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HIV-1 Nef Protein Affects Cytokine and Extracellular Vesicles Production in the GEN2.2 Plasmacytoid Dendritic Cell Line. Viruses 2021; 14:v14010074. [PMID: 35062278 PMCID: PMC8780779 DOI: 10.3390/v14010074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/24/2021] [Accepted: 12/28/2021] [Indexed: 11/16/2022] Open
Abstract
Plasmacytoid dendritic cells (pDCs) are a unique dendritic cell subset specialized in type I interferon production, whose role in Human Immunodeficiency Virus (HIV) infection and pathogenesis is complex and not yet well defined. Considering the crucial role of the accessory protein Nef in HIV pathogenicity, possible alterations in intracellular signalling and extracellular vesicle (EV) release induced by exogenous Nef on uninfected pDCs have been investigated. As an experimental model system, a human plasmacytoid dendritic cell line, GEN2.2, stimulated with a myristoylated recombinant NefSF2 protein was employed. In GEN2.2 cells, Nef treatment induced the tyrosine phosphorylation of STAT-1 and STAT-2 and the production of a set of cytokines, chemokines and growth factors including IP-10, MIP-1β, MCP-1, IL-8, TNF-α and G-CSF. The released factors differed both in type and amount from those released by macrophages treated with the same viral protein. Moreover, Nef treatment slightly reduces the production of small EVs, and the protein was found associated with the small (size < 200 nm) but not the medium/large vesicles (size > 200 nm) collected from GEN2.2 cells. These results add new information on the interactions between this virulence factor and uninfected pDCs, and may provide the basis for further studies on the interactions of Nef protein with primary pDCs.
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The Role of Extracellular Vesicles as Allies of HIV, HCV and SARS Viruses. Viruses 2020; 12:v12050571. [PMID: 32456011 PMCID: PMC7291340 DOI: 10.3390/v12050571] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/15/2020] [Accepted: 05/20/2020] [Indexed: 12/16/2022] Open
Abstract
Extracellular vesicles (EVs) are lipid bilayer-enclosed entities containing proteins and nucleic acids that mediate intercellular communication, in both physiological and pathological conditions. EVs resemble enveloped viruses in both structural and functional aspects. In full analogy with viral biogenesis, some of these vesicles are generated inside cells and, once released into the extracellular milieu, are called “exosomes”. Others bud from the plasma membrane and are generally referred to as “microvesicles”. In this review, we will discuss the state of the art of the current studies on the relationship between EVs and viruses and their involvement in three important viral infections caused by HIV, HCV and Severe Acute Respiratory Syndrome (SARS) viruses. HIV and HCV are two well-known pathogens that hijack EVs content and release to create a suitable environment for viral infection. SARS viruses are a new entry in the world of EVs studies, but are equally important in this historical framework. A thorough knowledge of the involvement of the EVs in viral infections could be helpful for the development of new therapeutic strategies to counteract different pathogens.
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Kamalzare S, Noormohammadi Z, Rahimi P, Atyabi F, Irani S, Tekie FSM, Mottaghitalab F. Carboxymethyl dextran‐trimethyl chitosan coated superparamagnetic iron oxide nanoparticles: An effective siRNA delivery system for HIV‐1 Nef. J Cell Physiol 2019; 234:20554-20565. [DOI: 10.1002/jcp.28655] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/16/2019] [Accepted: 03/19/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Sara Kamalzare
- Department of Biology, School of Basic Sciences Science and Research Branch, Islamic Azad University (IAU) Tehran Iran
| | - Zahra Noormohammadi
- Department of Biology, School of Basic Sciences Science and Research Branch, Islamic Azad University (IAU) Tehran Iran
| | - Pooneh Rahimi
- Department of Hepatitis and AIDS Pasteur Institute of Iran Tehran Iran
| | - Fatemeh Atyabi
- Department of Pharmaceutics Tehran University of Medical Sciences Tehran Iran
- Nanotechnology Research Centre Faculty of Pharmacy, Tehran University of Medical Sciences Tehran Iran
| | - Shiva Irani
- Department of Biology, School of Basic Sciences Science and Research Branch, Islamic Azad University (IAU) Tehran Iran
| | | | - Fatemeh Mottaghitalab
- Nanotechnology Research Centre Faculty of Pharmacy, Tehran University of Medical Sciences Tehran Iran
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New targets for HIV drug discovery. Drug Discov Today 2019; 24:1139-1147. [PMID: 30885676 DOI: 10.1016/j.drudis.2019.03.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/23/2019] [Accepted: 03/11/2019] [Indexed: 02/07/2023]
Abstract
Recent estimates suggest close to one million people per year die globally owing to HIV-related illnesses. Therefore, there is still a need to identify new targets to develop future treatments. Many of the more recently identified targets are host-related and these might be more difficult for the virus to develop drug resistance to. In addition, there are virus-related targets (capsid and RNAse H) that have yet to be exploited clinically. Several of the newer targets also address virulence factors, virus latency or target persistence. The targets highlighted in this review could represent the next generation of viable candidates for drug discovery projects as well as continue the search for a cure for this disease.
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Uhl J, Gujarathi S, Waheed AA, Gordon A, Freed EO, Gousset K. Myosin-X is essential to the intercellular spread of HIV-1 Nef through tunneling nanotubes. J Cell Commun Signal 2018; 13:209-224. [PMID: 30443895 DOI: 10.1007/s12079-018-0493-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 11/01/2018] [Indexed: 12/18/2022] Open
Abstract
Tunneling nanotubes (TNTs) are intercellular structures that allow for the passage of vesicles, organelles, genomic material, pathogenic proteins and pathogens. The unconventional actin molecular motor protein Myosin-X (Myo10) is a known inducer of TNTs in neuronal cells, yet its role in other cell types has not been examined. The Nef HIV-1 accessory protein is critical for HIV-1 pathogenesis and can self-disseminate in culture via TNTs. Understanding its intercellular spreading mechanism could reveal ways to control its damaging effects during HIV-1 infection. Our goal in this study was to characterize the intercellular transport mechanism of Nef from macrophages to T cells. We demonstrate that Nef increases TNTs in a Myo10-dependent manner in macrophages and observed the transfer of Nef via TNTs from macrophages to T cells. To quantify this transfer mechanism, we established an indirect flow cytometry assay. Since Nef expression in T cells down-regulates the surface receptor CD4, we correlated the decrease in CD4 to the transfer of Nef between these cells. Thus, we co-cultured macrophages expressing varying levels of Nef with a T cell line expressing high levels of CD4 and quantified the changes in CD4 surface expression resulting from Nef transfer. We demonstrate that Nef transfer occurs via a cell-to-cell dependent mechanism that directly correlates with the presence of Myo10-dependent TNTs. Thus, we show that Nef can regulate Myo10 expression, thereby inducing TNT formation, resulting in its own transfer from macrophages to T cells. In addition, we demonstrate that up-regulation of Myo10 induced by Nef also occurs in human monocyte derived macrophages during HIV-1 infection.
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Affiliation(s)
- Jaime Uhl
- Biology Department, California State University Fresno, Fresno, 93740, USA
| | - Shivalee Gujarathi
- Biology Department, California State University Fresno, Fresno, 93740, USA
| | - Abdul A Waheed
- HIV Dynamics and Replication Program, National Cancer Institute-Frederick, Frederick, MD, 21702, USA
| | - Ana Gordon
- Biology Department, California State University Fresno, Fresno, 93740, USA
| | - Eric O Freed
- HIV Dynamics and Replication Program, National Cancer Institute-Frederick, Frederick, MD, 21702, USA
| | - Karine Gousset
- Biology Department, California State University Fresno, Fresno, 93740, USA.
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Ferrantelli F, Manfredi F, Chiozzini C, Anticoli S, Olivetta E, Arenaccio C, Federico M. DNA Vectors Generating Engineered Exosomes Potential CTL Vaccine Candidates Against AIDS, Hepatitis B, and Tumors. Mol Biotechnol 2018; 60:773-782. [PMID: 30167966 DOI: 10.1007/s12033-018-0114-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Eukaryotic cells constitutively produce nanovesicles of 50-150 nm of diameter, referred to as exosomes, upon release of the contents of multivesicular bodies (MVBs). We recently characterized a novel, exosome-based way to induce cytotoxic T lymphocyte (CTL) immunization against full-length antigens. It is based on DNA vectors expressing products of fusion between the exosome-anchoring protein Nef mutant (Nefmut) with the antigen of interest. The strong efficiency of Nefmut to accumulate in MVBs results in the production of exosomes incorporating huge amounts of the desired antigen. When translated in animals, the injection of Nefmut-based DNA vectors generates engineered exosomes whose internalization in antigen-presenting cells induces cross-priming and antigen-specific CTL immunity. Here, we describe the molecular strategies we followed to produce DNA vectors aimed at generating immunogenic exosomes potentially useful to elicit a CTL immune response against antigens expressed by the etiologic agents of major chronic viral infections, i.e., HIV-1, HBV, and the novel tumor-associated antigen HOXB7. Unique methods intended to counteract intrinsic RNA instability and nuclear localization of the antigens have been developed. The success we met with the production of these engineered exosomes opens the way towards pre-clinic experimentations devoted to the optimization of new vaccine candidates against major infectious and tumor pathologies.
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Affiliation(s)
- Flavia Ferrantelli
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Francesco Manfredi
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Chiara Chiozzini
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Simona Anticoli
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Eleonora Olivetta
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Claudia Arenaccio
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Maurizio Federico
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy.
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Anticoli S, Aricò E, Arenaccio C, Manfredi F, Chiozzini C, Olivetta E, Ferrantelli F, Lattanzi L, D'Urso MT, Proietti E, Federico M. Engineered exosomes emerging from muscle cells break immune tolerance to HER2 in transgenic mice and induce antigen-specific CTLs upon challenge by human dendritic cells. J Mol Med (Berl) 2017; 96:211-221. [PMID: 29282521 DOI: 10.1007/s00109-017-1617-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/12/2017] [Accepted: 12/18/2017] [Indexed: 12/11/2022]
Abstract
We recently described a novel biotechnological platform for the production of unrestricted cytotoxic T lymphocyte (CTL) vaccines. It relies on in vivo engineering of exosomes, i.e., nanovesicles constitutively released by all cells, with full-length antigens of choice upon fusion with an exosome-anchoring protein referred to as Nefmut. They are produced upon intramuscular injection of a DNA vector and, when uploaded with a viral tumor antigen, were found to elicit an immune response inhibiting the tumor growth in a model of transplantable tumors. However, for a possible application in cancer immunotherapy, a number of key issues remained unmet. Among these, we investigated: (i) whether the immunogenic stimulus induced by the engineered exosomes can break immune tolerance, and (ii) their effectiveness when applied in human system. As a model of immune tolerance, we considered mice transgenic for the expression of activated rat HER2/neu which spontaneously develop adenocarcinomas in all mammary glands. When these mice were injected with a DNA vector expressing the product of fusion between Nefmut and the extracellular domain of HER2/neu, antigen-specific CD8+ T lymphocytes became readily detectable. This immune response associated with a HER2-directed CTL activity and a significant delay in tumor development. On the other hand, through cross-priming experiments, we demonstrated the effectiveness of the engineered exosomes emerging from transfected human primary muscle cells in inducing antigen-specific CTLs. We propose our CTL vaccine platform as part of new immunotherapy strategies against tumors expressing self-antigens, i.e., products highly expressed in oncologic lesions but tolerated by the immune system. KEY MESSAGES We established a novel, exosome-based method to produce unrestricted CTL vaccines. This strategy is effective in breaking the tolerance towards tumor self-antigens. Our method is also useful to elicit antigen-specific CTL immunity in humans. These findings open the way towards the use of this antitumor strategy in clinic.
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Affiliation(s)
- Simona Anticoli
- National Center for Global Health, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy
| | - Eleonora Aricò
- FabioCell, Core Facilities, ISS, Viale Regina Elena 299, 00161, Rome, Italy
| | - Claudia Arenaccio
- National Center for Global Health, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy
| | - Francesco Manfredi
- National Center for Global Health, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy
| | - Chiara Chiozzini
- National Center for Global Health, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy
| | - Eleonora Olivetta
- National Center for Global Health, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy
| | - Flavia Ferrantelli
- National Center for Global Health, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy
| | - Laura Lattanzi
- Department of Oncology and Molecular Medicine, ISS, Viale Regina Elena 299, 00161, Rome, Italy
| | - Maria Teresa D'Urso
- National Center for Animal Experimentation and Health, ISS, Viale Regina Elena 299, 00161, Rome, Italy
| | - Enrico Proietti
- Department of Oncology and Molecular Medicine, ISS, Viale Regina Elena 299, 00161, Rome, Italy
| | - Maurizio Federico
- National Center for Global Health, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy.
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Lamers SL, Fogel GB, Liu ES, Barbier AE, Rodriguez CW, Singer EJ, Nolan DJ, Rose R, McGrath MS. Brain-specific HIV Nef identified in multiple patients with neurological disease. J Neurovirol 2017; 24:1-15. [PMID: 29063512 DOI: 10.1007/s13365-017-0586-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 08/28/2017] [Accepted: 10/03/2017] [Indexed: 12/11/2022]
Abstract
HIV-1 Nef is a flexible, multifunctional protein with several cellular targets that is required for pathogenicity of the virus. This protein maintains a high degree of genetic variation among intra- and inter-host isolates. HIV Nef is relevant to HIV-associated neurological diseases (HAND) in patients treated with combined antiretroviral therapy because of the protein's role in promoting survival and migration of infected brain macrophages. In this study, we analyzed 2020 HIV Nef sequences derived from 22 different tissues and 31 subjects using a novel computational approach. This approach combines statistical regression and evolved neural networks (ENNs) to classify brain sequences based on the physical and chemical characteristics of functional Nef domains. Based on training, testing, and validation data, the method successfully classified brain Nef sequences at 84.5% and provided informative features for further examination. These included physicochemical features associated with the Src-homology-3 binding domain, the Nef loop (including the AP-2 Binding region), and a cytokine-binding domain. Non-brain sequences from patients with HIV-associated neurological disease were frequently classified as brain, suggesting that the approach could indicate neurological risk using blood-derived virus or for the development of biomarkers for use in assay systems aimed at drug efficacy studies for the treatment of HIV-associated neurological diseases.
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Grötzinger J, Lorenzen I, Düsterhöft S. Molecular insights into the multilayered regulation of ADAM17: The role of the extracellular region. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2088-2095. [PMID: 28571693 DOI: 10.1016/j.bbamcr.2017.05.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/25/2017] [Accepted: 05/26/2017] [Indexed: 12/22/2022]
Abstract
In contrast to many other signalling mechanisms shedding of membrane-anchored proteins is an irreversible process. A Disintegrin And Metalloproteinase (ADAM) 17 is one of the major sheddases involved in a variety of physiological and pathophysiological processes including regeneration, differentiation, and cancer progression. Due to its central role in signalling the shedding activity of ADAM17 is tightly regulated, especially on the cell surface, where shedding events take place. The activity of ADAM17 can be subdivided into a catalytic activity and the actual shedding activity. Whereas the catalytic activity is constitutively present, the shedding activity has to be induced and is tightly controlled to prevent pathological situations induced by the release of its substrates. The regulation of the shedding activity of ADAM17 is multilayered and different regions of the protease are involved. Intriguingly, its extracellular domains play crucial roles in different regulatory mechanisms. We will discuss the role of these domains in the control of ADAM17 activity. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.
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Affiliation(s)
- Joachim Grötzinger
- Institute of Biochemistry, Christian-Albrechts-University, Olshausenstr. 40, 24118 Kiel, Germany.
| | - Inken Lorenzen
- Centre of Biochemistry and Molecular Biology, Structural Biology, Christian-Albrechts-University, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Stefan Düsterhöft
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK
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HIV-1 Nef is released in extracellular vesicles derived from astrocytes: evidence for Nef-mediated neurotoxicity. Cell Death Dis 2017; 8:e2542. [PMID: 28079886 PMCID: PMC5386374 DOI: 10.1038/cddis.2016.467] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/15/2016] [Accepted: 11/18/2016] [Indexed: 12/19/2022]
Abstract
Human immunodeficiency virus-associated neurological disorders (HANDs) affect the majority of AIDS patients and are a significant problem among HIV-1-infected individuals who live longer because of combined anti-retroviral therapies. HIV-1 utilizes a number of viral proteins and subsequent cytokine inductions to unleash its toxicity on neurons. Among HIV-1 viral proteins, Nef is a small protein expressed abundantly in astrocytes of HIV-1-infected brains and has been suggested to have a role in the pathogenesis of HAND. In order to explore its effect in the central nervous system, HIV-1 Nef was expressed in primary human fetal astrocytes (PHFAs) using an adenovirus. Our results revealed that HIV-1 Nef is released in extracellular vesicles (EVs) derived from PHFA cells expressing the protein. Interestingly, HIV-1 Nef release in EVs was enriched significantly when the cells were treated with autophagy activators perifosine, tomaxifen, MG-132, and autophagy inhibitors LY294002 and wortmannin suggesting a novel role of autophagy signaling in HIV-1 Nef release from astrocytes. Next, Nef-carrying EVs were purified from astrocyte cultures and neurotoxic effects on neurons were analyzed. We observed that HIV-1 Nef-containing EVs were readily taken up by neurons as demonstrated by immunocytochemistry and immunoblotting. Furthermore, treatment of neurons with Nef-carrying EVs induced oxidative stress as evidenced by a decrease in glutathione levels. To further investigate its neurotoxic effects, we expressed HIV-1 Nef in primary neurons by adenoviral transduction. Intracellular expression of HIV-1 Nef caused axonal and neurite degeneration of neurons. Furthermore, expression of HIV-1 Nef decreased the levels of phospho-tau while enhancing total tau in primary neurons. In addition, treatment of primary neurons with Nef-carrying EVs suppressed functional neuronal action potential assessed by multielectrode array studies. Collectively, these data suggested that HIV-1 Nef can be a formidable contributor to neurotoxicity along with other factors, which leads to HAND in HIV-1-infected AIDS patients.
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HIV Nef- and Notch1-dependent Endocytosis of ADAM17 Induces Vesicular TNF Secretion in Chronic HIV Infection. EBioMedicine 2016; 13:294-304. [PMID: 27773542 PMCID: PMC5264432 DOI: 10.1016/j.ebiom.2016.10.027] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/11/2016] [Accepted: 10/18/2016] [Indexed: 12/30/2022] Open
Abstract
Tumor necrosis factor (TNF) is a key cytokine in HIV replication and pathogenesis. For reasons that are not entirely clear, the cytokine remains upregulated despite anti-retroviral therapy (ART). Here we demonstrate that HIV Nef induces an alternative TNF secretion mechanism that remains active in chronic infection. Ingestion of Nef-containing plasma extracellular vesicles (pEV) from ART patients by primary immune cells, but also Nef expression, induced intracellular proTNF cleavage and secretion of vesicular TNF endosomes. Key event was the Nef-mediated routing of the TNF-converting enzyme ADAM17 into Rab4 + early endosomes and the Rab27 + secretory pathway. Analysis of lymph-node tissue by multi-epitope-ligand-cartography (MELC) confirmed a vesicular TNF secretion phenotype that co-localized with persistent Nef expression, and implicated Notch1 as an essential co-factor. Surprisingly Notch1 had no transcriptional effect but was required for the endosomal trafficking of ADAM17. We conclude that Nef expression and Nef-containing pEV mobilize TNF from endosomal compartments in acute and chronic infection. Nef/ADAM17 containing extracellular vesicles induce an endosomal TNF secretion type in primary target cells. The mechanism required the shuttling of ADAM17 into Rab4 + endosomal compartments in a Notch1-dependent manner. The mechanism could be demonstrated in tissue by multi-epitope-ligand-cartography (MELC) technology.
Despite antiviral therapy, plasma levels of TNF remain upregulated and likely play a role in many comorbidities seen in chronic HIV infection. We found that this is due to high levels of HIV-induced plasma extracellular vesicles (pEV) containing the TNF processing ADAM17 protease. Interestingly these vesicles induced a different TNF secretion type. Whereas TNF is usually shed from the plasma membrane, pEV mobilized intracellular TNF storage compartments, secreting endosomal vesicles. We could confirm this mechanism analyzing lymph node tissue sections by a novel immunostaining technology. Our report supports our previous publication implying ongoing viral activity despite successful antiretroviral therapy.
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Kay LJ, Smulders-Srinivasan TK, Soundararajan M. Understanding the Multifaceted Role of Human Down Syndrome Kinase DYRK1A. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2016; 105:127-71. [PMID: 27567487 DOI: 10.1016/bs.apcsb.2016.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The dual-specificity tyrosine (Y) phosphorylation-regulated kinase DYRK1A, also known as Down syndrome (DS) kinase, is a dosage-dependent signaling kinase that was originally shown to be highly expressed in DS patients as a consequence of trisomy 21. Although this was evident some time ago, it is only in recent investigations that the molecular roles of DYRK1A in a wide range of cellular processes are becoming increasingly apparent. Since initial knowledge on DYRK1A became evident through minibrain mnb, the Drosophila homolog of DYRK1A, this review will first summarize the scientific reports on minibrain and further expand on the well-established neuronal functions of mammalian and human DYRK1A. Recent investigations across the current decade have provided rather interesting and compelling evidence in establishing nonneuronal functions for DYRK1A, including its role in infection, immunity, cardiomyocyte biology, cancer, and cell cycle control. The latter part of this review will therefore focus in detail on the emerging nonneuronal functions of DYRK1A and summarize the regulatory role of DYRK1A in controlling Tau and α-synuclein. Finally, the emerging role of DYRK1A in Parkinson's disease will be outlined.
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Affiliation(s)
- L J Kay
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - T K Smulders-Srinivasan
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - M Soundararajan
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom.
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Shrivastava S, Trivedi J, Mitra D. Gene expression profiling reveals Nef induced deregulation of lipid metabolism in HIV-1 infected T cells. Biochem Biophys Res Commun 2016; 472:169-74. [PMID: 26915805 DOI: 10.1016/j.bbrc.2016.02.089] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 02/22/2016] [Indexed: 01/11/2023]
Abstract
Human Immunodeficiency Virus-1 (HIV-1) encodes a 27 kDa Negative Factor or Nef protein, which is increasingly proving to be a misnomer. Nef seems to be crucial for AIDS progression as individuals infected with nef-deleted strain of HIV were reported to become Long Term Non Progressors (LTNP). These findings necessitate tracing of Nef's footprint on landscape of cellular transcriptome favoring HIV-1 pathogenesis. We have tried to explore effect of Nef on cellular gene expression profile in conjunction with rest of HIV-1 proteins. Our results show that 237 genes are differentially regulated due to the presence of Nef during infection, which belong to several broad categories like "signaling", "apoptosis", "transcription" and "lipid metabolism" in gene ontology analysis. Furthermore, our results show that Nef causes disruption of lipid content in HIV-1 infected T cells. Molecular inhibitors of lipid metabolism like Atorvastatin and Ranolazine were found to have profound effect on wild type virus as compared to nef-deleted HIV-1. Thus our results suggest that interference in lipid metabolism is a potential mechanism through which Nef contributes in enhancing HIV-1 pathogenesis.
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Affiliation(s)
| | - Jay Trivedi
- National Centre for Cell Science, Pune, 411007, India
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Saribas AS, Khalili K, Sariyer IK. Dysregulation of autophagy by HIV-1 Nef in human astrocytes. Cell Cycle 2015; 14:2899-904. [PMID: 26176554 DOI: 10.1080/15384101.2015.1069927] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Viruses often exploit autophagy, a common cellular process of degradation of damaged proteins, organelles, and pathogens, to avoid destruction. HIV-1 dysregulates this process in several cell types by means of Nef protein. Nef is a small HIV-1 protein which is expressed abundantly in astrocytes of HIV-1-infected brains and has been suggested to have a role in the pathogenesis of HIV-Associated Neurocognitive Disorders (HAND). In order to explore its effect in the CNS with respect to autophagy, HIV-1 Nef was expressed in primary human fetal astrocytes (PHFA) using an adenovirus vector (Ad-Nef). We observed that Nef expression triggered the accumulation of autophagy markers, ATG8/LC3 and p62 (SQSMT1). Similar results were obtained with Bafilomycin A1, an autophagy inhibitor which blocks the fusion of autophagosome to lysosome. Furthermore co-expression of tandem LC3 vector (mRFP-EGFP-LC3) and Ad-Nef in these cells produced mainly yellow puncta (mRFP+, EGFP+) strongly suggesting that autophagosome fusion to lysosome is blocked in PHFA cells in the presence of Nef. Together these data indicate that HIV-1 Nef mimics Bafilomycin A1 and blocks the last step of autophagy thereby helping HIV-1 virus to avoid autophagic degradation in human astrocytes.
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Affiliation(s)
- A Sami Saribas
- a Department of Neuroscience Center for Neurovirology ; Temple University School of Medicine ; Philadelphia , PA USA
| | - Kamel Khalili
- a Department of Neuroscience Center for Neurovirology ; Temple University School of Medicine ; Philadelphia , PA USA
| | - Ilker Kudret Sariyer
- a Department of Neuroscience Center for Neurovirology ; Temple University School of Medicine ; Philadelphia , PA USA
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HIV-1 Myristoylated Nef Treatment of Murine Microglial Cells Activates Inducible Nitric Oxide Synthase, NO2 Production and Neurotoxic Activity. PLoS One 2015; 10:e0130189. [PMID: 26066624 PMCID: PMC4465743 DOI: 10.1371/journal.pone.0130189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 05/17/2015] [Indexed: 12/21/2022] Open
Abstract
Background The potential role of the human immunodeficiency virus-1 (HIV-1) accessory protein Nef in the pathogenesis of neuroAIDS is still poorly understood. Nef is a molecular adapter that influences several cellular signal transduction events and membrane trafficking. In human macrophages, Nef expression induces the production of extracellular factors (e.g. pro-inflammatory chemokines and cytokines) and the recruitment of T cells, thus favoring their infection and its own transfer to uninfected cells via exosomes, cellular protrusions or cell-to-cell contacts. Murine cells are normally not permissive for HIV-1 but, in transgenic mice, Nef is a major disease determinant. Both in human and murine macrophages, myristoylated Nef (myr+Nef) treatment has been shown to activate NF-κB, MAP kinases and interferon responsive factor 3 (IRF-3), thereby inducing tyrosine phosphorylation of signal transducers and activator of transcription (STAT)-1, STAT-2 and STAT-3 through the production of proinflammatory factors. Methodology/Principal Findings We report that treatment of BV-2 murine microglial cells with myr+Nef leads to STAT-1, -2 and -3 tyrosine phosphorylation and upregulates the expression of inducible nitric oxide synthase (iNOS) with production of nitric oxide. We provide evidence that extracellular Nef regulates iNOS expression through NF-κB activation and, at least in part, interferon-β (IFNβ) release that acts in concert with Nef. All of these effects require both myristoylation and a highly conserved acidic cluster in the viral protein. Finally, we report that Nef induces the release of neurotoxic factors in the supernatants of microglial cells. Conclusions These results suggest a potential role of extracellular Nef in promoting neuronal injury in the murine model. They also indicate a possible interplay between Nef and host factors in the pathogenesis of neuroAIDS through the production of reactive nitrogen species in microglial cells.
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