Ganglioside GD1a promotes oocyte maturation, furthers preimplantation development, and increases blastocyst quality in pigs

Abstract

Gangliosides are key lipid molecules required for the regulation of cellular processes such as proliferation, differentiation, and cell signaling, including signaling of epidermal growth factor receptor (EGFR). Epidermal growth factor (EGF) has long been considered a potential regulator of meiotic and cytoplasmic maturation in mammalian oocytes. However, there is no report on the direct effect of ganglioside GD1a in porcine oocyte maturation. In this study, we first investigated a functional link between GD1a and meiotic maturation during in vitro maturation (IVM) of porcine embryos. Moreover, we confirmed the effect of exogenous GD1a treatment on blastocyst development, quality, and fertilization rate in early embryonic development. First, we observed that the protein level of ST3GAL2, a GD1a synthesizing enzyme, significantly increased (P < 0.01) in cumulus-oocyte-complexes (COCs) during IVM progress. The proportion of arrested germinal vesicles (GV) increased in oocytes treated with EGF+GD1a (41.6 ± 1.5%) at the IVM I stage. Upon completion of meiotic maturation, the proportion of metaphase II (M II) was significantly higher (P < 0.05) in the EGF+GD1a (89.9 ± 3.6%) treated group. After IVF, the percentage of penetrated oocytes was significantly higher (P < 0.05) in the EGF+GD1a (89.1 ± 2.3%) treated group than in the control group. Furthermore, exogenous GD1a treatment improved the developmental competence and quality of blastocysts during preimplantation embryo development stage. These results suggest that ganglioside GD1a may play an important role in IVM mechanisms of porcine maturation capacity. Furthermore, our findings will be helpful for better promoting the embryo development and blastocyst quality in pigs.

Effects of Gangliosides on Spermatozoa, Oocytes, and Preimplantation Embryos

“…Exogenously added GD1a into culture medium promotes oocyte maturation and preimplantation development ability via stimulation of oocyte meiosis and maturation. On the other hand, exogenous GD1a decreases polyspermic fertilization in pigs [102]. Choo et al [82] showed that GD1a is distributed within theca cells, interstitial cells, and oocytes during ovarian maturation in the rat.…”

Lipid Stores and Lipid Metabolism Associated Gene Expression in Porcine and Bovine Parthenogenetic Embryos Revealed by Fluorescent Staining and RNA-seq

“…Most of publications describe GM1, GM3 and GD1a gangliosides as important factors involved in the EGFR (epidermal growth factor receptor) signaling pathway [28]. In porcine embryos, exogenous GD1a supported maturation and blastocyst formation in vitro [29]. Others report GM1 and GM3 expression in theca and cumulus rat cells, while Ju et al correlated GM3 expression with apoptosis in preimplantation mouse embryos [30].…”

Regulation of the Endoplasmic Reticulum Stress by BIP/GRP78 is involved in Meiotic Maturation of Porcine Oocytes In Vitro

“…We performed IVM as described by Kim et al (2016) , but with slight modification. Pig ovaries were collected from a local slaughterhouse and transported to our laboratory at 35 in 0.9% saline supplement with 75 μg/mL potassium penicillin G. Immature cumulus-oocyte-complexes (COCs) between 3 and 6 mm in diameter were aspirated into a 10 mL syringe from ovary follicles by using an 18-gauge needle.…”