As well as the dominant electrostatic effects, the nonelectrostatic interactions were thought to be partially responsible for the presence of PEI/DNA complexes even in the high ionic strength. The surface charge of complexes particles increased with the N/P ratio, but the absolute value of zeta potential was lower at the N/P ratio of 8 and 12, perhaps attributed to the use of larger DNA plasmid. As a result, the repulsion between particles was decreased and prone to aggregate to the structure like a clustered grape-string in the solution. Interestingly, contrast to the formation behavior of complexes, the PEI/DNA complexes aggregated primarily due to hydrophobic interactions while electrostatic attractions play a little role in the complexes particles aggregation in different concentrations of salt solutions. Comparable transfection efficiency in HepG2 cells was observed for the Lipofectamine 2000 and PEI/DNA complexes at the N/P ratio of 12, and showed that larger or aggregable complexes could transfect the cells in some different mechanisms.
DNA ; genetics ; Drug Carriers ; Gene Transfer Techniques ; Genetic Therapy ; Polyethyleneimine ; chemistry ; Transfection

Drug development and preclinical trials are challenging processes and more than 80% to 90% of drug candidates fail to gain approval from the United States Food and Drug Administration. Predictive and efficient tools are required to discover high quality targets and increase the probability of success in the process of new drug development. One such solution to the challenges faced in the development of new drugs and combination therapies is the use of low-cost and experimentally manageable in vivo animal models. Since the 1980's, scientists have been able to genetically modify the mouse genome by removing or replacing a specific gene, which has improved the identification and validation of target genes of interest. Now genetically engineered mouse models (GEMMs) are widely used and have proved to be a powerful tool in drug discovery processes. This review particularly covers recent fascinating technologies for drug discovery and preclinical trials, targeted transgenesis and RNAi mouse, including application and combination of inducible system. Improvements in technologies and the development of new GEMMs are expected to guide future applications of these models to drug discovery and preclinical trials.
Animals ; Drug Discovery ; Gene Transfer Techniques ; Genome ; Mice* ; Models, Animal ; United States Food and Drug Administration

OBJECTIVESTo investigate the effect of ionizing radiation on liposome-mediated gene delivery and find out a way to improve gene transfection.

METHODSPrior to liposome transfection, HR-8348 cells were irradiated at doses of 0, 2, 4, 8 Gy selected according to the surviving fraction line of HR-8348 cells after different dosage of radiation. After 36 h of liposome transfection, green fluorocytes were counted. The transfection efficiency was figured out and compared with each other.

RESULTSThe transfection efficiency of liposome-mediated gene delivery was 21.32%, 62.17%, 68.00%, 77.78% at the dose of 0, 2, 4, 8 Gy respectively and the clinical dose (2 Gy) was as high as 62.17%. Combined radiation and liposome-mediated gene delivery achieved the approximate transfection efficiency of virus vector.

CONCLUSIONIonizing radiation can improve the transfection efficiency of liposome-mediated gene delivery markedly and it is expected to treat human malignancy with liposome-mediated gene delivery combined with radiation.

Dose-Response Relationship, Radiation ; Gene Transfer Techniques ; Genetic Therapy ; Humans ; Liposomes ; Rectal Neoplasms ; therapy ; Transfection