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López-Muñoz AD, Santos JJS, Yewdell JW. Cell surface nucleocapsid protein expression: A betacoronavirus immunomodulatory strategy. Proc Natl Acad Sci U S A 2023; 120:e2304087120. [PMID: 37399385 PMCID: PMC10334784 DOI: 10.1073/pnas.2304087120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 06/08/2023] [Indexed: 07/05/2023] Open
Abstract
We recently reported that SARS-CoV-2 nucleocapsid (N) protein is abundantly expressed on the surface of both infected and neighboring uninfected cells, where it enables activation of Fc receptor-bearing immune cells with anti-N antibodies (Abs) and inhibits leukocyte chemotaxis by binding chemokines (CHKs). Here, we extend these findings to N from the common cold human coronavirus (HCoV)-OC43, which is also robustly expressed on the surface of infected and noninfected cells by binding heparan sulfate/heparin (HS/H). HCoV-OC43 N binds with high affinity to the same set of 11 human CHKs as SARS-CoV-2 N, but also to a nonoverlapping set of six cytokines. As with SARS-CoV-2 N, HCoV-OC43 N inhibits CXCL12β-mediated leukocyte migration in chemotaxis assays, as do all highly pathogenic and common cold HCoV N proteins. Together, our findings indicate that cell surface HCoV N plays important evolutionarily conserved roles in manipulating host innate immunity and as a target for adaptive immunity.
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Affiliation(s)
- Alberto Domingo López-Muñoz
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases National Institutes of Health, Bethesda, MD20892
| | - Jefferson J. S. Santos
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases National Institutes of Health, Bethesda, MD20892
| | - Jonathan W. Yewdell
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases National Institutes of Health, Bethesda, MD20892
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2
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Datta G, Miller NM, Chen X. 17⍺-Estradiol Protects against HIV-1 Tat-Induced Endolysosome Dysfunction and Dendritic Impairments in Neurons. Cells 2023; 12:813. [PMID: 36899948 PMCID: PMC10000619 DOI: 10.3390/cells12050813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/03/2023] [Accepted: 03/04/2023] [Indexed: 03/08/2023] Open
Abstract
HIV-1 Tat continues to play an important role in the development of HIV-associated neurocognitive disorders (HAND), which persist in 15-55% of people living with HIV even with virological control. In the brain, Tat is present on neurons, where Tat exerts direct neuronal damaging effects by, at least in part, disrupting endolysosome functions, a pathological feature present in HAND. In this study, we determined the protective effects of 17α-estradiol (17αE2), the predominant form of estrogen in the brain, against Tat-induced endolysosome dysfunction and dendritic impairment in primary cultured hippocampal neurons. We demonstrated that pre-treatment with 17αE2 protected against Tat-induced endolysosome dysfunction and reduction in dendritic spine density. Estrogen receptor alpha (ERα) knockdown impairs the ability of 17αE2 to protect against Tat-induced endolysosome dysfunction and reduction in dendritic spine density. Furthermore, over-expressing an ERα mutant that fails to localize on endolysosomes impairs 17αE2's protective effects against Tat-induced endolysosome dysfunction and reduction in dendritic spine density. Our findings demonstrate that 17αE2 protects against Tat-induced neuronal injury via a novel ERα-mediated and endolysosome-dependent pathway, and such a finding might lead to the development of novel adjunct therapeutics against HAND.
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Affiliation(s)
| | | | - Xuesong Chen
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
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3
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López-Muñoz AD, Santos JJ, Yewdell JW. Cell Surface Nucleocapsid Protein Expression: A Betacoronavirus Immunomodulatory Strategy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.24.529952. [PMID: 36993159 PMCID: PMC10054960 DOI: 10.1101/2023.02.24.529952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
We recently reported that SARS-CoV-2 Nucleocapsid (N) protein is abundantly expressed on the surface of both infected and neighboring uninfected cells, where it enables activation of Fc receptor-bearing immune cells with anti-N antibodies (Abs) and inhibits leukocyte chemotaxis by binding chemokines (CHKs). Here, we extend these findings to N from the seasonal human coronavirus (HCoV)-OC43, which is also robustly expressed on the surface of infected and non-infected cells by binding heparan-sulfate/heparin (HS/H). HCoV-OC43 N binds with high affinity to the same set of 11 human CHKs as SARS-CoV-2 N, but also to a non-overlapping set of 6 cytokines (CKs). As with SARS-CoV-2 N, HCoV-OC43 N inhibits CXCL12β-mediated leukocyte migration in chemotaxis assays, as do all highly pathogenic and endemic HCoV N proteins. Together, our findings indicate that cell surface HCoV N plays important evolutionary conserved roles in manipulating host innate immunity and as a target for adaptive immunity.
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4
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Cafaro A, Ensoli B. HIV-1 therapeutic vaccines in clinical development to intensify or replace antiretroviral therapy: the promising results of the Tat vaccine. Expert Rev Vaccines 2022; 21:1243-1253. [PMID: 35695268 DOI: 10.1080/14760584.2022.2089119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Upon the introduction of the combination antiretroviral therapy (cART), HIV infection has become a chronic disease. However, cART is unable to eradicate the virus and fails to restore the CD4 counts in about 30% of the treated individuals. Furthermore, treatment is life-long, and it does not protect from morbidities typically observed in the elderly. Therapeutic vaccines represent the most cost-effective intervention to intensify or replace cART. AREAS COVERED Here, we briefly discuss the obstacles to the development and evaluation of the efficacy of therapeutic vaccines and review recent approaches evaluated in clinical trials. EXPERT OPINION Although vaccines were generally safe and immunogenic, evidence of efficacy was negligible or marginal in most trials. A notable exception is the therapeutic Tat vaccine approach showing promising results of cART intensification, with CD4 T-cell increase and proviral load reduction beyond those afforded by cART alone. Rationale and evidence in support of choosing Tat as the vaccine target are thoroughly discussed.
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Affiliation(s)
- Aurelio Cafaro
- National HIV/AIDS Research Center, Istituto Superiore Di Sanità, Rome, Italy
| | - Barbara Ensoli
- National HIV/AIDS Research Center, Istituto Superiore Di Sanità, Rome, Italy
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5
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Maricchiolo E, Panfili E, Pompa A, De Marchis F, Bellucci M, Pallotta MT. Unconventional Pathways of Protein Secretion: Mammals vs. Plants. Front Cell Dev Biol 2022; 10:895853. [PMID: 35573696 PMCID: PMC9096121 DOI: 10.3389/fcell.2022.895853] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/13/2022] [Indexed: 01/08/2023] Open
Abstract
In eukaryotes, many proteins contain an N-terminal signal peptide that allows their translocation into the endoplasmic reticulum followed by secretion outside the cell according to the classical secretory system. However, an increasing number of secreted proteins lacking the signal peptide sequence are emerging. These proteins, secreted in several alternative ways collectively known as unconventional protein secretion (UPS) pathways, exert extracellular functions including cell signaling, immune modulation, as well as moonlighting activities different from their well-described intracellular functions. Pathways for UPS include direct transfer across the plasma membrane, secretion from endosomal/multivesicular body-related components, release within plasma membrane-derived microvesicles, or use of elements of autophagy. In this review we describe the mammals and plants UPS pathways identified so far highlighting commonalities and differences.
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Affiliation(s)
- Elisa Maricchiolo
- Section of Biological and Biotechnological Sciences, Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Eleonora Panfili
- Section of Pharmacology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Andrea Pompa
- Section of Biological and Biotechnological Sciences, Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Francesca De Marchis
- Institute of Biosciences and Bioresources, National Research Council of Italy, Perugia, Italy
| | - Michele Bellucci
- Institute of Biosciences and Bioresources, National Research Council of Italy, Perugia, Italy
- *Correspondence: Michele Bellucci, ; Maria Teresa Pallotta,
| | - Maria Teresa Pallotta
- Section of Pharmacology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
- *Correspondence: Michele Bellucci, ; Maria Teresa Pallotta,
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6
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Unconventional secretion mediated by direct protein self-translocation across the plasma membranes of mammalian cells. Trends Biochem Sci 2022; 47:699-709. [PMID: 35490075 DOI: 10.1016/j.tibs.2022.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/22/2022] [Accepted: 04/01/2022] [Indexed: 12/17/2022]
Abstract
In recent years, a surprisingly complex picture emerged about endoplasmic reticulum (ER)/Golgi-independent secretory pathways, and several routes have been discovered that differ with regard to their molecular mechanisms and machineries. Fibroblast growth factor 2 (FGF2) is secreted by a pathway of unconventional protein secretion (UPS) that is based on direct self-translocation across the plasma membrane. Building on previous research, a component of this process has been identified to be glypican-1 (GPC1), a GPI-anchored heparan sulfate proteoglycan located on cell surfaces. These findings not only shed light on the molecular mechanism underlying this process but also reveal an intimate relationship between FGF2 and GPC1 that might be of critical relevance for the prominent roles they both have in tumor progression and metastasis.
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Lolicato F, Nickel W. A Role for Liquid-Ordered Plasma Membrane Nanodomains Coordinating the Unconventional Secretory Pathway of Fibroblast Growth Factor 2? Front Cell Dev Biol 2022; 10:864257. [PMID: 35433697 PMCID: PMC9010882 DOI: 10.3389/fcell.2022.864257] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/18/2022] [Indexed: 11/22/2022] Open
Abstract
Fibroblast growth factor 2 (FGF2) is a tumor cell survival factor that belongs to a subgroup of extracellular proteins lacking N-terminal signal peptides. Whereas this phenomenon was already recognized in the early 1990s, detailed insights into the molecular mechanisms underlying alternative pathways of protein secretion from eukaryotic cells were obtained only recently. Today, we know about a number of alternative secretory mechanisms, collectively termed unconventional protein secretion (UPS). FGF2 belongs to a subgroup of cargo proteins secreted by direct translocation across the plasma membrane. This feature has been classified as type I UPS and is shared with other unconventionally secreted proteins, such as HIV-Tat and Tau. FGF2 translocation across the membrane is initiated through sequential interactions with the Na,K-ATPase, Tec kinase, and phosphoinositide PI(4,5)P2 at the inner plasma membrane leaflet. Whereas the first two are auxiliary factors of this pathway, the interaction of FGF2 with PI(4,5)P2 triggers the core mechanism of FGF2 membrane translocation. It is based on a lipidic membrane pore that is formed by PI(4,5)P2-induced oligomerization of FGF2. Membrane-inserted FGF2 oligomers are recognized as translocation intermediates that are resolved at the outer plasma membrane leaflet by glypican-1, a heparan sulfate proteoglycan that captures and disassembles FGF2 oligomers on cell surfaces. Here, we discuss recent findings suggesting the molecular machinery mediating FGF2 membrane translocation to be highly organized in liquid-ordered plasma membrane nanodomains, the core process underlying this unusual pathway of protein secretion.
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Affiliation(s)
- Fabio Lolicato
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg, Germany
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8
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Khan N, Halcrow PW, Afghah Z, Baral A, Geiger J, Chen X. HIV-1 Tat endocytosis and retention in endolysosomes affects HIV-1 Tat-induced LTR transactivation in astrocytes. FASEB J 2022; 36:e22184. [PMID: 35113458 PMCID: PMC9627655 DOI: 10.1096/fj.202101722r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/13/2022] [Accepted: 01/18/2022] [Indexed: 11/11/2022]
Abstract
The presence of latent HIV-1 reservoirs in the periphery and brain represents a major obstacle to curing HIV-1 infection. As an essential protein for HIV-1 viral replication, HIV-1 Tat, mostly intracellular, has been implicated in latent HIV-1 infection. From HIV-1 infected cells, HIV-1 Tat is actively secreted and bystander cells uptake the released Tat whereupon it is endocytosed and internalized into endolysosomes. However, to activate the HIV-1 LTR promoter and increase HIV-1 replication, HIV-1 Tat must first escape from the endolysosomes and then enter the nucleus. Here, we tested the hypothesis that HIV-1 Tat can accumulate in endolysosomes and contribute to the activation of latent HIV-1 in astrocytes. Using U87MG astrocytoma cells expressing HIV-1 LTR-driven luciferase and primary human astrocytes we found that exogenous HIV-1 Tat enters endolysosomes, resides in endolysosomes for extended periods of time, and induces endolysosome de-acidification as well as enlargement. The weak base chloroquine promoted the release of HIV-1 Tat from endolysosomes and induced HIV-1 LTR transactivation. Similar results were observed by activating endolysosome Toll-like receptor 3 (TLR3) and TLR7/8. Conversely, pharmacological block of TLRs and knocking down expression levels of TLR3 and TLR7, but not TLR8, prevented endolysosome leakage and attenuated HIV-1 Tat-mediated HIV-1 LTR transactivation. Our findings suggest that HIV-1 Tat accumulation in endolysosomes may play an important role in controlling HIV-1 transactivation.
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Affiliation(s)
- Nabab Khan
- Department of Biomedical Sciences University of North Dakota School of Medicine and Health Sciences Grand Forks North Dakota USA
| | - Peter W. Halcrow
- Department of Biomedical Sciences University of North Dakota School of Medicine and Health Sciences Grand Forks North Dakota USA
| | - Zahra Afghah
- Department of Biomedical Sciences University of North Dakota School of Medicine and Health Sciences Grand Forks North Dakota USA
| | - Aparajita Baral
- Department of Biomedical Sciences University of North Dakota School of Medicine and Health Sciences Grand Forks North Dakota USA
| | - Jonathan D. Geiger
- Department of Biomedical Sciences University of North Dakota School of Medicine and Health Sciences Grand Forks North Dakota USA
| | - Xuesong Chen
- Department of Biomedical Sciences University of North Dakota School of Medicine and Health Sciences Grand Forks North Dakota USA
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9
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Ratnapriya S, Harris M, Chov A, Herbert ZT, Vrbanac V, Deruaz M, Achuthan V, Engelman AN, Sodroski J, Herschhorn A. Intra- and extra-cellular environments contribute to the fate of HIV-1 infection. Cell Rep 2021; 36:109622. [PMID: 34469717 PMCID: PMC8463096 DOI: 10.1016/j.celrep.2021.109622] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 06/07/2021] [Accepted: 08/06/2021] [Indexed: 11/18/2022] Open
Abstract
HIV-1 entry into host cells leads to one of the following three alternative fates: (1) HIV-1 elimination by restriction factors, (2) establishment of HIV-1 latency, or (3) active viral replication in target cells. Here, we report the development of an improved system for monitoring HIV-1 fate at single-cell and population levels and show the diverse applications of this system to study specific aspects of HIV-1 fate in different cell types and under different environments. An analysis of the transcriptome of infected, primary CD4+ T cells that support alternative fates of HIV-1 identifies differential gene expression signatures in these cells. Small molecules are able to selectively target cells that support viral replication with no significant effect on viral latency. In addition, HIV-1 fate varies in different tissues following infection of humanized mice in vivo. Altogether, these studies indicate that intra- and extra-cellular environments contribute to the fate of HIV-1 infection.
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Affiliation(s)
- Sneha Ratnapriya
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Miranda Harris
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Angela Chov
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Zachary T Herbert
- Molecular Biology Core Facilities, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Vladimir Vrbanac
- Humanized Immune System Mouse Program, Ragon Institute of MGH, MIT and Harvard, and Center for Immunology and Inflammatory Disease, Cambridge, MA 02139, USA
| | - Maud Deruaz
- Humanized Immune System Mouse Program, Ragon Institute of MGH, MIT and Harvard, and Center for Immunology and Inflammatory Disease, Cambridge, MA 02139, USA
| | - Vasudevan Achuthan
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA.
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10
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Ali A, Mishra R, Kaur H, Chandra Banerjea A. HIV-1 Tat: An update on transcriptional and non-transcriptional functions. Biochimie 2021; 190:24-35. [PMID: 34242726 DOI: 10.1016/j.biochi.2021.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 06/24/2021] [Accepted: 07/01/2021] [Indexed: 01/05/2023]
Abstract
Over the past decades, much have been learned about HIV-1 virus and its molecular strategies for pathogenesis. However, HIV-1 still remains an enigmatic virus, particularly because of its unique proteins. Establishment of latency and reactivation is still a puzzling question and various temporal and spatial dynamics between HIV-1 proteins itself have given us new way of thinking about its pathogenesis. HIV-1 replication depends on Tat which is a small unstructured protein and subjected to various post-translational modifications for its myriad of functions. HIV-1 Tat protein modulates the functions of various strategic cellular pathways like proteasomal machinery and inflammatory pathways to aid in HIV-1 pathogenesis. Many of the recent findings have shown that Tat is associated with exosomes, cleared from HIV-1 infected cells through its degradation by diverse routes ranging from lysosomal to proteasomal pathways. HIV-1 Tat was also found to be associated with other HIV-1 proteins including Vpr, Nef, Nucleocapsid (NC) and Rev. Interaction of Tat with Vpr and Nef increases its transactivation function, whereas, interaction of Tat with NC or Rev leads to Tat protein degradation and hence suppression of Tat functions. Research in the recent years has established that Tat is not only important for HIV-1 promoter transactivation and virus replication but also modulating multiple cellular and molecular functions leading to HIV-1 pathogenicity. In this review we discussed various transcriptional and non-transcriptional HIV-1 Tat functions which modulate host cell metabolism during HIV-1 pathogenesis.
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Affiliation(s)
- Amjad Ali
- Virology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India; Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
| | - Ritu Mishra
- Virology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Harsimrut Kaur
- Department of Chemistry and Biochemistry, School of Basic Sciences and Research, Sharda University, Knowledge Park III, Greater Noida, Uttar Pradesh, 201310, India.
| | - Akhil Chandra Banerjea
- Virology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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11
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Cirino TJ, McLaughlin JP. Mini review: Promotion of substance abuse in HIV patients: Biological mediation by HIV-1 Tat protein. Neurosci Lett 2021; 753:135877. [PMID: 33838257 DOI: 10.1016/j.neulet.2021.135877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/28/2021] [Accepted: 03/30/2021] [Indexed: 11/29/2022]
Abstract
Despite successful viral suppression by combinatorial anti-retroviral therapy, HIV infection continues to negatively impact the quality of life of patients by promoting neuropathy and HIV-Associated Neurocognitive Disorders (HAND), where substance use disorder (SUD) is highly comorbid and known to worsen health outcomes. While substance abuse exacerbates the progression of HIV, emerging evidence also suggests the virus may potentiate the rewarding effect of abused substances. As HIV does not infect neurons, these effects are theorized to be mediated by viral proteins. Key among these proteins are HIV-1 Tat, which can continue to be produced under viral suppression in patients. This review will recap the behavioral evidence for HIV-1 Tat mediation of a potentiation of cocaine, opioid and alcohol reward, and explore the neurochemical dysfunction associated by Tat as potential mechanisms underlying changes in reward. Targeting rampant oxidative stress, inflammation and excitotoxicity associated with HIV and Tat protein exposure may prove useful in combating persistent substance abuse comorbid with HIV in the clinic.
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Affiliation(s)
- Thomas J Cirino
- Department of Neurology, School of Medicine, University of California at San Francisco, San Francisco, CA, 94158, USA
| | - Jay P McLaughlin
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA.
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12
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Newman RA, Sastry KJ, Arav-Boger R, Cai H, Matos R, Harrod R. Antiviral Effects of Oleandrin. J Exp Pharmacol 2020; 12:503-515. [PMID: 33262663 PMCID: PMC7686471 DOI: 10.2147/jep.s273120] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/25/2020] [Indexed: 12/13/2022] Open
Abstract
Over the past 15 years, investigators have reported on the utility and safety of cardiac glycosides for numerous health benefits including those as treatments for malignant disease, stroke-mediated ischemic injury and certain neurodegenerative diseases. In addition to those, there is a growing body of evidence for novel antiviral effects of selected cardiac glycoside molecules. One unique cardiac glycoside, oleandrin derived from Nerium oleander, has been reported to have antiviral activity specifically against 'enveloped' viruses including HIV and HTLV-1. Importantly, a recent publication has presented in vitro evidence for oleandrin's ability to inhibit production of infectious virus particles when used for treatment prior to, as well as after infection by SARS-CoV-2/COVID-19. This review will highlight the known in vitro antiviral effects of oleandrin as well as present previously unpublished effects of this novel cardiac glycoside against Ebola virus, Cytomegalovirus, and Herpes simplex viruses.
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Affiliation(s)
- Robert A Newman
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77054, USA.,Phoenix Biotechnology, Inc, San Antonio, TX 78217, USA
| | - K Jagannadha Sastry
- Departments of Thoracic, Head and Neck Medical Oncology and Veterinary Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ravit Arav-Boger
- Division of Infectious Diseases, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Hongyi Cai
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Robert Harrod
- Department of Biological Sciences, the Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, Dallas, TX 75275, USA
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13
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Pallotta MT, Nickel W. FGF2 and IL-1β – explorers of unconventional secretory pathways at a glance. J Cell Sci 2020; 133:133/21/jcs250449. [DOI: 10.1242/jcs.250449] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
ABSTRACT
Fibroblast growth factor 2 (FGF2) and interleukin 1β (IL-1β) were among the earliest examples of a subclass of proteins with extracellular functions that were found to lack N-terminal secretory signal peptides and were shown to be secreted in an ER- and Golgi-independent manner. Many years later, a number of alternative secretory pathways have been discovered, processes collectively termed unconventional protein secretion (UPS). In the course of these studies, unconventional secretion of FGF2 and IL-1β were found to be based upon distinct pathways, mechanisms and molecular machineries. Following a concise introduction into various pathways mediating unconventional secretion and transcellular spreading of proteins, this Cell Science at a Glance poster article aims at a focused analysis of recent key discoveries providing unprecedented detail about the molecular mechanisms and machineries driving FGF2 and IL-1β secretion. These findings are also highly relevant for other unconventionally secreted cargoes that, like FGF2 and IL1β, exert fundamental biological functions in biomedically relevant processes, such as tumor-induced angiogenesis and inflammation.
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Affiliation(s)
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg 69120, Germany
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14
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Merezhko M, Uronen RL, Huttunen HJ. The Cell Biology of Tau Secretion. Front Mol Neurosci 2020; 13:569818. [PMID: 33071756 PMCID: PMC7539664 DOI: 10.3389/fnmol.2020.569818] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/26/2020] [Indexed: 12/27/2022] Open
Abstract
The progressive accumulation and spread of misfolded tau protein in the nervous system is the hallmark of tauopathies, progressive neurodegenerative diseases with only symptomatic treatments available. A growing body of evidence suggests that spreading of tau pathology can occur via cell-to-cell transfer involving secretion and internalization of pathological forms of tau protein followed by templated misfolding of normal tau in recipient cells. Several studies have addressed the cell biological mechanisms of tau secretion. It now appears that instead of a single mechanism, cells can secrete tau via three coexisting pathways: (1) translocation through the plasma membrane; (2) membranous organelles-based secretion; and (3) ectosomal shedding. The relative importance of these pathways in the secretion of normal and pathological tau is still elusive, though. Moreover, glial cells contribute to tau propagation, and the involvement of different cell types, as well as different secretion pathways, complicates the understanding of prion-like propagation of tauopathy. One of the important regulators of tau secretion in neuronal activity, but its mechanistic connection to tau secretion remains unclear and may involve all three secretion pathways of tau. This review article summarizes recent advancements in the field of tau secretion with an emphasis on cell biological aspects of the secretion process and discusses the role of neuronal activity and glial cells in the spread of pathological forms of tau.
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Affiliation(s)
- Maria Merezhko
- Neuroscience Center, HiLIFE, University of Helsinki, Helsinki, Finland
| | | | - Henri J Huttunen
- Neuroscience Center, HiLIFE, University of Helsinki, Helsinki, Finland
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15
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Alphavirus Replication: The Role of Cardiac Glycosides and Ion Concentration in Host Cells. BIOMED RESEARCH INTERNATIONAL 2020; 2020:2813253. [PMID: 32461975 PMCID: PMC7232666 DOI: 10.1155/2020/2813253] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/31/2020] [Accepted: 04/15/2020] [Indexed: 01/07/2023]
Abstract
Alphaviruses are arthropod-borne viruses that can cause fever, rash, arthralgias, and encephalitis. The mosquito species Aedes aegypti and Aedes albopictus are the most frequent transmitters of alphaviruses. There are no effective vaccines or specific antivirals available for the treatment of alphavirus-related infections. Interestingly, changes in ion concentration in host cells have been characterized as critical regulators of the alphavirus life cycle, including fusion with the host cell, glycoprotein trafficking, genome translation, and viral budding. Cardiac glycosides, which are classical inhibitors of the Na+ K+ ATPase (NKA), can inhibit alphavirus replication although their mechanisms of action are poorly understood. Nonetheless, results from multiple studies suggest that inhibition of NKA may be a suitable strategy for the development of alphavirus-specific antiviral treatments. This review is aimed at exploring the role of changes in ion concentration during alphavirus replication and at considering the possibility of NKA as a potential therapeutic target for antiviral drugs.
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16
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Abstract
The full length of HIV/R7/E−/GFP integrated in the J-Lat 10.6 cell line was sequenced in this study. The single copy of the integrated virus, including the breakpoints from the human chromosome to the provirus, was amplified by two separate PCRs. A 10,200-bp genome sequence was acquired, analyzed, and deposited in GenBank. The full length of HIV/R7/E−/GFP integrated in the J-Lat 10.6 cell line was sequenced in this study. The single copy of the integrated virus, including the breakpoints from the human chromosome to the provirus, was amplified by two separate PCRs. A 10,200-bp genome sequence was acquired, analyzed, and deposited in GenBank.
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17
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Influenza A virus PB1‐F2 protein: An ambivalent innate immune modulator and virulence factor. J Leukoc Biol 2020; 107:763-771. [DOI: 10.1002/jlb.4mr0320-206r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 03/23/2020] [Accepted: 03/24/2020] [Indexed: 12/14/2022] Open
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18
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Legrand C, Saleppico R, Sticht J, Lolicato F, Müller HM, Wegehingel S, Dimou E, Steringer JP, Ewers H, Vattulainen I, Freund C, Nickel W. The Na,K-ATPase acts upstream of phosphoinositide PI(4,5)P 2 facilitating unconventional secretion of Fibroblast Growth Factor 2. Commun Biol 2020; 3:141. [PMID: 32214225 PMCID: PMC7096399 DOI: 10.1038/s42003-020-0871-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 03/02/2020] [Indexed: 12/19/2022] Open
Abstract
FGF2 is a tumor cell survival factor that is exported from cells by an ER/Golgi-independent secretory pathway. This unconventional mechanism of protein secretion is based on direct translocation of FGF2 across the plasma membrane. The Na,K-ATPase has previously been shown to play a role in this process, however, the underlying mechanism has remained elusive. Here, we define structural elements that are critical for a direct physical interaction between FGF2 and the α1 subunit of the Na,K-ATPase. In intact cells, corresponding FGF2 mutant forms were impaired regarding both recruitment at the inner plasma membrane leaflet and secretion. Ouabain, a drug that inhibits both the Na,K-ATPase and FGF2 secretion, was found to impair the interaction of FGF2 with the Na,K-ATPase in cells. Our findings reveal the Na,K-ATPase as the initial recruitment factor for FGF2 at the inner plasma membrane leaflet being required for efficient membrane translocation of FGF2 to cell surfaces. Legrand et al. identify two lysine residues on molecular surface of Fibroblast Growth Factor 2 (FGF2) essential for its interaction with α1 subunit of the Na,K-ATPase. They further conclude that this interaction precedes interaction of the FGF2 with PI(4,5)P2 and facilitates its unconventional secretion across the membrane, which is impaired by Ouabain, an Na,K-ATPase inhibitor.
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Affiliation(s)
- Cyril Legrand
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Roberto Saleppico
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Jana Sticht
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany.,Core Facility BioSupraMol, Freie Universität Berlin, Berlin, Germany
| | - Fabio Lolicato
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany.,Department of Physics, University of Helsinki, FL-00014, Helsinki, Finland.,Computational Physics Laboratory, Tampere University, Fl-33100, Tampere, Finland
| | - Hans-Michael Müller
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Sabine Wegehingel
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Eleni Dimou
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Julia P Steringer
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Helge Ewers
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Ilpo Vattulainen
- Department of Physics, University of Helsinki, FL-00014, Helsinki, Finland.,Computational Physics Laboratory, Tampere University, Fl-33100, Tampere, Finland
| | - Christian Freund
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany.
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19
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Khan N, Halcrow PW, Lakpa KL, Afghah Z, Miller NM, Dowdy SF, Geiger JD, Chen X. Two-pore channels regulate Tat endolysosome escape and Tat-mediated HIV-1 LTR transactivation. FASEB J 2020; 34:4147-4162. [PMID: 31950548 PMCID: PMC7079041 DOI: 10.1096/fj.201902534r] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/10/2019] [Accepted: 01/02/2020] [Indexed: 12/25/2022]
Abstract
HIV-1 Tat is essential for HIV-1 replication and appears to play an important role in the pathogenesis of HIV-associated neurological complications. Secreted from infected or transfected cells, Tat has the extraordinary ability to cross the plasma membrane. In the brain, Tat can be taken up by CNS cells via receptor-mediated endocytosis. Following endocytosis and its internalization into endolysosomes, Tat must be released in order for it to activate the HIV-1 LTR promoter and facilitate HIV-1 viral replication in the nucleus. However, the underlying mechanisms whereby Tat escapes endolysosomes remain unclear. Because Tat disrupts intracellular calcium homeostasis, we investigated the involvement of calcium in Tat endolysosome escape and subsequent LTR transactivation. We demonstrated that chelating endolysosome calcium with high-affinity rhodamine-dextran or chelating cytosolic calcium with BAPTA-AM attenuated Tat endolysosome escape and LTR transactivation. Significantly, we demonstrated that pharmacologically blocking and knocking down the endolysosome-resident two-pore channels (TPCs) attenuated Tat endolysosome escape and LTR transactivation. This calcium-mediated effect appears to be selective for TPCs because knocking down TRPML1 calcium channels was without effect. Our findings suggest that calcium released from TPCs is involved in Tat endolysosome escape and subsequent LTR transactivation. TPCs might represent a novel therapeutic target against HIV-1 infection and HIV-associated neurological complications.
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Affiliation(s)
- Nabab Khan
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine and Health SciencesGrand ForksNDUSA
| | - Peter W. Halcrow
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine and Health SciencesGrand ForksNDUSA
| | - Koffi L. Lakpa
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine and Health SciencesGrand ForksNDUSA
| | - Zahra Afghah
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine and Health SciencesGrand ForksNDUSA
| | - Nicole M. Miller
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine and Health SciencesGrand ForksNDUSA
| | - Steven F. Dowdy
- Department of Cellular and Molecular MedicineUniversity of California San Diego (UCSD) School of MedicineLa JollaCAUSA
| | - Jonathan D. Geiger
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine and Health SciencesGrand ForksNDUSA
| | - Xuesong Chen
- Department of Biomedical SciencesUniversity of North Dakota School of Medicine and Health SciencesGrand ForksNDUSA
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20
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Unconventional Secretion Mediates the Trans-cellular Spreading of Tau. Cell Rep 2019; 23:2039-2055. [PMID: 29768203 DOI: 10.1016/j.celrep.2018.04.056] [Citation(s) in RCA: 169] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 01/19/2018] [Accepted: 04/13/2018] [Indexed: 12/12/2022] Open
Abstract
The progressive deposition of misfolded hyperphosphorylated tau is a pathological hallmark of tauopathies, including Alzheimer's disease. However, the underlying molecular mechanisms governing the intercellular spreading of tau species remain elusive. Here, we show that full-length soluble tau is unconventionally secreted by direct translocation across the plasma membrane. Increased secretion is favored by tau hyperphosphorylation, which provokes microtubule detachment and increases the availability of free protein inside cells. Using a series of binding assays, we show that free tau interacts with components enriched at the inner leaflet of the plasma membrane, finally leading to its translocation across the plasma membrane mediated by sulfated proteoglycans. We provide further evidence that secreted soluble tau species spread trans-cellularly and are sufficient for the induction of intracellular tau aggregation in adjacent cells. Our study demonstrates the mechanistic details of tau secretion and provides insights into the initiation and progression of tau pathology.
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21
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Guerrero A, Herranz N, Sun B, Wagner V, Gallage S, Guiho R, Wolter K, Pombo J, Irvine EE, Innes AJ, Birch J, Glegola J, Manshaei S, Heide D, Dharmalingam G, Harbig J, Olona A, Behmoaras J, Dauch D, Uren AG, Zender L, Vernia S, Martínez-Barbera JP, Heikenwalder M, Withers DJ, Gil J. Cardiac glycosides are broad-spectrum senolytics. Nat Metab 2019; 1:1074-1088. [PMID: 31799499 PMCID: PMC6887543 DOI: 10.1038/s42255-019-0122-z] [Citation(s) in RCA: 179] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 09/10/2019] [Indexed: 02/06/2023]
Abstract
Senescence is a cellular stress response that results in the stable arrest of old, damaged or preneoplastic cells. Oncogene-induced senescence is tumor suppressive but can also exacerbate tumorigenesis through the secretion of pro-inflammatory factors from senescent cells. Drugs that selectively kill senescent cells, termed senolytics, have proved beneficial in animal models of many age-associated diseases. Here, we show that the cardiac glycoside, ouabain, is a senolytic agent with broad activity. Senescent cells are sensitized to ouabain-induced apoptosis, a process mediated in part by induction of the pro-apoptotic Bcl2-family protein NOXA. We show that cardiac glycosides synergize with anti-cancer drugs to kill tumor cells and eliminate senescent cells that accumulate after irradiation or in old mice. Ouabain also eliminates senescent preneoplastic cells. Our findings suggest that cardiac glycosides may be effective anti-cancer drugs by acting through multiple mechanism. Given the broad range of senescent cells targeted by cardiac glycosides their use against age-related diseases warrants further exploration.
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Affiliation(s)
- Ana Guerrero
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Nicolás Herranz
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Bin Sun
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Verena Wagner
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Suchira Gallage
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
- Division of Chronic Inflammation and Cancer, German Cancer Research Centre, Heidelberg, Germany
| | - Romain Guiho
- Developmental Biology and Cancer Programme, Birth Defects Research Centre, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Katharina Wolter
- Department of Internal Medicine VIII, University Hospital Tübingen, Tübingen, Germany
- Department of Physiology I, Institute of Physiology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Joaquim Pombo
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Elaine E Irvine
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Andrew J Innes
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Jodie Birch
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Justyna Glegola
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Saba Manshaei
- Developmental Biology and Cancer Programme, Birth Defects Research Centre, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Danijela Heide
- Division of Chronic Inflammation and Cancer, German Cancer Research Centre, Heidelberg, Germany
| | - Gopuraja Dharmalingam
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Jule Harbig
- Department of Internal Medicine VIII, University Hospital Tübingen, Tübingen, Germany
- Department of Physiology I, Institute of Physiology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Antoni Olona
- Centre for Inflammatory Disease, Imperial College London, Hammersmith Hospital, London, UK
| | - Jacques Behmoaras
- Centre for Inflammatory Disease, Imperial College London, Hammersmith Hospital, London, UK
| | - Daniel Dauch
- Department of Internal Medicine VIII, University Hospital Tübingen, Tübingen, Germany
- Department of Physiology I, Institute of Physiology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Anthony G Uren
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Lars Zender
- Department of Internal Medicine VIII, University Hospital Tübingen, Tübingen, Germany
- Department of Physiology I, Institute of Physiology, Eberhard Karls University Tübingen, Tübingen, Germany
- Translational Gastrointestinal Oncology Group, German Consortium for Translational Cancer Research, German Cancer Research Center, Heidelberg, Germany
| | - Santiago Vernia
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Juan Pedro Martínez-Barbera
- Developmental Biology and Cancer Programme, Birth Defects Research Centre, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Mathias Heikenwalder
- Division of Chronic Inflammation and Cancer, German Cancer Research Centre, Heidelberg, Germany
| | - Dominic J Withers
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Jesús Gil
- MRC London Institute of Medical Sciences, London, UK.
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK.
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22
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BK channels regulate extracellular Tat-mediated HIV-1 LTR transactivation. Sci Rep 2019; 9:12285. [PMID: 31439883 PMCID: PMC6706582 DOI: 10.1038/s41598-019-48777-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 08/05/2019] [Indexed: 01/22/2023] Open
Abstract
HIV-1 Tat is essential for HIV-1 replication and plays an important role in latent HIV-1 infection, HIV-1 associated neurological complication, and other HIV-1 comorbidities. Secreted from HIV-1 infected or transfected cells, Tat can be up-taken into cells by receptor-mediated endocytosis and internalized into endolysosomes. To reach nucleus where it can facilitate HIV-1 viral replication, exogenous Tat has to escape the degradation by endolysosomes. Because of findings that endolysosome de-acidification with, for example, the weak-base anti-malarial drug chloroquine prevents exogenous Tat degradation and enhances the amount of Tat available to activate HIV-1 LTR, we hypothesize that acidifying endolysosomes may enhance Tat degradation in endolysosomes and restrict LTR transactivation. Here, we determined the involvement of endolysosome-resident transient receptor potential mucolipin 1 channel (TRPML1) and the big conductance Ca2+-activated potassium (BK) channel in regulating endolysosome pH, as well as Tat-mediated HIV-1 LTR transactivation in U87MG cells stably integrated with HIV-1 LTR luciferase reporter. Activating TRPML1 channels with ML-SA1 acidified endolysosomes and restricted Tat-mediated HIV-1 LTR transactivation. These effects of ML-SA1 appeared to be mediated through activation of BK channels, because the effects of ML-SA1 on Tat-mediated HIV-1 LTR transactivation were blocked using pharmacological inhibitors or shRNA knock-down of BK channels. On the other hand, activating TRPML1 and BK channels enhanced cellular degradation of exogenous Tat. These results suggest that acidifying endolysosomes by activating TRPML1 or BK channels may provide therapeutic benefit against latent HIV-1 infection, HIV-1 associated neurocognitive disorders, and other HIV-1 comorbidities.
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23
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Link RW, Mele AR, Antell GC, Pirrone V, Zhong W, Kercher K, Passic S, Szep Z, Malone K, Jacobson JM, Dampier W, Wigdahl B, Nonnemacher MR. Investigating the distribution of HIV-1 Tat lengths present in the Drexel Medicine CARES cohort. Virus Res 2019; 272:197727. [PMID: 31437485 DOI: 10.1016/j.virusres.2019.197727] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 07/22/2019] [Accepted: 08/18/2019] [Indexed: 10/26/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) encodes for Tat, a multi-functional regulatory protein involved in transcriptional enhancement and in causing neurotoxicity/central nervous system (CNS) dysfunction. This study examines Sanger sequencing of HIV-1 subtype B Tat from 2006 to 2014 within the Drexel University College of Medicine CNS AIDS Research and Eradication Study (CARES) Cohort to investigate Tat length in patients. The Los Alamos National Laboratory (LANL) database was used as a comparator. Miscoded stop codons were present in the CARES Cohort and LANL and protein variability was highly similar. Tat proteins in CARES and LANL were predominantly 101 residues. There was no observed correlation between Tat length and clinical parameters within the CARES Cohort. Unique Tat lengths found in the CARES Cohort and not in LANL were 31, 36, and 39 residues. When CARES patients were longitudinally examined, sequence lengths of 101 had a low probability of reducing to below 48, and sequences had a high probability of increasing to above 86 residues during their next visit, when below 48 residues in length. This suggests that Tat length is conserved to retain the majority of the proteins function highlighting its importance in viral replication.
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Affiliation(s)
- Robert W Link
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Anthony R Mele
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Gregory C Antell
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Vanessa Pirrone
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Wen Zhong
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Katherine Kercher
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Shendra Passic
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Zsofia Szep
- Center for Clinical and Translational Medicine, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA; Division of Infectious Diseases and HIV Medicine, Department of Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Kim Malone
- Center for Clinical and Translational Medicine, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA; Division of Infectious Diseases and HIV Medicine, Department of Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Jeffrey M Jacobson
- Department of Neuroscience and Comprehensive NeuroAIDS Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA; Center for Translational AIDS Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA; Department of Medicine, Section of Infectious Disease, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Will Dampier
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Clinical and Translational Medicine, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA; Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA; Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA.
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24
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Shrivastava AN, Triller A, Melki R. Cell biology and dynamics of Neuronal Na +/K +-ATPase in health and diseases. Neuropharmacology 2018; 169:107461. [PMID: 30550795 DOI: 10.1016/j.neuropharm.2018.12.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/17/2018] [Accepted: 12/08/2018] [Indexed: 10/27/2022]
Abstract
Neuronal Na+/K+-ATPase is responsible for the maintenance of ionic gradient across plasma membrane. In doing so, in a healthy brain, Na+/K+-ATPase activity accounts for nearly half of total brain energy consumption. The α3-subunit containing Na+/K+-ATPase expression is restricted to neurons. Heterozygous mutations within α3-subunit leads to Rapid-onset Dystonia Parkinsonism, Alternating Hemiplegia of Childhood and other neurological and neuropsychiatric disorders. Additionally, proteins such as α-synuclein, amyloid-β, tau and SOD1 whose aggregation is associated to neurodegenerative diseases directly bind and impair α3-Na+/K+-ATPase activity. The review will provide a summary of neuronal α3-Na+/K+-ATPase functional properties, expression pattern, protein-protein interactions at the plasma membrane, biophysical properties (distribution and lateral diffusion). Lastly, the role of α3-Na+/K+-ATPase in neurological and neurodegenerative disorders will be discussed. This article is part of the special issue entitled 'Mobility and trafficking of neuronal membrane proteins'.
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Affiliation(s)
- Amulya Nidhi Shrivastava
- CEA, Institut François Jacob (MIRcen) and CNRS, Laboratory of Neurodegenerative Diseases (U9199), 18 Route du Panorama, 92265, Fontenay-aux-Roses, France.
| | - Antoine Triller
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, INSERM, CNRS, PSL, Research University, 46 Rue d'Ulm, 75005 Paris, France
| | - Ronald Melki
- CEA, Institut François Jacob (MIRcen) and CNRS, Laboratory of Neurodegenerative Diseases (U9199), 18 Route du Panorama, 92265, Fontenay-aux-Roses, France
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25
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Mele AR, Marino J, Chen K, Pirrone V, Janetopoulos C, Wigdahl B, Klase Z, Nonnemacher MR. Defining the molecular mechanisms of HIV-1 Tat secretion: PtdIns(4,5)P 2 at the epicenter. Traffic 2018; 19:10.1111/tra.12578. [PMID: 29708629 PMCID: PMC6207469 DOI: 10.1111/tra.12578] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 12/18/2022]
Abstract
The human immunodeficiency virus type 1 (HIV-1) transactivator of transcription (Tat) protein functions both intracellularly and extracellularly. Intracellularly, the main function is to enhance transcription of the viral promoter. However, this process only requires a small amount of intracellular Tat. The majority of Tat is secreted through an unconventional mechanism by binding to phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2 ), a phospholipid in the inner leaflet of the plasma membrane that is required for secretion. This interaction is mediated by the basic domain of Tat (residues 48-57) and a conserved tryptophan (residue 11). After binding to PtdIns(4,5)P2 , Tat secretion diverges into multiple pathways, which we categorized as oligomerization-mediated pore formation, spontaneous translocation and incorporation into exosomes. Extracellular Tat has been shown to be neurotoxic and toxic to other cells of the central nervous system (CNS) and periphery, able to recruit immune cells to the CNS and cerebrospinal fluid, and alter the gene expression and morphology of uninfected cells. The effects of extracellular Tat have been examined in HIV-1-associated neurocognitive disorders (HAND); however, only a small number of studies have focused on the mechanisms underlying Tat secretion. In this review, the molecular mechanisms of Tat secretion will be examined in a variety of biologically relevant cell types.
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Affiliation(s)
- Anthony R Mele
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Jamie Marino
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Kenneth Chen
- Department of Biology, University of the Sciences, Philadelphia, Pennsylvania
| | - Vanessa Pirrone
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Chris Janetopoulos
- Department of Biology, University of the Sciences, Philadelphia, Pennsylvania
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Zachary Klase
- Department of Biology, University of the Sciences, Philadelphia, Pennsylvania
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
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Schatz M, Tong PBV, Beaumelle B. Unconventional secretion of viral proteins. Semin Cell Dev Biol 2018; 83:8-11. [PMID: 29571970 DOI: 10.1016/j.semcdb.2018.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/14/2018] [Accepted: 03/14/2018] [Indexed: 12/25/2022]
Abstract
Although largely less numerous and characterized than bacterial secreted effectors, several viral virulence factors are secreted by virus infected cells. However, their mode of secretion only starts to be studied at the molecular level. Several of these viral effectors are secreted using an unconventional secretion pathway, i.e. despite the lack of signal sequence. We here review recent results illustrating the diversity of these pathways. In the case of HIV-1 proteins Tat and matrix (p17) proteins, secretion directly takes place at the plasma membrane level following binding to PI(4,5)P2. The secretion of HTLV-I Tax was found to partly rely on exocytic pathway intermediates. The secretion pathways of VP22 of Herpes simplex virus type I and VP40 of the Ebola virus are less well characterized but VP40 can be recruited to the plasma membrane by PI(4,5)P2 that thus appears as a key partner enabling the unconventional secretion of many viral proteins. Several studies indicated that circulating retroviral transactivating proteins Tat and Tax are involved in the development of AIDS and HTLV-I associated myelopathy/tropical spastic paraparesis, respectively.
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Affiliation(s)
- Malvina Schatz
- IRIM, UMR9004 University of Montpellier-CNRS, 1919 Route de Mende, 34293, MONTPELLIER Cedex 05, France
| | - Phuoc Bao Viet Tong
- IRIM, UMR9004 University of Montpellier-CNRS, 1919 Route de Mende, 34293, MONTPELLIER Cedex 05, France
| | - Bruno Beaumelle
- IRIM, UMR9004 University of Montpellier-CNRS, 1919 Route de Mende, 34293, MONTPELLIER Cedex 05, France.
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Khan N, Datta G, Geiger JD, Chen X. Apolipoprotein E isoform dependently affects Tat-mediated HIV-1 LTR transactivation. J Neuroinflammation 2018; 15:91. [PMID: 29558961 PMCID: PMC5861635 DOI: 10.1186/s12974-018-1129-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 03/13/2018] [Indexed: 12/02/2022] Open
Abstract
Background Apolipoprotein E (ApoE) is the major carrier protein that mediates the transport and delivery of cholesterol and other lipids in the brain. Three isoforms of ApoE (ApoE2, ApoE3, ApoE4) exist in humans, and their relative expression levels impact HIV-1 infection, HIV-1/AIDS disease progression, and cognitive decline associated with HIV-1-associated neurocognitive disorder. Because HIV-1 Tat, a viral protein essential for HIV-1 replication, can bind to low-density lipoprotein receptor-related protein 1 (LRP1) that controls ApoE uptake in the brain, we determined the extent to which different isoforms of ApoE affected Tat-mediated HIV-1 LTR transactivation. Methods Using U87MG glioblastoma cells expressing LTR-driven luciferase, we determined the extent to which LRP1 as well as ApoE2, ApoE3, and ApoE4 affected Tat-mediated HIV-1 LTR transactivation. Results A specific LRP1 antagonist and siRNA knockdown of LRP1 both restricted significantly Tat-mediated LTR transactivation. Of the three ApoEs, ApoE4 was the least potent and effective at preventing HIV-1 Tat internalization and at decreasing Tat-mediated HIV-1 LTR transactivation. Further, Tat-mediated LTR transactivation was attenuated by an ApoE mimetic peptide, and ApoE4-induced restriction of Tat-mediated LTR transactivation was potentiated by an ApoE4 structure modulator that changes ApoE4 into an ApoE3-like phenotype. Conclusions These findings help explain observed differential effects of ApoEs on HIV-1 infectivity and the prevalence of HAND in people living with HIV-1 infection and suggest that ApoE mimetic peptides and ApoE4 structure modulator might be used as a therapeutic strategy against HIV-1 infection and associated neurocognitive disorders. Electronic supplementary material The online version of this article (10.1186/s12974-018-1129-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nabab Khan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Gaurav Datta
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Xuesong Chen
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA.
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Steringer JP, Nickel W. A direct gateway into the extracellular space: Unconventional secretion of FGF2 through self-sustained plasma membrane pores. Semin Cell Dev Biol 2018; 83:3-7. [PMID: 29458182 DOI: 10.1016/j.semcdb.2018.02.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/01/2018] [Accepted: 02/08/2018] [Indexed: 10/17/2022]
Abstract
As illustrated by a diverse set of examples in this special issue, multiple mechanisms of protein secretion have been identified in eukaryotes that do not involve the endoplasmic reticulum (ER) and the Golgi apparatus. Here we focus on the type I pathway with Fibroblast Growth Factor 2 (FGF2) being the most prominent example. Unconventional secretion of FGF2 from cells is mediated by direct protein translocation across the plasma membrane. A unique feature of this process is the ability of FGF2 to form its own membrane translocation intermediate through oligomerization and membrane insertion. This process depends on the phosphoinositide PI(4,5)P2 at the inner leaflet and results in the formation of lipidic membrane pores in the plasma membrane. Various lines of evidence suggest that these pores are characterized by a toroidal architecture with FGF2 oligomers being accommodated in the center of these structures. At the outer leaflet of the plasma membrane, membrane proximal heparan sulfate proteoglycans are required for the final step of FGF2 translocation into the extracellular space. Based upon mutually exclusive interactions of FGF2 with PI(4,5)P2 versus heparan sulfates, an assembly/disassembly pathway has been proposed to be the underlying principle of directional transport of FGF2 across the plasma membrane. Thus, the core mechanism of unconventional secretion of FGF2 is based upon three discrete steps with (i) PI(4,5)P2 dependent oligomerization of FGF2 at the inner leaflet, (ii) insertion of membrane spanning FGF2 oligomers into the plasma membrane and (iii) disassembly at the outer leaflet mediated by heparan sulfates that subsequently retain FGF2 on cell surfaces. This process has recently been reconstituted with an inside-out membrane model system using giant unilamellar vesicles providing a compelling explanation of how FGF2 reaches the extracellular space in an ER/Golgi independent manner. This review is part of a Special Issue of SCDB on "unconventional protein secretion" edited by Walter Nickel and Catherine Rabouille.
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Affiliation(s)
- Julia P Steringer
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
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