Regional immunity of chicken adipose tissue responds to secondary immunity induced by Newcastle disease vaccine via promoting immune activation and weakening lipid metabolism

Adipose tissue (AT) is considered as a regional immune organ and plays an important role in the anti-infection immune response. However, the func-tion and mechanism of chicken AT in response to sec-ondary immune response remain poorly understood. Here, we used mRNA and microRNA (miRNA) sequencing technology to survey the transcriptomic landscape of chicken abdominal adipose tissue (AAT) during the first and second immunization with Newcas-tle disease virus (NDV) vaccine, and carried out bioin-formatics analysis, such as Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis, protein-pro-tein interaction (PPI) analysis, and miRNA-mRNA integrated analysis. The results indicated that chicken AAT actively responded to the secondary immune response. DNA replication and cytoskeleton regulation as the regulatory functions of immune activation changed significantly, and weakened lipid metabolism was an effective strategy for the secondary immunity. Mechanically, the regulatory network between the dif-ferentially expressed miRNAs (DEMs) and their tar-geted differentially expressed genes (DEGs), such as miR-206/miR-499-5p-nuclear receptor subfamily 4 group A member 3 (NR4A3)/methylsterol monooxyge-nase 1 (MSMO1) pathway, was one of the potential key mechanisms by which AAT responded to the sec-ondary immune response. In conclusion, regional immu-nity of chicken AT responds to secondary immunity by promoting immune activation and weakening lipid metabolism, and this study can instruct future research on antiviral strategy.