Zheng Tao, Tao Yifan, Lu Siqi, Qiang Jun, Xu Pao
School of Fisheries, Lu Dong University, Yantai, 264025, China.
Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
BMC Genomics. 2025 Jul 1;26(1):582. doi: 10.1186/s12864-025-11757-w.
Fish transportation, a routine operation in aquaculture, can induce immune responses in fish, potentially affecting their health. Nevertheless, the immune response mechanisms involved in microRNAs (miRNAs) under transport stress remain unclear. Therefore, we investigated the immune response strategy of miRNAs in intestines of hybrid yellow catfish under transport stress via physiological, biochemical and RNA-seq analysis. We found that transportation induced innate immune response of intestines characterized by significant increases in alkaline phosphatase, acid phosphatase, lysozyme, and complement 3 level. Meanwhile, 50 differentially expressed miRNAs were identified and comprehensive analysis of miRNA-mRNA sequencing showed their targets genes involved in 9 immune-related pathways. Notably, the miRNAs involved in immune regulation, such as miR-29a/b, miR-106, miR-454-3p and miR-455, were notably upregulated following the induction of transport stress, while miR-196a-5p was significantly downregulated. In addition, their corresponding target genes such as tkt, mafg, arap2, nfatc2, egr2 and wnk4 showed opposite expression trends, suggesting that these genes may be the key immunomodulatory targets of corresponding miRNA. Here, we focused on the regulatory function of miR-455 and its predictive target genes egr2. Double luciferase assay revealed that miR-455 might exist binding site in the 3'-UTR sequence of egr2 mRNA. Interestingly, silencing miR-455 under transport stress led to the increase of intestinal egr2 expression, affected intestinal immune and inflammation responses, and caused intestinal tissue damage and abnormal secretion of mucous substances. In conclusion, transport stress triggered intestinal immune response, and multiple miRNAs played important role in immune response, among which miR-455 might be an important biomarker. These findings not only improve the understanding of the immunomodulatory function of miRNA in fish, but also provide a theoretical basis for screening potential regulatory targets under transport stress.
鱼类运输是水产养殖中的一项常规操作，可诱导鱼类产生免疫反应，这可能会影响它们的健康。然而，运输应激下微小RNA（miRNA）所涉及的免疫反应机制仍不清楚。因此，我们通过生理、生化和RNA测序分析，研究了杂交黄颡鱼在运输应激下肠道中miRNA的免疫反应策略。我们发现，运输诱导了肠道的固有免疫反应，其特征是碱性磷酸酶、酸性磷酸酶、溶菌酶和补体3水平显著升高。同时，鉴定出50个差异表达的miRNA，对miRNA-mRNA测序的综合分析表明，它们的靶基因涉及9条免疫相关途径。值得注意的是，参与免疫调节的miRNA，如miR-29a/b、miR-106、miR-454-3p和miR-455，在运输应激诱导后显著上调，而miR-196a-5p则显著下调。此外，它们相应的靶基因，如tkt、mafg、arap2、nfatc2、egr2和wnk4，表现出相反的表达趋势，表明这些基因可能是相应miRNA的关键免疫调节靶点。在此，我们重点研究了miR-455及其预测靶基因egr2的调控功能。双荧光素酶测定表明，miR-455可能在egr2 mRNA的3'-UTR序列中存在结合位点。有趣的是，在运输应激下沉默miR-455会导致肠道egr2表达增加，影响肠道免疫和炎症反应，并导致肠道组织损伤和黏液物质分泌异常。总之，运输应激引发了肠道免疫反应，多种miRNA在免疫反应中发挥了重要作用，其中miR-455可能是一个重要的生物标志物。这些发现不仅增进了对鱼类中miRNA免疫调节功能的理解，也为筛选运输应激下潜在的调控靶点提供了理论依据。
