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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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Ranga U, Panchapakesan A, Saini C. HIV-1 subtypes and latent reservoirs. Curr Opin HIV AIDS 2024; 19:87-92. [PMID: 38169308 DOI: 10.1097/coh.0000000000000835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
PURPOSE OF REVIEW We explore the current status of research on HIV-1 subtype-specific variations and their impact on HIV-1 latency. We also briefly address the controversy surrounding the decision-making process governing the ON/OFF states of HIV-1 transcription, specifically focusing on the regulatory elements, the long terminal repeat (LTR), and Tat. Understanding the decision-making process is crucial for developing effective intervention strategies, such as the 'shock-and-kill' approach, to reactivate latent HIV-1. RECENT FINDINGS Attention has been drawn to subtype-specific transcription factor binding site (TFBS) variations and the possible impact of these variations on viral latency. Further, diverse subtype-specific assays have been developed to quantify the latent viral reservoirs. One interesting observation is the relatively larger latent reservoirs in HIV-1B infection than those of other viral subtypes, which needs rigorous validation. The emergence of LTR-variant viral strains in HIV-1C demonstrating significantly higher levels of latency reversal has been reported. SUMMARY Despite persistent and substantial efforts, latent HIV-1 remains a formidable challenge to a functional cure. Determined and continued commitment is needed to understand the ON/OFF decision-making process of HIV-1 latency, develop rigorous assays for accurately quantifying the latent reservoirs, and identify potent latency-reversing agents and cocktails targeting multiple latency stages. The review emphasizes the importance of including diverse viral subtypes in future latency research.
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Affiliation(s)
- Udaykumar Ranga
- HIV-AIDS Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka
| | - Arun Panchapakesan
- Molecular Biology Laboratory, Y R Gaitonde Centre for AIDS Research and Education (YRG CARE), Chennai, Tamil Nadu, India
| | - Chhavi Saini
- HIV-AIDS Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, Karnataka
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Sanders-Beer BE, Archin NM, Brumme ZL, Busch MP, Deleage C, O'Doherty U, Hughes SH, Jerome KR, Jones RB, Karn J, Kearney MF, Keele BF, Kulpa DA, Laird GM, Li JZ, Lichterfeld MD, Nussenzweig MC, Persaud D, Yukl SA, Siliciano RF, Mellors JW. Current HIV/SIV Reservoir Assays for Preclinical and Clinical Applications: Recommendations from the Experts 2022 NIAID Workshop Summary. AIDS Res Hum Retroviruses 2023; 40:7-21. [PMID: 37126090 DOI: 10.1089/aid.2022.0188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Since the first HIV-cured person was reported in 2009, a strong interest in developing highly sensitive HIV and SIV reservoir assays has emerged. In particular, the question arose about the comparative value of state-of-the-art assays to measure and characterize the HIV reservoir, and how these assays can be applied to accurately detect changes in the reservoir during efforts to develop a cure for HIV infection. Second, it is important to consider the impact on the outcome of clinical trials if these relatively new HIV reservoir assays are incorporated into clinical trial endpoints and/or used for clinical decision-making. To understand the advantages and limitations and the regulatory implications of HIV reservoir assays, the National Institute of Allergy and Infectious Diseases (NIAID) sponsored and convened a meeting on September 16, 2022, to discuss the state of knowledge concerning these questions and best practices for selecting HIV reservoir assays for a particular research question or clinical trial protocol.
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Affiliation(s)
- Brigitte E Sanders-Beer
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Nancie M Archin
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Zabrina L Brumme
- Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Michael P Busch
- Vitalant Research Institute, University of California, San Francisco, California, USA
| | - Claire Deleage
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research (FNLCR), Frederick, Maryland, USA
| | - Una O'Doherty
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Stephen H Hughes
- HIV Dynamics and Replication Program, CCR, National Cancer Institute, Frederick, Maryland, USA
| | - Keith R Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, and Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - R Brad Jones
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mary F Kearney
- HIV Dynamics and Replication Program, CCR, National Cancer Institute, Frederick, Maryland, USA
| | - Brandon F Keele
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research (FNLCR), Frederick, Maryland, USA
| | - Deanna A Kulpa
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | - Jonathan Z Li
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mathias D Lichterfeld
- Brigham and Women's Hospital and Ragon Institute of MGH, MIT and Harvard, Boston, Massachusetts, USA
| | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, New York, USA
| | - Deborah Persaud
- Department of Pediatric Infectious Disease, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Steven A Yukl
- Department of Medicine, University of California San Francisco (UCSF) and San Francisco VA Medical Center, San Francisco, California, USA
| | - Robert F Siliciano
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - John W Mellors
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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Mbonye U, Kizito F, Karn J. New insights into transcription elongation control of HIV-1 latency and rebound. Trends Immunol 2023; 44:60-71. [PMID: 36503686 DOI: 10.1016/j.it.2022.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 12/13/2022]
Abstract
Antiretroviral therapy reduces circulating HIV-1 to undetectable amounts but does not eliminate the virus due to the persistence of a stable reservoir of latently infected cells. The reservoir is maintained both by proliferation of latently infected cells and by reseeding from reactivated cells. A major challenge for the field is to find safe and effective methods to eliminate this source of rebounding HIV-1. Studies on the molecular mechanisms leading to HIV-1 latency and reactivation are being transformed using latency models in primary and patient CD4+ T cells. These studies have revealed the central role played by the biogenesis of the transcription elongation factor P-TEFb (Positive Transcription Elongation Factor b) and its recruitment to proviral HIV-1, for the maintenance of viral latency and the control of viral reactivation.
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Affiliation(s)
- Uri Mbonye
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA
| | - Fredrick Kizito
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA.
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Nolan DJ, Rose R, Zhang R, Leong A, Fogel GB, Scholte LLS, Bethony JM, Bracci P, Lamers SL, McGrath MS. The Persistence of HIV Diversity, Transcription, and Nef Protein in Kaposi's Sarcoma Tumors during Antiretroviral Therapy. Viruses 2022; 14:v14122774. [PMID: 36560778 PMCID: PMC9782636 DOI: 10.3390/v14122774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/05/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Epidemic Kaposi's sarcoma (KS), defined by co-infection with Human Herpes Virus 8 (HHV-8) and the Human Immunodeficiency Virus (HIV), is a major cause of mortality in sub-Saharan Africa. Antiretroviral therapy (ART) significantly reduces the risk of developing KS, and for those with KS, tumors frequently resolve with ART alone. However, for unknown reasons, a significant number of KS cases do not resolve and can progress to death. To explore how HIV responds to ART in the KS tumor microenvironment, we sequenced HIV env-nef found in DNA and RNA isolated from plasma, peripheral blood mononuclear cells, and tumor biopsies, before and after ART, in four Ugandan study participants who had unresponsive or progressive KS after 180-250 days of ART. We performed immunohistochemistry experiments to detect viral proteins in matched formalin-fixed tumor biopsies. Our sequencing results showed that HIV diversity and RNA expression in KS tumors are maintained after ART, despite undetectable plasma viral loads. The presence of spliced HIV transcripts in KS tumors after ART was consistent with a transcriptionally active viral reservoir. Immunohistochemistry staining found colocalization of HIV Nef protein and tissue-resident macrophages in the KS tumors. Overall, our results demonstrated that even after ART reduced plasma HIV viral load to undetectable levels and restored immune function, HIV in KS tumors continues to be transcriptionally and translationally active, which could influence tumor maintenance and progression.
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Affiliation(s)
- David J. Nolan
- Bioinfoexperts, LLC, Thibodaux, LA 70301, USA
- Correspondence:
| | | | - Rongzhen Zhang
- Departments of Laboratory Medicine, Pathology and Medicine, The University of California at San Francisco, San Francisco, CA 94110, USA
| | - Alan Leong
- Departments of Laboratory Medicine, Pathology and Medicine, The University of California at San Francisco, San Francisco, CA 94110, USA
| | | | - Larissa L. S. Scholte
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC 20037, USA
| | - Jeffrey M. Bethony
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC 20037, USA
| | - Paige Bracci
- The AIDS and Cancer Specimen Resource, San Francisco, CA 94110, USA
| | | | - Michael S. McGrath
- Departments of Laboratory Medicine, Pathology and Medicine, The University of California at San Francisco, San Francisco, CA 94110, USA
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