trichostatin-a and HIV-Infections

Despite the advances in Human Immunodeficiency Virus (HIV) treatment, the cure for all HIV patients still poses a major challenge, which needs to be surpassed in the coming years. Among the strategies pursuing this aim, the 'kick-and-kill' approach, which involves the reactivation and elimination of a latent HIV reservoir that resides in some CD4

Topics: Anti-HIV Agents; CD4-Positive T-Lymphocytes; Histone Deacetylase Inhibitors; HIV Infections; HIV-1; Humans; Molecular Structure; Virus Latency

People living with HIV (PLWH) have to take an antiretroviral therapy (ART) for life and show noncommunicable illnesses such as chronic inflammation, immune activation, and multiorgan dysregulation. Recent studies suggest that long-term use of ART induces comorbid conditions and is one of the leading causes of heart failure in PLWH. However, the molecular mechanism of antiretroviral drugs (ARVs) induced heart failure is unclear. To determine the mechanism of ARVs induced cardiac dysfunction, we performed global transcriptomic profiling of ARVs treated neonatal rat ventricular cardiomyocytes in culture. Differentially expressed genes were identified by RNA-sequencing. Our data show that ARVs treatment causes upregulation of several biological functions associated with cardiotoxicity, hypertrophy, and heart failure. Global gene expression data were validated in cardiac tissue isolated from HIV patients having a history of ART. Interestingly, we found that homeodomain-only protein homeobox (HOPX) expression was significantly increased in cardiomyocytes treated with ARVs and in the heart tissue of HIV patients. Furthermore, we found that HOPX plays a crucial role in ARVs mediated cellular hypertrophy. Mechanistically, we found that HOPX plays a critical role in epigenetic regulation, through deacetylation of histone, while the HDAC inhibitor, Trichostatin A, can restore the acetylation level of histone 3 in the presence of ARVs.

Topics: Acetylation; Animals; Anti-Retroviral Agents; Cardiomegaly; Disease Models, Animal; Epigenesis, Genetic; Gene Expression Regulation; Heart Failure; Histone Deacetylase Inhibitors; HIV; HIV Infections; Homeodomain Proteins; Humans; Hydroxamic Acids; Myocytes, Cardiac; Rats; RNA-Seq; Transcriptome; Tumor Suppressor Proteins

The abundance of long noncoding RNAs (lncRNAs) and their wide range of functional roles in human cells are fast becoming realized. Importantly, lncRNAs have been identified as epigenetic modulators and consequently play a pivotal role in the regulation of gene expression. A human immunodeficiency virus-encoded antisense RNA transcript has recently been reported and we sought to characterize this RNA and determine its potential role in viral transcription regulation. The intrinsic properties of this human immunodeficiency virus-expressed lncRNA were characterized and the data presented here suggest that it functions as an epigenetic brake to modulate viral transcription. Suppression of this long antisense transcript with small single-stranded antisense RNAs resulted in the activation of viral gene expression. This lncRNA was found to localize to the 5' long-term repeats (LTR) and to usurp components of endogenous cellular pathways that are involved in lncRNA directed epigenetic gene silencing. Collectively, we find that this viral expressed antisense lncRNA is involved in modulating human immunodeficiency virus gene expression and that this regulatory effect is due to an alteration in the epigenetic landscape at the viral promoter.

Topics: Azacitidine; Epigenesis, Genetic; Gene Expression Regulation, Viral; HEK293 Cells; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Jurkat Cells; Promoter Regions, Genetic; RNA, Antisense; RNA, Long Noncoding; RNA, Messenger; RNA, Viral

Histone deacetylase inhibitors (HDACi) can induce human immunodeficiency virus (HIV) transcription from the HIV long terminal repeat (LTR). However, ex vivo and in vivo responses to HDACi are variable and the activity of HDACi in cells other than T-cells have not been well characterised. Here, we developed a novel assay to determine the activity of HDACi on patient-derived HIV LTRs in different cell types. HIV LTRs from integrated virus were amplified using triple-nested Alu-PCR from total memory CD4+ T-cells (CD45RO+) isolated from HIV-infected patients prior to and following suppressive antiretroviral therapy. NL4-3 or patient-derived HIV LTRs were cloned into the chromatin forming episomal vector pCEP4, and the effect of HDACi investigated in the astrocyte and epithelial cell lines SVG and HeLa, respectively. There were no significant differences in the sequence of the HIV LTRs isolated from CD4+ T-cells prior to and after 18 months of combination antiretroviral therapy (cART). We found that in both cell lines, the HDACi panobinostat, trichostatin A, vorinostat and entinostat activated patient-derived HIV LTRs to similar levels seen with NL4-3 and all patient derived isolates had similar sensitivity to maximum HDACi stimulation. We observed a marked difference in the maximum fold induction of luciferase by HDACi in HeLa and SVG, suggesting that the effect of HDACi may be influenced by the cellular environment. Finally, we observed significant synergy in activation of the LTR with vorinostat and the viral protein Tat. Together, our results suggest that the LTR sequence of integrated virus is not a major determinant of a functional response to an HDACi.

Topics: Adult; Aged; Anti-HIV Agents; Benzamides; Cell Line; HeLa Cells; Histone Deacetylase Inhibitors; HIV Infections; HIV Long Terminal Repeat; Humans; Hydroxamic Acids; Indoles; Observational Studies as Topic; Panobinostat; Phylogeny; Pyridines; T-Lymphocytes; tat Gene Products, Human Immunodeficiency Virus; Vorinostat

HIV-1 latency represents a major problem in the eradication of HIV-1 in infected individuals treated with highly active anti-retroviral therapy. Histone deacetylase (HDAC) inhibits HIV-1 gene expression and virus production and may contribute to quiescence of HIV-1 within resting CD4+ T cells. Here, we evaluated the effect of Oxamflatin, a class I HDAC inhibitor, on the epigenetic change at HIV-1 long terminal repeat (LTR) and the induction of the latent viruses in the latency Jurkat T cell line. Flow cytometry assay showed that Oxamflatin activate HIV-1 gene expression in these latently infected cells by 2-17 fold than background levels. Chromatin immunoprecipitation (ChIP) assays further revealed that Oxamflatin increase the acetylation level of histone H3 and histone H4 at the nucleosome 1(nuc-1) site of the HIV-1 LTR compared to mock treatment. We also found that Oxamflatin had a synergization with prostratin, or 5-azacytidine or tumor necrosis factor-α to activate the HIV-1 promoter. Taken together, our results suggest that the histone acetylation plays an important role in regulating HIV-1 LTR gene expression, and Oxamflatin has potential as drug candidates as antilatency therapies.

Topics: Acetylation; Cell Death; Cell Survival; Chromatin Immunoprecipitation; Dose-Response Relationship, Drug; Drug Synergism; HEK293 Cells; Histone Deacetylase Inhibitors; Histones; HIV Infections; HIV Long Terminal Repeat; HIV-1; Humans; Hydroxamic Acids; Jurkat Cells; Promoter Regions, Genetic; Protein Processing, Post-Translational; Time Factors; Transcription, Genetic; Virus Latency

Recently, there is considerable interest in the field of anti-HIV therapy to identify and develop chromatin-modifying histone deacetylase (HDAC) inhibitors that can effectively reactivate latent HIV in patients. The hope is that this would help eliminate cells harboring latent HIV and achieve an eventual cure of the virus. However, how effectively these drugs can stimulate latent HIVs in quiescent primary CD4 T cells, despite their relevant potencies demonstrated in cell line models of HIV latency, is not clear. Here, we show that the HDAC inhibitors valproic acid (VPA) and trichostatin A (TSA) are unable to reactivate HIV in latently infected primary CD4 T cells generated in the H80 co-culture system. This raises a concern that the drugs inhibiting HDAC function alone might not be sufficient for stimulating latent HIV in resting CD4 T cells in patients and not achieve any anticipated reduction in the pool of latent reservoirs.

Topics: CD4-Positive T-Lymphocytes; Cells, Cultured; Coculture Techniques; Histone Deacetylase Inhibitors; HIV Infections; Humans; Hydroxamic Acids; Valproic Acid; Virus Latency

Cells latently infected with HIV represent a currently insurmountable barrier to viral eradication in infected patients. Using the J-Lat human T-cell model of HIV latency, we have investigated the role of host factor binding to the kappaB enhancer elements of the HIV long terminal repeat (LTR) in the maintenance of viral latency. We show that NF-kappaB p50-HDAC1 complexes constitutively bind the latent HIV LTR and induce histone deacetylation and repressive changes in chromatin structure of the HIV LTR, changes that impair recruitment of RNA polymerase II and transcriptional initiation. Knockdown of p50 expression with specific small hairpin RNAs reduces HDAC1 binding to the latent HIV LTR and induces RNA polymerase II recruitment. Similarly, inhibition of histone deacetylase (HDAC) activity with trichostatin A promotes binding of RNA polymerase II to the latent HIV LTR. This bound polymerase complex, however, remains non-processive, generating only short viral transcripts. Synthesis of full-length viral transcripts can be rescued under these conditions by expression of Tat. The combination of HDAC inhibitors and Tat merits consideration as a new strategy for purging latent HIV proviruses from their cellular reservoirs.

Topics: Cells, Cultured; Chromatin; Enhancer Elements, Genetic; Gene Products, tat; Histone Deacetylase 1; Histone Deacetylase Inhibitors; Histone Deacetylases; Histones; HIV Infections; HIV Long Terminal Repeat; HIV-1; Humans; Hydroxamic Acids; NF-kappa B p50 Subunit; Promoter Regions, Genetic; RNA Polymerase II; T-Lymphocytes; tat Gene Products, Human Immunodeficiency Virus; Transcription, Genetic; Virus Latency

Efficient human immunodeficiency virus (HIV)-1 infection depends on multiple interactions between the viral gp41/gp120 envelope (Env) proteins and cell surface receptors. However, cytoskeleton-associated proteins that modify membrane dynamics may also regulate the formation of the HIV-mediated fusion pore and hence viral infection. Because the effects of HDAC6-tubulin deacetylase on cortical alpha-tubulin regulate cell migration and immune synapse organization, we explored the possible role of HDAC6 in HIV-1-envelope-mediated cell fusion and infection. The binding of the gp120 protein to CD4+-permissive cells increased the level of acetylated alpha-tubulin in a CD4-dependent manner. Furthermore, overexpression of active HDAC6 inhibited the acetylation of alpha-tubulin, and remarkably, prevented HIV-1 envelope-dependent cell fusion and infection without affecting the expression and codistribution of HIV-1 receptors. In contrast, knockdown of HDAC6 expression or inhibition of its tubulin deacetylase activity strongly enhanced HIV-1 infection and syncytia formation. These results demonstrate that HDAC6 plays a significant role in regulating HIV-1 infection and Env-mediated syncytia formation.

Topics: Acetylation; Aminobenzoates; CD4-Positive T-Lymphocytes; Cell Fusion; Cell Line, Tumor; Gene Silencing; HeLa Cells; Histone Deacetylase 6; Histone Deacetylases; HIV Envelope Protein gp120; HIV Infections; HIV-1; Humans; Hydroxamic Acids; Jurkat Cells; Pyrazines; RNA, Small Nuclear; Transfection; Tubulin

The transcription factor NF-kappaB plays a central role in the human immunodeficiency virus type 1 (HIV-1) activation pathway. HIV-1 transcription is also regulated by protein acetylation, since treatment with deacetylase inhibitors such as trichostatin A (TSA) or sodium butyrate (NaBut) markedly induces HIV-1 transcriptional activity of the long terminal repeat (LTR) promoter. Here, we demonstrate that TSA (NaBut) synergized with both ectopically expressed p50/p65 and tumor necrosis factor alpha/SF2 (TNF)-induced NF-kappaB to activate the LTR. This was confirmed for LTRs from subtypes A through G of the HIV-1 major group, with a positive correlation between the number of kappaB sites present in the LTRs and the amplitude of the TNF-TSA synergism. Mechanistically, TSA (NaBut) delayed the cytoplasmic recovery of the inhibitory protein IkappaBalpha. This coincided with a prolonged intranuclear presence and DNA binding activity of NF-kappaB. The physiological relevance of the TNF-TSA (NaBut) synergism was shown on HIV-1 replication in both acutely and latently HIV-infected cell lines. Therefore, our results open new therapeutic strategies aimed at decreasing or eliminating the pool of latently HIV-infected reservoirs by forcing viral expression.

Topics: Acetylation; Butyrates; Cell Line; Cell Nucleus; Cytoplasm; DNA; DNA-Binding Proteins; Gene Expression Regulation, Viral; Histone Deacetylase Inhibitors; HIV Infections; HIV Long Terminal Repeat; HIV-1; Humans; Hydroxamic Acids; I-kappa B Proteins; Mutagenesis; NF-kappa B; NF-kappa B p50 Subunit; NF-KappaB Inhibitor alpha; Transcription Factor RelA; Transcriptional Activation; Tumor Necrosis Factor-alpha; U937 Cells; Virus Latency; Virus Replication