Follicular guidance for oocyte developmental competence.

Satoshi Sugimura,Dulama Richani,Robert B Gilchrist

doi:10.21451/1984-3143-ar2018-0035

Satoshi Sugimura, Dulama Richani + Show 1 more

Open Access

https://doi.org/10.21451/1984-3143-ar2018-0035

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Journal: Animal Reproduction	Publication Date: Jan 1, 2018
Citations: 7	License type: cc-by

Abstract

The advancement of folliculogenesis is coincident with the sequential acquisition of oocyte developmental competence. In practical bovine/porcine ART, cumulus-oocyte complexes (COCs) aspirated from small antral follicles have low developmental competence relative to COCs from medium/large antral follicles, as evidenced by a poor capacity to support embryogenesis up to the blastocyst stage. This is in part because of incomplete differentiation of cumulus cells in small antral follicles, in particular under-developed functionality of EGF signalling. Gonadotrophins and oocyte-secreted paracrine factors cooperate to establish EGF receptor functionality in cumulus cells, which appears to be involved in the acquisition of oocyte developmental competence. Here we review the modification of follicular cumulus cells during antral folliculogenesis involved in oocyte developmental competence.

Highlights

The developmental competence of an oocyte, referring to its capacity to support fertilization, preimplantation embryo and subsequent full-term development, is inherently linked to environmental cues it receives from the follicular somatic cell compartment (Gilchrist and Thompson, 2007)
FSH facilitates the bilateral communication between granulosa cells and between the oocyte and granulosa/cumulus cells (CCs) by promoting gap junctional communication (GJC; El-Hayek and Clarke, 2015), likely via cyclic adenosine
epidermal growth factor (EGF) responsiveness in CCs from small antral follicles cannot be induced by co-culturing with low competence oocytes of small antral follicles, demonstrating that native factors secreted from developmentally competent oocytes mediate this process, and that the oocyte alters its secretome throughout folliculogenesis to regulate CC acquisition of EGF receptor (EGFR) signaling

Summary

Introduction

The developmental competence of an oocyte, referring to its capacity to support fertilization, preimplantation embryo and subsequent full-term development, is inherently linked to environmental cues it receives from the follicular somatic cell compartment (Gilchrist and Thompson, 2007). During the terminal phases of folliculogenesis and oogenesis, FSH promotes expression of the LH and epidermal growth factor (EGF) receptors on granulosa cells (Erickson et al, 1979; El-Hayek et al, 2014). This review will focus on the recent advances in our knowledge of the contribution of endocrine and paracrine cues in the differentiation of follicular granulosa and CCs during antral folliculogenesis, and their contribution to oocyte developmental competence. This knowledge is important for the application of advanced reproductive technologies in domestic animal breeding and in humans. The successful clinical application of the key reproductive technologies of superovulation (combined with artificial insemination or IVF) and oocyte in vitro maturation (IVM) are critically dependent on this knowledge

EGFR signaling and oocyte developmental competence

Conclusion