Transcriptional reprogramming of human CD4 T cells transitioning from active to memory state
ABSTRACT: The latent reservoir for HIV-1 in resting memory CD4+ T cells is the major barrier to curing HIV-1 infection. Studies of HIV-1 latency have focused on regulation of viral gene expression in cells in which latent infection is established. However, it remains unclear how infection initially becomes latent. Here we described a unique set of properties of CD4+ T cells undergoing effector-to-memory transition including temporary up-regulation of CCR5 expression and rapid down-regulation of cellular gene transcription. These cells allowed completion of steps in the HIV-1 life cycle through integration, but suppressed HIV-1 gene transcription, thus allowing the establishment of latency. CD4+ T cells in this stage were substantially more permissive for HIV-1 latent infection than other CD4+ T cells. Establishment of latent HIV-1 infection in CD4+ T could be inhibited by viral-specific CD8+ T cells, a result with implications for elimination of latent HIV-1 infection by T cell-based vaccines. Overall design: CD4+ T cells from three donors at 5 different treatment time points.
INSTRUMENT(S): [PrimeView] Affymetrix Human Gene Expression Array
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. Overall design: Establishment and maintenance of HIV latency+ reactivation with different agents. RNAseq was performed for both HIV infected and mock infected cells at: Week 0,2,4,6,8 and 10 of latency and at 8, 24 and/or 72 hours post reactivation with vorinostat (SAHA), disulfiram (disu), azacytidine (aza), interleukin-7 (IL-7), anti-CD3/anti-CD28 (antiCD3) or DMSO).
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: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:Aguilera 2014 - HIV latency. Interaction
between HIV proteins and immune response
This model is described in the article:
Studying HIV latency by
modeling the interaction between HIV proteins and the innate
J. Theor. Biol. 2014 Nov; 360:
HIV infection leads to two cell fates, the viral productive
state or viral latency (a reversible non-productive state). HIV
latency is relevant because infected active CD4+ T-lymphocytes
can reach a resting memory state in which the provirus remains
silent for long periods of time. Despite experimental and
theoretical efforts, the causal molecular mechanisms
responsible for HIV latency are only partially understood.
Studies have determined that HIV latency is influenced by the
innate immune response carried out by cell restriction factors
that inhibit the postintegration steps in the virus replication
cycle. In this study, we present a mathematical study that
combines deterministic and stochastic approaches to analyze the
interactions between HIV proteins and the innate immune
response. Using wide ranges of parameter values, we observed
the following: (1) a phenomenological description of the viral
productive and latent cell phenotypes is obtained by bistable
and bimodal dynamics, (2) biochemical noise reduces the
probability that an infected cell adopts the latent state, (3)
the effects of the innate immune response enhance the HIV
latency state, (4) the conditions of the cell before infection
affect the latent phenotype, i.e., the existing expression of
cell restriction factors propitiates HIV latency, and existing
expression of HIV proteins reduces HIV latency.
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Project description:Suppressive HAART does not eradicate HIV-1 and viral DNA persists as a stably integrated form in the absence of viral particle production. As a consequence, latent reservoirs are refractory to antiretroviral drugs and invisible to immune surveillance. The largest latent reservoir consists of resting memory CD4+ T cells. These cells can resume viral infection when activated through antigen recognition, causing bursts of viremia (blips). Current therapies targeting latent HIV-1 have focused primarily on the “shock and kill” approach, which employs “anti-latency” drugs – most notably histone deacetylase (HDAC) inhibitors – to reactivate and flush latent provirus from its cellular reservoirs in the absence of global T cell activation. This approach is predicated on the notions that viral reactivation will lead to the demise of the infected cell, and that HAART will prevent spreading of the infection. On the contrary, recent evidence indicates that latently infected CD4+ T cells of HIV-1 patients on HAART survive in vitro viral reactivation with the HDAC inhibitor, SAHA, even when co-cultured with autologous CD8+ cytotoxic T lymphocytes (CTL). Moreover, it remains to be addressed the impact of anti-latency drugs on viral reservoirs undergoing low-level ongoing replication, inherently more resistant to the cytopathic effects of HIV-1 and residing in anatomical sites hard to reach for some antiretroviral drugs (e.g. macrophages). As a consequence, there is a need to develop alternative therapeutic approaches aimed at eliminating or decreasing the latent reservoir. Progress in that direction has been hindered by the lack of biomarkers uniquely or differentially expressed on latently infected compared to their uninfected counterparts. To gain insight into the cellular mechanisms that take place in the context of latency, and with the goal of identifying distinctive markers that distinguish latently infected CD4+ T cells, we have used an in vitro model developed in our laboratory to study the expression profile of latently infected CD4+ T cells by microarray analysis. We have used a culture system, previously established in our laboratory, to generate and isolate quiescent latently infected CD4+ T cells in vitro. In this in vitro HIV-1 latency model, CD4+ T cells are activated, infected with full length, replication competent HIV-1, and then returned to quiescence in the presence of IL-7, yielding a culture of quiescent latently infected and uninfected cells. We showed that HIV-1 p24gag expressed during viral replication persists in the cytoplasm of latently infected cells for several days before being degraded. Therefore, we exploited the presence of cytoplasmic p24gag to sort latently infected from uninfected cells by FACS from the same initial cell culture. Total RNA was isolated from sorted latently infected and uninfected cells generated from CD4+ T cells of four different donors. Paired RNA samples from infected and uninfected cells were labeled with Cy3 and Cy5 to allow dual-color competitive hybridization. Moreover, to control for the dye bias in our experiments, we implemented a dye swap protocol (reciprocal labeling) for paired RNA samples from 2 donors. Samples were analyzed by dual-color competitive hybridization on the Agilent whole human genome microarrays (41,000 unique probes). This is the first comparative genomic profiling of primary latently infected resting memory CD4+ T cells versus their uninfected counterparts sorted from the same culture. Microarray analyses performed in this study revealed profound differences between latently infected and uninfected cells. Of relevance are genes involved, not only in previously described pathways related with transcriptional and post-transcriptional regulation, but affecting proliferation, survival, cell cycle progression and cell metabolism. This could explain why latently infected cells have been resistant to reactivation with current anti-latency approaches. Thus, targeting of more downstream steps, such as the ones identified in this study, may be able to enhance viral flushing from refractory latent reservoirs. In addition, we identified a panel of surface makers differentially expressed in latently infected cells, which seem worth investigating for their potential use as biomarkers. Indeed, they might allow the enrichment of this latent reservoir for molecular in depth studies, for monitoring the size of the latent reservoir in the clinical setting, as well as for the development of new therapeutic strategies aimed at eradicating this reservoir.
Project description:Despite effective treatment, HIV can persist in latent reservoirs, which represent a major obstacle towards HIV eradication. Targeting and reactivating latent cells is challenging due to the heterogeneous nature of HIV infected cells. Here, we used a primary model of HIV latency and single-cell RNA sequencing to characterize transcriptional heterogeneity during HIV latency and reactivation. Our analysis identified transcriptional programs leading to successful reactivation of HIV expression. We further validated our results using primary CD4+ T cells isolated from HIV+ individuals. Overall design: Human primary CD4+ T-cells were infected, cultured, and maintained in a resting, latent phenotype in order to generate a primary model of HIV latency. Latently infected cells were either left untreated, or exposed to SAHA or TCR stimulation, followed by single-cell isolation and single-cell RNA-seq (scRNA-Seq) analysis. Bulk RNA-Seq experiments were also performed as control. To validate the observed cellular heterogeneity in the primary model of HIV latency, we used primary CD4+ T cells isolated from HIV+ individuals. As for the primary HIV latency model, resting cells from HIV+ individuals were either not treated or TCR-treated before single cell isolation and single-cell RNA-Seq.
Project description:Latent HIV-1 infection represents a barrier to virus eradication as latent HIV-1 is impervious to the effects of antiretroviral drugs and can avoid detection by the host immune system. Strategies to clear latent HIV-1 infection in patients have so far failed in clinical trials to increase the decay rate of the latent reservoir underscoring the need for continued study of HIV-1 latency. In this study, a genome-wide RNAi screen was performed to probe cellular factors involved in maintaining HIV-1 latency in HeLa cells latently infected with an HIV-1 reporter virus. Overall design: HeLa cells that were latently infected with an HIV-1 reporter virus (referred to as the experimental sample) and uninfected, parental HeLa cells (referred to as the reference control sample) were transduced with the GeneNet Genome-wide Human 50K Lentiviral shRNA Library (System Biosciences (SBI), Mountain View, CA). The library consists of approximately 200,000 shRNA constructs targeting about 38,000 human transcripts. It includes 1-4 shRNA constructs per gene, each targeting a different sequence within a specific gene. Transduced cells were selected with puromycin and cultured for a total of 17 days, which was experimentally determined to provide ample time for shRNA expression and knockdown of the target gene, as well as viral reactivation and viral protein-mediated cell death in the experimental sample. In other words, a negative selection protocol was used to identify shRNAs that activated latent virus by taking advantage of the cytotoxic effects of the HIV-1 viral protein Vpr. Following the culture period, cells were lysed and total RNA was isolated, reverse transcribed, amplified, and hybridized to an Affymetrix GeneChip Array (HG-U133+ 2.0) for identification. As the functional assay employed in this screen involved viral protein-mediated cell death upon the re-activation of latent HIV-1, signals from the reference control sample microarray that were at least three times greater than the corresponding signals from the experimental sample microarray were scored as “hits” and statistically analyzed further.
Project description:Metabolic alterations, such as oxidative stress, are hallmarks of HIV-1 infection. However, their influenceon the development of viral latency, and thus on HIV-1 persistence during antiretroviral therapy (ART),have just begun to be explored. We analyzed omics profiles ofin-vitroandin-vivomodels of infection byHIV-1 and its simian homolog SIVmac. We found that cells survive retroviral replication by upregulatingantioxidant pathways and intertwined iron import pathways. These changes are associated withremodeling of the redox sensitive promyelocytic leukemia protein nuclear bodies (PML NBs), an importantconstituent of nuclear architecture and a marker of HIV-1 latency. We found that PML is depleted inproductively infected cells and restored by ART. Moreover, we identified intracellular iron as a key linkbetween oxidative stress and PML depletion, thus supporting iron metabolism modulators aspharmacological tools to impair latency establishment.
Project description:The epigenetic mechanisms established by histone modifications may affect the transcriptional silencing of HIV-1 and viral latency. A systematic epigenome profiling could be applicable to develop new epigenetic diagnostic markers for detecting HIV-1 latency. In this study, histone modification profiles of HIV-1 latency cell lines were compared with those of uninfected CD4+ T cell line. The HIV-1 latency gave rise to differential histone modification regions. The differential enrichment patterns helped us to define potential effector genes leading to the viral latency. The histone H3K4me3 and H3K9ac profiles were obtained from the HIV-1 latency cell lines (NCHA1, NCHA2, and ACH2) and control CD4+ T cell line (A3.01)
Project description:Initiation of antiretroviral therapy during the earliest stages of HIV-1 infection may limit the seeding of a long-lasting viral reservoir, but long-term effects of early antiretroviral treatment initiation remain unknown. Here, we analyzed immunological and virological characteristics of nine patients who started antiretroviral therapy in primary HIV-1 infection and remained on suppressive treatment for >10 years; patients with similar treatment duration but initiation of therapy in chronic HIV-1 infection served as controls. We observed that independently of the timing of treatment initiation, HIV-1 DNA in CD4 T cells decayed exclusively during the initial 3-4 years of treatment; however, in patients who started antiretroviral therapy in acute infection, this decay occurred faster and was more pronounced, leading to substantially lower levels of cell-associated HIV-1 DNA after long-term treatment. Despite this smaller size, the viral CD4 T cell reservoir in persons with early treatment initiation consisted more dominantly of the long-lasting central-memory and T memory stem cells. Moreover, gene transcripts in CD4 T cells associated with the total viral CD4 T cell reservoir size frequently correlated with the relative proportion of these long-lived CD4 T cell subsets, suggesting shared gene expression signatures for maintaining HIV-1 persistence and preservation of long-lasting CD4 T cell subsets. Despite effective suppression of viral antigens for >10 years, HIV-1-specific T cell responses remained continuously detectable in both study groups. Together, these data suggest that although early HIV-1 treatment initiation, even when continued for >10 years, is unlikely to lead to viral eradication, the presence of low viral reservoirs and durable HIV-1 T cell responses may make such patients attractive candidates for future interventional studies aiming at HIV-1 eradication and cure. Overall design: We used Dynabeads Untouched Human CD4 T Cells kit (Invitrogen) for CD4 isolation from a median of 10 million PBMCs. RNA was extracted from CD4+ T cells using the mirVana miRNA Isolation Kit, Ambion. whole genome transcriptional profiling was performed using WG-DASL microarrays (Illumina) according to standard protocols. We included an cohort of elite controllers (n =10 ), patients long term HAART treated after the chronic phase of the infection (n=10) and patients long term HAART treated after the acute phase of the infection (n=8).