Cumulus cell gene expression as a marker of oocyte quality

Abstract

Cumulus cells (CCs) are a highly specialized cell type that surround the mammalian oocyte from antrum formation to the early stages of embryo development in the oviduct. During this period of close vicinity, CCs maintain paracrine and cell-to-cell communications with the oocyte. The increasing use of CCs to predict oocyte quality requires a growing understanding of their involvement in oocyte developmental competence acquisition. This chapter highlights the current knowledge about CC differentiation and communications with the oocyte. Special focus is given to the molecular biomarkers differentially expressed in CCs that reflect higher oocyte quality and therefore are associated with successful embryo development and/or implantation. The biological, signaling, and molecular functions and/or pathways of CCs during oocyte maturation, ovulation, fertilization, and early embryo development are also discussed. Using recent findings in other tissues/species, some hypotheses about the processes whereby CCs exert their functions are suggested. Further characterization will be required to refine these biomarkers in order to improve both animal and human ART.