Li Yongjuan, Wu Shenji, Huang Jinqiang, Zhao Lu
College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China.
College of Science, Gansu Agricultural University, Lanzhou, 730070, China.
BMC Genomics. 2024 Dec 2;25(1):1163. doi: 10.1186/s12864-024-11019-1.
Hypoxia negatively affects the behavior, growth, reproduction and survival of fish, causing serious economic losses to aquaculture. Rainbow trout (Oncorhynchus mykiss), an important economic fish worldwide, belongs to a hypoxia-sensitive fish species, however, little is known about the regulatory mechanism of microRNAs (miRNAs) under hypoxia stress.
Rainbow trout were subjected to hypoxia stress for 3 h (H3h_L), 12 h (H12h_L), 24 h (H24h_L) and 3 h reoxygenation (R3h_L) to systemically evaluate the changes of miRNA expression profiles in liver, and functions of sha-miR-92a_L + 2R + 4 were investigated. We found 17, 144, 57 and 55 differentially expressed (DE) miRNAs in the H3h_L vs. control (N_L), H12h_L vs. N_L, H24h_L vs. N_L and R3h_L vs. N_L comparisons, respectively. Enrichment analysis revealed that the targets of DE miRNAs were significantly enriched in HIF signaling pathway, VEGF signaling pathway, FoxO signaling pathway and glycolysis/gluconeogenesis. Through miRNA-mRNA interaction and weighted gene co-expression network analysis (WGCNA), five key DE miRNAs (sha-miR-92a_L + 2R + 4, ssa-miR-128-3p, ssa-miR-101b-3p_R + 1, ola-miR-199a-5p_R + 2 and tni-miR-199_1ss18CG) were identified, which can target at least two hypoxia-responsive genes, such as vegfaa, ho, glut1a and junb. Functional analysis found that sha-miR-92a_L + 2R + 4 directly regulated vegfaa expression by targeting its 3'-UTR, overexpression of sha-miR-92a_L + 2R + 4 significantly decreased vegfaa expression in rainbow trout liver cells, while opposite results were obtained after transfection of sha-miR-92a_L + 2R + 4 inhibitor. Furthermore, overexpressed sha-miR-92a_L + 2R + 4 promoted rainbow trout liver cell proliferation and inhibited apoptosis.
This study deepens our understanding of the crucial roles of miRNAs under hypoxia stress in rainbow trout. These results can contribute to devise strategies for improving rainbow trout survival rate and aquaculture production during hypoxia stress and help speeding up the selective breeding of hypoxia-tolerant rainbow trout.
缺氧会对鱼类的行为、生长、繁殖和生存产生负面影响，给水产养殖业造成严重经济损失。虹鳟（Oncorhynchus mykiss）是全球重要的经济鱼类，属于对缺氧敏感的鱼类品种，然而，关于缺氧胁迫下微小RNA（miRNA）的调控机制知之甚少。
对虹鳟进行3小时（H3h_L）、12小时（H12h_L）、24小时（H24h_L）的缺氧胁迫以及3小时的复氧处理（R3h_L），以系统评估肝脏中miRNA表达谱的变化，并研究sha-miR-92a_L + 2R + 4的功能。我们分别在H3h_L与对照组（N_L）、H12h_L与N_L、H24h_L与N_L以及R3h_L与N_L的比较中发现了17、144、57和55个差异表达（DE）的miRNA。富集分析表明，DE miRNA的靶标在缺氧诱导因子（HIF）信号通路、血管内皮生长因子（VEGF）信号通路、叉头框蛋白O（FoxO）信号通路以及糖酵解/糖异生途径中显著富集。通过miRNA-信使核糖核酸（mRNA）相互作用和加权基因共表达网络分析（WGCNA），鉴定出五个关键的DE miRNA（sha-miR-92a_L + 2R + 4、ssa-miR-128-3p、ssa-miR-101b-3p_R + 1、ola-miR-199a-5p_R + 2和tni-miR-199_1ss18CG），它们可以靶向至少两个缺氧反应基因，如血管内皮生长因子A（vegfaa）、血红素加氧酶（ho）、葡萄糖转运蛋白1a（glut1a）和原癌基因b（junb）。功能分析发现，sha-miR-92a_L + 2R + 4通过靶向vegfaa的3'-非翻译区（UTR）直接调节vegfaa的表达，sha-miR-92a_L + 2R + 4的过表达显著降低了虹鳟肝细胞中vegfaa的表达，而转染sha-miR-92a_L + 2R + 4抑制剂后则得到相反的结果。此外，过表达的sha-miR-92a_L + 2R + 4促进了虹鳟肝细胞的增殖并抑制了细胞凋亡。
本研究加深了我们对虹鳟在缺氧胁迫下miRNA关键作用的理解。这些结果有助于制定策略，以提高虹鳟在缺氧胁迫期间的存活率和水产养殖产量，并有助于加速耐缺氧虹鳟的选育。
