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In Vitro Anti-SARS-CoV-2 Activity of Selected Metal Compounds and Potential Molecular Basis for Their Actions Based on Computational Study. Biomolecules 2021; 11:biom11121858. [PMID: 34944502 PMCID: PMC8699537 DOI: 10.3390/biom11121858] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 12/24/2022] Open
Abstract
Metal-based drugs represent a rich source of chemical substances of potential interest for the treatment of COVID-19. To this end, we have developed a small but representative panel of nine metal compounds, including both synthesized and commercially available complexes, suitable for medical application and tested them in vitro against the SARS-CoV-2 virus. The screening revealed that three compounds from the panel, i.e., the organogold(III) compound Aubipyc, the ruthenium(III) complex KP1019, and antimony trichloride (SbCl3), are endowed with notable antiviral properties and an acceptable cytotoxicity profile. These initial findings prompted us to perform a computational study to unveil the likely molecular basis of their antiviral actions. Calculations evidenced that the metalation of nucleophile sites in SARS-CoV-2 proteins or nucleobase strands, induced by Aubipyc, SbCl3, and KP1019, is likely to occur. Remarkably, we found that only the deprotonated forms of Cys and Sec residues can react favorably with these metallodrugs. The mechanistic implications of these findings are discussed.
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2
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Pal VK, Agrawal R, Rakshit S, Shekar P, Murthy DTN, Vyakarnam A, Singh A. Hydrogen sulfide blocks HIV rebound by maintaining mitochondrial bioenergetics and redox homeostasis. eLife 2021; 10:68487. [PMID: 34792020 PMCID: PMC8660018 DOI: 10.7554/elife.68487] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 11/17/2021] [Indexed: 01/12/2023] Open
Abstract
A fundamental challenge in human immunodeficiency virus (HIV) eradication is to understand how the virus establishes latency, maintains stable cellular reservoirs, and promotes rebound upon interruption of antiretroviral therapy (ART). Here, we discovered an unexpected role of the ubiquitous gasotransmitter hydrogen sulfide (H2S) in HIV latency and reactivation. We show that reactivation of HIV is associated with downregulation of the key H2S producing enzyme cystathionine-γ-lyase (CTH) and reduction in endogenous H2S. Genetic silencing of CTH disrupts redox homeostasis, impairs mitochondrial function, and remodels the transcriptome of latent cells to trigger HIV reactivation. Chemical complementation of CTH activity using a slow-releasing H2S donor, GYY4137, suppressed HIV reactivation and diminished virus replication. Mechanistically, GYY4137 blocked HIV reactivation by inducing the Keap1-Nrf2 pathway, inhibiting NF-κB, and recruiting the epigenetic silencer, YY1, to the HIV promoter. In latently infected CD4+ T cells from ART-suppressed human subjects, GYY4137 in combination with ART prevented viral rebound and improved mitochondrial bioenergetics. Moreover, prolonged exposure to GYY4137 exhibited no adverse influence on proviral content or CD4+ T cell subsets, indicating that diminished viral rebound is due to a loss of transcription rather than a selective loss of infected cells. In summary, this work provides mechanistic insight into H2S-mediated suppression of viral rebound and suggests exploration of H2S donors to maintain HIV in a latent form.
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Affiliation(s)
- Virender Kumar Pal
- Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Ragini Agrawal
- Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | | | - Pooja Shekar
- BMCRI, Bangalore Medical College and Research Institute, Bangalore, India
| | | | | | - Amit Singh
- Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
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Premadasa LS, Dailey GP, Ruzicka JA, Taylor EW. Selenium-Dependent Read Through of the Conserved 3'-Terminal UGA Stop Codon of HIV-1 nef. AMERICAN JOURNAL OF BIOPHARMACY AND PHARMACEUTICAL SCIENCES 2021; 1:1. [PMID: 35128545 PMCID: PMC8813066 DOI: 10.25259/ajbps_6_2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The HIV-1 nef gene terminates in a 3'-UGA stop codon, which is highly conserved in the main group of HIV-1 subtypes, along with a downstream potential coding region that could extend the nef protein by 33 amino acids, if readthrough of the stop codon occurs. Antisense tethering interactions (ATIs) between a viral mRNA and a host selenoprotein mRNA are a potential viral strategy for the capture of a host selenocysteine insertion sequence (SECIS) element (Taylor et al, 2016) [1]. This mRNA hijacking mechanism could enable the expression of virally encoded selenoprotein modules, via translation of in-frame UGA stop codons as selenocysteine (SeC). Here we show that readthrough of the 3'-terminal UGA codon of nef occurs during translation of HIV-1 nef expression constructs in transfected cells. This was accomplished via fluorescence microscopy image analysis and flow cytometry of HEK 293 cells, transfected with engineered GFP reporter gene plasmid constructs, in which GFP can only be expressed by translational recoding of the UGA codon. SiRNA knockdown of thioredoxin reductase 1 (TR1) mRNA resulted in a 67% decrease in GFP expression, presumably due to reduced availability of the components involved in selenocysteine incorporation for the stop codon readthrough, thus supporting the proposed ATI. Addition of 20 nM sodium selenite to the media significantly enhanced stop codon readthrough in the pNefATI1 plasmid construct, by >100%, supporting the hypothesis that selenium is involved in the UGA readthrough mechanism.
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Affiliation(s)
- Lakmini S. Premadasa
- Department of Chemistry and Biochemistry, Patricia A. Sullivan Science Building PO Box 26170, Greensboro, NC 27402
| | - Gabrielle P. Dailey
- Department of Chemistry and Biochemistry, Patricia A. Sullivan Science Building PO Box 26170, Greensboro, NC 27402
| | - Jan A. Ruzicka
- Department of Basic Pharmaceutical Sciences, Fred C. Wilson School of Pharmacy, High Point University, One University Parkway High Point, NC 27268
| | - Ethan W. Taylor
- Department of Chemistry and Biochemistry, Patricia A. Sullivan Science Building PO Box 26170, Greensboro, NC 27402
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Singh S, Ghosh S, Pal VK, Munshi M, Shekar P, Narasimha Murthy DT, Mugesh G, Singh A. Antioxidant nanozyme counteracts HIV-1 by modulating intracellular redox potential. EMBO Mol Med 2021; 13:e13314. [PMID: 33793064 PMCID: PMC8103102 DOI: 10.15252/emmm.202013314] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 02/05/2021] [Accepted: 02/19/2021] [Indexed: 12/23/2022] Open
Abstract
Reactive oxygen species (ROS) regulates the replication of human immunodeficiency virus (HIV‐1) during infection. However, the application of this knowledge to develop therapeutic strategies remained unsuccessful due to the harmful consequences of manipulating cellular antioxidant systems. Here, we show that vanadium pentoxide (V2O5) nanosheets functionally mimic natural glutathione peroxidase activity to mitigate ROS associated with HIV‐1 infection without adversely affecting cellular physiology. Using genetic reporters of glutathione redox potential and hydrogen peroxide, we showed that V2O5 nanosheets catalyze ROS neutralization in HIV‐1‐infected cells and uniformly block viral reactivation and replication. Mechanistically, V2O5 nanosheets suppressed HIV‐1 by affecting the expression of pathways coordinating redox balance, virus transactivation (e.g., NF‐κB), inflammation, and apoptosis. Importantly, a combination of V2O5 nanosheets with a pharmacological inhibitor of NF‐κB (BAY11‐7082) abrogated reactivation of HIV‐1. Lastly, V2O5 nanosheets inhibit viral reactivation upon prostratin stimulation of latently infected CD4+ T cells from HIV‐infected patients receiving suppressive antiretroviral therapy. Our data successfully revealed the usefulness of V2O5 nanosheets against HIV and suggested nanozymes as future platforms to develop interventions against infectious diseases.
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Affiliation(s)
- Shalini Singh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.,Centre for Infectious Disease Research (CIDR), Indian Institute of Science, Bangalore, India
| | - Sourav Ghosh
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India
| | - Virender Kumar Pal
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.,Centre for Infectious Disease Research (CIDR), Indian Institute of Science, Bangalore, India
| | - MohamedHusen Munshi
- Centre for Infectious Disease Research (CIDR), Indian Institute of Science, Bangalore, India
| | - Pooja Shekar
- Bangalore Medical College and Research Institute, Bangalore, India
| | | | - Govindasamy Mugesh
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India
| | - Amit Singh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.,Centre for Infectious Disease Research (CIDR), Indian Institute of Science, Bangalore, India
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5
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Zhang J, Saad R, Taylor EW, Rayman MP. Selenium and selenoproteins in viral infection with potential relevance to COVID-19. Redox Biol 2020; 37:101715. [PMID: 32992282 PMCID: PMC7481318 DOI: 10.1016/j.redox.2020.101715] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/03/2020] [Accepted: 09/05/2020] [Indexed: 02/07/2023] Open
Abstract
Selenium is a trace element essential to human health largely because of its incorporation into selenoproteins that have a wide range of protective functions. Selenium has an ongoing history of reducing the incidence and severity of various viral infections; for example, a German study found selenium status to be significantly higher in serum samples from surviving than non-surviving COVID-19 patients. Furthermore, a significant, positive, linear association was found between the cure rate of Chinese patients with COVID-19 and regional selenium status. Moreover, the cure rate continued to rise beyond the selenium intake required to optimise selenoproteins, suggesting that selenoproteins are probably not the whole story. Nonetheless, the significantly reduced expression of a number of selenoproteins, including those involved in controlling ER stress, along with increased expression of IL-6 in SARS-CoV-2 infected cells in culture suggests a potential link between reduced selenoprotein expression and COVID-19-associated inflammation. In this comprehensive review, we describe the history of selenium in viral infections and then go on to assess the potential benefits of adequate and even supra-nutritional selenium status. We discuss the indispensable function of the selenoproteins in coordinating a successful immune response and follow by reviewing cytokine excess, a key mediator of morbidity and mortality in COVID-19, and its relationship to selenium status. We comment on the fact that the synthetic redox-active selenium compound, ebselen, has been found experimentally to be a strong inhibitor of the main SARS-CoV-2 protease that enables viral maturation within the host. That finding suggests that redox-active selenium species formed at high selenium intake might hypothetically inhibit SARS-CoV-2 proteases. We consider the tactics that SARS-CoV-2 could employ to evade an adequate host response by interfering with the human selenoprotein system. Recognition of the myriad mechanisms by which selenium might potentially benefit COVID-19 patients provides a rationale for randomised, controlled trials of selenium supplementation in SARS-CoV-2 infection.
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Affiliation(s)
- Jinsong Zhang
- Key Laboratory of Tea Plant Biology and Utilization, School of Tea & Food Science, Anhui Agricultural University, 130 West Changjiang Road, Hefei, 230036, Anhui, PR China
| | - Ramy Saad
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK; Royal Sussex County Hospital, Brighton, BN2 5BE, UK
| | - Ethan Will Taylor
- Department of Chemistry and Biochemistry, University of North Carolina Greensboro, Greensboro, NC 27402, USA
| | - Margaret P Rayman
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
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6
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Guillin OM, Vindry C, Ohlmann T, Chavatte L. Selenium, Selenoproteins and Viral Infection. Nutrients 2019; 11:nu11092101. [PMID: 31487871 PMCID: PMC6769590 DOI: 10.3390/nu11092101] [Citation(s) in RCA: 255] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/23/2019] [Accepted: 08/27/2019] [Indexed: 02/07/2023] Open
Abstract
Reactive oxygen species (ROS) are frequently produced during viral infections. Generation of these ROS can be both beneficial and detrimental for many cellular functions. When overwhelming the antioxidant defense system, the excess of ROS induces oxidative stress. Viral infections lead to diseases characterized by a broad spectrum of clinical symptoms, with oxidative stress being one of their hallmarks. In many cases, ROS can, in turn, enhance viral replication leading to an amplification loop. Another important parameter for viral replication and pathogenicity is the nutritional status of the host. Viral infection simultaneously increases the demand for micronutrients and causes their loss, which leads to a deficiency that can be compensated by micronutrient supplementation. Among the nutrients implicated in viral infection, selenium (Se) has an important role in antioxidant defense, redox signaling and redox homeostasis. Most of biological activities of selenium is performed through its incorporation as a rare amino acid selenocysteine in the essential family of selenoproteins. Selenium deficiency, which is the main regulator of selenoprotein expression, has been associated with the pathogenicity of several viruses. In addition, several selenoprotein members, including glutathione peroxidases (GPX), thioredoxin reductases (TXNRD) seemed important in different models of viral replication. Finally, the formal identification of viral selenoproteins in the genome of molluscum contagiosum and fowlpox viruses demonstrated the importance of selenoproteins in viral cycle.
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Affiliation(s)
- Olivia M Guillin
- CIRI, Centre International de Recherche en Infectiologie, CIRI, 69007 Lyon, France
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité U1111, 69007 Lyon, France
- Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Université Claude Bernard Lyon 1 (UCBL1), 69622 Lyon, France
- Unité Mixte de Recherche 5308 (UMR5308), Centre national de la recherche scientifique (CNRS), 69007 Lyon, France
| | - Caroline Vindry
- CIRI, Centre International de Recherche en Infectiologie, CIRI, 69007 Lyon, France
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité U1111, 69007 Lyon, France
- Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Université Claude Bernard Lyon 1 (UCBL1), 69622 Lyon, France
- Unité Mixte de Recherche 5308 (UMR5308), Centre national de la recherche scientifique (CNRS), 69007 Lyon, France
| | - Théophile Ohlmann
- CIRI, Centre International de Recherche en Infectiologie, CIRI, 69007 Lyon, France
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité U1111, 69007 Lyon, France
- Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Université Claude Bernard Lyon 1 (UCBL1), 69622 Lyon, France
- Unité Mixte de Recherche 5308 (UMR5308), Centre national de la recherche scientifique (CNRS), 69007 Lyon, France
| | - Laurent Chavatte
- CIRI, Centre International de Recherche en Infectiologie, CIRI, 69007 Lyon, France.
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité U1111, 69007 Lyon, France.
- Ecole Normale Supérieure de Lyon, 69007 Lyon, France.
- Université Claude Bernard Lyon 1 (UCBL1), 69622 Lyon, France.
- Unité Mixte de Recherche 5308 (UMR5308), Centre national de la recherche scientifique (CNRS), 69007 Lyon, France.
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7
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Taylor EW, Ruzicka JA, Premadasa L, Zhao L. Cellular Selenoprotein mRNA Tethering via Antisense Interactions with Ebola and HIV-1 mRNAs May Impact Host Selenium Biochemistry. Curr Top Med Chem 2016; 16:1530-5. [PMID: 26369818 PMCID: PMC4997913 DOI: 10.2174/1568026615666150915121633] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 08/23/2015] [Accepted: 08/25/2015] [Indexed: 02/06/2023]
Abstract
Regulation of protein expression by non-coding RNAs typically involves effects on mRNA degradation and/or ribosomal translation. The possibility of virus-host mRNA-mRNA antisense tethering interactions (ATI) as a gain-of-function strategy, via the capture of functional RNA motifs, has not been hitherto considered. We present evidence that ATIs may be exploited by certain RNA viruses in order to tether the mRNAs of host selenoproteins, potentially exploiting the proximity of a captured host selenocysteine insertion sequence (SECIS) element to enable the expression of virally-encoded selenoprotein modules, via translation of in-frame UGA stop codons as selenocysteine. Computational analysis predicts thermodynamically stable ATIs between several widely expressed mammalian selenoprotein mRNAs (e.g., isoforms of thioredoxin reductase) and specific Ebola virus mRNAs, and HIV-1 mRNA, which we demonstrate via DNA gel shift assays. The probable functional significance of these ATIs is further supported by the observation that, in both viruses, they are located in close proximity to highly conserved in-frame UGA stop codons at the 3′ end of open reading frames that encode essential viral proteins (the HIV-1 nef protein and the Ebola nucleoprotein). Significantly, in HIV/AIDS patients, an inverse correlation between serum selenium and mortality has been repeatedly documented, and clinical benefits of selenium in the context of multi-micronutrient supplementation have been demonstrated in several well-controlled clinical trials. Hence, in the light of our findings, the possibility of a similar role for selenium in Ebola pathogenesis and treatment merits serious investigation.
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Affiliation(s)
- Ethan Will Taylor
- Dept. of Nanoscience, University of North Carolina at Greensboro, Joint School of Nanoscience and Nanoengineering, 2907 E. Gate City Blvd., Greensboro, NC 27401 USA.
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8
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Bhaskar A, Munshi M, Khan SZ, Fatima S, Arya R, Jameel S, Singh A. Measuring glutathione redox potential of HIV-1-infected macrophages. J Biol Chem 2014; 290:1020-38. [PMID: 25406321 PMCID: PMC4294471 DOI: 10.1074/jbc.m114.588913] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Redox signaling plays a crucial role in the pathogenesis of human immunodeficiency virus type-1 (HIV-1). The majority of HIV redox research relies on measuring redox stress using invasive technologies, which are unreliable and do not provide information about the contributions of subcellular compartments. A major technological leap emerges from the development of genetically encoded redox-sensitive green fluorescent proteins (roGFPs), which provide sensitive and compartment-specific insights into redox homeostasis. Here, we exploited a roGFP-based specific bioprobe of glutathione redox potential (EGSH; Grx1-roGFP2) and measured subcellular changes in EGSH during various phases of HIV-1 infection using U1 monocytic cells (latently infected U937 cells with HIV-1). We show that although U937 and U1 cells demonstrate significantly reduced cytosolic and mitochondrial EGSH (approximately −310 mV), active viral replication induces substantial oxidative stress (EGSH more than −240 mV). Furthermore, exposure to a physiologically relevant oxidant, hydrogen peroxide (H2O2), induces significant deviations in subcellular EGSH between U937 and U1, which distinctly modulates susceptibility to apoptosis. Using Grx1-roGFP2, we demonstrate that a marginal increase of about ∼25 mV in EGSH is sufficient to switch HIV-1 from latency to reactivation, raising the possibility of purging HIV-1 by redox modulators without triggering detrimental changes in cellular physiology. Importantly, we show that bioactive lipids synthesized by clinical drug-resistant isolates of Mycobacterium tuberculosis reactivate HIV-1 through modulation of intracellular EGSH. Finally, the expression analysis of U1 and patient peripheral blood mononuclear cells demonstrated a major recalibration of cellular redox homeostatic pathways during persistence and active replication of HIV.
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Affiliation(s)
- Ashima Bhaskar
- From the Department of Microbiology and Cell Biology, Centre for Infectious Disease and Research, Indian Institute of Sciences, Bangalore 560012
| | - MohamedHusen Munshi
- From the Department of Microbiology and Cell Biology, Centre for Infectious Disease and Research, Indian Institute of Sciences, Bangalore 560012, the Department of Biotechnology, Jamia Millia Islamia, New Delhi 25, India
| | - Sohrab Zafar Khan
- the International Centre for Genetic Engineering and Biotechnology, New Delhi 110 67, and
| | - Sadaf Fatima
- the Department of Biotechnology, Jamia Millia Islamia, New Delhi 25, India
| | - Rahul Arya
- the International Centre for Genetic Engineering and Biotechnology, New Delhi 110 67, and
| | - Shahid Jameel
- the International Centre for Genetic Engineering and Biotechnology, New Delhi 110 67, and
| | - Amit Singh
- From the Department of Microbiology and Cell Biology, Centre for Infectious Disease and Research, Indian Institute of Sciences, Bangalore 560012,
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Cummins NW, Badley AD. Anti-apoptotic mechanisms of HIV: lessons and novel approaches to curing HIV. Cell Mol Life Sci 2013; 70:3355-63. [PMID: 23275944 PMCID: PMC3753464 DOI: 10.1007/s00018-012-1239-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 11/18/2012] [Accepted: 12/10/2012] [Indexed: 12/17/2022]
Abstract
Past efforts at curing infection with the human immunodeficiency virus (HIV) have been blocked by the resistance of some infected cells to viral cytopathic effects and the associated development of a latent viral reservoir. Furthermore, current efforts to clear the viral reservoir by means of reactivating latent virus are hampered by the lack of cell death in the newly productively infected cells. The purpose of this review is to describe the many anti-apoptotic mechanisms of HIV, as well as the current limitations in the field. Only by understanding how infected cells avoid HIV-induced cell death can an effective strategy to kill infected cells be developed.
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Affiliation(s)
- Nathan W Cummins
- Division of Infectious Diseases, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA.
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10
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Masanetz S, Lehmann MH. HIV-1 Nef increases astrocyte sensitivity towards exogenous hydrogen peroxide. Virol J 2011; 8:35. [PMID: 21255447 PMCID: PMC3038946 DOI: 10.1186/1743-422x-8-35] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 01/22/2011] [Indexed: 01/20/2023] Open
Abstract
Background HIV-1 infected individuals are under chronic exposure to reactive oxygen species (ROS) considered to be instrumental in the progression of AIDS and the development of HIV-1 associated dementia (HAD). Astrocytes support neuronal function and protect them against cytotoxic substances including ROS. The protein HIV-1 Nef, a progression factor in AIDS pathology is abundantly expressed in astrocytes in patients with HAD, and thus may influence its functions. Results Endogenous expressed HIV-1 Nef leads to increased sensitivity of human astrocytes towards exogenous hydrogen peroxide but not towards TNF-alpha. Cell death of nef-expressing astrocytes exposed to 10 μM hydrogen peroxide for 30 min occurred within 4 h. Conclusion HIV-1 Nef may contribute to neuronal dysfunction and the development of HAD by causing death of astrocytes through decreasing their tolerance for hydrogen peroxide.
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Affiliation(s)
- Sabine Masanetz
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, 81675 Munich, Germany
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Bouzar AB, Boxus M, Florins A, François C, Reichert M, Willems L. Reduced levels of reactive oxygen species correlate with inhibition of apoptosis, rise in thioredoxin expression and increased bovine leukemia virus proviral loads. Retrovirology 2009; 6:102. [PMID: 19903329 PMCID: PMC2779800 DOI: 10.1186/1742-4690-6-102] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 11/10/2009] [Indexed: 12/11/2022] Open
Abstract
Background Bovine Leukemia virus (BLV) is a deltaretrovirus that induces lymphoproliferation and leukemia in ruminants. In ex vivo cultures of B lymphocytes isolated from BLV-infected sheep show that spontaneous apoptosis is reduced. Here, we investigated the involvement of reactive oxygen species (ROS) in this process. Results We demonstrate that (i) the levels of ROS and a major product of oxidative stress (8-OHdG) are reduced, while the thioredoxin antioxidant protein is highly expressed in BLV-infected B lymphocytes, (ii) induction of ROS by valproate (VPA) is pro-apoptotic, (iii) inversely, the scavenging of ROS with N-acetylcysteine inhibits apoptosis, and finally (iv) the levels of ROS inversely correlate with the proviral loads. Conclusion Together, these observations underline the importance of ROS in the mechanisms of inhibition of apoptosis linked to BLV infection.
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Affiliation(s)
- Amel Baya Bouzar
- Université de Liège (ULg), Gembloux Agro-Bio Tech, Molecular and Cellular Biology, Gembloux, Belgium.
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12
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Aquaro S, Scopelliti F, Pollicita M, Perno CF. Oxidative stress and HIV infection: target pathways for novel therapies? ACTA ACUST UNITED AC 2008. [DOI: 10.2217/17469600.2.4.327] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Oxidative stress is thought to play an important role in the progression of HIV infection. fact, it has been observed that perturbations in antioxidant defense systems, and consequently redox imbalance, are present in many tissues of HIV-infected patients. Moreover, there is clear evidence that oxidative stress may contribute to several aspects of HIV disease, including viral replication, inflammatory response and decreased immune cell proliferation. For this reason, the exogenous supply of antioxidants, as natural compounds and new-generation antioxidants that scavenge free radicals, might represent an important additional strategy for the treatment of HIV infection in the era after HAART therapy has been applied.
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Affiliation(s)
- Stefano Aquaro
- Campus di Arcavacata, Edificio Polifunzionale, Via Pietro Bucci, 87036 Arcavacata di Rende (CS), Italy and University of Calabria, Department of Pharmaco-Biology, Rende(CS), Italy
| | - Fernanda Scopelliti
- Department of Experimental Medicine & Biochemical Sciences, University of Tor Vergata Via Montpellier 1 00133, Rome, Italy
| | - Michela Pollicita
- Department of Experimental Medicine & Biochemical Sciences, University of Tor Vergata Via Montpellier 1 00133, Rome, Italy
| | - Carlo Federico Perno
- Department of Experimental Medicine & Biochemical Sciences, University of Tor Vergata Via Montpellier 1 00133, Rome, Italy
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Moghadaszadeh B, Beggs AH. Selenoproteins and their impact on human health through diverse physiological pathways. Physiology (Bethesda) 2006; 21:307-15. [PMID: 16990451 PMCID: PMC3372916 DOI: 10.1152/physiol.00021.2006] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In the last few decades, the importance of selenium in human health has been the subject of numerous studies. It is believed that the physiological effects of selenium occur mainly through the function of selenoproteins, which incorporate selenium in the form of one or more selenocysteine residues. Recent advances in understanding the complex regulation of selenoprotein synthesis and functional characterization of several members of the selenoprotein family have contributed to an improved comprehension of the role(s) of selenium in human health and the great diversity of physiological pathways influenced by this trace element.
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14
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Jacob BA, Porter KM, Elms SC, Cheng PY, Jones DP, Sutliff RL. HIV-1-induced pulmonary oxidative and nitrosative stress: exacerbated response to endotoxin administration in HIV-1 transgenic mouse model. Am J Physiol Lung Cell Mol Physiol 2006; 291:L811-9. [PMID: 16728526 DOI: 10.1152/ajplung.00468.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Human immunodeficiency virus (HIV)-1 causes lung disease by increasing the host's susceptibility to pathogens. HIV-1 also causes an increase in systemic oxidative/nitrosative stress, perhaps enhancing the deleterious effects of secondary infections. Here we examined the ability of HIV-1 proteins to increase lung oxidative/nitrosative stress after lipopolysaccharide (LPS) (endotoxin) administration in an HIV-1 transgenic mouse model. Lung oxidative/nitrosative stress biomarkers studied 3 and 6 h after LPS administration were as follows: lung edema, tissue superoxide, NO metabolites, nitrotyrosine, hydrogen peroxide, and bronchoalveolar lavage fluid (BALF) glutathione (GSH). Blood serum cytokine levels were quantified to verify immune function of our nonimmunocompromised animal model. Results indicate that 3 h after LPS administration, HIV-1 transgenic mouse lung tissue has significantly greater edema and superoxide. Furthermore, NO metabolites are significantly elevated in HIV-1 transgenic mouse BALF, lung tissue, and blood plasma compared with those of wild-type mice. HIV-1 transgenic mice also produce significantly greater lung nitrotyrosine and hydrogen peroxide than wild-type mice. In addition, HIV-1 transgenic mice produce significantly less BALF GSH than wild-type mice 3 h after LPS treatment. Without treatment, serum cytokine levels are similar for HIV-1 transgenic and wild-type mice. After treatment, serum cytokine levels are significantly elevated in both HIV-1 transgenic and wild-type mice. Therefore, HIV-1 transgenic mice have significantly greater lung oxidative/nitrosative stress after endotoxin administration than wild-type mice, independent of immune function. These results indicate that HIV-1 proteins may increase pulmonary complications subsequent to a secondary infection by altering the lung redox potential.
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Affiliation(s)
- Barbara A Jacob
- Department of Pulmonary and Critical Care Medicine, Center for Clinical and Molecular Nutrition, Emory University School of Medicine, Veterans Affairs Medical Center, 1670 Clairmont Rd., Atlanta, GA 30033, USA
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Perfettini JL, Castedo M, Roumier T, Andreau K, Nardacci R, Piacentini M, Kroemer G. Mechanisms of apoptosis induction by the HIV-1 envelope. Cell Death Differ 2006; 12 Suppl 1:916-23. [PMID: 15719026 DOI: 10.1038/sj.cdd.4401584] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The envelope glycoprotein complex (Env) of human immunodeficiency virus-1 (HIV-1) can induce apoptosis by a cornucopia of distinct mechanisms. A soluble Env derivative, gp120, can kill cells through signals that are transmitted by chemokine receptors such as CXCR4. Cell surface-bound Env (gp120/gp41), as present on the plasma membrane of HIV-1-infected cells, can kill uninfected bystander cells expressing CD4 and CXCR4 (or similar chemokine receptors, depending on the Env variant) by at least three different mechanisms. First, a transient interaction involving the exchange of lipids between the two interacting cells ('the kiss of death') may lead to the selective death of single CD4-expressing target cells. Second, fusion of the interacting cells may lead to the formation of syncytia which then succumb to apoptosis in a complex pathway involving the activation of several kinases (cyclin-dependent kinase-1, Cdk1; checkpoint kinase-2, Chk2; mammalian target of rapamycin, mTOR; p38 mitogen-activated protein kinase, p38 MAPK; inhibitor of NF-kappaB kinase, IKK), as well as the activation of several transcription factors (NF-kappaB, p53), finally resulting in the activation of the mitochondrial pathway of apoptosis. Third, if the Env-expressing cell is at an early stage of imminent apoptosis, its fusion with a CD4-expressing target cell can precipitate the death of both cells, through a process that may be considered as contagious apoptosis and which does not involve Cdk1, mTOR, p38 nor p53, yet does involve mitochondria. Activation of some of the above- mentioned lethal signal transducers have been detected in patients' tissues, suggesting that HIV-1 may indeed trigger apoptosis through molecules whose implication in Env-induced killing has initially been discovered in vitro.
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Affiliation(s)
- J-L Perfettini
- CNRS-UMR8125, Institut Gustave Roussy, 39 rue Camille-Desmoulins, Villejuif, France
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Abstract
In an alternate reading frame overlapping the viral envelope gene, HIV-1 has been shown to encoded a truncated glutathione peroxidase (GPx) module. Essential active site residues of the catalytic core regions of mammalian GPx sequences are conserved in the putative viral GPx (vGPx, encoded by the env-fs gene). Cells transfected with an HIV-1 env-fs construct show up to a 100% increase in GPx enzyme activity, and are protected against the loss of mitochondrial transmembrane potential and subsequent cell death induced by exogenous oxidants or mitochondrial reactive oxygen species. An intact vGPx gene was observed to be more common in HIV-1-infected long-term non-progressors, as compared to HIV-1 isolates from patients developing AIDS. An antioxidant/antiapoptotic protective role of the vGPx is also consistent with the observation that -1 frameshifting induced by the HIV-1 env-fs sequence AAAAAGA (which contains a potential "hungry" arginine codon, AGA) increases during arginine deficiency, which has been associated with increased oxidative stress. Under arginine-limited conditions, nitric oxide synthase generates superoxide, which rapidly combines with NO to form peroxynitrite, which can cause activated T-cells to undergo apoptosis. Thus, biosynthesis of the HIV-1 GPx as an adaptive response to low arginine conditions might delay oxidant-induced apoptotic cell death, providing an enhanced opportunity for viral replication.
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Affiliation(s)
- Lijun Zhao
- Office of Research and Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, PO Box 26170, Greensboro, NC 27402-6170, USA
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Olubajo B, Taylor EW. A -1 frameshift in the HIV-1 env gene is enhanced by arginine deficiency via a hungry codon mechanism. Mutat Res 2005; 579:125-32. [PMID: 16055159 DOI: 10.1016/j.mrfmmm.2005.02.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2004] [Revised: 02/16/2005] [Accepted: 02/16/2005] [Indexed: 11/21/2022]
Abstract
Ribosomal frameshifting is used by various organisms to maximize protein coding potential of genomic sequences. It is commonly exploited by RNA viruses to overcome the constraint of their limited genome size. Frameshifting requires specific RNA structural features, such as a suitable heptanucleotide "slippery" sequence and an RNA pseudoknot. Previous genomic analysis of HIV-1 indicated the potential for several hidden genes encoded through frameshifting; one of these, overlapping the envelope gene, has an RNA pseudoknot just downstream from a slippery sequence, AAAAAGA that features an adenine quadruplet prior to a potential hungry arginine codon (AGA). This env-frameshift (env-fs) gene has been shown to encode a truncated glutathione peroxidase homologue, with both antioxidant and anti-apoptotic activities in transfected cells. Using a dual reporter cell-based frameshift assay, we demonstrate that the env-fs frameshift sequence is active in vitro. Furthermore, in arginine deficient media, env-fs frameshifting increased over 100% (p<0.005), consistent with the hypothesized hungry codon mechanism. As a response to arginine deficiency, increased expression of the antioxidant viral GPx gene (env-fs) by upregulation of frameshifting could be protective to HIV-infected cells, as a countermeasure to the increased oxidative stress induced by arginine deficiency (because NO is a known scavenger of hydroxyl radical).
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Affiliation(s)
- Babatunde Olubajo
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602-2352, USA
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Su G, Min W, Taylor EW. An HIV-1 encoded peptide mimics the DNA binding loop of NF-kappaB and binds thioredoxin with high affinity. Mutat Res 2005; 579:133-48. [PMID: 16054658 DOI: 10.1016/j.mrfmmm.2005.02.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Revised: 02/16/2005] [Accepted: 02/16/2005] [Indexed: 10/25/2022]
Abstract
Pro-fs is a human immunodeficiency virus type 1 (HIV-l)-encoded putative selenoprotein, predicted by a theoretical analysis of the viral genome; it is potentially expressed by a -1 frameshift from the protease coding region. Pro-fs has significant sequence similarity to the DNA binding loop of nuclear factor kappa B (NF-kappaB), which is known to bind thioredoxin (Trx). We hypothesize that the putative HIV-1 pro-fs gene product functions by mimicry of NF-kappaB via binding to Trx. The hypothesis was tested in vitro by co-immunoprecipitation and GST-pull down assays, using a purified mutant pro-fs protein, in which the two potential selenocysteine residues were mutated to cysteines, in order to permit expression in bacteria. Both experiments showed that pro-fs binds to human wild type Trx (Trx-wt) with high affinity. Mutation of the two conserved cysteine residues in the Trx active site redox center to serine (Ser) (Trx-CS) weakened but failed to abolish the interaction. In pro-fs-transfected 293T cells, using confocal microscopy and fluorescence resonance energy transfer (FRET), we have observed that pro-fs localizes in cell nuclei and forms oligomers. Upon stimulation by phorbol 12-myristate 13-acetate (PMA), Trx translocates into cell nuclei. Significant FRET efficiency was detected in the nuclei of PMA-stimulated 293T cells co-expressing fluorescence-tagged pro-fs and Trx-wt or Trx-CS. These results indicate that in living cells the double cysteine mutant of pro-fs binds to both Trx and Trx-CS with high affinity, suggesting that Trx-pro-fs binding is a structurally-specific interaction, involving more of the Trx molecule than just its active site cysteine residues. These results establish the capacity for functional mimicry of the Trx binding ability of the NF-kappaB/Rel family of transcription factors by the putative HIV-1 pro-fs protein.
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Affiliation(s)
- Guoping Su
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602-2352, USA.
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