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Prelli Bozzo C, Laliberté A, De Luna A, Pastorio C, Regensburger K, Krebs S, Graf A, Blum H, Volcic M, Sparrer KMJ, Kirchhoff F. Replication competent HIV-guided CRISPR screen identifies antiviral factors including targets of the accessory protein Nef. Nat Commun 2024; 15:3813. [PMID: 38714682 PMCID: PMC11076291 DOI: 10.1038/s41467-024-48228-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 04/24/2024] [Indexed: 05/10/2024] Open
Abstract
Innate antiviral factors are essential for effective defense against viral pathogens. However, the identity of major restriction mechanisms remains elusive. Current approaches to discover antiviral factors usually focus on the initial steps of viral replication and are limited to a single round of infection. Here, we engineered libraries of >1500 replication-competent HIV-1 constructs each expressing a single gRNAs to target >500 cellular genes for virus-driven discovery of antiviral factors. Passaging in CD4+ T cells robustly enriched HIV-1 encoding sgRNAs against GRN, CIITA, EHMT2, CEACAM3, CC2D1B and RHOA by >50-fold. Using an HIV-1 library lacking the accessory nef gene, we identified IFI16 as a Nef target. Functional analyses in cell lines and primary CD4+ T cells support that the HIV-driven CRISPR screen identified restriction factors targeting virus entry, transcription, release and infectivity. Our HIV-guided CRISPR technique enables sensitive discovery of physiologically relevant cellular defense factors throughout the entire viral replication cycle.
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Affiliation(s)
| | - Alexandre Laliberté
- Institute of Molecular Virology, Ulm University Medical Center, 89081, Ulm, Germany
| | - Aurora De Luna
- Institute of Molecular Virology, Ulm University Medical Center, 89081, Ulm, Germany
| | - Chiara Pastorio
- Institute of Molecular Virology, Ulm University Medical Center, 89081, Ulm, Germany
| | - Kerstin Regensburger
- Institute of Molecular Virology, Ulm University Medical Center, 89081, Ulm, Germany
| | - Stefan Krebs
- Laboratory for Functional Genome Analysis Gene Center, LMU Munich, 81377, Munich, Germany
| | - Alexander Graf
- Laboratory for Functional Genome Analysis Gene Center, LMU Munich, 81377, Munich, Germany
| | - Helmut Blum
- Laboratory for Functional Genome Analysis Gene Center, LMU Munich, 81377, Munich, Germany
| | - Meta Volcic
- Institute of Molecular Virology, Ulm University Medical Center, 89081, Ulm, Germany
| | | | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, 89081, Ulm, Germany.
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Nguyen K, Karn J. The sounds of silencing: dynamic epigenetic control of HIV latency. Curr Opin HIV AIDS 2024; 19:102-109. [PMID: 38547337 PMCID: PMC10990033 DOI: 10.1097/coh.0000000000000850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
PURPOSE OF REVIEW This review highlights advances in understanding the epigenetic control mechanisms that regulate HIV-1 latency mechanisms in T-cells and microglial cells and describes the potential of current therapeutic approaches targeting the epigenetic machinery to eliminate or block the HIV-1 latent reservoir. RECENT FINDINGS Large-scale unbiased CRISPR-Cas9 library-based screenings, coupled with biochemical studies, have comprehensively identified the epigenetic factors pivotal in regulating HIV-1 latency, paving the way for potential novel targets in therapeutic development. These studies also highlight how the bivalency observed at the HIV-1 5'LTR primes latent proviruses for rapid reactivation. SUMMARY The HIV-1 latent is established very early during infection, and its persistence is the major obstacle to achieving an HIV-1 cure. Here, we present a succinct summary of the latest research findings, shedding light on the pivotal roles played by host epigenetic machinery in the control of HIV-1 latency. Newly uncovered mechanisms permitting rapid reversal of epigenetic restrictions upon viral reactivation highlight the formidable challenges of achieving enduring and irreversible epigenetic silencing of HIV-1.
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Affiliation(s)
- Kien Nguyen
- Department of Molecular Biology & Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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Mbonye U, Karn J. The cell biology of HIV-1 latency and rebound. Retrovirology 2024; 21:6. [PMID: 38580979 PMCID: PMC10996279 DOI: 10.1186/s12977-024-00639-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024] Open
Abstract
Transcriptionally latent forms of replication-competent proviruses, present primarily in a small subset of memory CD4+ T cells, pose the primary barrier to a cure for HIV-1 infection because they are the source of the viral rebound that almost inevitably follows the interruption of antiretroviral therapy. Over the last 30 years, many of the factors essential for initiating HIV-1 transcription have been identified in studies performed using transformed cell lines, such as the Jurkat T-cell model. However, as highlighted in this review, several poorly understood mechanisms still need to be elucidated, including the molecular basis for promoter-proximal pausing of the transcribing complex and the detailed mechanism of the delivery of P-TEFb from 7SK snRNP. Furthermore, the central paradox of HIV-1 transcription remains unsolved: how are the initial rounds of transcription achieved in the absence of Tat? A critical limitation of the transformed cell models is that they do not recapitulate the transitions between active effector cells and quiescent memory T cells. Therefore, investigation of the molecular mechanisms of HIV-1 latency reversal and LRA efficacy in a proper physiological context requires the utilization of primary cell models. Recent mechanistic studies of HIV-1 transcription using latently infected cells recovered from donors and ex vivo cellular models of viral latency have demonstrated that the primary blocks to HIV-1 transcription in memory CD4+ T cells are restrictive epigenetic features at the proviral promoter, the cytoplasmic sequestration of key transcription initiation factors such as NFAT and NF-κB, and the vanishingly low expression of the cellular transcription elongation factor P-TEFb. One of the foremost schemes to eliminate the residual reservoir is to deliberately reactivate latent HIV-1 proviruses to enable clearance of persisting latently infected cells-the "Shock and Kill" strategy. For "Shock and Kill" to become efficient, effective, non-toxic latency-reversing agents (LRAs) must be discovered. Since multiple restrictions limit viral reactivation in primary cells, understanding the T-cell signaling mechanisms that are essential for stimulating P-TEFb biogenesis, initiation factor activation, and reversing the proviral epigenetic restrictions have become a prerequisite for the development of more effective LRAs.
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Affiliation(s)
- Uri Mbonye
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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Wu SY, Lai HT, Sanjib Banerjee N, Ma Z, Santana JF, Wei S, Liu X, Zhang M, Zhan J, Chen H, Posner B, Chen Y, Price DH, Chow LT, Zhou J, Chiang CM. IDR-targeting compounds suppress HPV genome replication via disruption of phospho-BRD4 association with DNA damage response factors. Mol Cell 2024; 84:202-220.e15. [PMID: 38103559 PMCID: PMC10843765 DOI: 10.1016/j.molcel.2023.11.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 10/14/2023] [Accepted: 11/16/2023] [Indexed: 12/19/2023]
Abstract
Compounds binding to the bromodomains of bromodomain and extra-terminal (BET) family proteins, particularly BRD4, are promising anticancer agents. Nevertheless, side effects and drug resistance pose significant obstacles in BET-based therapeutics development. Using high-throughput screening of a 200,000-compound library, we identified small molecules targeting a phosphorylated intrinsically disordered region (IDR) of BRD4 that inhibit phospho-BRD4 (pBRD4)-dependent human papillomavirus (HPV) genome replication in HPV-containing keratinocytes. Proteomic profiling identified two DNA damage response factors-53BP1 and BARD1-crucial for differentiation-associated HPV genome amplification. pBRD4-mediated recruitment of 53BP1 and BARD1 to the HPV origin of replication occurs in a spatiotemporal and BRD4 long (BRD4-L) and short (BRD4-S) isoform-specific manner. This recruitment is disrupted by phospho-IDR-targeting compounds with little perturbation of the global transcriptome and BRD4 chromatin landscape. The discovery of these protein-protein interaction inhibitors (PPIi) not only demonstrates the feasibility of developing PPIi against phospho-IDRs but also uncovers antiviral agents targeting an epigenetic regulator essential for virus-host interaction and cancer development.
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Affiliation(s)
- Shwu-Yuan Wu
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hsien-Tsung Lai
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - N Sanjib Banerjee
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Zonghui Ma
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA
| | - Juan F Santana
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52242, USA
| | - Shuguang Wei
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xisheng Liu
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Meirong Zhang
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Jian Zhan
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Haiying Chen
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA
| | - Bruce Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yadong Chen
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - David H Price
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52242, USA
| | - Louise T Chow
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jia Zhou
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA.
| | - Cheng-Ming Chiang
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Hafer TL, Felton A, Delgado Y, Srinivasan H, Emerman M. A CRISPR Screen of HIV Dependency Factors Reveals That CCNT1 Is Non-Essential in T Cells but Required for HIV-1 Reactivation from Latency. Viruses 2023; 15:1863. [PMID: 37766271 PMCID: PMC10535513 DOI: 10.3390/v15091863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
We sought to explore the hypothesis that host factors required for HIV-1 replication also play a role in latency reversal. Using a CRISPR gene library of putative HIV dependency factors, we performed a screen to identify genes required for latency reactivation. We identified several HIV-1 dependency factors that play a key role in HIV-1 latency reactivation including ELL, UBE2M, TBL1XR1, HDAC3, AMBRA1, and ALYREF. The knockout of Cyclin T1 (CCNT1), a component of the P-TEFb complex that is important for transcription elongation, was the top hit in the screen and had the largest effect on HIV latency reversal with a wide variety of latency reversal agents. Moreover, CCNT1 knockout prevents latency reactivation in a primary CD4+ T cell model of HIV latency without affecting the activation of these cells. RNA sequencing data showed that CCNT1 regulates HIV-1 proviral genes to a larger extent than any other host gene and had no significant effects on RNA transcripts in primary T cells after activation. We conclude that CCNT1 function is non-essential in T cells but is absolutely required for HIV latency reversal.
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Affiliation(s)
- Terry L. Hafer
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195, USA;
| | - Abby Felton
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Yennifer Delgado
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Harini Srinivasan
- Bioinformatics Shared Resource, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Michael Emerman
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
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Hafer TL, Felton A, Delgado Y, Srinivasan H, Emerman M. A CRISPR screen of HIV dependency factors reveals CCNT1 is non-essential in T cells but required for HIV-1 reactivation from latency. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.28.551016. [PMID: 37546973 PMCID: PMC10402164 DOI: 10.1101/2023.07.28.551016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
We sought to explore the hypothesis that host factors required for HIV-1 replication also play a role in latency reversal. Using a CRISPR gene library of putative HIV dependency factors, we performed a screen to identify genes required for latency reactivation. We identified several HIV-1 dependency factors that play a key role in HIV-1 latency reactivation including ELL , UBE2M , TBL1XR1 , HDAC3 , AMBRA1 , and ALYREF . Knockout of Cyclin T1 ( CCNT1 ), a component of the P-TEFb complex important for transcription elongation, was the top hit in the screen and had the largest effect on HIV latency reversal with a wide variety of latency reversal agents. Moreover, CCNT1 knockout prevents latency reactivation in a primary CD4+ T cell model of HIV latency without affecting activation of these cells. RNA sequencing data showed that CCNT1 regulates HIV-1 proviral genes to a larger extent than any other host gene and had no significant effects on RNA transcripts in primary T cells after activation. We conclude that CCNT1 function is redundant in T cells but is absolutely required for HIV latency reversal.
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Affiliation(s)
- Terry L Hafer
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195, USA
| | - Abby Felton
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Yennifer Delgado
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Harini Srinivasan
- Bioinformatics Shared Resource, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Michael Emerman
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
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A Virus-Packageable CRISPR System Identifies Host Dependency Factors Co-Opted by Multiple HIV-1 Strains. mBio 2023; 14:e0000923. [PMID: 36744886 PMCID: PMC9973025 DOI: 10.1128/mbio.00009-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
At each stage of the HIV life cycle, host cellular proteins are hijacked by the virus to establish and enhance infection. We adapted the virus packageable HIV-CRISPR screening technology at a genome-wide scale to comprehensively identify host factors that affect HIV replication in a human T cell line. Using a smaller, targeted HIV Dependency Factor (HIVDEP) sublibrary, we then performed screens across HIV strains representing different clades and with different biological properties to define which T cell host factors are important across multiple HIV strains. Nearly 90% of the genes selected across various host pathways validated in subsequent assays as bona fide host dependency factors, including numerous proteins not previously reported to play roles in HIV biology, such as UBE2M, MBNL1, FBXW7, PELP1, SLC39A7, and others. Our ranked list of screen hits across diverse HIV-1 strains form a resource of HIV dependency factors for future investigation of host proteins involved in HIV biology. IMPORTANCE With a small genome of ~9.2 kb that encodes 14 major proteins, HIV must hijack host cellular machinery to successfully establish infection. These host proteins necessary for HIV replication are called "dependency factors." Whole-genome, and then targeted screens were done to try to comprehensively identify all dependency factors acting throughout the HIV replication cycle. Many host processes were identified and validated as critical for HIV replication across multiple HIV strains.
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