74 research outputs found

    cAMP Signaling Enhances HIV-1 Long Terminal Repeat (LTR)-directed Transcription and Viral Replication in Bone Marrow Progenitor Cells.

    Get PDF
    CD34+ hematopoietic progenitor cells have been shown to be susceptible to HIV-1 infection, possibly due to a low-level expression of CXCR4, a coreceptor for HIV-1 entry. Given these observations, we have explored the impact of forskolin on cell surface expression of CXCR4 in a cell line model (TF-1). The elevation of intracellular cyclic adenosine monophosphate (cAMP) by forskolin through adenylyl cyclase (AC) resulted in transcriptional upregulation of CXCR4 with a concomitant increase in replication of the CXCR4-utilizing HIV-1 strain IIIB. Transient expression analyses also demonstrated an increase in CXCR4-, CCR5-, and CXCR4-/CCR5-utilizing HIV-1 (LAI, YU2, and 89.6, respectively) promoter activity. Studies also implicated the protein kinase A (PKA) pathway and the downstream transcription factor CREB-1 in interfacing with cAMP response elements located in the CXCR4 and viral promoter. These observations suggest that the cAMP signaling pathway may serve as a regulator of CXCR4 levels and concomitantly of HIV-1 replication in bone marrow (BM) progenitor cells. © 2017, © The Author(s) 2017

    A Styrene-alt-Maleic Acid Copolymer Is an Effective Inhibitor of R5 and X4 Human Immunodeficiency Virus Type 1 Infection

    Get PDF
    An alternating copolymer of styrene and maleic acid (alt-PSMA) differs from other polyanionic antiviral agents in that the negative charges of alt-PSMA are provided by carboxylic acid groups instead of sulfate or sulfonate moieties. We hypothesized that alt-PSMA would have activity against human immunodeficiency virus type 1 (HIV-1) comparable to other polyanions, such as the related compound, poly(sodium 4-styrene sulfonate) (PSS). In assays using cell lines and primary immune cells, alt-PSMA was characterized by low cytotoxicity and effective inhibition of infection by HIV-1 BaL and IIIB as well as clinical isolates of subtypes A, B, and C. In mechanism of action assays, in which each compound was added to cells and subsequently removed prior to HIV-1 infection (“washout” assay), alt-PSMA caused no enhancement of infection, while PSS washout increased infection 70% above control levels. These studies demonstrate that alt-PSMA is an effective HIV-1 inhibitor with properties that warrant further investigation

    Cervicovaginal Safety of the Formulated, Biguanide-Based Human Immunodeficiency Virus Type 1 (HIV-1) Inhibitor NB325 in a Murine Model

    Get PDF
    Vaginal microbicides that reduce or eliminate the risk of HIV-1 sexual transmission must do so safely without adversely affecting the integrity of the cervicovaginal epithelium. The present studies were performed to assess the safety of the biguanide-based antiviral compound NB325 in a formulation suitable for topical application. Experiments were performed using a mouse model of cervicovaginal microbicide application, which was previously shown to be predictive of topical agent toxicity revealed in microbicide clinical trials. Mice were exposed vaginally to unformulated NB325 or NB325 formulated in the hydroxyethyl cellulose “universal placebo.” Following exposures to formulated 1% NB325 for 10 min to 24 h, the vaginal and cervical epithelia were generally intact, although some areas of minimal vaginal epithelial damage were noted. Although formulated NB325 appeared generally safe for application in these studies, the low but observable level of toxicity suggests the need for improvements in the compound and/or formulation

    Utilization of HIV-1 envelope V3 to identify X4- and R5-specific Tat and LTR sequence signatures.

    Get PDF
    BACKGROUND: HIV-1 entry is a receptor-mediated process directed by the interaction of the viral envelope with the host cell CD4 molecule and one of two co-receptors, CCR5 or CXCR4. The amino acid sequence of the third variable (V3) loop of the HIV-1 envelope is highly predictive of co-receptor utilization preference during entry, and machine learning predictive algorithms have been developed to characterize sequences as CCR5-utilizing (R5) or CXCR4-utilizing (X4). It was hypothesized that while the V3 loop is predominantly responsible for determining co-receptor binding, additional components of the HIV-1 genome may contribute to overall viral tropism and display sequence signatures associated with co-receptor utilization. RESULTS: The accessory protein Tat and the HlV-1 long terminal repeat (LTR) were analyzed with respect to genetic diversity and compared by Jensen-Shannon divergence which resulted in a correlation with both mean genetic diversity as well as the absolute difference in genetic diversity between R5- and X4-genome specific trends. As expected, the V3 domain of the gp120 protein was enriched with statistically divergent positions. Statistically divergent positions were also identified in Tat amino acid sequences within the transactivation and TAR-binding domains, and in nucleotide positions throughout the LTR. We further analyzed LTR sequences for putative transcription factor binding sites using the JASPAR transcription factor binding profile database and found several putative differences in transcription factor binding sites between R5 and X4 HIV-1 genomes, specifically identifying the C/EBP sites I and II, and Sp site III to differ with respect to sequence configuration for R5 and X4 LTRs. CONCLUSION: These observations support the hypothesis that co-receptor utilization coincides with specific genetic signatures in HIV-1 Tat and the LTR, likely due to differing transcriptional regulatory mechanisms and selective pressures applied within specific cellular targets during the course of productive HIV-1 infection

    Non-Thermal Plasma-Induced Immunogenic Cell Death in Cancer: A Topical Review.

    Get PDF
    Recent advances in biomedical research in cancer immunotherapy have identified the use of an oxidative stress-based approach to treat cancers, which works by inducing immunogenic cell death (ICD) in cancer cells. Since the anti-cancer effects of non-thermal plasma (NTP) are largely attributed to the reactive oxygen and nitrogen species that are delivered to and generated inside the target cancer cells, it is reasonable to postulate that NTP would be an effective modality for ICD induction. NTP treatment of tumors has been shown to destroy cancer cells rapidly and, under specific treatment regimens, this leads to systemic tumor-specific immunity. The translational benefit of NTP for treatment of cancer relies on its ability to enhance the interactions between NTP-exposed tumor cells and local immune cells which initiates subsequent protective immune responses. This review discusses results from recent investigations of NTP application to induce immunogenic cell death in cancer cells. With further optimization of clinical devices and treatment protocols, NTP can become an essential part of the therapeutic armament against cancer
    corecore