MicroRNAs (miRNAs) have attracted increasing attention for their function in oocyte in vitro maturation (IVM). In this study, we aimed to explore the functional role and underlying mechanism of miR-375 in oocyte IVM. Cumulus-oocyte complexes (COCs) were cultured in standard cell culture conditions until they reach metaphase II (MII) stage. MiR-375 overexpression or knockdown was achieved by corresponding lentiviral transduction. Levels of miR-375, disintegrin and metalloproteinase with thrombospondin-like motifs 1 (ADAMTS1) mRNA and progesterone receptor (PGR) mRNA were detected by qRT-PCR. Western blotting was used to assess the expression of ADAMTS1 and PGR protein. The targeted interaction between miR-375 and ADAMTS1 or PGR was verified by dual-luciferase reporter assay and RNA immunoprecipitation assay. Our results demonstrate that miR-375 is downregulated, and ADAMTS1 and PGR are upregulated in cumulus cells during COC maturation. MiR-375 negatively regulates COC maturation. Moreover, ADAMTS1 and PGR are two targets of miR-375 in cumulus cells. ADAMTS1 or PGR knockdown represses COC maturation and miR-375 inhibits the expression levels of ADAMTS1 and PGR in cumulus cells. Additionally, miR-375 overexpression-mediated suppressive effect on COC maturation is abated by ADAMTS1 or PGR expression restoration. In conclusion, our study suggests that miR-375 represses oocyte IVM at least partially through targeting ADAMTS1 and PGR in cumulus cells, providing a novel insight for the involvement and underlying mechanism of miR-375 in oocyte IVM.
Keywords: ADAMTS1; Cumulus-oocyte complex (COC); Oocyte IVM; PGR; miR-375.
Copyright © 2019 The Authors. Published by Elsevier Masson SAS.. All rights reserved.