Poly (4-styrenesulfonic acid-co-maleic acid) is an entry inhibitor against both HIV-1 and HSV infections - potential as a dual functional microbicide

Can a metabolism-targeted therapeutic intervention successfully subjugate SARS-COV-2? A scientific rational

As a process entailing a high turnover of the host cell molecules, viral replication is required for a successful viral infection and requests virus capacity to acquire the macromolecules required for its propagation. To this end, viruses have adopted several strategies to harness cellular metabolism in accordance with their specific demands. Most viruses upregulate specific cellular anabolic pathways and are largely dependent on such alterations. RNA viruses, for example, upregulate both glycolysisand glycogenolysis providing TCA cycle intermediates essential for anabolic lipogenesis. Also, these infections usually induce the PPP, leading to increased nucleotide levels supporting viral replication. SARS-CoV-2 (the cause of COVID-19)that has so far spread from China throughout the world is also an RNA virus. Owing to the more metabolic plasticity of uninfected cells, a promising approach for specific antiviral therapy, which has drawn a lot of attention in the recent years, would be the targeting of metabolic changes induced by viruses. In the current review, we first summarize some of virus-induced metabolic adaptations and then based on these information as well as SARS-CoV-2 pathogenesis, propose a potential therapeutic modality for this calamitous world-spreading virus with the hope of employing this strategy for near-future clinical application.

In Vitro Inhibition of Zika Virus Replication with Poly(Sodium 4-Styrenesulfonate)

Zika virus (ZIKV) is an emerging mosquito-borne pathogen associated with microcephaly and other congenital abnormalities in newborns as well as neurologic complications in adults. The explosive transmission of the virus in the last ten years put it in the limelight and improved our understanding of its biology and pathology. Currently, no vaccine or drugs are available to prevent or treat ZIKV infections. Knowing the potential of flaviviruses to broaden their geographic distribution, as observed for the West Nile virus, it is of importance to develop novel antiviral strategies. In this work, we identified poly(sodium 4-styrenesulfonate) (PSSNa) as a new polymeric ZIKV inhibitor. We demonstrated that PSSNa inhibits ZIKV replication in vitro both in animal and human cells, while no cytotoxicity is observed. Our mechanistic studies indicated that PSSNa acts mostly through direct binding to ZIKV particle and blocking its attachment to the host cells.

Wogonin inhibits in vitro herpes simplex virus type 1 and 2 infection by modulating cellular NF-κB and MAPK pathways

BACKGROUND

Wogonin, a natural flavonoid-like chemical compound, exhibits anti-inflammatory, antitumor, antiviral, neuroprotective, and anxiolytic effects by modulating a variety of cellular signaling pathways including PI3K-Akt, p53, nuclear factor κB (NF-κB), mitogen-activated protein kinase (MAPK) pathways. In this study, its antiviral effect against herpes simplex virus (HSV) type 1 and 2 (HSV-1 and HSV-2) replication was investigated.

RESULTS

Wogonin suppressed HSV-2-induced cytopathic effect (CPE) and reduced viral mRNA transcription, viral protein synthesis, and infectious virion particle titers in a dose-dependent manner. A time-of-drug-addition assay demonstrated that wogonin acted as a postentry viral inhibitor. Wogonin also significantly reduced HSV-induced NF-κB and MAPK pathway activation, which has previously been demonstrated to be important for viral replication.

CONCLUSIONS

Our results suggest that the anti-herpes effect of wogonin may be mediated by modulation of cellular NF-κB and JNK/p38 MAPK pathways and imply that wogonin may be useful as an anti-HSV agent.

Highly Effective and Safe Polymeric Inhibitors of Herpes Simplex Virus in Vitro and in Vivo

A series of poly(ethylene glycol)-block-poly(3-(methacryloylamino)propyl trimethylammonium chloride) (PEG-b-PMAPTAC) water-soluble block copolymers consisting of PEG and PMPTAC were obtained by reversible addition-fragmentation chain-transfer (RAFT) polymerization and demonstrated to function as highly effective herpes simplex virus type 1 (HSV-1) inhibitors as shown by in vitro tests (Vero E6 cells) and in vivo experiments (mouse model). Half-maximal inhibitory concentration (IC₅₀) values were determined by quantitative polymerase chain reaction to be 0.36 ± 0.08 μg/mL for the most effective polymer PEG₄₅-b-PMAPTAC₅₂ and 0.84 ± 1.24 μg/mL for the less effective one, PEG₄₅-b-PMAPTAC₇₄. The study performed on the mouse model showed that the polymers protect mice from lethal infection. The polymers are not toxic to the primary human skin fibroblast cells up to the concentration of 100 μg/mL and to the Vero E6 cells up to 500 μg/mL. No systemic or topical toxicity was observed in vivo, even with mice treated with concentrated formulation (100 mg/mL). The mechanistic studies indicated that polymers interacted with the cell and blocked the formation of the entry/fusion complex. Physicochemical and biological properties of PEG_x-b-PMAPTAC_y make them promising drug candidates.

BX-795 inhibits HSV-1 and HSV-2 replication by blocking the JNK/p38 pathways without interfering with PDK1 activity in host cells

BX-795 is an inhibitor of 3-phosphoinositide-dependent kinase 1 (PDK1), but also a potent inhibitor of the IKK-related kinase, TANKbinding kinase 1 (TBK1) and IKKɛ. In this study we attempted to elucidate the molecular mechanism(s) underlying the inhibition of BX-795 on Herpes simplex virus (HSV) replication. HEC-1-A or Vero cells were treated with BX-795 and infected with HSV-1 or HSV-2 for different periods. BX-795 (3.125-25 μmol/L) dose-dependently suppressed HSV-2 replication, and displayed a low cytotoxicity to the host cells. BX-795 treatment dose-dependently suppressed the expression of two HSV immediate-early (IE) genes (ICP0 and ICP27) and the late gene (gD) at 12 h postinfection. HSV-2 infection resulted in the activation of PI3K and Akt in the host cells, and BX-795 treatment inhibited HSV-2-induced Akt phosphorylation and activation. However, the blockage of PI3K/Akt/mTOR with LY294002 and rapamycin did not affect HSV-2 replication. HSV-2 infection increased the phosphorylation of JNK and p38, and reduced ERK phosphorylation at 8 h postinfection in the host cells; BX-795 treatment inhibited HSV-2-induced activation of JNK and p38 MAP kinase as well as the phosphorylation of c-Jun and ATF-2, the downstream targets of JNK and p38 MAP kinase. Furthermore, SB203580 (a p38 inhibitor) or SP600125 (a JNK inhibitor) dose-dependently inhibited the viral replication in the host cells, whereas PD98059 (an ERK inhibitor) was not effective. Moreover, BX-795 blocked PMA-stimulated c-Jun activation as well as HSV-2-mediated c-Jun nuclear translocation. BX-795 dose-dependently inhibited HSV-2, PMA, TNF-α-stimulated AP-1 activation, but not HSV-induced NF-κB activation. Overexpression of p38/JNK attenuated the inhibitory effect of BX-795 on HSV replication. BX-795 completely blocked HSV-2-induced MKK4 phosphorylation, suggesting that BX-795 acting upstream of JNK and p38 MAP kinase. In conclusion, this study identifies the anti-HSV activity of BX-795 and its targeting of the JNK/p38 MAP kinase pathways in host cells.

Anti-HSV Activity of Kuwanon X from Mulberry Leaves with Genes Expression Inhibitory and HSV-1 Induced NF-κB Deactivated Properties

Six stilbene derivatives isolated from Mulberry leaves including Kuwanon X, Mulberrofuran C, Mulberrofuran G, Moracin C, Moracin M 3'-O-b-glucopyranoside and Moracin M were found to have antiviral effects against herpes simplex virus type 1 and 2 (HSV-1 and HSV-2) at different potencies except for Mulberrofuran G. Kuwanon X exhibited the greatest activity against HSV-1 15577 and clinical strains and HSV-2 strain 333 with IC₅₀ values of 2.2, 1.5 and 2.5 µg/mL, respectively. Further study revealed that Kuwanon X did not inactivate cell-free HSV-1 particles, but inhibited cellular adsorption and penetration of HSV-1 viral particles. Following viral penetration, Kuwanon X reduced the expression of HSV-1 IE and L genes, and decreased the synthesis of HSV-1 DNA. Furthermore, it was demonstrated that Kuwanon X inhibited the HSV-1-induced nuclear factor (NF)-κB activation through blocking the nuclear translocation and DNA binding of NF-κB. These results suggest that Kuwanon X exerts anti-HSV activity through multiple modes and could be a potential candidate for the therapy of HSV infection.

In search for effective and definitive treatment of herpes simplex virus type 1 (HSV-1) infections

Herpes Simplex Virus type 1 (HSV-1) is a nuclear replicating enveloped virus.

Basic chemokine-derived glycosaminoglycan binding peptides exert antiviral properties against dengue virus serotype 2, herpes simplex virus-1 and respiratory syncytial virus

Chemokines attract leukocytes to sites of infection in a G protein-coupled receptor (GPCR) and glycosaminoglycan (GAG) dependent manner. Therefore, chemokines are crucial molecules for proper functioning of our antimicrobial defense mechanisms. In addition, some chemokines have GPCR-independent defensin-like antimicrobial activities against bacteria and fungi. Recently, high affinity for GAGs has been reported for the positively charged COOH-terminal region of the chemokine CXCL9. In addition to CXCL9, also CXCL12γ has such a positively charged COOH-terminal region with about 50% positively charged amino acids. In this report, we compared the affinity of COOH-terminal peptides of CXCL9 and CXCL12γ for GAGs and KD values in the low nM range were detected. Several enveloped viruses such as herpesviruses, hepatitis viruses, human immunodeficiency virus (HIV), dengue virus (DENV), etc. are known to bind to GAGs such as the negatively charged heparan sulfate (HS). In this way GAGs are important for the initial contacts between viruses and host cells and for the infection of the cell. Thus, inhibiting the virus-cell interactions, by blocking GAG-binding sites on the host cell, might be a way to target multiple virus families and resistant strains. This article reports that the COOH-terminal peptides of CXCL9 and CXCL12γ have antiviral activity against DENV serotype 2, clinical and laboratory strains of herpes simplex virus (HSV)-1 and respiratory syncytial virus (RSV). Moreover, we show that CXCL9(74-103) competes with DENV envelope protein domain III for binding to heparin. These short chemokine-derived peptides may be lead molecules for the development of novel antiviral agents.

One-step solvothermal synthesis of highly water-soluble, negatively charged superparamagnetic Fe3O4 colloidal nanocrystal clusters

Highly charged hydrophilic superparamagnetic Fe3O4 colloidal nanocrystal clusters with an average diameter of 195 nm have been successfully synthesized using a modified one-step solvothermal method. Anionic polyelectrolyte poly(4-styrenesulfonic acid-co-maleic acid) sodium salt containing both sulfonate and carboxylate groups was used as the stabilizer. The clusters synthesized under different experimental conditions were characterized with transmission electron microscopy and dynamic light scattering; it was found that the size distribution and water dispersity were significantly affected by the concentration of the polyelectrolyte stabilizer and iron sources in the reaction mixtures. A possible mechanism involving novel gel-like large molecular networks that confined the nucleation and aggregation process was proposed and discussed. The colloidal nanocrystal clusters remained negatively charged in the experimental pH ranges from 2 to 11, and also showed high colloidal stability in phosphate buffered saline (PBS) and ethanol. These highly colloidal stable superparamagnetic Fe3O4 clusters could find potential applications in bioseparation, targeted drug delivery, and photonics.