Transcriptome analysis of chicken intraepithelial lymphocyte natural killer cells infected with very virulent infectious bursal disease virus

Serum metabolic alterations in chickens upon infectious bursal disease virus infection

BACKGROUND

Infectious bursal disease virus (IBDV) is a highly contagious immunosuppressive virus of chickens. Chickens acquire infection by the oral route under natural conditions. Although the histological and pathological changes after IBDV infection are well described, the alterations in serum metabolome have not been reported. In this study, SPF chickens were infected with attenuated IBDV (atIBDV) strain LM and very virulent IBDV (vvIBDV) strain LX, respectively. On the seventh day after oral infection, serum samples of experimental chickens were identified using ultra-high performance liquid chromatography-MS/MS (UHPLC-MS/MS). The serum metabolic profiles were analyzed by multivariate statistical methods. KEGG enrichment analysis was performed to evaluate the dysregulated biological pathways.

RESULTS

We identified 368 significantly altered metabolites in response to both atIBDV and vvIBDV infection. The metabolic disorder of amino acid and lipid was associated with IBDV infection, especially tryptophan, glycerophospholipid, lysine, and tyrosine metabolism. The differential metabolites enriched in the four metabolic pathways were PC(20:4(5Z,8Z,11Z,14Z)/18:0), PE(16:0/18:2(9Z,12Z)), PE(16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), PE(18:0/20:4(5Z,8Z,11Z,14Z)), PE(18:0/20:4(8Z,11Z,14Z,17Z)), PE(18:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), PE(20:3(8Z,11Z,14Z)/16:0), PE(22:6(4Z,7Z,10Z,13Z,16Z,19Z)/16:0), PE-NMe(20:5(5Z,8Z,11Z,14Z,17Z)/18:0), PS(20:3(5Z,8Z,11Z)/18:2(9Z,12Z)), 2-aminobenzoic acid, 4-(2-aminophenyl)-2,4-dioxobutanoic acid, N-acetylserotonin, 5-hydroxyindoleacetate, indole-3-acetaldehyde, indole-3-acetate, p-coumaric acid, L-tyrosine, homovanillin, and S-glutaryldihydrolipoamide.

CONCLUSION

The atIBDV and vvIBDV infection causes metabolic changes in chicken serum. The differential metabolites and dysregulated metabolic pathways reflect the host response to the IBDV infection.

RNA-seq reveals role of cell-cycle regulating genes in the pathogenicity of a field very virulent infectious bursal disease virus

Infectious bursal disease virus (IBDV) infection causes highly contagious and immunosuppressive disease in poultry. The thymus, serving as the primary organ for T cell maturation and differentiation, plays an important role in the pathogenicity of IBDV in the infected chickens. However, there are no reports on the molecular pathogenesis of IBDV in the thymus currently. The aim of the study was to elucidate the molecular mechanisms underlying the pathogenicity of a field very virulent (vv) IBDV strain NN1172 in the thymus of SPF chickens using integrative transcriptomic and proteomic analyses. Our results showed that a total of 4,972 Differentially expressed genes (DEGs) in the thymus of NN1172-infected chickens by transcriptomic analysis, with 2,796 up-regulated and 2,176 down-regulated. Meanwhile, the proteomic analysis identified 726 differentially expressed proteins (DEPs) in the infected thymus, with 289 up-regulated and 437 down-regulated. Overall, a total of 359 genes exhibited differentially expression at both mRNA and protein levels, with 134 consistently up-regulated and 198 genes consistently down-regulated, as confirmed through a comparison of the RNA-seq and the proteomic datasets. The gene ontology (GO) analysis unveiled the involvement of both DEGs and DEPs in diverse categories encompassing cellular components, biological processes, and molecular functions in the pathological changes in IBDV-infected thymus. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the host mainly displayed severely disruption of cell survival/repair, proliferation and metabolism pathway, meanwhile, the infection triggers antiviral immune activation with a potential emphasis on the MDA5 pathway. Network inference analysis identified seven core hub genes, which include CDK1, TYMS, MCM5, KIF11, CCNB2, MAD2L1, and MCM4. These genes are all associated with cell-cycle regulating pathway and are likely key mediators in the pathogenesis induced by NN1172 infection in the thymus. This study discovered dominant pathways and genes which enhanced our understanding of the molecular mechanisms underlying IBDV pathogenesis in the thymus.

Cytokines, Serological, and Histopathological Assessment of Recombinant Vaccination Strategies for Combatting Infectious Bursal Disease in Broiler Chickens

Infectious bursal disease (IBD) represents a greatly transmissible viral disease found worldwide, causing significant health and production challenges in young chickens. The aim of this research was to assess the immune reaction induced by different vaccines targeting IBD. These vaccines included recombinant (Vac1; HVT-IBD vector), immune complex (Vac2; Bursa-Plex®), and intermediate plus (Vac3; Bursine plus) IBD vaccines. Our assessment relied on serological and histopathological analyses, as well as the pattern of immune-related cytokine expression in the bursal tissue. The vaccinated groups, along with a control positive (CP) group, were subjected to a vvIBDV challenge on their 28th day of life, while the control negative (CN) group received a mock vaccination with PBS. Our study revealed that Vac1 resulted in the most favorable growth performance, as well as maintained normal liver and kidney function, mitigating the impact of IBDV infection. Serological analysis using VP2 ELISA kits indicated that Vac1 induced the strongest immunological response among all vaccines. Histopathological examination demonstrated that Vac1 caused minimal lymphoid depletion observed in the lymphoid organs, followed by Vac2. Analysis of cytokine expression profiles showed significant upregulation in all vaccinated groups, particularly Vac1, during the pre-challenge period. Following IBDV infection, Vac1 resulted in a noteworthy increase in the expression of IL2 and IFN-γ, Vac2 showed a significant upregulation in TNF-α and granzyme, and both Vac1 and Vac3 exhibited increased levels of IL1β and IL10. In conclusion, our study suggests that the various vaccines triggered immune responses against IBD through both humoral and cell-mediated immunity. However, recombinant followed by immune complex vaccines appeared to induce more robust immunity while also being safer for broiler chickens in contrast to the intermediate plus vaccine.

DNA methylome and transcriptome identified Key genes and pathways involved in Speckled Eggshell formation in aged laying hens

BACKGROUND

The quality of poultry eggshells is closely related to the profitability of egg production. Eggshell speckles reflect an important quality trait that influences egg appearance and customer preference. However, the mechanism of speckle formation remains poorly understood. In this study, we systematically compared serum immune and antioxidant indices of hens laying speckled and normal eggs. Transcriptome and methylome analyses were used to elucidate the mechanism of eggshell speckle formation.

RESULTS

The results showed that seven differentially expressed genes (DEGs) were identified between the normal and speckle groups. Gene set enrichment analysis (GSEA) revealed that the expressed genes were mainly enriched in the calcium signaling pathway, focal adhesion, and MAPK signaling pathway. Additionally, 282 differentially methylated genes (DMGs) were detected, of which 15 genes were associated with aging, including ARNTL, CAV1, and GCLC. Pathway analysis showed that the DMGs were associated with T cell-mediated immunity, response to oxidative stress, and cellular response to DNA damage stimulus. Integrative analysis of transcriptome and DNA methylation data identified BFSP2 as the only overlapping gene, which was expressed at low levels and hypomethylated in the speckle group.

CONCLUSIONS

Overall, these results indicate that aging- and immune-related genes and pathways play a crucial role in the formation of speckled eggshells, providing useful information for improving eggshell quality.

Infectious bursal disease virus' interferences with host immune cells: What do we know?

AbstractInfectious bursal disease virus (IBDV) induces one of the most important immunosuppressive diseases in chickens leading to high economic losses due increased mortality and condemnation rates, secondary infections and the need for antibiotic treatment. Over 400 publications have been listed in PubMed.gov in the last five years pointing out the research interest in this disease and the development of improved preventive measures. While B cells are the main target cells of the virus, also other immune and non-immune cell populations are affected leading a multifaceted impact on the normally well orchestrated immune system in IBDV-infected birds. Recent studies clearly revealed the contribution of innate immune cells as well as T cells to a cytokine storm and subsequent death of affected birds in the acute phase of the disease. Transcriptomics identified differential regulation of immune related genes between different chicken genotypes as well as virus strains, which may be associated with a variable disease outcome. The recent availability of primary B cell culture systems allowed a closer look into virus-host interactions during IBDV-infection. The new emerging field of research with transgenic chickens will open up new opportunities to understand the impact of IBDV on the host also under in vivo conditions, which will help to understand the complex virus-host interactions further.

Epididymal mRNA and miRNA transcriptome analyses reveal important genes and miRNAs related to sperm motility in roosters

Sperm motility is a crucial trait in chicken production, and the epididymis is an essential organ in the reproductive system. Currently, the molecular mechanisms underlying sperm motility in the epididymis are unclear. In this study, 8 cDNA libraries and eight miRNA libraries were constructed from roosters (4 chickens per group) with diverse sperm motility. After a comparative analysis of epididymal transcriptomes, we detected 84 differentially expressed genes (DEGs) using the edgeR package. Integrated interpretation of DEGs indicated that MMP9, SLN, WT1, PLIN1, and LRRIQ1 are the most promising candidate genes affecting sperm motility in the epididymis of roosters. MiR-146a, mir-135b, and mir-205 could play important regulatory roles in sperm maturation, capacitation, and motility. Additionally, a comprehensive analysis of the mRNA and miRNAs transcriptomes in silico identified a promising gene-miRNA pair miR-135b-HPS5, which may be a vital regulator of sperm motility in the epididymis. Our findings provide novel integrated information of miRNAs and genes that shed light on the regulatory mechanisms of fertility in roosters.

Comparative bursal cytokine gene expression and apoptosis in vaccinated chickens following virulent infectious bursal disease virus challenge

The bursal cytokine gene expression and apoptosis were compared in vaccinated chickens with either live or immune-complex infectious bursal disease virus (IBDV) vaccines with or without virulent IBDV challenge. The cytokine gene expressions were evaluated at 5 and 12 day-post-challenge (DPC). The apoptotic marker Caspase-3 was determined by IHC on collected bursae, thymus, spleen, and kidneys at 12 DPC. A significantly decreased bursal cytokine levels were observed in the all-vaccinated birds except for IL-6 in the classic IBD vaccines at 5DPC. A significant upregulation of the IL-2 was observed in the live IBD vaccinated birds. No significant differences in the bursa and thymus Caspase-3 positive cells. However, splenic and renal apoptosis was significantly higher in the live IBD vaccine groups. Results indicate that both vaccine types reduce the IBDV-induced bursal proinflammatory cytokines and apoptosis. However, classic IBD vaccines failed to clear the challenge virus or reduce splenic and renal apoptosis.