A novel antiviral formulation inhibits a range of enveloped viruses

SARS-CoV-2 Seropositivity in Urban Population of Wild Fallow Deer, Dublin, Ireland, 2020-2022

SARS-CoV-2 can infect wildlife, and SARS-CoV-2 variants of concern might expand into novel animal reservoirs, potentially by reverse zoonosis. White-tailed deer and mule deer of North America are the only deer species in which SARS-CoV-2 has been documented, raising the question of whether other reservoir species exist. We report cases of SARS-CoV-2 seropositivity in a fallow deer population located in Dublin, Ireland. Sampled deer were seronegative in 2020 when the Alpha variant was circulating in humans, 1 deer was seropositive for the Delta variant in 2021, and 12/21 (57%) sampled deer were seropositive for the Omicron variant in 2022, suggesting host tropism expansion as new variants emerged in humans. Omicron BA.1 was capable of infecting fallow deer lung type-2 pneumocytes and type-1-like pneumocytes or endothelial cells ex vivo. Ongoing surveillance to identify novel SARS-CoV-2 reservoirs is needed to prevent public health risks during human-animal interactions in periurban settings.

ORFV entry into host cells via clathrin-mediated endocytosis and macropinocytosis

Orf virus (ORFV), also known as infectious pustular virus, leads to an acute contagious zoonotic infectious disease. ORFV can directly contact and infect epithelial cells of skin and mucosa, causing damage to tissue cells. So far, the pathway of ORFV entry into cells is unclear. Therefore, finding the internalization pathway of ORFV will help to elucidate the cellular and molecular mechanisms of ORFV infection and invasion, which in turn will provide a certain reference for the prevention and treatment of ORFV. In the present study, chemical inhibitors were used to analyze the mechanism of ORFV entry into target cells. The results showed that the inhibitor of clathrin-mediated endocytosis could inhibit ORFV entry into cells. However, the inhibitor of caveolae-mediated endocytosis cannot inhibit ORFV entry into cells. In addition, inhibition of macropinocytosis pathway also significantly reduced ORFV internalization. Furthermore, the inhibitors of acidification and dynamin also prevented ORFV entry. However, results demonstrated that inhibitors inhibited ORFV entry but did not inhibit ORFV binding. Notably, extracellular trypsin promoted ORFV entry into cells directly, even when the endocytic pathway was inhibited. In conclusion, ORFV enters into its target cells by clathrin-mediated endocytosis and macropinocytosis, while caveolae-dependent endocytosis has little effects on this process. In addition, the entry into target cells by ORFV required an acid environment and the effect of dynamin. Meanwhile, we emphasize that broad-spectrum antiviral inhibitors and extracellular enzyme inhibitors are likely to be effective strategies for the prevention and treatment of ORFV infection.

A novel antiviral formulation containing caprylic acid inhibits SARS-CoV-2 infection of a human bronchial epithelial cell model

A novel proprietary formulation, ViruSAL, has previously been demonstrated to inhibit diverse enveloped viral infections in vitro and in vivo. We evaluated the ability of ViruSAL to inhibit SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) infectivity, using physiologically relevant models of the human bronchial epithelium, to model early infection of the upper respiratory tract. ViruSAL potently inhibited SARS-CoV-2 infection of human bronchial epithelial cells cultured as an air-liquid interface (ALI) model, in a concentration- and time-dependent manner. Viral infection was completely inhibited when ViruSAL was added to bronchial airway models prior to infection. Importantly, ViruSAL also inhibited viral infection when added to ALI models post-infection. No evidence of cellular toxicity was detected in ViruSAL-treated cells at concentrations that completely abrogated viral infectivity. Moreover, intranasal instillation of ViruSAL to a rat model did not result in any toxicity or pathological changes. Together these findings highlight the potential for ViruSAL as a novel and potent antiviral for use within clinical and prophylactic settings.

Antiviral activity of nano-monocaprin against Phi6 as a surrogate for SARS-CoV-2

The COVID-19 pandemic involving SARS-CoV-2 has raised interest in using antimicrobial lipid formulations to inhibit viral entry into their host cells or to inactivate them. Lipids are a part of the innate defense mechanism against pathogens. Here, we evaluated the use of nano-monocaprin (NMC) in inhibiting enveloped (phi6) and unenveloped (MS2) bacteriophages. NMC was prepared using the sonochemistry technique. Size and morphology analysis revealed the formation of ~ 8.4 ± 0.2-nm NMC as measured by dynamic light scattering. We compared the antiviral activity of NMC with molecular monocaprin (MMC) at 0.5 mM and 2 mM concentrations against phi6, which we used as a surrogate for SARS-CoV-2. The synthesized NMC exhibited 50% higher antiviral activity against phi6 than MMC at pH 7 using plaque assay. NMC inactivated phi6 stronger at pH 4 than at pH 7. To determine if NMC is toxic to mammalian cells, we used MTS assay to assess its IC₅₀ for HPDE and HeLa cell lines, which were ~ 203 and 221 µM, respectively. NMC may be used for prophylactic application either as a drop or spray since many viruses enter the human body through the mucosal lining of the nose, eyes, and lungs.

Metabolomic and transcriptomic signatures of influenza vaccine response in healthy young and older adults

Seasonal influenza causes mild to severe respiratory infections and significant morbidity, especially in older adults. Transcriptomic analysis in populations across multiple flu seasons has provided insights into the molecular determinants of vaccine response. Still, the metabolic changes that underlie the immune response to influenza vaccination remain poorly characterized. We performed untargeted metabolomics to analyze plasma metabolites in a cohort of younger and older subjects before and after influenza vaccination to identify vaccine-induced molecular signatures. Metabolomic and transcriptomic data were combined to define networks of gene and metabolic signatures indicative of high and low antibody response in these individuals. We observed age-related differences in metabolic baselines and signatures of antibody response to influenza vaccination and the abundance of α-linolenic and linoleic acids, sterol esters, fatty-acylcarnitines, and triacylglycerol metabolism. We identified a metabolomic signature associated with age-dependent vaccine response, finding increased tryptophan and decreased polyunsaturated fatty acids (PUFAs) in young high responders (HRs), while fatty acid synthesis and cholesteryl esters accumulated in older HRs. Integrated metabolomic and transcriptomic analysis shows that depletion of PUFAs, which are building blocks for prostaglandins and other lipid immunomodulators, in young HR subjects at Day 28 is related to a robust immune response to influenza vaccination. Increased glycerophospholipid levels were associated with an inflammatory response in older HRs to flu vaccination. This multi-omics approach uncovered age-related molecular markers associated with influenza vaccine response and provides insight into vaccine-induced metabolic responses that may help guide development of more effective influenza vaccines.

Repurposing an In Vitro Measles Virus Dissemination Assay for Screening of Antiviral Compounds

Measles virus (MV) is a highly contagious respiratory virus responsible for outbreaks associated with significant morbidity and mortality among children and young adults. Although safe and effective measles vaccines are available, the COVID-19 pandemic has resulted in vaccination coverage gaps that may lead to the resurgence of measles when restrictions are lifted. This puts individuals who cannot be vaccinated, such as young infants and immunocompromised individuals, at risk. Therapeutic interventions are complicated by the long incubation time of measles, resulting in a narrow treatment window. At present, the only available WHO-advised option is treatment with intravenous immunoglobulins, although this is not approved as standard of care. Antivirals against measles may contribute to intervention strategies to limit the impact of future outbreaks. Here, we review previously described antivirals and antiviral assays, evaluate the antiviral efficacy of a number of compounds to inhibit MV dissemination in vitro, and discuss potential application in specific target populations. We conclude that broadly reactive antivirals could strengthen existing intervention strategies to limit the impact of measles outbreaks.

Measles

Measles is a highly contagious, potentially fatal, but vaccine-preventable disease caused by measles virus. Symptoms include fever, maculopapular rash, and at least one of cough, coryza, or conjunctivitis, although vaccinated individuals can have milder or even no symptoms. Laboratory diagnosis relies largely on the detection of specific IgM antibodies in serum, dried blood spots, or oral fluid, or the detection of viral RNA in throat or nasopharyngeal swabs, urine, or oral fluid. Complications can affect many organs and often include otitis media, laryngotracheobronchitis, pneumonia, stomatitis, and diarrhoea. Neurological complications are uncommon but serious, and can occur during or soon after the acute disease (eg, acute disseminated encephalomyelitis) or months or even years later (eg, measles inclusion body encephalitis and subacute sclerosing panencephalitis). Patient management mainly involves supportive therapy, such as vitamin A supplementation, monitoring for and treatment of secondary bacterial infections with antibiotics, and rehydration in the case of severe diarrhoea. There is no specific antiviral therapy for the treatment of measles, and disease control largely depends on prevention. However, despite the availability of a safe and effective vaccine, measles is still endemic in many countries and causes considerable morbidity and mortality, especially among children in resource-poor settings. The low case numbers reported in 2020, after a worldwide resurgence of measles between 2017 and 2019, have to be interpreted cautiously, owing to the effect of the COVID-19 pandemic on disease surveillance. Disrupted vaccination activities during the pandemic increase the potential for another resurgence of measles in the near future, and effective, timely catch-up vaccination campaigns, strong commitment and leadership, and sufficient resources will be required to mitigate this threat.

Rosin Soap Exhibits Virucidal Activity

Chemical methods of virus inactivation are used routinely to prevent viral transmission in both a personal hygiene capacity but also in at-risk environments like hospitals. Several virucidal products exist, including hand soaps, gels, and surface disinfectants. Resin acids, which can be derived from tall oil, produced from trees, have been shown to exhibit antibacterial activity. However, whether these products or their derivatives have virucidal activity is unknown. Here, we assessed the capacity of rosin soap to inactivate a panel of pathogenic mammalian viruses in vitro. We show that rosin soap can inactivate human enveloped viruses: influenza A virus (IAV), respiratory syncytial virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For IAV, rosin soap could provide a 100,000-fold reduction in infectivity. However, rosin soap failed to affect the nonenveloped encephalomyocarditis virus (EMCV). The inhibitory effect of rosin soap against IAV infectivity was dependent on its concentration but not on the incubation time or temperature. In all, we demonstrate a novel chemical inactivation method against enveloped viruses, which could be of use for preventing virus infections in certain settings.

IMPORTANCE Viruses remain a significant cause of human disease and death, most notably illustrated through the current coronavirus disease 2019 (COVID-19) pandemic. Control of virus infection continues to pose a significant global health challenge to the human population. Viruses can spread through multiple routes, including via environmental and surface contamination, where viruses can remain infectious for days. Methods for inactivating viruses on such surfaces may help mitigate infection. Here, we present evidence identifying a novel virucidal product, rosin soap, which is produced from tall oil from coniferous trees. Rosin soap was able to rapidly and potently inactivate influenza virus and other enveloped viruses.

Lipid Nanoparticle Technology for Delivering Biologically Active Fatty Acids and Monoglycerides

There is enormous interest in utilizing biologically active fatty acids and monoglycerides to treat phospholipid membrane-related medical diseases, especially with the global health importance of membrane-enveloped viruses and bacteria. However, it is difficult to practically deliver lipophilic fatty acids and monoglycerides for therapeutic applications, which has led to the emergence of lipid nanoparticle platforms that support molecular encapsulation and functional presentation. Herein, we introduce various classes of lipid nanoparticle technology and critically examine the latest progress in utilizing lipid nanoparticles to deliver fatty acids and monoglycerides in order to treat medical diseases related to infectious pathogens, cancer, and inflammation. Particular emphasis is placed on understanding how nanoparticle structure is related to biological function in terms of mechanism, potency, selectivity, and targeting. We also discuss translational opportunities and regulatory needs for utilizing lipid nanoparticles to deliver fatty acids and monoglycerides, including unmet clinical opportunities.

Chemical compositions and experimental and computational modeling activity of sea cucumber Holothuria parva ethanolic extract against herpes simplex virus type 1

Sea cucumber has antiviral activities against various viruses including herpes simplex virus type 1 (HSV-1). The purpose of the current study was to determine the chemical profile and inhibitory effects of tegument ethanolic extract of Holothuria parva on HSV-1 infection and to elucidate the mechanism of antiviral action of this marine invertebrate. Cytotoxic activity of the extract on Vero cell line was determined using the methyl thiazolyl tetrazolium (MTT) method. The different components in H. parva were determined by GC-MS analysis. To assess the antiviral activity of the extract, MTT and 50% tissue culture infective dose (TCID50) were applied. Finally, computational molecular docking was performed to screen the potential binding ability of extract contents with HSV-1 surface glycoproteins and host cell surface receptors. Using MTT assay, the non-cytotoxic concentration of the extract was measured 46.5 μg/mL. Octadecanoic acid 2-hydroxy-1-(hydroxymethyl) ethyl ester and 2',6'-acetoxylidide were two major constituents in the H. parva extract. Pre-treatment of HSV-1 with the ethanolic extract of H. parva led to a 2.1 log10 TCID50 reduction in virus titers when compared to the control group (P = 0.002). The log10 TCID50 reductions relative to the control group for co-penetration and post-penetration assays were 1.5 (P = 0.009) and 0.7 (P = 0.09), respectively. The tegument ethanolic extract of H. parva has significant antiviral properties against HSV-1. Docking analysis demonstrated that compounds of the extract [lidocaine and 2-hydroxy-1-(hydroxymethyl) ethyl ester octadecanoic acid] may cover similarly both virus and host cells binding domains leading to interference in virus attachment to cell receptors.

Nanoemulsions: The rising star of antiviral therapeutics and nanodelivery system-current status and prospects

Nanoemulsions (NEs) of essential oil (EO) have significant potential to target microorganisms, especially viruses. They act as a vehicle for delivering antiviral drugs and vaccines. Narrowing of drug discovery pipeline and the emergence of new viral diseases, especially, coronavirus disease, have created a niche to use NEs for augmenting currently available therapeutic options. Published literature demonstrated that EOs have an inherent broad spectrum of activity across bacterial, fungal, and viral pathogens. The emulsification process significantly improved the efficacy of the active ingredients in the EOs. This article highlights the research findings and patent developments in the last 2 years especially, in EO antiviral activity, antiviral drug delivery, vaccine delivery, viral resistance development, and repurposing EO compounds against SARS-CoV-2.

Stopping Membrane-Enveloped Viruses with Nanotechnology Strategies: Toward Antiviral Drug Development and Pandemic Preparedness

Membrane-enveloped viruses are a leading cause of viral epidemics, and there is an outstanding need to develop broad-spectrum antiviral strategies to treat and prevent enveloped virus infections. In this review, we critically discuss why the lipid membrane surrounding enveloped virus particles is a promising antiviral target and cover the latest progress in nanotechnology research to design and evaluate membrane-targeting virus inhibition strategies. These efforts span diverse topics such as nanomaterials, self-assembly, biosensors, nanomedicine, drug delivery, and medical devices and have excellent potential to support the development of next-generation antiviral drug candidates and technologies. Application examples in the areas of human medicine and agricultural biosecurity are also presented. Looking forward, research in this direction is poised to strengthen capabilities for virus pandemic preparedness and demonstrates how nanotechnology strategies can help to solve global health challenges related to infectious diseases.