Integrated analysis of microRNA expression profiles in Takifugu obscurus kidney following Vibrio harveyi challenge

Abstract

MicroRNAs (miRNAs), a class of small non-coding RNAs critical for post-transcriptional gene regulation, serve as key immune modulators in vertebrates. However, their roles in teleost disease resistance remain underexplored. In the present study, a comprehensive miRNA transcriptome analysis was conducted in Takifugu obscurus under Vibrio harveyi challenge using high-throughput RNA sequencing. Three miRNA libraries (ToCG, ToEG1, and ToEG2) were constructed from kidney tissues of T. obscurus collected at 0 h (non-infected control), 6 h, and 24 h post-infection. Bioinformatics analysis identified 1093 miRNAs, including 195 novel miRNAs, and revealed 175 differentially expressed miRNAs (DEmiRNAs) across infection timepoints. Validation experiments via quantitative real-time PCR confirmed the expression patterns of 16 randomly selected DEmiRNAs, demonstrating high consistency with sequencing data. Functional enrichment analysis of DEmiRNAs highlighted significant associations with immune regulatory pathways, including mitogen-activated protein kinase signaling, Forkhead box O signaling, erythroblastic leukemia viral oncogene homolog signaling, and endocytosis pathways. Notably, several DEmiRNAs exhibited temporal expression patterns, suggesting stage-specific immunoregulatory functions during bacterial pathogenesis. This study suggests a potential miRNA regulatory network in T. obscurus during V. harveyi infection, providing crucial insights into conserved and species-specific miRNA-mediated immune mechanisms in teleosts.