Catchet-MS identifies IKZF1-targeting Thalidomide analogues as novel HIV-1 latency reversal agents
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE196059 | GEO | 2022/02/06
REPOSITORIES: GEO
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Project description:HIV-1 infected patients virally suppressed by antiviral treatment harbor a persistent reservoir of replication competent latent HIV-1 infected cells, which constitute the main roadblock to a cure. A main strategy for HIV cure aims to stimulate viral gene expression in latently infected cells so that they can be cleared. Crucial for the design of drugs referred to as “latency-reversing agents” (LRAs) is the identification of molecular targets for latency reversal. The regulatory factors physically associated with and repressing the latent HIV-1 promoter or 5’LTR would provide ideal putative molecular targets for latency reversal. However, due to technical limitations, the comprehensive and unbiased identification of host proteins associated with the latent or active integrated HIV LTR in infected cells not been possible. Here we use dCas9 targeted chromatin and histone enrichment strategy coupled to mass spectrometry (Catchet-MS), to purify the locus-associated dCas9 bait, guided downstream of the HIV-1 transcriptional start site (TSS) in latent and activated HIV-1 infected T cells to identify the 5’LTR bound latent and active regulatory complexes. Catchet-MS identified both previously described as well as novel host factors distinctly associated with the latent versus transcriptionally active HIV-1 5’LTR. Within the identified factors we find the transcription factor IKZF1 to be a novel repressor of the HIV-1 promoter required for maintenance of latency, and thus a molecular target for latency reversal. Finally, we identify the FDA approved drug, Iberdomide, which targets IKZF1 for degradation to be a novel LRA, which reversed latency in latent ex vivo HIV-1 infected primary CD4+ T cells and in cells isolated from HIV-1 infected, aviremic participants.
2022-05-31 | PXD032975 | Pride
Project description:A leading pharmacological strategy towards HIV cure requires “shock” or activation of expression of the HIV genome in latently infected cells with Latency Reversal Agents (LRAs) followed by their subsequent clearance. As a source of bio-active molecules we used fungal secondary metabolites (extrolites) in a screen for novel LRAs. We used orthogonal mass spectrometry (MS) coupled to latency reversal bioassays, and identified gliotoxin (GTX) to potently reverse latency. GTX significantly induced HIV-1 gene expression in latent ex vivo infected primary cells and in CD4+ T cells from all aviremic HIV-1+ participants. RNA sequencing identified 7SK RNA to be most significantly downregulated in independent donors upon GTX treatment of CD4+ T cells. GTX disrupted the 7SK snRNP complex causing release of P-TEFb, which induced phosphorylation of RNA Pol II CTD, and increased HIV transcription. Our data highlight the power of combining low throughput bioassays, mycology and orthogonal mass spectrometry as an approach to screen for and characterize novel LRAs.
2020-08-31 | GSE135184 | GEO
Project description:HIV-1 latency results from a combination of tightly regulated molecular processes that act at distinct steps of HIV-1 gene expression. In an effort to elucidate the molecular players that govern viral latency, we previously performed a dCas9 chromatin immunoprecipitation coupled with mass spectrometry (Catchet-MS) and identified proteins bound differentially to the latent LTR that putatively promote HIV-1 latency. Here we characterize the Catchet-MS identified PCI domain-containing 2 (PCID2) protein to play a dual role in promoting HIV-1 latency by enforcing both HIV-1 transcription repression as well as post-transcriptional blocks. PCID2 bound the latent HIV-1 LTR and repressed transcription initiation during latency. Depletion of PCID2 remodeled the chromatin landscape at the HIV-1 promoter and resulted in transcriptional activation and reversal of latency. Immunoprecipitation coupled to Mass Spectrometry identified the PCID2 interacting proteins to include members of the spliceosome and other splicing regulators, including negative regulators of viral RNA alternative splicing. PCID2 depletion resulted in over-splicing of intron-containing HIV-1 RNA and mis-regulated expression of vRNA splice variants. Finally, consistent with its role in NXF1-mediated nascent RNA nucleocytoplasmic export as part of the TREX2 complex, PCID2 modulates export of completely spliced vRNA. In summary, we demonstrate that PCID2 is a previously unidentified factor involved in HIV-1 latency regulation which plays a dual role in blocking HIV-1 gene expression by acting on transcription initiation as well as viral RNA processing.
2024-06-16 | PXD043334 | Pride
Project description:HIV-1 latency results from tightly regulated molecular processes that act at distinct steps of HIV-1 gene expression. To elucidate the molecular players that govern latency, we previously performed a dCas9-chromatin immunoprecipitation coupled with mass spectrometry (Catchet-MS) and identified the interactome of the latent HIV-1 LTR. Here we characterize the Catchet-MS-identified PCI domain-containing 2 (PCID2) protein, a component of the TREX2 complex, to play a dual role in promoting HIV-1 latency by enforcing both transcriptional repression and post-transcriptional blocks to HIV-1 gene expression. PCID2 bound the latent HIV-1 LTR and repressed transcription initiation during latency. Depletion of PCID2 remodelled the chromatin landscape at the HIV-1 promoter and resulted in transcriptional activation and reversal of latency. Immunoprecipitation coupled to Mass Spectrometry identified PCID2-interacting proteins to include members of the spliceosome, including negative viral RNA (vRNA) alternative splicing regulators, and PCID2 depletion resulted in over-splicing of intron-containing vRNA and misregulated expression of vRNA splice variants in cell lines and primary cells obtained from people living with HIV-1. We demonstrate that MCM3AP and DSS1, two other RNA-binding TREX2 complex subunits that comprise the dock of the complex also inhibit transcription initiation and viral RNA alternative splicing during latency and similarly to PCID2 function as prominent latency associated repressors of HIV-1 gene expression. Thus, PCID2 is a novel HIV-1 latency-promoting factor, which in context of the TREX2 sub-complex PCID2-DSS1-MCM3AP blocks transcription and dysregulates vRNA processing.
2023-12-10 | GSE249455 | GEO
Project description:Molecular mechanisms of HIV-1 latency have been studied extensively to achieve a functional cure for the acquired immunodeficiency syndrome (AIDS). To develop more promising latency-reversing agents (LRAs) to efficiently reactivate the latent reservoir which is subsequently eliminated by immune surveillance, new therapeutic targets need to be evaluated. Here, we found that the Polycomb group (PcG) protein CBX4 contributes to HIV-1 latency in many latency models and primary CD4+ T cells. CBX4 forms nuclear bodies with liquid–liquid phase separation (LLPS) properties on the HIV-1 long terminal repeat (LTR). Further proteomics analysis revealed that CBX4 recruits EZH2 to CBX4 bodies and SUMOylates EZH2 utilizing its SUMO E3 ligase activity, which enhances the H3K27 methyltransferase activity of EZH2. Our results indicated that CBX4 bridges the Polycomb repressive complex 1 (PRC1) and PRC2, resulting in synergistically maintaining HIV-1 latency. Dissolution of phase-separated CBX4 bodies could be a potential intervention to reactivate latent HIV-1.
2022-01-14 | PXD031011 |
Project description:HIV-1 persists in individuals on ART in infected central (CM), transitional (TM) and effector memory (EM) CD4+ T cells. We developed LARA (latency and reversion assay), which facilitates the examination of HIV latency reversal in CM, TM and EM subsets in a single assay. Studies with latency reversing agents (LRAs) revealed responses specific to each subset, including compounds that significantly reversed latency in all subsets but with a range of efficiency (bryostatin) to those that demonstrated subset specificity (IL-15). Significantly, LARA has allowed the demonstration that EM cells display a more activated profile compared to CM, which translated to enhanced efficiency in responsiveness to multiple LRAs and allowed the identification of mechanisms associated with the compounds that reactivate latent HIV in all subsets. Understanding the responsiveness of memory CD4+ T cells subsets to LRAs will accelerate the development of anti-latency therapy to interfering with viral persistence in vivo.
2018-01-26 | GSE94150 | GEO
Project description:HIV-1 persists in individuals on ART in infected central (CM), transitional (TM) and effector memory (EM) CD4+ T cells. We developed LARA (latency and reversion assay), which facilitates the examination of HIV latency reversal in CM, TM and EM subsets in a single assay. Studies with latency reversing agents (LRAs) revealed responses specific to each subset, including compounds that significantly reversed latency in all subsets but with a range of efficiency (bryostatin) to those that demonstrated subset specificity (IL-15). Significantly, LARA has allowed the demonstration that EM cells display a more activated profile compared to CM, which translated to enhanced efficiency in responsiveness to multiple LRAs and allowed the identification of mechanisms associated with the compounds that reactivate latent HIV in all subsets. Understanding the responsiveness of memory CD4+ T cells subsets to LRAs will accelerate the development of anti-latency therapy to interfering with viral persistence in vivo.
2018-01-26 | GSE94149 | GEO
Project description:The latent viral reservoir represents one of the major barriers of curing HIV. Focus on the “kick and kill” approach, in which virus expression is reactivated then cells producing virus are selectively depleted, has led to the discovery of many latency reversing agents (LRAs) that can reactivate latently integrated virus and further our understanding of the mechanisms driving HIV latency and latency reversal. Thus far, individual compounds have yet to be robust enough to work as a therapy, highlighting the importance of identifying new compounds that target novel pathways and synergize with known LRAs. In this study, we identified a promising LRA, NSC95397, from a screen of ~4250 compounds in J-Lat cell lines. We validated that NSC95397 reactivates latent viral transcription and protein expression from cells with unique integration events. Co-treating cells with NSC95397 and known LRAs demonstrated that NSC95397 has the potential to synergize with different drugs under both standard normoxic and physiological hypoxic conditions. We showed that NSC95397 does not globally increase open chromatin, and bulk RNA sequencing revealed that NSC95397 does not greatly change cellular transcription. Instead, NSC95397 downregulates many pathways key to metabolism, cell growth, and DNA repair – highlighting the potential of these pathways in regulating HIV latency. Overall, we identified NSC95397 as a novel LRA that does not alter global transcription, that shows potential for synergy with known LRAs, and that may act through novel pathways not previously recognized for their ability to modulate HIV latency.
2024-08-31 | GSE241617 | GEO
Project description:HIV-1 latency is a major obstacle to achieve a functional cure for AIDS. To eradicate the viral reservoir, one of the strategies is to specifically reactivate HIV-1-infected cells and followed by elimination with potent immune surveillance. However, present latency-reversing agents (LRAs) are quite dissatisfactory because of their high toxicity and low efficiency. New targets need to be identified to develop more promising LRAs. Here, we found that histone chaperone chromatin assembly factor 1 (CAF-1) promotes HIV-1 latency by forming versatile suppressive nuclear bodies. CAF-1 plays a leading role for the formation of bodies recruiting multi-layer suppressive epigenetic modifiers and maintainers, and is of the characteristic of liquid-liquid phase separation (LLPS). Three distinct disordered regions of CHAF1A subunit coalesce CAF-1 body components by forming LLPS and play a key in maintaining HIV-1 latency. Therefore, disruptive induction of phase-separated CAF-1 body could be an important strategy to reactivate latent HIV-1.
2021-02-09 | GSE166337 | GEO
Project description:Antiretroviral therapy (ART) is not curative due to the existence of cellular reservoirs of latent HIV-1 that persist during therapy 1. Current research efforts to cure HIV-1 infection include “shock and kill” strategies to disrupt latency using small molecules or latency-reversing agents (LRAs) to induce expression of HIV-1 enabling cytotoxic immune cells to eliminate infected cells 2. However, the modest success of current LRAs urges the field to identify novel drugs with increased clinical efficacy 3,4. Aminobisphosphonates that include pamidronate, zoledronate, or alendronate, are the first-line treatment of bone-related diseases including osteoporosis and bone malignancies 5. Here, we show the use of aminobisphosphonates as a novel class of LRA: we found in ex vivo assays using primary cells from ART-suppressed people living with HIV-1 that aminobisphosphonates induce HIV-1 from latency to levels that are comparable to the T cell activator phytohemagglutinin. RNA sequencing and mechanistic data suggested that reactivation may occur through activation of the activator protein 1 signaling pathway. Stored samples from a prior clinical trial aimed at analyzing the effect of alendronate on bone mineral density, provided further of alendronate-mediated latency reversal and activation of immune effector cells.Decay of the reservoir measured by IPDA was however not detected. Our results demonstrate the novel use of aminobisphosphonates to reverse HIV-1 latency while inducing immune effector functions. This preliminary evidence merits further investigation in a controlled clinical setting possibly in combination with therapeutic vaccination.
2023-09-13 | GSE224546 | GEO