AUTHOR=Zhao Tanjun , Ren Liyuan , Li Chengda , Liu Li , Zou Yang , Yan Hanyu , Zhan Yaoyao , Chang Yaqing 

TITLE=MiR-7 Regulates Pathogen-Induced Immune Response via PAK1 in the Sea Cucumber Apostichopus japonicus

JOURNAL=Frontiers in Immunology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.927796

DOI=10.3389/fimmu.2022.927796

ISSN=1664-3224

ABSTRACT=<p>MicroRNA-7 (miR-7) is a highly conserved short non-coding RNA involved in various bioprocesses <italic>via</italic> the regulation of multiple target genes. To enrich our knowledge of the functions of miR-7 in innate immune regulation in echinoderms, we first investigated the targeting relationship between miR-7 and <italic>PAK1</italic> in the sea cucumber <italic>Apostichopus japonicus</italic> and then explored the functions of miR-7, the <italic>PAK1</italic> gene, and the miR-7/<italic>PAK1</italic> axis in the pathogen-induced immune response of <italic>A. japonicus</italic>. Our results showed that miR-7 can bind to the 3ʹUTR of <italic>PAK1</italic> and negatively regulate the expression of <italic>PAK1</italic> in <italic>A. japonicus</italic>. Overexpression and inhibition of miR-7 and inhibition of the expression of <italic>PAK1</italic> can alter phagocytosis, cellular agglutination, and lysozyme contents in <italic>A. japonicus</italic>. Both miR-7 and the <italic>PAK1</italic> gene are involved in immune defense against <italic>Vibrio splendidus</italic> infection; the miR-7/<italic>AjPAK1</italic> axis showed immune regulatory function at 48 to 72 h post-infection (hpi) after <italic>V. splendidus</italic> infection in <italic>A. japonicus.</italic> In summary, the results of this study established that miR-7 regulates the pathogen-induced immune response by targeting <italic>PAK1</italic> in <italic>A. japonicus</italic>.</p>