Search

Human Respiratory syncytial virus (hRSV) mainly affects immunosuppressed patients requiring hospitalization. No specific treatment is financially accessible, and available vaccines do not cover all risk groups. During hRSV infection, there is a robust neutrophilic influx into the airways. hRSV-activated neutrophils release substantial neutrophil extracellular traps (NETs) in lung tissue, comprising DNA, histones, cytosolic, and granular proteins. NETs form mucus buildup in the lungs, compromising respiratory capacity and neutralizing viral particles. Understanding responsible NETs molecules requires improvement. We evaluated NETs interacting with hRSV particles and their contribution to anti-hRSV NET effects. Immunoblotting, immunoprecipitation, and peptide sequencing assays confirmed hRSV binding to a 50-75 kDa NET protein, Myeloperoxidase (MPO). MPO, a microbicide enzyme in NETs, interacts with hRSV, likely at F0 protein (site IV) on the viral surface. Additionally, MPO (32 μM) and NETs (0.4 μg/mL) reduced in vitro replication of clinical (hRSV A and B) and laboratory (Long) hRSV isolates by approximately 30 %, reversible by selective MPO inhibitor (PF-06281355; 48 μM). Thus, MPO contributes to virucidal NET effects on diverse hRSV strains, enhancing comprehension of NETs' role in infection and aiding treatment strategies for respiratory diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The Human Respiratory Syncytial Virus (RSV) is the leading cause of acute respiratory infections in children. Currently, no safe, effective, or feasible option for pharmacological management of RSV exists. Hence, plant-derived natural compounds have been explored as promising antiviral agents. Mangifera indica is a globally distributed plant with reported anti-inflammatory, cardioprotective, and antiviral activities. Our study investigated the antiviral potential of a novel pectin from M. indica peels (PMi) and its chemically sulfated derivative (PSMi) against RSV in HEp-2 cells. The compounds were characterized using Fourier-transform infrared spectroscopy and nuclear magnetic resonance (NMR). NMR analysis revealed the presence of ester and carboxylic acid groups in PMi, and sulfation resulted in a sulfation degree of 0.5. PMi and PSMi showed no cytotoxic effects even at concentrations as high as 2000 μg/mL. PSMi completely inhibited RSV infectivity (100-1.56 μg/mL, 50 % inhibitory concentration of viral infectivity = 0.77 ± 0.11 μg/mL). The mechanism of action was investigated using the 50 % tissue culture infectious dose assay . PSMi displayed virucidal activity at concentrations from 100 to 6.25 μg/mL, and a significant reduction in viral infection was observed at all treatment times. Overall, PSMi is antiviral, cell-safe, and exhibits promising potential as an RSV treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Photoinduced hyperthermia with nanomaterials has been proven effective in photothermal therapy (PTT) of tumor tissues, but a precise control in PTT requires determination of the molecular-level mechanisms. In this paper, we determined the mechanisms responsible for the action of photoexcited gold shell-isolated nanoparticles (AuSHINs) in reducing the viability of MCF7 (glandular breast cancer) and especially A549 (lung adenocarcinoma) cells in vitro experiments, while the photoinduced damage to healthy cells was much smaller. The photoinduced effects were more significant than using other nanomaterials, and could be explained by the different effects from incorporating AuSHINs on Langmuir monolayers from lipid extracts of tumoral (MCF7 and A549) and healthy cells. The incorporation of AuSHINs caused similar expansion of the Langmuir monolayers, but Fourier-transform infrared spectroscopy (FTIR) data of Langmuir-Schaefer films (LS) indicated distinct levels of penetration into the monolayers. AuSHINs penetrated deeper into the A549 extract monolayers, affecting the vibrational modes of polar groups and carbon chains, while in MCF7 monolayers penetration was limited to the surroundings of the polar groups. Even smaller insertion was observed for monolayers of the healthy cell extract. The photochemical reactions were modulated by AuSHINs penetration, since upon irradiation the surface area of A549 monolayer decreased owing to lipid chain cleavage by oxidative reactions. For MCF7 monolayers, hydroperoxidation under illumination led to a ca. 5% increase in surface area. The monolayers of healthy cell lipid extract were barely affected by irradiation, consistent with the lowest degree of AuSHINs insertion. In summary, efficient photothermal therapy may be devised by producing AuSHINs capable of penetrating the chain region of tumor cell membranes., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Metallic nanoparticles are promising agents for photothermal cancer therapy (PTT) owing to their photostability and efficient light-to-heat conversion, but their possible aggregation remains an issue. In this paper, we report on the photoinduced heating of gold shell-isolated nanoparticles (AuSHINs) in in vitro experiments to kill human oropharyngeal (HEp-2) and breast (BT-474 and MCF-7) carcinoma cells, with cell viability reducing below 50 % with 2.2 × 10 12 AuSHINs/mL and 6 h of incubation. This toxicity to cancer cells is significantly higher than in previous works with gold nanoparticles. Considering the AuSHINs dimensions we hypothesize that cell uptake is not straightforward, and the mechanism of action involves accumulation on phospholipid membranes as the PTT target for photoinduced heating and subsequent generation of reactive oxygen species (ROS). Using Langmuir monolayers as simplified membrane models, we confirmed that AuSHINs have a larger effect on 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS), believed to represent cancer cell membranes, than on 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) taken as representative of healthy eukaryotic cells. In particular, data from polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) revealed an increased conformational order of DOPS tails due to the stronger adsorption of AuSHINs. Furthermore, light irradiation reduced the stability of AuSHINs containing DOPC and DOPS monolayers owing to oxidative reactions triggered by ROS upon photoinduced heating. Compared to DOPC, DOPS lost nearly twice as much material to the subphase, which is consistent with a higher rate of ROS formation in the vicinity of the DOPS monolayer., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Artepillin C is the main compound present in propolis from Baccharis dracunculifolia, whose antitumor activity has been the focus of many studies. Herein, we shall investigate the Artepillin C mechanisms of action against cells derived from the oropharyngeal carcinoma (HEp-2). Cytotoxicity tests revealed that the concentrations of Artepillin C required to reduce cell viability by 50% (CC 50 ) are dependent on the incubation time, decreasing from 40.7 × 10 -5  mol/L to 15.7 × 10 -5  mol/L and 9.05 × 10 -5  mol/L considering 12, 24 and 48 h, respectively. Hydrophobic interactions on neutral species of Artepillin C induce aggregation over the HEp-2 plasma membrane, given the acid conditions of the cellular culture. Indeed, Langmuir monolayers mimicking cellular membranes of tumor cells revealed Artepillin C affinity to interact with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) containing 20 mol% of 1,2-dipalmitoyl-sn-glychero-3-phosphoserine (DPPS), leading aggregation on giant unilamellar vesicles (GUVs) at pH 3.2. Moreover, leakage experiments on GUVs have shown that the presence of DPPS enhances the efflux of the fluorescent probe signaling the membrane permeabilization, which is the origin of the necrotic pathway triggered in HEp-2 cells, as observed by flow cytometry assays., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

hRSV is the major causative agent of acute respiratory infections. Among its eleven proteins, M2-1 is a transcription antiterminator, making it an interesting target for antivirals. Quercetin is a flavonol which inhibits some virus infectivity and replication. In the present work, the M2-1 gene was cloned, expressed and the protein was purified. Thermal stability and secondary structure were analyzed by circular dichroism and the interaction with Quercetin was evaluated by fluorescence spectroscopy. Molecular docking experiments were performed to understand this mechanism of interaction. The purified protein is mainly composed of α-helix, with a melting temperature of 328.6K (≈55°C). M2-1 titration with Quercetin showed it interacts with two sites, one with a strong constant association K1 (site 1≈1.5×10 6 M -1 ) by electrostatic interactions, and another with a weak constant association K2 (site 2≈1.1×10 5 M -1 ) by a hydrophobic interaction. Ligand's docking shows it interacts with the N-terminus face in a more polar pocket and, between the domains of oligomerization and RNA and P protein interaction, in a more hydrophobic pocket, as predicted by experimental data. Therefore, we postulated this ligand could be interacting with important domains of the protein, avoiding viral replication and budding., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The macrophage-derived neutrophil chemotactic factor (MNCF) is an alpha-galactoside-binding lectin, known to induce dexamethasone-insensitive neutrophil recruitment. We further characterized MNCF effects on neutrophils and showed that it shares with TNF-alpha the ability to delay apoptosis and to trigger degranulation. MNCF and TNF-alpha effects show similar kinetics and involve Src kinases and MAPKinases dependent pathways. They were, however, clearly distinguished, since the soluble TNF-receptor etanercept prevented TNF but not MNCF effects, while melibiose disaccharide inhibited MNCF but not TNF effects. Absorption of MNCF on detoxi-gel did not alter its properties, precluding an LPS contamination effect. By contrast, galectin-3 required LPS to activate neutrophils. Specific antibodies allowed to further demonstrate that MNCF and galectin-3 are two distinct molecules. Finally, MNCF- and IL-8-induced neutrophil activation differed by their kinetic and sensitivity to pertussis toxin. In conclusion, MNCF is a distinct neutrophil agonist, with pro-inflammatory activities involving its carbohydrate recognition domain.