The Relationship Between the Alternative exon 7 Splice Variant of theBFGene and MHC-Related Marek's Disease Resistance in Chickens

Exploration of Alternative Splicing (AS) Events in MDV-Infected Chicken Spleens

Marek’s disease (MD) was an immunosuppression disease induced by Marek’s disease virus (MDV). MD caused huge economic loss to the global poultry industry, but it also provided an ideal model for studying diseases induced by the oncogenic virus. Alternative splicing (AS) simultaneously produced different isoform transcripts, which are involved in various diseases and individual development. To investigate AS events in MD, RNA-Seq was performed in tumorous spleens (TS), spleens from the survivors (SS) without any lesion after MDV infection, and non-infected chicken spleens (NS). In this study, 32,703 and 25,217 AS events were identified in TS and SS groups with NS group as the control group, and 1198, 1204, and 348 differently expressed (DE) AS events (p-value < 0.05 and FDR < 0.05) were identified in TS vs. NS, TS vs. SS, SS vs. NS, respectively. Additionally, Function enrichment analysis showed that ubiquitin-mediated proteolysis, p53 signaling pathway, and phosphatidylinositol signaling system were significantly enriched (p-value < 0.05). Small structural variations including SNP and indel were analyzed based on RNA-Seq data, and it showed that the TS group possessed more variants on the splice site region than those in SS and NS groups, which might cause more AS events in the TS group. Combined with previous circRNA data, we found that 287 genes could produce both circular and linear RNAs, which suggested these genes were more active in MD lymphoma transformation. This study has expanded the understanding of the MDV infection process and provided new insights for further analysis of resistance/susceptibility mechanisms.

Interleukin-dependent modulation of the expression of MHC class I and MHC class II genes in chicken HD11 cells

Interleukins (ILs) regulate cell surface antigens known as activation markers, which have distinct functional roles. However, the regulation of major histocompatibility complex (MHC) class I, MHC class II, and related genes by cytokines in chickens is not well understood. In the present study, we evaluated the influence of certain recently discovered chicken interleukins-i.e., IL-11, IL-12B, IL-17A, IL-17B, IL-26, and IL-34-on the expression and regulation of genes related to MHC class I, MHC class II, and the associated proteins in an HD11 chicken macrophage cell line. We used quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunocytochemical, and flow cytometric analyses to assess dose- and time-dependent expression in the HD11 cell line and found that the ILs induced MHC class I, MHC class II, and associated protein. As NF-κB is actively involved in cell activation and is constitutively activated in many immune cells, we also determined whether NF-κB regulates MHC class I, MHC class II, and related gene expression in the HD11 cell line. The NF-κB inhibitor sulfasalazine (Sz) dose-dependently inhibited MHC class I and MHC class II in the HD11 cell line. Sz also downregulated the expression of MHC class I, MHC class II, and the associated proteins in the IL-induced HD11 cell line. The expression of MHC class I, MHC class II, and associated genes was accompanied by the Sz-sensitive degradation of the p65 (RelA) and p50 subunits of NF-κB and IκBα. Our results indicate that the different effects of each IL on the expression of genes related to MHC class I, MHC class II, and the associated proteins are involved with the regulation of the dose and duration of antigenic peptide presentation and, thus, also influence Th1, Th2, and Th17 production.