Tolerance to colibactin correlates with homologous recombination proficiency and resistance to irinotecan in colorectal cancer cells

The bacterial genotoxin colibactin promotes colorectal cancer (CRC) tumorigenesis, but systematic assessment of its impact on DNA repair is lacking, and its effect on response to DNA-damaging chemotherapeutics is unknown. We find that CRC cell lines display differential response to colibactin on the basis of homologous recombination (HR) proficiency. Sensitivity to colibactin is induced by inhibition of ATM, which regulates DNA double-strand break repair, and blunted by HR reconstitution. Conversely, CRC cells chronically infected with colibactin develop a tolerant phenotype characterized by restored HR activity. Notably, sensitivity to colibactin correlates with response to irinotecan active metabolite SN38, in both cell lines and patient-derived organoids. Moreover, CRC cells that acquire colibactin tolerance develop cross-resistance to SN38, and a trend toward poorer response to irinotecan is observed in a retrospective cohort of CRCs harboring colibactin genomic island. Our results shed insight into colibactin activity and provide translational evidence on its chemoresistance-promoting role in CRC.

Antibacterial and Antiviral Activities of Silver Nanocluster/Silica Composite Coatings Deposited onto Air Filters

The indoor air quality should be better controlled and improved to avoid numerous health issues. Even if different devices are developed for air filtration, the proliferation of microorganisms under certain conditions must be controlled. For this purpose, a silver nanocluster/silica composite coating was deposited via a cosputtering technique onto fiber glass and polymeric based substrates. The aim of this work is focused on the evaluation of the antibacterial and antiviral effects of the developed coating. The preliminary results of the compositional and morphological tests showed an evenly distributed coating on filters surfaces. Several antibacterial tests were performed, confirming strong effect both in qualitative and quantitative methods, against S. epidermidis and E. coli. To understand if the coating can stop the proliferation of bacteria colonies spread on it, simulation of everyday usage of filters was performed, nebulizing bacteria solution with high colonies concentration and evaluating the inhibition of bacteria growth. Additionally, a deep understanding of the virucidal action and mechanism of Ag nanoclusters of the coating was performed. The effect of the coating both in aqueous medium and in dry methods was evaluated, in comparison with analysis on ions release. The virucidal performances are assessed against the human coronavirus OC43 strain (HCoV-OC43).

Early introduction of simulation in the medical curriculum: the MedInTo perspective

Despite the increasing body of evidence supporting the use of simulation in medicine, a question remains: when should we introduce it into the medical school's curriculum? We present the experience and future perspectives of the MD program in Medicine and Surgery of University of Turin-MedInTo. Since its launch, MedInTo has been dedicated to integrating innovative teaching approaches at the early stages into the medical curriculum. Herewith, we describe a case-based approach for our activities, which includes the utilization of simulation for emergency medical care training for students and the integration of virtual and augmented reality technology. Dedicated surgical training activities using virtual-augmented reality and life-like simulator for students are also described.

The estimated prevalence of antiphospholipid antibodies and criteria-antiphospholipid syndrome in subjects with renal thrombotic microangiopathy

BACKGROUND

While the prevalence of antiphospholipid antibodies (aPL) in venous and arterial thrombotic events had already been estimated by previous studies, the prevalence of aPL in subjects with Thrombotic Microangiopathy (TMA) is still not fully elucidated. Thus, we conducted a systematic review to estimate the frequency of aPL in subjects with biopsy-proven renal TMA.

METHODS

We conducted in the PubMed database a search for English-language studies investigating the presence of aPL in subjects with biopsy-proven renal TMA from January 1985 to December 2022. Keywords used in the search included: 'antiphospholipid syndrome', 'antiphospholipid antibodies' and 'thrombotic microangiopathy'. Cohorts of HUS patients were excluded due to the risk of over-estimating the prevalence of aPL in these populations. The median frequency for positive aPL including anticardiolipin antibodies (aCL), antibodies against β2-glycoprotein-I (anti-β2GPI) and lupus anticoagulant (LA) was then calculated.

RESULTS

522 articles were identified through the literature search. Six studies, assessing the prevalence of aPL in 211 subjects with renal TMA, were retrieved. The overall aPL prevalence was estimated as 24.4% (range 22-56). The estimated prevalence of aCL (IgG/IgM), anti-β2GPI, (IgG/IgM) and LA was 4.0% (range 3-27), 4.0% (range 3-16) and 18.9% (range 13-25), respectively. APS was diagnosed in 16.3% (range 11-29) of the patients. Of note, a high level of heterogeneity was observed when comparing the reported aPL profiles for each study.

CONCLUSIONS

This comprehensive systematic analysis of studies investigating the prevalence of aPL in renal TMA showed that, despite the high heterogeneity of the included studies, aPL are present in about one case out of four renal-TMA cases.

Viruses and Human Milk: Transmission or Protection?

Human milk (HM) is considered the best source of nutrition for infant growth and health. This nourishment is unique and changes constantly during lactation to adapt to the physiological needs of the developing infant. It is also recognized as a potential route of transmission of some viral pathogens although the presence of a virus in HM rarely leads to a disease in an infant. This intriguing paradox can be explained by considering the intrinsic antiviral properties of HM. In this comprehensive and schematically presented review, we have described what viruses have been detected in HM so far and what their potential transmission risk through breastfeeding is. We have provided a description of all the antiviral compounds of HM, along with an analysis of their demonstrated and hypothesized mechanisms of action. Finally, we have also analyzed the impact of HM pasteurization and storage methods on the detection and transmission of viruses, and on the antiviral compounds of HM. We have highlighted that there is currently a deep knowledge on the potential transmission of viral pathogens through breastfeeding and on the antiviral properties of HM. The current evidence suggests that, in most cases, it is unnecessarily to deprive an infant of this high-quality nourishment and that the continuation of breastfeeding is in the best interest of the infant and the mother.

Enhanced Anti-Herpetic Activity of Valacyclovir Loaded in Sulfobutyl-ether-β-cyclodextrin-decorated Chitosan Nanodroplets

Valacyclovir (VACV) was developed as a prodrug of the most common anti-herpetic drug Acyclovir (ACV), aiming to enhance its bioavailability. Nevertheless, prolonged VACV oral treatment may lead to the development of important side effects. Nanotechnology-based formulations for vaginal administration represent a promising approach to increase the concentration of the drug at the site of infection, limiting systemic drug exposure and reducing systemic toxicity. In this study, VACV-loaded nanodroplet (ND) formulations, optimized for vaginal delivery, were designed. Cell-based assays were then carried out to evaluate the antiviral activity of VACV loaded in the ND system. The chitosan-shelled ND exhibited an average diameter of about 400 nm and a VACV encapsulation efficiency of approximately 91% and was characterized by a prolonged and sustained release of VACV. Moreover, a modification of chitosan shell with an anionic cyclodextrin, sulfobutyl ether β-cyclodextrin (SBEβCD), as a physical cross-linker, increased the stability and mucoadhesion capability of the nanosystem. Biological experiments showed that SBEβCD-chitosan NDs enhanced VACV antiviral activity against the herpes simplex viruses type 1 and 2, most likely due to the long-term controlled release of VACV loaded in the ND and an improved delivery of the drug in sub-cellular compartments.

Impact of time-temperature combinations on the anti-Cytomegalovirus activity and biological components of human milk

BACKGROUND

There is extensive evidence that Holder pasteurization (HoP) (30 min at 62.5 °C) has harmful effects on the bioactivities of human milk (HM). We previously demonstrated that lowering HoP temperature is sufficient to inactivate Cytomegalovirus (HCMV). Here, we analyzed the effect of lowering time/temperature on the antiviral activity against HCMV and IgA levels of HM.

METHODS

Eighty HM samples from five mothers were pasteurized in a range of temperature (62.5-56 °C) and time (40-10 min) in a conventional setting of Human Milk Bank. Unpasteurized HM from each mother was used as control. The samples were assayed against HCMV-AD169 strain in cell cultures and IgA levels were determined by ELISA.

RESULTS

All HM samples exhibited anti-HCMV activity, to a different extent. An improvement of antiviral activity was observed in samples treated at 60, 58 and 56 °C compared to those at 62.5 °C, with ID50 values near those of unpasteurized milk. Similarly, better retention in IgA levels was observed by reducing the temperature of treatment.

CONCLUSIONS

We demonstrated that a 2.5 °C reduction of heat treatment significantly preserved the IgA content and fully restored the anti-HCMV activity of HM, supporting this variant of HoP as a valid alternative to preserve HM bioactivities.

IMPACT

This work questions the standard HoP and opens the debate on whether the pasteurization temperature commonly used in Human Milk Banks should be lowered to better preserve the biological components of the milk. A reduction of HoP temperature at 60 °C determined a significant preservation of anti-HCMV activity and IgA content of donor HM, compared to standard HoP. This alternative HoP is highly feasible compared to other substitute pasteurization techniques, since it would employ the same pasteurizer equipment found in most Human Milk Banks.

Gallium(III)- and Thallium(III)-Encapsulated Polyoxopalladates: Synthesis, Structure, Multinuclear NMR, and Biological Activity Studies

Three gallium(III)- and thallium(III)-containing polyoxopalladates (POPs) have been synthesized and structurally characterized in the solid state and in solution, namely, the phosphate-capped 12-palladate nanocubes [XPd12O8(PO4)8]13- (X = GaIII, GaPd12P8; X = TlIII, TlPd12P8) and the 23-palladate double-cube [Tl2IIIPd23P14O70(OH)2]20- (Tl2Pd23P14). The cuboid POPs, GaPd12P8 and TlPd12P8, are solution stable as verified by the respective 31P, 71Ga, and 205Tl nuclear magnetic resonance (NMR) spectra. Of prime interest, the spin-spin coupling schemes allowed for an intimate study of the solution behavior of the TlIII-containing POPs via a combination of 31P and 205Tl NMR, including the stoichiometry of the major fragments of Tl2Pd23P14. Moreover, biological studies demonstrated the antitumor and antiviral activity of GaPd12P8 and TlPd12P8, which were validated to be as efficient as cis-platinum against human melanoma and acute promyelocytic leukemia cells. Furthermore, GaPd12P8 and TlPd12P8 exerted inhibitory activity against two herpetic viruses, HSV-2 and HCMV, in a dose-response manner.

Hard-Shelled Glycol Chitosan Nanoparticles for Dual MRI/US Detection of Drug Delivery/Release: A Proof-of-Concept Study

This paper describes a novel nanoformulation for dual MRI/US in vivo monitoring of drug delivery/release. The nanosystem was made of a perfluoropentane core coated with phospholipids stabilized by glycol chitosan crosslinked with triphosphate ions, and it was co-loaded with the prodrug prednisolone phosphate (PLP) and the structurally similar MRI agent Gd-DTPAMA-CHOL. Importantly, the in vitro release of PLP and Gd-DTPAMA-CHOL from the nanocarrier showed similar profiles, validating the potential impact of the MRI agent as an imaging reporter for the drug release. On the other hand, the nanobubbles were also detectable by US imaging both in vitro and in vivo. Therefore, the temporal evolution of both MRI and US contrast after the administration of the proposed nanosystem could report on the delivery and the release kinetics of the transported drug in a given lesion.

Long-lasting neutralizing antibodies and T cell response after the third dose of mRNA anti-SARS-CoV-2 vaccine in multiple sclerosis

Background and objectives

Long lasting immune response to anti-SARS-CoV-2 vaccination in people with Multiple Sclerosis (pwMS) is still largely unexplored. Our study aimed at evaluating the persistence of the elicited amount of neutralizing antibodies (Ab), their activity and T cell response after three doses of anti-SARS-CoV-2 vaccine in pwMS.

Methods

We performed a prospective observational study in pwMS undergoing SARS-CoV-2 mRNA vaccinations. Anti-Region Binding Domain (anti-RBD) of the spike (S) protein immunoglobulin G (IgG) titers were measured by ELISA. The neutralization efficacy of collected sera was measured by SARS-CoV-2 pseudovirion-based neutralization assay. The frequency of Spike-specific IFNγ-producing CD4+ and CD8+ T cells was measured by stimulating Peripheral Blood Mononuclear Cells (PBMCs) with a pool of peptides covering the complete protein coding sequence of the SARS-CoV-2 S.

Results

Blood samples from 70 pwMS (11 untreated pwMS, 11 under dimethyl fumarate, 9 under interferon-γ, 6 under alemtuzumab, 8 under cladribine, 12 under fingolimod and 13 under ocrelizumab) and 24 healthy donors were collected before and up to six months after three vaccine doses. Overall, anti-SARS-CoV-2 mRNA vaccine elicited comparable levels of anti-RBD IgGs, neutralizing activity and anti-S T cell response both in untreated, treated pwMS and HD that last six months after vaccination. An exception was represented by ocrelizumab-treated pwMS that showed reduced levels of IgGs (p<0.0001) and a neutralizing activity under the limit of detection (p<0.001) compared to untreated pwMS. Considering the occurrence of a SARS-CoV-2 infection after vaccination, the Ab neutralizing efficacy (p=0.04), as well as CD4+ (p=0.016) and CD8+ (p=0.04) S-specific T cells, increased in treated COVID+ pwMS compared to uninfected treated pwMS at 6 months after vaccination.

Discussion

Our follow-up provides a detailed evaluation of Ab, especially in terms of neutralizing activity, and T cell responses after anti-SARS-CoV-2 vaccination in MS context, over time, considering a wide number of therapies, and eventually breakthrough infection. Altogether, our observations highlight the vaccine response data to current protocols in pwMS and underline the necessity to carefully follow-up anti-CD20- treated patients for higher risk of breakthrough infections. Our study may provide useful information to refine future vaccination strategies in pwMS.

Identification of oxysterol synthetic analogs as a novel class of late-stage inhibitors of herpes simplex virus 2 replication

Genital herpes, most frequently caused by herpes simplex virus 2 (HSV-2) infection, is one of the most prevalent sexually transmitted infections. The current rationale for the treatment of HSV-2 infection involves nucleoside analogs (e.g. acyclovir) to suppress reactivation. Enzymatic oxysterols are endogenous 27-carbon atoms molecules produced by enzymatic cholesterol oxidation, and recently emerged as a broad-spectrum host targeting antivirals. In this study, we screened selected members of an in-house synthesized library of oxysterol analogues for their activity against HSV-2, identifying three compounds, named PFM064, PFM067, and PFM069, endowed with 50% effective concentrations (EC₅₀) in the micromolar range, without exerting any apparent cytotoxicity. Moreover, the results obtained showed the ability of the novel derivatives to inhibit both cell-to-cell fusion induced by HSV-2, and the production of an intracellular viral progeny. Further experiments performed with PFM067 (which was selected for more-in-depth studies as the most effective synthetic analog) showed that these molecules act in a late stage of HSV-2 replicative cycle, by sequestering viral glycoproteins in the Golgi compartment, and likely inhibiting the nuclear egress of neo-synthetized viral capsids. Taken together, these results point to PFM067 as a promising chemical scaffold for the development of novel herpetic antivirals.

Abstract 5900: Tolerance to colibactin correlates with response to chemotherapeutic agents in colorectal cancer

Introduction: The bacterial genotoxin colibactin is enriched in colorectal cancer (CRC) and promotes the accumulation of mutations that drive tumorigenesis. However, systematic assessment of its impact on DNA damage response is lacking and the effect of colibactin exposure on response to other genotoxic agents (such as chemotherapy) is missing.

Materials and Methods: We implemented an in vitro bacteria-coculture system to assess the effect of colibactin on a representative subset of 40 molecularly and pharmacologically annotated CRC cell lines and in a panel of isogenic DDR KO cell lines we generated. We further validated our results in patient-derived organoids. Finally, we recapitulated prolonged exposure to colibactin occurring during tumorigenesis by chronically infecting sensitive cells until the emergence of a tolerant phenotype.}

Results: We found that different cell lines display specific sensitivity to colibactin’s genotoxic stress: while colibactin-tolerant cells are capable to quickly and efficiently repair colibactin-induced DNA damage, sensitive cells lack this ability. Moreover, we found that homologous recombination (HR) proficiency discriminates colibactin-tolerant cells, which display higher levels of RAD51 foci (as marker of activation of HR) compared to sensitive cells upon infection with colibactin. Screening of isogenic DDR KO cell lines revealed that genetic inactivation of the intertwined pathways of HR (through KO of ATM) and replication stress (RS) response (through KO of ATRIP) significantly sensitized cells to colibactin. In addition, we found that restoration of HR activity was sufficient to induce a colibactin-tolerant phenotype in initially sensitive cell lines. Notably, thanks to a previous effort of pharmacological characterization of CRC cell lines in our lab, we found a significant correlation between sensitivity to colibactin and irinotecan active metabolite SN38, but not oxaliplatin. We validated the same correlation in patient-derived organoids annotated for response to SN38. While colibactin, SN38 and oxaliplatin all induced RS in treated cells, we found that colibactin and SN38 showed a similar DNA damage response which involved activation of ATM. Finally, chronic re-infection of sensitive, HR-deficient CRC cells with colibactin selected a tolerant phenotype characterized by restoration of HR activity. Of translational relevance, colibactin-tolerant derivative cells acquired cross-resistance to SN38 and PARP inhibitor olaparib but not to oxaliplatin.

Conclusion: Our results shed novel insight into colibactin’s genotoxic mechanism and support a model in which colibactin both promotes tumorigenesis and acts as an evolutionary bottleneck which selects HR proficient CRC cells. Furthermore, our study provides preclinical evidence on colibactin’s role in promoting chemoresistance in colorectal cancer.

Citation Format: Alberto Sogari, Emanuele Rovera, Nicole Megan Reilly, Simona Lamba, Mariangela Russo, Annalisa Lorenzato, Erika Durinikova, Livio Trusolino, Sabrina Arena, Manuela Donalisio, Federica Di Nicolantonio, David Lembo, Alberto Bardelli. Tolerance to colibactin correlates with response to chemotherapeutic agents in colorectal cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5900.

Silver Nanoparticles: Review of Antiviral Properties, Mechanism of Action and Applications

New antiviral drugs and new preventive antiviral strategies are a target of intense scientific interest. Thanks to their peculiar properties, nanomaterials play an important role in this field, and, in particular, among metallic materials, silver nanoparticles were demonstrated to be effective against a wide range of viruses, in addition to having a strong antibacterial effect. Although the mechanism of antiviral action is not completely clarified, silver nanoparticles can directly act on viruses, and on their first steps of interaction with the host cell, depending on several factors, such as size, shape, functionalization and concentration. This review provides an overview of the antiviral properties of silver nanoparticles, along with their demonstrated mechanisms of action and factors mainly influencing their properties. In addition, the fields of potential application are analyzed, demonstrating the versatility of silver nanoparticles, which can be involved in several devices and applications, including biomedical applications, considering both human and animal health, environmental applications, such as air filtration and water treatment, and for food and textile industry purposes. For each application, the study level of the device is indicated, if it is either a laboratory study or a commercial product.

Exploration of novel hexahydropyrrolo[1,2-e]imidazol-1-one derivatives as antiviral agents against ZIKV and USUV

Zika virus (ZIKV) and Usutu virus (USUV) are two emerging flaviviruses mostly transmitted by mosquitos. ZIKV is associated with microcephaly in newborns and the less-known USUV, with its reported neurotropism and its extensive spread in Europe, represents a growing concern for human health. There is still no approved vaccine or specific antiviral against ZIKV and USUV infections. The main goal of this study is to investigate the anti-ZIKV and anti-USUV activity of a new library of compounds and to preliminarily investigate the mechanism of action of the selected hit compounds in vitro. Two potent anti-ZIKV and anti-USUV agents, namely ZDL-115 and ZDL-116, were discovered, both presenting low cytotoxicity, cell-line independent antiviral activity in the low micromolar range and ability of reducing viral progeny production. The analysis of the structure-activity relationship (SAR) revealed that introduction of 2-deoxyribose to 3-arene was fundamental to enhance the solubility and improve the antiviral action. Additionally, we demonstrated that ZDL-115 and ZDL-116 are significantly active against both viruses when added on cells for at least 24 h prior to viral inoculation or immediately post-infection. The docking analysis showed that ZDL-116 could target the host vitamin D receptor (VDR) and viral proteins. Future experiments will be focused on compound modification to discover analogues that are more potent and on the clarification of the mechanism of action and the specific drug target. The discovery and the development of a novel anti-flavivirus drug will have a significant impact in a context where there are no fully effective antiviral drugs or vaccines for most flaviviruses.

The role of bacteria and viruses in Behçet syndrome: Should we move towards new paradigms?

The etiological complexity of Behçet syndrome (BS), an immune-mediated rare form of vasculitis characterized by multi-organ involvement, is still elusive due to an incomplete understanding of the synergy between genetic susceptibility, environmental triggers, and an abnormal immune response. Long-standing theories regarding the origins of BS include the involvement of infectious organisms supporting an aberrant immunological response through different mechanisms, including molecular mimicry. Additionally, it has been demonstrated that the BS phenotypes are linked to oral and gut microbiome dysbiosis, which is a dynamic reservoir of millions of microbes containing proteins and metabolites that can mimic the autoantigens. Infections, including viral pathogens, could potentially trigger the inflammation and symptoms of BS. In this review, we aim to describe the available evidence on the cross-talk between BS and infections in order to discuss potential clinical implications and possible therapeutic targets.

Identification of a βCD-Based Hyper-Branched Negatively Charged Polymer as HSV-2 and RSV Inhibitor

Cyclodextrins and cyclodextrin derivatives were demonstrated to improve the antiviral potency of numerous drugs, but also to be endowed with intrinsic antiviral action. They are suitable building blocks for the synthesis of functionalized polymer structures with potential antiviral activity. Accordingly, four water-soluble hyper-branched beta cyclodextrin (βCD)-based anionic polymers were screened against herpes simplex virus (HSV-2), respiratory syncytial virus (RSV), rotavirus (HRoV), and influenza virus (FluVA). They were characterized by FTIR-ATR, TGA, elemental analyses, zeta-potential measurements, and potentiometric titrations, while the antiviral activity was investigated with specific in vitro assays. The polymer with the highest negative charge, pyromellitic dianhydride-linked polymer (P_PMDA), showed significant antiviral action against RSV and HSV-2, by inactivating RSV free particles and by altering HSV-2 binding to the cell. The polymer fraction with the highest molecular weight showed the strongest antiviral activity and both P_PMDA and its active fractions were not toxic for cells. Our results suggest that the polymer virucidal activity against RSV can be exploited to produce new antiviral materials to counteract the virus dissemination through the air or direct contact. Additionally, the strong HSV-2 binding inhibition along with the water solubility of P_PMDA and the acyclovir complexation potential of βCD are attractive features for developing new therapeutic topical options against genital HSV-2 infection.

27-Hydroxycholesterol inhibits rhinovirus replication in vitro and on human nasal and bronchial histocultures without selecting viral resistant variants

The genetic plasiticity of viruses is one of the main obstacles to the development of antivirals. The aim of this study has been to assess the ability of two physiologic oxysterols and host-targeting antivirals - namely 25- and 27-hydroxycholesterol (25OHC and 27OHC) - to select resistant strains, using human rhinovirus (HRV) as a challenging model of a viral quasispecies. Moreover, we selected 27OHC for further studies aimed at exploring its potential for the development of antiviral drugs. The results obtained with clonal or serial passage approaches show that 25OHC and 27OHC do not select HRV oxysterol-resistant variants. Moreover, we demonstrate the ability of 27OHC to inhibit the yield of HRV in 3D in vitro fully reconstituted human nasal and bronchial epithelia from cystic fibrosis patients and prevent virus-induced cilia damage. The promising antiviral activity of 27OHC and its competitive advantages over direct-acting antivirals, make this molecule a suitable candidate for further studies to explore its clinical potential.

Human milk glycosaminoglycans inhibit cytomegalovirus and respiratory syncytial virus infectivity by impairing cell binding

BACKGROUND

The antiviral role of glycosaminoglycans in human milk (HM-GAGs) has been poorly investigated. They are highly sulfated polysaccharides, which were proposed to act as decoy receptors according to their structure. The aim of this study is to evaluate the antiviral potential and the mechanism of action of total and individual HM-GAGs against three pediatric clinically relevant viruses: respiratory syncytial virus (RSV), cytomegalovirus (HCMV), and rotavirus.

METHODS

HM-GAGs were isolated from HM and a library of individual GAGs, structurally related to HM-GAGs, was prepared. The antiviral activity of HM-GAGs and the impact of thermal treatment were investigated in vitro by specific antiviral assays.

RESULTS

We demonstrated that HM-GAGs are endowed with anti-HCMV and anti-RSV activity and that they act by altering virus attachment to cell. We clarified the contribution of individual HM-GAGs, showing a specific structure-related activity. We did not observe any alteration of HM-GAG antiviral activity after thermal treatment.

CONCLUSIONS

We showed that HM-GAGs contribute to the overall antiviral activity of HM, likely exerting a synergic action with other HM antiviral agents. HM-GAGs can now be added to the list of endogenous factors that may reduce breast-milk-acquired HCMV symptomatic infections and protecting infants from respiratory tract infections by RSV.

IMPACT

HM-GAGs have been poorly investigated for their antiviral action so far. We demonstrated that HM-GAGs are endowed with significant anti-HCMV and anti-RSV activity and that they are able to alter virus binding to the cell. The contribution of individual HM-GAGs is mainly exerted by the FMHep and is not based on a simple charge interaction between the virus and sulfate groups but involves a specific GAG structural configuration. Our results contribute to identifying the multiple factors synergically acting in mediating HM antiviral properties and to clarifying their specific mechanism of action.

Link between SARS-CoV-2 emissions and airborne concentrations: Closing the gap in understanding

The airborne transmission of SARS-CoV-2 remains surprisingly controversial; indeed, health and regulatory authorities still require direct proof of this mode of transmission. To close this gap, we measured the viral load of SARS-CoV-2 of an infected subject in a hospital room (through an oral and nasopharyngeal swab), as well as the airborne SARS-CoV-2 concentration in the room resulting from the person breathing and speaking. Moreover, we simulated the same scenarios to estimate the concentration of RNA copies in the air through a novel theoretical approach and conducted a comparative analysis between experimental and theoretical results. Results showed that for an infected subject's viral load ranging between 2.4 × 10⁶ and 5.5 × 10⁶ RNA copies mL^-1, the corresponding airborne SARS-CoV-2 concentration was below the minimum detection threshold when the person was breathing, and 16.1 (expanded uncertainty of 32.8) RNA copies m^-3 when speaking. The application of the predictive approach provided concentrations metrologically compatible with the available experimental data (i.e. for speaking activity). Thus, the study presented significant evidence to close the gap in understanding airborne transmission, given that the airborne SARS-CoV-2 concentration was shown to be directly related to the SARS-CoV-2 emitted. Moreover, the theoretical analysis was shown to be able to quantitatively link the airborne concentration to the emission.

The Peptide A-3302-B Isolated from a Marine Bacterium Micromonospora sp. Inhibits HSV-2 Infection by Preventing the Viral Egress from Host Cells

Herpesviruses are highly prevalent in the human population, and frequent reactivations occur throughout life. Despite antiviral drugs against herpetic infections, the increasing appearance of drug-resistant viral strains and their adverse effects prompt the research of novel antiherpetic drugs for treating lesions. Peptides obtained from natural sources have recently become of particular interest for antiviral therapy applications. In this work, we investigated the antiviral activity of the peptide A-3302-B, isolated from a marine bacterium, Micromonospora sp., strain MAG 9-7, against herpes simplex virus type 1, type 2, and human cytomegalovirus. Results showed that the peptide exerted a specific inhibitory activity against HSV-2 with an EC50 value of 14 μM. Specific antiviral assays were performed to investigate the mechanism of action of A-3302-B. We demonstrated that the peptide did not affect the expression of viral proteins, but it inhibited the late events of the HSV-2 replicative cycle. In detail, it reduced the cell-to-cell virus spread and the transmission of the extracellular free virus by preventing the egress of HSV-2 progeny from the infected cells. The dual antiviral and previously reported anti-inflammatory activities of A-3302-B, and its effect against an acyclovir-resistant HSV-2 strain are attractive features for developing a therapeutic to reduce the transmission of HSV-2 infections.

Wastewater-based SARS-CoV-2 environmental monitoring for Piedmont, Italy

The experience gained over the last hundred years clearly indicates that two groups of viruses represent the main risk for the development of highly transmissible epidemics and pandemics in the human species: influenza viruses and coronaviruses (CoV). Although the search for viruses with pandemic potential in the environment may have an important predictive and monitoring role, it is still based on empirical methodologies, mostly resulting from the clinic and not fully validated for environmental matrices. As far as the SARS-CoV-2 pandemic, currently underway, is concerned, environmental monitoring activities aiming at checking the presence of SARS-CoV-2 in wastewater can be extremely useful to predict and check the diffusion of the disease. For this reason, the present study aims at evaluating the SARS-CoV-2 diffusion by means of a wastewater-based environmental monitoring developed in Piedmont, N-W Italy, during the second and third pandemic waves. Wastewater sampling strategies, sampling points sample pre-treatments and analytical methods, data processing and standardization, have been developed and discussed to give representative and reliable results. The following outcomes has been highlighted by the present study: i) a strong correlation between SARS-CoV-2 concentration in untreated wastewater and epidemic evolution in the considered areas can be observed as well as a predictive potential that could provide decision-makers with indications to implement effective policies, to mitigate the effects of the ongoing pandemic and to prepare response plans for future pandemics that could certainly arise in the decades to come; ii) moreover, the data at disposal from our monitoring campaign (almost 500 samples analysed in 11 months) confirm that SARS-CoV-2 concentrations in wastewater are strongly variable and site-specific across the region: the highest SARS-CoV-2 concentration values have been found in sewer networks serving the most populated areas of the region; iii) normalization of viral concentrations in wastewater through Pepper Mild Mottle Virus (a specific faecal marker) has been carried out and commented; iv) the study highlights the potential of wastewater treatment plants to degrade the genetic material referable to SARS-CoV-2 as well. In conclusion, the preliminary data reported in the present paper, although they need to be complemented by further studies considering also other geographical regions, are very promising.

SARS-CoV-2 airborne transmission: A validated sampling and analytical method

The airborne transmission path for SARS-CoV-2 is of primary scientific and health-related interest as it could actually involve management, accessibility, use and functionality of many activities, including hospitals), schools, workplaces, factories, transport, sport venues and outdoor environment. It is necessary to develop a sampling and analytical method for virus-laden bioaerosol that could be considered reliable and validated according to ISO/IEC 17025 requirements. The present paper defines sample pretreatments aiming at recover SARS-CoV-2 from glass-fiber and PTFE filters employed by low and high-volume air samplers. Recovery test results focused on the sample concentration step carried out by means of ultracentrifugation are reported as well. Human coronavirus strain OC43 (a surrogate β-coronavirus with the same SARS-CoV-2 particle structure) was used to validate each step of the recovery tests. We found that the elution efficiency of coronavirus OC43 from glass-fiber and quartz filters could be strongly enhanced by using an elution buffer containing up to 40% of fetal calf serum. Moreover, the recovery from PTFE filters is much higher and easier than from glass-fiber filters: for glass-fiber filters a 3 h-shaking phase, followed by a 30 s-vortexing step, are necessary to elute viral infective particles; for PTFE, 60 min-shaking is enough. The effect of suction time on filters could be resumed as follows: sampling durations up to 20 min at a flow rate of 500 L/min do not affect recovery efficiencies from 10 cm glass-fiber filters, whereas the recovery efficiency of infectious virions from 4.7 cm PTFE filters decreases of a factor 2 after 3 h of sampling at a flow rate of 20 L/min. The recovery efficiency of ultracentrifugation turns out to be around 57%. The effect of storage temperature of filters immersed in a transport medium on coronavirus infectivity is assessed as well. Based on the sampling techniques and the analytical methods developed as described in the present study, many field tests were carried out reporting virus concentrations up to 50 genomic copies per cubic meter of air in domestic environment with poor ventilation condition, whereas in hospital wards the detectable concentrations of SARS-CoV-2 were generally lower than 10 genomic copies per cubic meter of air.

Trend of 25-hydroxycholesterol and 27-hydroxycholesterol plasma levels in patients affected by active chronic hepatitis B virus infection and inactive carriers

Hepatitis B virus (HBV) infection is a global health problem with different immunological phases and therapeutic approaches. The serological condition of inactive carrier (IC) was recently well defined as a clinical and virological stable status, in which specific treatment is usually deferred, while the active chronic hepatitis B (CHB) condition requires an immediate treatment strategy. Recently, a possible broad antiviral effect of oxysterols, in particular 25-hydroxycholesterol (25OHC) and 27-hydroxycholesterol (27OHC), was observed, as most likely linked to the positive modulation of innate immunity, but no clear evidence is available about their possible role in chronic HBV infection. Thus, we examined the relationship between the plasma levels of oxysterols and the disease condition of 40 HBV patients, without treatment at the start of the study. Of these, 33 were ICs and 7 were active CHB subjects. A marked reduction of 25OHC and 27OHC plasma levels was detectable in all active CHB recruited patients, while the plasma values observed in ICs all remained within the physiological range. No difference was observed between the two groups of patients with regard to the plasma levels of 24-hydroxycholesterol (24OHC). Further, the plasma level of 27OHC ≥ 140 μg/L was shown to be predictive of an inactive carrier status. This cohort study points to 27OHC as a good candidate biomarker to differentiate active and inactive CHB status. An increasing bulk of research reports is supporting the very likely contribution of this oxysterol to the immunological control of chronic hepatitis B.

SARS-CoV-2 and indoor/outdoor air samples: a methodological approach to have consistent and comparable results

Since the beginning of coronavirus disease 2019 (COVID-19) pandemic, large attention has been focused on the relationship between SARS-CoV-2 diffusion and environment. As a matter of fact, clear evidence of the transmission of SARS-CoV-2 via respiratory aerosol would be of primary importance; at the same time, checking the presence of SARS-CoV-2 in wastewater can be extremely useful to control the diffusion of the disease. Up to now, many studies report SARS-CoV-2 concentrations in indoor/outdoor air samples or water/wastewater samples that can differ by order of magnitude. Unfortunately, complete information about the scientific approach of many studies is still missing, relating to: samplers and sampling materials performances, recovery tests, measurement uncertainty, robustness, detection and quantification limits, infectivity of captured virus, virus degradation during sampling, influence of sample pre-treatments (included freezing) on results, effects of inhibitors, sample alterations due to manipulation, validation of methods and processes, quality assurance according to ISO/IEC 17025 requirements. Based on the first experiences focused on the presence of SARS-CoV-2 in environmental samples such as air quality filters or impingers collection solutions, the present study describes a coherent preliminary approach to SARS-CoV-2 indoor and outdoor air sampling in order to overcome the evident lack of standardization. Three aspects are highlighted here: the first solution to assure quality and consistency to air sampling relies on the development of recovery tests using standard materials and investigating sampling materials, sampling techniques, sampling durations, sample conservation and pre-treatments; secondly, in order to overcome the shortcomings of every single sampling technique, coupling different samplers in parallel sampling could be an efficient strategy to collect more information and make data more reliable; finally, with regards to airborne virus sampling, the results could be confirmed by simplified emission and dilution models.

Nanostructured composite coating endowed with antiviral activity against human respiratory viruses deposited on fibre-based air filters

The widespread of viral airborne diseases is becoming a critical problem for human health and safety, not only for the common cold and flu, but also considering more serious infection as the current pandemic COVID-19. Even if the current heating, ventilating and air conditioning (HVAC) systems limit the disease transmission by air, the air filters are susceptible to microbial colonization. In addition, viruses spread via droplets (aerosol) produced by direct or indirect contact with infected people. In this context, the necessity of an efficient HVAC system, able to capture and inactivate viruses- and bacteria-rich aerosols, thus preserving a safe indoor air environment and protecting people, is of enormous importance. The aim of this work is the assessment of the antiviral properties of a silver nanoclusters/silica composite coating deposited via co-sputtering technique on glass, on metallic fibre-based air filters as well as on cotton textiles. The selected human respiratory viruses are: respiratory syncytial virus (RSV), the human rhinovirus (HRV) and the influenza virus type A (FluVA). The coated air filters show that the nanostructured coating develops a strong virucidal activity against RSV and FluVA, but not against the HRV.

Combined in silico and in vitro approaches identified the antipsychotic drug lurasidone and the antiviral drug elbasvir as SARS-CoV2 and HCoV-OC43 inhibitors

The current emergency of the novel coronavirus SARS-CoV2 urged the need for broad-spectrum antiviral drugs as the first line of treatment. Coronaviruses are a large family of viruses that already challenged humanity in at least two other previous outbreaks and are likely to be a constant threat for the future. In this work we developed a pipeline based on in silico docking of known drugs on SARS-CoV1/2 RNA-dependent RNA polymerase combined with in vitro antiviral assays on both SARS-CoV2 and the common cold human coronavirus HCoV-OC43. Results showed that certain drugs displayed activity for both viruses at a similar inhibitory concentration, while others were specific. In particular, the antipsychotic drug lurasidone and the antiviral drug elbasvir showed promising activity in the low micromolar range against both viruses with good selectivity index.

Human Colostrum and Derived Extracellular Vesicles Prevent Infection by Human Rotavirus and Respiratory Syncytial Virus in Vitro

BACKGROUND

It is known that breastfeeding protects the infant from enteric and respiratory infections; however, the antiviral properties of human milk against enteric and respiratory viruses are largely unexplored.

RESEARCH AIMS

To explore the antiviral activity of human preterm colostrum against rotavirus and respiratory syncytial virus and to assess whether the derived extracellular vesicle contribute to this activity.

METHODS

We used a cross-sectional, prospective two-group non-experimental design. Colostra were collected from mothers of preterm newborns (N = 10) and extracellular vesicles were purified and characterized. The antiviral activity of colostra and derived extracellular vesicles were tested in vitro against rotavirus and respiratory syncytial virus and the step of viral replication inhibited by extracellular vesicles was investigated.

RESULTS

Each sample of colostrum and colostrum-derived extracellular vesicles had significant antiviral activity with a wide interpersonal variability. Mechanism of action studies demonstrated that extracellular vesicles acted by interfering with the early steps of the viral replicative cycle.

CONCLUSION

We demonstrated the intrinsic antiviral activity of human colostrum against rotavirus and respiratory syncytial virus and we showed that extracellular vesicles substantially contribute to the overall protective effect. Our results contribute to unravelling novel mechanisms underlying the functional role of human milk as a protective and therapeutic agent in preterm infants.

Effect of industrial processing and storage procedures on oxysterols in milk and milk products

Oxysterols are products of enzymatic and/or chemical cholesterol oxidation. While some of the former possess broad antiviral activities, the latter mostly originate from the deterioration of the nutritional value of foodstuff after exposure to heat, light, radiation and oxygen, raising questions about their potential health risks. We evaluated the presence of selected oxysterols in bovine colostrum and monitored the evolution of their cholesterol ratio throughout an entire industrial-scale milk production chain and after industrially employed storage procedures of milk powders. We report here for the first time the presence of high levels of the enzymatic oxysterol 27-hydroxycholesterol (27OHC) in concentrations of antiviral interest in bovine colostrum (87.04 ng mL^-1) that decreased during the first postpartum days (56.35 ng mL^-1). Of note, this oxysterol is also observed in milk and milk products and is not negatively affected by industrial processing or storage. We further highlight an exponential increase of the non-enzymatic oxysterols 7β-hydroxycholesterol (7βOHC) and 7-ketocholesterol (7KC) in both whole (WMPs) and skimmed milk powders (SMPs) during prolonged storage, confirming their role as reliable biomarkers of cholesterol oxidation over time: after 12 months, 7βOHC reached in both SMPs and WMPs amounts that have been found to be potentially toxic in vitro (265.46 ng g^-1 and 569.83 ng g^-1, respectively). Interestingly, industrial processes appeared to affect the generation of 7βOHC and 7KC differently, depending on the presence of fat in the product: while their ratios increased significantly after skimming and processing of skimmed milk and milk products, this was not observed after processing whole milk and milk cream.

Analysis of Thermal Sensitivity of Human Cytomegalovirus Assayed in the Conventional Conditions of a Human Milk Bank

One of the main concerns in human milk banks (HMB) is the transmission of human cytomegalovirus (HCMV) that could be present in the milk of infected women. There are consistent data showing that this virus is destroyed by Holder pasteurization (62.5°C for 30 min), but there is a lack of information about the response of the virus to the treatment at lower temperatures in strict HMB conditions. In order to analyze the effectiveness of different temperatures of pasteurization to eliminate HCMV in human milk, a preliminary assay was performed incubating HCMV-spiked raw milk samples from donor mothers at tested temperatures in a PCR thermocycler and the viral infectivity was assayed on cell cultures. No signs of viral replication were observed after treatments at temperatures equal or >53°C for 30, 20, and 10 min, 58°C for 5 min, 59°C for 2 min, and 60°C for 1 min. These data were confirmed in a pasteurizer-like model introducing HCMV-spiked milk in disposable baby bottles. No viral infectivity was detected on cell cultures after heating treatment of milk for 30 min at temperatures from 56 to 60°C. Thus, our results show that by using conventional pasteurization conditions, temperatures in the range of 56-60°C are enough to inactivate HCMV. Consequently, we consider that, in order to provide a higher quality product, the current recommendation to pasteurize both mother's own milk and donated milk at 62.5°C must be re-evaluated.

Punica granatum Leaf Ethanolic Extract and Ellagic Acid as Inhibitors of Zika Virus Infection

Zika virus, an arthropod-borne flavivirus, is an emerging healthcare threat worldwide. Zika virus is responsible for severe neurological effects, such as paralytic Guillain-Barrè syndrome, in adults, and also congenital malformations, especially microcephaly. No specific antiviral drugs and vaccines are currently available, and treatments are palliative, but medicinal plants show great potential as natural sources of anti-Zika phytochemicals. This study deals with the investigation of the composition, cytotoxicity, and anti-Zika activity of Punica granatum leaf ethanolic extract, fractions, and phytoconstituents. P. granatum leaves were collected from different areas in Italy and Greece in different seasons. Crude extracts were analyzed and fractionated, and the pure compounds were isolated. The phytochemical and biomolecular fingerprint of the pomegranate leaves was determined. The antiviral activities of the leaf extract, fractions, and compounds were investigated against the MR766 and HPF2013 Zika virus strains in vitro. Both the extract and its fractions were found to be active against Zika virus infection. Of the compounds isolated, ellagic acid showed particular anti-Zika activities, with EC₅₀ values of 30.86 µM for MR766 and 46.23 µM for HPF2013. The mechanism of action was investigated using specific antiviral assays, and it was demonstrated that ellagic acid was primarily active as it prevented Zika virus infection and was able to significantly reduce Zika virus progeny production. Our data demonstrate the anti-Zika activity of pomegranate leaf extract and ellagic acid for the first time. These findings identify ellagic acid as a possible anti-Zika candidate compound that can be used for preventive and therapeutic interventions.

Anti-Zika virus and anti-Usutu virus activity of human milk and its components

The benefits of human milk are mediated by multiple nutritional, trophic, and immunological components, able to promote infant's growth, maturation of its immature gut, and to confer protection against infections. Despite these widely recognized properties, breast-feeding represents an important mother-to-child transmission route of some viral infections. Different studies show that some flaviviruses can occasionally be detected in breast milk, but their transmission to the newborn is still controversial. The aim of this study is to investigate the antiviral activity of human milk (HM) in its different stages of maturation against two emerging flaviviruses, namely Zika virus (ZIKV) and Usutu virus (USUV) and to verify whether HM-derived extracellular vesicles (EVs) and glycosaminoglycans (GAGs) contribute to the milk protective effect. Colostrum, transitional and mature milk samples were collected from 39 healthy donors. The aqueous fractions were tested in vitro with specific antiviral assays and EVs and GAGs were derived and characterized. HM showed antiviral activity against ZIKV and USUV at all the stages of lactation with no significant differences in the activity of colostrum, transitional or mature milk. Mechanism of action studies demonstrated that colostrum does not inactivate viral particles, but it hampers the binding of both flaviviruses to cells. We also demonstrated that HM-EVs and HM-GAGs contribute, at least in part, to the anti-ZIKV and anti-USUV action of HM. This study discloses the intrinsic antiviral activity of HM against ZIKV and USUV and demonstrates the contribution of two bioactive components in mediating its protective effect. Since the potential infectivity of HM during ZIKV and USUV infection is still unclear, these data support the World Health Organization recommendations about breast-feeding during ZIKV infection and could contribute to producing new guidelines for a possible USUV epidemic.

The cholesterol metabolite 27-hydroxycholesterol inhibits SARS-CoV-2 and is markedly decreased in COVID-19 patients

There is an urgent need to identify antivirals against the coronavirus SARS-CoV-2 in the current COVID-19 pandemic and to contain future similar emergencies early on. Specific side-chain cholesterol oxidation products of the oxysterols family have been shown to inhibit a large variety of both enveloped and non-enveloped human viral pathogens. Here we report on the in vitro inhibitory activity of the redox active oxysterol 27-hydroxycholesterol against SARS-CoV-2 and against one of the common cold agents HCoV-OC43 human coronavirus without significant cytotoxicity. Interestingly, physiological serum levels of 27-hydroxycholesterol in SARS-CoV-2 positive subjects were significantly decreased compared to the matched control group, reaching a marked 50% reduction in severe COVID-19 cases. Moreover, no correlation at all was observed between 24-hydroxycholesterol and 25-hydroxycholesterol serum levels and the severity of the disease. Opposite to that of 27-hydroxycholesterol was the behaviour of two recognized markers of redox imbalance, i.e. 7-ketocholesterol and 7β-hydroxycholesterol, whose serum levels were significantly increased especially in severe COVID-19. The exogenous administration of 27-hydroxycholesterol may represent in the near future a valid antiviral strategy in the worsening of diseases caused by present and emerging coronaviruses.

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27-hydroxycholesterol (27OHC) inhibits the replication of SARS-CoV-2 by interfering with its entry into target cells.

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The broad antiviral effect of 27OHC is also exerted against another β-coronavirus, HCoV-OC43.

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Blood levels of 27OHC were decreased in SARS-CoV-2 infected individuals, especially in patients with severe COVID-19.

•

COVID-19 patients showed increased serum levels of 7-ketocholesterol and 7β-hydroxycholesterol, markers of oxidative stress.

Extracellular Vesicles in Human Preterm Colostrum Inhibit Infection by Human Cytomegalovirus In Vitro

Breast milk is a complex biofluid that nourishes infants, supports their growth and protects them from diseases. However, at the same time, breastfeeding is a transmission route for human cytomegalovirus (HCMV), with preterm infants being at a great risk of congenital disease. The discrepancy between high HCMV transmission rates and the few reported cases of infants with severe clinical illness is likely due to the protective effect of breast milk. The aim of this study was to investigate the anti-HCMV activity of human preterm colostrum and clarify the role of colostrum-derived extracellular vesicles (EVs). Preterm colostrum samples were collected and the EVs were purified and characterized. The in vitro anti-HCMV activity of both colostrum and EVs was tested against HCMV, and the viral replication step inhibited by colostrum-purified EVs was examined. We investigated the putative role EV surface proteins play in impairing HCMV infection using shaving experiments and proteomic analysis. The obtained results confirmed the antiviral action of colostrum against HCMV and demonstrated a remarkable antiviral activity of colostrum-derived EVs. Furthermore, we demonstrated that EVs impair the attachment of HCMV to cells, with EV surface proteins playing a role in mediating this action. These findings contribute to clarifying the mechanisms that underlie the protective role of human colostrum against HCMV infection.

Antiviral Activity of a Arisaema Tortuosum Leaf Extract and Some of its Constituents against Herpes Simplex Virus Type 2

Infections caused by HSV-2 are a public health concern worldwide, and there is still a great demand for the discovery of novel anti-herpes virus agents effective against strains resistant to current antiviral agents. In this context, medicinal plants represent an alternative source of active compounds for developing efficient antiviral therapies. The aim of this study was to evaluate the antiviral activity of Arisaema tortuosum, a plant used in the traditional medicine of India. A chloroform soluble fraction of the leaves exhibited anti-HSV-2 activity with a selectivity index of 758. The extract was also active against acyclovir-resistant HSV-2 and HSV-1. The mechanism of action of the extract was investigated evidencing inhibition of both early and late events of the HSV-2 replicative cycle. A HPLC-PDA-MS/MS analysis showed the presence of flavonoids including apigenin and luteolin in the chloroform extract (CE). Apigenin and luteolin showed a high inhibitory activity with EC₅₀ values of 0.05 and 0.41 µg/mL, respectively. Both compounds exhibited antiviral activity when added up to 6 h post infection and were able to reduce the viral progeny production. In addition, apigenin interfered with cell-to-cell virus spread.

Modulation of cell proteome by 25-hydroxycholesterol and 27-hydroxycholesterol: A link between cholesterol metabolism and antiviral defense

Physiological cholesterol metabolism implies the generation of a series of oxidized derivatives, whose oxysterols are by far the most investigated ones for their potential multifaceted involvement in human pathophysiology. In this regard, noteworthy is the broad antiviral activity displayed by defined side chain oxysterols, in particular 25-hydroxycholesterol (25HC) and 27-hydroxycholesterol (27HC). Although their antiviral mechanism(s) may vary depending on virus/host interaction, these oxysterols share the common feature to hamper viral replication by interacting with cellular proteins. Here reported is the first analysis of the modulation of a cell proteome by these two oxysterols, that, besides yielding additional clues about their potential involvement in the regulation of sterol metabolism, provides novelinsights about the mechanism underlying the inhibition of virus entry and trafficking within infected cells. We show here that both 25HC and 27HC can down-regulate the junction adhesion molecule-A (JAM-A) and the cation independent isoform of mannose-6-phosphate receptor (MPRci), two crucial molecules for the replication of all those viruses that exploit adhesion molecules and the endosomal pathway to enter and diffuse within target cells.

Detection of SARS-CoV-2 in Milk From COVID-19 Positive Mothers and Follow-Up of Their Infants

Background: In the current SARS-Coronavirus-2 (SARS-CoV-2) pandemic little is known about SARS-CoV-2 in human milk. It is important to discover if breast milk is a vehicle of infection. Objective: Our aim was to look for the presence of SARS-CoV-2 RNA in the milk of a group of SARS-CoV-2 positive mothers from North-West Italy. Methods: This is a prospective collaborative observational study where samples of human milk from 14 breastfeeding mothers positive for SARS-CoV-2 were collected. A search of viral RNA in breast milk samples was performed by RT-PCR (Real-Time reverse-transcriptase-Polymerase-Chain-Reaction) methodology tested for human milk. All the newborns underwent a clinical follow up during the first month of life or until the finding of two sequential negative swabs. Results: In 13 cases the search for SARS-CoV-2 RNA in milk samples resulted negative and in one case it was positive. Thirteen of the 14 newborns were exclusively breastfed and closely monitored in the first month of life. Clinical outcome was uneventful. Four newborns tested positive for SARS-CoV-2 and were all detected in the first 48 h of life, after the onset of maternal symptoms. Also the clinical course of these 4 infants, including the one who received mother's milk positive for SARS-CoV-2, was uneventful, and all of them became SARS-CoV-2 negative within 6 weeks of life. Conclusion: Our study supports the view that SARS-CoV-2 positive mothers do not expose their newborns to an additional risk of infection by breastfeeding.

Antiviral oxysterols are present in human milk at diverse stages of lactation

Oxysterols are cholesterol oxidation derivatives. Those containing an additional hydroxyl group on the side chain of the cholesterol molecule result from a physiological enzymatic synthesis and include the majority of oxysterols present in the circulation. Among these, 25-hydroxycholesterol (25OHC) and 27-hydroxycholesterol (27OHC) are characterized by a broad antiviral activity and are now considered involved in the innate immune response against viruses. Despite the emerging role of these sterols in the innate antiviral defences, no data are available on their presence in human breast milk (BM) to date. In this study, we investigated the content of oxysterols of enzymatic synthesis in BM of twelve donor mothers at different stages of lactation (i.e. in colostrum, transitional milk, and mature milk) by gas chromatography-mass spectrometry analysis. The side-chain oxysterols 25OHC, 27OHC, and 24S-hydroxycholesterol (24SOHC) were actually present in BM in all stages of lactation, but the concentration of 27OHC showed a remarkable peak in colostrum. Antiviral assays revealed that all the colostrum samples contained 27OHC concentrations that were active in vitro against two relevant pediatric viral pathogens: the human rotavirus and the human rhinovirus. Overall, this study discloses new antiviral components of BM and suggests a passive transfer of these protective factors to the infant via breastfeeding, especially in the first few days of lactation.

Colostrum from cows immunized with a veterinary vaccine against bovine rotavirus displays enhanced in vitro anti-human rotavirus activity

Human rotaviruses represent a major cause of severe diarrheal disease in infants and young children. The limited impact of oral vaccines on global estimates of rotavirus mortality and the suboptimal use of oral rehydration justify the need for alternative prophylactic and therapeutic strategies, especially for immunocompromised hosts. The protective effects of colostrum-the first milk produced during the initial 24 to 48 h after parturition-are well documented in the literature. In particular, the ingestion of hyperimmune bovine colostrum has been proposed as an alternative preventive approach against human rotavirus gastroenteritis. Although the immunization of pregnant cows with human rotavirus boosts the release of specific immunoglobulin G in bovine colostrum, it raises regulatory and safety issues. In this study, we demonstrated that the conventional bovine rotavirus vaccine is sufficient to enhance the anti-human rotavirus protective efficacy of bovine colostrum, thus providing a conservative approach to produce hyperimmune bovine colostrum, making it exploitable as a functional food.

Effect of different non-conventional extraction methods on the antibacterial and antiviral activity of fucoidans extracted from Nizamuddinia zanardinii

In the current study, fucoidans from brown alga Nizamuddinia zanardinii were isolated with conventional and non-conventional extraction procedures to evaluate the effects of recently introduced technologies on biochemical characteristics and saccharide composition of the extracts, along with their antibacterial, antiviral and cytotoxic properties. The results demonstrated that subcritical water extraction showed the highest fucoidans yield (13.15%), while the lowest yield was obtained using ultrasound extraction method (3.6%). The polysaccharide chains consisted of fucose, galactose, glucose, mannose and xylose, whose molar percentages differed according to the extraction method used. The weight mean average molecular weight of fucoidans varied between 444 and 1184 kDa. The FT-IR spectroscopy confirmed the presence of sulfate esters by bending vibration of COS and stretching vibration of SO peaks at 818 and 1250 cm-1, respectively. Antibacterial assays showed that microwave- and subcritical water-extracted fucoidans inhibited the growth of E.coli and that enzyme-ultrasound, ultrasound-microwave and subcritical water extracted fucoidans exhibited inhibitory effects against P. aeruginosa at 2 mg/mL. Antiviral studies revealed that all the extracted fucoidans exerted strong antiviral activity against HSV-2 infection, with EC50 values in the 0.027-0.123 μg/mL range; indeed the viscozyme-extracted macromolecules displayed the best selectivity index.

Processing of Donor Human Milk: Update and Recommendations From the European Milk Bank Association (EMBA)

Background: A mother's own milk (MOM) is the gold standard for the feeding and nutrition of preterm and full term infants. When MOM is not available or there is not enough, donor human milk (DHM) should be used. Milk delivered to Human Milk Banks (HMBs) should be pasteurized to inactivate viral and bacterial agents. Currently, a pasteurization process at 62.5°C for 30 min (Holder pasteurization, HoP) is recommended in all international HMBs guidelines. State of the art: It is known that HoP affects some of the nutritional and biological components of human milk. Studies have demonstrated that temperature cycle in HoP is not always controlled or calibrated. A better check of these parameters in the pasteurizers on the market today may contribute to an improvement of the quality of HM, still maintaining some of the negative effects of the heat treatment of human milk. So, food industry, and dairy industry in particular, are evaluating innovative methodologies alternative to HoP to better preserve the nutritional and biological properties of fresh human milk, while assuring at least the same microbiological safety of HoP. The most studied processing techniques include High-Temperature-Short-Time (HTST) pasteurization, High Pressure Processing (HPP), and Ultraviolet-C (UV-C) irradiation. HTST is a thermal process in which milk is forced between plates or pipes that are heated on the outside by hot water at a temperature of 72°C for 5-15 s. HPP is a non-thermal processing method that can be applied to solid and liquid foods. This technology inactivates pathogenic microorganisms by applying a high hydrostatic pressure (usually 300-800 MPa) during short-term treatments (<5-10 min). UV irradiation utilizes short-wavelength ultraviolet radiation in the UV-C region (200-280 nm), which is harmful to microorganisms. It is effective in destroying the nucleic acids in these organisms, so that their DNA is disrupted by UV radiation. Aim: The aim of this paper is to present the EMBA recommendations on processing of HM, based on the most recent results obtained with these new technologies. Conclusions: Although research on the most promising technologies that will represent an alternative to HoP (HTST, HPP, UV-C) in the future is progressing, it is now important to recognize that the consistency and quality assurance of the pasteurizers on the market today represent a fundamental component that was previously lacking in the Holder approach.

Anti-zika virus activity of polyoxometalates

Zika virus (ZIKV) is an emerging infectious viral pathogen associated with severe fetal cerebral anomalies and the paralytic Guillain-Barrè syndrome in adults. It was the cause of a recent global health crisis following its entrance into a naïve population in the Americas. Nowadays, no vaccine or specific antiviral against ZIKV is available. In this study, we identified three polyoxometalates (POMs), the Anderson-Evans type [TeW₆O₂₄]^6- (TeW₆), and the Keggin-type [TiW₁₁CoO₄₀]^8-_ (TiW₁₁Co), and [Ti₂PW₁₀O₄₀]^7- (Ti₂PW₁₀), that inhibit ZIKV infection with EC₅₀s in the low micromolar range. Ti₂PW₁₀, the POM with the greatest selectivity index (SI), was selected and the step of ZIKV replicative cycle putatively inhibited was investigated by specific antiviral assays. We demonstrated that Ti₂PW₁₀ targets the entry process of ZIKV infection and it is able to significantly reduce ZIKV progeny production. These results suggest that the polyanion Ti₂PW₁₀ could be a good starting point to develop an effective therapeutic to treat ZIKV infection.

Novel broad spectrum virucidal molecules against enveloped viruses

Viral infections are an important cause of death worldwide. Unfortunately, there is still a lack of antiviral drugs or vaccines for a large number of viruses, and this represents a remarkable challenge particularly for emerging and re-emerging viruses. For this reason, the identification of broad spectrum antiviral compounds provides a valuable opportunity for developing efficient antiviral therapies. Here we report on a class of rhodanine and thiobarbituric derivatives displaying a broad spectrum antiviral activity against seven different enveloped viruses including an HSV-2 acyclovir resistant strain with favorable selectivity indexes. Due to their selective action on enveloped viruses and to their lipid oxidation ability, we hypothesize a mechanism on the viral envelope that affects the fluidity of the lipid bilayer, thus compromising the efficiency of virus-cell fusion and preventing viral entry.

25-Hydroxycholesterol and 27-hydroxycholesterol inhibit human rotavirus infection by sequestering viral particles into late endosomes

A novel innate immune strategy, involving specific cholesterol oxidation products as effectors, has begun to reveal connections between cholesterol metabolism and immune response against viral infections. Indeed, 25-hydroxycholesterol (25HC) and 27-hydroxycholesterol (27HC), physiologically produced by enzymatic oxidation of cholesterol, act as inhibitors of a wide spectrum of enveloped and non-enveloped human viruses. However, the mechanisms underlying their protective effects against non-enveloped viruses are almost completely unexplored. To get insight into this field, we investigated the antiviral activity of 25HC and 27HC against a non-enveloped virus causing acute gastroenteritis in children, the human rotavirus (HRV). We found that 25HC and 27HC block the infectivity of several HRV strains at 50% inhibitory concentrations in the low micromolar range in the absence of cell toxicity. Both molecules affect the final step of virus penetration into cells by preventing the association of two cellular proteins: the oxysterol binding protein (OSBP) and the vesicle-associated membrane protein-associated protein-A (VAP-A). By altering the activity of these cellular mediators, 25HC and 27HC disturb the recycling of cholesterol between the endoplasmic reticulum and the late endosomes which are exploited by HRV to penetrate into the cell. The substantial accumulation of cholesterol in the late endosomal compartment results in sequestering viral particles inside these vesicles thereby preventing cytoplasmic virus replication. These findings suggest that cholesterol oxidation products of enzymatic origin might be primary effectors of host restriction strategies to counteract HRV infection and point to redox active lipids involvement in viral infections as a research area of focus to better focus in order to identify novel antiviral agents targets.

Rhodanine derivatives as potent anti-HIV and anti-HSV microbicides

Although highly active antiretroviral therapies (HAART) remarkably increased life expectancy of HIV positive people, the rate of novel HIV-1 infections worldwide still represent a major concern. In this context, pre-exposure prophylaxis (PrEP) approaches such as vaginal microbicide gels topically releasing antiretroviral drugs, showed to have a striking impact in limiting HIV-1 spread. Nevertheless, the co-presence of other genital infections, particularly those due to HSV-1 or 2, constitute a serious drawback that strongly limits the efficacy of PrEP approaches. For this reason, combinations of different compounds with mixed antiviral and antiretroviral activity are thoroughly investigated Here we report the synthesis and the biological evaluation of a novel series of rhodanine derivatives, which showed to inhibit both HIV-1 and HSV-1/2 replication at nanomolar concentration, and were found to be active also on acyclovir resistant HSV-2 strains. The compounds showed a considerable reduction of activity in presence of serum due to a high binding to serum albumin, as determined through in vitro ADME evaluations. However, the most promising compound of the series maintained a considerable activity in gel formulation, with an EC50 comparable to that obtained for the reference drug tenofovir. Moreover, the series of compounds showed pharmacokinetic properties suitable for topical formulation, thus suggesting that the novel rhodanine derivatives could represent effective agents to be used as dual anti HIV/HSV microbicides in PrEP approaches.

The traditional use of Vachellia nilotica for sexually transmitted diseases is substantiated by the antiviral activity of its bark extract against sexually transmitted viruses

ETHNOPHARMACOLOGICAL RELEVANCE

Vachellia (Acacia) nilotica and other plants of this genus have been used in traditional medicine of Asian and African countries to treat many disorders, including sexually transmitted diseases, but few studies were performed to validate their anti-microbial and anti-viral activity against sexually transmitted infections.

AIM OF THE STUDY

The present study was undertaken to explore whether the ethnomedical use of V.nilotica to treat genital lesions is substantiated by its antiviral activity against the human immunodeficiency virus (HIV), the herpes simplex virus (HSV) and the human papillomavirus (HPV).

MATERIALS AND METHODS

The antiviral activity of V.nilotica was tested in vitro by virus-specific inhibition assays using HSV-2 strains, sensible or resistant to acyclovir, HIV-1IIIb strain and HPV-16 pseudovirion (PsV). The potential mode of action of extract against HSV-2 and HPV-16 was further investigated by virus inactivation and time-of-addition assays on cell cultures.

RESULTS

V.nilotica chloroform, methanolic and water bark extracts exerted antiviral activity against HSV-2 and HPV-16 PsV infections; among these, methanolic extract showed the best EC50s with values of 4.71 and 1.80µg/ml against HSV-2 and HPV-16, respectively, and it was also active against an acyclovir-resistant HSV-2 strain with an EC50 of 6.71µg/ml. By contrast, no suppression of HIV infection was observed. Investigation of the mechanism of action revealed that the methanolic extract directly inactivated the infectivity of the HPV-16 particles, whereas a partial virus inactivation and interference with virus attachment (EC50 of 2.74µg/ml) were both found to contribute to the anti-HSV-2 activity.

CONCLUSIONS

These results support the traditional use of V.nilotica applied externally for the treatment of genital lesions. Further work remains to be done in order to identify the bioactive components.

Broad-spectrum non-toxic antiviral nanoparticles with a virucidal inhibition mechanism

Viral infections kill millions yearly. Available antiviral drugs are virus-specific and active against a limited panel of human pathogens. There are broad-spectrum substances that prevent the first step of virus-cell interaction by mimicking heparan sulfate proteoglycans (HSPG), the highly conserved target of viral attachment ligands (VALs). The reversible binding mechanism prevents their use as a drug, because, upon dilution, the inhibition is lost. Known VALs are made of closely packed repeating units, but the aforementioned substances are able to bind only a few of them. We designed antiviral nanoparticles with long and flexible linkers mimicking HSPG, allowing for effective viral association with a binding that we simulate to be strong and multivalent to the VAL repeating units, generating forces (∼190 pN) that eventually lead to irreversible viral deformation. Virucidal assays, electron microscopy images, and molecular dynamics simulations support the proposed mechanism.  These particles show no cytotoxicity, and in vitro nanomolar irreversible activity against herpes simplex virus (HSV), human papilloma virus, respiratory syncytial virus (RSV), dengue and lenti virus. They are active ex vivo in human cervicovaginal histocultures infected by HSV-2 and in vivo in mice infected with RSV.