Sun Tongzhen, Huang Jinqiang, Li Yongjuan, Wu Shenji, Zhao Lu, Kang Yujun
College of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China.
College of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China.
Comp Biochem Physiol Part D Genomics Proteomics. 2024 Dec;52:101277. doi: 10.1016/j.cbd.2024.101277. Epub 2024 Jun 18.
Rainbow trout (Oncorhynchus mykiss) is an economically significant freshwater-farmed fish worldwide, and the frequent outbreaks of infectious hematopoietic necrosis (IHN) in recent years have gravely compromised the healthy growth of the rainbow trout aquaculture industry. Fish skin is an essential immune barrier against the invasion of external pathogens, but it is poorly known about the role of circRNAs in rainbow trout skin. Therefore, we examined the expression profiles of circRNAs in rainbow trout skin following IHNV infection using RNA-seq. A total of 6607 circRNAs were identified, of which 34 circRNAs were differentially expressed (DE) and these DE circRNA source genes were related to immune-related pathways such as Toll-like receptor signaling pathway, NOD-like receptor signaling pathway, Cytokine-cytokine receptor interaction, ubiquitin mediated proteolysis, and ferroptosis. We used qRT-PCR, Sanger sequencing, and subcellular localization to validate the chosen DE circRNAs, confirming their localization and expression patterns in rainbow trout skin. Further, 12 DE circRNAs were selected to construct the circRNA-miRNA-mRNA regulatory network, finding one miRNA could connect one or more circRNAs and mRNAs, and some miRNAs were reported to be associated with antiviral immunity. The functional prediction findings revealed that novel_circ_002779 and novel_circ_004118 may act as sponges for miR-205-z and miR-155-y to regulate the expression of target genes TLR8 and PIK3R1, respectively, and participated in the antiviral immune responses in rainbow trout. These results shed light on the immunological mechanism of circRNAs in rainbow trout skin and offer fundamental information for further research on the innate immune system and breeding rainbow trout resistant to disease.
虹鳟（Oncorhynchus mykiss）是全球具有重要经济意义的淡水养殖鱼类，近年来传染性造血坏死（IHN）的频繁爆发严重影响了虹鳟养殖业的健康发展。鱼皮是抵御外部病原体入侵的重要免疫屏障，但关于环状RNA（circRNAs）在虹鳟鱼皮肤中的作用却知之甚少。因此，我们利用RNA测序技术检测了虹鳟鱼感染传染性造血坏死病毒（IHNV）后皮肤中circRNAs的表达谱。共鉴定出6607个circRNAs，其中34个circRNAs差异表达（DE），这些DE circRNA的来源基因与免疫相关途径有关，如Toll样受体信号通路、NOD样受体信号通路、细胞因子-细胞因子受体相互作用、泛素介导的蛋白水解和铁死亡。我们使用qRT-PCR、Sanger测序和亚细胞定位来验证所选的DE circRNAs，证实它们在虹鳟鱼皮肤中的定位和表达模式。此外，选择12个DE circRNAs构建circRNA-miRNA-mRNA调控网络，发现一个miRNA可以连接一个或多个circRNAs和mRNAs，并且一些miRNAs被报道与抗病毒免疫有关。功能预测结果表明，新型_circ_002779和新型_circ_004118可能分别作为miR-205-z和miR-155-y的海绵，调节靶基因TLR8和PIK3R1的表达，并参与虹鳟鱼的抗病毒免疫反应。这些结果揭示了circRNAs在虹鳟鱼皮肤中的免疫机制，为进一步研究先天免疫系统和培育抗病虹鳟鱼提供了基础信息。
