@phdthesis{01JKBWEP8NGT0RECSAKAQKSTWY,
  abstract     = {{Infertility is a global health issue affecting one in seven couples, causing significant emotional and financial burdens. The World Health Organization recognizes it as a major public health concern, driven by various factors that impair gamete functionality. In the livestock industry, particularly in dairy cattle, infertility affects 15–20% of animals, leading to substantial economic losses.
Assisted reproductive technologies (ART) have made significant advancements in both humans and livestock. Globally, more than six million babies have been born thanks to ART, and over one million bovine embryos are transferred annually. However, challenges remain, particularly concerning oocyte quality. This dissertation focuses on investigating the interaction between cumulus cells and oocytes during bovine oocyte maturation, with a specific emphasis on the role of microRNAs (miRNAs) and gap junctions. These findings could contribute to improving ART applications for both humans and livestock.
The research demonstrated that miRNAs are transferred via gap junctions within the cumulus-oocyte complex (COC). One example is bta-miR-21-5p, a key regulator of cumulus cell viability and oocyte maturation. The transfer of this miRNA through gap junctions was confirmed using sequencing and visualization techniques, providing the first direct evidence of miRNA-mediated communication within the COC. Additionally, an in-depth analysis of the miRNA landscape revealed novel miRNAs, including bta-novel-miR-589 and bta-novel-miR-906. These miRNAs regulate critical processes such as cell cycle progression and apoptosis, influencing oocyte quality and the success of embryonic development.
Moreover, the research demonstrated that bta-novel-miR-589 has a direct impact on cumulus cell expansion and embryo quality. Adding this miRNA to the maturation medium enhanced cumulus expansion, reduced apoptosis, and increased cleavage and blastocyst rates, while inhibition of this miRNA had the opposite effects. These findings highlight the potential of miRNAs, such as bta-novel-miR-589, to improve reproductive outcomes, offering promising prospects for optimizing ART in both human and veterinary contexts.}},
  author       = {{Six, Rani}},
  language     = {{eng}},
  pages        = {{X, 220}},
  publisher    = {{Ghent University. Faculty of Veterinary Medicine}},
  school       = {{Ghent University}},
  title        = {{MicroRNA function during maturation and their gap-junctional transfer in the bovine cumulus-oocyte complex}},
  year         = {{2025}},
}