Effect of Antibody to HIV-1 Tat Protein on Viral Replication in Vitro and Progression of HIV-1 Disease in Vivo

1995 ◽  
Vol 10 (4) ◽  
pp. 408-416 ◽  
Author(s):  
M C Re ◽  
G Furlini ◽  
M Vignoli ◽  
E Ramazzotti ◽  
G Roderigo ◽  
...  
Keyword(s):  
Viral Replication ◽  
Tat Protein ◽  
Hiv 1

scholarly journals Nature, Position, and Frequency of Mutations Made in a Single Cycle of HIV-1 Replication

2010 ◽  
Vol 84 (19) ◽  
pp. 9864-9878 ◽  
Author(s):  
Michael E. Abram ◽  
Andrea L. Ferris ◽  
Wei Shao ◽  
W. Gregory Alvord ◽  
Stephen H. Hughes
Keyword(s):  
Viral Replication ◽  
Mutation Rate ◽  
Hot Spots ◽  
High Rate ◽  
Published Data ◽  
Single Cycle ◽  
Efficient System ◽  
Hiv 1

ABSTRACT There is considerable HIV-1 variation in patients. The extent of the variation is due to the high rate of viral replication, the high viral load, and the errors made during viral replication. Mutations can arise from errors made either by host DNA-dependent RNA polymerase II or by HIV-1 reverse transcriptase (RT), but the relative contributions of these two enzymes to the mutation rate are unknown. In addition, mutations in RT can affect its fidelity, but the effect of mutations in RT on the nature of the mutations that arise in vivo is poorly understood. We have developed an efficient system, based on existing technology, to analyze the mutations that arise in an HIV-1 vector in a single cycle of replication. A lacZα reporter gene is used to identify viral DNAs that contain mutations which are analyzed by DNA sequencing. The forward mutation rate in this system is 1.4 × 10−5 mutations/bp/cycle, equivalent to the retroviral average. This rate is about 3-fold lower than previously reported for HIV-1 in vivo and is much lower than what has been reported for purified HIV-1 RT in vitro. Although the mutation rate was not affected by the orientation of lacZα, the sites favored for mutations (hot spots) in lacZα depended on which strand of lacZα was present in the viral RNA. The pattern of hot spots seen in lacZα in vivo did not match any of the published data obtained when purified RT was used to copy lacZα in vitro.

scholarly journals In vitro and in vivo cleavage of HIV-1 RNA by new SOFA-HDV ribozymes and their potential to inhibit viral replication

RNA Biology ◽  
2011 ◽  
Vol 8 (2) ◽  
pp. 343-353 ◽  
Author(s):  
Sébastien Lainé ◽  
Robert J. Scarborough ◽  
Dominique Lévesque ◽  
Ludovic Didierlaurent ◽  
Kaitlin J. Soye ◽  
...  
Keyword(s):  
Viral Replication ◽  
Hiv 1

Platelet Derived CD154 Induced by Tat Contributes to HIV-1 Associated Autoimmune Thrombocytopenia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2669-2669
Author(s):  
Jianhui Wang ◽  
Wei Zhang ◽  
Zongdong Li
Keyword(s):  
Immune Response ◽  
Platelet Activation ◽  
Conflicts Of Interest ◽  
Calcium Flux ◽  
Tat Protein ◽  
Autoimmune Thrombocytopenia ◽  
Integrin Β3 ◽  
Hiv 1

Abstract Abstract 2669 Poster Board II-645 Enhanced platelet activation was reported in HIV-1 infected patients and strongly correlated with plasma viral load. The HIV-1 Tat protein is able to serve as a ligand of the integrin αvβ3 and several chemokine receptors (CCR2 and CCR3) and to induce downstream signaling in cells express those receptors but the effect of Tat on platelet activation has not been fully investigated yet. Activated platelets are known to express and release a variety of proteins that can modulate the immune system, and platelet derived CD154 is reportedly involved in the development of autoimmune thrombocytopenia. However, the full mechanism underlying HIV-1 induced platelet activation and the biological consequences are not completely understood. In this study, we demonstrate that Tat is able to interact with platelets and β3 integrin by S35 label Tat-platelet binding assay and GST-Tat protein pull-down. We then show that Tat is able to induce platelet activation, up-regulates both CD62P and CD154 in both mouse and human platelets, and results in micro-particle release (as demonstrated by electron microscopy). Tat induces greatly diminished activation in integrin β3 knock out platelets or in platelets pretreated with CCR3 or calcium flux inhibitors, suggesting the requirement of chemokine receptor CCR3, integrin β3 and calcium flux for Tat induced platelet activation. The effect of Tat induced platelet activation on the immune response was studied both in vitro and in vivo. An enhanced immunoglobulin class switch was found in mouse spleen B cells co-cultured with platelets treated with Tat in vitro. In addition, an early antibody response against adenovirus was found in Tat injected mouse immunized with adenovirus suggesting an enhanced immune response in vivo. Thus, we have described a new mechanism in which Tat is able to induce platelet activation and have generated a model in which platelet activation can contribute to the development of HIV-1 associated thrombocytopenia. Disclosures: No relevant conflicts of interest to declare.

scholarly journals In Vivo Evidence for Instability of Episomal Human Immunodeficiency Virus Type 1 cDNA

2005 ◽  
Vol 79 (8) ◽  
pp. 5203-5210 ◽  
Author(s):  
Mark Sharkey ◽  
Karine Triques ◽  
Daniel R. Kuritzkes ◽  
Mario Stevenson
Keyword(s):  
Viral Replication ◽  
In Vitro Experiments ◽  
Plasma Viremia ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Current regimens for the management of human immunodeficiency virus type 1 (HIV-1) infection suppress plasma viremia to below detectable levels for prolonged intervals. Nevertheless, there is a rapid resumption in plasma viremia if therapy is interrupted. Attempts to characterize the extent of viral replication under conditions of potent suppression and undetectable plasma viremia have been hampered by a lack of convenient assays that can distinguish latent from ongoing viral replication. Using episomal viral cDNA as a surrogate for ongoing replication, we previously presented evidence that viral replication persists in the majority of infected individuals with a sustained aviremic status. The labile nature of viral episomes and hence their validity as surrogate markers of ongoing replication in individuals with long-term-suppressed HIV-1 infection have been analyzed in short-term in vitro experiments with conflicting results. Since these in vitro experiments do not shed light on the long-term in vivo dynamics of episomal cDNA or recapitulate the natural targets of infection in vivo, we have analyzed the dynamics of episomal cDNA turnover in vivo by following the emergence of an M184V polymorphism in plasma viral RNA, in episomal cDNA, and in proviral DNA in patients on suboptimal therapies. We demonstrate that during acquisition of drug resistance, wild-type episomal cDNAs are replaced by M184V-harboring episomes. Importantly, a complete replacement of wild-type episomes with M184V-containing episomes occurred while proviruses remained wild type. This indicates that episomal cDNAs are turned over by degradation rather than through death or tissue redistribution of the infected cell itself. Therefore, evolution of episomal viral cDNAs is a valid surrogate of ongoing viral replication in HIV-1-infected individuals.

Inhibition of HIV-1 Tat-Induced Interleukin-10 Expression by Mononuclear Cells at 3% O2.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2282-2282
Author(s):  
Amanuel Edossa ◽  
Victor R. Gordeuk ◽  
Sergei Nekhai
Keyword(s):  
Mononuclear Cells ◽  
Interleukin 10 ◽  
Cell Mediated Immunity ◽  
Inadequate Response ◽  
Tat Protein ◽  
Hiv Tat ◽  
Hiv 1 ◽  
Cells Cultured

Abstract The production of IL-10, which counteracts the effect of pro-inflammatory cytokines such as TNF-alpha, is induced by HIV-1 Tat in monocytes/macrophages by a process regulated by CREB-1 transcription factors [1]. IL-10 has been reported to suppress HIV-1 replication in macrophages by inhibiting HIV-1 transcription [2] at a, but it has also been reported to contribute to cell-mediated immunity in the setting of HIV infection [3]. We compared Tat-induced expression of IL-10 by THP-1 monocytes at 3% O2 (20 mmHg), the tension that monocytes see in certain tissues, and atmospheric 21% O2 (150 mmHg), the conventional in vitro culture condition. THP-1 cells were treated with recombinant HIV-Tat protein in combination with or without lipopolysaccharide (LPS) and IL-10 expression was analyzed by RT-PCR and ELISA. Treatment of THP-1 cells with HIV-Tat and LPS resulted in a dose- and time-dependent increase in IL-10 expression in the cells cultured at 21% O2. In contrast under 3% O2 the expression of IL-10 was reduced by 3-fold. Treatment with tautomycin, a protein phosphatase-1 (PP1) inhibitor, prevented IL-10 expression in LPS-stimulated THP-1 cells cultured at 21% O2. Thus, PP1 is likely to participate in Tat-mediated IL-10 production. PP1 has shown to affect CREB activity [4]; therefore we propose that PP1 might be involved in the CREB-mediated IL-10 gene expression. The inability of Tat to induce IL-10 production under 3% O2 might reflect the inadequate response of HIV-1 infected macrophages in vivo that might permit viral replication in infected macrophages. Further investigation of the role of PP1 in IL-10 expression could lead to new therapeutic opportunities for HIV-1 infection.

scholarly journals Discordance between Frequency of Human Immunodeficiency Virus Type 1 (HIV-1)-Specific Gamma Interferon-Producing CD4+ T Cells and HIV-1-Specific Lymphoproliferation in HIV-1-Infected Subjects with Active Viral Replication

2002 ◽  
Vol 76 (12) ◽  
pp. 5925-5936 ◽  
Author(s):  
B. E. Palmer ◽  
E. Boritz ◽  
N. Blyveis ◽  
C. C. Wilson
Keyword(s):  
T Cells ◽  
T Cell ◽  
Viral Replication ◽  
Th Cell ◽  
Immunodeficiency Virus ◽  
Active Viral Replication ◽  
Hiv 1

ABSTRACT One hallmark of uncontrolled, chronic human immunodeficiency virus type 1 (HIV-1) infection is the absence of strong HIV-1-specific, CD4+ T-cell-proliferative responses, yet the mechanism underlying this T helper (Th)-cell defect remains controversial. To better understand the impact of HIV-1 replication on Th-cell function, we compared the frequency of CD4+ Th-cell responses based on production of gamma interferon to lymphoproliferative responses directed against HIV-1 proteins in HIV-1-infected subjects with active in vivo viral replication versus those on suppressed highly active antiretroviral therapy (HAART). No statistically significant differences in the frequencies of cytokine-secreting, HIV-1-specific CD4+ T cells between the donor groups were found, despite differences in viral load and treatment status. However, HIV-1-specific lymphoproliferative responses were significantly greater in the subjects with HAART suppression than in subjects with active viral replication. Similar levels of HIV-1 RNA were measured in T-cell cultures stimulated with HIV-1 antigens regardless of donor in vivo viral loads, but only HIV-1-specific CD4+ T cells from subjects with HAART suppression proliferated in vitro, suggesting that HIV-1 replication in vitro does not preclude HIV-1-specific lymphoproliferation. This study demonstrates a discordance between the frequency and proliferative capacity of HIV-1-specific CD4+ T cells in subjects with ongoing in vivo viral replication and suggests that in vivo HIV-1 replication contributes to the observed defect in HIV-1-specific CD4+ T-cell proliferation.

scholarly journals Promiscuous targeting of cellular proteins by Vpr drives massive proteomic remodelling in HIV-1 infection

2018 ◽  
Author(s):  
Edward JD Greenwood ◽  
James C Williamson ◽  
Agata Sienkiewicz ◽  
Adi Naamati ◽  
Nicholas J Matheson ◽  
...  
Keyword(s):  
Viral Replication ◽  
Biological Significance ◽  
Cellular Proteins ◽  
M Cell ◽  
Cellular Targets ◽  
Host Restriction ◽  
Cellular Phenotypes ◽  
Hiv 1

AbstractHIV-1 encodes four ‘accessory proteins’ (Vif, Vpr, Vpu and Nef), dispensable for viral replication in vitro, but essential for viral pathogenesis in vivo. Well characterised cellular targets have been associated with Vif, Vpu and Nef, which counteract host restriction and promote viral replication. Conversely, whilst several substrates of Vpr have been described, their biological significance remains unclear. Here, we use complementary, unbiased mass spectrometry-based approaches to demonstrate that Vpr is both necessary and sufficient for DCAF1/DDB1/CUL4 E3 ubiquitin ligase-mediated degradation of at least 38 cellular proteins, causing systems-level changes to the cellular proteome. We therefore propose that promiscuous targeting of multiple host factors underpins complex Vpr-dependent cellular phenotypes, and validate this in the case of G2/M cell cycle arrest. Our model explains how Vpr modulates so many cell biological processes, and why the functional consequences of previously described Vpr targets, identified and studied in isolation, have proved elusive.

scholarly journals Two-long terminal repeat (LTR) DNA circles are a substrate for HIV-1 integrase

2019 ◽  
Vol 294 (20) ◽  
pp. 8286-8295 ◽  
Author(s):  
Clémence Richetta ◽  
Sylvain Thierry ◽  
Eloise Thierry ◽  
Paul Lesbats ◽  
Delphine Lapaillerie ◽  
...  
Keyword(s):  
Viral Replication ◽  
Long Terminal Repeat ◽  
Terminal Repeat ◽  
Host Genome ◽  
End Joining ◽  
Viral Dna ◽  
Retroviral Integrase ◽  
Hiv 1

Integration of the HIV-1 DNA into the host genome is essential for viral replication and is catalyzed by the retroviral integrase. To date, the only substrate described to be involved in this critical reaction is the linear viral DNA produced in reverse transcription. However, during HIV-1 infection, two-long terminal repeat DNA circles (2-LTRcs) are also generated through the ligation of the viral DNA ends by the host cell's nonhomologous DNA end-joining pathway. These DNAs contain all the genetic information required for viral replication, but their role in HIV-1's life cycle remains unknown. We previously showed that both linear and circular DNA fragments containing the 2-LTR palindrome junction can be efficiently cleaved in vitro by recombinant integrases, leading to the formation of linear 3′-processed–like DNA. In this report, using in vitro experiments with purified proteins and DNAs along with DNA endonuclease and in vivo integration assays, we show that this circularized genome can also be efficiently used as a substrate in HIV-1 integrase-mediated integration both in vitro and in eukaryotic cells. Notably, we demonstrate that the palindrome cleavage occurs via a two-step mechanism leading to a blunt-ended DNA product, followed by a classical 3′-processing reaction; this cleavage leads to integrase-dependent integration, highlighted by a 5-bp duplication of the host genome. Our results suggest that 2-LTRc may constitute a reserve supply of HIV-1 genomes for proviral integration.

scholarly journals HIV-1 establishes a sanctuary site in the testis by permeating the BTB through changes in cytoskeletal organization

Endocrinology ◽  
2021 ◽  
Author(s):  
Siwen Wu ◽  
Ines Frank ◽  
Nina Derby ◽  
Elena Martinelli ◽  
C Yan Cheng
Keyword(s):  
Sertoli Cell ◽  
Sertoli Cells ◽  
Underlying Mechanism ◽  
Antiretroviral Drugs ◽  
Permeability Barrier ◽  
Tat Protein ◽  
Vitro Model ◽  
Hiv 1

Abstract Studies suggest that HIV-1 invades the testis through permeation of the blood-testis barrier (BTB). The selectivity of the BTB to antiretroviral drugs makes this site a sanctuary for the virus. Little is known about how HIV-1 crosses the BTB and invades the testis. Herein, we used two approaches to examine the underlying mechanism(s) by which HIV-1 permeates the BTB and gains entry into the seminiferous epithelium. First, we examined if recombinant Tat protein was capable of perturbing the BTB and making the barrier leaky, using the primary rat Sertoli cell in vitro model that mimics the BTB in vivo. Second, we used HIV-1 infected Sup-T1 cells to investigate the activity of HIV-1 infection on co-cultured Sertoli cells. Using both approaches, we found that the Sertoli cell tight junction (TJ)-permeability barrier was considerably perturbed and that HIV-1 effectively permeates the BTB by inducing actin-, microtubule-, vimentin- and septin-based cytoskeletal changes in Sertoli cells. These studies suggest that HIV-1 directly perturbs BTB function, potentially through the activity of the Tat protein.

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