Characterization of antiviral activity of benzamide derivative AH0109 against HIV-1 infection

Identification and evaluation of the inhibitory effect of Prunella vulgaris extract on SARS-coronavirus 2 virus entry

Until now, antiviral therapeutic agents are still urgently required for treatment or prevention of SARS-coronavirus 2 (SCoV-2) virus infection. In this study, we established a sensitive SCoV-2 Spike glycoprotein (SP), including an SP mutant D614G, pseudotyped HIV-1-based vector system and tested their ability to infect ACE2-expressing cells. Based on this system, we have demonstrated that an aqueous extract from the Natural herb Prunella vulgaris (NhPV) displayed potent inhibitory effects on SCoV-2 SP (including SPG614 mutant) pseudotyped virus (SCoV-2-SP-PVs) mediated infections. Moreover, we have compared NhPV with another compound, Suramin, for their anti-SARS-CoV-2 activities and the mode of their actions, and found that both NhPV and Suramin are able to directly interrupt SCoV-2-SP binding to its receptor ACE2 and block the viral entry step. Importantly, the inhibitory effects of NhPV and Suramin were confirmed by the wild type SARS-CoV-2 (hCoV-19/Canada/ON-VIDO-01/2020) virus infection in Vero cells. Furthermore, our results also demonstrated that the combination of NhPV/Suramin with an anti-SARS-CoV-2 neutralizing antibody mediated a more potent blocking effect against SCoV2-SP-PVs. Overall, by using SARS-CoV-2 SP-pseudotyped HIV-1-based entry system, we provide strong evidence that NhPV and Suramin have anti-SARS-CoV-2 activity and may be developed as a novel antiviral approach against SARS-CoV-2 infection.

Rhizobial-metabolite based biocontrol of fusarium wilt in pigeon pea

The application of rhizobial cells for improving pigeon pea fitness has been practiced for ages. As cell-based approaches have limitations, the focus is on the usage of cell-free formulations. In the present study exopolysaccharide (EPS) producing, plant health promoting Bradyrhizobium sp. IC-4059 was monitored for its biocontrol potential against Fusarium udum. Strain IC-4059, its EPS, and supernatant antagonized F.udum by 52.6%, 20.5%, and 48.1%, respectively in comparison to control. Diverse formulations prepared using EPS, supernatant, and cells of strain IC-4059 were: EPS based, supernatant based, IC-4059 liquid culture (rhizobia based), dual combination (IC-4059 cells + supernatant; IC-4059 cells + EPS; EPS + supernatant), and triple combination (IC-4059 cells + supernatant + EPS). The potency of these bioformulations was observed under in planta tubes followed by in vivo pot study, both in F.udum infested and non-infested sets taking pigeon pea cultivar UPAS-120 as a model crop. The study highlighted that seeds receiving triple combination exhibited significantly higher plant growth attributes, nodule enhancing, and disease suppressing activity in comparison to individual application of Bradyrhizobium. Antifungal compounds were analyzed by a metabolomic approach using UPLC-MS. Thus, the study disseminates the tripartite role of triple formulation as a plant growth stimulator, nodule enhancer, and disease suppressor, both under in vitro and in vivo conditions in the presence of phytopathogen F. udum.

Activation of HIV-1 expression in latently infected CD4+ T cells by the small molecule PKC412

Background

HIV-1 latency is a major obstacle for HIV-1 eradication. Extensive efforts are being directed toward the reactivation of latent HIV reservoirs with the aim of eliminating latently infected cells via the host immune system and/or virus-mediated cell lysis.

Results

We screened over 1,500 small molecules and kinase inhibitors and found that a small molecule, PKC412 (midostaurin, a broad-spectrum kinase inhibitor), can stimulate viral transcription and expression from the HIV-1 latently infected ACH2 cell line and primary resting CD4+ T cells. PKC412 reactivated HIV-1 expression in ACH2 cells in a dose- and time-dependent manner. Our results also suggest that the nuclear factor κB (NF-κB) signaling could be one of cellular pathways activated during PKC412-mediated activation of latent HIV-1 expression. Additionally, combining PKC412 with the HDAC inhibitor vorinostat (VOR) had an additive effect on HIV-1 reactivation in both ACH2 cells and infected resting CD4+ T cells.

Conclusions

These studies provide evidence that PKC412 is a new compound with the potential for optimization as a latency-reactivator to eradicate HIV-1 infection.

Anti-Inflammation of N-Benzyl-4-Bromobenzamide in Lipopolysaccharide-Induced Human Gingival Fibroblasts

OBJECTIVE

To evaluate the effect of N-benzyl-4-bromobenzamide (NBBA) on lipopolysaccharide (LPS)-induced IL-6 and prostaglandin E2 (PGE2) production in human gingival fibroblasts (HGFs).

MATERIAL AND METHODS

The benzamide compound was synthesized. The condition for IL-6 production of HGFs after induction with LPS was optimized. The HGFs were incubated with NBBA (10 µg/ml) for 30 min before LPS (1 μg/ml) was added. After 24 h of incubation time, the culture media were harvested and their IL-6 and PGE2 contents were determined using an enzyme-linked immunosorbent assay. Prednisolone (PDS) and NS-398 were used as positive controls. Statistical analysis of the IL-6 and PGE2 contents was performed using the ANOVA test followed by the Tukey multiple-comparisons test to compare replicate means. p < 0.001 was considered statistically significant.

RESULTS

The maximum IL-6 production was achieved when HGFs were exposed to 1 μg/ml of LPS for 24 h, which was inhibited by the IL-6 immunosuppressant PDS. The benzamide compound, NBBA, exhibited a potent anti-IL-6 activity with inhibition of 35.6 ± 0.5%, significantly different from in the LPS-induced HGFs (p < 0.001). In addition, it inhibited 75.6 ± 0.52% PGE2 production. Cell viability was not significantly affected by treatment with NBBA at a concentration <10 µg/ml (p < 0.001).

CONCLUSIONS

NBBA exhibited an inhibitory effect on the production of IL-6 and PGE2 in LPS-induced HGFs. It could serve as a compound with inhibiting inflammatory activity in periodontal disease.

Identification and characterization of a new type of inhibitor against the human immunodeficiency virus type-1 nucleocapsid protein

Background

The human immunodeficiency virus type-1 (HIV-1) nucleocapsid protein (NC) is an essential and multifunctional protein involved in multiple stages of the viral life cycle such as reverse transcription, integration of proviral DNA, and especially genome RNA packaging. For this reason, it has been considered as an attractive target for the development of new anti-HIV drugs. Although a number of inhibitors of NC have been reported thus far, the search for NC-specific and functional inhibitor(s) with a good antiviral activity continues.

Results

In this study, we report the identification of A1752, a small molecule with inhibitory action against HIV-1 NC, which shows a strong antiviral efficacy and an IC₅₀ around 1 μM. A1752 binds directly to HIV-1 NC, thereby inhibiting specific chaperone functions of NC including Psi RNA dimerization and complementary trans-activation response element (cTAR) DNA destabilization, and it also disrupts the proper Gag processing. Further analysis of the mechanisms of action of A1752 also showed that it generates noninfectious viral particles with defects in uncoating and reverse transcription in the infected cells.

Conclusions

These results demonstrate that A1752 is a specific and functional inhibitor of NC with a novel mode of action and good antiviral efficacy. Thus, this agent provides a new type of anti-HIV NC inhibitor candidate for further drug development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12977-015-0218-9) contains supplementary material, which is available to authorized users.