Search Results (3,577)

Skeletal muscle loss resulting from traumatic injury, sarcopenia, and myopathies remains a major clinical challenge due to the limited regenerative capacity of adult muscle tissue. This review systematically examines advanced biomedical therapeutic approaches to restoring muscle mass and function, including gene therapy, microRNA, cell-based strategies, and tissue engineering. Key mechanisms of muscle histogenesis and regeneration are discussed, with emphasis on the roles of satellite cells, growth factors (IGF-1, VEGF), and transcriptional regulators. Preclinical studies demonstrate that viral and non-viral delivery of myogenic factors can enhance muscle repair, reduce fibrosis, and improve functional outcomes. However, translation to clinical practice is hindered by challenges such as immune responses, inadequate reinnervation, and the complexity of replicating native tissue architecture. Emerging strategies combining gene delivery with rehabilitation, immunomodulation, or exosome therapy show synergistic effects. Although clinical trials targeting sarcopenia and muscle defects using anti-myostatin antibodies, stem cell-derived products, and acellular scaffolds have reported modest gains in strength and lean mass, no definitive regenerative therapy has been approved. While significant progress has been made, achieving full structural and functional muscle regeneration will require combinatorial approaches that address vascularization, innervation, and the inflammatory microenvironment. Full article

Background: Modified Vaccinia Ankara (MVA) vectors are highly immunogenic vaccine platforms for the delivery of recombinant antigens. Efficient downstream processing is still challenging, particularly because substantial fractions of the virus remain intracellular. While chemical cell lysis that releases MVA particles into the supernatant before clarification can greatly enhance process efficiency and scalability, this step remains insufficiently characterized. Methods: This study assessed the compatibility of ionic, non-ionic, and zwitterionic detergents with the virus as purification target. Polysorbate 20 (Tween 20) was selected as a candidate detergent and evaluated across harvest times of 48–72 h post-infection (hpi) at concentrations of 0.01–0.5% (v/v). Results: The addition of 0.01% to 0.05% Tween 20 at 48 hpi resulted in a twofold increase in supernatant virus within one hour of application. Extended exposure to Tween 20, combined with a 650 mM mixture of NaCl, NaBr, and KCl, promoted virus particle release. However, Tween 20 concentrations above 0.1% reduced MVA infectivity. A filtration cascade using pore sizes of 5 µm and 1.2 µm achieved product yields of 77–83% at 48 hpi and 41–69% at 72 hpi, respectively. Host-cell DNA is an important contaminant during viral vector processing. However, the application of 0.05% (v/v) Tween 20 resulted in a 35% reduction of dsDNA released into the culture supernatant; the nuclei could not be preserved intact under high-salt conditions to avoid the release of cellular DNA. Conclusions: In summary, this comprehensive data demonstrated that non-ionic detergents can be used to induce cell lysis while maintaining infectious activity of enveloped MVA. Full article

Equine infectious anemia virus (EIAV), with the simplest lentiviral genome, is a key model for studying fundamental lentiviral biology. Infectious viral particles are produced only when the Gag protein selectively encapsidates full-length genomic RNA via the packaging signal (Psi), yet the structural and functional features of EIAV Psi remain poorly characterized. Using computational prediction and dimethyl sulfate probing, we identified four stem-loops (SLs) within a ~120 nt region in the 5′ leader of the genome, spanning from downstream of the primer binding site through 20 nt into the gag coding sequence. In vitro dimerization assays demonstrated that a palindromic sequence (5′-CUGGCCAG-3′) within SL3 acts as a critical determinant of RNA dimerization. Functional screening using both an EIAV pseudovirus packaging system and the infectious clone EIAVuk revealed that deletion or mutation of the stem-loops significantly impairs viral packaging and replication, with SL2 deletion or its stem disruption causing the most severe defects. RNA-seq analysis of RNAs bound by wild-type Gag versus a zinc-finger mutant (H391K/H410K) identified two candidate Gag-associated sites: the SL2 stem and the SL2-SL3 junction. Targeting these regions with phosphorothioate-modified antisense oligonucleotides potently inhibited pseudovirus production and the replication of infectious EIAVuk. Our findings defined the secondary structure and functional organization of the EIAV core packaging region and established the SL2 stem and SL2-SL3 junction as candidate packaging determinants and promising targets for RNA-based antiviral intervention. Full article

Background/Objectives: Serial passage in embryonated eggs is widely used to attenuate the infectious bronchitis virus (IBV) for vaccine production; however, the evolutionary processes underlying attenuation and immunogenicity remain incompletely understood. Here, we analyzed genome-wide viral evolution during serial passages to investigate how mutations emerge, persist, are lost, or become fixed over time and how these dynamics relate to changes in pathogenicity and immunogenicity. Methods: Deep sequencing was performed on 11 representative serial passages (P2–P79) of the UY/11/CA/18 strain, including two derivative lineages: P7 VIR (virulent) and P53 VAC (attenuated and immunogenic). Results: This study identified an early adaptive phase characterized by a limited set of mutations potentially associated with genome replication, viral RNA processing, and virion assembly, including a key change in non-structural protein 14 and variants in M and 3c (E). This phase was followed by a broader expansion of the variant spectrum across replicase genes and delayed accumulation of Spike protein variants. Most Spike changes emerged during later passages and exhibited transient dynamics, and only a subset reached a high frequency after the establishment of early replicase- and structural-associated changes. Consistent with these dynamics, P7 VIR diverged before the late accumulation of Spike variants and retained a pathogenic phenotype, whereas P53 VAC diverged after the emergence of early high-frequency variants but before the extensive late-stage Spike variation observed in P79, which was associated with reduced immunogenicity. Conclusions: These findings support a multi-step model of IBV attenuation in which progressive filtering of genome-wide variation shapes distinct evolutionary outcomes during serial passages. This evolutionary framework provides insight into the relationship between attenuation and immunogenicity and may help guide the rational design of live attenuated vaccines. Full article

Bivalve mollusks efficiently bioaccumulate human enteric viruses, posing significant food safety risks. This study assessed the prevalence of Norovirus (NoV GI and NoV GII), Hepatitis A virus (HAV), and Hepatitis E virus (HEV) in 59 samples of live mussels (Mytilus galloprovincialis) collected from the Bulgarian Black Sea coast between July 2022 and July 2023. Viral detection was performed using one-step real-time reverse transcription-polymerase chain reaction (RT-qPCR) following ISO 15216-2 standards, with a mean extraction efficiency of 4.06%. Norovirus GII was the most prevalent pathogen, with detection peaks following intense rainfall events in July 2023. In contrast, all samples tested negative for HAV and HEV. The analysis showed no significant correlation between E. coli contamination levels and the presence of NoV (Mann–Whitney U test, p = 0.565). The viral RNA was detected in several samples that otherwise complied with regulatory bacterial standards for direct consumption (≤230 MPN/100 g). In conclusion, within the limitations of the evaluated sample size and the specific geographically unbalanced sampling design, NoV GII was the predominant genogroup detected. These results suggest that current bacterial indicators may be insufficient to ensure viral safety in these products. In this regard, national control authorities need to undertake timely policies and measures for better and adequate surveillance, control and prevention of viruses in the different parts of the food chain. Full article

Transposable elements (TEs) are increasingly recognized as modulators of innate immunity, yet their antiviral functions remain poorly understood outside mammals and dipterans. Here, we identify a long terminal repeat retrotransposon, LmGypsy, as a key regulator of antiviral defense in Locusta migratoria. The infection of Acrididae reovirus (ARV) induces rapid upregulation of LmGypsy, and its inhibition compromises antiviral resistance. Mechanistically, LmGypsy promotes viral-derived DNA (vDNA) production, which drives Dicer-2-dependent biogenesis of virus-derived small interfering RNAs (vsiRNAs) to enhance RNA interference-mediated viral clearance. Notably, vDNA persists throughout infection, suggesting a role in sustaining antiviral responses. In parallel, LmGypsy activity is positively associated with induction of cyclic GMP-AMP synthase (cGAS)-like receptors (LmcGAS1/2/4) and their downstream effector Stimulator of Interferon Genes (STING). Together, these findings support a dual-layer antiviral strategy and indicate that TE-mediated immunity represents a widespread antiviral mechanism across taxa. Full article

Tomato yellow leaf curl virus (TYLCV) is one of the most destructive viral diseases causing severe yield losses in tomato production worldwide. This study investigated the effects of TYLCV infection on plant growth, photosynthetic physiological responses, and yield formation in greenhouse-grown tomatoes and evaluated the applicability of physiological trait-based yield prediction models. Two large-fruited tomato cultivars widely cultivated in Korean protected horticulture systems, ‘Daphnis’ and ‘Pink Star’, were inoculated with TYLCV under greenhouse conditions, and their growth, physiological responses, and yield characteristics were compared under high- and low-temperature growing seasons. TYLCV infection significantly reduced leaf length, leaf width, and leaf area index (LAI), and decreased both flowering truss number and fruit-setting truss number, resulting in reduced total yield. Physiological analyses showed that infected plants exhibited decreases in the OJIP fluorescence rise curve and Fv/Fm values, indicating a reduced photochemical efficiency in photosystem II. In addition, A–Ci response curve analysis revealed a reduction in net photosynthetic rate, suggesting limited carbon assimilation capacity. Total yield showed significant positive correlations with maximum net photosynthetic rate (Amax), Fv/Fm, and Ci300. GGE and GT biplot analyses further indicated that yield was closely associated with photosynthetic performance and canopy development traits. A multiple regression model based on physiological traits and virus infection status explained a significant proportion of the variation in tomato yield (R² = 0.367), indicating that TYLCV infection acts as a key limiting factor for yield reduction. These findings demonstrate that TYLCV infection restricts tomato productivity through reduced photosynthetic efficiency and altered canopy structure. Moreover, physiological trait-based yield prediction approaches may provide a useful framework for evaluating productivity under viral infection conditions and for developing data-driven crop management strategies in greenhouse tomato production systems. Full article

The innate immune system, particularly the retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) signaling pathway, is a major early defense barrier against influenza A virus infection. However, excessive immune responses can trigger lethal cytokine storms and severe immune-mediated pathology. In this study, we performed a genome-wide CRISPR/dCas9 gene activation screen in human lung epithelial (A549) cells by using an A/Puerto Rico/8/1934 (H1N1) reporter virus, and identified the ubiquitin-specific protease USP17L13 as a novel negative regulator of innate immunity that promotes influenza virus replication. Overexpression of USP17L13 significantly enhanced the replication of multiple subtypes of influenza viruses in A549 cells, including a human pandemic H1N1 virus, seasonal H3N2 viruses, as well as a globally circulating clade, 2.3.4.4b, of the highly pathogenic avian H5N1 virus. Transcriptomic analysis demonstrated that USP17L13 suppresses host antiviral defenses by downregulating nuclear factor kappa B (NF-κB) signaling and arachidonic acid metabolism, while upregulating pathways associated with ribosomal translation and oxidative phosphorylation to facilitate viral production. Mechanistically, USP17L13 attenuates the host interferon (IFN) response by promoting the degradation of the key viral RNA sensors, RIG-I, and melanoma differentiation-associated protein 5 (MDA5). Further analysis revealed that USP17L13 is inducible by type I and type II interferons as well as inflammatory cytokines, suggesting that it may act as a negative-feedback regulator to limit excessive inflammation. Collectively, our findings identify USP17L13 as a previously unrecognized proviral host factor and provide new insight into how host deubiquitinases shape influenza virus-host interactions, with potential implications for host-directed approaches to controlling excessive inflammation during viral infection and improving influenza vaccine production. Full article

Gammaherpesviruses are oncogenic viruses that reprogram host cell metabolism to support viral production. Among these, murine herpesvirus 68 (MHV-68) serves as a model system for studying lytic gammaherpesvirus infection and associated host cell changes. To characterize host transcriptional alterations induced throughout lytic gammaherpesvirus infection and identify novel host pathways that may be therapeutically targeted, we performed temporal bulk RNA-sequencing of mock- and MHV-68-infected NIH 3T3 cells at various timepoints throughout the lytic cycle. Our analysis revealed widespread and progressive host gene expression changes, including robust innate immune pathways and extensive remodeling of metabolic gene expression. We further identified a strong activation of the pentose phosphate pathway (PPP) genes, accompanied by increased abundance in PPP metabolic intermediates. Pharmacological inhibition of the PPP with 6-aminonicotinamide (6-AN) reduced infectious virus production. Moreover, at the intersection of metabolic and transcriptional reprogramming, we identified infection-associated gene expression changes in chromatin-modulating enzymes, including Tet2, and their metabolite co-factors, such as α-KG. Pharmacological inhibition of Ten-Eleven Translocation (TET) enzymatic activity led to a marked decrease in infectious MHV-68 production. Collectively, these findings define a novel metabolic–epigenetic crosstalk that supports productive gammaherpesvirus replication and identifies host pathways that can be targeted to treat lytic gammaherpesvirus infections. Full article

Influenza A virus (IAV) remains a major global health threat despite available vaccines and antiviral agents, while current therapies are limited by drug resistance and safety concerns. Curcuminoids exhibit antiviral and anti-inflammatory activities but are constrained by poor water solubility and low bioavailability. To address these limitations, we investigated the antiviral and immunomodulatory properties of a water-solubilized curcuminoid nanoparticle formulation (C–S/M) in both in vitro and in vivo models of IAV infection. To evaluate the potential antiviral and anti-inflammatory effects of C–S/M, we performed a cytopathic effect (CPE) reduction assay in triplicate at 0.001 MOI and quantitative real-time PCR (qRT-PCR) targeting viral NS1 transcripts in MDCK cells. C–S/M suppressed viral NS1 vRNA levels in MDCK cells at lower curcuminoid-equivalent concentrations than native curcuminoids and attenuated IAV-induced TNF-α, IL-6, and IL-8 production. Furthermore, in vivo antiviral efficacy was evaluated in female C57BL/6 mice intranasally infected with IAV and treated orally with C–S/M. Survival, lung viral loads, pulmonary cytokine levels, and splenic immune cell phenotypes were analyzed. In IAV-infected mice, oral administration of C–S/M modestly improved survival and significantly reduced lung viral burden and pulmonary proinflammatory cytokine levels. In addition, in vivo C–S/M treatment was associated with recovery of virus-suppressed T-cell immune responses, including increased Th1 and activated CD8⁺ T cells, reduced regulatory T-cell expansion, and restoration of multifunctional CD4⁺ and CD8⁺ T cells. These findings suggest that C–S/M exerts antiviral and immunomodulatory effects in experimental IAV infection and may serve as a potential adjunctive candidate for further investigation against influenza-associated inflammation. Full article

Background/Objectives: Recurrent influenza epidemics impose a severe global burden, with conventional vaccines constrained by production time lags and rapid viral mutation. This study aims to explore a novel influenza mRNA vaccine design that balances conserved and mutable antigen regions. By combining hemagglutinin (HA) and neuraminidase (NA) into a dual-target approach, the objective is to simultaneously block viral entry and inhibit progeny release, potentially establishing a proposed “front-blockade, rear-containment” dual protective barrier against multiple H1N1 strains. Methods: We engineered a dual-target tandem mRNA vaccine linking mutated HA with conserved NA, with strategic amino acid mutations introduced into key antigenic sites within the HA head domain. Vaccine efficacy was evaluated in a mouse model. Humoral immunity was assessed by measuring antigen-specific antibody titers, and cellular immunity was evaluated via ELISpot assay. Protective capacity was determined through lethal challenge experiments using diverse H1N1 viral strains. Results: The vaccine successfully expressed the HA-NA tandem antigen at 130 kDa, and the in vitro-expressed antigen exhibited normal neuraminidase activity. Preliminary evidence supported the dual-target concept in model mice: hemagglutination-inhibiting and micro-neutralizing antibodies targeting HA were detected, and serum neuraminidase-inhibiting activity was also observed. In addition to triggering potent cellular immune responses, the vaccine offered total protection against lethal doses of various H1N1 variants. Conclusions: This study suggests a promising dual-target strategy that harmonizes antigen conservation and mutation while potentially establishing a synergistic front-blockade and rear-containment defense. The approach offers a viable pathway for developing improved H1N1 influenza vaccines. Full article

Systemic lupus erythematosus (SLE) is a prototypic systemic autoimmune disorder arising from the convergence of genetic susceptibility, epigenetic remodeling, environmental exposures, and dysregulated immune networks. Although traditionally characterized by autoantibody production and immune complex mediated tissue injury, advances in genomics, systems immunology, and multi-omics profiling have revealed that lupus represents a multilayered failure of immune homeostasis driven by interconnected molecular circuits. Genetic variants enriched in regulatory immune enhancers establish a permissive transcriptional landscape that sensitizes innate nucleic acid sensing pathways and interferon signaling. Epigenetic remodeling further amplifies inflammatory transcriptional programs, while environmental triggers such as ultraviolet radiation and viral infection initiate bursts of nucleic acid release and immune activation. Defective apoptotic cell clearance, mediated in part by scavenger receptor dysfunction and complement abnormalities, increases the availability of immunogenic nucleic acids that engage pattern recognition receptors and drive chronic type I interferon production. This interferon-dominated environment rewires immune cell metabolism, alters differentiation trajectories of T and B lymphocytes, and sustains autoreactive immune circuits. Emerging multi-omics studies reveal distinct molecular endotypes defined by interferon signatures, metabolic states, and immune cell composition, highlighting the heterogeneity of disease mechanisms across patients. In this review, we integrate genetic, epigenetic, metabolic, and immunological insights to propose a systems-level model of lupus pathogenesis in which defective debris clearance, nucleic acid sensing, interferon amplification, and metabolic reprograming form a self-reinforcing pathogenic network. Understanding this integrated molecular architecture provides a foundation for biomarker-guided therapeutic strategies and precision medicine approaches aimed at disrupting the key nodes that sustain chronic autoimmunity in SLE. Full article

The Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) is an important pathogen of the fall armyworm and is used as the basis for biological insecticides. In this study, we examined the relationship between the size–frequency distribution of SfMNPV occlusion bodies (OBs) and their insecticidal characteristics when collected at the end of the replication cycle. Exposure of OBs to 40%, 70%, and 90% (wt/wt) glycerol had no effect on OB pathogenicity. Glycerol density gradient (50–100%) centrifugation was used to separate OBs into two fractions. OBs recovered from the upper fraction of the gradient had a significantly smaller median cross-sectional area than those harvested from the lower fraction. These fractions also differed significantly in their size–frequency distributions. The OB concentration–mortality response of S. frugiperda second instars did not differ significantly between the two fractions or with non-centrifuged OBs. The median survival time was similar for insects inoculated with OBs from the upper and lower fractions but was significantly shorter in insects inoculated with non-centrifuged OBs. The proportion of mature OBs (67–71%) and the number of viral genome copies (1.33–1.40 × 10⁸ copies/µL) did not differ significantly between the upper and lower OB fractions. These findings suggest that altering the size–frequency distribution by density gradient centrifugation is not a useful technique for selecting large OBs with high insecticidal activity as part of the baculovirus insecticide production process. Future studies should evaluate a range of OB size separation techniques to determine their effects on OB insecticidal characteristics. Full article

The Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) has evolved sophisticated immune-evasion strategies to establish a productive infection in the host, primarily by counteracting the innate antiviral response. Here, we demonstrate for the first time that the PRRSV non-structural protein NSP8 suppresses NF-κB-dependent antiviral signalling by hijacking the host ubiquitin-conjugating enzyme UBE2K and inducing the degradation of IKKα, a pivotal kinase in the NF-κB pathway. PRRSV infection led to significant upregulation of host UBE2K, which in turn facilitated viral replication. Mechanistically, we found that NSP8 interacts directly with IKKα, triggering its degradation by the proteasome. Furthermore, we revealed that this process was facilitated by the host protein UBE2K, which acted as a crucial cofactor by directly interacting with NSP8 and thereby enhancing its activity against IKKα. This disruption blocked the activation of the NF-κB pathway and suppressed the expression of downstream antiviral factors, such as TNF-α, IL-6 and IFN-β, ultimately facilitating PRRSV replication. All of these findings showed that NSP8 is an important part of the process by which the host NF-κB pathway is blocked by viruses. This is a new way in which PRRSV avoids the immune system. Full article

African swine fever virus (ASFV) is the causative agent of African swine fever (ASF), a fatal and highly contagious disease, resulting in enormous losses to the global swine industry. No licensed vaccines or effective therapeutics are currently available to control ASFV infection. Interferons (IFNs) serve as key mediators of host antiviral immunity by inducing interferon-stimulated genes (ISGs), but the specific mechanisms by which individual ISGs restrict ASFV replication remain unclear. Interferon-induced protein with tetratricopeptide repeats 3 (IFIT3, also called ISG60) has been shown to exhibit antiviral activity against various viruses, but its role in ASFV infection has not been previously studied. Here, we used porcine alveolar macrophages (PAMs), the primary target cells of ASFV, to investigate IFIT3’s function in ASFV replication. We found that overexpression of IFIT3 inhibited ASFV replication, while its knockdown enhanced viral propagation. Mechanistically, IFIT3 directly blocked ASFV adsorption to host cells, thereby suppressing all subsequent stages of the viral cycle. IFIT3 also specifically interacted with ASFV F334L, an early viral gene product that encodes the small subunit of ribonucleotide reductase, a key enzyme for viral DNA synthesis. Additionally, IFIT3 positively regulated the STAT1/TBK1/IRF3 signaling axis: its overexpression increased phosphorylation of TBK1 and IRF3, as well as the protein level of STAT1, while IFIT3 knockdown attenuated activation of these molecules. Transcriptomic analysis of IFIT3-knockout PAMs revealed significant suppression of innate immune pathways, including type I interferon, JAK-STAT, and RIG-I-like receptor pathways, along with downregulated expression of core antiviral molecules such as ISG15, MX1, and STAT1. Conversely, pathways related to viral adsorption, endocytosis, and cytoskeleton were activated, and pathways involved in protein translation initiation, endoplasmic reticulum stress, and autophagy were dysregulated, creating a favorable intracellular environment for ASFV replication. In conclusion, IFIT3 restricts ASFV replication possibly by inhibiting viral adsorption and promoting innate immune signaling, identifying it as a potential therapeutic target against ASFV. This study’s limitation is its in vitro PAM model; future work will validate IFIT3’s role in vivo and develop targeted inhibitors. Full article