AUTHOR=Liu Huage , Zhou Dan , Liu Cong , Zhuan Qingrui , Luo Yan , Mo Xianhong , Fu Xiangwei , Hou Yunpeng 

TITLE=The Calcium-Sensing Receptor Is Involved in Follicle-Stimulating Hormone-Induced Cumulus Expansion in in vitro Cultured Porcine Cumulus-Oocyte Complexes

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2021.625036

DOI=10.3389/fcell.2021.625036

ISSN=2296-634X

ABSTRACT=<p>The Calcium-Sensing Receptor (CASR) is a G protein-coupled receptor of the C family that reportedly promotes maturation of porcine oocytes. However, its role in cumulus expansion of cumulus-oocyte complexes (COCs) is not well known. This study was conducted to determine the role of CASR and potential mechanisms involved during <italic>in vitro</italic> maturation (IVM) of porcine COCs. After culture of COCs in follicle-stimulating hormone (FSH)-supplement maturation medium for 24 h, the time of breakdown of the germinal vesicle (GVBD), indicative of initiation of meiotic maturation, resulted in an increased (<italic>p</italic> &lt; 0.05) <italic>CASR</italic> mRNA expression level in cumulus cells. Moreover, IVM of COCs in 10 μM of the CASR agonist NPS R-568 promoted (<italic>p</italic> &lt; 0.05) cumulus expansion but only in FSH-containing medium. Conversely, 20 μM of the CASR inhibitor NPS2390 precluded cumulus expansion. We next tested the effect of the CASR agonist/inhibitor on the expression of cumulus expansion-related genes. The CASR agonist significantly upregulated the expression of hyaluronan acid synthase 2 (<italic>HAS2</italic>), whereas the CASR inhibitor downregulated the expression of all <italic>HAS2</italic>, prostaglandin-endoperoxide synthase 2 (<italic>PTGS2</italic>), and tumor necrosis factor a-induced protein 6 (<italic>TNFAIP6</italic>). Altogether, these results suggest that CASR activity is involved in FSH-stimulated porcine cumulus expansion.</p>