Chicken adipose tissue is differentially involved in primary and secondary regional immune response to NDV through miR-20a-5p-NR4A3 pathway.

The mammalian adipose tissue (AT) plays a key role in regulating immune function and anti-infective protection to maintain tissue regional homeostasis. However, it is still unclear whether there are differences in the participation of AT in primary and secondary immune response, and whether avian AT has the similar immune function characteristics to mammals. In this study, we used Newcastle disease virus (NDV) attenuated vaccine to induce primary and secondary immune response in chickens, and the changes of the key regulatory gene NR4A3 (nuclear receptor subfamily 4 group A member 3) of T cells activation and its targeted miR-20a-5p were detected by quantitative real-time PCR (qRT-PCR). The results showed that NR4A3 actively participated in immune response of AT, and showed significant differences in expression activities between the two immune processes. "MiR-20a-5p/NR4A3" pathway was a potential molecular mechanism involved in the regulation of immune function in AT. Moreover, AT responded differently to the primary and secondary immune response possibly through the different patterns of source, apoptosis and migration for lymphocytes (such as CD8β+ T cells). This study can provide directional guidance for further studying immune functions of avian AT.