【 TITLE 】Exogenous Ganglioside GT1b Enhances Porcine Oocyte Maturation, Including the Cumulus Cell Expansion and Activation of EGFR and ERK1/2 Signaling

【 JOURNAL 】Reproductive Sciences

​【 NAME 】Jin-Woo Kim, Hyo-Jin Park, Seul-Gi Yang, Min-Ji Kim, In-Su Kim, Ho-Geun Jegal, Gabbine Wee, Hee-Young Yang, Joung Jun Park, Young-Kug Choo and Deog-Bon Koo

【 PUBLISHED 】01 January 2020

【 ISSN 】1933-7205

【 DOI 】https://doi.org/10.1007/s43032-019-00004-9

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【 ABSTRACT 】

 Ganglioside GT1b is well-known for its role in cytokine production and in activating epidermal growth factor receptor (EGFR)-mediated signaling pathways in cancer cells. However, there are no reports that clearly elucidate the role of GT1b in EGFR-mediated signaling pathways in porcine oocytes during the process of in vitro maturation (IVM). In this study, we investigated the role of GT1b in EGFR-mediated activation of the ERK1/2 pathway in porcine cumulus-oocyte complexes (COCs) at 44 h of IVM. Our data show that expression of the ST3GAL2 protein significantly increased in porcine COCs at 44 h irrespective of treatment with EGF. Meiotic maturation and mRNA levels of factors (HAS2, TNFAIP6, and PTX3) related to cumulus cell expansion significantly increased in COCs treated with 2 μM GT1b during IVM in the absence of EGF. They also increased in COCs treated with EGF/GT1b as compared to that in the other groups. Interestingly, protein levels of EGFR, phospho-EGFR, ERK1/2, and phospho-ERK1/2 dramatically increased in COCs treated with EGF/GT1b. Moreover, the rate of fertilization and the developmental competence of blastocyst were significantly higher in EGF/GT1b-treated COCs. Taken together, these results suggest that exogenous GT1b improves meiotic maturation and cumulus cell expansion in porcine COCs via activation of EGFR-mediated ERK1/2 signaling.​​

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【 KEYWORDS 】Ganglioside GT1b . ST3GAL2 . EGFR signaling . ERK . Porcine oocyte maturation