#136 : Osteopontin Facilitates Embryo Growth, Implantation, and Cellular Metabolism via Interacting with v3 and RGS2 Pathway: Evidence from Mouse Embryos and a 3D In-Vitro Implantation Model

Background and Aims: We conducted a study on mice to investigate how osteopontin, a mediator of cell-cell and cell-extracellular matrix (ECM) communication and invasion, influences embryonic development, metabolism, and implantation potential, with confirmation by a 3D in-vitro implantation model. Method: Embryos were collected from female mice and cultured under different conditions: HTF only, HTF supplemented with OPN at different doses, and OPN-supplemented HTF with anti-[Formula: see text]v[Formula: see text]3 Ab or RGS2 inhibitors. Embryo morphology, development, and implantation rates were evaluated. Microarrays were used to evaluate gene expression profiling. Choriocarcinoma JAR and epithelial RL95-2 cell lines were adopted for the in-vitro implantation model. Oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were used to measure cellular metabolism levels. Results: The supplementation of OPN best enhanced the rate of embryo hatching-out and implantation onto the matrigel at 100 nM, but a higher degeneration rate was seen at a higher concentration ([Formula: see text]200 nM). In OPN-treated embryos, microarray analysis showed 51 significantly down-regulated genes and 60 up-regulated genes, including RGS2. Inhibition of [Formula: see text]v[Formula: see text]3 integrin decreased embryo implantation rates and down-regulated RGS2. Validation of the 3D implantation model using JAR spheroids and RL95-2 monolayer showed a similar effect. OPN also increased OCR and ECAR of the JAR cells, and migration assays revealed increased migration ability in OPN-overexpressed JAR cells, which was then inhibited by [Formula: see text]v[Formula: see text]3 and RGS2 inhibitors. Conclusion: Osteopontin, at a reasonable concentration, could enhance embryo development and implantation by interacting with [Formula: see text]v[Formula: see text]3 integrin, subsequently facilitating the RGS2 pathway. OPN has the potential to be a supplement during in vitro embryo culture in ART intervention.