Ephedrine enhances HIV-1 reactivation from latency through elevating tumor necrosis factor receptor II (TNFRII) expression.
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ABSTRACT:
SUBMITTER: Panaampon J
PROVIDER: S-EPMC6819846 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:UnlabelledThe HIV-1 accessory protein Vpr displays different activities potentially impacting viral replication, including the arrest of the cell cycle in the G2 phase and the stimulation of apoptosis and DNA damage response pathways. Vpr also modulates cytokine production by infected cells, but this property remains partly characterized. Here, we investigated the effect of Vpr on the production of the proinflammatory cytokine tumor necrosis factor (TNF). We report that Vpr significantly increases TNF secretion by infected lymphocytes. De novo production of Vpr is required for this effect. Vpr mutants known to be defective for G2 cell cycle arrest induce lower levels of TNF secretion, suggesting a link between these two functions. Silencing experiments and the use of chemical inhibitors further implicated the cellular proteins DDB1 and TAK1 in this activity of Vpr. TNF secreted by HIV-1-infected cells triggers NF-?B activity in bystander cells and allows viral reactivation in a model of latently infected cells. Thus, the stimulation of the proinflammatory pathway by Vpr may impact HIV-1 replication in vivo.ImportanceThe role of the HIV-1 accessory protein Vpr remains only partially characterized. This protein is important for viral pathogenesis in infected individuals but is dispensable for viral replication in most cell culture systems. Some of the functions described for Vpr remain controversial. In particular, it remains unclear whether Vpr promotes or instead prevents proinflammatory and antiviral immune responses. In this report, we show that Vpr promotes the release of TNF, a proinflammatory cytokine associated with rapid disease progression. Using Vpr mutants or inhibiting selected cellular genes, we show that the cellular proteins DDB1 and TAK1 are involved in the release of TNF by HIV-infected cells. This report provides novel insights into how Vpr manipulates TNF production and helps clarify the role of Vpr in innate immune responses and inflammation.
| S-EPMC4645299 | biostudies-literature
Project description:Latency is the main obstacle towards an HIV cure, with cure strategies aiming to either elicit or prevent viral reactivation. While these strategies have shown promise, they have only succeeded in modulating latency in a fraction of the latent HIV reservoir, suggesting that the mechanisms controlling HIV latency are not completely understood, and that comprehensive latency modulation will require targeting of multiple latency maintenance pathways. We show here that the transcriptional co-activator and the central mediator of canonical Wnt signaling, β-catenin, inhibits HIV transcription in CD4+ T cells via TCF-4 LTR binding sites. Further, we show that inhibiting the β-catenin pathway reactivates HIV in a primary TCM cell model of HIV latency, primary cells from cART-controlled HIV donors, and in CD4+ latent cell lines. β-catenin inhibition or activation also enhanced or inhibited the activity of several classes of HIV latency reversing agents, respectively, in these models, with significant synergy of β-catenin and each LRA class tested. In sum, we identify β-catenin as a novel regulator of HIV latency in vitro and ex vivo, adding new therapeutic targets that may be combined for comprehensive HIV latency modulation in HIV cure efforts.
| S-EPMC8939789 | biostudies-literature
Project description:The interferon γ-inducible protein 16 (IFI16) is known as immune sensor of retroviral DNA intermediates. We show that IFI16 restricts HIV-1 independently of immune sensing by binding and inhibiting the host transcription factor Sp1 that drives viral gene expression. This antiretroviral activity and ability to bind Sp1 require the N-terminal pyrin domain and nuclear localization of IFI16, but not the HIN domains involved in DNA binding. Highly prevalent clade C HIV-1 strains are more resistant to IFI16 and less dependent on Sp1 than other HIV-1 subtypes. Furthermore, inhibition of Sp1 by IFI16 or pharmacologically by Mithramycin A suppresses reactivation of latent HIV-1 in CD4+ T cells. Finally, IFI16 also inhibits retrotransposition of LINE-1, known to engage Sp1, and murine IFI16 homologs restrict Friend retrovirus replication in mice. Thus, IFI16 restricts retroviruses and retrotransposons by interfering with Sp1-dependent gene expression, and evasion from this restriction may facilitate spread of HIV-1 subtype C.
| S-EPMC6681451 | biostudies-literature
Project description:DNA methylation of retroviral promoters and enhancers localized in the provirus 5' long terminal repeat (LTR) is considered to be a mechanism of transcriptional suppression that allows retroviruses to evade host immune responses and antiretroviral drugs. However, the role of DNA methylation in the control of HIV-1 latency has never been unambiguously demonstrated, in contrast to the apparent importance of transcriptional interference and chromatin structure, and has never been studied in HIV-1-infected patients. Here, we show in an in vitro model of reactivable latency and in a latent reservoir of HIV-1-infected patients that CpG methylation of the HIV-1 5' LTR is an additional epigenetic restriction mechanism, which controls resistance of latent HIV-1 to reactivation signals and thus determines the stability of the HIV-1 latency. CpG methylation acts as a late event during establishment of HIV-1 latency and is not required for the initial provirus silencing. Indeed, the latent reservoir of some aviremic patients contained high proportions of the non-methylated 5' LTR. The latency controlled solely by transcriptional interference and by chromatin-dependent mechanisms in the absence of significant promoter DNA methylation tends to be leaky and easily reactivable. In the latent reservoir of HIV-1-infected individuals without detectable plasma viremia, we found HIV-1 promoters and enhancers to be hypermethylated and resistant to reactivation, as opposed to the hypomethylated 5' LTR in viremic patients. However, even dense methylation of the HIV-1 5'LTR did not confer complete resistance to reactivation of latent HIV-1 with some histone deacetylase inhibitors, protein kinase C agonists, TNF-alpha, and their combinations with 5-aza-2deoxycytidine: the densely methylated HIV-1 promoter was most efficiently reactivated in virtual absence of T cell activation by suberoylanilide hydroxamic acid. Tight but incomplete control of HIV-1 latency by CpG methylation might have important implications for strategies aimed at eradicating HIV-1 infection.
| S-EPMC2722084 | biostudies-literature
Project description:The eradication of HIV-1 will likely require novel clinical approaches to purge the reservoir of latently infected cells from a patient. We hypothesize that this therapy should target a wide range of latent integration sites, act effectively against viral variants that have acquired mutations in their promoter regions, and function across multiple HIV-1 subtypes. By using primary CD4(+) and Jurkat cell-based in vitro HIV-1 latency models, we observe that single-agent latency reactivation therapy is ineffective against most HIV-1 subtypes. However, we demonstrate that the combination of two clinically promising drugs-namely, prostratin and suberoylanilide hydroxamic acid (SAHA)-overcomes the limitations of single-agent approaches and can act synergistically for many HIV-1 subtypes, including A, B, C, D, and F. Finally, by identifying the proviral integration position of latent Jurkat cell clones, we demonstrate that this drug combination does not significantly enhance the expression of endogenous genes nearest to the proviral integration site, indicating that its effects may be selective.
| S-EPMC2876650 | biostudies-literature
Project description:Reactivation of human immunodeficiency virus 1 (HIV-1) from latently infected T cells is a critical barrier to cure patients. It remains unknown whether reactivation of individual latent cells occurs stochastically in response to latency reversal agents (LRAs) or is a deterministic outcome of an underlying cell state. To characterize these single-cell responses, we leverage the classical Luria-Delbrück fluctuation test where single cells are isolated from a clonal population and exposed to LRAs after colony expansion. Data show considerable colony-to-colony fluctuations with the fraction of reactivating cells following a skewed distribution. Modeling systematic measurements of fluctuations over time uncovers a transient heritable memory that regulates HIV-1 reactivation, where single cells are in an LRA-responsive state for a few weeks before switching back to an irresponsive state. These results have enormous implications for designing therapies to purge the latent reservoir and further utilize fluctuation-based assays to uncover hidden transient cellular states underlying phenotypic heterogeneity.
| S-EPMC8050369 | biostudies-literature
Project description:Cells: ACH-2, and A3.01, were obtained through the NIH AIDS Research and Reference Reagent Program, Division of AIDS, NIAID, NIH. ACH-2, is a chronically infected cell line harboring HIV-1 LAV strain, while A3.01 is the corresponding parental uninfected cell line. Cells were grown in RPMI-1640 (Invitrogen, San Diego, CA) with 10% fetal bovine serum (FBS, Invitrogen), 5% penicillin-streptomycin (Invitrogen), and 2mM glutamine (Invitrogen). Cells were maintained at a concentration of 1x10e6 cells/ml in T-175 flasks. Cell concentrations and cell viability were monitored throughout the experiment at all time points studied. Cells were induced by addition of 20 ng/mL of phorbol myristyl acetate (PMA or TPA, Sigma, St Louis, MO) for one hour, after which the cells were washed with phosphate buffered saline (PBS). Cells were harvested by centrifugation at 1000 rpm for 10 minutes, at the following times after induction, 0.5, 3, 6, 8, 12, 18, 24, 48, 72, and 96 hour(s). HIV-infected and uninfected cells maintained and harvested in parallel with the PMA-treated cells, but not induced with PMA ( No PMA)were also harvested. Harvested cells were washed thrice with ice-cold PBS to remove media; cell pellets were snap frozen using ethanol-dry ice mixture and stored at (80°C for subsequent RNA extraction. Total RNA Extraction: Total RNA was extracted using RNEasy Midiprep Kits per manufacturer's protocol (Qiagen, Valencia, CA). RNA concentrations and purity were measured by spectrophotometry, RNA quality (absence of RNA degradation) was assessed by gel electrophoresis. RNA concentration was adjusted to the levels required for subsequent microarray experiment protocols by concentration in a SpeedVac (Savant Instruments, Holbrook, CA). RNA samples (6-7 µg/µL) were stored in 100 µL TE buffer at -80°C. Microarray Studies: Total RNA obtained from induced chronically infected and corresponding uninfected parental cells were used for microarray experiments. For each time point, RNA from the induced chronically infected ACH-2 cells and RNA from the corresponding induced, uninfected A3.01 cells were compared to minimize effects due to PMA induction. Microarrays were obtained from the National Cancer Institute Microarray Facility, Advanced Technology Center (Gaithersburg, MD). The microarrays (Hs. UniGem2) contained 10,368 cDNA spots on each glass slide. The cDNAs were selected for spotting on the slides based on their known or probable involvement in oncogenesis, signal transduction, apoptosis, immune function, inflammatory pathways, cellular transport, transcription, protein translation and other important cellular functions. A number of expressed sequence tags (ESTs) from unknown genes homologous to known genes and cDNAs encoding housekeeping genes were also included in these gene sets. For each time point, 50 µg of total RNA from PMA induced ACH-2 cells and 70 µg of total RNA from PMA induced A3.01 cells was labeled with Cy-3-dUTP and Cy-5-dUTP respectively. Higher amounts of RNA were used for Cy-5 labeling to minimize the disparities in dye incorporation. Each sample of RNA from PMA-induced, infected cells from a particular time point was compared with RNA from the corresponding PMA-induced, uninfected cells from the same time point for subsequent hybridization to the same array to ensure accurate comparisons and to eliminate inter-array variability. Following reverse transcription, the labeled cDNAs were then combined and purified using MicroCon YM-30 (Millipore, Bedford, MA) spin column filters, to remove any unincorporated nucleotides. 8-10 µg each of Cot-1 DNA, (Boehringer Mannheim, Indianapolis, IN), yeast tRNA (Sigma) and polyA (Amersham Biosciences) were added to the reaction mixture and heated at 100°C for 1 minute. Hybridization of the labeled cDNA to the microarray was carried out at 65°C overnight, followed by washes with 1X SSC, 0.2X SSC and 0.05X SSC respectively. The slides were dried by centrifugation at 1000 rpm for 3 minutes and then scanned as described below. Microarray Scanning and Data Analysis: The slides were scanned using an Axon GenePix 4000 scanner (Axon Instruments, Union City, CA). The photomultiplier tube values (PMT) were adjusted to obtain equivalent intensities at both wavelengths used, 635 nm and 532 nm for the Cy5 and Cy3 channels respectively. Image analysis was performed using GenePix analysis software (Axon Instruments) and data analysis was performed using the microArray Database (mAdb) system hosted by the Center for Information Technology and Center for Cancer Research at NIH (http://nciarray.nci.nih.gov/). Keywords = HIV Keywords = latency
2010-06-06 | E-GEOD-1441 | biostudies-arrayexpress
Project description:Latency allows HIV-1 to persist in long-lived cellular reservoirs, preventing virus eradication. We have previously shown that the heat shock protein 90 (Hsp90) is required for HIV-1 gene expression and mediates greater HIV-1 replication in conditions of hyperthermia. Here we report that specific inhibitors of Hsp90 such as 17-(N-allylamino)-17-demethoxygeldanamycin and AUY922 prevent HIV-1 reactivation in CD4+ T cells. A single modification at position 19 in the Hsp90 inhibitors abolished this activity, supporting the specificity of the target. We tested the impact of Hsp90 on known pathways involved in HIV-1 reactivation from latency; they include protein kinase Cs(PKCs), mitogen activated protein kinase/extracellular signal regulated kinase/positive transcriptional elongation factor-b and NF-?B. We found that Hsp90 was required downstream of PKCs and was not required for mitogen activated protein kinase activation. Inhibition of Hsp90 reduced degradation of IkB? and blocked nuclear translocation of transcription factor p65/p50, suppressing the NF-?B pathway. Coimmunoprecipitation experiments showed that Hsp90 interacts with inhibitor of nuclear factor kappa-B kinase (IKK) together with cochaperone Cdc37, which is critical for the activity of several kinases. Targeting of Hsp90 by AUY922 dissociated Cdc37 from the complex. Therefore, Hsp90 controls HIV-1 reactivation from latency by keeping the IKK complex functional and thus connects T-cell activation with HIV-1 replication. AUY922 is in phase II clinical trial and, in combination with a PKC-? inhibitor in phase II clinical trial, almost completely suppressed HIV-1 reactivation at 15 nM with no cytotoxicity. Selective targeting of the Hsp90/Cdc37 interaction may provide a powerful approach to suppress HIV-1 reactivation from latency.
| S-EPMC3992654 | biostudies-literature
Project description:BackgroundCurrent antiretroviral therapy is effective in controlling HIV-1 infection. However, cessation of therapy is associated with rapid return of viremia from the viral reservoir. Eradicating the HIV-1 reservoir has proven difficult with the limited success of latency reactivation strategies and reflects the complexity of HIV-1 latency. Consequently, there is a growing need for alternate strategies. Here we explore a "block and lock" approach for enforcing latency to render the provirus unable to restart transcription despite exposure to reactivation stimuli. Reactivation of transcription from latent HIV-1 proviruses can be epigenetically blocked using promoter-targeted shRNAs to prevent productive infection. We aimed to determine if independent and combined expression of shRNAs, PromA and 143, induce a repressive epigenetic profile that is sufficiently stable to protect latently infected cells from HIV-1 reactivation when treated with a range of latency reversing agents (LRAs).ResultsJ-Lat 9.2 cells, a model of HIV-1 latency, expressing shRNAs PromA, 143, PromA/143 or controls were treated with LRAs to evaluate protection from HIV-1 reactivation as determined by levels of GFP expression. Cells expressing shRNA PromA, 143, or both, showed robust resistance to viral reactivation by: TNF, SAHA, SAHA/TNF, Bryostatin/TNF, DZNep, and Chaetocin. Given the physiological importance of TNF, HIV-1 reactivation was induced by TNF (5 ng/mL) and ChIP assays were performed to detect changes in expression of epigenetic markers within chromatin in both sorted GFP- and GFP+ cell populations, harboring latent or reactivated proviruses, respectively. Ordinary two-way ANOVA analysis used to identify interactions between shRNAs and chromatin marks associated with repressive or active chromatin in the integrated provirus revealed significant changes in the levels of H3K27me3, AGO1 and HDAC1 in the LTR, which correlated with the extent of reduced proviral reactivation. The cell line co-expressing shPromA and sh143 consistently showed the least reactivation and greatest enrichment of chromatin compaction indicators.ConclusionThe active maintenance of epigenetic silencing by shRNAs acting on the HIV-1 LTR impedes HIV-1 reactivation from latency. Our "block and lock" approach constitutes a novel way of enforcing HIV-1 "super latency" through a closed chromatin architecture that renders the virus resistant to a range of latency reversing agents.
| S-EPMC6172763 | biostudies-literature
Project description:Interstitial pneumonia is a major clinical manifestation of primary or recurrent cytomegalovirus (CMV) infection in immunocompromised recipients of a bone marrow transplant. In a murine model, lungs were identified as a prominent site of CMV latency and recurrence. Pulmonary latency of murine CMV is characterized by high viral genome burden and a low incidence of variegated immediate-early (IE) gene expression, reflecting a sporadic activity of the major IE promoters (MIEPs) and enhancer. The enhancer-flanking promoters MIEP1/3 and MIEP2 are switched on and off during latency in a ratio of approximately 2:1. MIEP1/3 latency-associated activity generates the IE1 transcript of the ie1/3 transcription unit but not the alternative splicing product IE3 that encodes the essential transactivator of early gene expression. Splicing thus appeared to be an important checkpoint for maintenance of latency. In accordance with previous work of others, we show here that signaling by the proinflammatory cytokine tumor necrosis factor alpha (TNF-alpha) activates IE1/3 transcription in vivo. As an addition to current knowledge, Poisson distribution analysis revealed an increased incidence of IE1/3 transcriptional events as well as a higher amount of transcripts per event. Notably, TNF-alpha promoted the splicing to IE3 transcripts, but transcription did not proceed to the M55/gB early gene. Moreover, the activated transcriptional state induced by TNF-alpha did not predispose latently infected mice to a higher incidence of virus recurrence after hematoablative treatment. In conclusion, TNF-alpha is an important inductor of IE gene transcriptional reactivation, whereas early genes downstream in the viral replicative cycle appear to be the rate-limiting checkpoint(s) for virus recurrence.
| S-EPMC538715 | biostudies-literature