抗菌肽对免疫系统发挥广泛调节作用，具有佐剂活性，但分子机制尚不明确。circRNA的发现重塑了分子调控理论的原有框架，为佐剂活性机制解析提供了新思路。前期研究发现牛源抗菌肽BSN-37对DCs表面共刺激分子有明显上调作用。我们推测特定circRNAs在佐剂（抗菌肽）激活机体免疫应答过程中发挥关键作用。本项目拟以BSN-37为研究对象，体外检测其对BMDCs、RAW264.7成熟和功能的影响，体内探索其对OVA疫苗、仔猪大肠埃希氏菌病三价灭活疫苗佐剂活性；采用芯片技术检测BSN-37对RAW264.7与腹腔巨噬细胞基因表达谱的影响，分析差异表达circRNA和mRNA，构建“circRNA-mRNA”和“circRNA-miRNA-mRNA”网络图，对候选circRNA(s)开展系统鉴定和功能解析，阐明其序列结构信息、特性及生物学功能，以期为开发安全、有效的新型抗菌肽类佐剂提供理论依据。

Antimicrobial peptides can regulate the immune system extensively. Their adjuvant activity has been confirmed, but the underlying mechanisms remain unclear. The discovery of circRNA reshapes the original framework of molecular regulation theory and provides new ideas for the analysis of adjuvant mechanism. Our previous studies have found that BSN-37, a bovine erythrocyte-derived antimicrobial peptide analogue, can significantly up-regulate costimulatory molecules on the dendritic cells. Based on the research progress by others and our preliminary work, we speculate that some specific circRNAs play key roles in the activation of immune response by adjuvant (BSN-37). Therefore, this project will take BSN-37 as the research object to test its effect on maturation and function of BMDCs and RAW264.7 in vitro, and explore its adjuvant effect on OVA protein vaccine and trivalent inactivated vaccine of piglet E. coli in vivo. The gene expression profiles of BSN-37 treated RAW264.7 macrophages and peritoneal macrophages in mice after intraperitoneal injection of BSN-37 will be taken to screen and analyze differentially expressed circRNA and mRNA for constructing a co-expression network of "circRNA-RNA" and a ternary network of "circRNA-microRNA-RNA" and discovering new circRNA(s) with immunoregulatory activity. In this project we will also carry out systematic identification and functional analysis to clarify the sequence structure information, characteristics and biological functions of these new circRNA(s). Our finding will provide the necessary theoretical basis for the development of safe and effective new antimicrobial peptide adjuvants.