Synergistic Reactivation of Latent HIV Expression by Ingenol-3-Angelate, PEP005, Targeted NF-kB Signaling in Combination with JQ1 Induced p-TEFb Activation.

Although anti-retroviral therapy (ART) is highly effective in suppressing HIV replication, it fails to eradicate the virus from HIV-infected individuals. Stable latent HIV reservoirs are rapidly established early after HIV infection. Therefore, effective strategies for eradication of the HIV reservoirs are urgently needed.

Heat-stable molecule derived from Streptococcus cristatus induces APOBEC3 expression and inhibits HIV-1 replication.

Although most human immunodeficiency virus type 1 (HIV-1) cases worldwide are transmitted through mucosal surfaces, transmission through the oral mucosal surface is a rare event. More than 700 bacterial species have been detected in the oral cavity. Despite great efforts to discover oral inhibitors of HIV, little information is available concerning the anti-HIV activity of oral bacterial components.

Infection of female primary lower genital tract epithelial cells after natural pseudotyping of HIV-1: possible implications for sexual transmission of HIV-1.

The global AIDS pandemic continues to expand and in some regions of the world, such as southern Africa, the prevalence of HIV-1 infection exceeds 20%. The devastating spread of the virus in young women in these countries appears disproportional to overall risk of infection. Regions with high prevalence of HIV-1 are often also highly endemic for other pathogenic viruses including HSV, CMV and HTLV.

Greater ethnic diversity correlates with lower HIV prevalence in Africa: justification for an alloimmunity vaccine.

Purpose: After decades of research, AIDS continues to be a major pandemic and to date, adaptive immunity vaccine designs have had little to no success. Data indicate the alloimmune response is a potent mitigator of human immunodeficiency virus (HIV) infection, for which experiments of nature should be demonstrable to justify pursuit of an alloimmune vaccine strategy. We sought to determine if large-scale alloimmune diversity correlates with lower HIV infection rates.

The conserved set of host proteins incorporated into HIV-1 virions suggests a common egress pathway in multiple cell types.

HIV-1 incorporates a large array of host proteins into virions. Determining the host protein composition in HIV virions has technical difficulties, including copurification of microvesicles. We developed an alternative purification technique using cholesterol that differentially modulates the density of virions and microvesicles (density modification, DM) allowing for high-yield virion purification that is essential for tandem mass spectrometric and quantitative proteomic (iTRAQ) analysis.

Human immunodeficiency virus type 1 Vpu and cellular TASK proteins suppress transcription of unintegrated HIV-1 DNA.

Background: Unintegrated HIV-1 DNA serves as transcriptionally active templates in HIV-infected cells. Several host factors including NF-κβ enhance HIV-1 transcription. HIV-1 induced NF-κβ activation can be suppressed by viral protein U (Vpu).

Cholesterol depletion inactivates XMRV and leads to viral envelope protein release from virions: evidence for role of cholesterol in XMRV infection.

Membrane cholesterol plays an important role in replication of HIV-1 and other retroviruses. Here, we report that the gammaretrovirus XMRV requires cholesterol and lipid rafts for infection and replication. We demonstrate that treatment of XMRV with a low concentration (10 mM) of 2-hydroxypropyl-β-cyclodextrin (2OHpβCD) partially depleted virion-associated cholesterol resulting in complete inactivation of the virus.

Caveolin-1 suppresses human immunodeficiency virus-1 replication by inhibiting acetylation of NF-κB.

Caveolin-1 is an integral membrane protein primarily responsible for the formation of membrane structures known as caveolae. Caveolae are specialized lipid rafts involved in protein trafficking, cholesterol homeostasis, and a number of signaling functions. It has been demonstrated that caveolin-1 suppresses HIV-1 protein expression.

Antibody against integrin lymphocyte function-associated antigen 1 inhibits HIV type 1 infection in primary cells through caspase-8-mediated apoptosis.

HIV-1 infection induces formation of a virological synapse wherein CD4, chemokine receptors, and cell-adhesion molecules such as lymphocyte function-associated antigen 1 (LFA-1) form localized domains on the cell surface. Studies show that LFA-1 on the surface of HIV-1 particles retains its adhesion function and enhances virus attachment to susceptible cells by binding its counterreceptor intercellular adhesion molecule 1 (ICAM-1). This virus-cell interaction augments virus infectivity by facilitating binding and entry events.

Cultural differences in acceptability of a vaginal microbicide: a comparison between potential users from Nashville, Tennessee, USA, and Kafue and Mumbwa, Zambia.

Purpose: We sought to determine the relationship between acceptability of a hypothetical vaginal microbicide, cultural factors, and perceived HIV risk among African-American women in Nashville, TN, USA, and African women in Kafue and Mumbwa, Zambia.

Patients And Methods: Women in both sites completed a survey. Regression analyses were performed on valid samples (Nashville, 164; Zambia, 101) to determine cultural differences affecting microbicide acceptability.

Loss of Niemann Pick type C proteins 1 and 2 greatly enhances HIV infectivity and is associated with accumulation of HIV Gag and cholesterol in late endosomes/lysosomes.

Background: Cholesterol pathways play an important role at multiple stages during the HIV-1 infection cycle. Here, we investigated the role of cholesterol trafficking in HIV-1 replication utilizing Niemann-Pick Type C disease (NPCD) cells as a model system.

Results: We used a unique NPC2-deficient cell line (NPCD55) that exhibited Gag accumulation as well as decreased NPC1 expression after HIV infection.

Filamin A protein interacts with human immunodeficiency virus type 1 Gag protein and contributes to productive particle assembly.

HIV-1 Gag precursor directs virus particle assembly and release. In a search for Gag-interacting proteins that are involved in late stages of the HIV-1 replication cycle, we performed yeast two-hybrid screening against a human cDNA library and identified the non-muscle actin filament cross-linking protein filamin A as a novel Gag binding partner. The 280-kDa filamin A regulates cortical actin network dynamics and participates in the anchoring of membrane proteins to the actin cytoskeleton.

Sterol regulatory element-binding protein 2 couples HIV-1 transcription to cholesterol homeostasis and T cell activation.

Cholesterol plays an essential role in the life cycle of several enveloped viruses. Many of these viruses manipulate host cholesterol metabolism to facilitate their replication. HIV-1 infection of CD4(+) T cells activates the sterol regulatory element-binding protein 2 (SREBP2) transcriptional program, which includes genes involved in cholesterol homeostasis.

N-terminal hemagglutinin tag renders lysine-deficient APOBEC3G resistant to HIV-1 Vif-induced degradation by reduced polyubiquitination.

APOBEC3G, a potent HIV-1 host restriction factor, is overcome by HIV-1 viral infectivity factor (Vif), which induces its polyubiquitination and proteasomal degradation. Here we show that lysine-deficient APOBEC3G with an N-terminal hemagglutinin (HA) tag fusion (HA-A3G20K/R) was resistant to HIV-1 Vif-induced proteasomal degradation. HA-A3G20K/R molecules were packaged into wild-type HIV-1 particles, and HA-A3G20K/R drastically decreased wild-type HIV-1 reverse transcription products and infectivity.

Non-productive HIV-1 infection of human glomerular and urinary podocytes.

Podocyte damage induced by HIV-1 is critical to the pathogenesis of HIV-1 associated nephropathy (HIVAN) and is believed to result from productive replication of the virus. Here we demonstrate that HIV-1 readily enters human podocytes by a dynamin-mediated endocytosis but does not establish productive infection. We provide evidence suggesting that viral nucleic acids and proteins detected in podocytes are delivered by viral particles internalized by the cells.

Inhibition of LINE-1 and Alu retrotransposition by exosomes encapsidating APOBEC3G and APOBEC3F.

Human cytidine deaminases, including APOBEC3G (A3G) and A3F, are part of a cellular defense system against retroviruses and retroelements including non-LTR retrotransposons LINE-1 (L1) and Alu. Expression of cellular A3 proteins is sufficient for inhibition of L1 and Alu retrotransposition, but the effect of A3 proteins transferred in exosomes on retroelement mobilization is unknown. Here, we demonstrate for the first time that exosomes secreted by CD4(+)H9 T cells and mature monocyte-derived dendritic cells encapsidate A3G and A3F and inhibit L1 and Alu retrotransposition.

Polyubiquitination of APOBEC3G is essential for its degradation by HIV-1 Vif.

Proteasomal degradation of APOBEC3G is a critical step for human immunodeficiency virus type 1 (HIV-1) replication. However, the necessity for polyubiquitination of APOBEC3G in this process is still controversial. In this study, we showed that although macaque simian immunodeficiency virus (SIVmac) Vif is more stable than HIV-1 Vif in human cells, SIVmac Vif induces degradation of APBOEC3G as efficiently as HIV-1 Vif.

Deficiency of niemann-pick type C-1 protein impairs release of human immunodeficiency virus type 1 and results in Gag accumulation in late endosomal/lysosomal compartments.

Human immunodeficiency virus type 1 (HIV-1) relies on cholesterol-laden lipid raft membrane microdomains for entry into and egress out of susceptible cells. In the present study, we examine the need for intracellular cholesterol trafficking pathways with respect to HIV-1 biogenesis using Niemann-Pick type C-1 (NPC1)-deficient (NPCD) cells, wherein these pathways are severely compromised, causing massive accumulation of cholesterol in late endosomal/lysosomal (LE/L) compartments. We have found that induction of an NPC disease-like phenotype through treatment of various cell types with the commonly used hydrophobic amine drug U18666A resulted in profound suppression of HIV-1 release.

Exosomes packaging APOBEC3G confer human immunodeficiency virus resistance to recipient cells.

The human cytidine deaminase APOBEC3G (A3G) is a part of a cellular defense system against human immunodeficiency virus type 1 (HIV-1) and other retroviruses. Antiretroviral activity of A3G can be severely blunted in the presence of the HIV-1 protein Vif. However, in some cells expressing the enzymatically active low-molecular-mass form of A3G, HIV-1 replication is restricted at preintegration steps, before accumulation of Vif.

Incomplete protection against simian immunodeficiency virus vaginal transmission in rhesus macaques by a topical antiviral agent revealed by repeat challenges.

The rising prevalence of human immunodeficiency virus type 1 (HIV-1) infection in women, especially in resource-limited settings, accentuates the need for accessible, inexpensive, and female-controlled preexposure prophylaxis strategies to prevent mucosal transmission of the virus. While many compounds can inactivate HIV-1 in vitro, evaluation in animal models for mucosal transmission of virus may help identify which approaches will be effective in vivo. Macaques challenged intravaginally with pathogenic simian immunodeficiency virus (SIV(mac251)) provide a model to preclinically evaluate candidate microbicides.

Delipidated retroviruses as potential autologous therapeutic vaccines--a pilot experiment.

This pilot experiment in a simian immunodeficiency virus (SIV) chronic infection model aimed at extending our previous findings that vaccination with delipidated SIV resulted in more potent and diversified antiviral responses (1). Macaques chronically infected with SIVmac239 treated with antiretroviral therapy (ART) were vaccinated with autologous delipidated virus via consecutive lymph node targeted immunizations-1, 1 and 10 mug of virus spaced monthly. Results showed all animals had lasting viral load reduction approaching 1 log compared to set-point, and disease delay.

Cervicovaginal evaluation in macaques used as a model for topical microbicide safety studies.

Introduction: Macaques are a commonly used non-human primate (NHP) model to evaluate safety and efficacy of topically applied vaginal microbicides. Cervicovaginal evaluation for topical microbicide safety studies requires proper technique, equipment, supplies, and sequence of sample collection.

Materials And Methods: Eleven rhesus macaques received a comprehensive sequential cervicovaginal examination under sedation before treatment and 24 hours post-instillation of test material.

Production and characterization of a monoclonal antibody against Niemann Pick type C protein.

Niemann Pick type C is a severe, incurable disease caused, in the majority of cases, by mutations in the Niemann Pick type C protein 1 (NPC1). The pathology and biochemical changes associated with the disease have been extensively studied. However, the function of the protein is still unknown, and recent studies challenge the established concept that a defect in cholesterol and sphingolipids transport is the primary cause of this human lipidosis.

Exosomes and HIV Gag bud from endosome-like domains of the T cell plasma membrane.

Exosomes are secreted, single membrane organelles of approximately 100 nm diameter. Their biogenesis is typically thought to occur in a two-step process involving (1) outward vesicle budding at limiting membranes of endosomes (outward = away from the cytoplasm), which generates intralumenal vesicles, followed by (2) endosome-plasma membrane fusion, which releases these internal vesicles into the extracellular milieu as exosomes. In this study, we present evidence that certain cells, including Jurkat T cells, possess discrete domains of plasma membrane that are enriched for exosomal and endosomal proteins, retain the endosomal property of outward vesicle budding, and serve as sites of immediate exosome biogenesis.

Characterization of an anti-lymphocyte function-associated antigen-1 antibody in a simian immunodeficiency virus-pig-tailed macaque (Macaca nemestrina) model.

The simian immunodeficiency virus (SIV)/pig-tailed macaque (Macaca nemestrina) model of acquired immune deficiency syndrome (AIDS) is a powerful system in which to study cell adhesion molecules and retroviral pathogenesis in vivo. Preliminary experiments were conducted to examine the role of lymphocyte function-associated antigen 1 (LFA-1) in early SIV infection in vivo by using an LFA-1 monoclonal antibody (MHM.23) specific to human LFA-1.