GPR30-mediated the MEK/ERK signaling pathway promotes porcine oocyte maturation and development.

The G protein-coupled receptor 30 (GPR30) exhibits specific expression in oocytes and plays a pivotal role in regulating mammalian oocyte maturation. However, the molecular mechanisms underlying GPR30-mediated porcine oocyte maturation remain poorly characterized. This study elucidated the regulatory function of GPR30 during in vitro maturation (IVM) of porcine oocytes and its potential mechanistic basis. Western blot levels of GPR30 showed that GPR30 protein content decreased with time during oocyte development; however, the addition of 17β-estradiol for 24 h of incubation significantly increased GPR30 in porcine oocytes. At the same time, fluorescent staining results showed that the 17β-estradiol group improved the first polar body (PB1) rate, the cumulus expansion index (CEI), and the mitochondria and endoplasmic reticulum normal distribution rate. G15 is a specific antagonist of GPR30. We found that the 17β-estradiol + G15 groups inhibited the above facilitation. In vitro experiments with porcine oocytes further showed that autophagy was improved by the 17β-estradiol group, and the promotion of 17β-estradiol and the maturation of the oocyte nucleoplasm were impeded by the use of the MEK/ERK-specific inhibitors Trametinib and FR 180204, respectively. Our findings indicated that GPR30 positively regulates the occurrence of autophagy in porcine oocytes and affects oocyte maturation and development via the MEK/ERK signaling pathway. In summary, the study provides a theoretical foundation for the further understanding of the MEK/ERK signaling pathway as a regulatory mechanism for mammalian oocyte maturation.