The Effect of Increased miR-16-1 Levels in Mouse Embryos on Epigenetic Modification, Target Gene Expression, and Developmental Processes.

Changes in microRNA (miRNA) levels are present in numerous diseases. Although these changes are particularly noted in male infertility, little is known about the effects of increased miR-16-1 in sperm from infertile men. In this study, we assessed the effects of increased mir-16-1 expression on the developmental process, epigenetic changes, and target gene expressions. IVF embryos, 6 h after insemination, were divided into three groups: control, control negative (CN), and miR-16-1 harboring plasmid microinjection. The developmental rates of these embryos were recorded after 24, 48, 72, and 96 h of culture. The levels of histone H3 lysine 4 tri-methylation (H3K4me3) and histone H3 lysine 27 tri-methylation (H3K27me3) were assessed in the 2-cell and blastocyst stages by immunofluorescence staining. Expression profiles of the miR16-1, Bax, Bcl-2, Suz12, and Kmt2a genes were measured by quantitative real-time polymerase chain reaction (qRT-PCR). There was a significant decrease from the 8-cell stage to the blastocyst stage of embryo development in the miR-16-1 harboring plasmid microinjection group. We observed substantial reductions in the amounts of H3K4me3 and H3K27me3 in the 2-cell and the blastocyst stages in the miR-16-1 harboring plasmid microinjection group (P ≤ 0.05). The miR-16-1 level in the miRNA group was higher than the control group in the 2-cell and the blastocyst stages. There was a significant increase (P ≤ 0.05) in Bax and decreases in Bcl2, Suz12, and Kmt2a following the injection of the miR-16-1 harboring plasmid. These results suggest that a change in miR-16-1 expression can significantly affect embryo development, epigenetic changes, and target gene expressions.