Journal of Virology最新文献

{"title":"Air-liquid interface model for influenza aerosol exposure <i>in vitro</i>.","authors":"Brittany Seibert, C Joaquin Caceres, L Claire Gay, Nishit Shetty, Flavio Cargnin Faccin, Silvia Carnaccini, Matthew S Walters, Linsey C Marr, Anice C Lowen, Daniela S Rajao, Daniel R Perez","doi":"10.1128/jvi.00619-25","DOIUrl":"10.1128/jvi.00619-25","url":null,"abstract":"<p><p>Airborne transmission is an essential mode of infection and spread of influenza viruses among humans. However, most studies use liquid inoculum for virus infection. To better replicate natural airborne infections <i>in vitro</i>, we generated a calm-aerosol settling chamber system designed to examine the aerosol infectivity of influenza viruses in different cell types. Aerosol inoculation was characterized for multiple influenza A virus (FLUAV) subtypes, including pandemic 2009 H1N1, seasonal swine H3N2, and avian H9N2, using this exposure system. While each FLUAV strain displayed high infectivity within MDCK cells via liquid inoculation, differences in infectivity were observed during airborne inoculation. This was further observed in recently developed immortalized differentiated human airway epithelial cells (BCi-NS1.1) cultured in an air-liquid interface. The airborne infectious dose 50 for each virus was based on the exposure dose per well. Our findings indicate that this system has the potential to enhance our understanding of the factors influencing influenza transmission via the airborne route. This could be invaluable for conducting risk assessments, potentially reducing the reliance on extensive and costly <i>in vivo</i> animal studies.</p><p><strong>Importance: </strong>This study presents a significant advancement in influenza research by developing a novel <i>in vitro</i> system to assess aerosol infectivity, a crucial aspect of influenza transmission. The system's ability to differentiate between mammalian-adapted and avian-adapted influenza viruses based on their aerosol infectivity offers a valuable tool for pre-screening the pandemic potential of different strains. This could potentially streamline the risk assessment process and inform public health preparedness strategies. Moreover, the system's capacity to examine aerosol infectivity in human airway epithelial cells provides a more relevant model for studying virus-host interactions in natural airborne infections. Overall, this study provides an accessible platform for investigating aerosol infectivity, which could significantly contribute to our understanding of influenza transmission and pandemic preparedness.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0061925"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282172/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144208878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Convergent evolution in nucleocapsid facilitated SARS-CoV-2 adaptation for human infection.","authors":"Kumari G Lokugamage, Yiyang Zhou, R Elias Alvarado, Jessica A Plante, Yani Ahearn, Jennifer Chen, Leah Estes, William Meyers, Jakob Nilsson, Andrew L Routh, David H Walker, Vineet D Menachery, Bryan A Johnson","doi":"10.1128/jvi.02091-24","DOIUrl":"10.1128/jvi.02091-24","url":null,"abstract":"<p><p>During the early stages of the COVID-19 pandemic, several SARS-CoV-2 variants of concern (VOCs) independently acquired mutations in the highly variable 203-205 amino acid region of the nucleocapsid (N) protein including R203K + G204R (found in the Alpha, Gamma, and Omicron variants), R203M (in Delta), and T205I (in Beta). In previous research, we demonstrated that the R203K + G204R mutation significantly enhances SARS-CoV-2 N phosphorylation, which subsequently increases viral fitness and pathogenesis. In this study, we investigated the effects of the R203M and T205I mutations on SARS-CoV-2 infection. Using reverse genetics, we introduced these mutations into the early pandemic Washington-1 (WA-1) strain and observed that both the R203M and T205I mutants enhanced replication and viral fitness. However, unlike the R203K + G204R mutant, the R203M and T205I mutants caused only moderate changes in lung pathology. Notably, each mutation-R203K + G204R, R203M, and T205I-induced distinct patterns of N phosphorylation, which likely contribute to the observed phenotypic differences between the mutants. Interestingly, when bat cells expressing human ACE2 were infected with these mutants, we observed a reduction, rather than an enhancement, in both SARS-CoV-2 replication and N phosphorylation. Collectively, our findings suggest that the R203K + G204R, R203M, and T205I mutations are a result of convergent evolution and reflect how SARS-CoV-2 has adapted for human infection.IMPORTANCEAfter its emergence, SARS-CoV-2 rapidly adapted to human infection, acquiring numerous mutations across its genome. Many of these mutations remain uncharacterized. This study examines a mutational hotspot among SARS-CoV-2 variants: residues 203-205 of the nucleocapsid (N) protein. We demonstrate that three unique mutations identified in this region among variants of concern enhance infection in human cells and animal models while eliciting distinct patterns of N protein phosphorylation. Intriguingly, these same mutations reduce both N protein phosphorylation and viral replication in bat cells. These findings suggest that each mutation represents independent adaptation by variants of concern for human infection. Importantly, this study underscores the critical role of these mutations in facilitating the expansion of SARS-CoV-2 into human populations and highlights the potential for similar mutations to drive future zoonotic coronavirus outbreaks.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0209124"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282136/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144275145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metatranscriptomic detection of rabbit hemorrhagic disease virus 2 in karoro (southern black-backed gulls).","authors":"Stephanie J Waller, Chris N Niebuhr, Jessica A Darnley, Kate McInnes, David Winter, Edward C Holmes, Jemma L Geoghegan","doi":"10.1128/jvi.00781-25","DOIUrl":"10.1128/jvi.00781-25","url":null,"abstract":"","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0078125"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282087/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144553816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the fitness of Epstein-Barr virus following its reactivation.","authors":"Yen-Fu Adam Chen, Bianca Mocanu, Ezgi Akidil, Dagmar Pich, Josef Mautner, Bill Sugden, Wolfgang Hammerschmidt","doi":"10.1128/jvi.00626-25","DOIUrl":"10.1128/jvi.00626-25","url":null,"abstract":"<p><p>Epstein-Barr virus (EBV) is usually maintained latently on passaging in cell culture, as are most herpesviruses <i>in vivo</i>. Its fitness, or its ability to infect and replicate in naïve cells, cannot be ascertained by serially passaging it in host cells because no identified cell line initially supports a productive infection by it. Yet its fitness is critical to EBV's remarkable success as a human pathogen. We have, therefore, developed multiple approaches to assess EBV's fitness upon being reactivated from its familiar state of latency. We established and tested expression plasmids for 77 viral genes and a set of shRNAs targeting 25 viral genes to measure how increasing and decreasing their levels affected the fitness of the released stocks of virus. Four of their properties were then analyzed: (i) their concentrations of physical particles, (ii) their binding to the CD21 receptor on a B-cell line, (iii) their entry into human primary B cells, and (iv) their infectious titers. These analyses identified multiple EBV genes whose altered levels of expression altered the biological activities of the released virus. These measurements revealed, though, an unexpected insight into the robustness of EBV produced from latently infected cells. EBV is amazingly resilient to any increased expression of its genes. The levels expressed in cells, as they support an induced productive infection, therefore are close to optimal for the fitness of the released virus.IMPORTANCEPopulations of viruses accumulate mutations while being propagated. While most mutations are neutral or disadvantageous, some confer on the variant a selective advantage, increasing its infectivity. These variants can be identified by serial passaging virus stocks, allowing those with increased fitness to predominate. This approach does not work for Epstein-Barr virus (EBV), for which no identified cell line initially supports its productive infection. How mutations accumulate in EBV as it is propagated latently to affect its fitness was unknown. We have devised an approach to assess EBV's fitness upon being reactivated. Our findings suggest that EBV during its many latent generations has maintained a strikingly robust productive fitness.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0062625"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282151/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat shock protein 90 chaperone activity is required for hepatitis A virus replication.","authors":"You Li, Xin Zheng, Ling Xie, Maryna Kapustina, Takayoshi Shirasaki, Bryan Yonish, Xian Chen, Asuka Hirai-Yuki, Noriyo Nagata, Ryosuke Suzuki, Masanori Isogawa, Matthew R Vogt, Masamichi Muramatsu, Stanley M Lemon","doi":"10.1128/jvi.00502-25","DOIUrl":"10.1128/jvi.00502-25","url":null,"abstract":"<p><p>HSP90 heat shock chaperones are essential for maintaining cellular proteostasis, as well as the ATP-dependent folding and functional maturation of many viral proteins. As a result, inhibitors of HSP90 have broad antiviral activity, disrupting replication of many viruses at concentrations below those causing cytotoxicity. Among the <i>Picornaviridae</i>, HSP90 inhibitors block replication of multiple <i>Enterovirus</i>, <i>Aphthovirus,</i> and <i>Cardiovirus</i> species, in some cases, by preventing post-translational processing and assembly of P1 capsid proteins. Hepatitis A virus (HAV), classified within the genus <i>Hepatovirus</i>, has been suggested to be an exception among picornaviruses and to replicate independently of HSP90, possibly because its slow translational kinetics could facilitate co-translational folding and assembly of its capsid proteins. However, we show here that HAV replication is highly dependent upon HSP90, both in human hepatocyte-derived cell lines, in which the 50% inhibitory concentration of geldanamycin was 8.7-11.8 nM, and <i>in vivo</i> in <i>Ifnar1^-/-</i> mice. Label-free proteomics experiments suggested that HSP90 interacts with capsid proteins or their precursors and may thus facilitate the folding and assembly of capsid proteins, as it does for enteroviruses and aphthoviruses. By contrast, there was no evidence for HSP90 interacting with any nonstructural protein, and HSP90 inhibitors did not impair 3C^pro proteolytic activity. Despite this, and in contrast to previous studies of enteroviruses and aphthoviruses, geldanamycin potently inhibited replication of a subgenomic HAV replicon. We conclude that HAV is no exception from the HSP90-dependent nature of other picornaviruses and indeed is more dependent on HSP90 than other picornaviruses for amplification of its genome.IMPORTANCEHepatitis A virus (HAV), a common cause of acute infectious hepatitis, has been reported to differ from other picornaviruses in not requiring heat shock protein HSP90 for efficient replication. However, we show here that productive HAV infection is highly dependent on HSP90 and that HAV replication is potently blocked both in cell culture and <i>in vivo</i> in the murine liver by chemical inhibitors of HSP90. Such inhibitors also disrupt the replication of a subgenomic HAV RNA replicon, indicating that HSP90 is required for the assembly of functional replication organelles. This highlights a key difference from other picornaviruses for which HSP90 is required primarily, if not exclusively, for the maturation of the P1 capsid proteins.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0050225"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282101/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144225796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Syndecan 2 proteoglycan serves as a hepatitis B virus cell attachment receptor.","authors":"Sachin Kumar Tripathi, Yingying Li, Guangxiang Luo","doi":"10.1128/jvi.00796-25","DOIUrl":"10.1128/jvi.00796-25","url":null,"abstract":"<p><p>We have previously found that human apolipoprotein E (apoE) is enriched on the envelope of infectious hepatitis B virus (HBV) and plays an important role in HBV infection and morphogenesis. Recently, we have demonstrated that the low-density lipoprotein receptor (LDLR) is required for efficient HBV infection. LDLR is a known apoE-binding receptor. Additionally, heparan sulfate proteoglycans (HSPGs) serve as apoE-binding receptors. HSPGs are implicated in HBV infection as HBV cell attachment receptors. HSPGs are composed of heparan sulfate glycosaminoglycans covalently attached to core proteins, including syndecans (SDC1-SDC4) and glypicans (GPC1-GPC6). GPC5 was previously reported as an HBV entry-promoting factor. In the present study, we have identified SDC2 as another cell attachment receptor promoting HBV infection. Small interfering RNA (siRNA)-induced silencing of SDC2 expression resulted in a significant reduction of HBV infection. Likewise, SDC2 gene knockout decreased the susceptibility of hepatocytes to HBV infection. However, the defective HBV infection in the SDC2-deficient hepatocytes could be fully restored by ectopic SDC2 expression. The importance of SDC2 in HBV infection was validated using primary human hepatocytes. Moreover, SDC2 deficiency lowered preS1- and apoE-binding and consequently HBV attachment to the surface of hepatocytes. Collectively, our findings suggest that SDC2 functions as an HBV cell attachment receptor.IMPORTANCEMany different DNA and RNA viruses use HSPGs as cell attachment receptors. HSPGs are composed of core proteins and covalently attached heparan sulfate glycosaminoglycans. Individual SDCs and GPCs play distinct roles in the mediation of cell attachment of different viruses. GPC5 was previously found to promote HBV infection. However, the role of SDCs in HBV infection has not been experimentally examined. In the present study, we have identified SDC2 as an HBV cell attachment receptor. We further found that SDC2-deficient hepatocytes are much less susceptible to preS1- and apoE-binding. These findings suggest that SDC2 promote HBV infection likely through interactions with apoE and preS1, both of which are present on the surface of HBV envelope and contain HSPG-binding sites.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0079625"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282149/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144497457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SARS-CoV-2 infection enhancement by amphotericin B: implications for disease management.","authors":"Dung Nguyen, Stephen M Laidlaw, Xiaofeng Dong, Matthew Wand, Amanda Horton, Mark Sutton, Julia Tree, Rachel Milligan, Maximillian Erdmann, David Matthews, Andrew D Davidson, Khondaker Miraz Rahman, Julian A Hiscox, Miles Carroll","doi":"10.1128/jvi.00519-25","DOIUrl":"10.1128/jvi.00519-25","url":null,"abstract":"<p><p>Severe coronavirus disease 2019 (COVID-19) patients who require hospitalization are at high risk of invasive pulmonary mucormycosis. Amphotericin B (AmB), which is the first-line therapy for invasive pulmonary mucormycosis, has been shown to promote or inhibit replication of a spectrum of viruses. In this study, we first predicted that AmB and nystatin had strong interactions with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins using <i>in silico</i> screening, indicative of drugs with potential therapeutic activity against this virus. Subsequently, we investigated the impact of AmB, nystatin, natamycin, fluconazole, and caspofungin on SARS-CoV-2 infection and replication <i>in vitro</i>. Results showed that AmB and nystatin actually increased SARS-CoV-2 replication in Vero E6, Calu-3, and Huh7 cells. At optimal concentrations, AmB and nystatin increase SARS-CoV-2 replication by up to 100- and 10-fold in Vero E6 and Calu-3 cells, respectively. The other antifungals tested had no impact on SARS-CoV-2 infection <i>in vitro</i>. Drug kinetic studies indicate that AmB enhances SARS-CoV-2 infection by promoting viral entry into cells. Additionally, knockdown of genes encoding for interferon-induced transmembrane (IFITM) proteins 1, 2, and 3 suggests AmB enhances SARS-CoV-2 cell entry by overcoming the antiviral effect of the IFITM3 protein. This study further elucidates the role of IFITM3 in viral entry and highlights the potential dangers of treating COVID-19 patients, with invasive pulmonary mucormycosis, using AmB.IMPORTANCEAmB and nystatin are common treatments for fungal infections but were predicted to strongly interact with SARS-CoV-2 proteins, indicating their potential modulation or inhibition against the virus. However, our tests revealed that these antifungals, in fact, enhance SARS-CoV-2 infection by facilitating viral entry into cells. The magnitude of enhancement could be up to 10- or 100-fold, depending on cell lines used. These findings indicate that AmB and nystatin have the potential to enhance disease when given to patients infected with SARS-CoV-2 and therefore should not be used for treatment of fungal infections in active COVID-19 cases.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0051925"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282131/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144216270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of immune checkpoint molecules in PRRSV-2-induced immune modulation: insights from comparative <i>in vivo</i> evaluation including NADC34-like PRRSV.","authors":"Seung-Chai Kim, Hwan-Ju Kim, Sang Chul Kang, Aarif Rasool, Ji-Hyun Ryu, Jung-Min Lee, Won-Il Kim","doi":"10.1128/jvi.02298-24","DOIUrl":"10.1128/jvi.02298-24","url":null,"abstract":"&lt;p&gt;&lt;p&gt;The emergence of genetically diverse PRRSV-2 lineages, including the NADC34-like virus, presents significant challenges to the swine industry due to their variable pathogenicity and impact on immune modulation. However, the precise mechanisms underlying virus-induced immune modulation remain poorly understood. This study investigated the immunopathological characteristics of the Korean NADC34-like PRRSV strain JBNU-22-N01 in comparison with the NADC30-like strain PJ73 and the prototype strain VR2332 in a weaned piglet model. All PRRSV-2 strains exhibited moderate pathogenicity without mortality, following a similar infection course characterized by interstitial pneumonia, cytokine cascades (e.g., IFN-α, IFN-γ, IL-1β, IL-12p40, IL-10, CCL2, CCL5, CCL8, and CXCL10), and upregulation of interferon-stimulated genes [e.g., ISG12(A)]. Flow cytometry analysis revealed significant alterations in the composition of bronchoalveolar lavage (BAL) cell populations, including a decreased frequency of alveolar macrophages and an increased proportion of infiltrating immune cells (monocyte-derived cells, T cells, and NK cells). However, the majority of infiltrated CD4&lt;sup&gt;+&lt;/sup&gt; and CD8&lt;sup&gt;+&lt;/sup&gt; T cells exhibited minimal expression of effector cytokines (e.g., IFN-γ), suggesting a phenotypically naïve-like or functionally unresponsive state. The mRNA expression levels of BAL cells revealed significant upregulation of immune checkpoint molecules (e.g., PD1, PDL1, CTLA4, LAG3, and IDO1), indicating immune regulation potentially mediated through cell-to-cell communication. Notably, IDO1 expression was modestly associated with increased systemic Kyn/Trp ratios, supporting the hypothesis that the kynurenine pathway may contribute to systemic immune modulation during PRRSV infection. From a strain-specific perspective, JBNU-22-N01 displayed a faster replication rate, resulting in an accelerated and heightened infection process with stronger immune responses. It uniquely induced robust expression of immune checkpoint molecules and enhanced IDO1 protein production in bronchoalveolar lavage cells, highlighting the immunomodulatory potential of NADC34-like PRRSV. These findings offer insights into both general and strain-specific immunopathogenesis of PRRSV-2 and support the development of better treatments.IMPORTANCEPorcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen affecting the swine industry; however, its immune-related mechanisms remain incompletely understood. Here, we analyzed how three genetically distinct PRRSV strains, including the globally prevalent NADC34-like strain, interact with the immune system in piglets. Our results showed that PRRSV induces severe lung inflammation accompanied by immune cell infiltration. However, many infiltrating immune cells remained inactive, likely due to increased expression of immune-suppressive molecules. Among these, the enzyme indoleamine 2,3-dioxygenase-1 (IDO1) was notably upregulated,","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0229824"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282115/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144208885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interferon-stimulated gene MCL1 inhibits foot-and-mouth disease virus replication by modulating mitochondrial dynamics and autophagy.","authors":"Aishwarya Mogulothu, Danielle Hickman, Sarah Attreed, Paul Azzinaro, Monica Rodriguez-Calzada, Meike Dittmann, Teresa de Los Santos, Steven Szczepanek, Gisselle N Medina","doi":"10.1128/jvi.00581-25","DOIUrl":"10.1128/jvi.00581-25","url":null,"abstract":"<p><p>Interferons (IFNs) and the IFN-stimulated genes (ISGs) that they induce are effective in reducing the replication of foot and mouth disease virus (FMDV). The use of a high-throughput ISG screen identified the ISG myeloid cell leukemia 1 (MCL1) as an ISG with an antiviral effect against an FMDV replicon system. In this study, we demonstrated that overexpression of MCL1 inhibits FMDV replication by reducing approximately 4 logs of virus titers in porcine cells. We then explored the regulatory pathways associated with MCL1 to determine the specific antiviral mechanisms against FMDV. Our findings indicated that the antiviral mechanism does not involve apoptosis regulation or alterations in cell cycle phase heterogeneity. Analysis of mitochondrial function, through measurement of mitochondrial oxygen consumption rate, demonstrated that overexpression of MCL1 results in increased mitochondrial respiration and ATP production, whereas FMDV infection reduces both processes. Moreover, MCL1 overexpression resulted in elongated mitochondrial morphology, contrasting with the fragmented and punctate morphology observed during FMDV infection. Importantly, these changes in mitochondrial dynamics were independent of MCL1's regulation of mitochondrial calcium flux. We also found that MCL1 overexpression suppresses autophagy, which is known to be necessary for FMDV replication. Our data indicate that MCL1 is a potent antiviral ISG against FMDV and highlight the importance of mitochondrial dynamics and autophagy in FMDV replication.IMPORTANCEIn this study, we have successfully used a high-throughput ISG screening approach to measure the inhibition of FMDV replication using an RNA replicon system for the first time. This screen led to the identification of the potent antiviral effects of a relatively lesser-known ISG called MCL1. Our findings reveal that MCL1 exerts its antiviral functions through the regulation of mitochondrial dynamics and autophagy. Although mitochondrial dynamics are involved in apoptosis, metabolism, redox homeostasis, stress responses, and antiviral signaling, this pathway has not been thoroughly explored in the context of FMDV infection. Further investigation into mitochondrial dynamics may facilitate the development of improved biotherapeutics for FMDV. Additionally, our studies highlight the significance of autophagy, a pathway that is needed by FMDV for replication. Ultimately, a deep understanding of all mechanisms exploited by FMDV may allow for the rational design of novel therapeutics and vaccines to control FMD.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0058125"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282159/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144216267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term serial passaging of SARS-CoV-2 reveals signatures of convergent evolution.","authors":"Charles S P Foster, Gregory J Walker, Tyra Jean, Maureen Wong, Levent Brassil, Sonia R Isaacs, Yonghui Lyu, Stuart Turville, Anthony Kelleher, William D Rawlinson","doi":"10.1128/jvi.00363-25","DOIUrl":"10.1128/jvi.00363-25","url":null,"abstract":"<p><p>Understanding viral evolutionary dynamics is crucial to pandemic responses, prediction of virus adaptation over time, and virus surveillance for public health strategies. Whole-genome sequencing (WGS) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has enabled fine-grained studies of virus evolution in the human population. Serial passaging <i>in vitro</i> offers a complementary controlled environment to investigate the emergence and persistence of genetic variants that may confer selective advantage. In this study, nine virus lineages, including four \"variants of concern\" and three former \"variants under investigation,\" were sampled over ≥33 serial passages (range 33-100) in Vero E6 cells. WGS was used to examine virus evolutionary dynamics and identify key mutations with implications for fitness and/or transmissibility. Viruses accumulated mutations regularly during serial passaging. Many low-frequency variants were lost, but others became fixed, suggesting either <i>in vitro</i> benefits or at least a lack of deleterious effect. Mutations arose convergently both across passage lines and when compared with contemporaneous SARS-CoV-2 clinical sequences. These mutations included some that are hypothesized to drive lineage success through host immune evasion (e.g., S:A67V, S:H655Y). The appearance of these mutations <i>in vitro</i> suggested key mutations can arise convergently even in the absence of a multicellular host immune response through mechanisms other than immune-driven mutation. Such mutations may provide other benefits to the viruses <i>in vitro</i>, or arise stochastically. Our quantitative investigation into SARS-CoV-2 evolutionary dynamics spans the greatest number of serial passages to date and will inform measures to reduce the effects of SARS-CoV-2 infection on the human population.IMPORTANCEThe ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a challenge for long-term public health efforts to minimize the effects of coronavirus disease 2019. Whole-genome sequencing of outbreak cases has enabled global contact tracing efforts and the identification of mutations of concern within the virus' genome. However, complementary approaches are necessary to inform our understanding of virus evolution and clinical outcomes. Here, we charted the evolution of the virus within a controlled cell culture environment, focusing on nine different virus lineages. Our approach demonstrates how SARS-CoV-2 continues to evolve readily <i>in vitro</i>, with changes mirroring those seen in outbreak cases globally. Findings of the study are important for (i) investigating the mechanisms of how mutations arise, (ii) predicting the future evolutionary trajectory of SARS-CoV-2, and (iii) informing treatment and prevention design.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0036325"},"PeriodicalIF":4.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12282192/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144248528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}