scholarly journals Nef enhances HIV-1 replication and infectivity independently of SERINC3 and SERINC5 in CEM T cells

2020 ◽  
Author(s):  
Peter W. Ramirez ◽  
Aaron A. Angerstein ◽  
Marissa Suarez ◽  
Thomas Vollbrecht ◽  
Jared Wallace ◽  
...  
Keyword(s):  
Growth Rate ◽  
T Cells ◽  
T Cell ◽  
Viral Replication ◽  
Cell Line ◽  
Host Protein ◽  
Target Cells ◽  
Viral Fusion ◽  
Viral Growth ◽  
Hiv 1

AbstractThe lentiviral nef gene encodes several discrete activities aimed at co-opting or antagonizing cellular proteins and pathways to defeat host defenses and maintain persistent infection. Primary functions of Nef include downregulation of CD4 and MHC class-I from the cell surface, disruption or mimicry of T-cell receptor signaling, and enhancement of viral infectivity by counteraction of the host antiretroviral proteins SERINC3 and SERINC5. In the absence of Nef, SERINC3 and SERINC5 incorporate into virions and inhibit viral fusion with target cells, decreasing infectivity. However, whether Nef’s counteraction of SERINC3 and SERINC5 is the cause of its positive influence on viral growth-rate in CD4-positive T cells is unclear. Here, we utilized CRISPR/Cas9 to knockout SERINC3 and SERINC5 in a leukemic CD4-positive T cell line (CEM) that displays robust nef-related infectivity and growth-rate phenotypes. As previously reported, viral replication was severely attenuated in CEM cells infected with HIV-1 lacking Nef (HIV-1ΔNef). This attenuated growth-rate phenotype was observed regardless of whether or not the coding regions of the serinc3 and serinc5 genes were intact. Moreover, knockout of serinc3 and serinc5 failed to restore the infectivity of HIV-1ΔNef virions produced from infected CEM cells in single-cycle replication experiments using CD4-positive HeLa cells as targets. Taken together, our results corroborate a recent study using another T-lymphoid cell line (MOLT-3) and suggest that Nef modulates a still unidentified host protein(s) to enhance viral growth rate and infectivity in CD4-positive T cells.ImportanceHIV-1 Nef is a major pathogenicity factor in vivo. A well-described activity of Nef is the enhancement of virion-infectivity and viral propagation in vitro. The infectivity-effect has been attributed to Nef’s ability to prevent the cellular, antiretroviral proteins SERINC3 and SERINC5 from incorporating into viral particles. While the activity of the SERINCs as inhibitors of retroviral infectivity has been well-documented, the role these proteins play in controlling HIV-1 replication is less clear. We report here that genetic disruption of SERINC3 and SERINC5 rescues neither viral replication-rate nor the infectivity of cell-free virions produced from CD4-positive T cells of the CEM lymphoblastoid line infected with viruses lacking Nef. This indicates that failure to modulate SERINC3 and SERINC5 is not the cause of the virologic attenuation of nef-negative HIV-1 observed using this system.

scholarly journals Consequences of HLA-B*13-Associated Escape Mutations on HIV-1 Replication and Nef Function

2015 ◽  
Vol 89 (22) ◽  
pp. 11557-11571 ◽  
Author(s):  
Aniqa Shahid ◽  
Alex Olvera ◽  
Gursev Anmole ◽  
Xiaomei T. Kuang ◽  
Laura A. Cotton ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Hla Class I ◽  
Replication Capacity ◽  
Target Cells ◽  
Fitness Costs ◽  
Ctl Escape ◽  
The Impact ◽  
Hiv 1

ABSTRACTHLA-B*13 is associated with superiorin vivoHIV-1 viremia control. Protection is thought to be mediated by sustained targeting of key cytotoxic T lymphocyte (CTL) epitopes and viral fitness costs of CTL escape in Gag although additional factors may contribute. We assessed the impact of 10 published B*13-associated polymorphisms in Gag, Pol, and Nef, in 23 biologically relevant combinations, on HIV-1 replication capacity and Nef-mediated reduction of cell surface CD4 and HLA class I expression. Mutations were engineered into HIV-1NL4.3, and replication capacity was measured using a green fluorescent protein (GFP) reporter T cell line. Nef-mediated CD4 and HLA-A*02 downregulation was assessed by flow cytometry, and T cell recognition of infected target cells was measured via coculture with an HIV-specific luciferase reporter cell line. When tested individually, only Gag-I147L and Gag-I437L incurred replicative costs (5% and 17%, respectively), consistent with prior reports. The Gag-I437L-mediated replication defect was rescued to wild-type levels by the adjacent K436R mutation. A novel B*13 epitope, comprising 8 residues and terminating at Gag147, was identified in p24Gag(GQMVHQAIGag140–147). No other single or combination Gag, Pol, or Nef mutant impaired viral replication. Single Nef mutations did not affect CD4 or HLA downregulation; however, the Nef double mutant E24Q-Q107R showed 40% impairment in HLA downregulation with no evidence of Nef stability defects. Moreover, target cells infected with HIV-1-NefE24Q-Q107Rwere recognized better by HIV-specific T cells than those infected with HIV-1NL4.3or single Nef mutants. Our results indicate that CTL escape in Gag and Nef can be functionally costly and suggest that these effects may contribute to long-term HIV-1 control by HLA-B*13.IMPORTANCEProtective effects of HLA-B*13 on HIV-1 disease progression are mediated in part by fitness costs of CTL escape mutations in conserved Gag epitopes, but other mechanisms remain incompletely known. We extend our knowledge of the impact of B*13-driven escape on HIV-1 replication by identifying Gag-K436R as a compensatory mutation for the fitness-costly Gag-I437L. We also identify Gag-I147L, the most rapidly and commonly selected B*13-driven substitution in HIV-1, as a putative C-terminal anchor residue mutation in a novel B*13 epitope. Most notably, we identify a novel escape-driven fitness defect: B*13-driven substitutions E24Q and Q107R in Nef, when present together, substantially impair this protein's ability to downregulate HLA class I. This, in turn, increases the visibility of infected cells to HIV-specific T cells. Our results suggest that B*13-associated escape mutations impair HIV-1 replication by two distinct mechanisms, that is, by reducing Gag fitness and dampening Nef immune evasion function.

scholarly journals Modulation of the CCR5 Receptor/Ligand Axis by Seminal Plasma and the Utility of In Vitro versus In Vivo Models

2019 ◽  
Vol 93 (11) ◽  
Author(s):  
Jennifer A. Juno ◽  
Kathleen M. Wragg ◽  
Anne B. Kristensen ◽  
Wen Shi Lee ◽  
Kevin J. Selva ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Seminal Plasma ◽  
Target Cells ◽  
Ccr5 Expression ◽  
Ccr5 Receptor ◽  
The Impact ◽  
Hiv 1

ABSTRACT Sexual HIV-1 transmission occurs primarily in the presence of semen. Although data from macaque studies suggest that CCR5+ CD4+ T cells are initial targets for HIV-1 infection, the impact of semen on T cell CCR5 expression and ligand production remains inconclusive. To determine if semen modulates the lymphocyte CCR5 receptor/ligand axis, primary human T cell CCR5 expression and natural killer (NK) cell anti-HIV-1 antibody-dependent beta chemokine production was assessed following seminal plasma (SP) exposure. Purified T cells produce sufficient quantities of RANTES to result in a significant decline in CCR5bright T cell frequency following 16 h of SP exposure (P = 0.03). Meanwhile, NK cells retain the capacity to produce limited amounts of MIP-1α/MIP-1β in response to anti-HIV-1 antibody-dependent stimulation (median, 9.5% MIP-1α+ and/or MIP-1β+), despite the immunosuppressive nature of SP. Although these in vitro experiments suggest that SP-induced CCR5 ligand production results in the loss of surface CCR5 expression on CD4+ T cells, the in vivo implications are unclear. We therefore vaginally exposed five pigtail macaques to SP and found that such exposure resulted in an increase in CCR5+ HIV-1 target cells in three of the animals. The in vivo data support a growing body of evidence suggesting that semen exposure recruits target cells to the vagina that are highly susceptible to HIV-1 infection, which has important implications for HIV-1 transmission and vaccine design. IMPORTANCE The majority of HIV-1 vaccine studies do not take into consideration the impact that semen exposure might have on the mucosal immune system. In this study, we demonstrate that seminal plasma (SP) exposure can alter CCR5 expression on T cells. Importantly, in vitro studies of T cells in culture cannot replicate the conditions under which immune cells might be recruited to the genital mucosa in vivo, leading to potentially erroneous conclusions about the impact of semen on mucosal HIV-1 susceptibility.

scholarly journals Lenalidomide Enhances CAR-T Cell Activity Against Solid Tumor Cells

2020 ◽  
Vol 29 ◽  
pp. 096368972092082 ◽  
Author(s):  
Zhixiong Wang ◽  
Guomin Zhou ◽  
Na Risu ◽  
Jiayu Fu ◽  
Yan Zou ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Cytokine Secretion ◽  
Target Cells ◽  
Functional Assay ◽  
Cell Functions ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Chimeric antigen receptor (CAR) T-cell immunotherapy still faces many challenges in the treatment of solid tumors, one of which is T-cell dysfunction or exhaustion. Immunomodulator lenalidomide may improve CAR T-cell function. In this study, the effects of lenalidomide on CAR T-cell functions (cytotoxicity, cytokine secretion, and cell proliferation) were investigated. Two different CAR T cells (CD133-specific CAR and HER2-specific CAR) were prepared, and the corresponding target cells including human glioma cell line U251 CD133-OE that overexpress CD133 and human breast cancer cell line MDA-MB-453 were used for functional assay. We found that lenalidomide promoted the killing of U251 CD133-OE by CD133-CAR T cells, the cytokine secretion, and the proliferation of CD133-CAR T cells. Lenalidomide also enhanced the cytotoxicity against MDA-MB-453 and the cytokine secretion of HER2-CAR T cells but did not affect their proliferation significantly. Furthermore, lenalidomide may regulate the function of CAR T cells by inducing the degradation of transcription factors Ikaros and Aiolos.

scholarly journals Migration ofAntigen-Specific T Cells Away from CXCR4-Binding Human ImmunodeficiencyVirus Type 1gp120

2004 ◽  
Vol 78 (10) ◽  
pp. 5184-5193 ◽  
Author(s):  
Diana M. Brainard ◽  
William G. Tharp ◽  
Elva Granado ◽  
Nicholas Miller ◽  
Alicja K. Trocha ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Cell ◽  
Active Movement ◽  
Target Cells ◽  
Cell Mediated Immunity ◽  
Cell Trafficking ◽  
Hiv 1

ABSTRACT Cell-mediated immunity depends in part on appropriate migration and localization of cytotoxic T lymphocytes (CTL), a process regulated by chemokines and adhesion molecules. Many viruses, including human immunodeficiency virus type 1 (HIV-1), encode chemotactically active proteins, suggesting that dysregulation of immune cell trafficking may be a strategy for immune evasion. HIV-1 gp120, a retroviral envelope protein, has been shown to act as a T-cell chemoattractant via binding to the chemokine receptor and HIV-1 coreceptor CXCR4. We have previously shown that T cells move away from the chemokine stromal cell-derived factor 1 (SDF-1) in a concentration-dependent and CXCR4 receptor-mediated manner. Here, we demonstrate that CXCR4-binding HIV-1 X4 gp120 causes the movement of T cells, including HIV-specific CTL, away from high concentrations of the viral protein. This migratory response is CD4 independent and inhibited by anti-CXCR4 antibodies and pertussis toxin. Additionally, the expression of X4 gp120 by target cells reduces CTL efficacy in an in vitro system designed to account for the effect of cell migration on the ability of CTL to kill their target cells. Recombinant X4 gp120 also significantly reduced antigen-specific T-cell infiltration at a site of antigen challenge in vivo. The repellant activity of HIV-1 gp120 on immune cells in vitro and in vivo was shown to be dependent on the V2 and V3 loops of HIV-1 gp120. These data suggest that the active movement of T cells away from CXCR4-binding HIV-1 gp120, which we previously termed fugetaxis, may provide a novel mechanism by which HIV-1 evades challenge by immune effector cells in vivo.

scholarly journals Virus-Specific CD4+ T Cells Eliminate Borna Disease Virus from the Brain via Induction of Cytotoxic CD8+T Cells

1998 ◽  
Vol 72 (5) ◽  
pp. 4387-4395 ◽  
Author(s):  
Kerstin Nöske ◽  
Thomas Bilzer ◽  
Oliver Planz ◽  
Lothar Stitz
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Disease Virus ◽  
Target Cells ◽  
Borna Disease Virus ◽  
Infected Control ◽  
Low Level ◽  
The Brain ◽  
Borna Disease

ABSTRACT Persistent Borna disease virus infection of the brain can be prevented by treatment of naive rats with a virus-specific CD4+ T-cell line prior to infection. In rats receiving this treatment, only a transient low-level encephalitis was seen compared to an increasingly inflammatory reaction in untreated infected control rats. Virus replication was found in the brain for several days after infection before the virus was cleared from the central nervous system. The loss of infectivity from the brain was confirmed by negative results by reverse transcription-PCR with primers for mRNA, by in situ hybridization for both genomic and mRNA, and by immunohistology. Most importantly, in vitro assays revealed that the T-cell line used for transfusion had no cytotoxic capacity. The kinetics of virus clearance were paralleled by the appearance of CD8+ T cells and the expression of perforin in the brain. Testing of lymphocytes isolated from the brains of CD4+T-cell-treated rats after challenge revealed high cytotoxic activity due to the presence of CD8+ cytotoxic T cells at time points when brain lymphocytes from infected control rats induced low-level cytolysis of target cells. Neutralizing antiviral antibodies and gamma interferon were shown not to be involved in the elimination of virus from the brain.

scholarly journals A two-color haploid genetic screen identifies novel host factors involved in HIV latency

2021 ◽  
Author(s):  
Michael D Röling ◽  
Mahsa Mollapour Sisakht ◽  
Enrico Ne ◽  
Panagiotis Moulos ◽  
Mateusz Stoszko ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Cd4 T Cells ◽  
Genetic Screen ◽  
Host Factors ◽  
Hiv Latency ◽  
Novel Host ◽  
Latent Hiv ◽  
Hiv 1

AbstractTo identify novel host factors as putative targets to reverse HIV latency, we performed an insertional mutagenesis genetic screen in a latently HIV-1-infected pseudo-haploid KBM7 cell line (Hap-Lat). Following mutagenesis, insertions were mapped to the genome and bioinformatic analysis resulted in the identification of 69 candidate host genes involved in maintaining HIV-1 latency. A select set of candidate genes was functionally validated using shRNA mediated depletion in latent HIV-1 infected J-Lat A2 and 11.1 T cell lines. We confirmed ADK, CHD9, CMSS1, EVI2B, EXOSC8, FAM19A, GRIK5, IRF2BP2, NF1, and USP15 as novel host factors involved in the maintenance of HIV latency. Chromatin immunoprecipitation assays indicated that CHD9, a Chromodomain Helicase DNA-binding protein, maintains HIV latency via direct association with the HIV 5’LTR, and its depletion results in increased histone acetylation at the HIV-1 promoter, concomitant with HIV-1 latency reversal. FDA-approved inhibitors 5-Iodotubercidin, Trametinib, and Topiramate, targeting ADK, NF1, and GRIK5, respectively were characterized for their latency reversal potential. While 5-Iodotubercidin exhibited significant cytotoxicity in both J-Lat and primary CD4+ T cells, Trametinib reversed latency in J-Lat cells but not in latently HIV-1-infected primary CD4+ T cells. Crucially, Topiramate reversed latency in cell-line models and latently infected primary CD4+ T cells, without inducing T cell activation or significant toxicity. Thus, using an adaptation of a haploid forward genetic screen, we identified novel and druggable host factors contributing to HIV-1 latency.ImportanceA reservoir of latent HIV-1-infected cells persists in the presence of combination antiretroviral therapy (cART), representing a major obstacle for viral eradication. Reactivation of the latent HIV-1 provirus is part of curative strategies which aim to promote clearance of the infected cells. Using a two-color haploid screen, we identified 69 candidate genes as latency maintaining host factors and functionally validated a subset of 10 of those in additional T-cell based cell line models of HIV-1 latency. We further demonstrated that CHD9 is associated with HIV-1’s promoter, the 5’LTR while this association is lost upon reactivation. Additionally, we characterized the latency reversal potential of FDA compounds targeting ADK, NF1, and GRIK5 and identify the GRIK5 inhibitor Topiramate as a viable latency reversal agent with clinical potential.

scholarly journals OX40 Stimulation by gp34/OX40 Ligand Enhances Productive Human Immunodeficiency Virus Type 1 Infection

2001 ◽  
Vol 75 (15) ◽  
pp. 6748-6757 ◽  
Author(s):  
Yoshiaki Takahashi ◽  
Yuetsu Tanaka ◽  
Atsuya Yamashita ◽  
Yoshio Koyanagi ◽  
Masataka Nakamura ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cell Leukemia Virus Type ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT OX40 is a member of the tumor necrosis factor (TNF) receptor superfamily and known to be an important costimulatory molecule expressed on activated T cells. To investigate the role of costimulation of OX40 in human immunodeficiency virus type 1 (HIV-1) infection by its natural ligand, gp34, the OX40-transfected ACH-2 cell line, ACH-2/OX40, chronically infected with HIV-1, was cocultured with paraformaldehyde (PFA)-fixed gp34-transfected mouse cell line, SV-T2/gp34. The results showed that HIV-1 production was strongly induced. This was followed by apparent apoptosis, and both processes were specifically inhibited by the gp34-specific neutralizing monoclonal antibody 5A8. Endogenous TNF alpha (TNF-α) and TNF-β production were not involved in the enhanced HIV-1 production. Furthermore, enhanced HIV-1 transcription in gp34-stimulated ACH-2/OX40 cells was dependent on the κB site of the HIV-1 long terminal repeat, and the OX40-gp34 interaction activated NF-κB consisting of p50 and p65 subunits. When primary activated CD4+ T cells acutely infected with HIV-1NL4-3 (CXCR4-using T-cell-line-tropic) were cocultured with PFA-fixed gp34+ human T-cell leukemia virus type 1-bearing MT-2 cells or SV-T2/gp34 cells, HIV-1 production was also markedly enhanced. The enhancement was again significantly inhibited by 5A8. The present study first shows that OX40-gp34 interaction stimulates HIV-1 expression and suggests that OX40 triggering by gp34 may play an important role in enhancing HIV-1 production in both acutely and latently infected CD4+ T cells in vivo.

scholarly journals Primary HIV-1 Strains Use Nef To Downmodulate HLA-E Surface Expression

2019 ◽  
Vol 93 (20) ◽  
Author(s):  
Thomas van Stigt Thans ◽  
Janet I. Akko ◽  
Annika Niehrs ◽  
Wilfredo F. Garcia-Beltran ◽  
Laura Richert ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Nk Cell ◽  
Cytoplasmic Tail ◽  
Cytotoxic T Cell ◽  
Cell Recognition ◽  
T Cell Recognition ◽  
Infected Cells ◽  
Hiv 1

ABSTRACTHuman immunodeficiency virus type 1 (HIV-1) has evolved elaborate ways to evade immune cell recognition, including downregulation of classical HLA class I (HLA-I) from the surfaces of infected cells. Recent evidence identified HLA-E, a nonclassical HLA-I, as an important part of the antiviral immune response to HIV-1. Changes in HLA-E surface levels and peptide presentation can prompt both CD8+T-cell and natural killer (NK) cell responses to viral infections. Previous studies reported unchanged or increased HLA-E levels on HIV-1-infected cells. Here, we examined HLA-E surface levels following infection of CD4+T cells with primary HIV-1 strains and observed that a subset downregulated HLA-E. Two primary strains of HIV-1 that induced the strongest reduction in surface HLA-E expression were chosen for further testing. Expression of single Nef or Vpu proteins in a T-cell line, as well as tail swap experiments exchanging the cytoplasmic tail of HLA-A2 with that of HLA-E, demonstrated that Nef modulated HLA-E surface levels and targeted the cytoplasmic tail of HLA-E. Furthermore, infection of primary CD4+T cells with HIV-1 mutants showed that a lack of functional Nef (and Vpu to some extent) impaired HLA-E downmodulation. Taken together, the results of this study demonstrate for the first time that HIV-1 can downregulate HLA-E surface levels on infected primary CD4+T cells, potentially rendering them less vulnerable to CD8+T-cell recognition but at increased risk of NKG2A+NK cell killing.IMPORTANCEFor almost two decades, it was thought that HIV-1 selectively downregulated the highly expressed HLA-I molecules HLA-A and HLA-B from the cell surface in order to evade cytotoxic-T-cell recognition, while leaving HLA-C and HLA-E molecules unaltered. It was stipulated that HIV-1 infection thereby maintained inhibition of NK cells via inhibitory receptors that bind HLA-C and HLA-E. This concept was recently revised when a study showed that primary HIV-1 strains reduce HLA-C surface levels, whereas the cell line-adapted HIV-1 strain NL4-3 lacks this ability. Here, we demonstrate that infection with distinct primary HIV-1 strains results in significant downregulation of surface HLA-E levels. Given the increasing evidence for HLA-E as an important modulator of CD8+T-cell and NKG2A+NK cell functions, this finding has substantial implications for future immunomodulatory approaches aimed at harnessing cytotoxic cellular immunity against HIV.

scholarly journals The B-Oligomer of Pertussis Toxin Deactivates Cc Chemokine Receptor 5 and Blocks Entry of M-Tropic HIV-1 Strains

1999 ◽  
Vol 190 (5) ◽  
pp. 597-606 ◽  
Author(s):  
Massimo Alfano ◽  
Helena Schmidtmayerova ◽  
Carol-Ann Amella ◽  
Tatiana Pushkarsky ◽  
Michael Bukrinsky
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Surface ◽  
Pertussis Toxin ◽  
Chemokine Receptor ◽  
Viral Envelope ◽  
Cell Surface Expression ◽  
Target Cells ◽  
Peripheral Blood Mononuclear ◽  
Hiv 1

Infection of target cells by HIV-1 requires initial binding interactions between the viral envelope glycoprotein gp120, the cell surface protein CD4, and one of the members of the seven-transmembrane G protein–coupled chemokine receptor family. Most primary isolates (R5 strains) use chemokine receptor CCR5, but some primary syncytium-inducing, as well as T cell line–adapted, strains (X4 strains) use the CXCR4 receptor. Signaling from both CCR5 and CXCR4 is mediated by pertussis toxin (PTX)-sensitive Gi proteins and is not required for HIV-1 entry. Here, we show that the PTX holotoxin as well as its binding subunit, B-oligomer, which lacks Gi-inhibitory activity, blocked entry of R5 but not X4 strains into primary T lymphocytes. Interestingly, B-oligomer inhibited virus production by peripheral blood mononuclear cell cultures infected with either R5 or X4 strains, indicating that it can affect HIV-1 replication at both entry and post-entry levels. T cells treated with B-oligomer did not initiate signal transduction in response to macrophage inflammatory protein (MIP)-1β or RANTES (regulated upon activation, normal T cell expressed and secreted); however, cell surface expression of CCR5 and binding of MIP-1β or HIV-1 to such cells were not impaired. The inhibitory effect of B-oligomer on signaling from CCR5 and on entry of R5 HIV-1 strains was reversed by protein kinase C (PKC) inhibitors, indicating that B-oligomer activity is mediated by signaling events that involve PKC. B-oligomer also blocked cocapping of CCR5 and CD4 induced by R5 HIV-1 in primary T cells, but did not affect cocapping of CXCR4 and CD4 after inoculation of the cultures with X4 HIV-1. These results suggest that the B-oligomer of PTX cross-deactivates CCR5 to impair its function as a coreceptor for HIV-1.

scholarly journals Contact-Induced Mitochondrial Polarization Supports HIV-1 Virological Synapse Formation

2014 ◽  
Vol 89 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Elisabetta Groppelli ◽  
Shimona Starling ◽  
Clare Jolly
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Virological Synapse ◽  
Cell Contact ◽  
Target Cells ◽  
Cell Contacts ◽  
Cell Spread ◽  
Hiv 1 ◽  
Cell Cell

ABSTRACTRapid HIV-1 spread between CD4 T lymphocytes occurs at retrovirus-induced immune cell contacts called virological synapses (VS). VS are associated with striking T cell polarization and localized virus budding at the site of contact that facilitates cell-cell spread. In addition to this, spatial clustering of organelles, including mitochondria, to the contact zone has been previously shown. However, whether cell-cell contact specifically induces dynamic T cell remodeling during VS formation and what regulates this process remain unclear. Here, we report that contact between an HIV-1-infected T cell and an uninfected target T cell specifically triggers polarization of mitochondria concomitant with recruitment of the major HIV-1 structural protein Gag to the site of cell-cell contact. Using fixed and live-cell imaging, we show that mitochondrial and Gag polarization in HIV-1-infected T cells occurs within minutes of contact with target T cells, requires the formation of stable cell-cell contacts, and is an active, calcium-dependent process. We also find that perturbation of mitochondrial polarization impairs cell-cell spread of HIV-1 at the VS. Taken together, these data suggest that HIV-1-infected T cells are able to sense and respond to contact with susceptible target cells and undergo dynamic cytoplasmic remodeling to create a synaptic environment that supports efficient HIV-1 VS formation between CD4 T lymphocytes.IMPORTANCEHIV-1 remains one of the major global health challenges of modern times. The capacity of HIV-1 to cause disease depends on the virus's ability to spread between immune cells, most notably CD4 T lymphocytes. Cell-cell transmission is the most efficient way of HIV-1 spread and occurs at the virological synapse (VS). The VS forms at the site of contact between an infected cell and an uninfected cell and is characterized by polarized assembly and budding of virions and clustering of cellular organelles, including mitochondria. Here, we show that cell-cell contact induces rapid recruitment of mitochondria to the contact site and that this supports efficient VS formation and consequently cell-cell spread. Additionally, we observed that cell-cell contact induces a mitochondrion-dependent increase in intracellular calcium, indicative of cellular signaling. Taken together, our data suggest that VS formation is a regulated process and thus a potential target to block HIV-1 cell-cell spread.

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