Transcriptomic profile of genes encoding proteins responsible for regulation of cells differentiation and neurogenesis in vivo and in vitro – an oocyte model approach

The growth and development of the oocyte is essential for the ovarian follicle. Cumulus cells (CCs) - a population of granulosa cells - exchange metabolites, proteins and oocyte-derived paracrine factors with the oocyte through gap junctions, to contribute to the competency and health of the oocyte. This bi-directional communication of the cumulus-oocyte complex could be better understood through the micro-analysis of a porcine oocyte gene expression before in vitro maturation (IVM) and after. Additionally, the study of the somatic and gamete cells differentiation capability into neuronal lineage would be promising for future stem cell research as granulosa cells are easily accessible waste material from in vitro fertilization (IVF) procedures. Therefore, in this study, the oocytes of 45 pubertal Landrace gilts were isolated and the protein expression of the COCs were analyzed through micro-analysis techniques. Genes belonging to two ontological groups: neuron differentiation and negative regulation of cell differentiation have been identified which have roles in proliferation, migration and differentiation. Twenty identified porcine oocyte genes (VEGFA, BTG2, MCOLN3, EGR2, TGFBR3, GJA1, FST, CTNNA2, RTN4, MDGA1, KIT, RYK, NOTCH2, RORA, SMAD4, ITGB1, SEMA5A, SMARCA1, WWTR1 and APP) were found to be down-regulated after the transition of IVM compared to in vitro. These results could be applied as gene markers for the proliferation, migration and differentiation occurring in the bi-directional communication between the oocyte and CCs.

Running title: Differentiation and neurogenesis in oocyte cells