1
|
Nickoloff-Bybel EA, Festa L, Meucci O, Gaskill PJ. Co-receptor signaling in the pathogenesis of neuroHIV. Retrovirology 2021; 18:24. [PMID: 34429135 PMCID: PMC8385912 DOI: 10.1186/s12977-021-00569-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022] Open
Abstract
The HIV co-receptors, CCR5 and CXCR4, are necessary for HIV entry into target cells, interacting with the HIV envelope protein, gp120, to initiate several signaling cascades thought to be important to the entry process. Co-receptor signaling may also promote the development of neuroHIV by contributing to both persistent neuroinflammation and indirect neurotoxicity. But despite the critical importance of CXCR4 and CCR5 signaling to HIV pathogenesis, there is only one therapeutic (the CCR5 inhibitor Maraviroc) that targets these receptors. Moreover, our understanding of co-receptor signaling in the specific context of neuroHIV is relatively poor. Research into co-receptor signaling has largely stalled in the past decade, possibly owing to the complexity of the signaling cascades and functions mediated by these receptors. Examining the many signaling pathways triggered by co-receptor activation has been challenging due to the lack of specific molecular tools targeting many of the proteins involved in these pathways and the wide array of model systems used across these experiments. Studies examining the impact of co-receptor signaling on HIV neuropathogenesis often show activation of multiple overlapping pathways by similar stimuli, leading to contradictory data on the effects of co-receptor activation. To address this, we will broadly review HIV infection and neuropathogenesis, examine different co-receptor mediated signaling pathways and functions, then discuss the HIV mediated signaling and the differences between activation induced by HIV and cognate ligands. We will assess the specific effects of co-receptor activation on neuropathogenesis, focusing on neuroinflammation. We will also explore how the use of substances of abuse, which are highly prevalent in people living with HIV, can exacerbate the neuropathogenic effects of co-receptor signaling. Finally, we will discuss the current state of therapeutics targeting co-receptors, highlighting challenges the field has faced and areas in which research into co-receptor signaling would yield the most therapeutic benefit in the context of HIV infection. This discussion will provide a comprehensive overview of what is known and what remains to be explored in regard to co-receptor signaling and HIV infection, and will emphasize the potential value of HIV co-receptors as a target for future therapeutic development. ![]()
Collapse
Affiliation(s)
- E A Nickoloff-Bybel
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - L Festa
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, 240 S. 40th Street, Philadelphia, PA, 19104, USA
| | - O Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.,Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, 19102, USA
| | - P J Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.
| |
Collapse
|
2
|
Chen L, Keppler OT, Schölz C. Post-translational Modification-Based Regulation of HIV Replication. Front Microbiol 2018; 9:2131. [PMID: 30254620 PMCID: PMC6141784 DOI: 10.3389/fmicb.2018.02131] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/20/2018] [Indexed: 12/13/2022] Open
Abstract
Human immunodeficiency virus (HIV) relies heavily on the host cellular machinery for production of viral progeny. To exploit cellular proteins for replication and to overcome host factors with antiviral activity, HIV has evolved a set of regulatory and accessory proteins to shape an optimized environment for its replication and to facilitate evasion from the immune system. Several cellular pathways are hijacked by the virus to modulate critical steps during the viral life cycle. Thereby, post-translational modifications (PTMs) of viral and cellular proteins gain increasingly attention as modifying enzymes regulate virtually every step of the viral replication cycle. This review summarizes the current knowledge of HIV-host interactions influenced by PTMs with a special focus on acetylation, ubiquitination, and phosphorylation of proteins linked to cellular signaling and viral replication. Insights into these interactions are surmised to aid development of new intervention strategies.
Collapse
Affiliation(s)
- Lin Chen
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Oliver T Keppler
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Christian Schölz
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| |
Collapse
|
3
|
Biophysical characteristics of hematopoietic cells during division. Exp Cell Res 2018; 367:132-136. [DOI: 10.1016/j.yexcr.2018.03.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 03/20/2018] [Accepted: 03/21/2018] [Indexed: 01/11/2023]
|
4
|
HIV-1 Vpu Downmodulates ICAM-1 Expression, Resulting in Decreased Killing of Infected CD4 + T Cells by NK Cells. J Virol 2017; 91:JVI.02442-16. [PMID: 28148794 DOI: 10.1128/jvi.02442-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/26/2017] [Indexed: 12/20/2022] Open
Abstract
HIV-1 Vpu is known to alter the expression of numerous cell surface molecules. Given the ever-increasing list of Vpu targets identified to date, we undertook a proteomic screen to discover novel cell membrane proteins modulated by this viral protein. Plasma membrane proteome isolates from Vpu-inducible T cells were subjected to stable isotope labeling of amino acids in cell culture (SILAC)-based mass spectrometry analysis, and putative targets were validated by infection of primary CD4+ T cells. We report here that while intercellular adhesion molecule 1 (ICAM-1) and ICAM-3 are upregulated by HIV-1 infection, expression of Vpu offsets this increase by downregulating these molecules from the cell surface. Specifically, we show that Vpu is sufficient to downregulate and deplete ICAM-1 in a manner requiring the Vpu transmembrane domain and a dual-serine (S52/S56) motif necessary for recruitment of the beta-transducin repeat-containing E3 ubiquitin protein ligase (β-TrCP) component of the Skp, Cullin, F-box (SCFβ-TrCP) E3 ubiquitin ligase. Vpu interacts with ICAM-1 to induce its proteasomal degradation. Interestingly, the E3 ubiquitin ligase component β-TrCP-1 is dispensable for ICAM-1 surface downregulation yet is necessary for ICAM-1 degradation. Functionally, Vpu-mediated ICAM-1 downregulation lowers packaging of this adhesion molecule into virions, resulting in decreased infectivity. Importantly, while Vpu-mediated downregulation of ICAM-3 has a limited effect on the conjugation of NK cells to HIV-1-infected CD4+ T cells, downregulation of ICAM-1 by Vpu results in a reduced ability of NK cells to bind and kill infected T cells. Vpu-mediated ICAM-1 downregulation may therefore represent an evolutionary compromise in viral fitness by impeding the formation of cell-to-cell contacts between immune cells and infected T cells at the cost of decreased virion infectivity.IMPORTANCE The major barrier to eradicating HIV-1 infection is the establishment of treatment-resistant reservoirs early in infection. Vpu-mediated ICAM-1 downregulation may contribute to the evasion of cell-mediated immunity during acute infection to promote viral dissemination and the development of viral reservoirs. By aiding the immune system to clear infection prior to the development of reservoirs, novel treatments designed to disrupt Vpu-mediated ICAM-1 downregulation may be beneficial during acute infection or as a prophylactic treatment.
Collapse
|
5
|
Bui VC, Nguyen TH. The role of CD4 on mechanical properties of live cell membrane. J Biomed Mater Res A 2015; 104:239-44. [DOI: 10.1002/jbm.a.35559] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/13/2015] [Accepted: 09/03/2015] [Indexed: 01/21/2023]
Affiliation(s)
- Van-Chien Bui
- Center for Innovation Competence - Humoral Immune Reactions in Cardiovascular Diseases (ZIK HIKE); University of Greifswald; 17489 Greifswald Germany
| | - Thi-Huong Nguyen
- Center for Innovation Competence - Humoral Immune Reactions in Cardiovascular Diseases (ZIK HIKE); University of Greifswald; 17489 Greifswald Germany
| |
Collapse
|
6
|
Sufiawati I, Tugizov SM. HIV-associated disruption of tight and adherens junctions of oral epithelial cells facilitates HSV-1 infection and spread. PLoS One 2014; 9:e88803. [PMID: 24586397 PMCID: PMC3931628 DOI: 10.1371/journal.pone.0088803] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 01/15/2014] [Indexed: 11/18/2022] Open
Abstract
Herpes simplex virus (HSV) types 1 and 2 are the most common opportunistic infections in HIV/AIDS. In these immunocompromised individuals, HSV-1 reactivates and replicates in oral epithelium, leading to oral disorders such as ulcers, gingivitis, and necrotic lesions. Although the increased risk of HSV infection may be mediated in part by HIV-induced immune dysfunction, direct or indirect interactions of HIV and HSV at the molecular level may also play a role. In this report we show that prolonged interaction of the HIV proteins tat and gp120 and cell-free HIV virions with polarized oral epithelial cells leads to disruption of tight and adherens junctions of epithelial cells through the mitogen-activated protein kinase signaling pathway. HIV-induced disruption of oral epithelial junctions facilitates HSV-1 paracellular spread between the epithelial cells. Furthermore, HIV-associated disruption of adherens junctions exposes sequestered nectin-1, an adhesion protein and critical receptor for HSV envelope glycoprotein D (gD). Exposure of nectin-1 facilitates binding of HSV-1 gD, which substantially increases HSV-1 infection of epithelial cells with disrupted junctions over that of cells with intact junctions. Exposed nectin-1 from disrupted adherens junctions also increases the cell-to-cell spread of HSV-1 from infected to uninfected oral epithelial cells. Antibodies to nectin-1 and HSV-1 gD substantially reduce HSV-1 infection and cell-to-cell spread, indicating that HIV-promoted HSV infection and spread are mediated by the interaction of HSV gD with HIV-exposed nectin-1. Our data suggest that HIV-associated disruption of oral epithelial junctions may potentiate HSV-1 infection and its paracellular and cell-to-cell spread within the oral mucosal epithelium. This could be one of the possible mechanisms of rapid development of HSV-associated oral lesions in HIV-infected individuals.
Collapse
Affiliation(s)
- Irna Sufiawati
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Sharof M. Tugizov
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
- Department of Orofacial Sciences, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
| |
Collapse
|
7
|
Abbas W, Herbein G. Plasma membrane signaling in HIV-1 infection. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:1132-42. [PMID: 23806647 DOI: 10.1016/j.bbamem.2013.06.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/12/2013] [Accepted: 06/16/2013] [Indexed: 10/26/2022]
Abstract
Plasma membrane is a multifunctional structure that acts as the initial barrier against infection by intracellular pathogens. The productive HIV-1 infection depends upon the initial interaction of virus and host plasma membrane. Immune cells such as CD4+ T cells and macrophages contain essential cell surface receptors and molecules such as CD4, CXCR4, CCR5 and lipid raft components that facilitate HIV-1 entry. From plasma membrane HIV-1 activates signaling pathways that prepare the grounds for viral replication. Through viral proteins HIV-1 hijacks host plasma membrane receptors such as Fas, TNFRs and DR4/DR5, which results in immune evasion and apoptosis both in infected and uninfected bystander cells. These events are hallmark in HIV-1 pathogenesis that leads towards AIDS. The interplay between HIV-1 and plasma membrane signaling has much to offer in terms of viral fitness and pathogenicity, and a better understanding of this interplay may lead to development of new therapeutic approaches. This article is part of a Special Issue entitled: Viral Membrane Proteins - Channels for Cellular Networking.
Collapse
Affiliation(s)
- Wasim Abbas
- Department of Virology, EA 4266 "Pathogens & Inflammation", SFR FED4234, University of Franche-Comte, CHRU Besançon, F-25030 Besançon, France.
| | - Georges Herbein
- Department of Virology, EA 4266 "Pathogens & Inflammation", SFR FED4234, University of Franche-Comte, CHRU Besançon, F-25030 Besançon, France.
| |
Collapse
|
8
|
Rozmus J, Schultz KR, Wynne K, Kariminia A, Satyanarayana P, Krailo M, Grupp SA, Gilman AL, Goldman FD. Early and late extensive chronic graft-versus-host disease in children is characterized by different Th1/Th2 cytokine profiles: findings of the Children's Oncology Group Study ASCT0031. Biol Blood Marrow Transplant 2011; 17:1804-13. [PMID: 21669298 PMCID: PMC3190042 DOI: 10.1016/j.bbmt.2011.05.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 05/18/2011] [Indexed: 12/15/2022]
Abstract
Numerous mechanisms underlie chronic graft-versus-host disease (cGVHD), including skewing of Th1/Th2 cytokine expression. There are biological differences between early-onset and late-onset cGVHD. To test whether different Th1/Th2 cytokines are associated with early- or late-onset cGVHD, peripheral blood was collected from 63 children enrolled on the Children's Oncology Group Phase III trial ASCT0031 evaluating hydroxychloroquine therapy for newly diagnosed extensive cGVHD. mRNA expression of interferon (IFN)-γ and interleukin (IL)-2, -4, and -10 from stimulated peripheral blood mononuclear cells was evaluated by quantitative polymerase chain reaction. Early-onset cGVHD (n = 33) was characterized by decreased expression of IFN-γ and IL-2 mRNA after nonspecific phorbol 12-myristate 13-acetate-ionomycin stimulation. In contrast, late-onset cGVHD (n = 11) was characterized by decreased expression of IL-4 and IL-2 mRNA after anti-CD3 stimulation of T cells. Receiver-operating characteristic curve analysis revealed that IFN-γ expression was correlated with the absence of early cGVHD (area under the curve [AUC] = 0.77) and that IL-4 (AUC = 0.89) and IL-2 (AUC = 0.84) expression was correlated with the absence of late cGVHD. There was no correlation between cytokine expression and a specific immune cell subset. Increased expression of Foxp3 mRNA was seen in early-onset cGVHD and late controls. The different time-dependent cytokine profiles in patients with newly diagnosed cGVHD suggests that the mechanisms underlying cGVHD are temporally regulated. Although larger validation studies are needed, our data suggest that cytokine profiles have a potential use as biomarkers for the diagnosis of cGVHD.
Collapse
Affiliation(s)
- Jacob Rozmus
- Children’s Oncology Group, Pediatric Hematology/Oncology/BMT, BC Children’s Hospital/University of British Columbia, Vancouver, BC
| | - Kirk R. Schultz
- Children’s Oncology Group, Pediatric Hematology/Oncology/BMT, BC Children’s Hospital/University of British Columbia, Vancouver, BC
- Children’s Oncology Group, Dept. Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC
| | - Kristin Wynne
- Children’s Oncology Group, Pediatric Hematology/Oncology/BMT, BC Children’s Hospital/University of British Columbia, Vancouver, BC
| | - Amina Kariminia
- Children’s Oncology Group, Pediatric Hematology/Oncology/BMT, BC Children’s Hospital/University of British Columbia, Vancouver, BC
| | - Preeti Satyanarayana
- Children’s Oncology Group, Department of Family Medicine, Sacred Heart HealthCare System, Allentown, PA
| | - Mark Krailo
- Children’s Oncology Group, Department of Preventative Medicine, University of Southern California, Los Angeles, CA
| | - Stephan A. Grupp
- Children’s Oncology Group, The Children’s Hospital of Philadelphia/University of Pennsylvania School of Medicine, PA
| | - Andrew L. Gilman
- Children’s Oncology Group, Levine Children’s Hospital, Charlotte, NC
| | - Frederick D. Goldman
- Children’s Oncology Group, Department of Pediatrics, Division of Hematology Oncology, Children’s Hospital of Alabama, Birmingham, AL
| |
Collapse
|
9
|
Pashankar F, Singhal V, Akabogu I, Gatti RA, Goldman FD. Intact T cell responses in ataxia telangiectasia. Clin Immunol 2006; 120:156-62. [PMID: 16762595 DOI: 10.1016/j.clim.2006.04.568] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 04/07/2006] [Accepted: 04/13/2006] [Indexed: 10/24/2022]
Abstract
Ataxia telangiectasia (A-T) is an autosomal recessive multisystem disorder associated with a variable immune deficiency. The mechanism for this remains unclear. Qualitative and quantitative defects of cellular immunity have been previously reported. However, despite laboratory evidence of significant immune abnormalities, opportunistic infections are uncommon. To address this discrepancy, we analyzed cytokine production by quantitative real-time PCR and T cell function at the single cell level by flow cytometry in four A-T patients. CD4 and CD8 T cell subsets from these patients displayed intact signaling in response to anti-CD3 stimulation, similar to controls. Stimulated T cells from A-T patients also produced normal to increased levels of Th1 (IL-2, IFN-gamma) and Th2 (IL-10, IL-4) cytokines, relative to control values. Our results suggest that T cells from A-T patients may be more functionally intact than previously observed. This helps to explain the paucity of opportunistic infections encountered, unlike that encountered in other primary immunodeficiencies.
Collapse
Affiliation(s)
- Farzana Pashankar
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA
| | | | | | | | | |
Collapse
|
10
|
Affiliation(s)
- Akira Ono
- Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, National Institutes of Health, Maryland 21702, USA
| | | |
Collapse
|
11
|
Badr G, Borhis G, Treton D, Moog C, Garraud O, Richard Y. HIV Type 1 Glycoprotein 120 Inhibits Human B Cell Chemotaxis to CXC Chemokine Ligand (CXCL) 12, CC Chemokine Ligand (CCL)20, and CCL21. THE JOURNAL OF IMMUNOLOGY 2005; 175:302-10. [PMID: 15972662 DOI: 10.4049/jimmunol.175.1.302] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We analyzed the modulation of human B cell chemotaxis by the gp120 proteins of various HIV-1 strains. X4 and X4/R5 gp120 inhibited B cell chemotaxis toward CXCL12, CCL20, and CCL21 by 40-50%, whereas R5 gp120 decreased inhibition by 20%. This gp120-induced inhibition was strictly dependent on CXCR4 or CCR5 and lipid rafts but not on CD4 or V(H)3-expressing BCR. Inhibition did not impair the expression or ligand-induced internalization of CCR6 and CCR7. Our data suggest that gp120/CXCR4 and gp120/CCR5 interactions lead to the cross-desensitization of CCR6 and CCR7 because gp120 does not bind CCR6 and CCR7. Unlike CXCL12, gp120 did not induce the activation of phospholipase Cbeta3 and PI3K downstream from CXCR4, whereas p38 MAPK activation was observed. Similar results were obtained if gp120-treated cells were triggered by CCL21 and CCL20. Our results are consistent with a blockade restricted to signaling pathways using phosphatidylinositol-4,5-bisphosphate as a substrate. X4 and X4/R5 gp120 induced the cleavage of CD62 ligand by a mechanism dependent on matrix metalloproteinase 1 and 3, CD4, CXCR4, Galpha(i), and p38 MAPK, whereas R5 gp120 did not. X4 and X4/R5 gp120 also induced the relocalization of cytoplasmic CD95 to the membrane and a 23% increase in CD95-mediated apoptosis. No such effects were observed with R5 gp120. The gp120-induced decrease in B cell chemotaxis and CD62 ligand expression, and increase in CD95-mediated B cell apoptosis probably have major deleterious effects on B cell responsiveness during HIV infection and in vaccination trials.
Collapse
Affiliation(s)
- Gamal Badr
- Institut National de la Santé et de la Recherche Medicale, Unité 131, Institut Paris-Sud sur les Cytokines, Clamart, France
| | | | | | | | | | | |
Collapse
|
12
|
Reuter S, Kaumanns P, Buschhorn SB, Dittmar MT. Role of HIV-2 envelope in Lv2-mediated restriction. Virology 2005; 332:347-58. [PMID: 15661166 DOI: 10.1016/j.virol.2004.11.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Revised: 09/24/2004] [Accepted: 11/18/2004] [Indexed: 11/22/2022]
Abstract
We have characterized envelope protein pseudotyped HIV-2 particles derived from two HIV-2 isolates termed prCBL23 and CBL23 in order to define the role of the envelope protein for the Lv2-mediated restriction to infection. Previously, it has been described that the primary isolate prCBL23 is restricted to infection of several human cell types, whereas the T cell line adapted isolate CBL23 is not restricted in these cell types. Molecular cloning of the two isolates revealed that the env and the gag gene are responsible for the observed phenotype and that this restriction is mediated by Lv2, which is distinct from Ref1/Lv1 (Schmitz, C., Marchant, D., Neil, S.J., Aubin, K., Reuter, S., Dittmar, M.T., McKnight, A., Kizhatil, K., Albritton, L.M., 2004. Lv2, a novel postentry restriction, is mediated by both capsid and envelope. J. Virol. 78 (4), 2006-2016). We generated pseudotyped viruses consisting of HIV-2 (ROD-ADeltaenv-GFP, ROD-ADeltaenv-RFP, or ROD-ADeltaenv-REN) and the prCBL23 or CBL23 envelope proteins as well as chimeric proteins between these envelopes. We demonstrate that a single amino acid exchange at position 74 in the surface unit of CBL23-Env confers restriction to infection. This single point mutation causes tighter CD4 binding, resulting in a less efficient fusion into the cytosol of the restricted cell line. Prevention of endosome formation and prevention of endosome acidification enhance infectivity of the restricted particles for GHOST/X4 cells indicating a degradative lysosomal pathway as a cause for the reduced cytosolic entry. The described restriction to infection of the primary isolate prCBL23 is therefore largely caused by an entry defect. A remaining restriction to infection (19-fold) is preserved when endosomal acidification is prevented. This restriction to infection is also dependent on the presence of the point mutation at position 74 (G74E).
Collapse
Affiliation(s)
- Sandra Reuter
- Department of Virology, University of Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany
| | | | | | | |
Collapse
|
13
|
Balabanian K, Harriague J, Décrion C, Lagane B, Shorte S, Baleux F, Virelizier JL, Arenzana-Seisdedos F, Chakrabarti LA. CXCR4-tropic HIV-1 envelope glycoprotein functions as a viral chemokine in unstimulated primary CD4+ T lymphocytes. THE JOURNAL OF IMMUNOLOGY 2005; 173:7150-60. [PMID: 15585836 DOI: 10.4049/jimmunol.173.12.7150] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Interaction of HIV-1 envelope glycoprotein gp120 with the chemokine receptor CXCR4 triggers not only viral entry but also an array of signal transduction cascades. Whether gp120 induces an incomplete or aberrant set of signals, or whether it can function as a full CXCR4 agonist, remains unclear. We report that, in unstimulated human primary CD4(+) T cells, the spectrum of signaling responses induced by gp120 through CXCR4 paralleled that induced by the natural ligand stromal cell-derived factor 1/CXCL12. gp120 activated heterotrimeric G proteins and the major G protein-dependent pathways, including calcium mobilization, phosphoinositide-3 kinase, and Erk-1/2 MAPK activation. Interestingly, gp120 caused rapid actin cytoskeleton rearrangements and profuse membrane ruffling, as evidenced by dynamic confocal imaging. This coordinated set of events resulted in a bona fide chemotactic response. Inactivated HIV-1 virions that harbored conformationally intact envelope glycoproteins also caused actin polymerization and chemotaxis, while similar virions devoid of envelope glycoproteins did not. Thus gp120, in monomeric as well as oligomeric, virion-associated form, elicited a complex cellular response that mimicked the effects of a chemokine. HIV-1 has therefore the capacity to dysregulate the vast CD4(+) T cell population that expresses CXCR4. In addition, HIV-1 may exploit its chemotactic properties to retain potential target cells and locally perturb their cytoskeleton, thereby facilitating viral transmission.
Collapse
|
14
|
Wielgosz MM, Rauch DA, Jones KS, Ruscetti FW, Ratner L. Cholesterol dependence of HTLV-I infection. AIDS Res Hum Retroviruses 2005; 21:43-50. [PMID: 15665643 PMCID: PMC2671014 DOI: 10.1089/aid.2005.21.43] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cholesterol-rich plasma membrane microdomains are important for entry of many viruses, including retroviruses. Depletion of cholesterol with 2-hydroxypropyl-beta-cyclodextrin inhibits entry of human T cell leukemia virus type I (HTLV-1) and HTLV-I envelope pseudotyped lentivirus particles. Using a soluble fusion protein of the HTLV-I surface envelope protein with the immunoglobulin Fc domain, the HTLV-I receptor was found to colocalize with a raft-associated marker and to cluster in specific plasma membrane microdomains. Depletion of cholesterol did not alter receptor binding activity, suggesting a requirement for cholesterol in a postbinding virus entry step.
Collapse
Affiliation(s)
- Matthew M Wielgosz
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | | | | | | |
Collapse
|
15
|
Knudson M, Kulkarni S, Ballas ZK, Bessler M, Goldman F. Association of immune abnormalities with telomere shortening in autosomal-dominant dyskeratosis congenita. Blood 2004; 105:682-8. [PMID: 15238429 DOI: 10.1182/blood-2004-04-1673] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dyskeratosis congenita (DC) is an inherited bone marrow failure disorder characterized by abnormal skin pigmentation and nail dystrophy. We have recently described, in 10 members of a large 3-generation family, an autosomal-dominant form of DC (AD DC) that is due to a mutation in the gene-encoding human telomerase RNA (TERC), resulting in telomere shortening. In studying the immunologic consequences of TERC mutations, severe B lymphopenia and decreased immunoglobulin M (IgM) levels were noted. T cells were found to overexpress senescent markers, including CD57 and Fas receptor, and were moderately reduced in cell number. To determine whether these in vivo findings were related to cellular replicative defects, short-term cultures of AD DC lymphocytes were established to measure proliferation, mitoses, and apoptosis. AD DC lymphocytes displayed a markedly reduced proliferative capacity and increased basal apoptotic rate. Finally, telomere shortening was most prominent in third-generation subjects, and there appeared to be a correlation between telomere length and in vivo and in vitro immune findings. In summary, the observed lymphopenia and hypogammaglobulinemia in AD DC is likely a consequence of replicative failure and premature senescence of lymphocytes, supporting a role of telomerase activity in immune homeostasis.
Collapse
Affiliation(s)
- Matt Knudson
- Department of Pediatrics, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA
| | | | | | | | | |
Collapse
|
16
|
Nisole S, Saïb A. Early steps of retrovirus replicative cycle. Retrovirology 2004; 1:9. [PMID: 15169567 PMCID: PMC421752 DOI: 10.1186/1742-4690-1-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2004] [Accepted: 05/14/2004] [Indexed: 12/28/2022] Open
Abstract
During the last two decades, the profusion of HIV research due to the urge to identify new therapeutic targets has led to a wealth of information on the retroviral replication cycle. However, while the late stages of the retrovirus life cycle, consisting of virus replication and egress, have been partly unraveled, the early steps remain largely enigmatic. These early steps consist of a long and perilous journey from the cell surface to the nucleus where the proviral DNA integrates into the host genome. Retroviral particles must bind specifically to their target cells, cross the plasma membrane, reverse-transcribe their RNA genome, while uncoating the cores, find their way to the nuclear membrane and penetrate into the nucleus to finally dock and integrate into the cellular genome. Along this journey, retroviruses hijack the cellular machinery, while at the same time counteracting cellular defenses. Elucidating these mechanisms and identifying which cellular factors are exploited by the retroviruses and which hinder their life cycle, will certainly lead to the discovery of new ways to inhibit viral replication and to improve retroviral vectors for gene transfer. Finally, as proven by many examples in the past, progresses in retrovirology will undoubtedly also provide some priceless insights into cell biology.
Collapse
Affiliation(s)
- Sébastien Nisole
- Division of Virology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
| | - Ali Saïb
- CNRS UPR9051, Hôpital Saint-Louis, 1 Avenue Claude Vellefaux, 75475 Paris cedex 10, France
| |
Collapse
|
17
|
Kim FJ, Battini JL, Manel N, Sitbon M. Emergence of vertebrate retroviruses and envelope capture. Virology 2004; 318:183-91. [PMID: 14972546 DOI: 10.1016/j.virol.2003.09.026] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Revised: 09/10/2003] [Accepted: 09/14/2003] [Indexed: 11/28/2022]
Abstract
Retroviruses are members of the superfamily of retroelements, mobile genetic elements that transpose via an RNA intermediate. However, retroviruses are distinct from other retroelements in that their "transposition" is not confined to single cells but extends to neighboring cells and organisms. As such, the "transposition" of these elements is defined as infection. It appears that a key step in the conversion of a retrotransposon into a retrovirus is the modular acquisition or capture of an envelope glycoprotein (Env) which facilitates dissemination from its initial host cell. Here we present several examples of retroviruses for which envelope capture has been identified. Indeed, capture may explain the notable conservation of env sequences among otherwise phylogenetically distant retroviruses. In a recent example, sequence homologies reported between the env of the phylogenetically distant murine leukemia viruses (MLV) and human T cell leukemia viruses (HTLV) argue in favor of an env capture by the latter. Env acquisition can provide new adaptive properties to replication-competent viruses in addition to altering their host range. Also, the captured env can alter the spectrum of physiological affects of infection in new host cells and organisms. The elucidation of such envelope exchanges and properties thereof should contribute significantly to the clarification of retroviral phylogeny, insight into retroviral pathogenesis, and to the discovery of new retroviruses.
Collapse
Affiliation(s)
- Felix J Kim
- Institut de Génétique Moléculaire de Montpellier (IGMM), CNRS-UMR5535, IFR122, F-34293 Montpellier, cedex 5, France
| | | | | | | |
Collapse
|
18
|
Masci AM, Galgani M, Cassano S, De Simone S, Gallo A, De Rosa V, Zappacosta S, Racioppi L. HIV-1 gp120 induces anergy in naive T lymphocytes through CD4-independent protein kinase-A-mediated signaling. J Leukoc Biol 2003; 74:1117-24. [PMID: 12972513 DOI: 10.1189/jlb.0503239] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The ability of the envelope glycoprotein gp120 [human immunodeficiency virus (HIV) env] to induce intracellular signals is thought to contribute to HIV-1 pathogenesis. In the present study, we found that the exposure of CD4+ CD45RA+ naive T cells to HIVenv results in a long-lasting hyporesponsiveness to antigen stimulation. This phenomenon is not dependent on CD4-mediated signals and also can be generated by the exposure of naive T cell to soluble CD4-HIVenv complexes. The analysis of the proximal signaling reveals that HIVenv does not activate Lck as well as the mitogen-activated protein kinase intermediate cascade. Conversely, the envelope glycoprotein stimulates the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) activity and induces the progressive accumulation of the phosphorylated form of the cAMP-responsive element binding. Of note, the ligation of CXCR4 by stromal cell-derived factor-1alpha but not the engagement of CD4 by monoclonal antibody stimulates the PKA activity and induces a long-lasting hyporesponsivity state in naive CD4+ lymphocytes. The pretreatment of lymphocytes with H89, a cell-permeable PKA inhibitor, prevents the induction of anergy. These findings reveal a novel mechanism by which HIVenv may modulate the processes of clonal expansion, homeostatic proliferation, and terminal differentiation of the naive T lymphocyte subset.
Collapse
Affiliation(s)
- Anna Maria Masci
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università di Napoli Federico II, 5 via S. Pansini, I-80131 Naples, Italy
| | | | | | | | | | | | | | | |
Collapse
|