Infectious laryngotracheitis virus (ILTV) exhibits a cascade expression pattern of encoded genes, and ICP4 is the only immediate-early gene of ILTV, which plays a crucial role in initiating the subsequent viral genes. Therefore, studying the transcriptional regulation mechanism of ICP4 holds promise for effectively blocking ILTV infection and spread. Host transcriptional factors p53 and Fos are proven to regulate a variety of viral infections, and our previous studies have demonstrated their synergistic effects in regulating ILTV infection. In this study, we constructed eukaryotic expression vectors for p53 and Fos as well as their specific siRNAs and transfected them into a chicken hepatoma cell line. The results showed that knocking down p53 or Fos significantly inhibited ICP4 transcription, while overexpressing p53 or Fos had an opposite effect. A further CoIP and ChIP-qPCR assay suggested p53 and Fos physically interacted with each other, and jointly bound to the upstream transcriptional regulatory region of ICP4. To elucidate the specific mechanisms of p53 and Fos in regulating ICP4 transcription, we designed p53 and Fos protein mutants by mutating their DNA binding domains, which significantly reduced their binding ability to DNA without affecting their interaction. The results showed that Fos directly bound to the promoter region of ICP4 as a binding target of p53, and the p53–Fos protein complex acted as a transcriptional co-regulator of ICP4. Studying the transcriptional process and regulatory pattern of ICP4 is of great significance for understanding the molecular mechanism of ILTV infection, and thus for finding effective methods to control and prevent it.

Background/Objectives: Despite decades of extensive vaccinations against avian infectious bronchitis virus (IBV) infection, outbreaks caused by constantly emerging variants due to genome recombination between different viral strains, including vaccine strains, occur annually worldwide. The development of novel vaccines with favorable safety and effectiveness is required but is hindered by a limited understanding of vaccination against IBV. Methods: Here, we performed a comprehensive analysis of the in vivo dynamics of peripheral blood mononuclear cells (PBMCs) in specific pathogen-free chickens inoculated with the widely used live attenuated IBV vaccine strain H120 at single-cell level, using high-throughput single-cell transcriptome sequencing (scRNA-seq). Results: High-quality sequencing dataset for four scRNA-seq data containing the transcriptomes of 29,846 individual chicken PBMCs were obtained, defining 22 populations and 7 cell types based on distinct molecular signatures and known markers. Further integrative analysis constructed the time series dynamic cell transition and immune response landscapes within the two weeks post-prime vaccination against IBV. Enhanced crosstalk between antigen-presenting cells and T lymphocytes was revealed as early as four days post-vaccination. The specific immune cell populations and their comprehensive cellular and molecular networks involved in the initiation phase of antiviral adaptive immune responses were elucidated in details. Conclusions: Our study provides a comprehensive view of the dynamic initiation of immune responses in chickens against IBV infection at the cellular and molecular levels, which provides theoretical support and potential solutions for the future rational design of safe and effective vaccines, the augmentation of the efficacy of current vaccines, and the optimization of immune programs.

Viral oncolysis is considered a promising cancer treatment method because of its good tolerability and durable anti-tumor effects. Compared with other oncolytic viruses, Newcastle disease virus (NDV) has some distinct advantages. As an RNA virus, NDV does not recombine with the host genome, making it safer compared with DNA viruses and retroviruses; NDV can induce syncytium formation, allowing the virus to spread among cells without exposure to host neutralizing antibodies; and its genome adheres to the hexamer genetic code rule (genome length as a multiple of six nucleotides), ensuring accurate replication, low recombination rates, and high genetic stability. Although wild-type NDV has a killing effect on various tumor cells, its oncolytic effect and working mechanism are diverse, increasing the complexity of generating engineered oncolytic viruses with NDV. This study aims to employ whole-genome CRISPR-Cas9 knockout screening and RNA sequencing to identify putative key regulatory factors involved in the interaction between NDV and human colon cancer HCT116 cells and map their global interaction networks. The results suggests that NDV infection disrupts cellular homeostasis, thereby exerting oncolytic effects by inhibiting cell metabolism and proliferation. Meanwhile, the antiviral immune response triggered by NDV infection, along with the activation of anti-apoptotic signaling pathways, may be responsible for the limited oncolytic efficacy of NDV against HCT116 cells. These findings not only enhance our understanding of the oncolytic mechanism of NDV against colonic carcinoma but also provide potential strategies and targets for the development of NDV-based engineered oncolytic viruses.

Newcastle disease virus (NDV) is a promising oncolytic virus, but tumor heterogeneity constrains its clinical translation. The key determinants driving variable NDV oncolytic potency amid tumor heterogeneity remain incompletely elucidated. The main scope of this study included analyzing 22 human cancer cell lines representing 11 tumor types and identifying five gene co-expression modules associated with NDV susceptibility through weighted gene co-expression network analysis. Integrative multi-omics analyses of NDV-infected HCT116 cells, the least-susceptible cell line in our panel, predicted metabolic processes, innate immune defenses, and multiple forms of cell death as candidate pathways modulating NDV oncolytic efficacy. These key bioinformatic findings were further validated by genome-wide CRISPR-Cas9 screening, which uncovered POLR2G and SREBF1 as central components of the pro-oncolytic network and TNFRSF1A, TNFAIP3, and CASP9 as core mediators of the anti-oncolytic network. Their functional roles were further verified via genetic manipulation and pharmacological perturbation of JAK-STAT, TLR4, and apoptotic signaling. In conclusion, our findings support a bidirectional model wherein host metabolic programs promote NDV replication and oncolysis, whereas antiviral-innate immune signaling restricts them, providing candidate targets for host-directed combination therapy amid tumor heterogeneity.

Infectious laryngotracheitis virus (ILTV), formally known as Gallid alphaherpesvirus 1, represents a prominent alphaherpesvirus that poses a significant threat to the global poultry industry. Current routine vaccination strategies fail to eliminate latent infection. Host–pathogen interaction networks have become a key focus in antiviral research. Our previous study demonstrated that activation of the MEK/ERK signaling pathway upon ILTV infection restricts host cellular metabolic activity to mount protective host antiviral responses, yet the underlying molecular mechanism remains unclear. The present work systematically dissects the contribution of MEK/ERK signaling to intrinsic host defense against ILTV. The results show that ILTV infection activates the MEK/ERK pathway, which in turn promotes the expression, activation, and nuclear translocation of the transcription factor Fos. As a core transcriptional regulator, Fos represses host metabolic gene expression, thereby restricting viral replication and proliferation. Integrated multi-omics analyses further demonstrate that the MEK/ERK-Fos-metabolic regulatory axis operates uniformly during infection with avian, human, and porcine alphaherpesviruses, suggesting a broadly conserved host antiviral mechanism. This consistent cross species signaling pattern points toward an evolutionarily conserved host antiviral strategy and provides potential molecular targets for the development of broad-spectrum antiviral strategies against alphaherpesviruses.