Bta-miR-10b Secreted by Bovine Embryos Negatively Impacts Preimplantation Embryo Quality.

In a previous study, we found miR-10b to be more abundant in a conditioned culture medium of degenerate embryos compared to that of blastocysts. Here, we show that miR-10b mimics added to the culture medium can be taken up by embryos. This uptake results in an increase in embryonic cell apoptosis and aberrant expression of DNA methyltransferases (). Using several algorithms, Homeobox A1 () was identified as one of the potential miR-10b target genes and dual-luciferase assay confirmed as a direct target of miR-10b. Microinjection of si- into embryos also resulted in an increase in embryonic cell apoptosis and downregulation of . Cell progression analysis using Madin-Darby bovine kidney cells (MDBKs) showed that miR-10b overexpression and knockdown results in suppressed cell cycle progression and decreased cell viability. Overall, this work demonstrates that miR-10b negatively influences embryo quality and might do this through targeting and/or influencing DNA methylation.