Failure to launch: aberrant cumulus gene expression during oocyte in vitro maturation

22 November 2016:

Failure to launch: aberrant cumulus gene expression during oocyte in vitro maturation

http://m.reproduction-online.org/content/153/3/R109.abstract
Hannah M Brown, Kylie R Dunning, Melanie Sutton-McDowall, Robert B Gilchrist,
Jeremy G Thompson and Darryl L Russell

Abstract
In vitro maturation (IVM) offers significant benefits for human infertility treatment and animal breeding, but this potential is yet to be
fully realised due to reduced oocyte developmental competence in comparison with in vivo matured oocytes. Cumulus cells occupy
an essential position in determining oocyte developmental competence. Here we have examined the areas of deficient gene
expression, as determined within microarrays primarily from cumulus cells of mouse COCs, but also other species, between in vivo
matured and in vitro matured oocytes. By retrospectively analysing the literature, directed by focussing on downregulated genes, we
provide an insight as to why the in vitro cumulus cells fail to support full oocyte potential and dissect molecular pathways that have
important roles in oocyte competence. We conclude that the roles of epidermal growth factor signalling, the expanded extracellular
matrix, cumulus cell metabolism and the immune system are critical deficiencies in cumulus cells of IVM COCs.