Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CD8+ cells from HIV-infected individuals inhibit HIV replication in cultured CD4+ cells by a nonlytic, non-MHC-restricted mechanism. The activity appears to be mediated in part by a soluble antiviral factor (CAF) secreted by the CD8+ cells. In an attempt to identify this factor a large panel of recombinant cytokines was examined for their effect on HIV replication in CD4+ cells. In addition to interferon-alpha and -beta, TNF alpha, TGF beta, and IL-8 reduced virus replication in a dose-dependent fashion. In some cases, the effect of the cytokine was also dependent on the HIV infection assay used to measure it. Antibodies against the inhibitory cytokines, as well as antibodies against TNF beta, IFN-alpha, IFN-beta, IL-4, and IL-6 did not inactivate the antiviral effect of CAF. The data suggest that CAF does not have identity with known antiviral cytokines and therefore CAF may be a novel antiviral factor.
 ...
PMID:Effect of cytokines on HIV replication in CD4+ lymphocytes: lack of identity with the CD8+ cell antiviral factor. 790 3

This investigation showed that phagocytosis of virulent Salmonella typhimurium by promonocytic leukemia cell line U1, which contains human immunodeficiency virus type 1 (HIV-1) provirus but produces minimal or no virus, and not by uninfected U937 cell line resulted in expression of a functional P glycoprotein. Anti-tumor necrosis factor-alpha (TNF alpha) monoclonal antibody failed to inhibit S. typhimurium-induced P glycoprotein expression. Furthermore, recombinant TNF alpha had no effect on the induction of P glycoprotein expression in U1 cells. These data demonstrate that phagocytosis of virulent S. typhimurium results in an induction of P glycoprotein in association with HIV-1 infection; however, TNF alpha does not appear to play a significant role. Thus, secondary microbial infection in HIV-1-positive persons may play a role in multidrug resistance against antiviral and other antimicrobial agents by an induction of P glycoprotein.
 ...
PMID:Salmonella typhimurium induces expression of P glycoprotein (multidrug resistance 1 gene product) in a promonocytic cell line chronically infected with human immunodeficiency virus type 1. 790 42

Antioxidant molecules have been suggested to be of therapeutic value in the treatment of HIV-infected patients. To evaluate this possibility, we examined in vitro the effects of two types of antioxidant molecules in terms of inhibition of HIV replication in monocytes, one of the main reservoirs of HIV, and also in terms of modulation of the immune competence as measured by PBMC proliferation. We tested the effects of BHA, a phenolic, lipid-soluble, chain-breaking antioxidant, and NAC, a known glutathione precursor with some direct free-radical scavenging properties as well, on the regulation of HIV-1 expression in latently infected U1 cells and in productively and chronically infected U937 cells. Both antioxidants inhibited TNF- or PMA-induced NF-kappa B activity in U1 cells, as well as the sustained NF-kappa B activity permanently induced by the virus itself in chronically HIV-infected U937 cells. This resulted in only a partial inhibition of TNF- or PMA-induced HIV replication in U1 cells, and no detectable effect on HIV replication in chronically infected U937 cells. This may be the first limitation to potential antiviral effects of antioxidant therapies. Another limitation is that antioxidant concentrations high enough to block NK-kappa B activation were shown to have a suppressive effect on immune functions in vitro, because NAC and BHA blocked IL-2-induced PBMC proliferation. These data warrant prudence in the design of antioxidant-based therapies aimed at suppressing HIV replication.
 ...
PMID:Appraisal of potential therapeutic index of antioxidants on the basis of their in vitro effects on HIV replication in monocytes and interleukin 2-induced lymphocyte proliferation. 791 23

Ribozymes are RNA molecules that cleave other RNA molecules. Thus, ribozymes offer a new way of inhibiting expression of specific genes whose nucleotide sequences are known. Intracellular stability of ribozymes is an important factor for their efficacy. We previously showed that hammerhead ribozyme directed against mRNA of tumour necrosis factor alpha (TNF alpha) slowly acquires resistance to degradation in cultured human cells. In order to explain this resistance, we now report on endogenous cellular protein(s) that bind to TNF alpha-ribozyme (TNF alpha-Rz) in solution to form stable complexes during native gel electrophoresis. Suppression of the effects of ribonucleases in the cytoplasmic extracts allowed approximately 80% of the input ribozyme RNA to be recovered in the form of complexes, indicating that complex formation protected the ribozyme from degradation. Treatment of the ribozyme-protein complexes with proteinase K prior to electrophoresis led to the recovery of full-length ribozyme. Interestingly, ribozyme-protein complexes retained cleavage activity, suggesting that the binding is in reversible equilibrium. Analysis of protein cytoplasmic extracts for binding to sub-fragments of TNF alpha-Rz demonstrated that protein binds to a conformational epitope formed by an interaction between the 5' end of TNF alpha-Rz and its catalytic domain. Competition of the ribozyme-protein binding with a ribozyme construct containing DNA instead of RNA at the 5' end, indicated that the ribose phosphate backbone of the 5' end is required for strong binding. The protein responsible for the formation of the complex with low electrophoretic mobility was found to be specific for the TNF alpha-Rz, since ribozyme for HIV-1 integrase gene (Int-Rz), or for human interleukin-2 (IL2-Rz) did not compete significantly with the TNF alpha-Rz binding. Covalent linkage of the IL2-Rz to the 3' end of TNF alpha-Rz, or to the proposed RNA protein binding site conferred protein binding and enhanced the stability and activity of the chimeric molecules. The RNA epitope identified in this study, through its endogenous protein binding, may serve as an oligonucleotide cassette for enhancing the in vivo stability and activity of other RNA molecules in general. This RNA epitope will also be useful in the study of RNA-protein interactions.
 ...
PMID:Interaction between tumour necrosis factor alpha ribozyme and cellular proteins. Involvement in ribozyme stability and activity. 793 19

Ceramide, an intracellular lipid mediator of tumor necrosis factor alpha (TNF-alpha) action, was studied for its effects on the expression of the proviral human immunodeficiency virus type 1 genome in latently infected myelomonocytic cell lines U-1IIIB and OM-10.1. Ceramide treatment resulted in a 20- to 100-fold enhancement of HIV production in these cells. Ceramide also enhanced the expression of the chloramphenicol acetyltransferase gene directed by a human immunodeficiency virus type 1 long terminal repeat in transfected U-937 cells, indicating that ceramide acts at the level of viral transcription. These observations suggest that the TNF-ceramide signaling system may be involved in the regulation of HIV expression in certain myeloid cell types.
 ...
PMID:Stimulation of human immunodeficiency virus type 1 expression by ceramide. 798 82

During various biological processes as inflammation or septic shock, free radical damages are produced by a direct production of oxygen radicals by phagocytes, but also by a TNF-mediated generation in target cells. Antioxidants have been demonstrated as protective against TNF cytotoxicity. We try to measure directly the free radical produced by murine recombinant TNF on L929 cells, by detecting the direct light produced by decomposition of superoxide using an adapted chemiluminometer. We measure also the chemiluminescence after addition of luminol. These techniques demonstrate the effective production of oxygen radicals. Unfortunately they have a rather poor specificity and sensitivity. So we use the protective effect of antioxidants on cytotoxicity to investigate the origin of the productive mechanism. We evaluate cytotoxicity of 1 U/ml TNF on L929 murine fibroblasts after 24 hours incubation with actinomycin D by the MTT and Cr51 release. Using the MTT test we observe that addition of thiourea or catalase has the better protecting effect when Zu-Zn SOD had few effect. Reversely using the Cr51 release we observe a good protective effect of Cu-Zn SOD simultaneously with a good protective effect of catalase. So the difference in the effect of various antioxidant agent do not permit to identify the species generated, but depend more on the ability of the antioxidant to reach the cell compartment tested by the method (membrane, or mitochondria). The oxidative effect of TNF is beneficial in physiological condition to destroy cancerous or virus infested cells infested by virus inside the body. But this effect can be deleterious in situation of deficiency in some antioxidant. TNF-induced free radicals can increase the replication of virus as HIV-1 and destroy immunocompetent cells as T cells. This last action explains the defect in cellular immunity observed in oxidative stress and the immunostimulatory effect of many antioxidants.
 ...
PMID:[Tumor necrosis factor (TNF) and oxygen free radicals: potential effects for immunity]. 801 9

Tumor necrosis factor alpha (TNF-alpha) and 12-0-tetradecanoyl phorbol-13-acetate (TPA) activate human immunodeficiency virus type 1 (HIV-1) in U1 cells that are latently infected with HIV-1 to produce viral particles. Pertussis toxin, which inactivates several members of the G protein family of signaling components, including Gi, Go, and transducin, was found to inhibit either TPA or TNF-alpha induction of HIV-1 in U1 cells at the concentration of 1-10 ng/ml. Chloramphenicol acetyl transferase (CAT) assay revealed that pertussis toxin could inhibit HIV-1 gene expression. B-oligomer, the mitogenic and non-ADP-ribosylating component of pertussis toxin, did not show any effect on HIV-1 replication alone or in combination with TNF in the same concentration range. It was of particular interest to note that a single protein (Gi) with a molecular weight of 40 kDa was dose-dependently ADP-ribosylated after treatment with pertussis toxin in U1 cells. The degree of ADP ribosylation of Gi corresponded well to that of inhibition of HIV-1 upon treatment with pertussis toxin. These results strongly support the contention that TPA and TNF-alpha induction of HIV-1 is mediated by a Gi-like receptor-effector coupling protein in the membrane of U1 cells. On the basis of these findings, we propose a model for signal transduction of HIV-1 expression through c-kinase-dependent (TPA) and c-kinase-independent (TNF-alpha) pathways in the U1 cell to determine the point at which Gi-like protein is involved.
 ...
PMID:Pertussis toxin inhibits induction of human immunodeficiency virus type 1 in infected monocytes. 805 61

In human astrocytoma and neuroblastoma cell lines tumour necrosis factor alpha (TNF alpha) and interleukin 1 beta (IL-1 beta) induced NFKB and an additional KB-specific protein of approximately 80 K to bind the HIV-1 enhancer. One nucleoprotein complex contained prototypical NFKB comprising of p50 and p65 subunits and a second contained the p65 subunit and an 80 K factor, p80. Over a 24 hr period of cytokine stimulation the p50/p65 complex of NFKB was present in the nucleus whilst the second complex declined in abundance after two hours due to the decline of p80. In unstimulated cells, DNAse I footprinting revealed a previously unidentified octamer-like binding site in the negative regulatory element (NRE) of the HIV-1 long terminal repeat (LTR) which specifically bound protein factors present in human astrocytoma, neuroblastoma and murine oligodendroglioma cell lines. A second unique motif, also in the NRE, was observed with extracts from one human neuroblastoma cell line and a murine oligodendroglioma. Footprinting analysis also confirmed that Sp1, TATA, Site A and Site B motifs of the LTR were occupied by nuclear factors present in neural cells.
 ...
PMID:Tumour necrosis factor alpha and interleukin-1 beta induce specific subunits of NFKB to bind the HIV-1 enhancer: characterisation of transcription factors controlling human immunodeficiency virus type 1 gene expression in neural cells. 807 13

We have previously shown that the Tat protein of human immunodeficiency virus type 1 (HIV-1) transactivates tumor necrosis factor alpha and beta (TNF alpha and TNF beta) gene expression in HIV-1-infected and in tat-transfected T-lymphocytic and monocytic cell lines. The product encoded by the first exon of the tat gene (amino acids 1 to 72) is sufficient for this transactivation. Here we show that (i) the NF-kappa B and Sp1 binding sites of the TNF beta promoter are required for Tat-mediated transactivation and (ii) a predicted stem-loop structure in the TNF beta mRNA leader region, which resembles the Tat-responsive element of the HIV-1 long terminal repeat (TAR) and which is therefore termed TAR-like, is essential for TNF beta transactivation by Tat. These data suggest that similar promoter regulatory elements are necessary for Tat-mediated transactivation of both TNF beta and HIV-1 gene expression. This represents the first demonstration of a cellular gene with a regulatory element downstream of the transcriptional initiation site that, like TAR, may function as an RNA element.
 ...
PMID:The human immunodeficiency virus type 1 Tat protein transactivates tumor necrosis factor beta gene expression through a TAR-like structure. 813 45

Plasma levels of tumor necrosis factor-alpha (TNF alpha) and the ability of plasmas to induce HIV expression in chronically infected cell lines were measured in samples from adults, cord blood, and neonates from Zaire and North America. Plasma levels of TNF alpha were higher in Zairian neonates born to HIV-negative and -positive mothers than in uninfected Zairian adults (612 vs. 128 vs. 8 pg/mL, P < .001); this dichotomy persisted until children were 9 months old. Plasmas from neonates of HIV-negative Zairian mothers also stimulated higher levels of reverse transcriptase from HIV-infected cell lines than did plasma from HIV-negative Zairian adults (1339 vs. 110 cpm, P < .001). Similar patterns were noted in plasmas from HIV-negative North American adults and neonates; however, TNF alpha levels were markedly lower, and smaller differences were noted among North American adults and neonates than those in the Zairian cohort. Markedly elevated plasma TNF alpha levels in Zairian neonates and infants may play a role in the pathogenesis and progression of HIV disease in this patient population.
 ...
PMID:Elevated levels of tumor necrosis factor-alpha in Zairian neonate plasmas: implications for perinatal infection with the human immunodeficiency virus. 816 28


<< Previous 1 2 3 4 5 6 7 8 9 10