Exosomal miRNAs from individual cells are crucial in regulating the immune response to infectious diseases. In this study, we performed small RNA sequencing (small RNA-seq) analysis to identify the expressed and associated exosomal miRNAs in the serum of cattle infected with lumpy skin disease virus (LSDV). Cattle were infected with a 10^6.5 TCID50/mL LSDV Vietnam/HaTinh/CX01 (HT10) strain and exosomal miRNA expression in the serum of infected cattle was analyzed using small RNA sequencing (small RNA-seq). We identified 59 differentially expressed (DE) miRNAs in LSDV-infected cattle compared to uninfected controls, including 18 upregulated and 41 downregulated miRNAs. These 59 miRNAs were used to predict 7656 target genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the target genes were enriched in several biological processes and pathways associated with viral replication, immune response, virus–host interactions, and signal transduction. Additionally, we identified 708 potentially novel cattle miRNAs corresponding to 710 genomic loci. The transcription levels of five miRNA genes (bta-miR-11985, bta-miR-1281, bta-miR-12034, bta-miR-let-7i, and bta-miR-17-5p) were validated using reverse transcription quantitative real-time PCR, showing consistency with the small RNA-seq results. Overall, these findings provide significant insights into the immune and protective responses during LSDV infection in cattle, offering valuable information on identifying new biomarkers and understanding the pathogenesis of LSDV.

Avian influenza viruses (AIVs) pose a significant threat to global poultry production, necessitating effective control strategies to mitigate economic losses and ensure animal welfare. Long non-coding RNAs (lncRNAs) have emerged as crucial regulators of immune responses, yet their roles in AIV-infected chickens remain poorly understood. This study aimed to investigate the expression profiles of lncRNAs and their targets in Vietnamese Ri chickens infected with the highly pathogenic AIV (HPAIV) H5N1. Through RNA sequencing, we identified novel lncRNAs and analyzed differentially expressed (DE) transcripts at 1 and 3 days post-infection (dpi) in chicken lung tissue. Our results revealed a higher number of DE lncRNAs and mRNAs at 1 dpi and 3 dpi, respectively, compared to control, with resistant chickens exhibiting a notably stronger immune response than susceptible chickens at 3 dpi. Functional analysis implicated these lncRNAs in immune-related pathways crucial for host responses to H5N1 viral infection. Furthermore, we identified lncRNA-mRNA interactions associated with antiviral responses and immune function. Notably, several genes involved in antiviral resistance and immune responses showed higher expression in resistant chickens, confirming their stronger antiviral response. Overall, our study provides insights into the role of lncRNAs in the host's response to HPAIV H5N1 infection in chickens and highlights potential candidates for further investigation into host-pathogen interactions. These findings could drive the development of novel control strategies for AIVs, significantly enhancing poultry health and biosecurity.

Exosomes are emerging as key mediators of host-pathogen interactions, particularly as carriers of viral components during infection. This study aims to examine the immunomodulatory effects of serum-derived exosomes from Brown Leghorn chickens infected with low pathogenic avian influenza virus (LPAIV) or highly pathogenic avian influenza virus (HPAIV). These exosomes (CTRL-EXO [noninfected], LPAIV-EXO, and HPAIV-EXO) were intramuscularly injected into naïve chickens, after which tissues and serum were collected. Cytokine gene expression in immune-related tissues (lung, spleen, and trachea) was quantified through reverse transcription-quantitative polymerase chain reaction to evaluate the immune response. Unlike the lung and trachea, the spleen showed the strongest immune response following exosome injection, associated with elevated antiviral cytokines and interferons in the AIV-exosome group. In parallel, these exosomes were applied to chicken macrophage HD11 cells to determine cellular uptake and cytokine expression using reverse transcription-quantitative polymerase chain reaction. Furthermore, immunocytochemistry was performed to detect exosome-delivered viral nucleoprotein and nonstructural protein 1 proteins in HD11 cells. LPAIV-EXO induced the strongest immune activation, evidenced by increased cytokine expression and immunochemical detection of viral proteins. Collectively, these findings indicate that AIV-derived exosomes modulate host immune responses in vivo and in vitro, underscoring their potential in immune regulation and vaccine development.