Specific ActivationIn Vivoof HIV-1 by a Bromodomain Inhibitor from Monocytic Cells in Humanized Mice under Antiretroviral Therapy

ABSTRACTCombination antiretroviral therapy (cART) effectively suppresses HIV-1 replication and enables HIV‑infected individuals to live long, productive lives. However, the persistence of HIV-1 reservoirs of both T and myeloid cells with latent or low-replicating HIV-1 in patients under cART makes HIV-1 infection an incurable disease. Recent studies have focused on the development of strategies to activate and purge these reservoirs. Bromodomain and extraterminal domain proteins (BETs) are epigenetic readers involved in modulating gene expression. Several bromodomain inhibitors (BETi) are reported to activate viral transcriptionin vitroin HIV-1 latency cell lines in a P-TEFb (CDK9/cyclin T1)-dependent manner. Little is known about BETi efficacy in activating HIV-1 reservoir cells under cARTin vivo. Here we report that a BETi (I-BET151) efficiently activated HIV-1 reservoirs under effective cART in humanized micein vivo. Interestingly, I-BET151 during suppressive cARTin vivoactivated HIV-1 gene expression only in monocytic cells and not in CD4+T cells. We further demonstrate that BETi preferentially enhanced HIV-1 gene expression in monocytic cells rather than in T cells and that whereas CDK9 was involved in activating HIV-1 by I-BET151 in both monocytic and T cells, CDK2 enhanced HIV-1 transcription in monocytic cells but inhibited it in T cells. Our findings reveal a role for CDK2 in differential modulation of HIV-1 gene expression in myeloid cells and in T cells and provide a novel strategy to reactivate monocytic reservoirs with BETi during cART.IMPORTANCEBromodomain inhibitors have been reported to activate HIV-1 transcriptionin vitro, but their effect on activation of HIV-1 reservoirs during cARTin vivois unclear. We found that BETi (I-BET151) treatment reactivated HIV-1 gene expression in humanized mice during suppressive cART. Interestingly, I-BET151 preferentially reactivated HIV-1 gene expression in monocytic cells, but not in CD4 T cells, in cART-treated mice. Furthermore, I-BET151 significantly increased HIV-1 transcription in monocytic cells, but not in HIV-1-infected CD4 T cells, via CDK2-dependent mechanisms. Our findings suggest that BETi can preferentially activate monocytic HIV-1 reservoir cells and that a combination of reservoir activation agents targeting different cell types and pathways is needed to achieve reactivation of different HIV-1 reservoir cells during cART.

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Specific activation of HIV-1 from monocytic reservoir cells by bromodomain inhibitor in humanized mice in vivo

10.1101/375535 ◽

2018 ◽

Cited By ~ 1

Author(s):

Guangming Li ◽

Zheng Zhang ◽

Natalia Reszka-Blanco ◽

Feng Li ◽

Liqun Chi ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

Cd4 T Cells ◽

Humanized Mice ◽

Viral Transcription ◽

Dependent Manner ◽

Monocytic Cells ◽

Hiv 1

ABSTRACTThe combination antiretroviral therapy (cART) effectively suppresses HIV-1 infection and enables HIV-infected individuals to live long productive lives. However, the persistence of HIV-1 reservoir cells with latent or low-replicating HIV-1 in patients under cART make HIV-1 infection an incurable disease. Recent studies have focused on the development of strategies such as epigenetic modulators to activate and purge these reservoirs. Bromodomain inhibitors (BETi) are epigenetic modulating compounds able to activate viral transcription in HIV-1 latency cell lines in a positive transcription elongation factor b (P-TEFb)-dependent manner. Little is known about the efficacy of activating HIV-1 reservoir cells under cART by BETi in vivo. In this study, we seek to test the potential of a BETi (I-BET151) in activating HIV-1 reservoir cells under effective cART in humanized mice in vivo. We discover that I-BET151 efficiently activates HIV-1 transcription in monocytic cells, but not in CD4+T cells, during suppressive cART in vivo. We further reveal that HIV-1 proviruses in monocytic cells are more sensitive to I-BET151 treatment than in T cells in vitro. Finally, we demonstrate that I-BET151-activated viral transcription in monocytic cells is dependent on both CDK2 and CDK9, whereas only CDK9 is involved in activation of HIV-1 by I-BET151 in T cells. Our findings indicate a role of myeloid cells in HIV-1 persistence, and highlights the limitation of measuring or targeting T cell reservoirs alone in terms of HIV-1 cure, as well as provides a potential strategy to reactivate monocytic reservoirs during cART.IMPORTANCEIt has been reported the low level of active P-TEFb critically contributes to the maintenance of HIV-1 latency or low-replication in HIV-1 reservoir cells under cART. Bromodomain inhibitors are used to activate HIV-1 replication in vitro but their effect on activation of the HIV-1 resevoirs with cART in vivo is not clear. We found that BETi (I-BET151) treatment reactivated HIV-1 gene expression in humanized mice during suppressive cART. Interestingly, I-BET151 preferentially reactivated HIV-1 gene expression in monocytic cells, but not in CD4 T cells. Furthermore, I-BET151 significantly increased HIV-1 transcription in monocytic cells, but not in latently infected CD4 T cells, via CDK2-dependent mechanisms. Our findings suggest that BETi can preferentially activate monocytic HIV-1 reservoir cells, and a combination of latency reversal agents targeting different cell types and pathways is needed to achieve reactivation of different HIV-1 reservoir cells during cART.

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Preferential infection and depletion of Mycobacterium tuberculosis–specific CD4 T cells after HIV-1 infection

Journal of Experimental Medicine ◽

10.1084/jem.20100090 ◽

2010 ◽

Vol 207 (13) ◽

pp. 2869-2881 ◽

Cited By ~ 155

Author(s):

Christof Geldmacher ◽

Njabulo Ngwenyama ◽

Alexandra Schuetz ◽

Constantinos Petrovas ◽

Klaus Reither ◽

...

Keyword(s):

T Cells ◽

Mycobacterium Tuberculosis ◽

Hiv Infection ◽

Cd4 T Cells ◽

Staphylococcal Enterotoxin B ◽

Opportunistic Pathogens ◽

Rapid Loss ◽

Hiv 1

HIV-1 infection results in the progressive loss of CD4 T cells. In this study, we address how different pathogen-specific CD4 T cells are affected by HIV infection and the cellular parameters involved. We found striking differences in the depletion rates between CD4 T cells to two common opportunistic pathogens, cytomegalovirus (CMV) and Mycobacterium tuberculosis (MTB). CMV-specific CD4 T cells persisted after HIV infection, whereas MTB-specific CD4 T cells were depleted rapidly. CMV-specific CD4 T cells expressed a mature phenotype and produced very little IL-2, but large amounts of MIP-1β. In contrast, MTB-specific CD4 T cells were less mature, and most produced IL-2 but not MIP-1β. Staphylococcal enterotoxin B–stimulated IL-2–producing cells were more susceptible to HIV infection in vitro than MIP-1β–producing cells. Moreover, IL-2 production was associated with expression of CD25, and neutralization of IL-2 completely abrogated productive HIV infection in vitro. HIV DNA was found to be most abundant in IL-2–producing cells, and least abundant in MIP-1β–producing MTB-specific CD4 T cells from HIV-infected subjects with active tuberculosis. These data support the hypothesis that differences in function affect the susceptibility of pathogen-specific CD4 T cells to HIV infection and depletion in vivo, providing a potential mechanism to explain the rapid loss of MTB-specific CD4 T cells after HIV infection.

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Regulatory T Cells Contribute to HIV-1 Reservoir Persistence in CD4+ T Cells Through Cyclic Adenosine Monophosphate–Dependent Mechanisms in Humanized Mice In Vivo

The Journal of Infectious Diseases ◽

10.1093/infdis/jix547 ◽

2017 ◽

Vol 216 (12) ◽

pp. 1579-1591 ◽

Cited By ~ 10

Author(s):

Guangming Li ◽

Jun-ichi Nunoya ◽

Liang Cheng ◽

Natalia Reszka-Blanco ◽

Li-Chung Tsao ◽

...

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Cd4 T Cells ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Humanized Mice ◽

Hiv 1

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The Interplay of HIV-1 and Macrophages in Viral Persistence

Frontiers in Microbiology ◽

10.3389/fmicb.2021.646447 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chynna M. Hendricks ◽

Thaissa Cordeiro ◽

Ana Paula Gomes ◽

Mario Stevenson

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Viral Persistence ◽

Vital Role ◽

Highly Active ◽

Antiretroviral Therapies ◽

Memory Cd4 T Cells ◽

Hiv 1

HIV-1 has evolved mechanisms to evade host cell immune responses and persist for lifelong infection. Latent cellular reservoirs are responsible for this persistence of HIV-1 despite the powerful effects of highly active antiretroviral therapies (HAART) to control circulating viral load. While cellular reservoirs have been extensively studied, much of these studies have focused on peripheral blood and resting memory CD4+ T cells containing latent HIV-1 provirus; however, efforts to eradicate cellular reservoirs have been stunted by reservoirs found in tissues compartments that are not easily accessible. These tissues contain resting memory CD4+ T cells and tissue resident macrophages, another latent cellular reservoir to HIV-1. Tissue resident macrophages have been associated with HIV-1 infection since the 1980s, and evidence has continued to grow regarding their role in HIV-1 persistence. Specific biological characteristics play a vital role as to why macrophages are latent cellular reservoirs for HIV-1, and in vitro and in vivo studies exhibit how macrophages contribute to viral persistence in individuals and animals on antiretroviral therapies. In this review, we characterize the role and evolutionary advantages of macrophage reservoirs to HIV-1 and their contribution to HIV-1 persistence. In acknowledging the interplay of HIV-1 and macrophages in the host, we identify reasons why current strategies are incapable of eliminating HIV-1 reservoirs and why efforts must focus on eradicating reservoirs to find a future functional cure.

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HIV-1 Vpr- and Reverse Transcription-Induced Apoptosis in Resting Peripheral Blood CD4 T Cells and Protection by Common Gamma-Chain Cytokines

Journal of Virology ◽

10.1128/jvi.01770-15 ◽

2015 ◽

Vol 90 (2) ◽

pp. 904-916 ◽

Cited By ~ 13

Author(s):

Benjamin Trinité ◽

Chi N. Chan ◽

Caroline S. Lee ◽

David N. Levy

Keyword(s):

T Cells ◽

Cell Death ◽

T Cell ◽

Reverse Transcription ◽

Peripheral Blood ◽

Cd4 T Cells ◽

Productive Infection ◽

Hiv 1

ABSTRACTHIV-1 infection leads to the progressive depletion of the CD4 T cell compartment by various known and unknown mechanisms.In vivo, HIV-1 infects both activated and resting CD4 T cells, butin vitro, in the absence of any stimuli, resting CD4 T cells from peripheral blood are resistant to infection. This resistance is generally attributed to an intracellular environment that does not efficiently support processes such as reverse transcription (RT), resulting in abortive infection. Here, we show thatin vitroHIV-1 infection of resting CD4 T cells induces substantial cell death, leading to abortive infection.In vivo, however, various microenvironmental stimuli in lymphoid and mucosal tissues provide support for HIV-1 replication. For example, common gamma-chain cytokines (CGCC), such as interleukin-7 (IL-7), render resting CD4 T cells permissible to HIV-1 infection without inducing T cell activation. Here, we find that CGCC primarily allow productive infection by preventing HIV-1 triggering of apoptosis, as evidenced by early release of cytochromecand caspase 3/7 activation. Cell death is triggered both by products of reverse transcription and by virion-borne Vpr protein, and CGCC block both mechanisms. When HIV-1 RT efficiency was enhanced by SIVmac239 Vpx protein, cell death was still observed, indicating that the speed of reverse transcription and the efficiency of its completion contributed little to HIV-1-induced cell death in this system. These results show that a major restriction on HIV-1 infection in resting CD4 T cells resides in the capacity of these cells to survive the early steps of HIV-1 infection.IMPORTANCEA major consequence of HIV-1 infection is the destruction of CD4 T cells. Here, we show that delivery of virion-associated Vpr protein and the process of reverse transcription are each sufficient to trigger apoptosis of resting CD4 T cells isolated from peripheral blood. While these 2 mechanisms have been previously described in various cell types, we show for the first time their concerted effect in inducing resting CD4 T cell depletion. Importantly, we found that cytokines such as IL-7 and IL-4, which are particularly active in sites of HIV-1 replication, protect resting CD4 T cells from these cytopathic effects and, primarily through this protection, rather than through enhancement of specific replicative steps, they promote productive infection. This study provides important new insights for the understanding of the early steps of HIV-1 infection and T cell depletion.

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Induction of HIV-1 Replication in Latently Infected CD4+ T Cells Using a Combination of Cytokines

Journal of Experimental Medicine ◽

10.1084/jem.188.1.83 ◽

1998 ◽

Vol 188 (1) ◽

pp. 83-91 ◽

Cited By ~ 258

Author(s):

Tae-Wook Chun ◽

Delphine Engel ◽

Stephanie B. Mizell ◽

Linda A. Ehler ◽

Anthony S. Fauci

Keyword(s):

T Cells ◽

Antiretroviral Therapy ◽

Viral Replication ◽

Proinflammatory Cytokines ◽

Cd4 T Cells ◽

Lymphoid Tissues ◽

Tnf Α ◽

Latently Infected ◽

Hiv 1

Although it has been demonstrated that certain cytokines, particularly proinflammatory cytokines, can enhance ongoing viral replication in peripheral blood mononuclear cells (PBMCs) of HIV-1–infected individuals, it is unclear what role these cytokines play in the induction of HIV-1 replication in latently infected, resting CD4+ T cells. This study demonstrates that the in vitro combination of the proinflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α together with the immunoregulatory cytokine IL-2 are potent inducers of viral replication in highly purified, latently infected, resting CD4+ T cells derived from HIV-infected individuals who are antiretroviral therapy–naive as well as those who are receiving highly active antiretroviral therapy (HAART). Viral replication induced by this combination of cytokines was completely suppressed in the presence of HAART in vitro. Given that an array of cytokines, including IL-6, TNF-α, and IL-2, are copiously expressed in the microenvironment of the lymphoid tissues, which harbor the latent viral reservoirs, induction of HIV by this combination of cytokines may in part explain the commonly observed reappearance of detectable plasma viremia in HIV-infected individuals in whom HAART was discontinued. Moreover, since it is likely that these infected cells die upon activation of virus and that HAART prevents spread of virus to adjacent cells, the observation that this combination of cytokines can markedly induce viral replication in this reservoir may have important implications for the activation-mediated diminution of the latent reservoir of HIV in patients receiving HAART.

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CCR5 interaction with HIV-1 Env contributes to Env-induced depletion of CD4 T cells in vitro and in vivo

Retrovirology ◽

10.1186/s12977-016-0255-z ◽

2016 ◽

Vol 13 (1) ◽

Cited By ~ 10

Author(s):

Li-Chung Tsao ◽

Haitao Guo ◽

Jerry Jeffrey ◽

James A. Hoxie ◽

Lishan Su

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Hiv 1

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Overexpression of CD200 Is a Stem Cell-Specific Mechanism of Immune Escape in AML

Blood ◽

10.1182/blood-2020-139434 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 14-15

Author(s):

Shelley Herbrich ◽

Natalia Baran ◽

Gheath Alatrash ◽

Eric Davis ◽

Dongxing Zha ◽

...

Keyword(s):

Gene Expression ◽

Overall Survival ◽

T Cells ◽

Stem Cell ◽

Research Funding ◽

Cytokine Secretion ◽

Humanized Mice ◽

Humanized Mouse

Background: Acute myeloid leukemia (AML) stem cells (LSC), the likely source of relapsed disease, are capable of surviving current standard chemotherapy. Therefore, novel therapeutic approaches specifically engineered to eradicate LSCs are critical for curing AML. We previously introduced a novel bioinformatics approach that harnessed publically available AML gene expression datasets and identified CD200 as significantly over-expressed in LSCs when compared to paired blast cells, as well as when compared to their normal hematopoietic stem cell (HSC) counterparts (Fig 1A; Herbrich et al Blood. 2018; 130:3962). CD200 can identify AML cells with LSC activity in vivo (Ho et al Blood. 2016; 128:1705). Functionally, CD200 has been shown to have an immunosuppressive effect on macrophages (Hoek et al Science. 2000; 290:1768) and NK cells (Coles et al Leukemia. 2012; 26:2148), and correlates with a high prevalence of FOXP3+ regulatory T cells (Coles et al Leukemia. 2012; 26:2146). Additionally, CD200 has been implicated as a poor prognostic marker in AML (Damiani et al Oncotarget. 2015; 6:30212). To date, we have screened 40 primary AML patient samples by flow cytometry, 95% of which are positive for CD200. Methods: To study the functional role of CD200 in AML, we generated a CD200 overexpression model in the human OCI-AML3 cell line (with no basal expression) and characterized changes in proliferation, survival, and gene expression. To examine the immune function of CD200 in AML in vitro, we performed a series of mixed lymphocyte reactions with isolated effector immune cells and target isogenic AML cell lines to assess immune cell-mediated apoptosis, proliferation, and cytokine secretion. To understand the contribution of CD200 immune protection in a physiological setting, we developed a peripheral blood mononuclear cell (PBMC)-humanized mouse in which we tracked the engraftment and overall survival of the CD200+/- OCI-AML3 cells. Lastly, the utility of CD200-blockade using a fully humanized anti-CD200 monoclonal antibody (CD200-IgG1) was evaluated both in vitro and in vivo. Results: In vitro, CD200+ AML significantly inhibited the secretion of inflammatory cytokines and cytotoxic enzymes from healthy PBMCs; a phenomenon that could be largely reversed by blocking the CD200/CD200R interaction with the CD200 antibody (Fig 1B). In vivo, OCI-AML3 CD200+/- cells showed no difference in engraftment, progression, and overall survival in immunodeficient NSG mice (Fig 1C). However, when mice were humanized using healthy PBMCs, CD200+ leukemia progressed rapidly, escaping T cell-mediated elimination, compared to CD200- control leukemic cells (Fig 1D). Cytokine production in PBMC-humanized mice was significantly compromised in those with CD200-expressing leukemia. Transcriptome analysis revealed that T cells from humanized mice exposed to CD200 expressing disease were metabolically quiescent. In humanized mice, CD200-IgG1 therapy eliminated CD200+ AML disease (Fig 1E). The novel CD200-IgG1 antibody also induced potent, specific NK cell-mediated antibody dependent cellular cytotoxicity (ADCC) and macrophage-mediated antibody dependent cellular phagocytosis (ADCP; Fig 1F). Conclusion: We have identified CD200 as a putative stem cell-specific immunomodulatory target that aids in establishing an immunosuppressive microenvironment by significantly suppressing cytokine secretion in response to AML. In a PBMC-humanized mouse model, the presence of cell-surface CD200 was sufficient to protect AML cells from immune-mediated clearance and could be reversed using a blocking anti-CD200 mAb. These findings indicate a utility of CD200 as a novel immune checkpoint target for the development of therapeutic strategies in AML. Disclosures Konopleva: Calithera: Research Funding; Kisoji: Consultancy; AbbVie: Consultancy, Research Funding; Reata Pharmaceutical Inc.;: Patents & Royalties: patents and royalties with patent US 7,795,305 B2 on CDDO-compounds and combination therapies, licensed to Reata Pharmaceutical; Ablynx: Research Funding; Genentech: Consultancy, Research Funding; F. Hoffmann La-Roche: Consultancy, Research Funding; Eli Lilly: Research Funding; Cellectis: Research Funding; Amgen: Consultancy; Stemline Therapeutics: Consultancy, Research Funding; AstraZeneca: Research Funding; Sanofi: Research Funding; Agios: Research Funding; Forty-Seven: Consultancy, Research Funding; Rafael Pharmaceutical: Research Funding; Ascentage: Research Funding.

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