Study on the mechanism of miR-7562 regulating ATG5 and ATG12 genes in Penaeus monodon under Vibrio harveyi infection.

MicroRNAs (miRNAs) play a fundamental role in the post-transcriptional regulation of genes and are pivotal in modulating immune responses in marine species, particularly during pathogen assaults. This study focused on the function of miR-7562 and its regulatory effects on autophagy against Vibrio harveyi infection in the black tiger shrimp (Penaeus monodon), an economically important aquatic species. We successfully cloned and characterized two essential autophagy-related genes (ATGs) from P. monodon, PmATG5 and PmATG12, and then identified the miRNAs potentially involved in co-regulating these genes, which were notably miR-7562, miR-8485, and miR-278. Subsequent bacterial challenge experiments and dual-luciferase reporter assays identified miR-7562 as the principal regulator of both genes, particularly by targeting the 3'UTR of each gene. By manipulating the in vivo levels of miR-7562 using mimics and antagomirs, we found significant differences in the expression of PmATG5 and PmATG12, which corresponded to alterations in autophagic activity. Notably, miR-7562 overexpression resulted in the downregulation of PmATG5 and PmATG12, leading to a subdued autophagic response. Conversely, miR-7562 knockdown elevated the expression levels of these genes, thereby enhancing autophagic activity. Our findings further revealed that during V. harveyi infection, miR-7562 continued to influence the autophagic pathway by specifically targeting the ATG5-ATG12 complex. This research not only sheds light on the miRNA-dependent mechanisms governing autophagic immunity in shrimp but also proposes miR-7562 as a promising target for therapeutic strategies intended to strengthen disease resistance within the crustacean aquaculture industry.