Inducible microRNA-122 modulates RIG-I signaling pathway via targeting DAK in miiuy croaker after poly(I:C)...

Area of Science:

• * Molecular Biology
• * Immunology
• * Fish Biology

Background:

• * MicroRNA-122 (miR-122) is well-studied in mammals but less understood in fish.
• * miR-122 in miiuy croaker shows sensitivity to poly(I:C) stimulation, suggesting immune relevance.
• * Functional studies of miR-122 in fish immunity are limited.

Purpose of the Study:

• * To investigate the functions of miR-122 in miiuy croaker.
• * To identify and validate target genes of miR-122 involved in immune pathways.
• * To elucidate the role of miR-122 in regulating the RIG-I-like receptor signaling pathway.

Main Methods:

• * Bioinformatics prediction of miR-122 target genes.
• * Luciferase reporter assays to confirm DAK as a direct target of miR-122.
• * Experimental validation using miR-122 mimics and pre-miR-122 to assess inhibition of DAK.
• * Analysis of the relationship between miR-122 and DAK expression in miiuy croaker tissues and cells.

Main Results:

• * DAK was identified as a putative target gene of miR-122.
• * Luciferase assays confirmed miR-122 binding sites in the 3' untranslated region of DAK.
• * miR-122 mimics and pre-miR-122 demonstrated dose- and time-dependent inhibition of DAK expression.
• * Pre-miR-122 exhibited a stronger inhibitory effect on DAK than miR-122 mimics.
• * A negative correlation between miR-122 and DAK expression was observed in miiuy croaker spleen and macrophages.
• * miR-122 regulates the RIG-I-like receptor signaling pathway by inhibiting DAK, an inhibitor of MDA5.

Conclusions:

• * miR-122 plays a crucial role in the immune response of miiuy croaker.
• * miR-122 targets and inhibits DAK at the post-transcriptional level.
• * This regulation impacts the RIG-I-like receptor signaling pathway via modulation of MDA5 activity.
• * Findings enhance understanding of miRNA-mediated immune regulation in fish.