The bovine cumulus proteome is influenced by maturation condition and maturational competence of the oocyte

Abstract

In vitro maturation (IVM) of oocytes has still a negative impact on the developmental competence of oocytes. Therefore, this study analysed the cumulus proteome of individual cumulus-oocyte complexes (COCs) with and without maturational competence, matured under in vivo or in vitro conditions (n = 5 per group). A novel, ultrasensitive mass spectrometry (MS) based protein profiling approach, using label-free quantification, was applied. The detected cumulus proteome included 2226 quantifiable proteins and was highly influenced by the maturation condition (479 differentially expressed proteins) as well as maturational competence of the corresponding oocyte (424 differentially expressed proteins). Enrichment analysis showed an overrepresentation of the complement and coagulation cascades (CCC), ECM-receptor interaction and steroid biosynthesis in cumulus of COCs that matured successfully under in vivo conditions. Verification of the origin of CCC proteins was achieved through detection of C3 secretion into the maturation medium, with significantly increasing concentrations from 12 (48.4 ng/ ml) to 24 hours (68 ng/ml: p < 0.001). In relation, concentrations in follicular fluid, reflecting the in vivo situation, were >100x higher. In summary, this study identified important pathways that are impaired in IVM cumulus, as well as potential markers of the maturational competence of oocytes.

Oocyte Selection for In Vitro Embryo Production in Bovine Species: Noninvasive Approaches for New Challenges of Oocyte Competence

“…Nonetheless, the few studies described many proteins involved in cell signaling that may have a role in cumulus-oocyte communication and competence. Most of the proteins are involved in components of integrin, actin cytoskeleton, mitogen-activated protein kinases (MAPK) and phosphatidylinositol 3-kinase (PI3K) signaling pathways, extracellular matrix (ECM) receptor interactions, steroid biosynthesis, and glucose and carbohydrate metabolism, which may have implications in various reproductive processes such as oocyte development and maturation [156][157][158] (Table 2). A recent study reported a highly sensitive approach to characterize the CC proteome from a single COC after in vivo or in vitro maturation [156].…”

Protein Cargo of Extracellular Vesicles From Bovine Follicular Fluid and Analysis of Their Origin From Different Ovarian Cells

“…The findings of the present study enhance our knowledge of bovine ffEV protein cargo. Indeed, until now, EV-proteomic studies in bovine have been limited to exosomes derived from milk ( 44 ) plasma, saliva, urine ( 27 , 28 ), oviduct fluid ( 10 ), and spent medium containing ovarian cell secretions ( 45 ). Here, we identified 322 proteins in ffEVs.…”

“…This characteristic of ffEVs makes them a valuable source of novel diagnostic and therapeutic strategies in reproductive medicine ( 74 ). Although their utility is theoretical currently, data have shown that levels of cumulus proteins were different in mature and non-mature COCs ( 45 ). These differential proteins were detected in ffEVs, and therefore, ffEVs may be involved in the acquisition of competence by the enclosed oocyte.…”

Oocyte Selection for <em>in vitro</em> embryo Production in Bovine Species: Non-Invasive Approaches for the New Challenges of Oocyte Competence

“…Nonetheless, the few studies have described many proteins involved in the cell signaling that may have a role in cumulus-oocyte communication and competence. Most of the proteins involved are components of integrin, actin cytoskeleton, MAPK and PI3K signaling pathways, ECM-receptor interactions, steroid biosynthesis, glucose and carbohydrate metabolism, that may have implications in various reproductive processes such as oocyte development, and maturation [154,155] (Table 2). A recent study reports a highly sensitive approach to characterize the CC proteome from a single COC after in vivo or in vitro maturation [154].…”

“…Most of the proteins involved are components of integrin, actin cytoskeleton, MAPK and PI3K signaling pathways, ECM-receptor interactions, steroid biosynthesis, glucose and carbohydrate metabolism, that may have implications in various reproductive processes such as oocyte development, and maturation [154,155] (Table 2). A recent study reports a highly sensitive approach to characterize the CC proteome from a single COC after in vivo or in vitro maturation [154]. This method shows the potential to directly connect the cumulus proteome to the developmental potential of the corresponding oocyte, as already performed at gene expression level.…”