Search Results (1,908)

Background/Objectives: Non-coding microRNA-34a (miR-34a) regulates the expression of key factors involved in several cellular processes, such as differentiation, apoptosis, proliferation, cell cycle, and senescence. Deregulation of the expression of these factors is implicated in the onset and progression of several human diseases, including cancer, neurodegenerative disorders, and pathologies associated with viral infections and inflammation. Despite numerous studies, the molecular mechanisms regulated by miR-34a remain to be fully understood. The present study aimed to generate miR-34a knockout cell lines to identify novel genes potentially regulated by its expression. Methods: We employed the CRISPR-Cas9 gene editing system to knock out the hsa-miR-34a gene in HeLa and 293T cell lines, two widely used models for studying molecular and cellular mechanisms. We compared proliferation rates and gene expression profiles via RNA-seq and qPCR analyses between the wild-type and miR-34a KO cell lines. Results: Knockout of miR-34a resulted in a decreased proliferation rate in both cell lines. Noteworthy, the ablation of miR-34a resulted in increased expression of the long non-coding RNA MALAT1. Additionally, miR-34a-5p silencing in the A375 melanoma cell line led to MALAT1 overexpression. Conclusions: Our findings support the role of the miR-34a/MALAT1 axis in regulating proliferation processes. Full article

Human leukocyte antigen class I (HLA-I) molecules present intracellular peptides on the cell surface to enable CD8+ T cells to effectively control viral infections. Many viruses disrupt this antigen presentation pathway to evade immune detection. In this study, we demonstrate that SARS-CoV-2 Nsp1 impairs both the constitutive and interferon-γ (IFN-γ)-induced upregulation of HLA-I. Moreover, Nsp1 also blocks IFN-γ-induced expression of HLA-II. We found that, contrary to previously published work, the early SARS-CoV-2 B 1.1.7 Alpha variant lacking the accessory protein ORF8 retained full capacity to downregulate HLA-I, comparable to an ORF8-expressing wild-type isolate. While ectopic overexpression of ORF8 could reduce HLA-I surface levels, this effect was only observed at high expression levels. In contrast, moderate expression of the viral protein Nsp1 was sufficient to potently suppress both basal and IFN-γ-induced HLA-I, as well as HLA-II expression. To probe the underlying mechanism, we analyzed HLA-I-associated genes in previously published RNA-sequencing datasets and confirmed that Nsp1 reduces expression of components required for HLA-I biosynthesis and antigen processing. These findings identify Nsp1 as a key factor that impairs antigen presentation pathways, potentially contributing to the ability of SARS-CoV-2 to modulate immune recognition. Full article

Background: Influenza viruses are major pathogens responsible for respiratory infections and pose significant risks to densely populated urban areas. RT-qPCR has made substantial contributions in controlling virus transmission during previous COVID-19 epidemics, but it faces challenges in terms of detection time for large sample sizes and susceptibility to nucleic acid contamination. Methods: Our study designed loop-mediated isothermal amplification primers for three common influenza viruses: A/H3N2, A/H1N1, and B/Victoria, and utilized a 4-channel microfluidic chip to achieve simultaneous detection. The chip initiates amplification by centrifugation and allows testing of up to eight samples at a time. Results: By creating a closed amplification system in the microfluidic chip, aerosol-induced nucleic acid contamination can be prevented through physically isolating the reaction from the operating environment. The chip can specifically detect A/H1N1, A/H3N2, and B/Victoria and has no signal for other common respiratory viruses. The testing process can be completed within 1 h and can be sensitive to viral RNA at concentrations as low as 10⁻³ ng/μL for A/H1N1 and A/H3N2 and 10⁻¹ ng/μL for B/Victori. A total of 296 virus swab samples were further analyzed using the microfluidic chip method and compared with the classical qPCR method, which resulted in high consistency. Conclusions: Our chip enables faster detection of influenza virus and avoids nucleic acid contamination, which is beneficial for POCT establishment and has lower requirements for the operating environment. Full article

The development of severe SARS-CoV-2 pneumonia is characterized by extensive lung inflammation, which, in turn, leads to respiratory distress and a decline in blood oxygen levels. Hospital admission, along with intensive care or ventilator usage, becomes necessary because this condition leads to serious respiratory problems. This review aims to provide a comprehensive overview of the pathophysiological mechanisms, diagnostic methods, and current therapeutic options for pneumonia caused by the SARS-CoV-2 virus. The pathophysiological process of severe pneumonia due to SARS-CoV-2 infection is characterized by direct lung damage from viral replication, an excessive immune system response, inflammation, impaired gas exchange, and multi-organ failure. The coexistence of various medical conditions leads to substantial lung impairment, resulting in hypoxia and respiratory failure, which can ultimately lead to fatal outcomes. The diagnosis of severe SARS-CoV-2 pneumonia is made through a combination of clinical, radiologic, and laboratory findings. A multifaceted approach integrating antiviral therapy, corticosteroids, oxygen supplementation, ventilatory management, and immunomodulation is imperative to control inflammation and enhance clinical outcomes. Early intervention, meticulous monitoring, and personalized care are paramount for enhancing survival and mitigating complications in critically ill patients with COVID-19 pneumonia. Full article

Marek’s disease (MD), induced by the highly contagious Marek’s disease virus (MDV), remains a significant challenge to global poultry health despite extensive vaccination efforts. This study employed integrated transcriptomic and metabolomic analyses to investigate liver responses in naturally MDV-infected Wenchang chickens during late infection stages. RNA sequencing identified 959 differentially expressed genes (DEGs) between the infected and uninfected groups. Functional enrichment analysis demonstrated that these DEGs were primarily associated with canonical pathways related to metabolism and cellular processes, including lipid, carbohydrate, and amino acid metabolism, as well as the p53 signaling pathway, cell cycle, and apoptosis. Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) detected 561 differentially expressed metabolites (DEMs), showing near-significant enrichment (p = 0.069) in phenylalanine metabolism. Integrated analysis of transcriptomics and metabolomics data highlighted that critical gene–metabolite pairs such as SGPL1-palmitaldehyde–sphinganine-1-phosphate and ME1-NADP+–malic acid potentially mediate functional crosstalk between sphingolipid metabolism and cellular redox homeostasis during viral oncogenesis. This comprehensive mapping of regulatory networks provides insights into host–virus interactions during MDV pathogenesis, offering potential applications in immunomodulation approaches, targeted therapeutic strategies, and vaccine adjuvant development. Full article

Viruses use a range of sophisticated strategies to evade detection by cytotoxic T-lymphocytes (CTLs) within host cells. Beyond elaborating dedicated viral proteins that disrupt the MHC class I antigen-presentation machinery, some viruses possess intrinsic, cis-acting genome-encoded elements that interfere with antigen processing and display. These protein features, including G-quadruplex motifs, repetitive peptide sequences, and rare-codon usage, counterintuitively limit production of proteins critical to virus survival, particularly during latency. By slowing viral protein synthesis, these features reduce antigen production and proteosomal degradation, ultimately limiting the generation of peptides for MHC I presentation. These built-in evasion tactics enable viruses to remain “invisible” to CTLs during latency. While these primary sequence intrinsic immune evasion (PSI) mechanisms are well-described in select herpesviruses, emerging evidence suggests that they may also play a critical role in RNA viruses. How these proteins are made, rather than what they functionally target, determines their immune evasion properties. Understanding PSI mechanisms could rationally inform the design of engineered viral antigens with altered or removed evasion elements to restore antigen CTL priming and activation. Such vaccine strategies have the potential to enhance immune recognition, improve clearance of chronically infected cells, and contribute to the treatment of persistent viral infections and virus-associated cancers. Full article

Background: Sudden-onset bilateral mixed hearing loss in adults is an extremely rare condition but challenging to diagnose and treat. Conductive hearing loss is associated with otitis media, while the simultaneous presence of a sensorineural component requires supplementary investigation for possible shared pathophysiological mechanisms. Case Presentation: We report the case of a 41-year-old male who was admitted to our hospital with a 48 h history of bilateral, fast progressive hearing loss following a viral illness. The audiologic testing revealed bilateral severe mixed hearing loss. Tympanometry indicated the presence of middle-ear effusion, and myringotomy confirmed the existence of pressurized serous fluid. Treatment consisted of systemic and intratympanic corticosteroids, antibiotics, and supportive therapy. The patient had an unexpected full recovery of auditory function within one month. Discussion: Multiple hypotheses were considered. We hypothesized the coexistence of unrelated conductive and sensorineural hearing loss or a unifying pathological process. Theories discussed include a direct viral insult to the cochlear structures or even pressure-mediated damage to the basal cochlea due to the simultaneous inward displacement of the oval and round windows. The complete resolution of hearing loss is the indicator of a reversible etiology, possibly due to transient inner ear dysfunction secondary to middle-ear pathology or viral infection. Conclusions: This case illustrates the complexity of diagnosing acute mixed hearing loss. This report emphasizes a rare case of sudden-onset bilateral mixed hearing loss with a complete recovery, contributing valuable insight into under-reported and diagnostically complex presentations. Full article

As a pivotal model organism in Lepidoptera research, the silkworm (Bombyx mori) holds significant importance in life science due to its economic value and biotechnological applications. Advancements in proteomics and bioinformatics have enabled substantial progress in characterizing the B. mori proteome. Systematic screening and identification of protein–protein interactions (PPIs) have progressively elucidated the molecular mechanisms governing key biological processes, including viral infection, immune regulation, and growth development. This review comprehensively summarizes traditional PPI detection techniques, such as yeast two-hybrid (Y2H) and immunoprecipitation (IP), alongside emerging methodologies such as mass spectrometry-based interactomics and artificial intelligence (AI)-driven PPI prediction. We critically analyze the strengths, limitations, and technological integration strategies for each approach, highlighting current field challenges. Furthermore, we elaborate on the molecular regulatory networks of Bombyx mori nucleopolyhedrovirus (BmNPV) from multiple perspectives: apoptosis and cell cycle regulation; viral protein invasion and trafficking; non-coding RNA-mediated modulation; metabolic reprogramming; and host immune evasion. These insights reveal the dynamic interplay between viral replication and host defense mechanisms. Collectively, this synthesis aims to provide a robust theoretical foundation and technical guidance for silkworm genetic improvement, infectious disease management, and the advancement of related biotechnological applications. Full article

Ebola virus (EBOV) causes severe hemorrhagic fevers in humans, and effective countermeasures remain limited. The EBOV-encoded major matrix protein VP40 is essential for viral assembly, budding, and particle release, making it a promising target for antiviral drug development. However, no approved drugs currently target the viral particle formation process. In this study, we established a simple and highly sensitive screening system to evaluate VP40-mediated virus-like particle (VLP) formation under biosafety level −2 conditions. The system uses the HiBiT luminescence-based reporter fused to VP40, allowing for the detection of VP40 release. Our results demonstrate that the HiBiT sequence fused at the N-terminus [HiBiT-VP40 (N)] retains VP40′s ability to form VLPs, supporting its use as a functional reporter. Furthermore, we validated the system by assessing the role of Rab11-dependent trafficking in VP40-mediated budding and by evaluating the effect of nocodazole, a microtubule depolymerizer, on VLP release. This novel screening system provides a convenient and reliable platform for screening potential inhibitors targeting the late stages of EBOV infection, including viral particle formation and release. Additionally, its potential adaptability to other filoviruses suggests wide applicability in the discovery and development of additional novel therapeutic agents. Full article

Persistent high-risk human papillomavirus (HR-HPV) infection is closely associated with the development of cervical intraepithelial neoplasia (CIN) and cervical cancer. In recent years, the potential impact of viral co-infections on this process has also been investigated. This study investigated the presence of HR-HPV, HSV-1/2, and HHV-8 DNA in formalin-fixed paraffin-embedded (FFPE) cervical biopsy samples, as well as their association with lesion severity. A total of 276 FFPE cervical tissue samples were evaluated. Viral DNA was detected by real-time PCR. The samples were histopathologically classified as normal/non-dysplastic, low-grade (LSIL), and high-grade (HSIL) lesions. HR-HPV DNA was detected in 112 samples (40.6%), with the highest prevalence observed in the 30–39 age group (51.2%). Among the HPV-positive cases, 46.5% (52/112) had single-type infections, 32.1% (36/112) had multiple-type infections, and 21.4% (24/112) were untypable. Together, these categories accounted for all HPV-positive samples. The most common genotype was HPV-16 (16.7%). HHV-8 and HSV-2 DNA were not detected. HSV-1 DNA was detected in only three non-dysplastic, HPV-negative cervical samples. In conclusion, HR-HPV DNA was detected in 40.6% of cervical biopsy samples and showed a significant association with increasing histological severity, highlighting its critical role in the progression of cervical lesions. Although the absence of HHV-8 and HSV-2 suggests a limited contribution of these viruses to cervical disease, the use of a single real-time PCR assay limits the ability to draw generalized conclusions regarding their clinical relevance. Further large-scale, multicenter studies employing both tissue-based and serological approaches are needed to validate these findings and to better understand the dynamics of viral co-infections in cervical disease. Full article

Herpesviruses are DNA viruses that evade the immune response and persist as lifelong infections. Human gamma-herpesviruses Epstein–Barr virus (EBV) and Kaposi’s sarcoma herpesvirus (KSHV) are oncogenic; they can lead to cancer. Oncogenic viruses are responsible for 10–15% of human cancer development, which can have poor prognoses. Non-coding RNAs (ncRNAs) are RNAs that regulate gene expression without encoding proteins, and are being studied for their roles in viral immune evasion, infection, and oncogenesis. ncRNAs are classified by their size, and include long non-coding RNAs, microRNAs, and circular RNAs. EBV and KSHV manipulate host ncRNAs, and encode their own ncRNAs, regulating host processes and immune responses. Viral ncRNAs regulate host functions by post-transcriptionally modifying host RNAs, and by serving as mimics of other host RNAs, promoting immune evasion. ncRNAs in gamma-herpesvirus infection are also important for tumorigenesis, as dampening immune responses via ncRNAs can upregulate pro-tumorigenic pathways. Emerging topics such as RNA modifications, target-directed miRNA degradation, competing endogenous RNA networks, and lncRNA/circRNA–miRNA interactions provide new insights into ncRNA functions. This review compares ncRNAs and the mechanisms of viral immune evasion in EBV and KSHV, while also expanding on recent developments in the roles of ncRNAs in immune evasion, viral infection, and oncogenesis. Full article

Respiratory viral infections are a leading cause of early childhood hospitalizations in the United States. Neonatal immune responses are reliant on innate mechanisms during the first few months of life. Interferons (IFNs) are a key component of this response. These antiviral cytokines are produced early in infection and aid in viral control and clearance. Although generally considered protective in the setting of respiratory viral infections, the recent literature has suggested that IFNs may exacerbate disease. In the process of promoting an antiviral environment, IFNs impede cell proliferation, contribute to pulmonary barrier disruption, and generate reactive oxygen species. This is not tolerated in the rapidly developing neonatal lung. Therefore, IFNs contribute to pathogenesis in the influenza-infected neonate. This review focuses on the potential mechanisms that drive IFN-induced toxicity in neonates and prospective therapeutics to mitigate this toxicity. Full article

Chikungunya virus (CHIKV), a mosquito-borne alphavirus, has re-emerged, causing widespread outbreaks and a significant clinical burden. Despite advances in virology, the molecular mechanisms governing CHIKV’s interaction with host cells remain poorly understood. In this study, we aimed to identify novel host protein interactors of the CHIKV nonstructural protein 3 (nsP3), a critical component of the viral replication complex, using mass spectrometry-based proteomic profiling in liver-derived Huh7 cells. Co-immunoprecipitation followed by LC-MS/MS identified a wide array of host proteins associated with nsP3, revealing 52 proteins classified as high-confidence (FDR of 1%, and unique peptides > 2) CHIKV-specific interactors. A bioinformatic analysis using STRING and Cytoscape uncovered interaction networks enriched in metabolic processes, RNA processing, translation regulation, cellular detoxification, stress responses, and immune signaling pathways. A subcellular localization analysis showed that many interactors reside in the cytosol, while others localize to the nucleus, nucleolus, and mitochondria. Selected novel host protein interactions were validated through co-immunoprecipitation and immunofluorescence assays. Our findings provide new insights into the host cellular pathways hijacked by CHIKV and highlight potential targets for therapeutic intervention. This is the first report mapping direct nsP3–host protein interactions in Huh7 cells during CHIKV infection. Full article

Background: Modern viral vector production needs to consider process intensification for higher yields from smaller production volumes. However, innate antiviral immunity triggered in the producer cell may limit virus replication. While commonly used cell lines (e.g., Vero or E1A-immortalised cells) are already compromised in antiviral pathways, the redundancy of innate signaling complicates host cell optimization by genetic engineering. Small molecules that are hypothesized to target antiviral pathways (Viral Sensitizers, VSEs) added to the culture media offer a versatile alternative to genetic modifications to increase permissiveness and, thus, viral yields across multiple cell lines. Methods: To explore how the yield for a chimeric Zika vaccine candidate (YF-ZIK) could be further be increased in an intensified bioprocess, we used spin tubes or an Ambr15 high-throughput microbioreactor system as scale-down models to optimize the dosing for eight VSEs in three host cell lines (AGE1.CR.pIX, BHK-21, and HEK293-F) based on their tolerability. Results: Addition of VSEs to an already optimized infection process significantly increased infectious titers by up to sevenfold for all three cell lines tested. The development of multi-component VSE formulations using a design of experiments approach allowed further synergistic titer increases in AGE1.CR.pIX cells. Scale-up to 1 L stirred-tank bioreactors and 3D-printed mimics of 200 or 2000 L reactors resulted in up to threefold and eightfold increases, respectively. Conclusions: Addition of single VSEs or combinations thereof allowed a further increase in YF-ZIK titers beyond the yield of an already optimized, highly intensified process. The described approach validates the use of VSEs and can be instructive for optimizing other virus production processes. Full article

Sleep deprivation impairs immune function, and melatonin has emerged as a key mediator in this process. This narrative review analyzes 50 studies published between 2000 and 2025 to determine the extent to which reduced melatonin synthesis contributes to immune dysregulation. Consistent sleep loss lowers melatonin levels, which correlates with elevated proinflammatory cytokines (e.g., IL-6 and TNF-α), increased oxidative stress, and reduced immune cell activity, including that of natural killer (NK) cells and CD4+ lymphocytes. Melatonin regulates immune pathways, including NF-κB signaling. It also supports mitochondrial health and helps maintain gut barrier integrity. These effects are particularly relevant in vulnerable populations, including older adults and shift workers. Experimental findings also highlight melatonin’s therapeutic potential in infections like SARS-CoV-2, where it modulates inflammatory responses and viral entry mechanisms. Despite the heterogeneity of study methodologies, a consistent correlation emerges between circadian disruption, melatonin suppression, and immune imbalance. These findings underscore melatonin’s dual role as a chronobiotic and immunomodulator. Addressing sleep loss and considering melatonin-based interventions may help restore immune homeostasis. More clinical trials are needed to determine the best dosing, long-term efficacy, and population-specific strategies for supplementation. Promoting healthy sleep is crucial for preventing chronic inflammation and diseases associated with immune dysfunction. Full article