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In people living with HIV (PLWH) on antiretroviral therapy (ART), virus persists in a latent form where there is minimal transcription or protein expression. Latently infected cells are a major barrier to curing HIV. Increasing HIV transcription and viral production in latently infected cells could facilitate immune recognition and reduce the pool of infected cells that persist on ART. Given that programmed cell death protein 1 (PD-1) expressing CD4+ T cells are preferentially infected with HIV in PLWH on ART, we aimed to determine whether administration of antibodies targeting PD-1 would reverse HIV latency in vivo. We therefore evaluated the impact of intravenous administration of pembrolizumab every 3 weeks on HIV latency in 32 PLWH and cancer on ART. After the first infusion of anti-PD-1, we observed a median 1.32-fold increase in unspliced HIV RNA and 1.61-fold increase in unspliced RNA:DNA ratio in sorted blood CD4+ T cells compared to baseline. We also observed a 1.65-fold increase in plasma HIV RNA. The frequency of CD4+ T cells with inducible virus evaluated using the tat/rev limiting dilution assay was higher after 6 cycles compared to baseline. Phylogenetic analyses of HIV env sequences in a participant who developed low concentrations of HIV viremia after 6 cycles of pembrolizumab did not demonstrate clonal expansion of HIV-infected cells. These data are consistent with anti-PD-1 being able to reverse HIV latency in vivo and support the rationale for combining anti-PD-1 with other interventions to reduce the HIV reservoir.

PurposeAIDS-related Kaposi sarcoma is often incompletely controlled, requiring serial therapies. Kaposi sarcoma herpesvirus (KSHV) induces transformation of endothelial cells, where it resides in a predominately latent state. We hypothesized proteasome inhibition would have direct antitumor activity, induce lytic activation of KSHV, and inhibit HIV infectivity, improving control of both Kaposi sarcoma and HIV. The primary objective was determining the MTD of bortezomib in AIDS-Kaposi sarcoma. Secondary objectives included estimating the impact of bortezomib on Kaposi sarcoma response, KSHV plasma DNA copy number (PDCN), and HIV viral loads (VL).Patients and methodsA 3+3 dose escalation design was employed evaluating four dose levels of bortezomib (0.75, 1, 1.2, or 1.6 mg/m2) administered intravenously on days 1, 8, and 15 of 28-day cycles in patients with relapsed/refractory (r/r) AIDS-Kaposi sarcoma taking antiretroviral therapy.ResultsSeventeen patients enrolled. No dose-limiting toxicities occurred and the MTD was not reached. The most common adverse events included diarrhea, fatigue and nausea. Among 15 evaluable patients, partial response (PR) occurred in nine (60%), with a PR rate of 83% in the 1.6 mg/m2 cohort; the remainder had stable disease (SD). Median time to response was 2.1 months. Median change in KSHV PDCN was significantly different between those with PR versus SD. During cycle 1, seven of 11 evaluable patients had decreases in HIV VL.ConclusionsBortezomib is well-tolerated and active in AIDS-Kaposi sarcoma. The 60% PR rate is notable given the dose-finding nature of the study in a r/r population. Changes in KSHV PDCN and HIV VL trended as hypothesized.

Disulfiram (DSF) was well tolerated and activated viral transcription (cell-associated unspliced (CA-US) and plasma human immunodeficiency virus (HIV) RNA) in a phase II dose-escalation trial in HIV+ antiretroviral therapy (ART)-suppressed participants. Here, we investigated whether exposure to DSF and its metabolites predicted these changes in HIV transcription. Participants were administered 500 (N = 10), 1,000 (N = 10), or 2,000 (N = 10) mg of DSF for 3 consecutive days. DSF and four metabolites were measured by ultraperformance liquid chromatography-tandem mass spectrometry. Changes in CA-US and plasma HIV RNA were quantified by polymerase chain reaction (PCR) and analyzed in NONMEM. A seven-compartment pharmacokinetic (PK) model demonstrated nonlinear elimination kinetics. The fitted median area under the curve values for 72 hours (AUC0-72 ) were 3,816, 8,386, and 22,331 mg*hour/L, respectively. Higher exposure predicted greater increases in CA-US (maximum effect (Emax ) = 78%, AUC50  = 1,600 μg*hour/L, P = 0.013) but not plasma HIV RNA. These results provide support for further development of DSF as an important drug for future HIV cure strategies.

The HIV-1 nucleocapsid protein (NC) is a multifunctional viral protein necessary for HIV-1 replication. Recent studies have demonstrated that reverse transcription (RT) completes in the intact viral capsid, and the timing of RT and uncoating are correlated. How the small viral core stably contains the ~10 kbp double stranded (ds) DNA product of RT, and the role of NC in this process, are not well understood. We showed previously that NC binds and saturates dsDNA in a non-specific electrostatic binding mode that triggers uniform DNA self-attraction, condensing dsDNA into a tight globule against extending forces up to 10 pN. In this study, we use optical tweezers and atomic force microscopy to characterize the role of NC's basic residues in dsDNA condensation. Basic residue mutations of NC lead to defective interaction with the dsDNA substrate, with the constant force plateau condensation observed with wild-type (WT) NC missing or diminished. These results suggest that NC's high positive charge is essential to its dsDNA condensing activity, and electrostatic interactions involving NC's basic residues are responsible in large part for the conformation, size, and stability of the dsDNA-protein complex inside the viral core. We observe DNA re-solubilization and charge reversal in the presence of excess NC, consistent with the electrostatic nature of NC-induced DNA condensation. Previous studies of HIV-1 replication in the presence of the same cationic residue mutations in NC showed significant defects in both single- and multiple-round viral infectivity. Although NC participates in many stages of viral replication, our results are consistent with the hypothesis that cationic residue mutations inhibit genomic DNA condensation, resulting in increased premature capsid uncoating and contributing to viral replication defects. [ABSTRACT FROM AUTHOR]

BackgroundIn vitro, disulfiram activated HIV transcription in a primary T-cell model of HIV latency and in a pilot clinical study increased plasma HIV RNA in individuals with adequate drug exposure. We assessed the effect of disulfiram on HIV transcription in a dose-escalation study.MethodsIn this prospective dose-escalation study, to optimise disulfiram exposure we included adults with HIV on suppressive antiretroviral therapy, with plasma HIV RNA of less than 50 copies per mL and a CD4 cell count greater than 350 cells per μL. Participants were allocated sequentially to one of three dosing groups (500 mg, 1000 mg, and 2000 mg) and received disulfiram daily for 3 days. Only the staff who did laboratory assays were masked to group assignment. The primary endpoint was change in cell-associated unspliced HIV RNA in CD4 cells. The primary analysis method was a negative binomial regression, with the number of copies as the outcome variable and the input total RNA or plasma volume as an exposure variable, which is equivalent to modelling copies or input. We used these models to estimate changes from before disulfiram to timepoints during and after disulfiram administration. This study is registered with ClinicalTrials.gov, number NCT01944371.FindingsOf 34 participants screened for eligibility at The Alfred Hospital (Melbourne, VIC, Australia), and San Francisco General Hospital (San Francisco, CA, USA), 30 people were enrolled between Sept 24, 2013, and March 31, 2014. The estimated fold increases in cell-associated unspliced HIV RNA from baseline were 1·7 (95% CI 1·3-2·2; p

Single-stranded RNA viruses encompass broad classes of infectious agents and cause the common cold, cancer, AIDS and other serious health threats. Viral replication is regulated at many levels, including the use of conserved genomic RNA structures. Most potential regulatory elements in viral RNA genomes are uncharacterized. Here we report the structure of an entire HIV-1 genome at single nucleotide resolution using SHAPE, a high-throughput RNA analysis technology. The genome encodes protein structure at two levels. In addition to the correspondence between RNA and protein primary sequences, a correlation exists between high levels of RNA structure and sequences that encode inter-domain loops in HIV proteins. This correlation suggests that RNA structure modulates ribosome elongation to promote native protein folding. Some simple genome elements previously shown to be important, including the ribosomal gag-pol frameshift stem-loop, are components of larger RNA motifs. We also identify organizational principles for unstructured RNA regions, including splice site acceptors and hypervariable regions. These results emphasize that the HIV-1 genome and, potentially, many coding RNAs are punctuated by previously unrecognized regulatory motifs and that extensive RNA structure constitutes an important component of the genetic code., Genomes of all single-stranded RNA viruses contain internal structures fundamental to viral replication and host defence evasion. Important viral RNA structures include internal ribosome entry sites, packaging signals, pseudoknots, transfer [...]

The nucleocapsid protein of HIV-1 is 55 amino acids in lengths and possesses two CCHC-type zinc fingers where finger one (N-terminal) contributes significantly more to helix destabilizing activity than finger two (C-terminal). Study is presented in an attempt to determine at the amino acid level the reason for the apparent distinction between the zinc fingers. Results indicate that amino acid differences at positions 24 and 27 contribute significantly to finger one's helix destabilizing activity.

We tested the combination of a broadly neutralizing HIV antibody with the latency reversal agent vorinostat (VOR). Eight participants received 2 month-long cycles of VRC07-523LS with VOR. Low-level viremia, resting CD4+ T-cell-associated HIV RNA (rca-RNA) was measured, and intact proviral DNA assay (IPDA) and quantitative viral outgrowth assay (QVOA) were performed at baseline and posttreatment. In 3 participants, IPDA and QVOA declines were accompanied by significant declines of rca-RNA. However, no IPDA or QVOA declines clearly exceeded assay variance or natural decay. Increased resistance to VRC07-523LS was not observed. This combination therapy did not reduce viremia or the HIV reservoir. Clinical Trials Registration. NCT03803605. [ABSTRACT FROM AUTHOR]