The cumulus oophorus, also called discus proligerus, is a cluster of cell (called cumulus cells) that surround the oocyte both in the ovarian follicle and after ovulation. In the antral follicle, it may be regarded as an extension of the membrana granulosa. The innermost layer of these cells is the corona radiata.
Functions of the cumulus oophorus include coordination of follicular development and oocyte maturation. Mechanisms of the latter include stimulation of amino acid transport and sterol biosynthesis and regulation of oocyte gene transcription.
It also provides energy substrates for oocyte meiotic resumption and promotes glycolysis.
...regulation of oocyte gene transcription. < In addition, it provides protection for the oocyte. Also used in cloning procedures Cumulus oophorus cells contribute heavily to the maturation and eventual fertilization of an oocyte. As a follicle grows in size and the antrum develops, more layers of cumulus oophorus cells accumulate around the oocyte to aid in the acrosome reaction and sperm penetration into the oocyte. The close proximity between the cumulus oophorus cells and the oocyte favors bidirectional communication, which is vital for oocyte development.
As a part of the process of in vitro fertilization, gene expression profiling of cumulus cells can be performed to estimate oocyte quality and the efficiency of an ovarian hyperstimulation protocol, and may indirectly predict oocyte aneuploidy, embryo development and pregnancy outcomes. Increased knowledge in these aspects is useful in, for example, embryo selection.
In contrast, genes where increased expression is correlated with lower oocyte competence or worse pregnancy outcomes include: BDNF, CCND2, CXCR4, GPX3, HSPB1, DVL3, DHCR7, CTNND1, TRIM28, STAR, AREG, CX43, PTGS2, SCD1 and SCD5.
Biase, Fernando H. & Kimble, Katelyn M. Functional signaling and gene regulatory networks between the oocyte and the surrounding cumulus cells. BMC Genomics. 2018; 19(1):351. doi:10.1186/s12864-018-4738-2.