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Antiplatelet Effects of Clopidogrel Vs Aspirin in Virologically Controlled HIV: A Randomized Controlled Trial

Marcantoni, Emanuela; Garshick, Michael S.; Schwartz, Tamar; Ratnapala, Nicole; Cambria, Matthew; Dann, Rebecca; O'Brien, Meagan; Heguy, Adriana; Berger, Jeffrey S.
Patients with HIV exhibit platelet activation and increased risk of cardiovascular disease, the prevention of which is not fully known. Fifty-five HIV-positive patients were randomized to clopidogrel, aspirin, or no-treatment for 14 days, and the platelet phenotype and ability to induce endothelial inflammation assessed. Clopidogrel as opposed to aspirin and no-treatment reduced platelet activation (P-selectin and PAC-1 expression). Compared with baseline, platelet-induced proinflammatory transcript expression of cultured endothelial cells were reduced in those assigned to clopidogrel, with no change in the aspirin and no-treatment arms. In HIV, clinical trials of clopidogrel to prevent cardiovascular disease are warranted. (Antiplatelet Therapy in HIV; NCT02559414)
SCOPUS:85141772782
ISSN: 2452-302x
CID: 5370232

Platelet Transcriptome Profiling in HIV and ATP-Binding Cassette Subfamily C Member 4 (ABCC4) as a Mediator of Platelet Activity

Marcantoni, Emanuela; Allen, Nicole; Cambria, Matthew R; Dann, Rebecca; Cammer, Michael; Lhakhang, Tenzin; O'Brien, Meagan P; Kim, Benjamin; Worgall, Tilla; Heguy, Adriana; Tsirigos, Aristotelis; Berger, Jeffrey S
An unbiased platelet transcriptome profile identified ATP binding cassette subfamily C member 4 (ABCC4) as a novel mediator of platelet activity in virologically suppressed human immunodeficiency virus (HIV)-infected subjects on antiretroviral therapy. Using ex vivo and in vitro cellular and molecular assays we demonstrated that ABCC4 regulated platelet activation by altering granule release and cyclic nucleotide homeostasis through a cAMP-protein kinase A (PKA)-mediated mechanism. Platelet ABCC4 inhibition attenuated platelet activation and effector cell function by reducing the release of inflammatory mediators, such as sphingosine-1-phosphate. ABCC4 inhibition may represent a novel antithrombotic strategy in HIV-infected subjects on antiretroviral therapy.
PMCID:6058944
PMID: 30062189
ISSN: 2452-302x
CID: 3217022

A Randomized Placebo Controlled Trial of Aspirin Effects on Immune Activation in Chronically Human Immunodeficiency Virus-Infected Adults on Virologically Suppressive Antiretroviral Therapy

O'Brien, Meagan P; Hunt, Peter W; Kitch, Douglas W; Klingman, Karin; Stein, James H; Funderburg, Nicholas T; Berger, Jeffrey S; Tebas, Pablo; Clagett, Brian; Moisi, Daniela; Utay, Netanya S; Aweeka, Fran; Aberg, Judith A
BACKGROUND: Immune activation persists despite suppressive antiretroviral therapy (ART) in human immunodeficiency virus (HIV) infection and predicts non-Acquired Immune Deficiency Syndrome (AIDS) comorbidities including cardiovascular disease. Activated platelets play a key role in atherothrombosis and inflammation, and platelets are hyperactivated in chronic HIV infection. Aspirin is a potent inhibitor of platelet activation through the cyclooxygenase-1 (COX-1) pathway. We hypothesized that platelet activation contributes to immune activation and that aspirin would reduce immune activation and improve endothelial function in ART-suppressed HIV-infected individuals. METHODS: In this prospective, double-blind, randomized, placebo-controlled 3-arm trial of 121 HIV-infected participants on suppressive ART for >48 weeks, we evaluated the effects of 12 weeks of daily aspirin 100 mg, aspirin 300 mg, or placebo on soluble and cellular immune activation markers, flow-mediated dilation (FMD) of the brachial artery, and serum thromboxane B2, a direct readout of platelet COX-1 inhibition. RESULTS: The 300-mg and 100-mg aspirin arms did not differ from placebo in effects on soluble CD14, interleukin (IL)-6, soluble CD163, D-dimer, T-cell or monocyte activation, or the other immunologic endpoints measured. Endothelial function, as measured by FMD, also was not significantly changed when comparing the 300-mg and 100-mg aspirin arms to placebo. CONCLUSIONS: Aspirin treatment for 12 weeks does not have a major impact on soluble CD14, IL-6, soluble CD163, D-dimer, T-cell or monocyte activation, or FMD, suggesting that inhibition of COX-1-mediated platelet activation does not significantly improve HIV-related immune activation and endothelial dysfunction. Although future studies are needed to further identify the causes and consequences of platelet activation in ART-treated HIV infection, interventions other than COX-1 inhibition will need to be explored to directly reduce immune activation in treated HIV infection.
PMCID:5414028
PMID: 28480270
ISSN: 2328-8957
CID: 2548822

Soluble CD40 ligand contributes to dendritic cell-mediated T-cell dysfunction in HIV-1 infection

Miller, Elizabeth A; Gopal, Ramya; Valdes, Vanessa; Berger, Jeffrey S; Bhardwaj, Nina; O'Brien, Meagan P
OBJECTIVE: Plasma soluble CD40 ligand (sCD40L) is increased during HIV-1 infection, but it is unknown whether it circulates in monomeric or multimeric forms, and whether the circulating forms have differential effects on myeloid dendritic cell function and adaptive regulation. DESIGN: sCD40L forms were measured in plasma samples from HIV-infected donors. The effects of sCD40L forms on dendritic cell function were measured in vitro. METHODS: To delineate which forms of sCD40L are present in plasma from HIV-infected donors, immunoblots were performed following enrichment of plasma for medium and low-abundance proteins. Dendritic cells from seronegative donors were exposed to multiple forms of sCD40L prior to Toll-like receptor stimulation and dendritic cell function and adaptive regulation was assessed in vitro. RESULTS: Monomeric and multimeric forms of sCD40L were identified in plasma from antiretroviral therapy-treated HIV-infected donors. Although monomeric and multimeric forms of sCD40L had differential effects on dendritic cell activation when given alone, both strongly suppressed secretion of the Th1 skewing cytokine, interleukin-12, upon subsequent Toll-like receptor stimulation. Furthermore, dendritic cells exposed to both monomeric and multimeric sCD40L induced regulatory T-cell formation and T-cell anergy. CONCLUSION: Elevated sCD40L during HIV infection impairs dendritic cell function, contributing to innate and adaptive immune dysfunction. Antiretroviral adjunctive therapies that decrease sCD40L may provide immune modulatory benefits.
PMCID:4478195
PMID: 26091297
ISSN: 1473-5571
CID: 1631122

Attenuated Listeria monocytogenes Vectors Overcome Suppressive Plasma Factors during HIV Infection to Stimulate Myeloid Dendritic Cells to Promote Adaptive Immunity and Reactivation of Latent Virus

Miller, Elizabeth; Spadaccia, Meredith; Norton, Thomas David; Demmler, Morgan; Gopal, Ramya; O'Brien, Meagan; Landau, Nathaniel R; Dubensky, Thomas; Lauer, Peter; Brockstedt, Dirk; Bhardwaj, Nina
HIV-1 infection is characterized by myeloid dendritic cell (DC) dysfunction which blunts their responsiveness to vaccine adjuvants. We previously showed that non-viral factors in HIV-seropositive plasma are partially responsible for mediating this immune suppression. In this study we investigated recombinant Listeria monocytogenes (Lm) vectors, which naturally infect and potently activate DCs from seronegative donors, as a means to overcome DC dysfunction associated with HIV infection. Monocyte-derived DCs were cocultured with plasma from HIV-infected donors (HIV-moDCs) to induce a dysregulated state and infected with an attenuated, non-replicative vaccine strain of Lm expressing full length clade B consensus gag (KBMA Lm-gag). Lm infection stimulated cytokine secretion (IL-12p70, TNFalpha, IL-6) and Th-1 skewing of allogeneic naive CD4 T cells by HIV-moDCs, in contrast to the suppressive effects observed by HIV plasma on moDCs upon toll-like receptor ligand stimulation. Upon coculture of KBMA Lm-gag-infected moDCs from HIV-infected donors with autologous cells, expansion of polyfunctional, gag-specific CD8+ T cells was observed. Reactivation of latent proviruses by moDCs following Lm infection was also observed in models of HIV latency in a TNFalpha-dependent manner. These findings reveal the unique ability of Lm vectors to contend with dysregulation of HIV-moDCs , while simultaneously possessing the capacity to activate latent virus. Concurrent stimulation of innate and adaptive immunity and disruption of latency may be an approach to reduce the pool of latently infected cells during HIV infection. Further study of Lm vectors as part of therapeutic vaccination and eradication strategies may advance this evolving field.
PMCID:4287309
PMID: 25376024
ISSN: 0889-2229
CID: 1349952

HIV Type 1 Infection of Plasmacytoid and Myeloid Dendritic Cells Is Restricted by High Levels of SAMHD1 and Cannot be Counteracted by Vpx

Bloch, Nicolin; O'Brien, Meagan; Norton, Thomas D; Polsky, Sylvie B; Bhardwaj, Nina; Landau, Nathaniel R
Abstract Dendritic cells are professional antigen-presenting cells of the immune system and are major producers of type-I interferon. Their role in HIV-1 infection is not well understood. They express CD4 and CCR5 yet appear to be resistant to infection. In culture, infection of the cells with HIV-1 is inhibited by the host cell restriction factor SAMHD1. Lentiviruses such as HIV-2/SIVmac counteract the restriction by encoding Vpx, a virion-packaged accessory protein that induces the proteasomal degradation of SAMHD1. In this study we investigated SAMHD1-mediated restriction in the two major dendritic cell subsets: plasmacytoid dendritic cells (pDC) and myeloid dendritic cells (mDC). The cells were highly resistant to HIV-1 and expressed high levels of SAMHD1. SAMHD1 amino acid residue T592, a target of CDK1 phosphorylation, was unphosphorylated, corresponding to the antiviral form of the enzyme. The resistance to infection was not counteracted by Vpx and SAMHD1 was not degraded in these cells. Treatment of pDCs with a cocktail of antibodies that blocked type-I interferon signaling partially restored the ability of Vpx to induce SAMHD1 degradation and caused the cells to become partially permissive to infection. pDCs and mDCs responded to HIV-1 virions by inducing an innate immune response but did not appear to sense newly produced Gag protein. The findings suggest that in vivo, dendritic cells serve as sentinels to alert the immune system to the virus but do not themselves become infected by virtue of high levels of SAMHD1.
PMCID:3910455
PMID: 23924154
ISSN: 0889-2229
CID: 674952

Aspirin attenuates platelet activation and immune activation in HIV-1-infected subjects on antiretroviral therapy: a pilot study

O'Brien, Meagan; Montenont, Emilie; Hu, Liang; Nardi, Michael A; Valdes, Vanessa; Merolla, Michael; Gettenberg, Gabrielle; Cavanagh, Karen; Aberg, Judith A; Bhardwaj, Nina; Berger, Jeffrey S
BACKGROUND: Mechanisms for increased cardiovascular risk in HIV-1-infected adults are incompletely understood, but platelet activation and immune activation leading to a prothrombotic state have been proposed as significant contributors. Aspirin has antiplatelet and immunomodulatory properties. We explored whether 1 week of low-dose aspirin attenuates platelet activation and immune activation in HIV-1-infected and virologically suppressed adults on antiretroviral therapy. METHODS: Platelet activation and immune activation were measured in HIV-1-infected subjects virologically suppressed on antiretroviral therapy and controls before and after 1 week of low-dose aspirin. RESULTS: Compared with control subjects, HIV-1-infected subjects had increased platelet activation, as measured by spontaneous platelet aggregation and aggregation in response to adenosine diphosphate, collagen, and arachidonic acid. After aspirin therapy, percent aggregation decreased similarly in both HIV-1-infected and control subjects to all platelet agonists tested except aggregation in response to arachidonic acid, which remained elevated in the HIV-1-infected group. HIV-1-infected subjects exhibited increased markers of T-cell activation (CD38 and HLA-DR) and monocyte activation (sCD14), which decreased after 1 week of aspirin therapy. Moreover, leukocyte responses to Toll-like receptor stimulation were enhanced after 1 week of aspirin therapy. In vitro studies showed that HIV-1 plasma could activate healthy platelets, which in turn activated monocytes, implicating a direct role for activated platelets in immune activation. CONCLUSIONS: Our data demonstrate that heightened platelet activation and immune activation in treated HIV-1 disease are attenuated by 1 week of aspirin therapy. Aspirin should be further studied for its antithrombotic and immunomodulatory benefits in treated HIV-1 disease.
PMCID:3756489
PMID: 23406976
ISSN: 1525-4135
CID: 464852

Phenotypic properties of transmitted founder HIV-1

Parrish, Nicholas F; Gao, Feng; Li, Hui; Giorgi, Elena E; Barbian, Hannah J; Parrish, Erica H; Zajic, Lara; Iyer, Shilpa S; Decker, Julie M; Kumar, Amit; Hora, Bhavna; Berg, Anna; Cai, Fangping; Hopper, Jennifer; Denny, Thomas N; Ding, Haitao; Ochsenbauer, Christina; Kappes, John C; Galimidi, Rachel P; West, Anthony P Jr; Bjorkman, Pamela J; Wilen, Craig B; Doms, Robert W; O'Brien, Meagan; Bhardwaj, Nina; Borrow, Persephone; Haynes, Barton F; Muldoon, Mark; Theiler, James P; Korber, Bette; Shaw, George M; Hahn, Beatrice H
Defining the virus-host interactions responsible for HIV-1 transmission, including the phenotypic requirements of viruses capable of establishing de novo infections, could be important for AIDS vaccine development. Previous analyses have failed to identify phenotypic properties other than chemokine receptor 5 (CCR5) and CD4+ T-cell tropism that are preferentially associated with viral transmission. However, most of these studies were limited to examining envelope (Env) function in the context of pseudoviruses. Here, we generated infectious molecular clones of transmitted founder (TF; n = 27) and chronic control (CC; n = 14) viruses of subtypes B (n = 18) and C (n = 23) and compared their phenotypic properties in assays specifically designed to probe the earliest stages of HIV-1 infection. We found that TF virions were 1.7-fold more infectious (P = 0.049) and contained 1.9-fold more Env per particle (P = 0.048) compared with CC viruses. TF viruses were also captured by monocyte-derived dendritic cells 1.7-fold more efficiently (P = 0.035) and more readily transferred to CD4+ T cells (P = 0.025). In primary CD4+ T cells, TF and CC viruses replicated with comparable kinetics; however, when propagated in the presence of IFN-alpha, TF viruses replicated to higher titers than CC viruses. This difference was significant for subtype B (P = 0.000013) but not subtype C (P = 0.53) viruses, possibly reflecting demographic differences of the respective patient cohorts. Together, these data indicate that TF viruses are enriched for higher Env content, enhanced cell-free infectivity, improved dendritic cell interaction, and relative IFN-alpha resistance. These viral properties, which likely act in concert, should be considered in the development and testing of AIDS vaccines.
PMCID:3637789
PMID: 23542380
ISSN: 0027-8424
CID: 349162

Plasmacytoid Dendritic Cells in HIV Infection

O'Brien, Meagan; Manches, Olivier; Bhardwaj, Nina
Plasmacytoid dendritic cells (pDCs) are innate immune cells that are specialized to produce interferon-alpha (IFNalpha) and participate in activating adaptive immune responses. Although IFNalpha inhibits HIV-1 (HIV) replication in vitro, pDCs may act as inflammatory and immunosuppressive dendritic cells (DCs) rather than classical antigen-presenting cells during chronic HIV infection in vivo, contributing more to HIV pathogenesis than to protection. Improved understanding of HIV-pDC interactions may yield potential new avenues of discovery to prevent HIV transmission, to blunt chronic immune activation and exhaustion, and to enhance beneficial adaptive immune responses. In this chapter we discuss pDC biology, including pDC development from progenitors, trafficking and localization of pDCs in the body, and signaling pathways involved in pDC activation. We focus on the role of pDCs in HIV transmission, chronic disease progression and immune activation, and immunosuppression through regulatory T cell development. Lastly, we discuss potential future directions for the field which are needed to strengthen our current understanding of the role of pDCs in HIV transmission and pathogenesis.
PMCID:3713461
PMID: 22975872
ISSN: 0065-2598
CID: 178229

Plasma Factors During Chronic HIV-1 Infection Impair IL-12 Secretion by Myeloid Dendritic Cells via a Virus-Independent Pathway

Miller, Elizabeth A; Spadaccia, Meredith R; O'brien, Meagan P; Rolnitzky, Linda; Sabado, Rachel; Manches, Olivier; Frleta, Davor; Bhardwaj, Nina
OBJECTIVE: : Myeloid dendritic cell (mDC) dysfunction during HIV infection may hinder the formation of both innate and adaptive immune responses and contribute to pathogenesis. Our objective was to determine whether circulating factors during chronic HIV infection impair mDC function with respect to secretion of IL-12, a pro-Th1 cytokine, and T-cell stimulatory capacity. Particular focus was placed on the effect of combination antiretroviral therapy (cART) and the role of HIV itself on mDC function. METHODS: : Monocyte-derived DC (moDC) from uninfected donors were exposed to plasma from HIV-infected individuals before Toll-like receptor (TLR) stimulation. Cytokine secretion was measured via cytokine bead arrays, and T-cell proliferation and IFNgamma secretion was evaluated after coculture with naive CD4 T cells. Expression of genes central to TLR-mediated signal transduction was analyzed via quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) arrays and western blot. RESULTS: : Exposure of monocyte-derived DC to plasma from untreated HIV-infected donors suppressed secretion of IL-12, and impaired Th1-skewing of CD4 T cells. The suppressive effect was less by plasma donors receiving cART. Removal of virus from plasma did not relieve suppression nor was IL-12 secretion decreased on addition of HIV to control plasma. On a transcriptional level, decreased expression of IKKbeta, a key regulator in the TLR/NF-kappaB signaling pathway, corresponded to suppressed cytokine secretion. CONCLUSIONS: : Plasma factors during chronic HIV infection impair mDC function in a manner that likely impacts the formation of immune responses to HIV, opportunistic pathogens, and vaccines. Despite partial alleviation by cART, this suppression was not directly mediated by HIV.
PMCID:3508089
PMID: 22902724
ISSN: 1525-4135
CID: 184782