Integrated host and viral transcriptome analyses reveal pathology and inflammatory response mechanisms to ALV-J injection in SPF chickens

Avian leukosis virus (ALV) is detrimental to poultry health and causes substantial economic losses from mortality and decreased performance. Because tumorigenesis is a complex mechanism, the regulatory architecture of the immune system is likely to include the added dimensions of modulation by miRNAs and long-noncoding RNA (lncRNA). To characterize the response to ALV challenge, we developed a novel methodology that combines four datasets: mRNA expression and the associated regulatory factors of miRNA and lncRNA, and ALV gene expression. Specific Pathogen-Free (SPF) layer chickens were infected with ALV-J or maintained as non-injected controls. Spleen samples were collected at 40 days post injection (dpi), and sequenced. There were 864 genes, 7 miRNAs and 17 lncRNAs differentially expressed between infected and non-infected birds. The combined analysis of the 4 RNA expression datasets revealed that ALV infection is detected by pattern-recognition receptors (TLR9 and TLR3) leading to a type-I IFN mediated innate immune response that is modulated by IRF7 and IRF1. Co-expression network analysis of mRNA with miRNA, lncRNA and virus genes identified key elements within the complex networks utilized during ALV response. The integration of information from the host transcriptomic, epigenetic and virus response also has the potential to provide deeper insights into other host-pathogen interactions.