Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In contrast to oncoviruses, lentiviruses do not require target cell division for integration into the host genome. Lentiviral vectors can therefore expand the spectrum of target cells susceptible to retroviral gene transfer. To analyze whether vectors based on simian immunodeficiency viruses (SIVs) could be used for gene transfer, a three-plasmid vector-packaging system was developed, in which Gag-Pol and the vector itself are of SIV origin, while Env is derived either from SIV, amphotropic murine leukemia virus (MuLV), or the G glycoprotein of vesicular stomatitis virus (VSV-G). To increase the safety of the SIV vector system, a self-inactivating SIV vector was constructed. After optimization of the SIV gag-pol expression plasmid, a minimal SIV vector, which contained only SIV sequences present on the multiply spliced nef transcript, could still be produced at titers of 2 x 10(5) infectious units/ml. Growth-arrested cells could be transduced with this vector even if vif, vpr, vpx, and nef had been deleted from the packaging construct and the vector.
 ...
PMID:Development of a self-inactivating, minimal lentivirus vector based on simian immunodeficiency virus. 1069 18

In the absence of viral envelope gene expression, cells expressing human immunodeficiency virus type 1 (HIV-1) gag and pol, accessory HIV functions, and a vector genome RNA produce and secrete large amount of noninfectious virus-like particles (VLPs) into the conditioned medium. After partial purification, such HIV-1 VLPs can be made infectious in cell-free conditions in vitro by complex formation with lipofection reagents or with the G protein of vesicular stomatitis virus (VSV-G). The resulting in vitro-modified HIV-1 particles are able to infect nondividing cells. Infectivity of envelope-free HIV VLPs can also be induced by prior modification of target cells through exposure to partially purified VSV-G vesicles. Similarly, infection can be carried out by attachment of envelope-free noninfectious VLPs to unmodified cells followed by subsequent treatment of cells with VSV-G. We interpret these findings to indicate that interaction between a viral envelope and a cell surface receptor is not necessary for the initial virus binding to the cells but is required for subsequent cell entry and infection.
 ...
PMID:Separable mechanisms of attachment and cell uptake during retrovirus infection. 1104 24

Jembrana disease virus (JDV) is a newly isolated and characterised bovine lentivirus. It causes an acute disease in Bali cattle (Bos javanicus), which can be readily transmitted to susceptible cattle with 17% mortality. There is as yet no treatment or preventive vaccine. We have developed a gene transfer vector system based on JDV that has three components. The first of the components is a bicistronic transfer vector plasmid that was constructed to contain cis-sequences from the JDV genome, including 5'- and 3'-long terminal repeats (LTRs), 0.4kb of truncated gag and 1.1kb of 3'-env, a multiple cloning site to accommodate the gene(s) of interest for transfer, and an internal ribosome entry site plus the neomycin phosphotransferase (Neo) gene cassette for antibiotic selection. The second element is a packaging plasmid that contains trans-sequences, including gag, pol, vif, tat and rev, but without the env and packaging signals. The third is a plasmid encoding the G glycoprotein of vesicular stomatitis virus (VSV-G) to supply the vector an envelope for pseudotyping. Cotransfection of 293T cells with these three plasmid components produced VSV-G pseudotyped, disabled, replication defective, bicistronic JDV vectors encoding the green fluorescent protein (EGFP) and the Neo resistance selection maker simultaneously with a titre range of (0.4-1.2)x10(6)CFU/ml. Transduction of several replicating primary and transformed cells from cattle, primate and human sources and importantly growth-arrested cells with the JDV vectors showed high efficiency of EGFP gene transfer at 35-75%, which was stable and the expression of EGFP was long term. Furthermore, these JDV vectors were designed to suit the inclusion and expression of genes corresponding to JDV specific proteins, such as gag or env, for the development of vaccines for Jembrana disease. This strategy should also be applicable to other bovine diseases as well. The design and construction of the JDV vector system should facilitate the study of the lentivirology and pathogenesis of the diseases associated with JDV or other bovine virus infections. To our knowledge, this is the first such vector system developed from a cattle virus.
 ...
PMID:Development of disabled, replication-defective gene transfer vectors from the Jembrana disease virus, a new infectious agent of cattle. 1127 19

We have successfully generated and characterized a stable packaging cell line for HIV-1-based vectors. To allow safe production of vector, a minimal packaging construct carrying only the coding sequences of the HIV-1 gag-pol, tat, and rev genes was stably introduced into 293G cells under the control of a Tet(o) minimal promoter. 293G cells express the chimeric Tet(R)/VP16 trans-activator and contain a tetracycline-regulated vesicular stomatitis virus protein G (VSV-G) envelope gene. When the cells were grown in the presence of tetracycline the expression of both HIV-1-derived and VSV-derived packaging functions was suppressed. On induction, approximately 50 ng/ml/24 hr of Gag p24 equivalent of vector was obtained. After introduction of the transfer vector by serial infection, vector could be collected for several days with a transduction efficiency similar or superior to that of vector produced by transient transfection both for dividing and growth-arrested cells. The vector could be effectively concentrated to titers reaching 10(9) transducing units/ml and allowed for efficient delivery and stable expression of a GFP transgene in the mouse brain. The packaging cell line and all vector producer clones described here were shown to be free from replication-competent recombinants, and from recombinants between packaging and vector constructs that transfer the viral gag-pol genes. The packaging cell line and the assays developed will advance lentiviral vectors toward the stringent requirements of clinical applications.
 ...
PMID:A new-generation stable inducible packaging cell line for lentiviral vectors. 1138 62

We have previously shown that vesicles containing the spike glycoprotein of the vesicular stomatitis virus (VSV-G) can associate efficiently with immature, non-infectious, envelope-deficient retrovirus-like particles assembled by packaging cells to produce infectious, pseudotyped viruses in cell-free conditions in vitro. We have also previously reported that VSV-G can enhance DNA lipofection efficiency by interacting with liposomes to form fusogenic, serum-stable liposomes with enhanced transfection properties. Here, we report that VSV-G can form a complex directly with naked plasmid DNA in the absence of a lipofection reagent and can thereby enhance the transfection efficiency of the naked plasmid vector. Sucrose gradient sedimentation analysis demonstrated that VSV-G can also associate with plasmid DNA and murine leukemia virus (MLV) gag-pol particles to form ternary complexes that co-sediment with high DNA transfecting activity. The increased transfection efficiency with VSV-G was dependent on the presence of the polycation (Polybrene) in the culture medium during transfection. Enhanced transfection was abolished by a neutralizing antibody to VSV-G. These results may be useful in the study of retrovirus assembly, in the further design of hybrid DNA-based retrovirus-like vectors, and in the full in vitro, cell-free assembly of infectious virus-like particles from component parts.
 ...
PMID:VSV-G envelope glycoprotein forms complexes with plasmid DNA and MLV retrovirus-like particles in cell-free conditions and enhances DNA transfection. 1154 14

Recombinant vaccinia viruses that express defective retroviral vectors upon a single infection event in normal host cells were constructed. The gag-pol and envelope genes and a retroviral vector unit were inserted as vaccinia virus promoter-controlled transcription units at three separate loci. The triple recombinant virus was used to infect such diverse cell types as monkey and rabbit kidney, human lung, and primary chicken cells, resulting in the production of transduction-competent defective retroviral vectors. Infection of Chinese hamster ovary cells, which are nonpermissive for vaccinia virus replication, also resulted in production of retroviral vectors and secondary permanent transduction of the host cells. Since vaccinia virus supports the expression of cytotoxic proteins, the vesicular stomatitis virus G glycoprotein could be chosen as the envelope allowing a broad host range of transduction. Functionality of particles was monitored by expression of the green fluorescent protein in transduced 3T3 cell clones. This is the first description of a single chimeric virus encoding and releasing functional retroviral vectors, providing proof of principle of the new concept. No replication-competent retrovirus was detectable by sensitive reverse transcriptase assays. Since vaccinia virus has a broad host range, is extremely robust, and can be obtained at high titers and safe nonreplicating vaccinia virus strains are available, the hybrid system may open new perspectives for gene delivery.
 ...
PMID:Generation of transduction-competent retroviral vectors by infection with a single hybrid vaccinia virus. 1276 20

The avian retroviruses reticuloendotheliosis virus strain A (REV-A) and spleen necrosis virus (SNV) are not naturally infectious in human cells. However, REV-A-derived viral vectors efficiently infect human cells when they are pseudotyped with envelope proteins displaying targeting ligands specific for human cell-surface receptors. Here we report that vectors containing the gag region of REV-A and pol of SNV can be pseudotyped with the envelope protein of vesicular stomatitis virus (VSV) and the glycoproteins of different rabies virus (RV) strains. Vectors pseudotyped with the envelope protein of the highly neurotropic RV strain CVS-N2c facilitated cell type-specific gene delivery into mouse and human neurons, but did not infect other human cell types. Moreover, when such vector particles were injected into the brain of newborn mice, only neuronal cells were infected in vivo. Cell-type-specific gene delivery into neurons may present quite specific gene therapy approaches for many degenerative diseases of the brain.
 ...
PMID:Cell-type-specific gene delivery into neuronal cells in vitro and in vivo. 1451 61

The notable glomerular feature of human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) is the collapse of the capillary tuft with marked glomerular epithelial cell hyperplasia. These data suggest a loss of normal podocyte function, which is associated with a loss of the podocyte differentiation markers, Wilm's tumor (WT-1), synaptopodin, podocalyxin, and common acute lymphoblastic leukemia antigen (CALLA). We have previously shown that HIV-1 expression can induce these changes in HIV-1 transgenic mice. To identify which HIV-1 gene product(s) are responsible for the phenotypic changes in podocytes, we created multiple mutated HIV-1 constructs and then pseudotyped them with vesticular stomatitis virus glycoprotein (VSVG) envelope to enhance the tropism of these mutant viruses. In addition to gag/pol, the mutant viruses lacked one of the following, env, nef, rev, vif, vpr, or vpu. In addition, we generated single gene expressing pseudotyped viruses to complement the scanning mutation approach of our viral parental construct. Murine podocytes were then infected with one of the viral constructs either lacking or expressing the various HIV-1 genes. We found that HIV-1 nef was necessary and sufficient for proliferation of podocytes and down-regulation of synaptopodin and CALLA. These data suggest that Nef induces many of the changes we observe in HIV transgenic model and, as a result, this now defines the pathway for exploration of host responses to HIV-1 infection.
 ...
PMID:Critical role for Nef in HIV-1-induced podocyte dedifferentiation. 1453 2

Pantropic retroviral vectors pseudotyped with vesicular stomatitis virus envelope G protein (VSV-G) are typically produced by transient transfection of the VSV-G expression plasmid because constitutive expression of VSV-G is cytotoxic. To produce pantropic vectors, the VSV-G expression plasmid and the vector plasmid are cotransfected into a packaging cell line, such as 293-gag-pol. Typically, the ratio of VSV-G plasmid to the vector plasmid ranges from 0.33 to 1.0. However, it is not clear that this range is optimal for vector production. In this study we have systematically examined the effect of the ratio of VSV-G plasmid (pVSV-G) to vector plasmid on vector production. For this, 293-gag-pol stable packaging cells were cotransfected with pVSV-G and an enhanced green fluorescent protein- (EGFP-) expressing retroviral vector plasmid (pLTR-EGFP) by use of lipofectamine. Vector was collected following transfection and used to transduce three target cell lines, namely, 3T3 fibroblasts, telomerase-immortalized human diploid fibroblasts (HDF), and the human hepatoma cell line HuH7. Transduction efficiency was evaluated for vectors produced at different pVSV-G:pLTR-EGFP ratios such that the total amount of plasmid transfected into 293-gag-pol cells was kept constant. Our results indicate that transduction efficiency is greatest when the pVSV-G:pLTR-EGFP ratio is substantially below 1.0. For 3T3 and HDF cells, the maximum transduction efficiency was obtained when a ratio of pVSV-G:pLTR-EGFP ranging from 0.053 to 0.2 was used for transfection. The relative magnitude of this effect was greater for lower transduction efficiencies in control cultures. For HuH7 cells, the beneficial effects were smaller than those observed when HDF or 3T3 cells were used. The difference in transduction efficiency for vector produced under various pVSV-G:pLTR-EGFP ratios was not due to differences in the proliferation of packaging cells or target cells. Further characterization showed that the amount of vector RNA relative to p30gag decreased as the ratio of pVSV-G:pLTR-EGFP increased. These results indicate that transduction efficiency increases with increasing levels of vector RNA as long as a minimally sufficient level of pantropic envelope protein is expressed.
 ...
PMID:Transduction efficiency of pantropic retroviral vectors is controlled by the envelope plasmid to vector plasmid ratio. 1590 66

Low levels of gene delivery in vivo using replication-defective retroviral vectors have severely limited their application for clinical protocols. To overcome this problem, we describe here a semi-replication-competent retrovirus (s-RCR) in which the gag-pol and envelope (VSV-G, vesicular stomatitis virus G protein) genes were split into two vectors. This system offers potential advantages over both replication-defective vectors, in terms of efficiency of in vivo spread through a tumor, and all-in-one replication-competent vectors in terms of the payload of therapeutic genes that can be carried. We achieved a viral titer of s-RCR viruses approximately 70-fold higher than VSV-G pseudotyped, replication-defective vectors. In addition, s-RCR vectors induced tumor killing by the cytotoxicity of VSV-G during viral spread. Inclusion of the herpes simplex virus thymidine kinase (HSVtk30) gene into vectors significantly improved tumor killing activity followed by ganciclovir (GCV) treatment in vitro under conditions of low-level viral replication. However, at high levels of viral spread, VSV-G-mediated cytotoxicity predominated. Xenografts of human fibrosarcoma HT1080 cells, preinfected by semi-replicative green fluorescent protein vectors (semi-GFP), were completely non-tumorigenic in nude mice. Implantation of cells preinfected by semi-replicative TK30 vectors (semi-TK30) mixed with parental HT1080 cells at a ratio of 1:1 efficiently prevented tumor growth in mice treated by GCV. Direct intratumoral injection of HT1080 tumors growing in nude mice, or B16 murine melanoma in immunocompetent mice, with semi-TK30 viruses significantly prolonged survival. Injection of autologous cells (B16) producing semi-TK30 vector into B16 tumors prolonged survival only in mice treated with GCV but not with phosphate-buffered saline (PBS). In contrast, when xenogeneic cells (293T) producing semi-TK30 vectors were injected into B16 tumors, an optimal survival advantage was obtained in mice treated with PBS rather than GCV. These data indicate that complex interactions exist between direct cytotoxicity of VSV-G and HSVtk expression when placed in the context of additional immune parameters, which combine to determine the efficacy of the therapy. Taken together, our data suggest that s-RCR vectors have some potential advantages for development to deliver genes into tumors for cancer treatment but that a combination of factors will impact on the decision as to whether the s-RCR strategy is worth developing to full clinical trials.
 ...
PMID:VSV-G pseudotyped, MuLV-based, semi-replication-competent retrovirus for cancer treatment. 1672 95


<< Previous 1 2 3 4 Next >>