The Experts below are selected from a list of 1005 Experts worldwide ranked by ideXlab platform
Anthony S Fauci - One of the best experts on this subject based on the ideXlab platform.
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Human Immunodeficiency Virus Expression and Replication in Infected Cells of the
2013Co-Authors: Guido Poli, Peter Bressler, Jesse S Justement, John H Kehrl, Audrey L Kinter, Anthony S FauciAbstract:The pleiotropic immunoregulatory cytokine transforming growth factor # (TGF-,l3) potently suppresses production of the human immunodeficiency virus (HIV), the causative agent of the acquired immunodeficiency syndrome, in the chronically infected Promonocytic Cell line U1. TGF-O significantly (50-90%) inhibited HIV reverse transcriptase production and synthesis of viral proteins in U1 Cells stimulated with phorbol myristate acetate (PMA) or interleukin 6 (IIr6). Furthermore, TGF-IQ suppressed PMA induction of HIV transcription in U1 Cells. In contrast, TGF-O did not significantly affect the expression of HIV induced by tumor necrosis factor ct (TNF-ci). These suppressive effects were not mediated via the induction of interferon a (IFN-tx). TGF-0 also suppressed HIV replication in primary monocyte-derived macrophages infected in vitro, both in the absence of exogenous cytokines and in IL6-stimulated cultures. In contrast, no significant effects of TGF-i8 were observed in either a chronically infected T Cell line (ACH-2) or in primary T Cell blasts infected in vitro. Therefore, TGF-a may play a potentially important role as a negative regulator of HIV expression in infected monocytes or tissue macrophages in infected individuals. number of cytokines, including TNF-ci or- fl, 11,2, IL6.L IL and granulocyte/macrophage colony-stimulating facto
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Activated B Lymphocytes from Human Immunodeficiency Virus-infected Individuals Induce Virus Expression in Infected T Cells and
2013Co-Authors: Promonocytic Cell A Line, Peter Rieckmann, Guido Poli, John H Kehrl, Anthony S FauciAbstract:Freshly isolated B lymphocytes from patients infected with human immunodeficiency virus (HIV), in contrast to B Cells from normal controls, were shown to induce viral expression in two Cell lines: ACH-2, a T Cell line, and Ul, a Promonocytic Cell line, which are chronically infected with HIV, as well as in autologous T Cells. In 10 out of 10 HIV infected individuals with hypergammaglobulinemia, spontaneous HIV-inductive capacity was found with highly purified peripheral blood B Cells, whereas peripheral blood or tonsillar B Cells from six healthy, HIV negative donors did not induce HIV expression unless the Cells were stimulated in vitro. The induction of HIV expression was observed in direct coculture experiments of B lymphocytes and HIVinfected Cells, and could also be mediated by supernatants from cultures of B Cells. Significantly higher amounts of interleukin 6 (IL6) and tumor necrosis factor a (TNF-a) were detected in the B Cell culture supernatants from HIVinfected patients with hypergammaglobulinemia (IL-6: z = 536 pg/ml; TNF-a: x = 493 pg/ml), as compared with normal uninfected controls (IL-6: x = 18 pg/ml; TNF-a: z = 23 pg/ml). Antibodies against these cytokines abolished the HIV-inductive capacity of B Cells. We conclude that in vivo activated B Cells in HIVinfected individuals can upregulate the expression of virus in infected Cells by secreting cytokines suc
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Promonocytic u937 subclones expressing cd4 and cxcr4 are resistant to infection with and Cell to Cell fusion by t Cell tropic human immunodeficiency virus type 1
Journal of Virology, 1997Co-Authors: Hiroyuki Moriuchi, Masako Moriuchi, James Arthos, James A Hoxie, Anthony S FauciAbstract:Different strains of human immunodeficiency virus type 1 (HIV-1) vary markedly in the ability to infect Cells of the monocyte/macrophage (M/M) lineage. M/M are generally resistant to infection with T-Cell-tropic (T-tropic) strains of HIV-1. Recently, the chemokine receptors CCR5 and CXCR4 were identified as cofactors for fusion/entry of macrophage- and T-tropic strains of HIV-1, respectively. To investigate the mechanisms of resistance of M/M to T-tropic HIV-1 infection, we examined a number of subclones of the U937 Promonocytic Cell line. We found that certain subclones of U937 (plus clones) could, while others (minus clones) could not, support replication of T-tropic strains of HIV-1. We demonstrate that (i) both minus and plus clones support HIV-1 replication when transfected with an infectious molecular cDNA clone of a T-tropic HIV-1; (ii) minus clones do not, but plus clones do, efficiently support fusion with Cells expressing HIV-1 IIIB Env; (iii) both plus and minus clones (with the exception of one clone) express physiologically functional CXCR4 protein as well as CD4 on the Cell surface; (iv) introduction of CXCR4 into the CXCR4-negative clone does not restore fusogenicity with or susceptibility to T-tropic HIV-1; and (v) a ligand (stromal Cell-derived factor 1) for or a monoclonal antibody (12G5) to CXCR4 does not effectively inhibit HIV-mediated Cell-to-Cell fusion of U937 Cells. These data indicate that resistance to T-tropic HIV-1 infection of U937 minus clones occurs at fusion/ entry events and that expression of functional CXCR4 and CD4 is not a sole determinant for susceptibility to T-tropic HIV-1 infection; furthermore, they suggest that other factors are positively or negatively involved in HIV-mediated Cell-to-Cell fusion in U937 Promonocytic Cells.
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the chronically infected Promonocytic Cell line u1 a model of hiv expression regulated by cytokines
Immunomethods, 1993Co-Authors: Guido Poli, Priscilla Biswas, Sharilyn K Stanley, Peter Bressler, Jesse S Justement, Audrey Kinter, Drew Weissman, Lawrence Fox, Delia Goletti, Anthony S FauciAbstract:Abstract Infection with the human immunodeficiency virus (HIV) causes the acquired immunodeficiency syndrome (AIDS) over a medium period of 10 years. During this time Cells that actively express HIV and Cells that harbor the virus in a latent form have been demonstrated in different tissues and organs of infected individuals. It is critical to delineate the Cellular and/or viral factors that regulate HIV expression and latency in order to fully understand the pathogenic mechanisms of HIV disease. Among several in vitro models that have been developed since HIV has been recognized as a human pathogen, the chronically infected Promonocytic Cell line U1 has become one of the more broadly used surrogate models for studies of immunologic and molecular regulation of HIV expression. In particular, more than 10 different cytokines have been shown to up- or down-regulate virus production in U1 Cells either alone or in synergistic combination. Autocrine/paracrine induction of HIV expression was first demonstrated in this Cell line, anticipating results in more complex models of virus infection. In addition to cytokines, hormones, vitamins, and physical and chemical agents, including UV light, heat, and reactive oxygen intermediates, have been shown to reactivate quiescent integrated proviruses. Finally, U1 Cells have been used as standard controls for polymerase chain reaction studies, for pharmacologic screening of potentially therapeutic agents, and as a convenient multicytokine bioassay system for studies of immunologic control of HIV expression.
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glucocorticoids synergize with tumor necrosis factor α in the induction of hiv expression from a chronically infected Promonocytic Cell line
AIDS Research and Human Retroviruses, 1993Co-Authors: Peter Bressler, Priscilla Biswas, Guido Poli, Jesse S Justement, Anthony S FauciAbstract:In this study we have investigated the effects of glucocorticoids (GCs) on the expression of human immunodeficiency virus (HIV) in a chronically infected Promonocytic Cell line, U1. Although no increase in virus production was observed in U1 Cells stimulated with physiological concentrations of GC alone, costimulation with dexamethasone plus tumor necrosis factor α (TNF-α) synergistically enhanced TNF-α-dependent HIV expression. Molecular analysis demonstrated that GCs plus TNF-α resulted in an accumulation of steady state HIV RNA secondary to either an increase in transcription or an increase in message stability. These findings may be of physiological relevance because GCs are used in the treatment of certain disorders associated with HIV infection and TNF-α levels have been reported to be elevated in the plasma and cerebrospinal fluid of certain HIV-infected individuals.
Masao Takata - One of the best experts on this subject based on the ideXlab platform.
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reactive oxygen species and p38 mitogen activated protein kinase mediate tumor necrosis factor α converting enzyme tace adam 17 activation in primary human monocytes
Journal of Biological Chemistry, 2011Co-Authors: Alasdair J Scott, Kieran P Odea, David Ocallaghan, L C Williams, Justina O Dokpesi, Louise Tatton, J M Handy, Philip J Hogg, Masao TakataAbstract:Tumor necrosis factor α-converting enzyme (TACE) is responsible for the shedding of Cell surface TNF. Studies suggest that reactive oxygen species (ROS) mediate up-regulation of TACE activity by direct oxidization or modification of the protein. However, these investigations have been largely based upon nonphysiological stimulation of Promonocytic Cell lines which may respond and process TACE differently from primary Cells. Furthermore, investigators have relied upon TACE substrate shedding as a surrogate for activity quantification. We addressed these concerns, employing a direct, Cell-based fluorometric assay to investigate the regulation of TACE catalytic activity on freshly isolated primary human monocytes during LPS stimulation. We hypothesized that ROS mediate up-regulation of TACE activity indirectly, by activation of intraCellular signaling pathways. LPS up-regulated TACE activity rapidly (within 30 min) without changing Cell surface TACE expression. Scavenging of ROS or inhibiting their production by flavoprotein oxidoreductases significantly attenuated LPS-induced TACE activity up-regulation. Exogenous ROS (H2O2) also up-regulated TACE activity with similar kinetics and magnitude as LPS. H2O2- and LPS-induced TACE activity up-regulation were effectively abolished by a variety of selective p38 MAPK inhibitors. Activation of p38 was redox-sensitive as H2O2 caused p38 phosphorylation, and ROS scavenging significantly reduced LPS-induced phospho-p38 expression. Inhibition of the p38 substrate, MAPK-activated protein kinase 2, completely attenuated TACE activity up-regulation, whereas inhibition of ERK had little effect. Lastly, inhibition of Cell surface oxidoreductases prevented TACE activity up-regulation distal to p38 activation. In conclusion, our data indicate that in primary human monocytes, ROS mediate LPS-induced up-regulation of TACE activity indirectly through activation of the p38 signaling pathway.
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reactive oxygen species and p38 mitogen activated protein kinase mediate tumor necrosis factor α converting enzyme tace adam 17 activation in primary human monocytes
Journal of Biological Chemistry, 2011Co-Authors: Alasdair Scott, Kieran P Odea, David Ocallaghan, Justina O Dokpesi, Louise Tatton, Philip J Hogg, Lynn M Williams, Jonathan Handy, Masao TakataAbstract:Tumor necrosis factor α-converting enzyme (TACE) is responsible for the shedding of Cell surface TNF. Studies suggest that reactive oxygen species (ROS) mediate up-regulation of TACE activity by direct oxidization or modification of the protein. However, these investigations have been largely based upon nonphysiological stimulation of Promonocytic Cell lines which may respond and process TACE differently from primary Cells. Furthermore, investigators have relied upon TACE substrate shedding as a surrogate for activity quantification. We addressed these concerns, employing a direct, Cell-based fluorometric assay to investigate the regulation of TACE catalytic activity on freshly isolated primary human monocytes during LPS stimulation. We hypothesized that ROS mediate up-regulation of TACE activity indirectly, by activation of intraCellular signaling pathways. LPS up-regulated TACE activity rapidly (within 30 min) without changing Cell surface TACE expression. Scavenging of ROS or inhibiting their production by flavoprotein oxidoreductases significantly attenuated LPS-induced TACE activity up-regulation. Exogenous ROS (H2O2) also up-regulated TACE activity with similar kinetics and magnitude as LPS. H2O2- and LPS-induced TACE activity up-regulation were effectively abolished by a variety of selective p38 MAPK inhibitors. Activation of p38 was redox-sensitive as H2O2 caused p38 phosphorylation, and ROS scavenging significantly reduced LPS-induced phospho-p38 expression. Inhibition of the p38 substrate, MAPK-activated protein kinase 2, completely attenuated TACE activity up-regulation, whereas inhibition of ERK had little effect. Lastly, inhibition of Cell surface oxidoreductases prevented TACE activity up-regulation distal to p38 activation. In conclusion, our data indicate that in primary human monocytes, ROS mediate LPS-induced up-regulation of TACE activity indirectly through activation of the p38 signaling pathway.
Mark V. Coggeshall - One of the best experts on this subject based on the ideXlab platform.
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black walnut juglans nigra extracts inhibit proinflammatory cytokine production from lipopolysaccharide stimulated human Promonocytic Cell line u 937
Frontiers in Pharmacology, 2019Co-Authors: Khanhvan Ho, Kathy L Schreiber, Danh C Vu, Susan M Rottinghaus, Daniel E Jackson, Lloyd W Sumner, Charles R Brown, Mark V. CoggeshallAbstract:Black walnut (Juglans nigra L.) is an exCellent source of health-promoting compounds. Consumption of black walnuts has been linked to many health benefits (e.g., anti-inflammatory) stemming from its phytochemical composition and medicinal properties, but these effects have not been systematically studied or characterized. In this study, potential anti-inflammatory compounds found in kernel extracts of ten black walnut cultivars were putatively identified using a metabolomics profiling analysis, revealing differences in potential anti-inflammatory capacities among examined cultivars. Five cultivars were examined for activities in the human pro-monocytic Cell line U-937 by evaluating the effects of the extracts on the expression of 6 human inflammatory cytokines/chemokines using a bead-based, flow cytometric multiplex assay. The methanolic extracts of these cultivars were added at four concentrations (0.1, 0.3, 1, and 10 mg/mL) either before and after the addition of lipopolysaccharide (LPS) to human U-937 Cells to examine their effect on cytokine production. Results from cytotoxicity and viability assays revealed that the kernel extracts had no toxic effect on the U-937 Cells. Of the 13 cytokines (IL-1β, TNF-α, MCP-1, IL-6, IL-8, IL-10, IL-12, IL-17, IL-18, IL-23, IL-33, IFN-α, IFN-γ) measured, only 6 were detected under the culture conditions. The production of the six detected cytokines by PMA-differentiated, LPS-stimulated U-937 was significantly inhibited by the kernel extracts from two cultivars Surprise and Sparrow when the extracts were added prior to the addition of LPS. Other cultivars (Daniel, Mystry, and Sparks) showed weak or no significant effects on cytokine production. In contrast, no inhibitory effect was observed on the production of cytokines by PMA-differentiated, LPS-stimulated U-937 when the kernel extracts were added after the addition of LPS. The findings suggest that the extracts from certain black walnut cultivars, such as Sparrow and Surprise, are promising biologic candidates for potentially decreasing the severity of inflammatory disease.
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black walnut juglans nigra extracts inhibit proinflammatory cytokine production from lipopolysaccharide stimulated human Promonocytic Cell line u 937
Frontiers in Pharmacology, 2019Co-Authors: Kathy L Schreiber, Susan M Rottinghaus, Daniel E Jackson, Mark V. Coggeshall, Lloyd W Sumner, Charles R Brown, Zhentian Lei, Chungho LinAbstract:Black walnut (Juglans nigra L.) is an exCellent source of health-promoting compounds. Consumption of black walnuts has been linked to many health benefits (e.g., anti-inflammatory) stemming from its phytochemical composition and medicinal properties, but these effects have not been systematically studied or characterized. In this study, potential anti-inflammatory compounds found in kernel extracts of 10 black walnut cultivars were putatively identified using a metabolomic profiling analysis, revealing differences in potential anti-inflammatory capacities among examined cultivars. Five cultivars were examined for activities in the human Promonocytic Cell line U-937 by evaluating the effects of the extracts on the expression of six human inflammatory cytokines/chemokines using a bead-based, flow cytometric multiplex assay. The methanolic extracts of these cultivars were added at four concentrations (0.1, 0.3, 1, and 10 mg/ml) either before and after the addition of lipopolysaccharide (LPS) to human U-937 Cells to examine their effect on cytokine production. Results from cytotoxicity and viability assays revealed that the kernel extracts had no toxic effect on the U-937 Cells. Of the 13 cytokines [interleukin (IL)-1β, tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein (MCP)-1, IL-6, IL-8, IL-10, IL-12, IL-17, IL-18, IL-23, IL-33, interferon (IFN)-α, IFN-γ] measured, only six were detected under the culture conditions. The production of the six detected cytokines by phorbol 12-myristate 13-acetate (PMA)-differentiated, LPS-stimulated U-937 was significantly inhibited by the kernel extracts from two cultivars Surprise and Sparrow when the extracts were added before the addition of LPS. Other cultivars (Daniel, Mystry, and Sparks) showed weak or no significant effects on cytokine production. In contrast, no inhibitory effect was observed on the production of cytokines by PMA-differentiated, LPS-stimulated U-937 when the kernel extracts were added after the addition of LPS. The findings suggest that the extracts from certain black walnut cultivars, such as Sparrow and Surprise, are promising biological candidates for potentially decreasing the severity of inflammatory disease.
Khanhvan Ho - One of the best experts on this subject based on the ideXlab platform.
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black walnut juglans nigra extracts inhibit proinflammatory cytokine production from lipopolysaccharide stimulated human Promonocytic Cell line u 937
Frontiers in Pharmacology, 2019Co-Authors: Khanhvan Ho, Kathy L Schreiber, Danh C Vu, Susan M Rottinghaus, Daniel E Jackson, Lloyd W Sumner, Charles R Brown, Mark V. CoggeshallAbstract:Black walnut (Juglans nigra L.) is an exCellent source of health-promoting compounds. Consumption of black walnuts has been linked to many health benefits (e.g., anti-inflammatory) stemming from its phytochemical composition and medicinal properties, but these effects have not been systematically studied or characterized. In this study, potential anti-inflammatory compounds found in kernel extracts of ten black walnut cultivars were putatively identified using a metabolomics profiling analysis, revealing differences in potential anti-inflammatory capacities among examined cultivars. Five cultivars were examined for activities in the human pro-monocytic Cell line U-937 by evaluating the effects of the extracts on the expression of 6 human inflammatory cytokines/chemokines using a bead-based, flow cytometric multiplex assay. The methanolic extracts of these cultivars were added at four concentrations (0.1, 0.3, 1, and 10 mg/mL) either before and after the addition of lipopolysaccharide (LPS) to human U-937 Cells to examine their effect on cytokine production. Results from cytotoxicity and viability assays revealed that the kernel extracts had no toxic effect on the U-937 Cells. Of the 13 cytokines (IL-1β, TNF-α, MCP-1, IL-6, IL-8, IL-10, IL-12, IL-17, IL-18, IL-23, IL-33, IFN-α, IFN-γ) measured, only 6 were detected under the culture conditions. The production of the six detected cytokines by PMA-differentiated, LPS-stimulated U-937 was significantly inhibited by the kernel extracts from two cultivars Surprise and Sparrow when the extracts were added prior to the addition of LPS. Other cultivars (Daniel, Mystry, and Sparks) showed weak or no significant effects on cytokine production. In contrast, no inhibitory effect was observed on the production of cytokines by PMA-differentiated, LPS-stimulated U-937 when the kernel extracts were added after the addition of LPS. The findings suggest that the extracts from certain black walnut cultivars, such as Sparrow and Surprise, are promising biologic candidates for potentially decreasing the severity of inflammatory disease.
Guido Poli - One of the best experts on this subject based on the ideXlab platform.
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Open AccessPoster presentation Naturally C-Terminally truncated STAT5 (STAT5Δ): a novel
2016Co-Authors: Giulia Della Chiara, Guido Poli, Andrea Crotti, Mauro Giacca, Della Chiara Giulia, Tinelli Marco, Lazzarin Adriano, Bruce K, Giacca Mauro, Bovolenta ChiaraAbstract:We have previously observed that signal transducers and activator of transcription (STAT) proteins, namely STAT1 and STAT5, are often constitutively activated in the PBMC of most of HIV-1+ individuals; furthermore, most patients are characterized by the dominant expression of a C-ter-minally truncated isoform of STAT5 (STAT5Δ) [1]. STAT5Δ is also the prevalent isoform of STAT5 found in the chronically HIV-1 infected Promonocytic Cell line U1, characterized by a constitutive state of viral latency and inducibility of virus expression by PMA or several cytokines. We recently reported that activated STAT5Δ can act as a negative regulator of HIV-1 expression in GM-CSF stimulated U1 Cells and IL-2-stimulated PBMCs. Indeed, in U1 Cells we have shown that activated STAT5Δ can directly in vivo bind to STAT consensus sequences in th
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Human Immunodeficiency Virus Expression and Replication in Infected Cells of the
2013Co-Authors: Guido Poli, Peter Bressler, Jesse S Justement, John H Kehrl, Audrey L Kinter, Anthony S FauciAbstract:The pleiotropic immunoregulatory cytokine transforming growth factor # (TGF-,l3) potently suppresses production of the human immunodeficiency virus (HIV), the causative agent of the acquired immunodeficiency syndrome, in the chronically infected Promonocytic Cell line U1. TGF-O significantly (50-90%) inhibited HIV reverse transcriptase production and synthesis of viral proteins in U1 Cells stimulated with phorbol myristate acetate (PMA) or interleukin 6 (IIr6). Furthermore, TGF-IQ suppressed PMA induction of HIV transcription in U1 Cells. In contrast, TGF-O did not significantly affect the expression of HIV induced by tumor necrosis factor ct (TNF-ci). These suppressive effects were not mediated via the induction of interferon a (IFN-tx). TGF-0 also suppressed HIV replication in primary monocyte-derived macrophages infected in vitro, both in the absence of exogenous cytokines and in IL6-stimulated cultures. In contrast, no significant effects of TGF-i8 were observed in either a chronically infected T Cell line (ACH-2) or in primary T Cell blasts infected in vitro. Therefore, TGF-a may play a potentially important role as a negative regulator of HIV expression in infected monocytes or tissue macrophages in infected individuals. number of cytokines, including TNF-ci or- fl, 11,2, IL6.L IL and granulocyte/macrophage colony-stimulating facto
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Activated B Lymphocytes from Human Immunodeficiency Virus-infected Individuals Induce Virus Expression in Infected T Cells and
2013Co-Authors: Promonocytic Cell A Line, Peter Rieckmann, Guido Poli, John H Kehrl, Anthony S FauciAbstract:Freshly isolated B lymphocytes from patients infected with human immunodeficiency virus (HIV), in contrast to B Cells from normal controls, were shown to induce viral expression in two Cell lines: ACH-2, a T Cell line, and Ul, a Promonocytic Cell line, which are chronically infected with HIV, as well as in autologous T Cells. In 10 out of 10 HIV infected individuals with hypergammaglobulinemia, spontaneous HIV-inductive capacity was found with highly purified peripheral blood B Cells, whereas peripheral blood or tonsillar B Cells from six healthy, HIV negative donors did not induce HIV expression unless the Cells were stimulated in vitro. The induction of HIV expression was observed in direct coculture experiments of B lymphocytes and HIVinfected Cells, and could also be mediated by supernatants from cultures of B Cells. Significantly higher amounts of interleukin 6 (IL6) and tumor necrosis factor a (TNF-a) were detected in the B Cell culture supernatants from HIVinfected patients with hypergammaglobulinemia (IL-6: z = 536 pg/ml; TNF-a: x = 493 pg/ml), as compared with normal uninfected controls (IL-6: x = 18 pg/ml; TNF-a: z = 23 pg/ml). Antibodies against these cytokines abolished the HIV-inductive capacity of B Cells. We conclude that in vivo activated B Cells in HIVinfected individuals can upregulate the expression of virus in infected Cells by secreting cytokines suc
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trim22 inhibits hiv 1 transcription independently of its e3 ubiquitin ligase activity tat and nf κb responsive long terminal repeat elements
Journal of Virology, 2011Co-Authors: Anna Kajasterudnitski, Guido Poli, Sara S Marelli, Cinzia Pultrone, Thomas Pertel, Pradeep D Uchil, Nadir Mechti, Walther Mothes, Jeremy Luban, Elisa VicenziAbstract:Previous studies identified clones of the U937 Promonocytic Cell line that were either permissive or nonpermissive for human immunodeficiency virus type 1 (HIV-1) replication. These clones were investigated further in the search for host restriction factors that could explain their differential capacity to support HIV-1 replication. Among known HIV-1 restriction factors screened, tripartite motif-containing protein 22 (TRIM22) was the only factor constitutively expressed in nonpermissive and absent in permissive U937 Cells. Stable TRIM22 knockdown (KD) rescued HIV-1 long-terminal-repeat (LTR)-driven transcription in KD-nonpermissive Cells to the levels observed in permissive Cells. Conversely, transduction-mediated expression of TRIM22 in permissive Cells reduced LTR-driven luciferase expression by ∼7-fold, supporting a negative role of TRIM22 in HIV-1 transcription. This finding was further confirmed in the human T Cell line A3.01 expressing TRIM22. Moreover, overexpression of TRIM22 in 293T Cells significantly impaired basal and phorbol myristate acetate-ionomycin-induced HIV-1 LTR-driven gene expression, whereas inhibition of tumor necrosis factor alpha-induced viral transcription was a consequence of lower basal expression. In agreement, TRIM22 equally inhibited an LTR construct lacking the tandem NF-κB binding sites. In addition, TRIM22 did not affect Tat-mediated LTR transactivation. Finally, these effects were independent of TRIM22 E3 ubiquitin-ligase activity. In the context of replication-competent virus, significantly higher levels of HIV-1 production were observed in KD-nonpermissive versus control nonpermissive U937 Cells after infection. In contrast, lower peak levels of HIV-1 replication characterized U937 and A3.01 Cells expressing TRIM22 versus their control transduced counterpart. Thus, nuclear TRIM22 significantly impairs HIV-1 replication, likely by interfering with Tat- and NF-κB-independent LTR-driven transcription.
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interleukin 10 induced hiv 1 expression is mediated by induction of both membrane bound tumour necrosis factor tnf alpha and tnf receptor type 1 in a Promonocytic Cell line
AIDS, 1996Co-Authors: Wilma Barcellini, Guido Poli, G P Rizzardi, J B Marriott, C Fain, Robin J Shattock, Pier Luigi Meroni, Angus G DalgleishAbstract:OBJECTIVE To investigate whether the upregulatory effect of interleukin (IL)-10 on HIV expression in a model of latent HIV infection is mediated by induction of endogenous tumour necrosis factor (TNF)-alpha and TNF receptors (TNFR). DESIGN The latently HIV-infected Promonocytic Cell line U1 was examined, because in this in vitro model IL-10 has been shown to synergize with multiple cytokines, including TNF-alpha, in enhancing HIV production. METHODS Membrane-bound TNF-alpha, TNFR-1 and TNFR-2 surface expression were determined by flow cytometry. TNF-alpha mRNA was estimated by competitive polymerase chain reaction (PCR), and TNF-alpha, soluble TNFR-1 and soluble TNFR-2 supernatant content by enzyme-linked immunosorbent assay. HIV-1 expression was quantitated by reverse transcriptase assay and p24 antigen release. RESULTS We demonstrated that IL-10 induces a time and Cell-concentration dependent upregulation of HIV expression in U1 Cells. This effect is mediated through the endogenous production of TNF-alpha as demonstrated by blocking experiments with anti-TNF-alpha antibodies and by detection of IL-10-induced increase of TNF-alpha mRNA by competitive PCR. More importantly, IL-10 is able to upregulate membrane-bound TNF-alpha and TNFR-1, along with a consistent increase in the shedding of soluble TNFR-1 without inducing detectable TNF-alpha secretion. CONCLUSIONS IL-10 activates HIV expression through the membrane-bound TNF-alpha/TNFR-1 pathway, suggesting an amplification mechanism of HIV expression that might occur during Cell-to-Cell interaction. This positive regulatory effect of IL-10 in an in vitro model of chronic HIV infection is consistent with the inexorable progression of disease seen in advanced patients when both IL-10 and TNF-alpha are elevated.
