Identification of 56 Proteins Involved in Embryo–Maternal Interactions in the Bovine Oviduct

Abstract

The bovine embryo develops in contact with the oviductal fluid (OF) during the first 4–5 days of pregnancy. The aim of this study was to decipher the protein interactions occurring between the developing embryo and surrounding OF. In-vitro produced 4–6 cell and morula embryos were incubated or not (controls) in post-ovulatory OF (OF-treated embryos) and proteins were then analyzed and quantified by high resolution mass spectrometry (MS) in both embryo groups and in OF. A comparative analysis of MS data allowed the identification and quantification of 56 embryo-interacting proteins originated from the OF, including oviductin (OVGP1) and several annexins (ANXA1, ANXA2, ANXA4) as the most abundant ones. Some embryo-interacting proteins were developmental stage-specific, showing a modulating role of the embryo in protein interactions. Three interacting proteins (OVGP1, ANXA1 and PYGL) were immunolocalized in the perivitelline space and in blastomeres, showing that OF proteins were able to cross the zona pellucida and be taken up by the embryo. Interacting proteins were involved in a wide range of functions, among which metabolism and cellular processes were predominant. This study identified for the first time a high number of oviductal embryo-interacting proteins, paving the way for further targeted studies of proteins potentially involved in the establishment of pregnancy in cattle.

A Comparative View on the Oviductal Environment during the Periconception Period

“…In addition, annexin A1 (ANXA1) is a protein which has been recently identified as an embryo-interacting maternal protein from bovine OF by Banliat, and collaborators in 2020 [ 98 ], and has also been immunodetected within the perivitelline space and inside.…”

“…It was also found bound to the ZP in 9-day old bovine embryos, but only if the in vitro culture medium contained OVGP1 until day 3.5 post-insemination [ 201 ]. Using OF during the incubation of in vitro-produced bovine embryos, OVGP1 was localized in the perivitelline space and in blastomeres of both 4–6 cell and morula-stage embryos, but not bound to the ZP [ 98 ]. This agrees with the previously described reversible nature of OVGP1-ZP binding [ 200 ], whereby only two bovine OVGP1 proteins of 75 and 95 kDa were reported to bind porcine ZP [ 200 ].…”

Embryo–Maternal Interactions Underlying Reproduction in Mammals

“…Bridi et al give special emphasis on the role of EVs (oviductal EVs and uterine EVs) in the modulation of embryo–maternal interactions during early pregnancy [ 7 ]. The study of Banliat et al [ 11 ] specifically identified a high number of proteins of the bovine oviductal fluid that interact with the early embryo, i.e., 4–8 cell and morula embryos. Changes in the composition of the bovine oviductal fluid isolated from the ampulla and the isthmus were analyzed during the estrous cycle and pregnancy stage in the study by Rodríguez-Alonso et al [ 12 ].…”

Serine 165 phosphorylation of SHARPIN regulates the activation of NF-κB

“…Peptide extracts were evaporated and afterward reconstituted in 0.1% formic acid. Peptide extracts were analyzed by liquid nanochromatography (nanoLC) nanoElute coupled with a TimsTOF Pro mass spectrometer (Bruker)(Banliat et al, 2020). Generated peaks were analyzed with the Mascot database search engine (MatrixScience version 2.5.01) for peptide and protein identification.…”