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Cellular Targets of HIV-1 Protease: Just the Tip of the Iceberg? Viruses 2023; 15:v15030712. [PMID: 36992421 PMCID: PMC10053624 DOI: 10.3390/v15030712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/05/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
Human immunodeficiency virus 1 (HIV-1) viral protease (PR) is one of the most studied viral enzymes and a crucial antiviral target. Despite its well-characterized role in virion maturation, an increasing body of research is starting to focus on its ability to cleave host cell proteins. Such findings are apparently in contrast with the dogma of HIV-1 PR activity being restricted to the interior of nascent virions and suggest catalytic activity within the host cell environment. Given the limited amount of PR present in the virion at the time of infection, such events mainly occur during late viral gene expression, mediated by newly synthesized Gag-Pol polyprotein precursors, rather than before proviral integration. HIV-1 PR mainly targets proteins involved in three different processes: those involved in translation, those controlling cell survival, and restriction factors responsible for innate/intrinsic antiviral responses. Indeed, by cleaving host cell translation initiation factors, HIV-1 PR can impair cap-dependent translation, thus promoting IRES-mediated translation of late viral transcripts and viral production. By targeting several apoptotic factors, it modulates cell survival, thus promoting immune evasion and viral dissemination. Additionally, HIV-1 PR counteracts restriction factors incorporated in the virion that would otherwise interfere with nascent virus vitality. Thus, HIV-1 PR appears to modulate host cell function at different times and locations during its life cycle, thereby ensuring efficient viral persistency and propagation. However, we are far from having a complete picture of PR-mediated host cell modulation, which is emerging as a field that needs further investigation.
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Chen M, Li M, Budai MM, Rice AP, Kimata JT, Mohan M, Wang J. Clearance of HIV-1 or SIV reservoirs by promotion of apoptosis and inhibition of autophagy: Targeting intracellular molecules in cure-directed strategies. J Leukoc Biol 2022; 112:1245-1259. [PMID: 35362118 PMCID: PMC9522917 DOI: 10.1002/jlb.4mr0222-606] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/15/2022] [Indexed: 12/24/2022] Open
Abstract
The reservoirs of the HIV display cellular properties resembling long-lived immune memory cells that could be exploited for viral clearance. Our interest in developing a cure for HIV stems from the studies of immunologic memory against infections. We and others have found that long-lived immune memory cells employ prosurvival autophagy and antiapoptotic mechanisms to protect their longevity. Here, we describe the rationale for the development of an approach to clear HIV-1 by selective elimination of host cells harboring replication-competent HIV (SECH). While reactivation of HIV-1 in the host cells with latency reversing agents (LRAs) induces viral gene expression leading to cell death, LRAs also simultaneously up-regulate prosurvival antiapoptotic molecules and autophagy. Mechanistically, transcription factors that promote HIV-1 LTR-directed gene expression, such as NF-κB, AP-1, and Hif-1α, can also enhance the expression of cellular genes essential for cell survival and metabolic regulation, including Bcl-xL, Mcl-1, and autophagy genes. In the SECH approach, we inhibit the prosurvival antiapoptotic molecules and autophagy induced by LRAs, thereby allowing maximum killing of host cells by the induced HIV-1 proteins. SECH treatments cleared HIV-1 infections in humanized mice in vivo and in HIV-1 patient PBMCs ex vivo. SECH also cleared infections by the SIV in rhesus macaque PBMCs ex vivo. Research efforts are underway to improve the efficacy and safety of SECH and to facilitate the development of SECH as a therapeutic approach for treating people with HIV.
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Affiliation(s)
- Min Chen
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
| | - Min Li
- Immunobiology and Transplant Science Center, Department of Surgery, Houston Methodist Research Institute, Houston, Texas, USA
| | - Marietta M. Budai
- Immunobiology and Transplant Science Center, Department of Surgery, Houston Methodist Research Institute, Houston, Texas, USA
| | - Andrew P. Rice
- Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, Texas, USA
| | - Jason T. Kimata
- Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, Texas, USA
| | - Mahesh Mohan
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Jin Wang
- Immunobiology and Transplant Science Center, Department of Surgery, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Surgery, Weill Cornell Medical College, Cornell University, New York, New York, USA
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Chandrasekar AP, Badley AD. Prime, shock and kill: BCL-2 inhibition for HIV cure. Front Immunol 2022; 13:1033609. [PMID: 36341439 PMCID: PMC9631312 DOI: 10.3389/fimmu.2022.1033609] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/07/2022] [Indexed: 05/30/2024] Open
Abstract
While modern HIV therapy can effectively suppress viral replication, the persistence of the latent reservoir posits the greatest hurdle to complete cure. The "shock and kill" strategy is under investigation for HIV therapy, aiming to reactivate latent HIV, and subsequently eliminate it through anti-retroviral therapy and host immune function. However, thus far, studies have yielded suboptimal results, stemming from a combination of ineffective latency reversal and poor immune clearance. Concomitantly, studies have now revealed the importance of the BCL-2 anti-apoptotic protein as a critical mediator of infected cell survival, reservoir maintenance and immune evasion in HIV. Furthermore, BCL-2 inhibitors are now recognized for their anti-HIV effects in pre-clinical studies. This minireview aims to examine the intersection of BCL-2 inhibition and current shock and kill efforts, hoping to inform future studies which may ultimately yield a cure for HIV.
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Affiliation(s)
- Aswath P. Chandrasekar
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
- Division of Infectious Diseases, Mayo Clinic, Rochester, MN, United States
| | - Andrew D. Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester, MN, United States
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN, United States
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4
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Kim JG, Shan L. Beyond Inhibition: A Novel Strategy of Targeting HIV-1 Protease to Eliminate Viral Reservoirs. Viruses 2022; 14:1179. [PMID: 35746649 PMCID: PMC9231271 DOI: 10.3390/v14061179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/23/2022] [Accepted: 05/26/2022] [Indexed: 02/06/2023] Open
Abstract
HIV-1 protease (PR) is a viral enzyme that cleaves the Gag and Gag-Pol polyprotein precursors to convert them into their functional forms, a process which is essential to generate infectious viral particles. Due to its broad substrate specificity, HIV-1 PR can also cleave certain host cell proteins. Several studies have identified host cell substrates of HIV-1 PR and described the potential impact of their cleavage on HIV-1-infected cells. Of particular interest is the interaction between PR and the caspase recruitment domain-containing protein 8 (CARD8) inflammasome. A recent study demonstrated that CARD8 can sense HIV-1 PR activity and induce cell death. While PR typically has low levels of intracellular activity prior to viral budding, premature PR activation can be achieved using certain non-nucleoside reverse transcriptase inhibitors (NNRTIs), resulting in CARD8 cleavage and downstream pyroptosis. Used together with latency reversal agents, the induction of premature PR activation to trigger CARD8-mediated cell killing may help eliminate latent reservoirs in people living with HIV. This represents a novel strategy of utilizing PR as an antiviral target through premature activation rather than inhibition. In this review, we discuss the viral and host substrates of HIV-1 protease and highlight potential applications and advantages of targeting CARD8 sensing of HIV-1 PR.
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Affiliation(s)
| | - Liang Shan
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, Saint Louis, MO 63110, USA;
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5
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Kroemer G, Galassi C, Zitvogel L, Galluzzi L. Immunogenic cell stress and death. Nat Immunol 2022; 23:487-500. [PMID: 35145297 DOI: 10.1038/s41590-022-01132-2] [Citation(s) in RCA: 448] [Impact Index Per Article: 224.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/07/2022] [Indexed: 12/20/2022]
Abstract
Dying mammalian cells emit numerous signals that interact with the host to dictate the immunological correlates of cellular stress and death. In the absence of reactive antigenic determinants (which is generally the case for healthy cells), such signals may drive inflammation but cannot engage adaptive immunity. Conversely, when cells exhibit sufficient antigenicity, as in the case of infected or malignant cells, their death can culminate with adaptive immune responses that are executed by cytotoxic T lymphocytes and elicit immunological memory. Suggesting a key role for immunogenic cell death (ICD) in immunosurveillance, both pathogens and cancer cells evolved strategies to prevent the recognition of cell death as immunogenic. Intriguingly, normal cells succumbing to conditions that promote the formation of post-translational neoantigens (for example, oxidative stress) can also drive at least some degree of antigen-specific immunity, pointing to a novel implication of ICD in the etiology of non-infectious, non-malignant disorders linked to autoreactivity.
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Affiliation(s)
- Guido Kroemer
- Equipe labellisée par la Ligue contre le cancer, Centre de Recherche des Cordeliers, INSERM U1138, Sorbonne Université, Université de Paris, Institut Universitaire de France, Paris, France. .,Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Center, Villejuif, France. .,Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France.
| | - Claudia Galassi
- Department of Radiation Oncology, Weill Cornell Medical College, New York, NY, USA
| | - Laurence Zitvogel
- Gustave Roussy Comprehensive Cancer Institute, Villejuif, France.,Université Paris Saclay, Faculty of Medicine, Le Kremlin-Bicêtre, France.,INSERM U1015, Villejuif, France.,Equipe labellisée par la Ligue contre le cancer, Villejuif, France.,Center of Clinical Investigations in Biotherapies of Cancer (CICBT) BIOTHERIS, Villejuif, France
| | - Lorenzo Galluzzi
- Department of Radiation Oncology, Weill Cornell Medical College, New York, NY, USA. .,Sandra and Edward Meyer Cancer Center, New York, NY, USA. .,Caryl and Israel Englander Institute for Precision Medicine, New York, NY, USA.
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6
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Perry C, Rayat ACME. Lentiviral Vector Bioprocessing. Viruses 2021; 13:268. [PMID: 33572347 PMCID: PMC7916122 DOI: 10.3390/v13020268] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/11/2022] Open
Abstract
Lentiviral vectors (LVs) are potent tools for the delivery of genes of interest into mammalian cells and are now commonly utilised within the growing field of cell and gene therapy for the treatment of monogenic diseases and adoptive therapies such as chimeric antigen T-cell (CAR-T) therapy. This is a comprehensive review of the individual bioprocess operations employed in LV production. We highlight the role of envelope proteins in vector design as well as their impact on the bioprocessing of lentiviral vectors. An overview of the current state of these operations provides opportunities for bioprocess discovery and improvement with emphasis on the considerations for optimal and scalable processing of LV during development and clinical production. Upstream culture for LV generation is described with comparisons on the different transfection methods and various bioreactors for suspension and adherent producer cell cultivation. The purification of LV is examined, evaluating different sequences of downstream process operations for both small- and large-scale production requirements. For scalable operations, a key focus is the development in chromatographic purification in addition to an in-depth examination of the application of tangential flow filtration. A summary of vector quantification and characterisation assays is also presented. Finally, the assessment of the whole bioprocess for LV production is discussed to benefit from the broader understanding of potential interactions of the different process options. This review is aimed to assist in the achievement of high quality, high concentration lentiviral vectors from robust and scalable processes.
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Affiliation(s)
- Christopher Perry
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Gower St, London WC1E 6BT, UK;
- Division of Advanced Therapies, National Institute for Biological Standards and Control, South Mimms EN6 3QG, UK
| | - Andrea C. M. E. Rayat
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Gower St, London WC1E 6BT, UK;
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French AJ, Natesampillai S, Krogman A, Correia C, Peterson KL, Alto A, Chandrasekar AP, Misra A, Li Y, Kaufmann SH, Badley AD, Cummins NW. Reactivating latent HIV with PKC agonists induces resistance to apoptosis and is associated with phosphorylation and activation of BCL2. PLoS Pathog 2020; 16:e1008906. [PMID: 33075109 PMCID: PMC7595626 DOI: 10.1371/journal.ppat.1008906] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 10/29/2020] [Accepted: 08/20/2020] [Indexed: 02/07/2023] Open
Abstract
Eradication of HIV-1 by the "kick and kill" strategy requires reactivation of latent virus to cause death of infected cells by either HIV-induced or immune-mediated apoptosis. To date this strategy has been unsuccessful, possibly due to insufficient cell death in reactivated cells to effectively reduce HIV-1 reservoir size. As a possible cause for this cell death resistance, we examined whether leading latency reversal agents (LRAs) affected apoptosis sensitivity of CD4 T cells. Multiple LRAs of different classes inhibited apoptosis in CD4 T cells. Protein kinase C (PKC) agonists bryostatin-1 and prostratin induced phosphorylation and enhanced neutralizing capability of the anti-apoptotic protein BCL2 in a PKC-dependent manner, leading to resistance to apoptosis induced by both intrinsic and extrinsic death stimuli. Furthermore, HIV-1 producing CD4 T cells expressed more BCL2 than uninfected cells, both in vivo and after ex vivo reactivation. Therefore, activation of BCL2 likely contributes to HIV-1 persistence after latency reversal with PKC agonists. The effects of LRAs on apoptosis sensitivity should be considered in designing HIV cure strategies predicated upon the "kick and kill" paradigm.
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Affiliation(s)
- Andrea J. French
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Sekar Natesampillai
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Ashton Krogman
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Cristina Correia
- Division of Oncology Research, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Kevin L. Peterson
- Division of Oncology Research, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Alecia Alto
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Aswath P. Chandrasekar
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Anisha Misra
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Ying Li
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Scott H. Kaufmann
- Division of Oncology Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Andrew D. Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Nathan W. Cummins
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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8
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Monette A, Niu M, Chen L, Rao S, Gorelick RJ, Mouland AJ. Pan-retroviral Nucleocapsid-Mediated Phase Separation Regulates Genomic RNA Positioning and Trafficking. Cell Rep 2020; 31:107520. [PMID: 32320662 PMCID: PMC8965748 DOI: 10.1016/j.celrep.2020.03.084] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 02/12/2020] [Accepted: 03/24/2020] [Indexed: 02/07/2023] Open
Abstract
The duality of liquid-liquid phase separation (LLPS) of cellular components into membraneless organelles defines the nucleation of both normal and disease processes including stress granule (SG) assembly. From mounting evidence of LLPS utility by viruses, we discover that HIV-1 nucleocapsid (NC) protein condenses into zinc-finger (ZnF)-dependent LLPSs that are dynamically influenced by cytosolic factors. ZnF-dependent and Zinc (Zn2+)-chelation-sensitive NC-LLPS are formed in live cells. NC-Zn2+ ejection reverses the HIV-1 blockade on SG assembly, inhibits NC-SG assembly, disrupts NC/Gag-genomic RNA (vRNA) ribonucleoprotein complexes, and causes nuclear sequestration of NC and the vRNA, inhibiting Gag expression and virus release. NC ZnF mutagenesis eliminates the HIV-1 blockade of SG assembly and repositions vRNA to SGs. We find that NC-mediated, Zn2+-coordinated phase separation is conserved among diverse retrovirus subfamilies, illustrating that this exquisitely evolved Zn2+-dependent feature of virus replication represents a critical target for pan-antiretroviral therapies.
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Affiliation(s)
- Anne Monette
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
| | - Meijuan Niu
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, QC H3T 1E2, Canada
| | - Lois Chen
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, QC H3T 1E2, Canada; Department of Microbiology and Immunology, McGill University, Montréal, QC H3A 2B4, Canada
| | - Shringar Rao
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, QC H3T 1E2, Canada; Department of Biochemistry, Erasmus University Medical Center, Ee634, PO Box 2040, 3000CA Rotterdam, the Netherlands
| | - Robert James Gorelick
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA
| | - Andrew John Mouland
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, QC H3T 1E2, Canada; Department of Microbiology and Immunology, McGill University, Montréal, QC H3A 2B4, Canada; Department of Medicine, McGill University, Montréal, QC H3G 2M1, Canada.
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Paim AC, Badley AD, Cummins NW. Mechanisms of Human Immunodeficiency Virus-Associated Lymphocyte Regulated Cell Death. AIDS Res Hum Retroviruses 2020; 36:101-115. [PMID: 31659912 PMCID: PMC7044792 DOI: 10.1089/aid.2019.0213] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Human immunodeficiency virus-1 (HIV-1) causes CD4 T cell depletion through a number of mechanisms, including programmed cell death pathways (both apoptotic and nonapoptotic). In the setting of HIV-1 infection, the enhanced lymphocyte cell death occurs as a consequence of complex interactions between the host immune system and viral factors, which are reviewed herein. On the other hand, the main challenge to HIV-1 eradication is the development of latent infection in a subset of long lived cells, including CD4+ T cells and macrophages, which resist HIV-induced cell death. Understanding the potential mechanisms of how HIV-1 induces lymphocyte cell death is critical to the "kick and kill" cure strategy, which relies on the effective killing of reactivated, HIV-1-infected cells.
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Affiliation(s)
- Ana C. Paim
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota
| | - Andrew D. Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota
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Chandrasekar AP, Cummins NW, Badley AD. The Role of the BCL-2 Family of Proteins in HIV-1 Pathogenesis and Persistence. Clin Microbiol Rev 2019; 33:e00107-19. [PMID: 31666279 PMCID: PMC6822993 DOI: 10.1128/cmr.00107-19] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Advances in HIV-1 therapy have transformed the once fatal infection into a manageable, chronic condition, yet the search for a widely applicable approach to cure remains elusive. The ineffectiveness of antiretroviral therapy (ART) in reducing the size of the HIV-1 latent reservoir has prompted investigation into the mechanisms of HIV-1 latency and immune escape. One of the major regulators of apoptosis, the BCL-2 protein, alongside its homologous family members, is a major target of HIV-1-induced change. Recent studies have now demonstrated the association of this protein with cells that support proviral forms in the setting of latency and have helped identify BCL-2 as a novel and promising therapeutic target for HIV-1 therapy directed at possible cure. This review aims to systematically review the interactions of HIV-1 with BCL-2 and its homologs and to examine the possibility of using BCL-2 inhibitors in the study and elimination of the latent reservoir.
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Affiliation(s)
| | - Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, USA
| | - Andrew D Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, USA
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
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HIV Protease-Generated Casp8p41, When Bound and Inactivated by Bcl2, Is Degraded by the Proteasome. J Virol 2018; 92:JVI.00037-18. [PMID: 29643240 PMCID: PMC6002723 DOI: 10.1128/jvi.00037-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 04/02/2018] [Indexed: 11/20/2022] Open
Abstract
HIV protease is known to cause cell death, which is dependent upon cleavage of procaspase 8. HIV protease cleavage of procaspase 8 generates Casp8p41, which directly binds Bak with nanomolar affinity, causing Bak activation and consequent cell death. Casp8p41 can also bind Bcl2 with nanomolar affinity, in which case cell death is averted. Central memory CD4 T cells express high levels of Bcl2, possibly explaining why those cells do not die when they reactivate HIV. Here, we determine that the Casp8p41-Bcl2 complex is polyubiquitinated and degraded by the proteasome. Ixazomib, a proteasome inhibitor in clinical use, blocks this pathway, increasing the abundance of Casp8p41 and causing more cells to die in a Casp8p41-dependent manner. IMPORTANCE The Casp8p41 pathway of cell death is unique to HIV-infected cells yet is blocked by Bcl2. Once bound by Bcl2, Casp8p41 is polyubiquitinated and degraded by the proteasome. Proteasome inhibition blocks degradation of Casp8p41, increasing Casp8p41 levels and causing more HIV-infected cells to die.
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12
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Zhao RY. Yeast for virus research. MICROBIAL CELL (GRAZ, AUSTRIA) 2017; 4:311-330. [PMID: 29082230 PMCID: PMC5657823 DOI: 10.15698/mic2017.10.592] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/27/2017] [Indexed: 12/25/2022]
Abstract
Budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) are two popular model organisms for virus research. They are natural hosts for viruses as they carry their own indigenous viruses. Both yeasts have been used for studies of plant, animal and human viruses. Many positive sense (+) RNA viruses and some DNA viruses replicate with various levels in yeasts, thus allowing study of those viral activities during viral life cycle. Yeasts are single cell eukaryotic organisms. Hence, many of the fundamental cellular functions such as cell cycle regulation or programed cell death are highly conserved from yeasts to higher eukaryotes. Therefore, they are particularly suited to study the impact of those viral activities on related cellular activities during virus-host interactions. Yeasts present many unique advantages in virus research over high eukaryotes. Yeast cells are easy to maintain in the laboratory with relative short doubling time. They are non-biohazardous, genetically amendable with small genomes that permit genome-wide analysis of virologic and cellular functions. In this review, similarities and differences of these two yeasts are described. Studies of virologic activities such as viral translation, viral replication and genome-wide study of virus-cell interactions in yeasts are highlighted. Impacts of viral proteins on basic cellular functions such as cell cycle regulation and programed cell death are discussed. Potential applications of using yeasts as hosts to carry out functional analysis of small viral genome and to develop high throughput drug screening platform for the discovery of antiviral drugs are presented.
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Affiliation(s)
- Richard Yuqi Zhao
- Department of Pathology, Department of Microbiology and Immunology, Institute of Global Health, and Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Sampath R, Cummins NW, Natesampillai S, Bren GD, Chung TD, Baker J, Henry K, Pagliuzza A, Badley AD. Increasing procaspase 8 expression using repurposed drugs to induce HIV infected cell death in ex vivo patient cells. PLoS One 2017. [PMID: 28628632 PMCID: PMC5476266 DOI: 10.1371/journal.pone.0179327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
HIV persists because a reservoir of latently infected CD4 T cells do not express viral proteins and are indistinguishable from uninfected cells. One approach to HIV cure suggests that reactivating HIV will activate cytotoxic pathways; yet when tested in vivo, reactivating cells do not die sufficiently to reduce cell-associated HIV DNA levels. We recently showed that following reactivation from latency, HIV infected cells generate the HIV specific cytotoxic protein Casp8p41 which is produced by HIV protease cleaving procaspase 8. However, cell death is prevented, possibly due to low procaspase 8 expression. Here, we tested whether increasing procaspase 8 levels in CD4 T cells will produce more Casp8p41 following HIV reactivation, causing more reactivated cells to die. Screening 1277 FDA approved drugs identified 168 that increased procaspase 8 expression by at least 1.7-fold. Of these 30 were tested for anti-HIV effects in an acute HIVIIIb infection model, and 9 drugs at physiologic relevant levels significantly reduced cell-associated HIV DNA. Primary CD4 T cells from ART suppressed HIV patients were treated with one of these 9 drugs and reactivated with αCD3/αCD28. Four drugs significantly increased Casp8p41 levels following HIV reactivation, and decreased total cell associated HIV DNA levels (flurbiprofen: p = 0.014; doxycycline: p = 0.044; indomethacin: p = 0.025; bezafibrate: P = 0.018) without effecting the viability of uninfected cells. Thus procaspase 8 levels can be increased pharmacologically and, in the context of HIV reactivation, increase Casp8p41 causing death of reactivating cells and decreased HIV DNA levels. Future studies will be required to define the clinical utility of this or similar approaches.
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Affiliation(s)
- Rahul Sampath
- Division of Infectious Disease, Mayo Clinic Rochester, Rochester, MN, United States of America
| | - Nathan W. Cummins
- Division of Infectious Disease, Mayo Clinic Rochester, Rochester, MN, United States of America
| | - Sekar Natesampillai
- Division of Infectious Disease, Mayo Clinic Rochester, Rochester, MN, United States of America
| | - Gary D. Bren
- Division of Infectious Disease, Mayo Clinic Rochester, Rochester, MN, United States of America
| | - Thomas D. Chung
- Office of Translation to Practice, Mayo Clinic Rochester, Rochester, MN, United States of America
| | - Jason Baker
- Division of Infectious Diseases, University of Minnesota, Minneapolis, MN, United States of America
| | - Keith Henry
- HIV Program, Hennepin County Medical Center, Minnneapolis, MN, United States of America
| | - Amélie Pagliuzza
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Canada
| | - Andrew D. Badley
- Division of Infectious Disease, Mayo Clinic Rochester, Rochester, MN, United States of America
- Office of Translation to Practice, Mayo Clinic Rochester, Rochester, MN, United States of America
- * E-mail:
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Maintenance of the HIV Reservoir Is Antagonized by Selective BCL2 Inhibition. J Virol 2017; 91:JVI.00012-17. [PMID: 28331083 DOI: 10.1128/jvi.00012-17] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/17/2017] [Indexed: 11/20/2022] Open
Abstract
Decay of the HIV reservoir is slowed over time in part by expansion of the pool of HIV-infected cells. This expansion reflects homeostatic proliferation of infected cells by interleukin-7 (IL-7) or antigenic stimulation, as well as new rounds of infection of susceptible target cells. As novel therapies are being developed to accelerate the decay of the latent HIV reservoir, it will be important to identify interventions that prevent expansion and/or repopulation of the latent HIV reservoir. Our previous studies showed that HIV protease cleaves the host protein procaspase 8 to generate Casp8p41, which can bind and activate Bak to induce apoptosis of infected cells. In circumstances where expression of the anti-apoptotic protein BCL2 is high, Casp8p41 instead binds BCL2, and cell death does not occur. This effect can be overcome by treating cells with the clinically approved BCL2 antagonist venetoclax, which prevents Casp8p41 from binding BCL2, thereby allowing Casp8p41 to bind Bak and kill the infected cell. Here we assess whether the events that maintain the HIV reservoir are also antagonized by venetoclax. Using the J-Lat 10.6 model of persistent infection, we demonstrate that proliferation and HIV expression are countered by the use of venetoclax, which causes preferential killing of the HIV-expressing cells. Similarly, during new rounds of infection of primary CD4 T cells, venetoclax causes selective killing of HIV-infected cells, resulting in decreased numbers of HIV DNA-containing cells.IMPORTANCE Cure of HIV infection requires an intervention that reduces the HIV reservoir size. A variety of approaches are being tested for their ability to impact HIV reservoir size. Even if successful, however, these approaches will need to be combined with additional complementary approaches that prevent replenishment or repopulation of the HIV reservoir. Our previous studies have shown that the FDA-approved BCL2 antagonist venetoclax has a beneficial effect on the HIV reservoir size following HIV reactivation. Here we demonstrate that venetoclax also has a beneficial effect on HIV reservoir size in a model of homeostatic proliferation of HIV as well as in acute spreading infection of HIV in primary CD4 T cells. These results suggest that venetoclax, either alone or in combination with other approaches to reducing HIV reservoir size, is a compound worthy of further study for its effects on HIV reservoir size.
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Koçak Y, Özyer T, Alhajj R. Utilizing maximal frequent itemsets and social network analysis for HIV data analysis. J Cheminform 2016. [PMCID: PMC5395515 DOI: 10.1186/s13321-016-0184-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Acquired immune deficiency syndrome is a deadly disease which is caused by human immunodeficiency virus (HIV). This virus attacks patients immune system and effects its ability to fight against diseases. Developing effective medicine requires understanding the life cycle and replication ability of the virus. HIV-1 protease enzyme is used to cleave an octamer peptide into peptides which are used to create proteins by the virus. In this paper, a novel feature extraction method is proposed for understanding important patterns in octamer’s cleavability. This feature extraction method is based on data mining techniques which are used to find important relations inside a dataset by comprehensively analyzing the given data. As demonstrated in this paper, using the extracted information in the classification process yields important results which may be taken into consideration when developing a new medicine. We have used 746 and 1625, Impens and schilling data instances from the 746-dataset. Besides, we have performed social network analysis as a complementary alternative method.
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Sampath R, Cummins NW, Badley AD. Casp8p41: The Protean Mediator of Death in CD4 T-cells that Replicate HIV. J Cell Death 2016; 9:9-17. [PMID: 27721655 PMCID: PMC5040423 DOI: 10.4137/jcd.s39872] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/12/2016] [Accepted: 06/14/2016] [Indexed: 01/15/2023] Open
Abstract
HIV cure is now the focus of intense research after Timothy Ray Brown (the Berlin patient) set the precedent of being the first and only person cured. A major barrier to achieving this goal on a meaningful scale is an elimination of the latent reservoir, which is thought to comprise CD4-positive cells that harbor integrated, replication-competent HIV provirus. These cells do not express viral proteins, are indistinguishable from uninfected CD4 cells, and are thought to be responsible for HIV viral rebound—that occurs within weeks of combination anti retroviral therapy (cART) interruption. Modalities to engineer transcriptional stimulation (reactivation) of this dormant integrated HIV provirus, leading to expression of cytotoxic viral proteins, are thought to be a specific way to eradicate the latently infected CD4 pool and are becoming increasingly relevant in the era of HIV cure. HIV protease is one such protein produced after HIV reactivation that cleaves procaspase-8 to generate a novel protein Casp8p41. Casp8p41 then binds to the BH3 domain of BAK, leading to BAK oligomerization, mitochondrial depolarization, and apoptosis. In central memory T cells (TCMs) from HIV-infected patients, an elevated Bcl-2/procaspase-8 ratio was observed, and Casp8p41 binding to Bcl-2 was associated with a lack of reactivation-induced cell death. This was reversed by priming cells with a specific Bcl-2 antagonist prior to reactivation, resulting in increased cell death and decreased HIV DNA in a Casp8p41-dependent pathway. This review describes the biology, clinical relevance, and implications of Casp8p41 for a potential cure.
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Affiliation(s)
- Rahul Sampath
- Division of Infectious Diseases, Mayo Clinic, Rochester, MN, USA
| | - Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic, Rochester, MN, USA
| | - Andrew D Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester, MN, USA
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Affiliation(s)
- Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic Rochester, Rochester, MN, USA
| | - Andrew D Badley
- Division of Infectious Diseases, Mayo Clinic Rochester, Rochester, MN, USA
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Wen J, Yan M, Liu Y, Li J, Xie Y, Lu Y, Kamata M, Chen ISY. Specific Elimination of Latently HIV-1 Infected Cells Using HIV-1 Protease-Sensitive Toxin Nanocapsules. PLoS One 2016; 11:e0151572. [PMID: 27049645 PMCID: PMC4822841 DOI: 10.1371/journal.pone.0151572] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/01/2016] [Indexed: 12/21/2022] Open
Abstract
Anti-retroviral drugs suppress HIV-1 plasma viremia to undetectable levels; however, latent HIV-1 persists in reservoirs within HIV-1-infected patients. The silent provirus can be activated through the use of drugs, including protein kinase C activators and histone deacetylase inhibitors. This “shock” approach is then followed by “kill” of the producing cells either through direct HIV-1-induced cell death or natural immune mechanisms. However, these mechanisms are relatively slow and effectiveness is unclear. Here, we develop an approach to specifically target and kill cells that are activated early in the process of virus production. We utilize a novel nanocapsule technology whereby the ricin A chain is encapsulated in an inactive form within a polymer shell. Specificity for release of the ricin A toxin is conferred by peptide crosslinkers that are sensitive to cleavage by HIV-1 protease. By using well-established latent infection models, J-Lat and U1 cells, we demonstrate that only within an HIV-1-producing cell expressing functional HIV-1 protease will the nanocapsule release its ricin A cargo, shutting down viral and cellular protein synthesis, and ultimately leading to rapid death of the producer cell. Thus, we provide proof of principle for a novel technology to kill HIV-1-producing cells without effects on non-target cells.
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Affiliation(s)
- Jing Wen
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, University of California Los Angeles, Los Angeles, California, United States of America
| | - Ming Yan
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, University of California Los Angeles, Los Angeles, California, United States of America
| | - Yang Liu
- Department of Biomolecular and Chemical Engineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jie Li
- Department of Biomolecular and Chemical Engineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Yiming Xie
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, University of California Los Angeles, Los Angeles, California, United States of America
| | - Yunfeng Lu
- Department of Biomolecular and Chemical Engineering, University of California Los Angeles, Los Angeles, California, United States of America
- California NanoSystems Institute (CNSI), University of California Los Angeles, Los Angeles, California, United States of America
| | - Masakazu Kamata
- Division of Hematology-Oncology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (MK); (ISYC)
| | - Irvin S. Y. Chen
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, University of California Los Angeles, Los Angeles, California, United States of America
- UCLA AIDS Institute, Los Angeles, California, United States of America
- * E-mail: (MK); (ISYC)
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Manning T, Walsh P. The importance of physicochemical characteristics and nonlinear classifiers in determining HIV-1 protease specificity. Bioengineered 2016; 7:65-78. [PMID: 27212259 PMCID: PMC4879986 DOI: 10.1080/21655979.2016.1149271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/25/2016] [Accepted: 01/26/2016] [Indexed: 10/21/2022] Open
Abstract
This paper reviews recent research relating to the application of bioinformatics approaches to determining HIV-1 protease specificity, outlines outstanding issues, and presents a new approach to addressing these issues. Leading machine learning theory for the problem currently suggests that the direct encoding of the physicochemical properties of the amino acid substrates is not required for optimal performance. A number of amino acid encoding approaches which incorporate potentially relevant physicochemical properties of the substrate are identified, and are evaluated using a nonlinear task decomposition based neuroevolution algorithm. The results are evaluated, and compared against a recent benchmark set on a nonlinear classifier using only amino acid sequence and identity information. Ensembles of these nonlinear classifiers using the physicochemical properties of the substrate are demonstrated to consistently outperform the recently published state-of-the-art linear support vector machine based approach in out-of-sample evaluations.
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Affiliation(s)
- Timmy Manning
- Department of Computer Science, Cork Institute of Technology, Cork, Ireland
| | - Paul Walsh
- Department of Computer Science, Cork Institute of Technology, Cork, Ireland
- NSilico Ltd, Rubicon Innovation Center, Cork, Ireland
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20
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Cummins NW, Sainski AM, Dai H, Natesampillai S, Pang YP, Bren GD, de Araujo Correia MCM, Sampath R, Rizza SA, O'Brien D, Yao JD, Kaufmann SH, Badley AD. Prime, Shock, and Kill: Priming CD4 T Cells from HIV Patients with a BCL-2 Antagonist before HIV Reactivation Reduces HIV Reservoir Size. J Virol 2016; 90:4032-4048. [PMID: 26842479 PMCID: PMC4810548 DOI: 10.1128/jvi.03179-15] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/28/2016] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Understanding how some HIV-infected cells resist the cytotoxicity of HIV replication is crucial to enabling HIV cure efforts. HIV killing of CD4 T cells that replicate HIV can involve HIV protease-mediated cleavage of procaspase 8 to generate a fragment (Casp8p41) that directly binds and activates the mitochondrial proapoptotic protein BAK. Here, we demonstrate that Casp8p41 also binds with nanomolar affinity to the antiapoptotic protein Bcl-2, which sequesters Casp8p41 and prevents apoptosis. Further, we show that central memory CD4 T cells (TCM) from HIV-infected individuals have heightened expression of BCL-2 relative to procaspase 8, possibly explaining the persistence of HIV-infected TCMdespite generation of Casp8p41. Consistent with this hypothesis, the selective BCL-2 antagonist venetoclax induced minimal killing of uninfected CD4 T cells but markedly increased the death of CD4 T cells and diminished cell-associated HIV DNA when CD4 T cells from antiretroviral therapy (ART)-suppressed HIV patients were induced with αCD3/αCD28 to reactivate HIVex vivo Thus, priming CD4 T cells from ART suppressed HIV patients with a BCL-2 antagonist, followed by HIV reactivation, achieves reductions in cell-associated HIV DNA, whereas HIV reactivation alone does not. IMPORTANCE HIV infection is incurable due to a long-lived reservoir of HIV(+)memory CD4 T cells, and no clinically relevant interventions have been identified that reduce the number of these HIV DNA-containing cells. Since postintegration HIV replication can result in HIV protease generation of Casp8p41, which activates BAK, causing infected CD4 T cell death, we sought to determine whether this occurs in memory CD4 T cells. Here, we demonstrate that memory CD4 T cells can generate Casp8p41 and yet are intrinsically resistant to death induced by diverse stimuli, including Casp8p41. Furthermore, BCL-2 expression is relatively increased in these cells and directly binds and inhibits Casp8p41's proapoptotic effects. Antagonizing BCL-2 with venetoclax derepresses this antagonism, resulting in death, preferentially in HIV DNA containing cells, since only these cells generate Casp8p41. Thus, BCL-2 antagonism is a clinically relevant intervention with the potential to reduce HIV reservoir size in patients.
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Affiliation(s)
- Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, USA
| | - Amy M Sainski
- Department of Pharmacology, Mayo Clinic, Rochester, Minnesota, USA
| | - Haiming Dai
- Department of Pharmacology, Mayo Clinic, Rochester, Minnesota, USA
- Division of Oncology Research, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Yuan-Ping Pang
- Department of Pharmacology, Mayo Clinic, Rochester, Minnesota, USA
| | - Gary D Bren
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Rahul Sampath
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, USA
| | - Stacey A Rizza
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, USA
| | - Daniel O'Brien
- Department of Biostatistics, Mayo Clinic, Rochester, Minnesota, USA
| | - Joseph D Yao
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Scott H Kaufmann
- Department of Pharmacology, Mayo Clinic, Rochester, Minnesota, USA
- Division of Oncology Research, Mayo Clinic, Rochester, Minnesota, USA
| | - Andrew D Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, USA
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
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HIV-1 Protease in the Fission Yeast Schizosaccharomyces pombe. PLoS One 2016; 11:e0151286. [PMID: 26982200 PMCID: PMC4794156 DOI: 10.1371/journal.pone.0151286] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 02/25/2016] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND HIV-1 protease (PR) is an essential viral enzyme. Its primary function is to proteolyze the viral Gag-Pol polyprotein for production of viral enzymes and structural proteins and for maturation of infectious viral particles. Increasing evidence suggests that PR cleaves host cellular proteins. However, the nature of PR-host cellular protein interactions is elusive. This study aimed to develop a fission yeast (Schizosaccharomyces pombe) model system and to examine the possible interaction of HIV-1 PR with cellular proteins and its potential impact on cell proliferation and viability. RESULTS A fission yeast strain RE294 was created that carried a single integrated copy of the PR gene in its chromosome. The PR gene was expressed using an inducible nmt1 promoter so that PR-specific effects could be measured. HIV-1 PR from this system cleaved the same indigenous viral p6/MA protein substrate as it does in natural HIV-1 infections. HIV-1 PR expression in fission yeast cells prevented cell proliferation and induced cellular oxidative stress and changes in mitochondrial morphology that led to cell death. Both these PR activities can be prevented by a PR-specific enzymatic inhibitor, indinavir, suggesting that PR-mediated proteolytic activities and cytotoxic effects resulted from enzymatic activities of HIV-1 PR. Through genome-wide screening, a serine/threonine kinase, Hhp2, was identified that suppresses HIV-1 PR-induced protease cleavage and cell death in fission yeast and in mammalian cells, where it prevented PR-induced apoptosis and cleavage of caspase-3 and caspase-8. CONCLUSIONS This is the first report to show that HIV-1 protease is functional as an enzyme in fission yeast, and that it behaves in a similar manner as it does in HIV-1 infection. HIV-1 PR-induced cell death in fission yeast could potentially be used as an endpoint for mechanistic studies, and this system could be used for developing a high-throughput system for drug screenings.
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22
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Wagner RN, Reed JC, Chanda SK. HIV-1 protease cleaves the serine-threonine kinases RIPK1 and RIPK2. Retrovirology 2015; 12:74. [PMID: 26297639 PMCID: PMC4546280 DOI: 10.1186/s12977-015-0200-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 08/13/2015] [Indexed: 11/21/2022] Open
Abstract
Background HIV-1 protease (PR) is essential for viral infectivity as it cleaves Gag and Gag-Pol polyprotein precursors during viral maturation. Recent evidence suggests that cellular proteins can also be cleaved by PR, perhaps representing an important viral strategy to counter host defense mechanisms. Receptor-interacting protein kinase 1 (RIPK1) and RIPK2 belong to a family of serine/threonine kinases with conserved domain architecture and important functions in apoptosis, necrosis and innate immunity. Results We found that RIPK1 and RIPK2 but not other members of the RIP kinase family are cleaved by HIV-1 PR. In RIPK1, we identified a putative PR cleavage site; a mutation at this site rendered RIPK1 resistant to PR cleavage. RIPK1 and RIPK2 were cleaved during HIV-1 infection of T cell lines or primary activated CD4+ T cells. Interfering with the viral life cycle at different stages by the addition of specific inhibitors against RT, integrase, or PR, completely prevented RIPK1 and RIPK2 cleavage. Cleavage of RIPK1 disrupted RIPK1/RIPK3 complex formation and RIPK1-mediated induction of NF-kB. Conclusions These findings indicate that RIPK1 and RIPK2 are targets of HIV-1 PR activity during infection, and their inactivation may contribute to modulation of cell death and host defense pathways by HIV-1. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0200-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Roland N Wagner
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, USA. .,Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
| | - John C Reed
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, USA. .,Roche, Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland.
| | - Sumit K Chanda
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, USA.
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23
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Rögnvaldsson T, You L, Garwicz D. State of the art prediction of HIV-1 protease cleavage sites. Bioinformatics 2014; 31:1204-10. [PMID: 25504647 DOI: 10.1093/bioinformatics/btu810] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/04/2014] [Indexed: 02/01/2023] Open
Abstract
MOTIVATION Understanding the substrate specificity of human immunodeficiency virus (HIV)-1 protease is important when designing effective HIV-1 protease inhibitors. Furthermore, characterizing and predicting the cleavage profile of HIV-1 protease is essential to generate and test hypotheses of how HIV-1 affects proteins of the human host. Currently available tools for predicting cleavage by HIV-1 protease can be improved. RESULTS The linear support vector machine with orthogonal encoding is shown to be the best predictor for HIV-1 protease cleavage. It is considerably better than current publicly available predictor services. It is also found that schemes using physicochemical properties do not improve over the standard orthogonal encoding scheme. Some issues with the currently available data are discussed. AVAILABILITY AND IMPLEMENTATION The datasets used, which are the most important part, are available at the UCI Machine Learning Repository. The tools used are all standard and easily available. CONTACT thorsteinn.rognvaldsson@hh.se.
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Affiliation(s)
- Thorsteinn Rögnvaldsson
- CAISR, School of Information Science, Computer and Electrical Engineering, Halmstad University, Halmstad, Sweden and Division of Clinical Chemistry and Pharmacology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Liwen You
- CAISR, School of Information Science, Computer and Electrical Engineering, Halmstad University, Halmstad, Sweden and Division of Clinical Chemistry and Pharmacology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Daniel Garwicz
- CAISR, School of Information Science, Computer and Electrical Engineering, Halmstad University, Halmstad, Sweden and Division of Clinical Chemistry and Pharmacology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
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24
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Mbita Z, Hull R, Dlamini Z. Human immunodeficiency virus-1 (HIV-1)-mediated apoptosis: new therapeutic targets. Viruses 2014; 6:3181-227. [PMID: 25196285 PMCID: PMC4147692 DOI: 10.3390/v6083181] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 06/12/2014] [Accepted: 07/08/2014] [Indexed: 12/18/2022] Open
Abstract
HIV has posed a significant challenge due to the ability of the virus to both impair and evade the host’s immune system. One of the most important mechanisms it has employed to do so is the modulation of the host’s native apoptotic pathways and mechanisms. Viral proteins alter normal apoptotic signaling resulting in increased viral load and the formation of viral reservoirs which ultimately increase infectivity. Both the host’s pro- and anti-apoptotic responses are regulated by the interactions of viral proteins with cell surface receptors or apoptotic pathway components. This dynamic has led to the development of therapies aimed at altering the ability of the virus to modulate apoptotic pathways. These therapies are aimed at preventing or inhibiting viral infection, or treating viral associated pathologies. These drugs target both the viral proteins and the apoptotic pathways of the host. This review will examine the cell types targeted by HIV, the surface receptors exploited by the virus and the mechanisms whereby HIV encoded proteins influence the apoptotic pathways. The viral manipulation of the hosts’ cell type to evade the immune system, establish viral reservoirs and enhance viral proliferation will be reviewed. The pathologies associated with the ability of HIV to alter apoptotic signaling and the drugs and therapies currently under development that target the ability of apoptotic signaling within HIV infection will also be discussed.
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Affiliation(s)
- Zukile Mbita
- College of Agriculture and Environmental Sciences, University of South Africa, Florida Science Campus, C/o Christiaan de Wet and Pioneer Avenue P/Bag X6, Johannesburg 1710, South Africa.
| | - Rodney Hull
- College of Agriculture and Environmental Sciences, University of South Africa, Florida Science Campus, C/o Christiaan de Wet and Pioneer Avenue P/Bag X6, Johannesburg 1710, South Africa.
| | - Zodwa Dlamini
- College of Agriculture and Environmental Sciences, University of South Africa, Florida Science Campus, C/o Christiaan de Wet and Pioneer Avenue P/Bag X6, Johannesburg 1710, South Africa.
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25
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Cummins NW, Badley AD. Making sense of how HIV kills infected CD4 T cells: implications for HIV cure. MOLECULAR AND CELLULAR THERAPIES 2014; 2:20. [PMID: 26056587 PMCID: PMC4452072 DOI: 10.1186/2052-8426-2-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 06/16/2014] [Indexed: 02/07/2023]
Abstract
Defining how HIV does, and does not, kill the host CD4 T cell that it infects is of paramount importance in an era when research is approaching a cure for infection. Three mutually exclusive pathways can lead to the death of HIV-infected cells during the HIV life cycle, before, coincident and after HIV integration and consequently may affect viral replication. We discuss the molecular mechanism underlying these pathways, the evidence supporting their roles in vivo, and contemplate how understanding these pathways might inform novel approaches to promote viral cure of HIV.
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Affiliation(s)
- Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic, 200 - 1st Street SW, Rochester, MN 55905 USA
| | - Andrew D Badley
- Division of Infectious Diseases, Mayo Clinic, 200 - 1st Street SW, Rochester, MN 55905 USA
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26
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Cummins NW, Badley AD. Making sense of how HIV kills infected CD4 T cells: implications for HIV cure. MOLECULAR AND CELLULAR THERAPIES 2014; 2:20. [PMID: 26056587 PMCID: PMC4452072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 06/16/2014] [Indexed: 11/21/2023]
Abstract
Defining how HIV does, and does not, kill the host CD4 T cell that it infects is of paramount importance in an era when research is approaching a cure for infection. Three mutually exclusive pathways can lead to the death of HIV-infected cells during the HIV life cycle, before, coincident and after HIV integration and consequently may affect viral replication. We discuss the molecular mechanism underlying these pathways, the evidence supporting their roles in vivo, and contemplate how understanding these pathways might inform novel approaches to promote viral cure of HIV.
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Affiliation(s)
- Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic, 200 - 1st Street SW, Rochester, MN 55905 USA
| | - Andrew D Badley
- Division of Infectious Diseases, Mayo Clinic, 200 - 1st Street SW, Rochester, MN 55905 USA
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27
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Rumlová M, Křížová I, Keprová A, Hadravová R, Doležal M, Strohalmová K, Pichová I, Hájek M, Ruml T. HIV-1 protease-induced apoptosis. Retrovirology 2014; 11:37. [PMID: 24886575 PMCID: PMC4229777 DOI: 10.1186/1742-4690-11-37] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 04/30/2014] [Indexed: 01/12/2023] Open
Abstract
Background Apoptosis is one of the presumptive causes of CD4+ T cell depletion during HIV infection and progression to AIDS. However, the precise role of HIV-1 in this process remains unexplained. HIV-1 protease (PR) has been suggested as a possible factor, but a direct link between HIV-1 PR enzymatic activity and apoptosis has not been established. Results Here, we show that expression of active HIV-1 PR induces death in HeLa and HEK-293 cells via the mitochondrial apoptotic pathway. This conclusion is based on in vivo observations of the direct localization of HIV-1 PR in mitochondria, a key player in triggering apoptosis. Moreover, we observed an HIV-1 PR concentration-dependent decrease in mitochondrial membrane potential and the role of HIV-1 PR in activation of caspase 9, PARP cleavage and DNA fragmentation. In addition, in vitro data demonstrated that HIV-1 PR mediates cleavage of mitochondrial proteins Tom22, VDAC and ANT, leading to release of AIF and Hsp60 proteins. By using yeast two-hybrid screening, we also identified a new HIV-1 PR interaction partner, breast carcinoma-associated protein 3 (BCA3). We found that BCA3 accelerates p53 transcriptional activity on the bax promoter, thus elevating the cellular level of pro-apoptotic Bax protein. Conclusion In summary, our results describe the involvement of HIV-1 PR in apoptosis, which is caused either by a direct effect of HIV-1 PR on mitochondrial membrane integrity or by its interaction with cellular protein BCA3.
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Affiliation(s)
- Michaela Rumlová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v,v,i,, IOCB & Gilead Research Center, Flemingovo nám, 2, 166 10 Prague, Czech Republic.
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28
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Cummins NW, Neuhaus J, Sainski AM, Strausbauch MA, Wettstein PJ, Lewin SR, Plana M, Rizza SA, Temesgen Z, Touloumi G, Freiberg M, Neaton J, Badley AD. Short communication: CD4 T cell declines occurring during suppressive antiretroviral therapy reflect continued production of Casp8p41. AIDS Res Hum Retroviruses 2014; 30:476-9. [PMID: 24344953 DOI: 10.1089/aid.2013.0243] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Most patients on suppressive antiretroviral therapy (ART) experience improvements in CD4 T cell count. However, some patients with undetectable viral load continue to lose CD4 T cells for unknown reasons. Casp8p41 is a host-derived protein fragment that is present only in productively infected cells and that causes the death of HIV-infected cells. We questioned whether ongoing CD4(+) T cell losses while on suppressive ART were associated with subclinical HIV replication causing production of Casp8p41. We analyzed the association of Casp8p41 content with subsequent CD4 losses in patients on continuous suppressive ART and in patients who discontinued ART after Casp8p41 content was determined, adjusting for age, baseline CD4(+) T cell count, and baseline HIV RNA level. Casp8p41 expression in memory CD4(+) T cells was measured by intracellular flow cytometry and was correlated with viral load and CD4(+) T cell change over time. In patients who stopped therapy after Casp8p41 content was determined, baseline Casp8p41 content did not predict CD4(+) T cell change. However, in patients on continuous ART, higher baseline Casp8p41 content was associated with a greater odds of a CD4(+) T cell decline at 6 months (p=0.01). Therefore, patients on suppressive ART, who have ongoing production of Casp8p41, have an increased risk of CD4 T cell losses, suggesting that subclinical HIV replication is driving both Casp8p41, which in turn causes a CD4(+) T cell decline.
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Affiliation(s)
| | - Jacqueline Neuhaus
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota
| | - Amy M. Sainski
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | | | - Peter J. Wettstein
- Departments of Surgery and Immunology, Mayo Clinic, Rochester, Minnesota
| | - Sharon R. Lewin
- Department of Infectious Diseases, Monash University, Melbourne, Victoria, Australia
- Infectious Diseases Unit, Alfred Hospital, Melbourne, Victoria, Australia
- Burnet Institute, Melbourne, Victoria, Australia
| | - Montserrat Plana
- Hospital Clinic-HIVACAT, IDIBAPS, University of Barcelona, Barcelona, Spain
| | - Stacey A. Rizza
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota
| | - Zelalem Temesgen
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota
| | - Giota Touloumi
- Department of Hygiene, Epidemiology and Medical Statistics, Athens University Medical School, Athens, Greece
| | - Matthew Freiberg
- Department of Infectious Diseases, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - James Neaton
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota
| | - Andrew D. Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota
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Cummins NW, Sainski AM, Natesampillai S, Bren GD, Badley AD. Choice of antiretroviral therapy differentially impacts survival of HIV-infected CD4 T cells. MOLECULAR AND CELLULAR THERAPIES 2014; 2:1. [PMID: 26057236 PMCID: PMC4448955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/29/2013] [Indexed: 11/21/2023]
Abstract
BACKGROUND HIV eradication strategies are now being evaluated in vitro and in vivo. A cornerstone of such approaches is maximal suppression of viral replication with combination antiretroviral therapy (ART). Since many antiretroviral agents have off target effects, and different classes target different components of the viral life cycle, we questioned whether different classes of ART might differentially affect the survival and persistence of productively HIV-infected CD4 T cells. METHODS In vitro infections of primary CD4 T cells using clinical isolates of HIV-1 that were either protease inhibitor susceptible (HIV PI-S), or resistant (HIV PI-R) were treated with nothing, lopinavir, efavirenz or raltegravir. Cell viability, apoptosis, and the proportion of surviving cells that were P24 positive was assessed by flow cytometry. RESULTS In HIV PI-S infected primary cultures, all three antiretroviral agents decreased viral replication, and reduced the total number of cells that were undergoing apoptosis (P < 0.01) similarly. Similarly, in the HIV PI-R infected cultures, both efavirenz and raltegravir reduced viral replication and reduced apoptosis compared to untreated control (P < 0.01), while lopinavir did not, suggesting that HIV replication drives T cell apoptosis, which was confirmed by association by linear regression (P < 0.0001) . However since HIV protease has been suggested to directly induce apoptosis of infected CD4 T cells, and HIV PI are intrinsically antiapoptotic, we evaluated apoptosis in productively infected (HIV P24+) cells. More HIV p24 positive cells were apoptotic in the Efavirenz or raltegravir treated cultures than the lopinavir treated cultures (P = 0.0008 for HIV PI-R and P = 0.06 for the HIV PI-S), indicating that drug class impacts survival of productively infected CD4 T cells. CONCLUSIONS Inhibiting HIV replication with a PI, NNRTI or INSTI reduces total HIV-induced T cell apoptosis. However, blocking HIV replication with PI but not with NNRTI or INSTI promotes survival of productively HIV-infected cells. Thus, selection of antiretroviral agents may impact the success of HIV eradication strategies.
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Affiliation(s)
- Nathan W Cummins
- />Division of Infectious Diseases, Mayo Clinic Rochester, Rochester, MN USA
| | - Amy M Sainski
- />Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic Rochester, Rochester, MN USA
| | | | - Gary D Bren
- />Division of Infectious Diseases, Mayo Clinic Rochester, Rochester, MN USA
| | - Andrew D Badley
- />Division of Infectious Diseases, Mayo Clinic Rochester, Rochester, MN USA
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Cummins NW, Sainski AM, Natesampillai S, Bren GD, Badley AD. Choice of antiretroviral therapy differentially impacts survival of HIV-infected CD4 T cells. MOLECULAR AND CELLULAR THERAPIES 2014; 2:1. [PMID: 26057236 PMCID: PMC4448955 DOI: 10.1186/2052-8426-2-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/29/2013] [Indexed: 01/04/2023]
Abstract
Background HIV eradication strategies are now being evaluated in vitro and in vivo. A cornerstone of such approaches is maximal suppression of viral replication with combination antiretroviral therapy (ART). Since many antiretroviral agents have off target effects, and different classes target different components of the viral life cycle, we questioned whether different classes of ART might differentially affect the survival and persistence of productively HIV-infected CD4 T cells. Methods In vitro infections of primary CD4 T cells using clinical isolates of HIV-1 that were either protease inhibitor susceptible (HIV PI-S), or resistant (HIV PI-R) were treated with nothing, lopinavir, efavirenz or raltegravir. Cell viability, apoptosis, and the proportion of surviving cells that were P24 positive was assessed by flow cytometry. Results In HIV PI-S infected primary cultures, all three antiretroviral agents decreased viral replication, and reduced the total number of cells that were undergoing apoptosis (P < 0.01) similarly. Similarly, in the HIV PI-R infected cultures, both efavirenz and raltegravir reduced viral replication and reduced apoptosis compared to untreated control (P < 0.01), while lopinavir did not, suggesting that HIV replication drives T cell apoptosis, which was confirmed by association by linear regression (P < 0.0001) . However since HIV protease has been suggested to directly induce apoptosis of infected CD4 T cells, and HIV PI are intrinsically antiapoptotic, we evaluated apoptosis in productively infected (HIV P24+) cells. More HIV p24 positive cells were apoptotic in the Efavirenz or raltegravir treated cultures than the lopinavir treated cultures (P = 0.0008 for HIV PI-R and P = 0.06 for the HIV PI-S), indicating that drug class impacts survival of productively infected CD4 T cells. Conclusions Inhibiting HIV replication with a PI, NNRTI or INSTI reduces total HIV-induced T cell apoptosis. However, blocking HIV replication with PI but not with NNRTI or INSTI promotes survival of productively HIV-infected cells. Thus, selection of antiretroviral agents may impact the success of HIV eradication strategies. Electronic supplementary material The online version of this article (doi:10.1186/2052-8426-2-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic Rochester, Rochester, MN USA
| | - Amy M Sainski
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic Rochester, Rochester, MN USA
| | | | - Gary D Bren
- Division of Infectious Diseases, Mayo Clinic Rochester, Rochester, MN USA
| | - Andrew D Badley
- Division of Infectious Diseases, Mayo Clinic Rochester, Rochester, MN USA
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Ouellet DL, Vigneault-Edwards J, Létourneau K, Gobeil LA, Plante I, Burnett JC, Rossi JJ, Provost P. Regulation of host gene expression by HIV-1 TAR microRNAs. Retrovirology 2013; 10:86. [PMID: 23938024 PMCID: PMC3751525 DOI: 10.1186/1742-4690-10-86] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 08/06/2013] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The transactivating response (TAR) element of human immunodeficiency virus type 1 (HIV-1) is the source of two functional microRNAs (miRNAs), miR-TAR-5p and miR-TAR-3p. The objective of this study was to characterize the post-transcriptional regulation of host messenger RNAs (mRNAs) relevant to HIV-1 pathogenesis by HIV-1 TAR miRNAs. RESULTS We demonstrated that TAR miRNAs derived from HIV-1 can incorporate into host effector Argonaute protein complexes, which is required if these miRNAs are to regulate host mRNA expression. Bioinformatic predictions and reporter gene activity assays identified regulatory elements complementary and responsive to miR-TAR-5p and miR-TAR-3p in the 3' untranslated region (UTR) of several candidate genes involved in apoptosis and cell survival. These include Caspase 8, Aiolos, Ikaros and Nucleophosmin (NPM)/B23. Analyses of Jurkat cells that stably expressed HIV-1 TAR or contained a full-length latent HIV provirus suggested that HIV-1 TAR miRNAs could regulate the expression of genes in T cells that affect the balance between apoptosis and cell survival. CONCLUSIONS HIV-1 TAR miRNAs may contribute to the replication cycle and pathogenesis of HIV-1, by regulating host genes involved in the intricate balance between apoptosis and infected cell, to induce conditions that promote HIV-1 propagation and survival.
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Affiliation(s)
- Dominique L Ouellet
- Department of Molecular and Cellular Biology, Beckman Research Institute at City of Hope, 1500 E Duarte Road, Duarte, CA 91010, USA
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Badley AD, Sainski A, Wightman F, Lewin SR. Altering cell death pathways as an approach to cure HIV infection. Cell Death Dis 2013; 4:e718. [PMID: 23846220 PMCID: PMC3730421 DOI: 10.1038/cddis.2013.248] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 05/22/2013] [Accepted: 05/29/2013] [Indexed: 12/13/2022]
Abstract
Recent cases of successful control of human immunodeficiency virus (HIV) by bone marrow transplant in combination with suppressive antiretroviral therapy (ART) and very early initiation of ART have provided proof of concept that HIV infection might now be cured. Current efforts focusing on gene therapy, boosting HIV-specific immunity, reducing inflammation and activation of latency have all been the subject of recent excellent reviews. We now propose an additional avenue of research towards a cure for HIV: targeting HIV apoptosis regulatory pathways. The central enigma of HIV disease is that HIV infection kills most of the CD4 T cells that it infects, but those cells that are spared subsequently become a latent reservoir for HIV against which current medications are ineffective. We propose that if strategies could be devised which would favor the death of all cells which HIV infects, or if all latently infected cells that release HIV would succumb to viral-induced cytotoxicity, then these approaches combined with effective ART to prevent spreading infection, would together result in a cure for HIV. This premise is supported by observations in other viral systems where the relationship between productive infection, apoptosis resistance, and the development of latency or persistence has been established. Therefore we propose that research focused at understanding the mechanisms by which HIV induces apoptosis of infected cells, and ways that some cells escape the pro-apoptotic effects of productive HIV infection are critical to devising novel and rational approaches to cure HIV infection.
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Affiliation(s)
- A D Badley
- Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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Segura MM, Mangion M, Gaillet B, Garnier A. New developments in lentiviral vector design, production and purification. Expert Opin Biol Ther 2013; 13:987-1011. [PMID: 23590247 DOI: 10.1517/14712598.2013.779249] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Lentiviruses are a very potent class of viral vectors for which there is presently a rapidly growing interest for a number of gene therapy. However, their construction, production and purification need to be performed according to state-of-the-art techniques in order to obtain sufficient quantities of high purity material of any usefulness and safety. AREAS COVERED The recent advances in the field of recombinant lentivirus vector design, production and purification will be reviewed with an eye toward its utilization for gene therapy. Such a review should be helpful for the potential user of this technology. EXPERT OPINION The principal hurdles toward the use of recombinant lentivirus as a gene therapy vector are the low titer at which it is produced as well as the difficulty to purify it at an acceptable level without degrading it. The recent advances in the bioproduction of this vector suggest these issues are about to be resolved, making the retrovirus gene therapy a mature technology.
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Affiliation(s)
- Maria Mercedes Segura
- Chemical Engineering Department, Universitat Autònoma de Barcelona, Campus Bellaterra, Cerdanyola del Vallès (08193), Barcelona, Spain
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Abstract
Since the initial description of apoptosis, a number of different forms of cell death have been described. In this review we will focus on classic caspase-dependent apoptosis and its variations that contribute to diseases. Over fifty years of research have clarified molecular mechanisms involved in apoptotic signaling as well and shown that alterations of these pathways lead to human diseases. Indeed both reduced and increased apoptosis can result in pathology. More recently these findings have led to the development of therapeutic approaches based on regulation of apoptosis, some of which are in clinical trials or have entered medical practice.
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Affiliation(s)
- Bartolo Favaloro
- Dipartimento di Scienze Biomediche, Universita' "G. d'Annunzio" Chieti-Pescara, Italy
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Yang H, Nkeze J, Zhao RY. Effects of HIV-1 protease on cellular functions and their potential applications in antiretroviral therapy. Cell Biosci 2012; 2:32. [PMID: 22971934 PMCID: PMC3490751 DOI: 10.1186/2045-3701-2-32] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 08/31/2012] [Indexed: 11/10/2022] Open
Abstract
Human Immunodeficiency Virus Type 1 (HIV-1) protease inhibitors (PIs) are the most potent class of drugs in antiretroviral therapies. However, viral drug resistance to PIs could emerge rapidly thus reducing the effectiveness of those drugs. Of note, all current FDA-approved PIs are competitive inhibitors, i.e., inhibitors that compete with substrates for the active enzymatic site. This common inhibitory approach increases the likelihood of developing drug resistant HIV-1 strains that are resistant to many or all current PIs. Hence, new PIs that move away from the current target of the active enzymatic site are needed. Specifically, allosteric inhibitors, inhibitors that prohibit PR enzymatic activities through non-competitive binding to PR, should be sought. Another common feature of current PIs is they were all developed based on the structure-based design. Drugs derived from a structure-based strategy may generate target specific and potent inhibitors. However, this type of drug design can only target one site at a time and drugs discovered by this method are often associated with strong side effects such as cellular toxicity, limiting its number of target choices, efficacy, and applicability. In contrast, a cell-based system may provide a useful alternative strategy that can overcome many of the inherited shortcomings associated with structure-based drug designs. For example, allosteric PIs can be sought using a cell-based system without considering the site or mechanism of inhibition. In addition, a cell-based system can eliminate those PIs that have strong cytotoxic effect. Most importantly, a simple, economical, and easy-to-maintained eukaryotic cellular system such as yeast will allow us to search for potential PIs in a large-scaled high throughput screening (HTS) system, thus increasing the chances of success. Based on our many years of experience in using fission yeast as a model system to study HIV-1 Vpr, we propose the use of fission yeast as a possible surrogate system to study the effects of HIV-1 protease on cellular functions and to explore its utility as a HTS system to search for new PIs to battle HIV-1 resistant strains.
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Affiliation(s)
- Hailiu Yang
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA.
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36
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Schnepple DJ, Shepard B, Bren GD, Cummins NW, Natesampillai S, Trushin S, Algeciras-Schimnich A, Meng XW, Sainski AM, Rizza SA, Kaufmann SH, Badley AD. Isolation of a TRAIL antagonist from the serum of HIV-infected patients. J Biol Chem 2011; 286:35742-35754. [PMID: 21859711 DOI: 10.1074/jbc.m111.274639] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Virus-host interactions are characterized by the selection of adaptive mechanisms by which to evade pathogenic and defense mechanisms, respectively. In primary T cells infected with HIV, HIV infection up-regulates TNF-related apoptosis inducing ligand (TRAIL) and death-inducing TRAIL receptors, but blockade of TRAIL:TRAIL receptor interaction does not alter HIV-induced cell death. Instead, HIV infection results in a novel splice variant that we call TRAIL-short (TRAIL-s), which antagonizes TRAIL-R2. In HIV patients, plasma TRAIL-s concentration increases with increasing viral load and renders cells resistant to TRAIL-induced death. Knockdown of TRAIL-s abrogates this resistance. We propose that TRAIL-s is a novel adaptive mechanism of apoptosis resistance acquired by HIV-infected cells to avoid their elimination by TRAIL-dependent effector mechanism.
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Affiliation(s)
- David J Schnepple
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Program in Molecular Neuroscience, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Brett Shepard
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Gary D Bren
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Program in Translational Immunovirology and Biodefense, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Sekar Natesampillai
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Sergey Trushin
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | | | - Xue W Meng
- Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Amy M Sainski
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Molecular Pharmacology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Stacey A Rizza
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Scott H Kaufmann
- Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Department of Molecular Pharmacology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Andrew D Badley
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota 55905; Program in Translational Immunovirology and Biodefense, Mayo Clinic College of Medicine, Rochester, Minnesota 55905.
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Nie Z, Bren GD, Rizza SA, Badley AD. HIV Protease Cleavage of Procaspase 8 is Necessary for Death of HIV-Infected Cells. Open Virol J 2011; 2:1-7. [PMID: 18818774 PMCID: PMC2548307 DOI: 10.2174/1874357900802010001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Numerous host and viral factors are capable of causing death of HIV infected cells, uninfected bystander cells, or both. We assessed the relevance of HIV protease in infected cell killing by mutating its obligate substrate for death, procaspase 8. VSV pseudotyped HIV infection of cells expressing WT caspase 8 resulted in apoptotic cell death and generation of the HIV protease specific cleavage product of procaspase 8, casp8p41. Conversely, both cell death and casp8p41 production were inhibited in cells expressing procaspase 8 engineered to be resistant to HIV protease cleavage. Lymph nodes from HIV-infected patients with ongoing viral replication also selectively expressed casp8p41, which colocalized with both infected and apoptotic cells. HIV protease cleavage of procaspase 8 appears to be a necessary event for infected cell killing, which is responsible for infected cell death within lymphoid tissues from HIV-infected patients.
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Affiliation(s)
- Zilin Nie
- Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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38
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The HIV-1-specific protein Casp8p41 induces death of infected cells through Bax/Bak. J Virol 2011; 85:7965-75. [PMID: 21653671 DOI: 10.1128/jvi.02515-10] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Casp8p41, a novel protein generated when HIV-1 protease cleaves caspase 8, independently causes NF-κB activation, proinflammatory cytokine production, and cell death. Here we investigate the mechanism by which Casp8p41 induces cell death. Immunogold staining and electron microscopy demonstrate that Casp8p41 localizes to mitochondria of activated primary CD4 T cells, suggesting mitochondrial involvement. Therefore, we assessed the dependency of Casp8p41-induced death on Bax/Bak and caspase 9. In wild-type (WT) mouse embryonic fibroblast (MEF) cells, Casp8p41 causes rapid mitochondrial depolarization (P < 0.001), yet Casp8p41 expression in Bax/Bak double-knockout (DKO) MEF cells does not. Similarly, caspase 9-deficient T cells (JMR cells), which express Casp8p41, undergo minimal cell death, whereas reconstituting these cells with caspase 9 (F9 cells) restores Casp8p41 cytotoxicity (P < 0.01). The infection of caspase 9-deficient cells with a green fluorescent protein (GFP) HIV-1 reporter virus results in cell death in 32% of infected GFP-positive cells, while the restoration of caspase 9 expression in these cells restores infected-cell killing to 68% (P < 0.05), with similar levels of viral replication between infections. Our data demonstrate that Casp8p41 requires Bax/Bak to induce mitochondrial depolarization, which leads to caspase 9 activation following either Casp8p41 expression or HIV-1 infection. This understanding allows the design of strategies to interrupt this form of death of HIV-1-infected cells.
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Février M, Dorgham K, Rebollo A. CD4+ T cell depletion in human immunodeficiency virus (HIV) infection: role of apoptosis. Viruses 2011; 3:586-612. [PMID: 21994747 PMCID: PMC3185763 DOI: 10.3390/v3050586] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/03/2011] [Accepted: 05/04/2011] [Indexed: 02/07/2023] Open
Abstract
Human immunodeficiency virus (HIV) infection is principally a mucosal disease and the gastrointestinal (GI) tract is the major site of HIV replication. Loss of CD4+ T cells and systemic immune hyperactivation are the hallmarks of HIV infection. The end of acute infection is associated with the emergence of specific CD4+ and CD8+ T cell responses and the establishment of a chronic phase of infection. Abnormal levels of immune activation and inflammation persist despite a low steady state level of viremia. Although the causes of persistent immune hyperactivation remain incompletely characterized, physiological alterations of gastrointestinal tract probably play a major role. Failure to restore Th17 cells in gut-associated lymphoid tissues (GALT) might impair the recovery of the gut mucosal barrier. This review discusses recent advances on understanding the contribution of CD4+ T cell depletion to HIV pathogenesis.
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Affiliation(s)
- Michèle Février
- Unité Génomique Virale et Vaccination, CNRS URA3015, Institut Pasteur, 28 rue du Dr Roux, 75015 Paris, France.
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40
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Natesampillai S, Nie Z, Cummins NW, Jochmans D, Bren GD, Angel JB, Badley AD. Patients with discordant responses to antiretroviral therapy have impaired killing of HIV-infected T cells. PLoS Pathog 2010; 6:e1001213. [PMID: 21124822 PMCID: PMC2991267 DOI: 10.1371/journal.ppat.1001213] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 10/27/2010] [Indexed: 11/18/2022] Open
Abstract
In medicine, understanding the pathophysiologic basis of exceptional circumstances has led to an enhanced understanding of biology. We have studied the circumstance of HIV-infected patients in whom antiretroviral therapy results in immunologic benefit, despite virologic failure. In such patients, two protease mutations, I54V and V82A, occur more frequently. Expressing HIV protease containing these mutations resulted in less cell death, caspase activation, and nuclear fragmentation than wild type (WT) HIV protease or HIV protease containing other mutations. The impaired induction of cell death was also associated with impaired cleavage of procaspase 8, a requisite event for HIV protease mediated cell death. Primary CD4 T cells expressing I54V or V82A protease underwent less cell death than with WT or other mutant proteases. Human T cells infected with HIV containing these mutations underwent less cell death and less Casp8p41 production than WT or HIV containing other protease mutations, despite similar degrees of viral replication. The reductions in cell death occurred both within infected cells, as well as in uninfected bystander cells. These data indicate that single point mutations within HIV protease which are selected in vivo can significantly impact the ability of HIV to kill CD4 T cells, while not impacting viral replication. Therefore, HIV protease regulates both HIV replication as well as HIV induced T cell depletion, the hallmark of HIV pathogenesis. Although most patients infected with HIV who have persistent viral replication will experience a decline in CD4 T cell number, this is not always the case. In a small subset of patients in whom ART fails to suppress viral replication, CD4 T cell counts do not fall, for unknown reasons. We identified that these patients have an increased frequency of selected protease mutations, which we call discordance associated mutations (DAMs). While wild type protease rapidly induces cell death, protease containing DAMs have an impaired ability to induce cell death, due to a selective defect in cleavage of caspase 8. Furthermore, viruses containing DAMs replicate as efficiently as wild type, yet fail to induce infected cell death. These results demonstrate an unanticipated role of protease in determining the immunologic outcome of HIV infection in vitro and in vivo.
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Affiliation(s)
- Sekar Natesampillai
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Zilin Nie
- University of Michigan, Ann Arbor, Michigan, United States of America
| | - Nathan W. Cummins
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | | | - Gary D. Bren
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | | | - Andrew D. Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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Lambert AA, Imbeault M, Gilbert C, Tremblay MJ. HIV-1 induces DCIR expression in CD4+ T cells. PLoS Pathog 2010; 6:e1001188. [PMID: 21085612 PMCID: PMC2978727 DOI: 10.1371/journal.ppat.1001188] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 10/12/2010] [Indexed: 01/30/2023] Open
Abstract
The C-type lectin receptor DCIR, which has been shown very recently to act as an attachment factor for HIV-1 in dendritic cells, is expressed predominantly on antigen-presenting cells. However, this concept was recently challenged by the discovery that DCIR can also be detected in CD4+ T cells found in the synovial tissue from rheumatoid arthritis (RA) patients. Given that RA and HIV-1 infections share common features such as a chronic inflammatory condition and polyclonal immune hyperactivation status, we hypothesized that HIV-1 could promote DCIR expression in CD4+ T cells. We report here that HIV-1 drives DCIR expression in human primary CD4+ T cells isolated from patients (from both aviremic/treated and viremic/treatment naive persons) and cells acutely infected in vitro (seen in both virus-infected and uninfected cells). Soluble factors produced by virus-infected cells are responsible for the noticed DCIR up-regulation on uninfected cells. Infection studies with Vpr- or Nef-deleted viruses revealed that these two viral genes are not contributing to the mechanism of DCIR induction that is seen following acute infection of CD4+ T cells with HIV-1. Moreover, we report that DCIR is linked to caspase-dependent (induced by a mitochondria-mediated generation of free radicals) and -independent intrinsic apoptotic pathways (involving the death effector AIF). Finally, we demonstrate that the higher surface expression of DCIR in CD4+ T cells is accompanied by an enhancement of virus attachment/entry, replication and transfer. This study shows for the first time that HIV-1 induces DCIR membrane expression in CD4+ T cells, a process that might promote virus dissemination throughout the infected organism. The type II transmembrane protein DCIR belongs to the C-type lectin domain family receptor and is predominantly expressed in cells of the myeloid lineage. However recent evidence suggests that it can also be induced in CD4+ T cells placed under an inflammatory condition. We assessed the capacity of HIV-1 to promote DCIR expression in CD4+ T cells because the establishment of an inflammatory state is a hallmark of this retroviral infection in humans. We report here that a higher DCIR expression is detected not only in CD4+ T cells acutely infected with HIV-1 in vitro but also in clinical cell samples. Additional studies suggest a possible link between DCIR induction and apoptosis through both caspase-dependent and -independent intrinsic pathways. The greater expression of DCIR on the surface of CD4+ T cells results in more efficient virus attachment/entry, replication and transfer processes.
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Affiliation(s)
| | | | - Caroline Gilbert
- Centre Hospitalier Universitaire de Québec-CHUL, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Université Laval, Québec, Canada
- * E-mail: (MJT); (CG)
| | - Michel J. Tremblay
- Centre Hospitalier Universitaire de Québec-CHUL, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Université Laval, Québec, Canada
- * E-mail: (MJT); (CG)
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Abstract
The inevitable decline of CD4T cells in untreated infection with the Human immunodeficiency virus (HIV) is due in large part to apoptosis, one type of programmed cell death. There is accumulating evidence that the accelerated apoptosis of CD4T cells in HIV infection is multifactorial, with direct viral cytotoxicity, signaling events triggered by viral proteins and aberrant immune activation adding to normal immune defense mechanisms to contribute to this phenomenon. Current antiviral treatment strategies generally lead to reduced apoptosis, but this approach may come at the cost of preserving latent viral reservoirs. It is the purpose of this review to provide an update on the current understanding of the role and mechanisms of accelerated apoptosis of T cells in the immunopathogenesis of HIV infection, and to highlight potential ways in which this seemingly deleterious process could be harnessed to not just control, but treat HIV infection.
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43
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Toxin-based therapeutic approaches. Toxins (Basel) 2010; 2:2519-83. [PMID: 22069564 PMCID: PMC3153180 DOI: 10.3390/toxins2112519] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 10/25/2010] [Accepted: 10/26/2010] [Indexed: 01/08/2023] Open
Abstract
Protein toxins confer a defense against predation/grazing or a superior pathogenic competence upon the producing organism. Such toxins have been perfected through evolution in poisonous animals/plants and pathogenic bacteria. Over the past five decades, a lot of effort has been invested in studying their mechanism of action, the way they contribute to pathogenicity and in the development of antidotes that neutralize their action. In parallel, many research groups turned to explore the pharmaceutical potential of such toxins when they are used to efficiently impair essential cellular processes and/or damage the integrity of their target cells. The following review summarizes major advances in the field of toxin based therapeutics and offers a comprehensive description of the mode of action of each applied toxin.
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Jochmans D, Anders M, Keuleers I, Smeulders L, Kräusslich HG, Kraus G, Müller B. Selective killing of human immunodeficiency virus infected cells by non-nucleoside reverse transcriptase inhibitor-induced activation of HIV protease. Retrovirology 2010; 7:89. [PMID: 20950436 PMCID: PMC2974656 DOI: 10.1186/1742-4690-7-89] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 10/15/2010] [Indexed: 12/03/2022] Open
Abstract
Background Current antiretroviral therapy against human immunodeficiency virus (HIV-1) reduces viral load and thereby prevents viral spread, but it cannot eradicate proviral genomes from infected cells. Cells in immunological sanctuaries as well as cells producing low levels of virus apparently contribute to a reservoir that maintains HIV persistence in the presence of highly active antiretroviral therapy. Thus, accelerated elimination of virus producing cells may represent a complementary strategy to control HIV infection. Here we sought to exploit HIV protease (PR) related cytotoxicity in order to develop a strategy for drug induced killing of HIV producing cells. PR processes the viral Gag and Gag-Pol polyproteins during virus maturation, but is also implicated in killing of virus producing cells through off-target cleavage of host proteins. It has been observed previously that micromolar concentrations of certain non-nucleoside reverse transcriptase inhibitors (NNRTIs) can stimulate intracellular PR activity, presumably by enhancing Gag-Pol dimerization. Results Using a newly developed cell-based assay we compared the degree of PR activation displayed by various NNRTIs. We identified inhibitors showing higher potency with respect to PR activation than previously described for NNRTIs, with the most potent compounds resulting in ~2-fold increase of the Gag processing signal at 250 nM. The degree of enhancement of intracellular Gag processing correlated with the compound's ability to enhance RT dimerization in a mammalian two-hybrid assay. Compounds were analyzed for their potential to mediate specific killing of chronically infected MT-4 cells. Levels of cytotoxicity on HIV infected cells determined for the different NNRTIs corresponded to the relative degree of drug induced intracellular PR activation, with CC50 values ranging from ~0.3 μM to above the tested concentration range (10 μM). Specific cytotoxicity was reverted by addition of PR inhibitors. Two of the most active compounds, VRX-480773 and GW-678248, were also tested in primary human cells and mediated cytotoxicity on HIV-1 infected peripheral blood mononuclear cells. Conclusion These data present proof of concept for targeted drug induced elimination of HIV producing cells. While NNRTIs themselves may not be sufficiently potent for therapeutic application, the results provide a basis for the development of drugs exploiting this mechanism of action.
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Affiliation(s)
- Dirk Jochmans
- Department of Infectious Diseases, Virology, University of Heidelberg, Germany
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45
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MacPherson JI, Dickerson JE, Pinney JW, Robertson DL. Patterns of HIV-1 protein interaction identify perturbed host-cellular subsystems. PLoS Comput Biol 2010; 6:e1000863. [PMID: 20686668 PMCID: PMC2912648 DOI: 10.1371/journal.pcbi.1000863] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Accepted: 06/21/2010] [Indexed: 01/12/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) exploits a diverse array of host cell functions in order to replicate. This is mediated through a network of virus-host interactions. A variety of recent studies have catalogued this information. In particular the HIV-1, Human Protein Interaction Database (HHPID) has provided a unique depth of protein interaction detail. However, as a map of HIV-1 infection, the HHPID is problematic, as it contains curation error and redundancy; in addition, it is based on a heterogeneous set of experimental methods. Based on identifying shared patterns of HIV-host interaction, we have developed a novel methodology to delimit the core set of host-cellular functions and their associated perturbation from the HHPID. Initially, using biclustering, we identify 279 significant sets of host proteins that undergo the same types of interaction. The functional cohesiveness of these protein sets was validated using a human protein-protein interaction network, gene ontology annotation and sequence similarity. Next, using a distance measure, we group host protein sets and identify 37 distinct higher-level subsystems. We further demonstrate the biological significance of these subsystems by cross-referencing with global siRNA screens that have been used to detect host factors necessary for HIV-1 replication, and investigate the seemingly small intersect between these data sets. Our results highlight significant host-cell subsystems that are perturbed during the course of HIV-1 infection. Moreover, we characterise the patterns of interaction that contribute to these perturbations. Thus, our work disentangles the complex set of HIV-1-host protein interactions in the HHPID, reconciles these with siRNA screens and provides an accessible and interpretable map of infection.
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Affiliation(s)
- Jamie I. MacPherson
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester, United Kingdom
| | - Jonathan E. Dickerson
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester, United Kingdom
| | - John W. Pinney
- Centre for Bioinformatics, Division of Molecular Biosciences, Imperial College London, London, United Kingdom
| | - David L. Robertson
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester, United Kingdom
- * E-mail:
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Cummins NW, Jiang W, McGinty J, Bren GD, Bosch RJ, Landay A, Deeks SG, Martin JN, Douek D, Lederman MM, Brenchley J, Badley AD. Intracellular Casp8p41 content is inversely associated with CD4 T cell count. J Infect Dis 2010; 202:386-91. [PMID: 20565257 DOI: 10.1086/653705] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Casp8p41 is a protein fragment generated by cleavage of procaspase 8 by human immunodeficiency virus (HIV) protease. We measured Casp8p41 content in memory CD4 T cells and analyzed the association of Casp8p41 content with CD4 T cell count, cross-sectionally and longitudinally. Casp8p41 content was inversely correlated with CD4 T cell count, and change in Casp8p41 content was associated with absolute CD4 T cell count with change over time. Casp8p41 change was a better predictor of CD4 T cell count change than activated CD8 T cell percentage or viral load and was comparable to bacterial 16s DNA levels. This suggests that Casp8p41 is a relevant mediator of CD4 T cell death during HIV infection.
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Affiliation(s)
- Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA
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Abstract
OBJECTIVE HIV infection of CD4 T cells can lead to HIV protease-mediated cleavage of procaspase 8 generating a novel, HIV-specific peptide called Casp8p41. Casp8p41 has at least two biologic functions: induction of cell death via mitochondrial depolarization and release of cytochrome C, as well as activation of nuclear factor kappa B (NFkappaB). We have previously shown that Casp8p41-induced NFkappaB activation enhances HIV LTR transcription and consequently increases HIV replication. Herein, we questioned whether Casp8p41-induced NFkappaB activation impacts the cytokine profile of cells expressing Casp8p41. DESIGN Analysis of cells expressing Casp8p41 and HIV-infected T cells. METHODS We assessed whether host genes are transcriptionally activated following Casp8p41 production, using microarray analysis, cytokine quantification, followed by western blot and flow cytometry. RESULTS Microarray analysis identified 259 genes significantly upregulated following expression of Casp8p41. Furthermore, Casp8p41 expression in primary CD4 T cells results in increased production of interleukin (IL)-2, IL-15 and tumor necrosis factor (TNF), as well as IL-1RA; whereas levels of granulocyte macrophage colony-stimulating factor and interferon (IFN)-gamma were reduced in the Casp8p41 expressing cells. Intracellular flow cytometry confirmed the co-association of Casp8p41 with elevated TNF in HIV-infected cells. CONCLUSION These data indicate that the expression of Casp8p41 in HIV-infected CD4 T cells in addition to promoting apoptosis and enhancing HIV replication also promotes a proinflammatory cytokine milieu, which is characteristic of untreated HIV infection.
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HIV-1 protease has a genetic T-cell adjuvant effect which is negatively regulated by proteolytic activity. J Virol 2010; 84:7743-9. [PMID: 20484507 DOI: 10.1128/jvi.00747-10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV protease (PR) mediates the processing of human immunodeficiency virus (HIV) polyproteins and is necessary for the viral production. Recently, HIV PR was shown to possess both cytotoxic and chaperone like activity. We demonstrate here that HIV PR can serve as a genetic adjuvant that enhances the HIV Env and human papillomavirus (HPV) DNA vaccine-induced T-cell response in a dose-dependent manner, only when codelivered with DNA vaccine. Interestingly, the T-cell adjuvant effects of HIV PR were increased by introducing several mutations that inhibited its proteolytic activity, indicating that the adjuvant properties were inversely correlated with its proteolytic activity. Conversely, the introduction of a mutation in the flap region of HIV PR limiting the access to the core domain of HIV PR inhibited the T-cell adjuvant effect, suggesting that the HIV PR chaperone like activity may play a role in mediating T-cell adjuvant properties. A similar adjuvant effect was also observed in adenovirus vaccine, indicating vaccine type independency. These findings suggest that HIV PR can modulate T-cell responses elicited by a gene-based vaccine positively by inherent chaperone like activity and negatively by its proteolytic activity.
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Bren GD, Trushin SA, Whitman J, Shepard B, Badley AD. HIV gp120 induces, NF-kappaB dependent, HIV replication that requires procaspase 8. PLoS One 2009; 4:e4875. [PMID: 19287489 PMCID: PMC2653723 DOI: 10.1371/journal.pone.0004875] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 02/18/2009] [Indexed: 12/24/2022] Open
Abstract
Background HIV envelope glycoprotein gp120 causes cellular activation resulting in anergy, apoptosis, proinflammatory cytokine production, and through an unknown mechanism, enhanced HIV replication. Methodology/Principal Findings We describe that the signals which promote apoptosis are also responsible for the enhanced HIV replication. Specifically, we demonstrate that the caspase 8 cleavage fragment Caspase8p43, activates p50/p65 Nuclear Factor κB (NF-κB), in a manner which is inhibited by dominant negative IκBα. This caspase 8 dependent NF-κB activation occurs following stimulation with gp120, TNF, or CD3/CD28 crosslinking, but these treatments do not activate NF-κB in cells deficient in caspase 8. The Casp8p43 cleavage fragment also transactivates the HIV LTR through NF-κB, and the absence of caspase 8 following HIV infection greatly inhibits HIV replication. Conclusion/Significance Gp120 induced caspase 8 dependent NF-κB activation is a novel pathway of HIV replication which increases understanding of the biology of T-cell death, as well as having implications for understanding treatment and prevention of HIV infection.
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Affiliation(s)
- Gary D. Bren
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Sergey A. Trushin
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- Program in Translational Immunovirology and Biodefense, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Joe Whitman
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Brett Shepard
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Andrew D. Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- Program in Translational Immunovirology and Biodefense, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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50
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Rea-Boutrois A, Villet S, Greenland T, Mehlen P, Chebloune Y, Verdier G, Legras-Lachuer C. Small ruminant lentivirus Tat protein induces apoptosis in caprine cells in vitro by the intrinsic pathway. Virology 2009; 383:93-102. [PMID: 19007964 DOI: 10.1016/j.virol.2008.09.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 08/25/2008] [Accepted: 09/26/2008] [Indexed: 01/24/2023]
Abstract
The small ruminant lentiviruses, caprine arthritis-encephalitis virus (CAEV) and maedi visna virus (MVV) naturally cause inflammatory disease in goats and sheep, provoking chronic lesions in several different organs. We have previously demonstrated that in vitro infection of caprine cells by CAEV induces apoptosis through the intrinsic pathway (Rea-Boutrois, A., Pontini, G., Greenland, T., Mehlen, P., Chebloune, Y., Verdier, G. and Legras-Lachuer, C. 2008). In the present study, we used Tat deleted viruses and SLRV Tat-expression vectors to show that the SRLV Tat proteins are responsible for this apoptosis. We have also studied the activation of caspases-3, -8 and -9 by fluorescent assays in caprine cells expressing SRLV Tat proteins, and the effects of transfected dominant negative variants of these caspases, to show that Tat-associated apoptosis depends on activation of caspases-3 and -9, but not -8. A simultaneous disruption of mitochondrial membrane potential indicates an involvement of the mitochondrial pathway.
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Affiliation(s)
- Angela Rea-Boutrois
- Université de Lyon, INRA, UMR754, Université Lyon 1, Ecole Nationale Vétérinaire de Lyon, Ecole Pratique des Hautes Etudes, IFR 128, 50 avenue Tony Garnier, 69 366 Lyon cedex 07, France
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