The nerve growth factor reduces APOBEC3G synthesis and enhances HIV-1 transcription and replication in human primary macrophages.

Macrophages infected with HIV-1 sustain viral replication for long periods of time, functioning as viral reservoirs. Therefore, recognition of factors that maintain macrophage survival and influence HIV-1 replication is critical to understanding the mechanisms that regulate the HIV-1-replicative cycle. Because HIV-1-infected macrophages release the nerve growth factor (NGF), and NGF neutralization reduces viral production, we further analyzed how this molecule affects HIV-1 replication. In the present study, we show that NGF stimulates HIV-1 replication in primary macrophages by signaling through its high-affinity receptor Tropomyosin-related Kinase A (TrKA), and with the involvement of reticular calcium, protein kinase C, extracellular signal-regulated kinase, p38 kinase, and nuclear factor-κB. NGF-induced enhancement of HIV-1 replication occurred during the late events of the HIV-1-replicative cycle, with a concomitant increase in viral transcription and production. In addition, NGF reduced the synthesis of the cellular HIV-1 restriction factor APOBEC3G and also overrode its interferon-γ-induced up-regulation, allowing the production of a well-fitted virus. Because NGF-TrKA signaling is a crucial event for macrophage survival, it is possible that NGF-induced HIV-1 replication plays a role in the maintenance of HIV-1 reservoirs. Our study may contribute to the understanding of the immunopathogenesis of HIV-1 infection and provide insights about approaches aimed at limiting viral replication in HIV-1 reservoirs.

Characterization of HIV-1 enzyme reverse transcriptase inhibition by the compound 6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl) quinoline-3-carboxylic acid through kinetic and in silico studies.

We recently described that the chloroxoquinolinic ribonucleoside 6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl) quinoline-3-carboxylic acid (compound A) inhibits the human immunodeficiency virus type 1 (HIV-1) enzyme reverse transcriptase (RT), and its replication in primary cells. Based on these findings, we performed kinetic studies to investigate the mode of inhibition of compound A and its aglycan analog (compound B). We found that both molecules inhibited RT activity independently of the template/primer used. Nevertheless, compound A was 10-fold more potent than compound B. Compound A inhibited the RNA-dependent DNA polymerase (RDDP) activity of RT with an uncompetitive and a noncompetitive mode of action with respect to dTTP incorporation and to template/primer (TP) uptake, respectively. The kinetic pattern of the inhibition displayed by compound A was probably due to its greater affinity for the ternary complex (RT-TP-dNTP) than the enzyme alone or the binary complex (RT-TP). Besides, by means of molecular modeling, we show that compound A bound on the NNRTI binding pocket of RT. However, our molecule targets such a site by making novel interactions with the enzyme RT, when compared to NNRTIs. These include a hydrogen bridge between the 2'-OH of our compound and the Tyr675 of the enzyme RT's chain B. Therefore, compound A is able to synergize with both a NRTI (AZT-TP) and a NNRTI (efavirenz). Taken together, our results suggest that compound A displays a novel mechanism of action, which may be different from classical NRTIs and NNRTIs.

Synthesis, HIV-RT inhibitory activity and SAR of 1-benzyl-1H-1,2,3-triazole derivatives of carbohydrates.

This paper describes the synthesis of several 1-benzyl-1H-1,2,3-triazoles attached to different carbohydrate templates and their in vitro inhibitory profile against HIV-1 reverse transcriptase. In addition a theoretical comparison of the most active compounds with other classical antivirals was also performed. Our results showed 2a, 2d and 2g as the most active compounds that inhibited the HIV-1 reverse transcriptase catalytic activity with cytotoxicity lower than AZT and SI higher than DDC and DDI. The overall theoretical analysis of the molecular descriptors of 2a, 2d and 2g revealed that their HOMO energy is similar to other antivirals in use (AZT, DDC, DDI and 3TC) and together with the volume may contribute for the biological profile as they may allow new interactions with the target. In fact the 1,2,3-triazole compounds presented more lipophilicity and higher molecular volume and weight than the antivirals studied, which suggested that these features might not only contribute for new interactions with the HIV-RT but also influence the specificity and consequently the low cytoxicity profile of these compounds. Thus these data point them as promising leading compounds for generating new anti-HIV-RT compounds.

The compound 6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl) quinoline-3-carboxylic acid inhibits HIV-1 replication by targeting the enzyme reverse transcriptase.

We describe in this paper that the chloroxoquinolinic ribonucleoside 6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl)-quinoline-3-carboxylic acid (compound A) inhibits the HIV-1 replication in human primary cells. We initially observed that compound A inhibited HIV-1 infection in peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner, resulting in an EC(50) of 1.5 +/- 0.5 microM and in a selective index of 1134. Likewise, compound A blocked HIV-1(BA-L) replication in macrophages in a dose-dependent manner, with an EC(50) equal to 4.98 +/- 0.9 microM. The replication of HIV-1 isolates from subtypes C and F was also inhibited by compound A with the same efficiency. Compound A inhibited an early event of the HIV-1 replicative cycle, since it prevented viral DNA synthesis in PBMCs exposed to HIV-1. Kinetic assays demonstrated that compound A inhibits the HIV-1 enzyme reverse transcriptase (RT) in dose-dependent manner, with a K(I) equal to 0.5 +/- 0.04 microM. Using a panel of HIV-1 isolates harboring NNRTI resistance mutations, we found a low degree of cross-resistance between compound A and clinical available NNRTIs. In addition, compound A exhibited additive effects with the RT inhibitors AZT and nevirapine, and synergized with the protease inhibitor atazanavir. Our results encourage continuous studies about the kinetic impact of compound A towards different catalytic forms of RT enzyme, and suggest that our nucleoside represents a promising molecule for future antiretroviral drug design.