Project description:Human immunodeficiency virus (HIV) infection is a chronic condition, where viral DNA integrates into the genome. The fate of the provirus determines the infection course. Latently infected cells form a persistent, heterogeneous reservoir. The reservoir that reinstates an active infection comprises cells with intact provirus that can be reactivated. We confirmed that latent cells from patients exhibited active transcription throughout the provirus. To find transcriptional determinants, we characterized the establishment and maintenance of latency during proviral chromatin maturation in primary CD4+ T-cells for four months after HIV infection. As heterochromatin (marked with H3K9me3 or H3K27me3) gradually stabilized, the provirus became less accessible and lost activation potential. In a subset of infected cells, active marks (i.e., H3K27ac) remained detectable, even after prolonged proviral silencing. After T-cell activation, the proviral activation occurred uniquely in cells with H3K27ac-marked proviruses. Our observations suggested that, after transient proviral activation, cells were actively returned to latency.
Project description:Resting CD4+ T cells are infected by HIV-1 in vivo, however are refractory to cell-free HIV-1 infection in vitro. We show that they are efficiently infected by cell-to-cell spread. To allow resting T cell infection, uninfected resting target cells were co-cultured with infected donor T cells. Cells were infected with HIV-1 WT, dVpr or left mock treated and cultures with or without IL7. After 72h of co-culture, resting target cells were recovered by flow cytometry sorting and total RNA was extracted. RNASequencing revealed global transcriptomic reprogramming of resting memory T cells by HIV-1 Vpr.
Project description:BACKGROUND: Combination antiretroviral therapy (cART) is able to control HIV-1 viral replication, however long-lived latent infection in resting memory CD4+ T-cells persist. The mechanisms for establishment and maintenance of latent infection in resting memory CD4+ T-cells remain unclear. Previously we have shown that HIV-1 infection of resting CD4+ T-cells co-cultured with CD11c+ myeloid dendritic cells (mDC) produced a population of non-proliferating T-cells with latent infection. Here we asked whether different antigen presenting cells (APC), including subpopulations of DC and monocytes, were able to induce post-integration latent infection in resting CD4+ T-cells, and examined potential cell interactions that may be involved using RNA-seq. RESULTS: mDC (CD1c+), SLAN+ DC and CD14+ monocytes were most efficient in stimulating proliferation of CD4+ T-cells during syngeneic culture and in generating post-integration latent infection in non-proliferating CD4+ T-cells following HIV-1 infection of APC-T-cell co-cultures. In comparison, plasmacytoid DC (pDC) and B-cells did not induce latent infection in APC-T-cell co-cultures. We compared the RNA expression profiles of APC subpopulations that could and could not induce latency in non-proliferating CD4+ T-cells. Gene expression analysis, comparing the mDC, SLAN+ DC and CD14+ monocyte subpopulations to pDC identified 53 upregulated genes that encode proteins expressed on the plasma membrane that could signal to CD4+ T-cells via cell-cell interactions (32 genes), immune checkpoints (IC) (5 genes), T-cell activation (9 genes), regulation of apoptosis (5 genes), antigen presentation (1 gene) and through unknown ligands (1 gene). CONCLUSIONS: APC subpopulations from the myeloid lineage, specifically mDC subpopulations and CD14+ monocytes, were able to efficiently induce post-integration HIV-1 latency in non-proliferating CD4+ T-cells in vitro. Inhibition of key pathways involved in mDC-T-cell interactions and HIV-1 latency may provide novel targets to eliminate HIV latency. mRNA profiles of sorted, pure antigen presenting cells including, CD1c+ myleoid dendirtic cells (mDC), SLAN+ mDC, CD14+ monocytes and plasmacytoid DC (pDC), were generated using next generation sequencing in triplicate, using Illumina Illumina Hiseq 2000.
Project description:BACKGROUND: Combination antiretroviral therapy (cART) is able to control HIV-1 viral replication, however long-lived latent infection in resting memory CD4+ T-cells persist. The mechanisms for establishment and maintenance of latent infection in resting memory CD4+ T-cells remain unclear. Previously we have shown that HIV-1 infection of resting CD4+ T-cells co-cultured with CD11c+ myeloid dendritic cells (mDC) produced a population of non-proliferating T-cells with latent infection. Here we asked whether different antigen presenting cells (APC), including subpopulations of DC and monocytes, were able to induce post-integration latent infection in resting CD4+ T-cells, and examined potential cell interactions that may be involved using RNA-seq. RESULTS: mDC (CD1c+), SLAN+ DC and CD14+ monocytes were most efficient in stimulating proliferation of CD4+ T-cells during syngeneic culture and in generating post-integration latent infection in non-proliferating CD4+ T-cells following HIV-1 infection of APC-T-cell co-cultures. In comparison, plasmacytoid DC (pDC) and B-cells did not induce latent infection in APC-T-cell co-cultures. We compared the RNA expression profiles of APC subpopulations that could and could not induce latency in non-proliferating CD4+ T-cells. Gene expression analysis, comparing the mDC, SLAN+ DC and CD14+ monocyte subpopulations to pDC identified 53 upregulated genes that encode proteins expressed on the plasma membrane that could signal to CD4+ T-cells via cell-cell interactions (32 genes), immune checkpoints (IC) (5 genes), T-cell activation (9 genes), regulation of apoptosis (5 genes), antigen presentation (1 gene) and through unknown ligands (1 gene). CONCLUSIONS: APC subpopulations from the myeloid lineage, specifically mDC subpopulations and CD14+ monocytes, were able to efficiently induce post-integration HIV-1 latency in non-proliferating CD4+ T-cells in vitro. Inhibition of key pathways involved in mDC-T-cell interactions and HIV-1 latency may provide novel targets to eliminate HIV latency.
Project description:Latently infected resting CD4+ T cells are a major barrier to HIV cure. Understanding how latency is established, maintained and reversed is critical to identifying novel strategies to eliminate latently infected cells. We demonstrate here that co-culture of resting CD4+ T cells and syngeneic myeloid dendritic cells (mDC) can dramatically increase the frequency of HIV DNA integration and latent HIV infection in non-proliferating memory, but not naïve, CD4+ T cells. Gene expression in non-proliferating CD4+ T cells, enriched for latent infection, showed significant changes in the expression of genes involved in cellular activation and interferon regulated pathways, including the down-regulation of genes controlling both NF-κB and cell cycle. We conclude that mDC play a key role in the establishment of HIV latency in resting memory CD4+ T cells, which is predominantly mediated through signalling during DC-T cell contact. Resting (CD69-CD25-HLA-DR-) CD4+ T cells were enriched from the blood of 4 normal donors by magnetic bead depletion and labelled with the proliferation dye SNARF. SNARFhiEGFP- CD4+ T cells cultured with (+DC) or without syngeneic bulk DC (lin-HLA-DR+), in the presence (HIV T) or absence (Mock T) of HIV, were sorted 5 days following infection with NL(AD8)-nef/EGFP (MOI 5).Culture media was supplemented with 10ng/mL of IL-7. The gene expression profile of the 4 cell populations: 1. HIV T (+DC); 2. Mock T (+DC); 3. HIV T; and 4. Mock T, was determined.
Project description:HIV latency is a major obstacle to curing infection. Current strategies to eradicate HIV aim at increasing transcription of the latent provirus. In the present study we observed that latently infected CD4+ T cells from HIV-infected individuals failed to produce viral particles upon ex vivo exposure to SAHA (vorinostat), despite effective inhibition of histone deacetylases. To identify steps that were not susceptible to the action of SAHA or other latency reverting agents, we used a primary CD4+ T cell model, joint host and viral RNA sequencing, and a viral-encoded reporter. This model served to investigate the characteristics of latently infected cells, the dynamics of HIV latency, and the process of reactivation induced by various stimuli. During latency, we observed persistence of viral transcripts but only limited viral translation. Similarly, the reactivating agents SAHA and disulfiram successfully increased viral transcription, but failed to effectively enhance viral translation, mirroring the ex vivo data. This study highlights the importance of post-transcriptional blocks as one mechanism leading to HIV latency that needs to be relieved in order to purge the viral reservoir.
Project description:Latently infected resting CD4+ T cells are a major barrier to HIV cure. Understanding how latency is established, maintained and reversed is critical to identifying novel strategies to eliminate latently infected cells. We demonstrate here that co-culture of resting CD4+ T cells and syngeneic myeloid dendritic cells (mDC) can dramatically increase the frequency of HIV DNA integration and latent HIV infection in non-proliferating memory, but not naïve, CD4+ T cells. Gene expression in non-proliferating CD4+ T cells, enriched for latent infection, showed significant changes in the expression of genes involved in cellular activation and interferon regulated pathways, including the down-regulation of genes controlling both NF-κB and cell cycle. We conclude that mDC play a key role in the establishment of HIV latency in resting memory CD4+ T cells, which is predominantly mediated through signalling during DC-T cell contact.
Project description:Latent HIV reservoirs are extremely stable which pose a tremendous challenge to eradicate HIV. Here, we show that HIV explores the integrated stress response (ISR) signaling to establish its quiescent infection, refractory to the clearance for its persistence. HA15, a recently characterized specific ISR agonist, activates ATF4/CHOP signaling to not only disrupt HIV latency but also reduce HIV+ cells in the primary CD4+ T cell model of HIV latency without the induction of cell death in the HIV negative primary CD4+ T cells and the impact of viability in resting CD4+ T cells isolated from people living with HIV (PLWH). Mechanistically, the reduction of HIV+ cells by ISR/ATF4 activation is associated with the enhancement of cellular apoptosis. However, this mainly occurs in the HIV translation negative CD4+ T cells. In fact, ISR/ATF4 activation-induced cell death largely occurs in HIV transcription active (HIV gag-pol) CD4+ T cells. This is involved in HIV RNA-induced innate immune IFIT signaling. During the acute SIV infection in the rhesus macaques, the induction of ATF4 is associated with decrease of SIV reservoir in the intestine in vivo. When further tested in the resting CD4+ T cells isolated from PLWH on ART, the induction of ISR/ATF4 signaling by HA15 reduced HIV DNA reservoir. These findings support that inactivation of ISR/ATF4 signaling is associated with the maintenance of the stable and quiescent HIV reservoirs while enforced ISR/ATF4 signaling reduces translation quiescent HIV reservoirs in CD4+ T cells.
Project description:Because HIV provirus in many cells during latency is not entirely silent, it became possible to use single-cell RNA sequencing (scRNA-seq) to determine gene expression patterns in a subset of latently infected cells. In this study, we aimed to identify molecular signatures, or biomarkers, of latency established in different conditions. We have used two in vitro models of HIV latency. The first model involved infection, activation of CD4+ T cells using anti-CD3/anti-CD28 antibodies and allowing the cells to return to quiescence (the 14-day model). The second model involved direct infection of the resting CD4+ T cells via co-culture with autologous productively infected cells to allow cell-to-cell virus transmission (the 10-day model). Furthermore, we utilized an isogenic pair of CXCR4- and CCR5-tropic viruses for direct infection of resting cells. Finally, CD4+ T cells from people with HIV were also profiled. We show common and unique molecular signatures of latency established in different conditions; a subset of genes identified in vitro was validated using cells from people with HIV.