Search

Viral manipulation of posttranslational modifications (PTMs) is critical to enable control over host defenses. Evidence suggests that one such PTM, adenosine 5-diphosphate (ADP)-ribosylation, is important for viral replication, but the host and viral components involved are poorly understood. Here, we demonstrate that several human poly(ADP-ribose) polymerase (PARP) proteins, including the zinc-finger domain containing PARP7 (TiPARP) and PARP12, directly ADP-ribosylate the alphaviral nonstructural proteins (nsPs), nsP3 and nsP4. These same human PARP proteins inhibit alphavirus replication in a manner that can be antagonized by the ADP-ribosylhydrolase activity of the virally encoded macrodomain. Last, we find that knockdown of any of the three CCCH zinc-finger domain containing PARPs, PARP7, PARP12, or the enzymatically inactive PARP13 (ZAP/ZC3HAV1), attenuates the antiviral effects of interferon-γ on alphavirus replication. Combined with evolutionary analyses, these data suggest that zinc-finger PARPs share an ancestral antiviral function that can be antagonized by the activity of viral macrodomains, indicative of an ongoing evolutionary conflict between host ADP-ribosylation and viruses.

Mx proteins, first identified in mammals, encode potent antiviral activity against a wide range of viruses. Mx proteins arose within the Dynamin superfamily of proteins (DSP), which mediate critical cellular processes, such as endocytosis and mitochondrial, plastid, and peroxisomal dynamics. Despite their crucial role, the evolutionary origins of Mx proteins are poorly understood. Through comprehensive phylogenomic analyses with progressively expanded taxonomic sampling, we demonstrate that Mx proteins predate the interferon signaling system in vertebrates. Our analyses find an ancient monophyletic DSP lineage in eukaryotes that groups vertebrate and invertebrate Mx proteins with fungal MxF proteins, the largely uncharacterized plant and algal Dynamin 4A/4C proteins, and representatives from several other eukaryotic lineages, suggesting that Mx-like proteins date back close to the origin of Eukarya. Our phylogenetic analyses also find host-encoded and nucleocytoplasmic large DNA viruses-encoded DSPs interspersed in four distinct DSP lineages, indicating recurrent viral theft of host DSPs. Our analyses thus reveal an ancient history of viral and antiviral functions encoded by the Dynamin superfamily in eukaryotes.

BACKGROUND: Disparities persist in testing and treatment for hepatitis C virus (HCV), leaving socially marginalized populations, including people who inject drugs (PWID), less likely to benefit from curative treatment. Linkage services are often insufficient to overcome barriers to navigating the medical system and contextual factors. METHODS: The Youre Empowered for Treatment Initiation (YETI) Partner trial is a single-site randomized controlled trial evaluating the efficacy of a two-session behavioral intervention that engages injecting partners as peer navigators for HCV treatment. We aim to recruit 250 PWID and their primary injecting partners in San Francisco, California, randomizing them 1:1 to either a control or intervention group. The primary outcome is the initiation of HCV treatment, with secondary outcomes including treatment completion and sustained virologic response 12 weeks post-treatment. Data will be collected through questionnaires and electronic health records and analyzed using intention-to-treat and mixed-effects models. DISCUSSION: This trial will provide evidence of a new HCV treatment linkage intervention leveraging the support of primary injecting partners to initiate HCV treatment. If successful, the intervention could inform public health strategies and policies to address HCV in marginalized populations. TRIAL REGISTRATION: ClinicalTrials.gov NCT06179498. Registered on December 22, 2023.

Dengue, West Nile, Zika, Yellow fever, and Japanese encephalitis viruses persist as significant global health threats. The development of new therapeutic strategies based on inhibiting essential viral enzymes or viral-host protein interactions is problematic due to the fast mutation rate and rapid emergence of drug resistance. This study focuses on the NS2B-NS3 protease as a promising target for antiviral drug development. Promising allosteric binding sites were identified in two conformationally distinct inactive states and characterized for five flaviviruses and four Dengue virus subtypes. Their shapes, druggability, inter-viral similarity, sequence variation, and susceptibility to drug-resistant mutations have been studied. Two identified allosteric inactive state pockets appear to be feasible alternatives to a larger closed pocket near the active site, and they can be targeted with specific drug-like small-molecule inhibitors. Virus-specific sequence and structure implications and the feasibility of multi-viral inhibitors are discussed.

Chronic hepatitis B remains a substantial global health challenge, impacting approximately 254 million people worldwide. A cure for this condition is yet to be discovered. Early identification and effective treatments coupled with vigilant monitoring can help alleviate associated morbidity and mortality due to potential complications such as liver cirrhosis and hepatocellular carcinoma.

BackgroundMany respiratory viruses attack the airway epithelium and cause a wide spectrum of diseases for which we have limited therapies. To date, a few primary human stem cell-based models of the proximal airway have been reported for drug discovery but scaling them up to a higher throughput platform remains a significant challenge. As a result, most of the drug screening assays for respiratory viruses are performed on commercial cell line-based 2D cultures that provide limited translational ability.MethodsWe optimized a primary human stem cell-based mucociliary airway epithelium model of SARS-CoV-2 infection, in 96-well air-liquid-interface (ALI) format, which is amenable to moderate throughput drug screening. We tested the model against SARS-CoV-2 parental strain (Wuhan) and variants Beta, Delta, and Omicron. We applied this model to screen 2100 compounds from targeted drug libraries using a high throughput-high content image-based quantification method.ResultsThe model recapitulated the heterogeneity of infection among patients with SARS-CoV-2 parental strain and variants. While there were heterogeneous responses across variants for host factor targeting compounds, the two direct-acting antivirals we tested, Remdesivir and Paxlovid, showed consistent efficacy in reducing infection across all variants and donors. Using the model, we characterized a new antiviral drug effective against both the parental strain and the Omicron variant.ConclusionThis study demonstrates that the 96-well ALI model of primary human mucociliary epithelium can recapitulate the heterogeneity of infection among different donors and SARS-CoV-2 variants and can be used for moderate throughput screening. Compounds that target host factors showed variability among patients in response to SARS-CoV-2, while direct-acting antivirals were effective against SARS-CoV-2 despite the heterogeneity of patients tested.

BACKGROUND: Reducing hospital readmission offer potential benefits for patients, providers, payers, and policymakers to improve quality of healthcare, reduce cost, and improve patient experience. We investigated effectiveness of remdesivir in reducing 30-day coronavirus disease 2019 (COVID-19)-related readmission during the Omicron era, including older adults and those with underlying immunocompromising conditions. METHODS: This retrospective study utilized the US PINC AI Healthcare Database to identify adult patients discharged alive from an index COVID-19 hospitalization between December 2021 and February 2024. Odds of 30-day COVID-19-related readmission to the same hospital were compared between patients who received remdesivir vs those who did not, after balancing characteristics of the two groups using inverse probability of treatment weighting (IPTW). Analyses were stratified by maximum supplemental oxygen requirement during index hospitalization. RESULTS: Of 326 033 patients hospitalized for COVID-19 during study period, 210 586 patients met the eligibility criteria. Of these, 109 551 (52%) patients were treated with remdesivir. After IPTW, lower odds of 30-day COVID-19-related readmission were observed in patients who received remdesivir vs those who did not, in the overall population (3.3% vs 4.2%, respectively; odds ratio [95% confidence interval {CI}]: 0.78 [.75-.80]), elderly population (3.7% vs 4.7%, respectively; 0.78 [.75-.81]), and those with underlying immunocompromising conditions (5.3% vs 6.2%, respectively; 0.86 [.80-.92]). These results were consistent irrespective of supplemental oxygen requirements. CONCLUSIONS: Treating patients hospitalized for COVID-19 with remdesivir was associated with a significantly lower likelihood of 30-day COVID-19-related readmission across all patients discharged alive from the initial COVID-19 hospitalization, including older adults and those with underlying immunocompromising conditions.

BACKGROUND: Coronavirus disease 2019 (COVID-19) remains a major public health concern, with continued resurgences of cases and substantial risk of mortality for hospitalized patients. Remdesivir has become standard-of-care for hospitalized COVID-19 patients. Given the continued evolution of the disease, clinical management of COVID-19 relies on evidence from the current endemic period. METHODS: Using the PINC AI Healthcare Database, remdesivir effectiveness was evaluated among adults hospitalized with primary diagnosis of COVID-19 between December 2021 and February 2024. Three cohorts were analyzed: adults (≥18 years), elderly (≥65 years), and those with documented COVID-19 pneumonia. Analyses were stratified by oxygen requirements. Patients who received remdesivir were matched to those who did not receive remdesivir using propensity score matching. Cox proportional hazards models were used to examine in-hospital mortality. RESULTS: 169 965 adults hospitalized for COVID-19 were included, of whom 94 129 (55.4%) initiated remdesivir in the first 2 days of hospitalization. Remdesivir was associated with significantly lower mortality rate compared to no remdesivir among patients with no supplemental oxygen charges (adjusted HR [95% CI]: 14-day, 0.75 [.69-.82]; 28-day, 0.77 [.72-.83]) and those requiring supplemental oxygen: 14-day, 0.76 [.72-.81]; 28-day, 0.79 [.74-.83]; P < .0001 for all). Similar findings were observed for elderly patients and those hospitalized with COVID-19 pneumonia. CONCLUSIONS: This evidence builds on what has been learned from randomized controlled trials from the pandemic era to inform clinical practices. Remdesivir was associated with significant reduction in mortality for hospitalized patients including the elderly and those with COVID-19 pneumonia.

BACKGROUND: Patients with immunocompromising conditions are at increased risk for coronavirus disease 2019 (COVID-19)-related hospitalizations and deaths. Randomized clinical trials provide limited enrollment, if any, to provide information on the outcomes in such patients treated with remdesivir. METHODS: Using the US PINC AI Healthcare Database, we identified adult patients with immunocompromising conditions, hospitalized for COVID-19 between December 2021 and February 2024. The primary outcome was all-cause inpatient mortality examined in propensity score-matched patients in remdesivir vs nonremdesivir groups. Subgroup analyses were performed for patients with cancer, hematological malignancies, and solid organ or hematopoietic stem cell transplant recipients. RESULTS: Of 28 966 patients included in the study, 16 730 (58%) received remdesivir during the first 2 days of hospitalization. After propensity score matching, 8822 patients in the remdesivir and 8822 patients in the nonremdesivir group were analyzed. Remdesivir was associated with a significantly lower mortality rate among patients with no supplemental oxygen (adjusted hazard ratio [95% confidence interval], 0.73 [.62-.86] at 14 days and 0.79 [.68-.91] at 28 days) and among those with supplemental oxygen (0.75 [.67-.85] and 0.78 [.70-.86], respectively). Remdesivir was also associated with lower mortality rates in subgroups of patients with cancer, hematological malignancies (leukemia, lymphoma, or multiple myeloma), and solid organ or hematopoietic stem cell transplants. CONCLUSIONS: In this large cohort of patients with immunocompromising conditions hospitalized for COVID-19, remdesivir was associated with significant improvement in survival, including patients with varied underlying immunocompromising conditions. The integration of current real-world evidence into clinical guideline recommendations can inform clinical communities to optimize treatment decisions in the evolving COVID-19 era, extending beyond the conclusion of the public health emergency declaration.

SARS-CoV-2 can infect cells through endocytic uptake, a process that is targeted by inhibition of lysosomal proteases. However, clinically this approach to treat viral infections has afforded mixed results, with some studies detailing an oral regimen of hydroxychloroquine accompanied by significant off-target toxicities. We rationalized that an organelle-targeted approach will avoid toxicity while increasing the concentration of the drug at the target. Here, we describe a lysosome-targeted, mefloquine-loaded poly(glycerol monostearate-co-ε-caprolactone) nanoparticle (MFQ-NP) for pulmonary delivery via inhalation. Mefloquine is a more effective inhibitor of viral endocytosis than hydroxychloroquine in cellular models of COVID-19. MFQ-NPs are less toxic than molecular mefloquine, are 100-150 nm in diameter, and possess a negative surface charge, which facilitates uptake via endocytosis allowing inhibition of lysosomal proteases. MFQ-NPs inhibit coronavirus infection in mouse MHV-A59 and human OC43 coronavirus model systems and inhibit SARS-CoV-2 WA1 and its Omicron variant in a human lung epithelium model. Organelle-targeted delivery is an effective means to inhibit viral infection.

Cellular nanoparticles (CNPs), which refer to nanoparticles coated with natural cell membranes, are promising for neutralizing pathological agents. Here, we use CNPs as a medical countermeasure against the infection of SARS-CoV-2 variants in an animal model. CNPs comprise polymeric cores coated with the plasma membranes of human macrophages. The resulting nanoparticles (MΦ-NPs) act as host cell decoys to intercept SARS-CoV-2 and block its cellular entry, thus inhibiting subsequent viral infection. Our findings indicate that MΦ-NPs bind to the spike proteins of SARS-CoV-2 variants in a dose-dependent manner and inhibit the infectivity of live viruses. In hamsters infected with SARS-CoV-2 variants, MΦ-NPs significantly reduce the viral burden in the lungs, demonstrating their effectiveness in inhibiting viral infectivity in vivo. Furthermore, MΦ-NPs are primarily taken up by alveolar macrophages without inducing noticeable adverse effects. Given the crucial role of macrophages in viral infections, MΦ-NPs present a promising approach to combating emerging viral threats.

BACKGROUND: Few antiviral therapies have been studied in patients with coronavirus disease 2019 (COVID-19) and kidney impairment. Herein, the efficacy, safety, and pharmacokinetics of remdesivir, its metabolites, and sulfobutylether-β-cyclodextrin excipient were evaluated in hospitalized patients with COVID-19 and severe kidney impairment. METHODS: In REDPINE, a phase 3, randomized, double-blind, placebo-controlled study, participants aged ≥12 years hospitalized for COVID-19 pneumonia with acute kidney injury, chronic kidney disease, or kidney failure were randomized 2:1 to receive intravenous remdesivir (200 mg on day 1; 100 mg daily up to day 5) or placebo (enrollment from March 2021 to March 2022). The primary efficacy end point was the composite of the all-cause mortality rate or invasive mechanical ventilation rate through day 29. Safety was evaluated through day 60. RESULTS: Although enrollment concluded early, 243 participants were enrolled and treated (remdesivir, n = 163; placebo, n = 80). At baseline, 90 participants (37.0%) had acute kidney injury (remdesivir, n = 60; placebo, n = 30), 64 (26.3%) had chronic kidney disease (remdesivir, n = 44; placebo, n = 20), and 89 (36.6%) had kidney failure (remdesivir, n = 59; placebo, n = 30); and 31 (12.8%) were vaccinated against COVID-19. Composite all-cause mortality or invasive mechanical ventilation rates through day 29 were 29.4% and 32.5% in the remdesivir and placebo group, respectively (P = .61). Treatment-emergent adverse events were reported in 80.4% for remdesivir versus 77.5% for placebo, and serious adverse events in 50.3% versus 50.0%, respectively. Pharmacokinetic plasma exposure to remdesivir was not affected by kidney function. CONCLUSIONS: Although the study was underpowered, no significant difference in efficacy was observed between treatment groups. REDPINE demonstrated that remdesivir is safe in patients with COVID-19 and severe kidney impairment. CLINICAL TRIALS REGISTRATION: EudraCT 2020-005416-22; Clinical Trials.gov NCT04745351.

ObjectivesThe aim of this study was to prospectively evaluate in a randomized, triple-masked, placebo-controlled trial, outcomes for kittens with ocular manifestations of infectious upper respiratory disease (IURD) treated with an ophthalmic and oral antibiotic only vs those also treated with famciclovir.MethodsKittens were stratified into three age (1 to

Oral broad-spectrum antivirals are urgently needed for the treatment of many emerging and contemporary RNA viruses. We previously synthesized 1-O-octadecyl-2-O-benzyl-sn-glyceryl-P-RVn (ODBG-P-RVn, V2043), a phospholipid prodrug of GS-441524 (remdesivir nucleoside, RVn), and demonstrated its in vivo efficacy in a SARS-CoV-2 mouse model. Structure-activity relationship studies focusing on the prodrug scaffold identified two modifications, 3-fluoro-4-methoxy-benzyl (V2053) and 4-cyano-benzyl (V2067), that significantly enhanced the in vitro broad-spectrum antiviral activity against multiple RNA viruses when compared to V2043. Here, we demonstrate that V2043, V2053, and V2067 are all orally bioavailable, well-tolerated, and achieve high sustained plasma levels after single oral daily dosing. All three phospholipid prodrugs are significantly more active than RVn in vitro and significantly reduce SARS-CoV-2 lung titers in prophylaxis and treatment mouse models of SARS-CoV-2 B.1.351 infection. On a molar basis, V2043 and V2067 are substantially more active than obeldesivir/GS-5245 and molnupiravir in vivo. Together, these data support the continued development of phospholipid RVn prodrugs for the treatment of SARS-CoV-2 and other RNA viruses of clinical concern.

BACKGROUND: Although antivirals remain important for the treatment COVID-19, methods to assess treatment efficacy are lacking. Here, we investigated the impact of remdesivir on viral dynamics and their contribution to understanding antiviral efficacy in the multicenter Adaptive COVID-19 Treatment Trial 1, which randomized patients to remdesivir or placebo. METHODS: Longitudinal specimens collected during hospitalization from a substudy of 642 patients with COVID-19 were measured for viral RNA (upper respiratory tract and plasma), viral nucleocapsid antigen (serum), and host immunologic markers. Associations with clinical outcomes and response to therapy were assessed. RESULTS: Higher baseline plasma viral loads were associated with poorer clinical outcomes, and decreases in viral RNA and antigen in blood but not the upper respiratory tract correlated with enhanced benefit from remdesivir. The treatment effect of remdesivir was most pronounced in patients with elevated baseline nucleocapsid antigen levels: the recovery rate ratio was 1.95 (95% CI, 1.40-2.71) for levels >245 pg/mL vs 1.04 (95% CI, .76-1.42) for levels

Background and aimsSecond-generation direct-acting antivirals (2G DAA) to cure HCV have led to dramatic clinical improvements. HCV-associated hepatocellular carcinoma (HCC), however, remains common. Impaired immune tumor surveillance may play a role in HCC development. Our cohort evaluated the effects of innate immune types and clinical variables on outcomes including HCC.MethodsParticipants underwent full HLA class I/KIR typing and long-term HCV follow-up.ResultsA total of 353 HCV+ participants were followed for a mean of 7 years. Cirrhosis: 25% at baseline, developed in 12% during follow-up. 158 participants received 2G DAA therapy. HCC developed without HCV therapy in 20 subjects, 24 HCC after HCV therapy, and 10 of these after 2G DAA. Two predictors of HCC among 2G DAA-treated patients: cirrhosis (OR, 10.0, p = 0.002) and HLA/KIR profiles predicting weak natural killer (NK) cell-mediated immunity (NK cell complementation groups 6, 9, 11, 12, OR of 5.1, p = 0.02). Without 2G DAA therapy: cirrhosis was the main clinical predictor of HCC (OR, 30.8, p < 0.0001), and weak NK-cell-mediated immunity did not predict HCC.ConclusionCirrhosis is the main risk state predisposing to HCC, but weak NK-cell-mediated immunity may predispose to post-2G DAA HCC more than intermediate or strong NK-cell-mediated immunity.

ImpactFindings from this study provide further reassuring evidence that infant exposure through human milk received from lactating individuals who require treatment with remdesivir is negligible.

We present a novel small molecule antiviral chemotype that was identified by an unconventional cell-free protein synthesis and assembly-based phenotypic screen for modulation of viral capsid assembly. Activity of PAV-431, a representative compound from the series, has been validated against infectious viruses in multiple cell culture models for all six families of viruses causing most respiratory diseases in humans. In animals, this chemotype has been demonstrated efficacious for porcine epidemic diarrhoea virus (a coronavirus) and respiratory syncytial virus (a paramyxovirus). PAV-431 is shown to bind to the protein 14-3-3, a known allosteric modulator. However, it only appears to target the small subset of 14-3-3 which is present in a dynamic multi-protein complex whose components include proteins implicated in viral life cycles and in innate immunity. The composition of this target multi-protein complex appears to be modified upon viral infection and largely restored by PAV-431 treatment. An advanced analog, PAV-104, is shown to be selective for the virally modified target, thereby avoiding host toxicity. Our findings suggest a new paradigm for understanding, and drugging, the host-virus interface, which leads to a new clinical therapeutic strategy for treatment of respiratory viral disease.

Paritaprevir is an orally bioavailable, macrocyclic drug used for treating chronic Hepatitis C virus (HCV) infection. Its structures have been elusive to the public until recently when one of the crystal forms is solved by microcrystal electron diffraction (MicroED). In this work, the MicroED structures of two distinct polymorphic crystal forms of paritaprevir are reported from the same experiment. The different polymorphs show conformational changes in the macrocyclic core, as well as the cyclopropyl sulfonamide and methyl pyrazinamide substituents. Molecular docking shows that one of the conformations fits well into the active site pocket of the HCV non-structural 3/4A (NS3/4A) serine protease target, and can interact with the pocket and catalytic triad via hydrophobic interactions and hydrogen bonds. These results can provide further insight for optimization of the binding of acyl sulfonamide inhibitors to the HCV NS3/4A serine protease. In addition, this also demonstrates the opportunity to derive different polymorphs and distinct macrocycle conformations from the same experiments using MicroED.

Here, an in vitro characterization of a family of prazole derivatives that covalently bind to the C73 site on Tsg101 and assay their ability to inhibit viral particle production is presented. Structurally, increased steric bulk on the 4-pyridyl of the prazole expands the prazole site on the UEV domain toward the β-hairpin in the Ub-binding site and is coupled to increased inhibition of virus-like particle production in HIV-1. Increased bulk also increased toxicity, which is alleviated by increasing flexibility. Further, the formation of a novel secondary Tsg101 adduct for several of the tested compounds and the commercial drug lansoprazole. The secondary adduct involved the loss of the 4-pyridyl substituent to form an irreversible species, with implications for increasing the half-life of the active species or its specificity toward Tsg101 UEV. It is also determined that sulfide derivatives display effective viral inhibition, presumably through cellular sulfoxidation, allowing for delayed conversion within the cellular environment, and identify SARS-COV-2 as a target of prazole inhibition. These results open multiple avenues for the design of prazole derivatives for antiviral applications.

The ongoing evolution of SARS-CoV-2 to evade vaccines and therapeutics underlines the need for innovative therapies with high genetic barriers to resistance. Therefore, there is pronounced interest in identifying new pharmacological targets in the SARS-CoV-2 viral life cycle. The small molecule PAV-104, identified through a cell-free protein synthesis and assembly screen, was recently shown to target host protein assembly machinery in a manner specific to viral assembly. In this study, we investigate the capacity of PAV-104 to inhibit SARS-CoV-2 replication in human airway epithelial cells (AECs). We show that PAV-104 inhibits >99% of infection with diverse SARS-CoV-2 variants in immortalized AECs, and in primary human AECs cultured at the air-liquid interface (ALI) to represent the lung microenvironment in vivo. Our data demonstrate that PAV-104 inhibits SARS-CoV-2 production without affecting viral entry, mRNA transcription, or protein synthesis. PAV-104 interacts with SARS-CoV-2 nucleocapsid (N) and interferes with its oligomerization, blocking particle assembly. Transcriptomic analysis reveals that PAV-104 reverses SARS-CoV-2 induction of the type-I interferon response and the maturation of nucleoprotein signaling pathway known to support coronavirus replication. Our findings suggest that PAV-104 is a promising therapeutic candidate for COVID-19 with a mechanism of action that is distinct from existing clinical management approaches.

BackgroundAn ongoing important need exists to rapidly develop novel therapeutics for COVID-19 that will retain antiviral efficacy in the setting of rapidly evolving SARS-CoV-2 variants and potential future development of resistance of SARS-COV-2 to remdesivir and protease inhibitors. To date, there is no FDA-approved treatment for post-exposure prophylaxis against SAR-CoV-2. We have shown that the mitochondrial antioxidant mitoquinone/mitoquinol mesylate (Mito-MES), a dietary supplement, has antiviral activity against SARS-CoV-2 in vitro and in SARS-CoV-2 infected K18-hACE2 mice.MethodsIn this exploratory, pragmatic open label clinical trial (ClinicalTrials.gov identifier NCT05381454), we studied whether Mito-MES is an effective post-exposure prophylaxis treatment in people who had high-grade unmasked exposures to SARS-CoV-2 within 5 days prior to study entry. Participants were enrolled in real-world setting in Los Angeles, United States between May 1 and December 1, 2022 and were assigned to either mito-MES 20 mg daily for 14 days (n = 40) or no mito-MES (controls) (n = 40). The primary endpoint was development of SARS-CoV-2 infection based on 4 COVID-19 diagnostic tests [rapid antigen tests (RATs) or PCR] performed during the study period (14 days post exposure).FindingsOut of 40 (23 females; 57.5%) study participants who took Mito-MES, 12 (30%) developed SARS-CoV-2 infection compared to 30 of the 40 controls (75%) (difference -45.0%, 95% confidence intervals (CI): -64.5%, -25.5%). Out of 40 (19 females; 47.5%) study participants in the control group, 30 (75.0%) had at least one positive COVID-19 diagnostic test and 23 (57.5%) were symptomatic. With regards to key secondary outcomes, among symptomatic SARS-CoV-2 infections, the median duration of viral symptoms was lower in the Mito-MES group (median 3.0, 95% CI 2.75, 3.25) compared to the control group (median 5.0, 95% CI 4.0, 7.0). None of the study participants was hospitalized or required oxygen therapy. Mito-MES was well tolerated and no serious side effect was reported in any study participant.InterpretationThis work describes antiviral activity of mito-MES in humans. Mito-MES was well tolerated in our study population and attenuated transmission of SARS-CoV-2 infection. Given established safety of Mito-MES in humans, our results suggest that randomized control clinical trials of Mito-MES as post-exposure prophylaxis against SARS-CoV-2 infection are warranted.FundingThis work was supported in part by National Institutes of Health grant R01AG059501 (TK), National Institutes of Health grant R01AG059502 04S1 (TK), NIH/National Center for Advancing Translational Sciences (NCATS) UCLA CTSI Grant Number UL1TR001881 and California HIV/AIDS Research Program grant OS17-LA-002 (TK).

A clear understanding of real-world uptake of nirmatrelvir-ritonavir for treatment of SARS-CoV-2 can inform treatment allocation strategies and improve interpretation of effectiveness studies. We used data from a large US healthcare system to describe nirmatrelvir-ritonavir dispenses among all SARS-CoV-2 positive patients aged ≥ 12 years meeting recommended National Institutes of Health treatment eligibility criteria for the study period between 1 January and 31 December, 2022. Overall, 10.9% (N = 34,791/319,900) of treatment eligible patients with SARS-CoV-2 infections received nirmatrelvir-ritonavir over the study period. Although uptake of nirmatrelvir-ritonavir increased over time, by the end of 2022, less than a quarter of treatment eligible patients with SARS-CoV-2 infections had received nirmatrelvir-ritonavir. Across patient demographics, treatment was generally consistent with tiered treatment guidelines, with dispenses concentrated among patients aged ≥ 65 years (14,706/63,921; 23.0%), and with multiple comorbidities (10,989/54,431; 20.1%). However, neighborhoods of lower socioeconomic status (upper third of neighborhood deprivation index [NDI]) had between 12% (95% CI: 7-18%) and 28% (25-32%) lower odds of treatment dispense over the time periods studied compared to the lower third of NDI distribution, even after accounting for demographic and clinical characteristics. A limited chart review (N = 40) confirmed that in some cases a decision not to treat was appropriate and aligned with national guidelines to use clinical judgement on a case-by-case basis. There is a need to enhance patient and provider awareness on the availability and benefits of nirmatrelvir-ritonavir for the treatment of COVID-19 illness.

Reporting in Nature Communications, Huo and colleagues provide three-dimensional structures of a bacterial immune defense system called Gabija. This work builds on recently published structural and functional studies and contributes strong evidence that protein assembly formation is essential for antiviral function.

BACKGROUND: Since November 2019, the SARS-CoV-2 pandemic has created challenges for preventing and managing COVID-19 in children and adolescents. Most research to develop new therapeutic interventions or to repurpose existing ones has been undertaken in adults, and although most cases of infection in pediatric populations are mild, there have been many cases of critical and fatal infection. Understanding the risk factors for severe illness and the evidence for safety, efficacy, and effectiveness of therapies for COVID-19 in children is necessary to optimize therapy. METHODS: A panel of experts in pediatric infectious diseases, pediatric infectious diseases pharmacology, and pediatric intensive care medicine from 21 geographically diverse North American institutions was re-convened. Through a series of teleconferences and web-based surveys and a systematic review with meta-analysis of data for risk factors, a guidance statement comprising a series of recommendations for risk stratification, treatment, and prevention of COVID-19 was developed and refined based on expert consensus. RESULTS: There are identifiable clinical characteristics that enable risk stratification for patients at risk for severe COVID-19. These risk factors can be used to guide the treatment of hospitalized and non-hospitalized children and adolescents with COVID-19 and to guide preventative therapy where options remain available.

OBJECTIVES: Although guidelines recommend antiviral therapy for outpatients with COVID-19 who are at high risk of progressing to severe conditions, such as older adults, many patients do not receive appropriate treatment. Little is known, however, about the physician factors associated with the prescription of guideline-recommended antiviral therapy for patients with COVID-19. DESIGN: A cross-sectional study. SETTING: Data including outpatient visits in primary care clinics in Japan from April to August 2023. PARTICIPANTS: We analysed 30 953 outpatients aged ≥65 years treated with COVID-19 (mean (SD) age, 75.0 (7.6) years; 17 652 women (57.0%)) in 1394 primary care clinics. OUTCOME MEASURES: The primary outcome was the prescription of guideline-recommended antivirals (ie, nirmatrelvir-ritonavir or molnupiravir), adjusted for patient characteristics, months of visits and regions. RESULTS: Antiviral prescriptions were concentrated among a small proportion of physicians; for example, the top 10% of physicians that had the largest number of nirmatrelvir-ritonavir prescriptions accounted for 92.4% of all nirmatrelvir-ritonavir prescriptions. After adjusting for potential confounders, physicians with higher patient volumes were more likely to prescribe guideline-recommended antivirals to their patients (adjusted OR (aOR) for high vs low volume, 1.76; 95% CI 1.31 to 2.38; adjusted p

BACKGROUND: The ACTT risk profile, which was developed from ACTT-1 (Adaptive COVID-19 Treatment Trial-1), demonstrated that hospitalized patients with COVID-19 in the high-risk quartile (characterized by low absolute lymphocyte count [ALC], high absolute neutrophil count [ANC], and low platelet count at baseline) benefited most from treatment with the antiviral remdesivir. It is unknown which patient characteristics are associated with benefit from treatment with the immunomodulator baricitinib. OBJECTIVE: To apply the ACTT risk profile to the ACTT-2 cohort to investigate potential baricitinib-related treatment effects by risk quartile. DESIGN: Post hoc analysis of ACTT-2, a randomized, double-blind, placebo-controlled trial. (ClinicalTrials.gov: NCT04401579). SETTING: Sixty-seven trial sites in 8 countries. PARTICIPANTS: Adults hospitalized with COVID-19 (n = 999; 85% U.S. participants). INTERVENTION: Baricitinib+remdesivir versus placebo+remdesivir. MEASUREMENTS: Mortality, progression to invasive mechanical ventilation (IMV) or death, and recovery, all within 28 days; ALC, ANC, and platelet count trajectories. RESULTS: In the high-risk quartile, baricitinib+remdesivir was associated with reduced risk for death (hazard ratio [HR], 0.38 [95% CI, 0.16 to 0.86]; P = 0.020), decreased progression to IMV or death (HR, 0.57 [CI, 0.35 to 0.93]; P = 0.024), and improved recovery rate (HR, 1.53 [CI, 1.16 to 2.02]; P = 0.002) compared with placebo+remdesivir. After 5 days, participants receiving baricitinib+remdesivir had significantly larger increases in ALC and significantly larger decreases in ANC compared with control participants, with the largest effects observed in the high-risk quartile. LIMITATION: Secondary analysis of data collected before circulation of current SARS-CoV-2 variants. CONCLUSION: The ACTT risk profile identifies a subgroup of hospitalized patients who benefit most from baricitinib treatment and captures a patient phenotype of treatment response to an immunomodulator and an antiviral. Changes in ALC and ANC trajectory suggest a mechanism whereby an immunomodulator limits severe COVID-19. PRIMARY FUNDING SOURCE: National Institute of Allergy and Infectious Diseases.

With current treatments addressing only a fraction of pathogens and new viral threats constantly evolving, there is a critical need to expand our existing therapeutic arsenal. To speed the rate of discovery and better prepare against future threats, we establish a high-throughput platform capable of screening compounds against 40 diverse viral proteases simultaneously. This multiplex approach is enabled by using cellular biosensors of viral protease activity combined with DNA-barcoding technology, as well as several design innovations that increase assay sensitivity and correct for plate-to-plate variation. Among >100,000 compound-target interactions explored within our initial screen, a series of broad-acting inhibitors against coronavirus proteases were uncovered and validated through orthogonal assays. A medicinal chemistry campaign was performed to improve one of the inhibitor's potency while maintaining its broad activity. This work highlights the power of multiplex screening to efficiently explore chemical space at a fraction of the time and costs of previous approaches. Synopsis: A multiplex drug screening platform with cellular biosensors identifies antivirals against 40 diverse viruses simultaneously. In a screen of more than 100,000 compound-target interactions, broad-acting CoV protease inhibitors were discovered and validated. Multiplexed drug screening can accelerate antiviral discovery, delivering results with less time, effort, and resources compared to traditional single-target methods. A platform built on cellular biosensors capable of detecting antiviral activity against 40 distinct viral proteases from 7 viral families, was used to probe 106,640 model-compound interactions. Among the identified putative protease inhibitors, a series of broad-acting compounds targeting the coronavirus 3CL protease and papain-like protease were validated through biochemical and live virus assays. A multiplex drug screening platform with cellular biosensors identifies antivirals against 40 diverse viruses simultaneously. In a screen of more than 100,000 compound-target interactions, broad-acting CoV protease inhibitors were discovered and validated. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) have gained significant attention in veterinary medicine due to their antimicrobial properties and potential therapeutic applications. Silver has long been recognized for its ability to combat a wide range of pathogens, and when engineered at the nanoscale, silver's surface area and reactivity are greatly enhanced, making it highly effective against bacteria, viruses, and fungi. This narrative review aimed to summarize the evidence on the antimicrobial properties of AgNPs and their current and potential clinical applications in veterinary medicine. The antimicrobial action of AgNPs involves several mechanisms, including, among others, the release of silver ions, disruption of cell membranes and envelopes, induction of oxidative stress, inhibition of pathogens' replication, and DNA damage. Their size, shape, surface charge, and concentration influence their efficacy against bacteria, viruses, and fungi. As a result, the use of AgNPs has been explored in animals for infection prevention and treatment in some areas, such as wound care, coating of surgical implants, animal reproduction, and airway infections. They have also shown promise in preventing biofilm formation, a major challenge in treating chronic bacterial infections. Additionally, AgNPs have been studied for their potential use in animal feed as a supplement to enhance animal health and growth. Research suggested that AgNPs could stimulate immune responses and improve the gut microbiota of livestock, potentially reducing the need for antibiotics in animal husbandry. Despite their promising applications, further research is necessary to fully understand the safety, efficacy, and long-term effects of AgNPs on animals, humans, and the environment. [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC) ranks sixth amongst all cancers and is the 2nd top cause of mortality attributable to cancer. Aim of the work: This study aimed to ascertain the sustained virological response (SVR) to interferon-free regimens in chronic people with HCV after the successful treatment of hepatocellular carcinoma, as well as the percentage of persons who would demonstrate any radiological or laboratory alterations indicating a local or de novo recurrence of HCC. Patients and methods: This trial was carried out on 90 Egyptian persons with chronic HCV infection who were eligible for treatment with oral antiviral agents (DAAs) with hepatic focal lesion(s). Patients were referred to from both the outpatient clinic and hepatocellular carcinoma clinic at the National Hepatology and Tropical Medicine Research Institute (NHTMRI), and the trial was conducted in the period between October 2017 and May 2021. Results: Four patients with distant metastasis, three dying from liver-related incidents, received surgical resection, TACE, and RFA treatment, while one patient survived with compensated chronic liver disease. By multivariate logistic regression, we found that AFP is an independent predictor of HCC recurrence, while baseline urea level and FIB4 before antiviral therapy protect against recurrence. PLT was the best predictor, with AFP having a sensitivity of 52% and specificity of 93.8% at a cutoff value of 135 and PCR having a sensitivity of 72%. Conclusion: The HCC recurrence rate was 27.8%, slightly higher than the estimated annual HCC recurrence rate following curative procedures (20%). [ABSTRACT FROM AUTHOR]

Background and objective: This study aims to understand the reasons people avoid or delay HCV treatment and identify potential pathways that can increase the uptake of HCV treatment from a health systems perspective. Methods: Semi-structured interviews with 15 participants who were HCV positive and had a history of active or recent injecting drug use were conducted. Thematic and framework analyses based on an integrated framework by Høj and colleagues were used to identify barriers and opportunities to HCV treatment. Results: The study identified barriers and enablers to HCV treatment at individual, socio-structural, and system levels. Competing priorities, unstable housing, and stigma were barriers, while engagement in opioid agonist therapy and peer support were enablers. Misinformation, limited OAT prescribers, and gaps in care coordination, especially within the prison system, were identified as missed opportunities at the system level, while organizational support and respectful relationships with service providers were key to engagement. Conclusions: Person-centered care addressing the specific needs of PWID, such as housing, and drug and alcohol treatment, should be enhanced, and HCV care embedded within these services. Strengthening care pathways, especially within and between prisons and other primary care services, is urgently needed. [ABSTRACT FROM AUTHOR]

AbstractAlthough COVID-19 is now becoming endemic, SARS-CoV-2 persists potential jeopardy to clinically vulnerable populations. Hence, further study is still necessary to discover novel antiviral agents against SARS-CoV-2 for proactive preparedness. SARS-CoV-2 papain-like protease (PL Pro) is a target enzyme for searching anti-Covid candidates. Our prior study revealed the major formation of inclusion bodies during PL Pro expression in E. coli RIPL. In this study, we tried using chaperonin in the E. coli Arctic Express system and both codon optimization and maltose-binding protein (MBP) fusion protein to make PL Pro more soluble. Recombinant PL Pro encoded on the pET21d(+) plasmid was expressed in E. coli Arctic express. However, the soluble protein yield remained low and unstable due to suboptimal codon usage in the insert gene. Whereas, fusion of the MBP protein with optimized codon of PL Pro enhanced the enzyme expression and solubility. Recombinant PL Pro cleaved the linker between MBP and PL Pro, which served as a cleavage site recognized by PL Pro (LKGG↓A). The purified enzyme from a 200-mL culture generated 1 mL of pure PL Pro enzyme at a 1.913 mg/mL concentration. It exhibited favorable activity against the Z-RLRGG-AMC substrate, with a Km value of 33.40 μM and a Vmax of 5.10 RFU/min. [ABSTRACT FROM AUTHOR]

Background: Enterovirus 71 (EV71) is one of the major causative agents of hand, foot, and mouth disease (HFMD), and can cause severe cerebral complications and even fatality in children younger than 5 years old. However, there is no specific medication for EV71 infection in clinical practice. Our previous studies had identified the 6-thioguanine (6-TG), an FDA-approved anticancer drug, as a potential antiviral agent, but its anti-EV71 activity is largely unknown, therefore, we aim to explore the antiviral effect of 6-TG on EV71. Results: 6-TG significantly suppressed EV71 mRNA level, VP1 protein expression, and viral progeny production in HT-29 cells. In EV71-infected HT-29 cells, the 50% cytotoxicity concentration of 6-TG (CC50) was > 2000 µM and the 50% inhibitory concentration of 6-TG against EV71 (IC50) was 0.9302 µM. Interestingly, the selectivity index (SI) value of 6-TG against EV71 was > 2150.1, which was higher than the SI value (> 66.7) of ribavirin. Mechanistically, 6-TG treatment reduced the expression of baculoviral IAP repeat containing 3 (BIRC3), and further inhibited EV71 replication by attenuating BIRC3-mediated the complete autophagy. Conclusions: 6-TG exerted a significant inhibitory effect on EV71 infection in vitro and prevented EV71-induced the complete autophagy by decreasing BIRC3 expression. Our work provided a basis for the further development of 6-TG as a therapy for EV71-associated HFMD. [ABSTRACT FROM AUTHOR]

This study identifies the secondary metabolites from Alternaria alternate and evaluates their ACE-2: Spike RBD (SARS-CoV-2) inhibitory activity confirmed via immunoblotting in human lung microvascular endothelial cells. In addition, their in vitro anti-inflammatory potential was assessed using a cell-based assay in LPS-treated RAW 264.7 macrophage cells. Two novel compounds, altenuline (1), phthalic acid bis (7'/7" pentyloxy) isohexyl ester (2), along with 1-deoxyrubralactone (3) alternariol-5-O-methyl ether (4) and alternariol (5) were identified. Molecular docking and in vitro studies showed that compounds 2 and 4 were promising to counteract SARS-CoV-2 attachment to human ACE-2. Thus, they are considered promising natural anti-viral agents. SwissADME in silico analysis was conducted to predict the drug-like potential. Immunoblotting analysis confirmed that the tested compounds (1–4) demonstrated downregulation of ACE-2 expression in the endothelial cells from the lungs with variable degrees. Furthermore, the tested compounds (1–4) showed promising anti-inflammatory activities through TNF-α: TNFR2 inhibitory activity and their inhibitory effect on the proinflammatory cytokines (TNF-α and IL-6) in LPS-stimulated monocytes. In conclusion, our study, for the first time, provides beneficial experimental confirmation for the efficiency of the A. alternate secondary metabolites for the treatment of COVID-19 as they hinder SARS-CoV-2 infection and lower inflammatory responses initiated by SARS-CoV-2. A. alternate and its metabolites are considered in developing preventative and therapeutic tactics for COVID-19. [ABSTRACT FROM AUTHOR]

The growing number of viral infections and viral strains from year to year requires the creation of new, more effective antiviral drugs. One of the cost-effective ways to increase drug efficiency is the development of delivery systems for already known and clinically used drugs in order to overcome the challenges currently limiting their efficiency. This review presents the current status of silicon-based particles in this area. Silicon-based materials consist mainly of silicon and its compounds and can contain other inorganic oxides, i.e. are inorganic in nature. Their inorganic nature provides a number of advantages over organic materials (e.g. polymers, lipids, micelles, etc.) which are widely proposed and already used for the indicated purpose. This review provides information about the structural features of the silicon-based materials, methods of their preparation. It contains studies showing why and how the particles themselves can serve as antiviral agents or, as carriers, can help overcome the disadvantages of active drugs and increase their antiviral efficacy. The review highlights the enormous potential of silicon-based inorganic particles (pristine or modified with various inorganic and organic species) in the fight against widespread viral infections. [ABSTRACT FROM AUTHOR]