Cellulose acetate phthalate, a common pharmaceutical excipient, inactivates HIV-1 and blocks the coreceptor binding site on the virus envelope glycoprotein gp120

BACKGROUND: Cellulose acetate phthalate (CAP), a pharmaceutical excipient used for enteric film coating of capsules and tablets, was shown to inhibit infection by the human immunodeficiency virus type 1 (HIV-1) and several herpesviruses. CAP formulations inactivated HIV-1, herpesvirus types 1 (HSV-1) and 2 (HSV-2) and the major nonviral sexually transmitted disease (STD) pathogens and were effective in animal models for vaginal infection by HSV-2 and simian immunodeficiency virus. METHODS: Enzyme-linked immunoassays and flow cytometry were used to demonstrate CAP binding to HIV-1 and to define the binding site on the virus envelope. RESULTS: 1) CAP binds to HIV-1 virus particles and to the envelope glycoprotein gp120; 2) this leads to blockade of the gp120 V3 loop and other gp120 sites resulting in diminished reactivity with HIV-1 coreceptors CXCR4 and CCR5; 3) CAP binding to HIV-1 virions impairs their infectivity; 4) these findings apply to both HIV-1 IIIB, an X4 virus, and HIV-1 BaL, an R5 virus. CONCLUSIONS: These results provide support for consideration of CAP as a topical microbicide of choice for prevention of STDs, including HIV-1 infection

Efficacy, Stability, and Biosafety of Sifuvirtide Gel as a Microbicide Candidate against HIV-1

Sifuvirtide is a proven effective HIV-1 entry inhibitor and its safety profile has been established for systemic administration. The present study evaluated the potential of sifuvirtide formulated in a universal gel for topical use as a microbicide candidate for preventing sexual transmission of HIV. Our data showed that sifuvirtide formulated in HEC gel is effective against HIV-1 B, C subtypes, CRF07_BC and CRF01_AE, the latter two recombinants represents the most prevalent strains in China. In addition, we demonstrated that sifuvirtide in gel is stable for at least 8 weeks even at 40°C, and did not cause the disruption of integrity of mucosal epithelial surface, or the up-regulation of inflammatory cytokines both in vitro or in vivo. These results suggest that sifuvirtide gel is an effective, safe and stable product, and should be further tested as a vaginal or rectal microbicide in pre-clinical model or clinical trial for preventing HIV sexual transmission

Improving Coping Skills for Self-management of Treatment Side Effects Can Reduce Antiretroviral Medication Nonadherence among People Living with HIV

BackgroundHuman immunodeficiency virus (HIV) treatment side effects have a deleterious impact on treatment adherence, which is necessary to optimize treatment outcomes including morbidity and mortality.PurposeTo examine the effect of the Balance Project intervention, a five-session, individually delivered HIV treatment side effects coping skills intervention on antiretroviral medication adherence.MethodsHIV+ men and women (N = 249) on antiretroviral therapy (ART) with self-reported high levels of ART side effect distress were randomized to intervention or treatment as usual. The primary outcome was self-reported ART adherence as measured by a combined 3-day and 30-day adherence assessment.ResultsIntent-to-treat analyses revealed a significant difference in rates of nonadherence between intervention and control participants across the follow-up time points such that those in the intervention condition were less likely to report nonadherence. Secondary analyses revealed that intervention participants were more likely to seek information about side effects and social support in efforts to cope with side effects.ConclusionsInterventions focusing on skills related to ART side-effects management show promise for improving ART adherence among persons experiencing high levels of perceived ART side effects

The SR-BI Partner PDZK1 Facilitates Hepatitis C Virus Entry

Entry of hepatitis C virus (HCV) into hepatocytes is a multi-step process that involves a number of different host cell factors. Following initial engagement with glycosaminoglycans and the low-density lipoprotein receptor, it is thought that HCV entry proceeds via interactions with the tetraspanin CD81, scavenger receptor class B type I (SR-BI), and the tight-junction proteins claudin-1 (CLDN1) and occludin (OCLN), culminating in clathrin-dependent endocytosis of HCV particles and their pH-dependent fusion with endosomal membranes. Physiologically, SR-BI is the major receptor for high-density lipoproteins (HDL) in the liver, where its expression is primarily controlled at the post-transcriptional level by its interaction with the scaffold protein PDZK1. However, the importance of interaction with PDZK1 to the involvement of SR-BI in HCV entry is unclear. Here we demonstrate that stable shRNA-knockdown of PDZK1 expression in human hepatoma cells significantly reduces their susceptibility to HCV infection, and that this effect can be reversed by overexpression of full length PDZK1 but not the first PDZ domain of PDZK1 alone. Furthermore, we found that overexpression of a green fluorescent protein chimera of the cytoplasmic carboxy-terminus of SR-BI (amino acids 479–509) in Huh-7 cells resulted in its interaction with PDZK1 and a reduced susceptibility to HCV infection. In contrast a similar chimera lacking the final amino acid of SR-BI (amino acids 479–508) failed to interact with PDZK1 and did not inhibit HCV infection. Taken together these results indicate an indirect involvement of PDZK1 in HCV entry via its ability to interact with SR-BI and enhance its activity as an HCV entry factor

Complementation of diverse HIV-1 Env defects through cooperative subunit interactions: a general property of the functional trimer

<p>Abstract</p> <p>Background</p> <p>The HIV-1 Env glycoprotein mediates virus entry by catalyzing direct fusion between the virion membrane and the target cell plasma membrane. Env is composed of two subunits: gp120, which binds to CD4 and the coreceptor, and gp41, which is triggered upon coreceptor binding to promote the membrane fusion reaction. Env on the surface of infected cells is a trimer consisting of three gp120/gp41 homo-dimeric protomers. An emerging question concerns cooperative interactions between the protomers in the trimer, and possible implications for Env function.</p> <p>Results</p> <p>We extended studies on cooperative subunit interactions within the HIV-1 Env trimer, using analysis of functional complementation between coexpressed inactive variants harboring different functional deficiencies. In assays of Env-mediated cell fusion, complementation was observed between variants with a wide range of defects in both the gp120 and gp41 subunits. The former included gp120 subunits mutated in the CD4 binding site or incapable of coreceptor interaction due either to mismatched specificity or V3 loop mutation. Defective gp41 variants included point mutations at different residues within the fusion peptide or heptad repeat regions, as well as constructs with modifications or deletions of the membrane proximal tryptophan-rich region or the transmembrane domain. Complementation required the defective variants to be coexpressed in the same cell. The observed complementation activities were highly dependent on the assay system. The most robust activities were obtained with a vaccinia virus-based expression and reporter gene activation assay for cell fusion. In an alternative system involving Env expression from integrated provirus, complementation was detected in cell fusion assays, but not in virus particle entry assays.</p> <p>Conclusion</p> <p>Our results indicate that Env function does not require every subunit in the trimer to be competent for all essential activities. Through cross-talk between subunits, the functional determinants on one defective protomer can cooperatively interact to trigger the functional determinants on an adjacent protomer(s) harboring a different defect, leading to fusion. Cooperative subunit interaction is a general feature of the Env trimer, based on complementation activities observed for a highly diverse range of functional defects.</p

Engineering HIV-Resistant Human CD4+ T Cells with CXCR4-Specific Zinc-Finger Nucleases

HIV-1 entry requires the cell surface expression of CD4 and either the CCR5 or CXCR4 coreceptors on host cells. Individuals homozygous for the ccr5Δ32 polymorphism do not express CCR5 and are protected from infection by CCR5-tropic (R5) virus strains. As an approach to inactivating CCR5, we introduced CCR5-specific zinc-finger nucleases into human CD4+ T cells prior to adoptive transfer, but the need to protect cells from virus strains that use CXCR4 (X4) in place of or in addition to CCR5 (R5X4) remains. Here we describe engineering a pair of zinc finger nucleases that, when introduced into human T cells, efficiently disrupt cxcr4 by cleavage and error-prone non-homologous DNA end-joining. The resulting cells proliferated normally and were resistant to infection by X4-tropic HIV-1 strains. CXCR4 could also be inactivated in ccr5Δ32 CD4+ T cells, and we show that such cells were resistant to all strains of HIV-1 tested. Loss of CXCR4 also provided protection from X4 HIV-1 in a humanized mouse model, though this protection was lost over time due to the emergence of R5-tropic viral mutants. These data suggest that CXCR4-specific ZFNs may prove useful in establishing resistance to CXCR4-tropic HIV for autologous transplant in HIV-infected individuals

Social, Structural and Behavioral Determinants of Overall Health Status in a Cohort of Homeless and Unstably Housed HIV-Infected Men

Background: Previous studies indicate multiple influences on the overall health of HIV-infected persons; however, few assess and rank longitudinal changes in social and structural barriers that are disproportionately found in impoverished populations. We empirically ranked factors that longitudinally impact the overall health status of HIV-infected homeless and unstably housed men. Methods and Findings: Between 2002 and 2008, a cohort of 288 HIV+ homeless and unstably housed men was recruited and followed over time. The population was 60 % non-Caucasian and the median age was 41 years; 67 % of study participants reported recent drug use and 20 % reported recent homelessness. At baseline, the median CD4 cell count was 349 cells/ml and 18 % of eligible persons (CD4,350) took antiretroviral therapy (ART). Marginal structural models were used to estimate the population-level effects of behavioral, social, and structural factors on overall physical and mental health status (measured by the SF-36), and targeted variable importance (tVIM) was used to empirically rank factors by their influence. After adjusting for confounding, and in order of their influence, the three factors with the strongest negative effects on physical health were unmet subsistence needs, Caucasian race, and no reported source of instrumental support. The three factors with the strongest negative effects on mental health were unmet subsistence needs, not having a close friend/confidant, and drug use. ART adherence.90 % ranked 5th for its positive influence on mental health, and viral loa

Expression of the chemokine receptor CCR5 in psoriasis and results of a randomized placebo controlled trial with a CCR5 inhibitor

Several reports have indicated that the chemokine receptor CCR5 and its ligands, especially CCL5 (formerly known as RANTES), may play a role in the pathogenesis of psoriasis. The purpose of this investigation was to examine the expression of CCR5 and its ligands in chronic plaque psoriasis and to evaluate the clinical and immunohistochemical effect of a CCR5 receptor inhibitor. Immunohistochemical analysis showed low but significant increased total numbers of CCR5 positive cells in epidermis and dermis of lesional skin in comparison to non-lesional skin. However, relative expression of CCR5 proportional to the cells observed revealed that the difference between lesional and non-lesional skin was only statistically significant in the epidermis for CD3 positive cells and in the dermis for CD68 positive cells. Quantification of mRNA by reverse transcriptase-polymerase chain reaction only showed an increased expression of CCL5 (RANTES) in lesional skin. A randomized placebo-controlled clinical trial in 32 psoriasis patients revealed no significant clinical effect and no changes at the immunohistochemical level comparing patients treated with placebo or a CCR5 inhibitor SCH351125. We conclude that although CCR5 expression is increased in psoriatic lesions, this receptor does not play a crucial role in the pathogenesis of psoriasis

CD4-Specific Designed Ankyrin Repeat Proteins Are Novel Potent HIV Entry Inhibitors with Unique Characteristics

Here, we describe the generation of a novel type of HIV entry inhibitor using the recently developed Designed Ankyrin Repeat Protein (DARPin) technology. DARPin proteins specific for human CD4 were selected from a DARPin DNA library using ribosome display. Selected pool members interacted specifically with CD4 and competed with gp120 for binding to CD4. DARPin proteins derived in the initial selection series inhibited HIV in a dose-dependent manner, but showed a relatively high variability in their capacity to block replication of patient isolates on primary CD4 T cells. In consequence, a second series of CD4-specific DARPins with improved affinity for CD4 was generated. These 2nd series DARPins potently inhibit infection of genetically divergent (subtype B and C) HIV isolates in the low nanomolar range, independent of coreceptor usage. Importantly, the actions of the CD4 binding DARPins were highly specific: no effect on cell viability or activation, CD4 memory cell function, or interference with CD4-independent virus entry was observed. These novel CD4 targeting molecules described here combine the unique characteristics of DARPins—high physical stability, specificity and low production costs—with the capacity to potently block HIV entry, rendering them promising candidates for microbicide development