Abstract：
The hepatopancreas is the biggest digestive organ in Amphioctopus fangsiao (A. fangsiao), but also undertakes critical functions like detoxification and immune defense. Generally, pathogenic bacteria or endotoxin from the gut microbiota would be arrested and detoxified in the hepatopancreas, which could be accompanied by the inevitable immune responses. In recent years, studies related to cephalopods immune have been increasing, but the molecular mechanisms associated with the hepatopancreatic immunity are still unclear. In this study, lipopolysaccharide (LPS), a major component of the cell wall of Gram-negative bacteria, was used for imitating bacteria infection to stimulate the hepatopancreas of A. fangsiao. To investigate the immune process happened in A. fangsiao hepatopancreas, we performed transcriptome analysis of hepatopancreas tissue after LPS injection, and identified 2615 and 1943 differentially expressed genes (DEGs) at 6 and 24 h post-injection, respectively. GO and KEGG enrichment analysis showed that these DEGs were mainly involved in immune-related biological processes and signaling pathways, including ECM-receptor interaction signaling pathway, Phagosome signaling pathway, Lysosome signaling pathway, and JAK-STAT signaling pathways. The function relationships between these DEGs were further analyzed through protein-protein interaction (PPI) networks. It was found that Mtor, Mapk14 and Atm were the three top interacting DEGs under LPS stimulation. Finally, 15 hub genes involving multiple KEGG signaling pathways and PPI relationships were selected for qRT-PCR validation. In this study, for the first time we explored the molecular mechanisms associated with hepatopancreatic immunity in A. fangsiao using a PPI networks approach, and provided new insights for understanding hepatopancreatic immunity in A. fangsiao.
摘要：
肝胰腺是两栖动物中最大的消化器官（A.fangsiao),而且还承担着排毒和免疫防御等关键功能。一般来说,来自肠道微生物群的致病菌或内毒素将在肝胰腺中被阻止和解毒，这可能伴随着不可避免的免疫反应。近年来,与头足类动物免疫相关的研究一直在增加，但与肝胰腺免疫相关的分子机制仍不清楚。在这项研究中,脂多糖（LPS），革兰氏阴性细菌细胞壁的主要成分，用于模拟细菌感染以刺激A.fangsiao的肝胰腺。目的探讨方小肝胰腺的免疫过程,我们对LPS注射后的肝胰腺组织进行了转录组分析，并在注射后6和24小时鉴定了2,615和1,943个差异表达基因（DEG），分别。GO和KEGG富集分析表明,这些DEGs主要参与免疫相关的生物过程和信号通路,包括ECM-受体相互作用信号通路，吞噬体信号通路,溶酶体信号通路,和JAK-STAT信号通路。通过蛋白质-蛋白质相互作用（PPI）网络进一步分析了这些DEG之间的功能关系。发现Mtor,Mapk14和Atm是LPS刺激下三个最高相互作用的DEG。最后,选择涉及多个KEGG信号通路和PPI关系的15个hub基因用于qRT-PCR验证。在这项研究中,我们首次使用PPI网络方法探索了与A.fangsiao的肝胰腺免疫相关的分子机制，并为理解方小肝胰腺免疫提供了新的见解。
