The transcriptome of follicular cells: biological insights and clinical implications for the treatment of infertility
Authors: Elpida Fragouli, Maria D. Lalioti, Dagan Wells
Journal: Human Reproduction Update (2013)

† Transcriptomic analysis of follicular cells: methodological strategies for global and specific gene expression assessment † Gene expression, aneuploidy and advancing female age † Transcriptomic analysis of follicular cells associated with oocytes at various maturational stages † Disturbances of cumulus cell gene expression induced by controlled ovarian stimulation † Transcriptomic analysis of follicular cells: clinical implications † Conclusion: the development and clinical application of non-invasive assays to assess oocytes and select embryos background: Oocyte maturation is under strict regulatory control, not only from intrinsic cellular processes, but also extrinsic influences.While the oocyte is directly connected to the surrounding cumulus cells (CCs) via a network of gap junctions facilitating communication and exchange of molecules, it is also influenced by the greater follicular environment.In order to produce an oocyte capable of successfully transmitting the female genetic material and able to support the earliest stages of preimplantation development, cytoplasmic and nuclear maturation must be achieved.Granulosa and CCs play an essential role in the maturation and competence acquisition of the developing oocyte.The fact that these cells are closely associated with the oocyte, share the same microenvironment and can be easily collected during IVF procedures makes them attractive targets for basic research and the development of clinically relevant assays.Analysis of follicular cells is likely to reveal important information concerning the viability and genetic constitution of their associated oocyte, as well as increase our understanding of normal follicular processes and the impact of disorders or of medical interventions such as controlled ovarian stimulation (COS).This review summarizes results obtained during the investigation of granulosa and CCs, and considers the possibilities of using follicular cells as surrogate markers of stimulation response during IVF, oocyte/embryo competence and clinical outcome.methods: In order to summarize the current knowledge obtained from the analysis of follicular cells, a thorough literature search was carried out.Relevant research articles published in English up to March 2013 were reviewed.results: Multiple groups of genes expressed in follicular cells have been identified as possible indicators of ovulation, oocyte maturity, fertilization, chromosome status, ability to generate embryos capable of reaching the blastocyst stage of development, embryo morphology and the establishment of a pregnancy.However, there is a general lack of uniformity concerning groups of gene biomarkers among different studies.conclusions: Extensive investigation of genes and proteins of granulosa and CCs has provided a detailed insight into the follicular microenvironment surrounding oocytes.It was evident from the data reviewed that the gene expression of follicular cells influences and is influenced by the