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

Synthesis and Characterization of Maghemite Nanoparticles Functionalized with Poly(Sodium 4-Styrene Sulfonate) Saloplastic and Its Acute Ecotoxicological Impact on the Cladoceran Daphnia magna

Using a modified co-precipitation method, 11(2) nm γ-Fe2O3 nanoparticles functionalized with PSSNa [Poly(sodium 4-styrenesulfonate)] saloplastic polymer were successfully synthesized, and their structural, vibrational, electronic, thermal, colloidal, hyperfine, and magnetic properties were systematically studied using various analytic techniques. The results showed that the functionalized γ-Fe2O3/PSSNa nanohybrid has physicochemical properties that allow it to be applied in the magnetic remediation process of water. Before being applied as a nanoadsorbent in real water treatment, a short-term acute assay was developed and standardized using a Daphnia magna biomarker. The ecotoxicological tests indicated that the different concentrations of the functionalized nanohybrid may affect the mortality of the Daphnia magna population during the first 24 h of exposure. A lethal concentration of 533(5) mg L-1 was found. At high concentrations, morphological changes were also seen in the body, heart, and antenna. Therefore, these results suggested the presence of alterations in normal growth and swimming skills. The main changes observed in the D. magna features were basically caused by the PSSNa polymer due to its highly stable colloidal properties (zeta potential > -30 mV) that permit a direct and constant interaction with the Daphnia magna neonates.

Antiviral Activities of Heparan Sulfate Mimetic RAFT Polymers Against Mosquito-borne Viruses

Mosquito-borne viruses are a major worldwide health problem associated with high morbidity and mortality rates and significant impacts on national healthcare budgets. The development of antiviral drugs for both the treatment and prophylaxis of these diseases is thus of considerable importance. To address the need for therapeutics with antiviral activity, a library of heparan sulfate mimetic polymers was screened against dengue virus (DENV), Yellow fever virus (YFV), Zika virus (ZIKV), and Ross River virus (RRV). The polymers were prepared by RAFT polymerization of various acidic monomers with a target MW of 20 kDa (average Mn ∼ 27 kDa by GPC). Among the polymers, poly(SS), a homopolymer of sodium styrenesulfonate, was identified as a broad spectrum antiviral with activity against all the tested viruses and particularly potent inhibition of YFV (IC50 = 310 pM). Our results further uncovered that poly(SS) exhibited a robust inhibition of ZIKV infection in both mosquito and human cell lines, which points out the potential functions of poly(SS) in preventing mosquito-borne viruses associated diseases by blocking viral transmission in their mosquito vectors and mitigating viral infection in patients.

Curcumin-Poly(sodium 4-styrenesulfonate) Conjugates as Potent Zika Virus Entry Inhibitors

Curcumin, a natural product with recognized antiviral properties, is limited in its application largely due to its poor solubility. This study presents the synthesis of water-soluble curcumin-poly(sodium 4-styrenesulfonate) (Cur-PSSNan) covalent conjugates. The antiflaviviral activity of conjugates was validated in vitro by using the Zika virus as a model. In the development of these water-soluble curcumin-containing derivatives, we used the macromolecules reported by us to also hamper viral infections. Mechanistic investigations indicated that the conjugates exhibited excellent stability and bioavailability. The curcumin and macromolecules in concerted action interact directly with virus particles and block their attachment to host cells, hampering the infection process.

Poly(ethylene glycol)-block-poly(sodium 4-styrenesulfonate) Copolymers as Efficient Zika Virus Inhibitors: In Vitro Studies

A series of poly(ethylene glycol)-block-poly(sodium 4-styrenesulfonate) (PEG-b-PSSNa) copolymers were synthesized, and their antiviral activity against Zika virus (ZIKV) was determined. The polymers inhibit ZIKV replication in vitro in mammalian cells at nontoxic concentrations. The mechanistic analysis revealed that the PEG-b-PSSNa copolymers interact directly with viral particles in a zipper-like mechanism, hindering their interaction with the permissive cell. The antiviral activity of the copolymers is well-correlated with the length of the PSSNa block, indicating that the copolymers' ionic blocks are biologically active. The blocks of PEG present in copolymers studied do not hinder that interaction. Considering the practical application of PEG-b-PSSNa and the electrostatic nature of the inhibition, the interaction between the copolymers and human serum albumin (HSA) was evaluated. The formation of PEG-b-PSSNa-HSA complexes in the form of negatively charged nanoparticles well-dispersed in buffer solution was observed. That observation is promising, given the possible practical application of the copolymers.

Self-Organized Nanoparticles of Random and Block Copolymers of Sodium 2-(acrylamido)-2-methyl-1-propanesulfonate and Sodium 11-(acrylamido)undecanoate as Safe and Effective Zika Virus Inhibitors

A series of anionic homopolymers, poly(sodium 2-(acrylamido)-2-methyl-1-propanesulfonate) (PAMPS) and amphiphilic copolymers of AMPS and sodium 11-(acrylamido)undecanoate (AaU), both block (PAMPS₇₅-b-PAaU_n), and random (P(AMPS_m-co-AaU_n)), were synthesized and their antiviral activity against Zika virus (ZIKV) was evaluated. Interestingly, while the homopolymers showed limited antiviral activity, the copolymers are very efficient antivirals. This observation was explained considering that under the conditions relevant to the biological experiments (pH 7.4 PBS buffer) the macromolecules of these copolymers exist as negatively charged (zeta potential about −25 mV) nanoparticles (4–12 nm) due to their self-organization. They inhibit the ZIKV replication cycle by binding to the cell surface and thereby blocking virus attachment to host cells. Considering good solubility in aqueous media, low toxicity, and high selectivity index (SI) of the PAMPS-b-PAaU copolymers, they can be considered promising agents against ZIKV infections.

Efficacy of sodium polyanethol sulfonate on herpes simplex virus-1 infection in vitro

Objective: To investigate the effect of sodium polyanethol sulfonate (SPS) on herpes simplex virus type 1 (HSV-1) infection in vitro.

Methods

Human corneal epithelial (HCE-T) cells and Vero cells were infected with HSV-1 [HSV-1 f strain, HSV-1f; HSV-1-H129 with green fluorescent protein (GFP) knock-in, HSV-1g]. SPS was added to the culture medium at various concentrations in time-of-addition assay. Experiments including photography of fluorescence in HSV-1g or plaque formation by HSV-1f, western blot assays, real-time RT-PCR assays, cytopathic effect inhibition assays, cytotoxicity assays, and viral absorption and penetration assays were performed to explore the antiviral effect and mechanism of the compounds.

Results

We identified that SPS reduced the replication of HSV-1 in HCE-T and Vero cells in a dose-dependent manner. HSV-1g fluorescence was reduced by 66.3% and 65.4% in HCE-T and Vero cells, respectively, after treatment with 0.4 µg/ml SPS. Furthermore, the viral fluorescence intensities were inhibited by SPS in a dose-dependent manner when the viruses or cells were preincubated with SPS. Relative levels of the ICP4 protein and VP16 mRNA were decreased by SPS in a dose-dependent manner. Moreover, the IC₅₀ values of SPS for HSV-1g and HSV-1f in HCE-T cells were 0.69±0.09 μg/ml and 1.63±0.44 μg/ml, respectively. Even 10,000 µg/ml SPS had no obvious cytotoxicity toward HCE-T and Vero cells. Importantly, viral absorption and penetration assays showed that the relative fluorescence intensity of HSV-1g was significantly reduced by SPS in a dose-dependent manner in the absorption test, but no change was observed in the penetration test.

Conclusions

SPS inhibits HSV-1 replication in HCE-T and Vero cells, indicating that SPS has the potential for treating HSV-1 infection, particularly HSV-1 keratitis.