Table 1.

Cumulus cells-oocyte interactions and their role in the acquisition of oocyte quality

Factor	Signal source	Affected cell type	Function
Gap junctions	Cumulus cells (CCs)	Oocyte	Intercellular channels responsible for small molecules (ions, pyruvate, cyclic nucleotides, metabolites, amino acids, and RNA transcripts) transfer from CCs to the oocyte, which contribute to meiosis, ATP production, and pH balance into the oocyte
KIT pathway	Oocyte	CCs	This pathway induces molecular events that dictate oocyte growth and induces the production of oocyte factors which stimulate granulosa cell proliferation
Growth Differentiation Factor 9 (GDF-9) Bone Morphogenetic Protein 15 (BMP-15)	Oocyte	CCs	Induce expansion, metabolism, differentiation, proliferation, apoptosis, and luteinization of CCs
Enzymatic (e.g., SOD, CAT, GPx) and non-enzymatic (e.g., GSH, VitE, VitC) antioxidant defense	CCs	Oocyte	Metabolize and/or neutralize ROS and protect the oocyte from oxidative stress-induced apoptosis

SOD superoxide dismutase, CAT catalase, GPx glutathione peroxidase, GSH reduced gluthatione, VitE vitamin E, VitC vitamin C