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Adenoviral infections, particularly in children, remain a significant public health issue with no approved targeted treatments. Artemisinin and its derivatives, well-known for their use in malaria treatment, have shown antiviral activities in recent studies. However, their efficacy against human adenovirus (HAdV) remains unexplored. This study aimed to assess the activity of artemisinin and its derivatives against HAdV infection in vitro using cell lines and primary cells. Our data revealed that artemisinin exhibited dose-dependent anti-HAdV activity with no apparent cytotoxicity over a wide concentration range. Mechanistically, artemisinin did not affect viral attachment or entry into target cells, nor the viral genome entry into cell nucleus. Instead, it inhibited HAdV through suppression of viral DNA replication. Comparative analysis with its derivatives, artesunate and artemisone, showed distinct cytotoxicity and anti-adenoviral profiles, with artemisone showing superior efficacy and lower toxicity. Further validation using a primary airway epithelial cell model confirmed the anti-adenoviral activity of both artemisinin and artemisone against different virus strains. Together, our findings suggest that artemisinin and its derivatives may be promising candidates for anti-HAdV treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Human adenovirus (HADV) infection can pose a serious threat to children, leading to a variety of respiratory illnesses and other complications. Particularly, children with weak immune systems are vulnerable to severe adenovirus infections with high mortality. The main focus of this study is to propose new antiviral agents as lead HADV inhibitors for children. So, several antiviral agents used in children were subjected to finding new HADV inhibitors using important computational methods of molecular docking, molecular dynamics (MD) simulation, Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) binding free energy calculations, density functional theory (DFT), and pharmacokinetic analysis. Molecular docking of standard cidofovir along with other ligands, suggested that sofosbuvir has the highest binding energy (-10.8 kcal/mol), followed by baloxavir marboxil (-10.36 kcal/mol). Further, the analysis of molecular interactions using MD simulation (100 ns) and MM-PBSA indicated that baloxavir marboxil has formed the most stable protein-ligand complex with HADV, followed by sofosbuvir. The binding free energies of baloxavir marboxil and sofosbuvir were found to be -61.724 kJ/mol and -48.123 kJ/mol, respectively. The DFT and drug-likeness properties of these compounds were also investigated. Overall, two antiviral agents, such as baloxavir marboxil, and sofosbuvir are suggested as lead repurposed candidates against HADV.Communicated by Ramaswamy H. Sarma.

Background: Non-enveloped viruses, which lack a lipid envelope, display higher resistance to disinfectants, soaps and sanitizers compared to enveloped viruses. The capsids of these viruses are highly stable and symmetric protein shells that resist inactivation by commonly employed virucidal agents. This group of viruses include highly transmissible human pathogens such as Rotavirus, Poliovirus, Foot and Mouth Disease Virus, Norovirus and Adenovirus; thus, devising appropriate strategies for chemical disinfection is essential., Results: In this study, we tested a mild, hypoallergenic combination of a denaturant, alcohol, and organic acid (3.2% citric acid, 1% urea and 70% ethanol, pH4) on two representative non-enveloped viruses - Human Adenovirus 5 (HAdV5) and Feline Calicivirus (FCV)- and evaluated the pathways of capsid neutralization using biophysical methods. The conformational shifts in the capsid upon chemical treatment were studied using Differential Scanning Calorimetry (DSC), while the morphological alterations were visualized concurrently using Transmission Electron Microscopy (TEM). We found that while treatment of purified HAdV5 particles with a formulation resulted in thermal instability and, large scale aggregation; similar treatment of FCV particles resulted in complete collapse of the capsids. Further, while individual components of the formulation caused significant damage to the capsids, a synergistic action of the whole formulation was evident against both non-enveloped viruses tested., Conclusions: The distinct effects of the chemical treatment on the morphology of HAdV5 and FCV suggests that non-enveloped viruses with icosahedral geometry can follow different morphological pathways to inactivation. Synergistic effect of whole formulation is more effective compared to individual components. Molecular level understanding of inactivation pathways may result in the design and development of effective mass-market formulations for rapid neutralization of non-enveloped viruses., (© 2024. The Author(s).)

Human adenoviruses can cause serious, disseminated infections in immunocompromised patients. For pediatric allogeneic stem cell transplant patients, the case fatality rate can reach 80%. Still, there is no available antiviral drug that is specifically approved by the Food and Drug Administration for the treatment of adenovirus infections. To fill this pressing medical need, we have developed NPP-669, a prodrug of cidofovir with broad activity against double-stranded DNA viruses, including adenoviruses. Here, we report on the in vivo anti-adenoviral efficacy of NPP-669. Using the immunosuppressed Syrian hamster as the model, we show that NPP-669 is highly efficacious when dosed orally at 1 mg/kg and 3 mg/kg. In a delayed administration experiment, NPP-669 was more effective than brincidofovir, a similar compound that reached Phase III clinical trials. Furthermore, parenteral administration of NPP-669 increased its efficacy approximately 10-fold compared to oral dosing without apparent toxicity, suggesting that this route may be preferable in a hospital setting. Based on these findings, we believe that NPP-669 is a promising new compound that needs to be further investigated., Competing Interests: The authors declare no conflict of interest.

Removal of pathogenic viruses from water resources is critically important for sanitation and public health. Nanotechnology is a promising technology for virus inactivation. In this paper, the effects of titanium dioxide (TiO 2 ) anatase nanoparticles (NPs) on human adenovirus type 35 (HAdV-35) removal under static and dynamic (with agitation) batch conditions were comprehensively studied. Batch experiments were performed at room temperature (25 °C) with and without ambient light using three different initial virus concentrations. The virus inactivation experimental data were satisfactorily fitted with a pseudo-first-order expression with a time-dependent rate coefficient. The experimental results demonstrated that HAdV-35 sorption onto TiO 2 NPs was favored with agitation under both ambient light and dark conditions. However, no distinct relationships between virus initial concentration and removal efficiency could be established from the experimental data., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Ferrate (Fe(VI): HFeO 4 - /FeO 4 2- ), a potent oxidant, has been investigated as an alternative chemical disinfectant in water treatment due to its reduced production of disinfection by-products. In this study, we assessed the disinfecting ability of potassium ferrate against a variety of microorganisms, including waterborne pathogens, under varying pH and water temperature conditions. We presented CT values, a metric of ferrate concentrations (C) and contact time (T), to quantify microbial inactivation rates. Among the tested microorganisms, human adenovirus was the least resistant to ferrate, followed by waterborne bacteria such as Escherichia coli and Vibrio cholerae , and finally, the protozoan parasite Giardia duodenalis . We further investigated the impact of two pH values (7 and 8) and two temperatures (5 and 25 °C) on microbial inactivation rates, observing that inactivation rates increased with lower pH and higher temperature. In addition to showcasing ferrate's capacity to effectively inactivate a range of the tested microorganisms, we offer a ferrate CT table to facilitate the comparison of the effectiveness of various disinfection methods., Competing Interests: The authors declare there is no conflict., (© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).)

Human adenovirus (HAdV) and cytomegalovirus (HCMV) cause high morbidity and mortality in patients undergoing solid organ transplantation (SOT) and haematopoietic stem cell transplantation (HSCT). Immunosuppressors are used universally to prevent graft-vs-host disease in HSCT and graft rejection in SOT. The long-term use of these drugs is associated with a high risk of infection, but there is also evidence of their specific interference with viral infection. This study evaluated the antiviral activity of immunosuppressors commonly used in clinical practice in SOT and HSCT recipients in vitro to determine whether their use could be associated with reduced risk of HAdV and HCMV infection. Cyclophosphamide, tacrolimus, cyclosporine, mycophenolic acid, methotrexate, everolimus and sirolimus presented antiviral activity, with 50% inhibitory concentration (IC 50 ) values at low micromolar and sub-micromolar concentrations. Mycophenolic acid and methotrexate showed the greatest antiviral effects against HAdV (IC 50 =0.05 µM and 0.3 µM, respectively) and HCMV (IC 50 =10.8 µM and 0.02 µM, respectively). The combination of tacrolimus and mycophenolic acid showed strong synergistic antiviral activity against both viruses, with combinatory indexes (CI 50 ) of 0.02 and 0.25, respectively. Additionally, mycophenolic acid plus cyclosporine, and mycophenolic acid plus everolimus/sirolimus showed synergistic antiviral activity against HAdV (CI 50 =0.05 and 0.09, respectively), while methotrexate plus cyclosporine showed synergistic antiviral activity against HCMV (CI 50 =0.29). These results, showing antiviral activity in vitro against both HAdV and HCMV, at concentrations below the human C max values, may be relevant for the selection of specific immunosuppressant therapies in patients at risk of HAdV and HCMV infections., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Human adenovirus (HAdV) infection is a major cause of respiratory disease, yet no antiviral drugs have been approved for its treatment. Herein, we evaluated the antiviral and anti-inflammatory effects of cyclin-dependent protein kinase (CDK) inhibitor indirubin-3'-monoxime (IM) against HAdV infection in cells and a transgenic mouse model. After evaluating its cytotoxicity, cytopathic effect reduction, antiviral replication kinetics, and viral yield reduction assays were performed to assess the anti-HAdV activity of IM. Quantitative real-time polymerase chain reaction (qPCR), quantitative reverse transcription PCR (qRT-PCR), and western blotting were used to assess the effects of IM on HAdV DNA replication, transcription, and protein expression, respectively. IM significantly inhibited HAdV DNA replication as well as E1A and Hexon transcription, in addition to significantly suppressing the phosphorylation of the RNA polymerase II C-terminal domain (CTD). IM mitigated body weight loss, reduced viral burden, and lung injury, decreasing cytokine and chemokine secretion to a greater extent than cidofovir. Altogether, IM inhibits HAdV replication by downregulating CTD phosphorylation to suppress viral infection and corresponding innate immune reactions as a promising therapeutic agent., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy which shows unparalleled therapeutic resistance due to its genetic and cellular heterogeneity, dense stromal tissue, and immune-suppressive tumour microenvironment. Oncolytic virotherapy has emerged as a new treatment modality which uses tumour-specific viruses to eliminate cancerous cells. Non-human primate adenoviruses of the human adenovirus B (HAdV-B) species have demonstrated considerable lytic potential in human cancer cells as well as limited preexisting neutralizing immunity in humans. Previously, we have generated a new oncolytic derivative of the gorilla-derived HAdV-B AdV-lumc007 named 'GoraVir'. Here, we show that GoraVir displays oncolytic efficacy in pancreatic cancer cells and pancreatic-cancer-associated fibroblasts. Moreover, it retains its lytic potential in monoculture and co-culture spheroids. In addition, we established the ubiquitously expressed complement receptor CD46 as the main entry receptor for GoraVir. Finally, a single intratumoural dose of GoraVir was shown to delay tumour growth in a BxPC-3 xenograft model at 10 days post-treatment. Collectively, these data demonstrate that the new gorilla-derived oncolytic adenovirus is a potent oncolytic vector candidate that targets both pancreatic cancer cells and tumour-adjacent stroma., (© 2023 The Authors. Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Differentiated HepaRG cells are popular in vitro cell models for hepatotoxicity studies. Their differentiation is usually supported by the addition of dimethyl sulfoxide (DMSO), an amphipathic solvent widely used in biomedicine, for example, in potential novel therapeutic drugs and cryopreservation of oocytes. Recent studies have demonstrated drastic effects, especially on epigenetics and extracellular matrix composition, induced by DMSO, making its postulated inert character doubtful. In this work, the influence of DMSO and DMSO-mediated modulation of differentiation on human adenovirus (HAdV) infection of HepaRG cells was investigated. We observed an increase in infectivity of HepaRG cells by HAdVs in the presence of 1% DMSO. However, this effect was dependent on the type of medium used for cell cultivation, as cells in William's E medium showed significantly stronger effects compared with those cultivated in DMEM. Using different DMSO concentrations, we proved that the impact of DMSO on infectability was dose-dependent. Infection of cells with a replication-deficient HAdV type demonstrated that the mode of action of DMSO was based on viral entry rather than on viral replication. Taken together, these results highlight the strong influence of the used cell-culture medium on the performed experiments as well as the impact of DMSO on infectivity of HepaRG cells by HAdVs. As this solvent is widely used in cell culture, those effects must be considered, especially in screening of new antiviral compounds.

Viral proteases are indispensable for successful virion maturation, thus making them a prominent drug target. Their enzyme activity is tightly spatiotemporally regulated by expression in the precursor form with little or no activity, followed by activation via autoprocessing. These cleavage events are frequently triggered upon transportation to a specific compartment inside the host cell. Typically, precursor oligomerization or the presence of a co-factor is needed for activation. A detailed understanding of these mechanisms will allow ligands with non-canonical mechanisms of action to be designed, which would specifically modulate the initial irreversible steps of viral protease autoactivation. Binding sites exclusive to the precursor, including binding sites beyond the protease domain, can be exploited. Both inhibition and up-regulation of the proteolytic activity of viral proteases can be detrimental for the virus. All these possibilities are discussed using examples of medically relevant viruses including herpesviruses, adenoviruses, retroviruses, picornaviruses, caliciviruses, togaviruses, flaviviruses, and coronaviruses.

Previous studies reported on the broad-spectrum antiviral function of heparin. Here we investigated the antiviral function of magnesium-modified heparin and found that modified heparin displayed a significantly enhanced antiviral function against human adenovirus (HAdV) in immortalized and primary cells. Nuclear magnetic resonance analyses revealed a conformational change of heparin when complexed with magnesium. To broadly explore this discovery, we tested the antiviral function of modified heparin against herpes simplex virus type 1 (HSV-1) and found that the replication of HSV-1 was even further decreased compared to aciclovir. Moreover, we investigated the antiviral effect against the new severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and measured a 55-fold decreased viral load in the supernatant of infected cells associated with a 38-fold decrease in virus growth. The advantage of our modified heparin is an increased antiviral effect compared to regular heparin.

Type III interferons (lambda IFNs) are a quite new, small family of three closely related cytokines with interferon-like activity. Attention to IFN-λ is mainly focused on direct antiviral activity in which, as with IFN-α, viral genome replication is inhibited without the participation of immune system cells. The heterodimeric receptor for lambda interferons is exposed mainly on epithelial cells, which limits its possible action on other cells, thus reducing the likelihood of developing undesirable side effects compared to type I IFN. In this study, we examined the antiviral potential of exogenous human IFN-λ1 in cellular models of viral infection. To study the protective effects of IFN-λ1, three administration schemes were used: 'preventive' (pretreatment); 'preventive/therapeutic' (pre/post); and 'therapeutic' (post). Three IFN-λ1 concentrations (from 10 to 500 ng/mL) were used. We have shown that human IFN-λ1 restricts SARS-CoV-2 replication in Vero cells with all three treatment schemes. In addition, we have shown a decrease in the viral loads of CHIKV and IVA with the 'preventive' and 'preventive/therapeutic' regimes. No significant antiviral effect of IFN-λ1 against AdV was detected. Our study highlights the potential for using IFN-λ as a broad-spectrum therapeutic agent against respiratory RNA viruses.

There is no approved antiviral therapy for adenovirus (HAdV) ocular infections. Astodrimer sodium (SPL7013) is a polyanionic dendrimer with antiviral activity. The current study evaluated the ocular tolerability and anti-adenoviral efficacy of topical SPL7013 in rabbit ocular models. In a tolerability study, rabbits were treated with 3% SPL7013, vehicle, or 0.5% cidofovir. Their eyes were graded using the Draize scale. In antiviral efficacy studies, HAdV5 inoculated eyes were treated with 3% SPL7013, vehicle, or 0.5% cidofovir. Eyes were cultured for the virus on days 0, 1, 3, 4, 5, 7, 9, 11, and 14. Viral titers were determined. There were no differences in Draize scores between 3% SPL7013 and vehicle on any day. Cidofovir produced significantly higher Draize scores on day 12 than SPL7013 and vehicle. The 3% SPL7013 and 0.5% cidofovir significantly reduced daily viral titers and positive cultures per total compared with vehicle on several different days. The 3% SPL7013 and 0.5% cidofovir significantly reduced the duration of HAdV5 shedding compared to vehicle. The 3% SPL7013 demonstrated significantly more antiviral activity compared with vehicle in the Ad5/NZW rabbit ocular model. The 3% SPL7013 induced "minimal" to "practically non-irritating" Draize scores in the ocular tolerability study. Further development of astodrimer sodium as a topical antiviral therapy for adenoviral ocular infections is indicated.

Human adenoviruses (HAdV) are ubiquitous human pathogens that cause a significant burden of respiratory, ocular, and gastrointestinal illnesses. Although HAdV infections are generally self-limiting, pediatric and immunocompromised individuals are at particular risk for developing severe disease. Currently, no approved antiviral therapies specific to HAdV exist. Recent outbreaks underscore the need for effective antiviral agents to treat life-threatening infections. In this review we will focus on recent developments in search of potential therapeutic agents for controlling HAdV infections, with a focus on those targeting post-entry stages of the virus replicative cycle., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Human adenovirus (HAdV) can cause severe disease in certain at-risk populations such as newborns, young children, the elderly and individuals with a compromised immune system. Unfortunately, no FDA-approved antiviraldrug is currently available for the treatment of HAdV infections. Within the nucleus of infected cells, the HAdV genome associates with histones and forms a chromatin-like structure during early infection, and viral gene expression appears to be regulated by cellular epigenetic processes. Thus, one potential therapeutic strategy to combat HAdV disease may be to target the cellular proteins involved in modifying the viral nucleoprotein structure and facilitating HAdV gene expression and replication. We have screened a panel of small molecules that modulate the activity of epigenetic regulatory proteins for compounds affecting HAdV gene expression. Several of the compounds, specifically chaetocin, gemcitabine and lestaurtinib, reduced HAdV recovery by 100- to 1000-fold, while showing limited effects on cell health, suggesting that these compounds may indeed be promising as anti-HAdV therapeutics., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purpose: The aim of this study was to test the antiviral effectivity of potassium peroxymonosulfate (RUBYSTA ® , KYORIN) against five epidemic keratoconjunctivitis-related types of Human adenovirus D in vitro., Methods: Five types of Human adenovirus D (8, 37, 53, 54 and 56) were incubated with 1% potassium peroxymonosulfate, 0.1% sodium hypochlorite (NaClO) or alcohol-based disinfectant for 30 s or 1 min. These solutions were subjected to measurements of viral titres by infection assays in A549 cells. At day 6 post-infection, both, supernatants and cells, were collected and the viral genome was assessed by real-time polymerase chain reaction analysis., Results: Treatments with 1% potassium peroxymonosulfate led to significant reduction in all tested Human adenovirus D types comparable to disinfecting effects by 0.1% NaClO. Overall, potassium peroxymonosulfate demonstrated sufficient inactivation of the major epidemic keratoconjunctivitis-causing Human adenovirus D to be considered for disinfection and prevention purposes in ophthalmological clinics and hospitals., Conclusion: This study demonstrated that potassium peroxymonosulfate is a promising disinfectant for the prevention of epidemic keratoconjunctivitis nosocomial infections in ophthalmological clinics.

Human adenoviruses (HAdVs) display a wide range of tissue tropism and can cause an array of symptoms from mild respiratory illnesses to disseminated and life-threatening infections in immunocompromised individuals. However, no antiviral drug has been approved specifically for the treatment of HAdV infections. Herein, we report our continued efforts to optimize salicylamide derivatives and discover compound 16 (JMX0493) as a potent inhibitor of HAdV infection. Compound 16 displays submicromolar IC 50 values, a higher selectivity index (SI > 100) and 2.5-fold virus yield reduction compared to our hit compound niclosamide. Moreover, unlike niclosamide, our mechanistic studies suggest that the antiviral activity of compound 16 against HAdV is achieved through the inhibition of viral particle escape from the endosome, which bars subsequent uncoating and the presentation of lytic protein VI.

An effective therapy for human adenovirus (HAdV) infections in immunocompromised patients and healthy individuals with community-acquired pneumonia remains an unmet medical need. We herein reported a series of novel substituted N -(4-amino-2-chlorophenyl)-5-chloro-2-hydroxybenzamide analogues as potent HAdV inhibitors. Compounds 6 , 15 , 29 , 40 , 43 , 46 , 47 , and 54 exhibited increased selectivity indexes (SI > 100) compared to the lead compound niclosamide, while maintaining sub-micromolar to low micromolar potency against HAdV. The preliminary mechanistic studies indicated that compounds 6 and 43 possibly target the HAdV DNA replication process, while compounds 46 and 47 suppress later steps of HAdV life cycle. Notably, among these derivatives, compound 15 showed improved anti-HAdV activity (IC 50 = 0.27 μM), significantly decreased cytotoxicity (CC 50 = 156.8 μM), and low in vivo toxicity (maximum tolerated dose = 150 mg/kg in hamster) as compared with niclosamide, supporting its further in vivo efficacy studies for the treatment of HAdV infections.

Coxsackievirus A24 variant (CVA24v) and human adenovirus 37 (HAdV-37) are leading causative agents of the severe and highly contagious ocular infections acute hemorrhagic conjunctivitis and epidemic keratoconjunctivitis, respectively. Currently, neither vaccines nor antiviral agents are available for treating these diseases, which affect millions of individuals worldwide. CVA24v and HAdV-37 utilize sialic acid as attachment receptors facilitating entry into host cells. Previously, we and others have shown that derivatives based on sialic acid are effective in preventing HAdV-37 binding and infection of cells. Here, we designed and synthesized novel pentavalent sialic acid conjugates and studied their inhibitory effect against CVA24v and HAdV-37 binding and infection of human corneal epithelial cells. The pentavalent conjugates are the first reported inhibitors of CVA24v infection and proved efficient in blocking HAdV-37 binding. Taken together, the pentavalent conjugates presented here form a basis for the development of general inhibitors of these highly contagious ocular pathogens.

Objectives: Human adenovirus (HAdV) infections are associated with a high morbidity and mortality in transplant patients requiring the use of antiviral treatments. Brincidofovir (BCV), a cytidine analog, inhibits HAdV replication through viral DNA elongation termination and likely through other mechanisms. To elucidate if BCV regulates cellular antiviral pathways, we analyzed its impact on HAdV-infected and non-HAdV-infected lung epithelial cells., Methods: We assessed the cellular and viral transcriptome of A549 cells infected and non-infected with HAdV C5 and treated or non-treated with BCV by RNAseq after 72 h., Results: BCV treatment of HAdV infected cells resulted in a profound decrease of viral transcription associated with a relative overexpression of the early genes E1A and E4 and of the late gene L1. BCV had also a profound impact on A549 cells' transcriptome. Ontologic analysis revealed an effect of BCV on several pathways known to interact with adenovirus replication as mTor signalling and Wnt pathways. A549 cells treated with BCV demonstrated a significant inhibition of the biological function of "viral replication" including 25 dysregulated genes involved in inflammation pathways., Conclusion: We demonstrated that BCV alters viral gene expression and promotes the expression of antiviral cellular pathways in A549 cells. These results provide new insights how to interfere with cellular pathways to control HAdV infections., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Human adenoviruses (HAdV) are ubiquitous within the human population and comprise a significant burden of respiratory illnesses worldwide. Pediatric and immunocompromised individuals are at particular risk for developing severe disease; however, no approved antiviral therapies specific to HAdV exist. Ivermectin is an FDA-approved broad-spectrum antiparasitic drug that also exhibits antiviral properties against a diverse range of viruses. Its proposed function is inhibiting the classical protein nuclear import pathway mediated by importin-α (Imp-α) and -β1 (Imp-β1). Many viruses, including HAdV, rely on this host pathway for transport of viral proteins across the nuclear envelope. In this study, we show that ivermectin inhibits HAdV-C5 early gene transcription, early and late protein expression, genome replication, and production of infectious viral progeny. Similarly, ivermectin inhibits genome replication of HAdV-B3, a clinically important pathogen responsible for numerous recent outbreaks. Mechanistically, we show that ivermectin disrupts binding of the viral E1A protein to Imp-α without affecting the interaction between Imp-α and Imp-β1. Our results further extend ivermectin's broad antiviral activity and provide a mechanistic underpinning for its mode of action as an inhibitor of cellular Imp-α/β1-mediated nuclear import. IMPORTANCE Human adenoviruses (HAdVs) represent a ubiquitous and clinically important pathogen without an effective antiviral treatment. HAdV infections typically cause mild symptoms; however, individuals such as children, those with underlying conditions, and those with compromised immune systems can develop severe disseminated disease. Our results demonstrate that ivermectin, an FDA-approved antiparasitic agent, is effective at inhibiting replication of several HAdV types in vitro This is in agreement with the growing body of literature suggesting ivermectin has broad antiviral activity. This study expands our mechanistic knowledge of ivermectin by showing that ivermectin targets the ability of importin-α (Imp-α) to recognize nuclear localization sequences, without effecting the Imp-α/β1 interaction. These data also exemplify the applicability of targeting host factors upon which viruses rely as a viable antiviral strategy., (Copyright © 2020 American Society for Microbiology.)

Human adenoviruses (HAdVs) are fatal to immuno-suppressed individuals, but no effective anti-HAdV therapy is available. Here, we present a novel image-based high-throughput screening (HTS) platform, which scores the full viral replication cycle from virus entry to dissemination of progeny and second-round infections. We analysed 1,280 small molecular weight compounds of the Prestwick Chemical Library (PCL) for interference with HAdV-C2 infection in a quadruplicate, blinded format, and performed robust image analyses and hit filtering. We present the entire set of the screening data including all images, image analyses and data processing pipelines. The data are made available at the Image Data Resource (IDR, idr0081). Our screen identified Nelfinavir mesylate as an inhibitor of HAdV-C2 multi-round plaque formation, but not single round infection. Nelfinavir has been FDA-approved for anti-retroviral therapy in humans. Our results underscore the power of image-based full cycle infection assays in identifying viral inhibitors with clinical potential.

Human adenovirus (HAdV) infection has an important clinical impact in the immunosuppressed population and is associated with high morbidity and mortality rates. The lack of a specific, safe and effective antiviral treatment against HAdV makes necessary the search for new therapeutic options. The aim of this study was to evaluate the in vitro activity of ganciclovir (GCV) against HAdV in co-infection by human cytomegalovirus (HCMV) and HAdV in cellular cultures. Quantitative real-time polymerase chain reaction (qPCR) was used to measure HAdV and HCMV DNA replication efficiency in monocultures and in co-infection situations in the presence of both cidofovir (CDV) and GCV. The effects of GCV and CDV were also evaluated in a burst assay (used to measure the production of virus particles) for both viruses, alone and in combination. GCV decreased by 1-log the HAdV DNA replication efficiency in co-infection with HCMV compared with its activity in HAdV monoculture. The burst assay showed that the reductions in virus yield in the presence of GCV were higher for HCMV and co-infection than for HAdV in monoculture (145.2±35.5- vs. 116.4±27.3- vs. 23.0±10.0-fold, respectively, P<0.05). The improved anti-HAdV activity of GCV during co-infection may be because of the more efficient phosphorylation of GCV by the HCMV protein kinase, UL97. Patients treated with GCV as pre-emptive therapy for HCMV infection may be considered as low-risk for developing HAdV infections; however, further evaluations are required to confirm these results., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Human adenoviruses (HAdVs) often cause mild respiratory infections. These infections, however, can potentially become fatal in immunosuppressive patients. Unfortunately, there has been no specific anti-HAdV drug approved for treatment of HAdV infections. In this study, a time-course transcriptome of HAdV-infected human lung epithelial cells (A549 cells) was performed and compared with perturbation datasets of 890 drug-treated A549 cells from the library of integrated network-based cellular signatures (LINCS) database to predict previously unknown therapeutic drug-HAdV relationships using a characteristic direction (CD) algorithm. We performed experiments to validate a prediction for the anti-diabetic drug rosiglitazone as a candidate drug for treatment of anti-HAdV both in vivo and in vitro. The Type I interferon (IFNs) signaling pathway was negatively regulated during the course of HAdV infection and rosiglitazone increased STAT1 phosphorylation for antiviral IFN response induction. Taken together, this study confirmed the prospect for re-exploitation of this FDA-approved drug as a potential therapeutic for HAdV infections., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The new epidemiological scenario has so far focused on the environmental circulation of human viral pathogens. Owing to the side effects of chemical disinfectants, there is an increasing need for knowledge on the use of virucidal compounds, especially those of a natural origin. Climacostol is a molecule produced by a freshwater ciliate and it exhibits activity against bacterial and fungal pathogens. We thus also speculated that there might be an effect on viral viability, which has never been tested. To evaluate such activity, we chose human adenovirus (HAdV), which is representative of waterborne viruses. We conducted experiments using HAdV serotype 5, whose titer was determined by infecting HeLa cell cultures. HAdV5 was shown to be sensitive to climacostol at a concentration of 0.0002 mg/mL, with an approximate 3 Log 10 reduction when the initial titer of HAdV5 was approximately 10 4 and 10 3 TCID 50 /mL. These preliminary results could be an important starting point for further research aimed at improving the characterization of climacostol activity under different experimental conditions and against various viruses, including enveloped ones (i.e., the coronavirus). The production of climacostol by a protist living in fresh water also suggests a possible application in the activated sludge of wastewater treatment plants.

Objective: To compare outcomes of early and delayed treatment with cidofovir for human adenovirus (HAdV) pneumonia., Methods: A retrospective cohort study in Korean military hospitals was conducted between January 2012 and December 2018. Patients with potentially severe HAdV pneumonia with risk factors for respiratory failure were included and divided into early (within 7 days from symptom onset) and delayed (after 7 days from symptom onset) treatment groups. The primary outcome was respiratory failure development within 21 days after symptom onset., Results: A total of 89 patients with potentially severe HAdV pneumonia were enrolled in the cohort; they included 62 early and 27 delayed treatment patients. All patients were males in their early 20s. Significantly fewer patients in the early treatment group progressed to respiratory failure (8/62, 12.9%), compared to the delayed group (18/27, 66.7%, p < 0.001). Early treatment was associated with a lower 21-day probability of respiratory failure by the Kaplan-Meier method (p < 0.001). On multivariate analysis, monocyte count, hypoxaemia, confusion, whole lung involvement, and early cidofovir treatment within 7 days from symptom onset were included, and monocyte count (HR 0.995, 95%CI 0.991-1.000, p 0.042), confusion (HR 4.964, 95%CI 1.189-20.721, p = 0.028), and early cidofovir treatment (HR 0.319, 95%CI 0.115-0.883, p = 0.028) were significantly associated with respiratory failure., Conclusions: Early administration of cidofovir was associated with a lower hazard for respiratory failure development. It is suggested that cidofovir be administered within 7 days from symptom onset to prevent respiratory failure in patients with potentially severe HAdV pneumonia., (Copyright © 2019 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

The effective treatment of adenovirus (HAdV) infections in immunocompromised patients still poses great challenges. Herein, we reported our continued efforts to optimize a series of salicylamide derivatives as potent inhibitors of HAdV infection. Of these, nine compounds ( 11 , 13 , 14 , 17 , 20 , 58 , 60 , 62 , and 70 ) showed significantly improved anti-HAdV activities with nanomolar to submicromolar IC 50 values and high selectivity indexes (SI > 100), indicating better safety windows, compared to those of the lead compound niclosamide. Our mechanistic assays suggest that compounds 13 , 62 , and 70 exert their activities in the HAdV entry pathway, while compounds 14 and 60 likely target the HAdV DNA replication, and 11, 17, 20 , and 58 inhibit later steps after DNA replication. Given the broad anti-viral activity profile of niclosamide, these derivatives may also offer therapeutic potential for other viral infections.

Coxsackievirus B3 (CVB3) is the most common cause of acute and chronic viral myocarditis, primarily in children, while human adenovirus infections represent a significant cause of morbidity and mortality worldwide, in people of all ages. A series of novel 2-benzoxyl-phenylpyridine derivatives were evaluated for their potential antiviral activities against CVB3 and adenovirus type 7 (ADV7). Preliminary assays indicated that some of these compounds exhibited excellent antiviral effects on both CVB3 and ADV7 viruses; they could effectively inhibit virus-induced cytopathic effects, reduce viral progeny yields, and had similar or superior antiviral activities compared with the control drug, ribavirin. Further, these compounds targeted the early stages of CVB3 replication in cells, including viral RNA replication and protein synthesis, rather than inactivating the virus directly, inhibiting virus adsorption/entry, or affecting viral release from cells. Our data demonstrate that the tested 2-benzoxyl-phenylpyridine derivatives are effective inhibitors of CVB3 and ADV7, raising the possibility that these compounds might be feasible candidates for anti-viral agents.

In recent years, human adenovirus (HAdV) infections have shown a high clinical impact in both immunosuppressed and immunocompetent patients. The research into specific antiviral drugs for the treatment of HAdV infections in immunocompromised patients constitutes a principal objective for medicinal chemistry due to the lack of any specific secure drug to treat these infections. In this study, we report a small-molecule library (67 compounds) designed from an optimization process of piperazine-derived urea privileged structures and their biological evaluation: antiviral activity and cytotoxicity. The active compounds selected were further evaluated to gain mechanistic understanding for their inhibition. Twelve derivatives were identified that inhibited HAdV infections at nanomolar and low micromolar concentrations (IC 50 from 0.6 to 5.1 μM) with low cytotoxicity. In addition, our mechanistic assays suggested differences in the way the derivatives exert their anti-HAdV activity targeting transcription, DNA replication and later steps in the HAdV replication cycle. Furthermore, eight of the 12 studied derivatives blocked human cytomegalovirus (HCMV) DNA replication at low micromolar concentrations. The data provided herein indicates that the 12 thiourea/urea piperazine derivatives studied may represent potential lead compounds for clinical evaluation and development of new anti-HAdV drugs., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Human adenovirus type 19 (HAdV-19) is a major cause of the epidemic keratoconjunctivitis. Outbreaks of keratoconjunctivitis are problematic to human health, especially for infants, the elderly, and immunocompromised individuals. However, the development of anti-HAdV drugs has been hampered by inconvenient screening systems; therefore, development of a simple screening method is highly desirable. In this study, we identified that HAdV-19 can infect a human lymphoid cell line transformed with human T-cell leukemia virus (MT-2 cells). MT-2 cells supported HAdV-19 replication and showed apparent cytopathic effects within five days post-infection. Using a thiazolyl blue tetrazolium bromide (MTT)-based colorimetric assay on MT-2 cells, we were able to detect the anti-HAdV-19 activities of previously reported nucleoside/tide compounds, including (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (cidofovir), 2',3'-dideoxycytidine (zalcitabine) and 3'-deoxy-3'-fluorothymidine (trifluridine). Compared with previous methods, this system represents a more simple and rapid method to screen anti-HAdV-19 agents.

Human adenovirus (HAdV) can cause severe disease and death in both immunocompromised and immunocompetent patients. The current standards of treatment are often ineffective, and no approved antiviral therapy against HAdV exists. We report here the design and validation of a fluorescence-based high-content screening platform for the identification of novel anti-HAdV compounds. The screen was conducted using a wildtype-like virus containing the red fluorescent protein (RFP) gene under the regulation of the HAdV major late promoter. Thus, RFP expression allows monitoring of viral late gene expression (a surrogate marker for virus replication), and compounds affecting virus growth can be easily discovered by quantifying RFP intensity. We used our platform to screen ~1200 FDA-approved small molecules, and identified several cardiotonic steroids, corticosteroids and chemotherapeutic agents as anti-HAdV compounds. Our screening platform provides the stringency necessary to detect compounds with varying degrees of antiviral activity, and facilitates drug discovery/repurposing to combat HAdV infections., (Copyright © 2019. Published by Elsevier Inc.)

Ribavirin is a molecule with antiviral activity against different viruses. In clinical practice, it has made its niche almost exclusively for the treatment of the hepatitisC virus. However, there are other diseases in which it could be of benefit and it has the advantage of being suitable for oral, intravenous and inhaled administration. We conducted a review of the indications of the main drug agencies (Spanish, European and American) and other possible indications, mainly haemorrhagic fevers and coronavirus., (Copyright © 2018 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.)

Five tungsten carbide nanoparticle preparations (denoted WC1-WC5) were investigated for broad spectrum virucidal activity against four recommended model viruses. These are modified vaccinia virus Ankara (MVA), human adenovirus type 5 (HAdV-5), poliovirus type 1 (PV-1) and murine norovirus (MNV). All virucidal tests were performed two to five times using the quantitative suspension test, which is a highly standardized test method to evaluate the virucidal efficacy of disinfectants in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Quantitative detection of viruses was conducted by endpoint titration and quantitative real-time PCR. Results showed that three of the five tested compounds (WC1-WC3) were able to reduce the infectivity of all model viruses by at least four log 10 of tissue culture infective dose 50% per ml after 15 min, whereas the other two compounds exhibited only limited efficacy (WC4) or showed cytotoxicity (WC5). Virucidal activity of nanoparticles increased with incubation time and a dose-effect curve showed dependence of virucidal activity with particle concentration. Whereas WC1-WC4 showed little cytotoxicity, WC5 which was doped with copper exhibited a significant cytotoxic effect. These findings propose tungsten carbide nanoparticles to be very promising in terms of new disinfection techniques. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study investigates the virucidal activity of tungsten carbide nanoparticles using the quantitative suspension test in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Due to highly standardized assay conditions, results of this test are considered very reliable for evaluation of the virucidal activity of disinfectants. Broad-spectrum activity and high efficacy of three different tungsten carbide nanoparticles preparations is concluded., (© 2019 The Society for Applied Microbiology.)

The surface of proteins is heterogeneous with sophisticated but precise hydrophobic and hydrophilic patches, which is essential for their diverse biological functions. To emulate such distinct surface patterns on macromolecules, we used rigid spherical synthetic dendrimers (polyphenylene dendrimers) to provide controlled amphiphilic surface patches with molecular precision. We identified an optimal spatial arrangement of these patches on certain dendrimers that enabled their interaction with human adenovirus 5 (Ad5). Patchy dendrimers bound to the surface of Ad5 formed a synthetic polymer corona that greatly altered various host interactions of Ad5 as well as in vivo distribution. The dendrimer corona (1) improved the ability of Ad5-derived gene transfer vectors to transduce cells deficient for the primary Ad5 cell membrane receptor and (2) modulated the binding of Ad5 to blood coagulation factor X, one of the most critical virus-host interactions in the bloodstream. It significantly enhanced the transduction efficiency of Ad5 while also protecting it from neutralization by natural antibodies and the complement system in human whole blood. Ad5 with a synthetic dendrimer corona revealed profoundly altered in vivo distribution, improved transduction of heart, and dampened vector sequestration by liver and spleen. We propose the design of bioactive polymers that bind protein surfaces solely based on their amphiphilic surface patches and protect against a naturally occurring protein corona, which is highly attractive to improve Ad5-based in vivo gene therapy applications.

Background and objectives : The use of antagonistic probiotic microorganisms and their byproducts represents a promising approach for the treatment of viral diseases. In the current work, the effect of exopolysaccharides (EPSs) produced by lactic acid bacteria from different genera on the structural and functional characteristics of cells and the development of adenoviral infection in vitro was studied. Materials and Methods: Cytotoxicity of six EPSs of lactic acid bacteria of the genera Lactobacillus, Leuconostoc and Pediococcus was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The influence of the EPSs on the infectivity of human adenovirus type 5 (HAdV-5) and on the cell cycle under a condition of adenovirus infection was studied using plaque reduction assay and flow cytometric analysis, respectively. Results : It was shown that exopolysaccharides were non-toxic to Madin-Darby bovine kidney cells (MDBK) as they reduced their viability by 3-17%. A change in the distribution of the cell cycle phases in the non-infected cell population treated with EPSs was observed. The analysis demonstrated an increase in the number of cells in the S phase by 47% when using EPSs 15a and a decrease in the number of cells in the G1 phase by 20-27% when treated with the EPSs 15a, 33a, and 19s. The use of EPSs did not led to the normalization of the life cycle of HAdV-5 infected cells to the level of non-infected cells. The EPSs showed low virucidal activity and reduced the HAdV-5 infectivity to 85%. Among the studied exopolysaccharides, anti-adenovirus activity was found for EPS 26a that is produced by Lactobacillus spp. strain. The treatment of cells with the EPS following virus adsorption completely (100%) suppressed the formation and release of HAdV-5 infectious. Conclusions: EPS 26a possessed distinct anti-HAdV-5 activity and the obtained data demonstrate the potential of using exopolysaccharides as anti-adenoviral agents., Competing Interests: The authors declare no conflict of interest.

Background: The use of disinfectant wipes in hospitals is increasing over the last years. These wipes should be able to inactivate microorganisms including viruses on environmental surfaces and to prevent their transfer to clean areas.The European norm (EN) 16615:2015 describes a wiping process over four fields starting on the contaminated field 1 followed by fields 2-4 and back to the starting point (4-field test). This test method exclusively describes killing and transfer of vegetative bacteria and fungi by disinfectant wipes without measuring virucidal activities. Therefore, it was the aim of this study to use the existing test methodology additionally to evaluate virus inactivation by wipes., Methods: The 4-field test was performed with four commercially available disinfectant wipes including the examination of the active solutions of these wipes with a reference wipe. Murine norovirus (MNV) as surrogate of human noroviruses, adenovirus (AdV) type 5 and polyomavirus SV40 (SV40) were chosen as test viruses., Results: The per acetic acid (PAA)-based wipe (wipe A) was able to inactivate all three test viruses resulting in a four log 10 reduction on test field 1, whereas the quaternary ammonium compound (QAC)-based products (wipes B and C) failed to reach such reduction. Both QAC-based wipes were able to inactivate SV40 and only the active solution of wipe B was effective against MNV. Another wipe with 2-propanol as active ingredient (wipe D) was not able to show a sufficient efficacy against all three test viruses. There was a good agreement between the results of the wipes and the corresponding fluids showing no influence of the material of wipes.Tests with the 2-propanol-based wipe D showed a transfer of all test viruses to the non-contaminated test fields 2-4. SV40 was additionally transferred by the QAC-based wipe C with 0.78% active ingredients to these additional fields. In all other cases no virus transfer to test fields 2-4 was observed. Finally, no virus could be detected in the PAA-based wipe A after usage in the 4-field test in contrast to the other wipes examined., Conclusions: The successful performance of a 4-field test with viruses demonstrated that the existing wiping method with bacteria and fungi can be used in addition for measuring virucidal efficacy. The virus-inactivating properties of surface disinfectants could be evaluated therefore with a test simulating practical conditions with mechanical action resulting in more reliable data than the existing quantitative suspension tests and/or a carrier test without any mechanical action., Competing Interests: Competing interestsThe authors declare that they have no competing interests.

The symptoms of human adenovirus infections are generally mild and self-limiting. However, these infections have been gaining importance in recent years because of a growing number of immunocompromised patients. Solid organ and hematopoietic stem cell transplant patients are subjected to severe immunosuppressive regimes and cannot efficaciously eliminate virus infections. In these patients, adenovirus infections can develop into deadly multi-organ disseminated disease. Presently, in the absence of approved therapies, physicians rely on drugs developed for other purposes to treat adenovirus infections. As there is a need for anti-adenoviral therapies, researchers have been developing new agents and repurposing existing ones to treat adenovirus infections. There are several small molecule drugs that are being tested for their efficacy against human adenoviruses; some of these have reached clinical trials, while others are still in the preclinical phase. Besides these compounds, research on immunotherapy against adenoviral infection has made significant progress, promising another modality for treatment. The availability of an animal model confirmed the activity of some drugs already in clinical use while proving that others are inactive. This led to the identification of several lead compounds that await further development. In the present article, we review the current status of anti-adenoviral therapies and their advancement by in vivo studies in the Syrian hamster model., (© FEMS 2019.)

Millions of people use contaminated water sources for direct consumption. Chlorine is the most widely disinfection product but can produce toxic by-products. In this context, natural and synthetic compounds can be an alternative to water disinfection. Therefore, the aim of this study was to assess the inactivation of human adenovirus by N-chlorotaurine (NCT), bromamine-T (BAT) and Grape seed extract (GSE) in water. Distilled water artificially contaminated with recombinant human adenovirus type 5 (rAdV-GFP) was treated with different concentrations of each compound for up to 120 min, and viral infectivity was assessed by fluorescence microscopy. The decrease in activity of the compounds in the presence of organic matter was evaluated in water supplemented with peptone. As results, NCT and GSE inactivated approximately 2.5 log 10 of adenovirus after 120 min. With BAT, more than 4.0 log 10 decrease was observed within 10 min. The oxidative activity of 1% BAT decreased by 50% in 0.5% peptone within a few minutes, while the reduction was only 30% for 1% NCT in 5% peptone after 60 min. Organic matter had no effect on the activity of GSE. Moreover, the minimal concentration of BAT and GSE to kill viruses was lower than that known to kill human cells. It was concluded that the three compounds have potential to be used for water disinfection for drinking or reuse purposes.

Human adenovirus (HAdV) causes minor illnesses in most patients but can lead to severe disease and death in pediatric, geriatric, and immunocompromised individuals. No approved antiviral therapy currently exists for the treatment of these severe HAdV-induced diseases. In this study, we show that the pan-histone deacetylase (HDAC) inhibitor SAHA reduces HAdV-5 gene expression and DNA replication in tissue culture, ultimately decreasing virus yield from infected cells. Importantly, SAHA also reduced gene expression from more virulent and clinically relevant serotypes, including HAdV-4 and HAdV-7. In addition to SAHA, several other HDAC inhibitors (e.g., trichostatin A, apicidin, and panobinostat) also affected HAdV gene expression. We determined that loss of class I HDAC activity, mainly HDAC2, impairs efficient expression of viral genes, and that E1A physically interacts with HDAC2. Our results suggest that HDAC activity is necessary for HAdV replication, which may represent a novel pharmacological target in HAdV-induced disease. IMPORTANCE Although human adenovirus (HAdV) can cause severe diseases that can be fatal in some populations, there are no effective treatments to combat HAdV infection. In this study, we determined that the pan-histone deacetylase (HDAC) inhibitor SAHA has inhibitory activity against several clinically relevant serotypes of HAdV. This U.S. Food and Drug Administration-approved compound affects various stages of the virus lifecycle and reduces virus yield even at low concentrations. We further report that class I HDAC activity, particularly HDAC2, is required for efficient expression of viral genes during lytic infection. Investigation of the mechanism underlying SAHA-mediated suppression of HAdV gene expression and replication will enhance current knowledge of virus-cell interaction and may aid in the development of more effective antivirals with lower toxicity for the treatment of HAdV infections., (Copyright © 2019 American Society for Microbiology.)

Epidemic keratoconjunctivitis (EKC) is a severe ocular disease and can lead to visual impairment. Human adenovirus type-37 (HAdV-D37) is one of the major causative agents of EKC and uses sialic acid (SA)-containing glycans as cellular receptors. Currently, there are no approved antivirals available for the treatment of EKC. Recently, we have reported that sulfated glycosaminoglycans (GAGs) bind to HAdV-D37 via the fiber knob (FK) domain of the viral fiber protein and function as decoy receptors. Based on this finding, we speculated that GAG-mimetics may act as artificial decoy receptors and inhibit HAdV-D37 infection. Repurposing of approved drugs to identify new antivirals has drawn great attention in recent years. Here, we report the antiviral effect of suramin, a WHO-approved drug and a widely known GAG-mimetic, against HAdV-D37. Commercially available suramin analogs also show antiviral effects against HAdV-D37. We demonstrate that suramin exerts its antiviral activity by inhibiting the attachment of HAdV-D37 to cells. We also reveal that the antiviral effect of suramin is HAdV species-specific. Collectively, in this proof of concept study, we demonstrate for the first time that virus binding to a decoy receptor constitutes a novel and an unexplored target for antiviral drug development.

Human adenovirus (AdV) can cause fatal disease in immune-suppressed individuals, but treatment options are limited, in part because the antiviral cytidine analog cidofovir (CDV) is nephrotoxic. The investigational agent brincidofovir (BCV) is orally bioavailable, nonnephrotoxic, and generates the same active metabolite, cidofovir diphosphate (CDVpp). However, its mechanism of action against AdV is poorly understood. Therefore, we have examined the effect of CDVpp on DNA synthesis by a purified adenovirus 5 (AdV5) DNA polymerase (Pol). CDVpp was incorporated into nascent DNA strands and promoted a nonobligate form of chain termination (i.e., AdV5 Pol can extend, albeit inefficiently, a DNA chain even after the incorporation of a first CDVpp molecule). Moreover, unlike a conventional mismatched base pair, misincorporated CDVpp was not readily excised by the AdV5 Pol. At elevated concentrations, CDVpp inhibited AdV5 Pol in a manner consistent with both chain termination and direct inhibition of Pol activity. Finally, a recombinant AdV5 was constructed, containing Pol mutations (V303I and T87I) that were selected following an extended passage of wild-type AdV5 in the presence of BCV. This virus had a 2.1-fold elevated 50% effective concentration (EC 50 ) for BCV and a 1.9-fold increased EC 50 for CDV; thus, these results confirmed that viral resistance to BCV and CDV can be attributed to mutations in the viral Pol. These findings show that the anti-AdV5 activity of CDV and BCV is mediated through the viral DNA Pol and that their antiviral activity may occur via both (nonobligate) chain termination and (at high concentration) direct inhibition of AdV5 Pol activity., (Copyright © 2018 American Society for Microbiology.)

Background and objectives: A considerable increase in the levels of adenoviral diseases among both adults and children necessitate the development of effective methods for its prevention and treatment. The synthesis of the new fluorinated 1,2,3-triazoles, and the study of the mechanisms of their action, are promising for the development of efficient antiviral drugs of our time. Materials and Methods: Antiviral activity and cell cytotoxic effect of 2-(3-chlorotetrahydrofuran-2-yl)-4-tosyl-5-(perfluoropropyl)-1,2,3-triazole (G29) were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The influence of the compound on the infectivity of human adenovirus type 5 (HAdV-5) was carried out via the cytomorphology method. The influence of the compound on the cell cycle under a condition of adenovirus infection was studied using flow cytometric analysis of propidium iodide-stained cells. Results: It was found that G29 suppressed HAdV-5 reproduction by 50% in concentrations of 37 μg/mL. Furthermore, the compound reduced the titer of virus obtained de novo, and inhibited HAdV-5 inclusion bodies formation by 84⁻90%. The use of fluorinated compounds under the conditions of adenovirus infection decreased the number of apoptotic cells by 11% and the number of cells in S phase by 21⁻42% compared to the profile of infected cells. Conclusions: The fluorinated compound G29 showed moderate activity against HAdV-5 based on several mechanisms. It led to the normalization of the life cycle of cells infected with adenovirus to the level of non-infected cells and caused the obstruction of HAdV-5 reproduction, inducing the formation of non-infectious virus progeny.

The repurposing of drugs approved by the regulatory agencies for other indications is emerging as a valuable alternative for the development of new antimicrobial therapies, involving lower risks and costs than the de novo development of novel antimicrobial drugs. Adenovirus infections have showed a steady increment in recent years, with a high clinical impact in both immunosuppressed and immunocompetent patients. In this context, the lack of a specific drug to treat these infections supports the search for new therapeutic alternatives. In this study, we examined the anti-HAdV properties of mifepristone, a commercially available synthetic steroid drug. Mifepristone showed significant in vitro anti-HAdV activity at low micromolar concentrations with little cytotoxicity. Our mechanistic assays suggest that this drug could affect the microtubule transport, interfering with the entry of the virus into the nucleus and therefore inhibiting HAdV infection., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Hand antiseptics are of great importance in the prevention of nosocomial infections. Due to the frequent occurrence of adenoviral epidemic keratoconjunctivitis outbreaks in the study hospital, it was necessary to investigate the efficiency of alcohol-based solutions on adenoviruses., Aim: To investigate the efficacy of alcohol-based solutions commonly found in hand antiseptics against adenovirus serotypes 8, 19 and 37., Methods: The efficacy of ethanol, isopropanol, chlorhexidine-digluconate, n-butanol and different combinations of these antiseptics on adenovirus serotypes that typically cause epidemic keratoconjunctivitis was investigated. The effect of antiseptic substances was investigated using a quantitative suspension test technique according to EN-14476. Antiseptics were prepared as follows: 70% ethanol, 70% isopropanol, 70% ethanol+0.5% chlorhexidine-digluconate, 70% isopropanol+0.5% chlorhexidine-digluconate, 60% ethanol+10% isopropanol, 60% ethanol+10% isopropanol+0.5% chlorhexidine-digluconate and 60% ethanol+10% isopropanol+1% n-butanol. The effect of antiseptics was evaluated at 30, 60 and 120 s., Findings: The highest reduction in virus titre was detected with 60% ethanol+10% isopropanol+1% n-butanol. This caused a reduction of 2.5log 10 , 3 log 10 and 2.5log 10 in adenovirus serotypes 8, 19 and 37, respectively. The lowest reduction in virus titre was detected with 70% ethanol+0.5% chlorhexidine-digluconate and 70% isopropanol+0.5% chlorhexidine-digluconate. These combinations caused a reduction of 1.62log 10 in adenovirus serotypes 19 and 37. All antiseptics showed efficacy levels below 4log 10 which is regarded as the efficiency limit by EN-14476., Conclusion: The alcohol-based solutions tested in this study were not found to be sufficiently effective against adenovirus serotypes. Further studies to investigate the efficiency of different alcohol-based solutions are required., (Copyright © 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.)

On September 22, 2008, a physician on Prince of Wales Island, Alaska, notified the Alaska Department of Health and Social Services (ADHSS) of an unusually high number of adult patients with recently diagnosed pneumonia (n = 10), including three persons who required hospitalization and one who died. ADHSS and CDC conducted an investigation to determine the cause and distribution of the outbreak, identify risk factors for hospitalization, and implement control measures. This report summarizes the results of that investigation, which found that the outbreak was caused by adenovirus 14 (Ad14), an emerging adenovirus serotype in the United States that is associated with a higher rate of severe illness compared with other adenoviruses. Among the 46 cases identified in the outbreak from September 1 through October 27, 2008, the most frequently observed characteristics included the following: male (70%), Alaska Native (61%), underlying pulmonary disease (44%), aged > or = 65 years (26%), and current smoker (48%). Patients aged > or = 65 years had a fivefold increased risk for hospitalization. The most commonly reported symptoms were cough (100%), shortness of breath (87%), and fever (74%). Of the 11 hospitalized patients, three required intensive care, and one required mechanical ventilation. One death was reported. Ad14 isolates obtained during the outbreak were identical genetically to those in recent community-acquired outbreaks in the United States which suggests the emergence of a new, and possibly more virulent Ad14 variant. Clinicians should consider Ad14 infection in the differential diagnosis for patients with community-acquired pneumonia, particularly when unexplained clusters of severe respiratory infections are detected., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Purpose: To evaluate the efficacy/safety of an ophthalmic suspension of povidone-iodine (PVP-I) 0.6% and dexamethasone 0.1% in patients with acute adenoviral conjunctivitis., Design: Multicenter, randomized, vehicle-controlled, double-masked trial., Methods: Adults with a positive Rapid Pathogen Screening Adeno-Detector Plus test were randomized 1:1:1 to PVP-I 0.6%/dexamethasone 0.1%, PVP-I 0.6%, or vehicle, bilaterally 4 times daily for 5 days (days 1-5). Patients were evaluated on days 3, 6, and 12 (+1-day window). Efficacy measures included clinical resolution and adenoviral eradication., Results: Overall, 144 patients were included in the efficacy analysis (PVP-I/dexamethasone, n = 48; PVP-I, n = 50; vehicle, n = 46). The proportion of patients with clinical resolution (primary study eye with last observation carried forward [LOCF]) at the day 6 visit was higher with PVP-I/dexamethasone (31.3%) than with vehicle (10.9%; P = .0158) and PVP-I (18.0%; P = nonsignificant). The proportion with adenoviral eradication (primary study eye with LOCF) was higher with PVP-I/dexamethasone than with vehicle at the day 3 (35.4% vs 8.7%; P = .0019) and day 6 (79.2% vs 56.5%; P = .0186) visits and vs PVP-I (day 3 visit, 32.0%; day 6 visit, 62.0%; each P = nonsignificant). Treatment-emergent adverse events (AEs) occurred in 69.0% (vehicle), 62.7% (PVP-I), and 53.4% (PVP-I/dexamethasone) of patients in the safety dataset. Discontinuation owing to AEs occurred in 37 patients (vehicle, n = 16; PVP-I, n = 12; PVP-I/dexamethasone, n = 9)., Conclusion: PVP-I/dexamethasone appeared safe and well tolerated, and significantly improved clinical resolution and adenoviral eradication in patients with acute adenoviral conjunctivitis., (Copyright © 2018 Shire, Lexington, MA, USA. Published by Elsevier Inc. All rights reserved.)

Human adenoviruses (AdV) cause generally mild infections of the respiratory and GI tracts as well as some other tissues. However, AdV can cause serious infection in severely immunosuppressed individuals, especially pediatric patients undergoing allogeneic hematopoietic stem cell transplantation, where mortality rates are up to 80% with disseminated disease. Despite the seriousness of AdV disease, there are no drugs approved specifically to treat AdV infections. We report here that USC-087, an N-alkyl tyrosinamide phosphonate ester prodrug of HPMPA, the adenine analog of cidofovir, is highly effective against multiple AdV types in cell culture. USC-087 is also effective against AdV-C6 in our immunosuppressed permissive Syrian hamster model. In this model, hamsters are immunosuppressed by treatment with high dose cyclophosphamide. Injection of AdV-C6 (or AdV-C5) intravenously leads to a disseminated infection that resembles the disease seen in humans, including death. We have tested the efficacy of orally-administered USC-087 against the median lethal dose of intravenously administered AdV-C6. USC-087 completely prevented or significantly decreased mortality when administered up to 4 days post challenge. USC-087 also prevented or significantly decreased liver damage caused by AdV-C6 infection, and suppressed virus replication even when administered 4 days post challenge. These results imply that USC-087 is a promising candidate for drug development against HAdV infections., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Human adenoviruses (HAdVs) usually cause mild respiratory infections, but they can also lead to fatal outcomes for immunosuppressive patients. Unfortunately, there has been no specific anti-HAdV drug approved for medical use. A better understanding of the nature of virus-host interactions during infection is beneficial to the discovery of potential antiviral targets and new antiviral drugs. In this study, a time-course transcriptome analysis of HAdV-infected human lung epithelial cells (A549 cells) was performed to investigate virus-host interactions, and several key host molecules involved in the HAdV infection process were identified. The RARβ (retinoic acid receptor β) molecule, one of the upstream regulatory factors of differentially expressed genes (DEGs), played important roles in HAdV replication. The results of reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting showed that RARβ mRNA and protein were downregulated by HAdV infection in the A549 cells. The knockdown of RARβ by RARβ siRNA increased the HAdV production and the overexpression of RARβ decreased the HAdV production. Furthermore, FDA-approved Tazarotene, which is an RAR selective agonist with relatively more selectivity for RARβ, was found to inhibit HAdV replication in vitro. Taken together, our study presents a key host molecule in adenovirus infection, which could be developed as a potential host target to an anti-adenovirus drug. In addition, this study provides evidence for the re-exploitation of an FDA-approved small molecule for therapeutic applications in adenovirus replication., (Copyright © 2018. Published by Elsevier B.V.)

Background: Human adenoviral (HAdV) infections are usually mild and self-limited, however, some infections from species A, B, C, D and E, can cause severe illnesses, which have raised public health concerns over the past few years. Current available antiviral therapies have limited efficacy and severe toxicity; therefore, finding new targets for specific anti-adenoviral drug design is urgently needed. Our previous work showed that the small molecule compound, HBX, inhibits HAdV type 5 (species C, HAdV-C5) replication and oncogenic transformation through inhibition of the cellular pro-viral factor ubiquitin-specific protease 7 (USP7). Here, we have tested the ability of HBX to inhibit other HAdV species, as well as different clinical isolates that are the cause of severe infections., Methods: We treated HAdV-infected A549 cells with different concentrations of HBX and analysed the antiviral efficacy of the drug by determining the half maximal inhibitory concentration (IC50) necessary to decrease both viral genome copies and virus progeny production at different time points after infection., Results: In addition to its effect on HAdV-C5, HBX was able to significantly inhibit virus genome replication and progeny release of all adenovirus types tested, with the exception of types 12 and 31, from species A. Of note, clinical isolates were more sensitive to HBX treatment than their prototype strains., Conclusions: These results point to HBX as a promising broad-spectrum anti-adenoviral drug, opening new opportunities to prevent severe adenoviral infections and to improve their treatment.