A multiplexed parallel reaction monitoring assay to monitor bovine pregnancy-associated glycoproteins throughout pregnancy and after gestation

PLoS One. 2022 Sep 23;17(9):e0271057. doi: 10.1371/journal.pone.0271057. eCollection 2022.

Abstract

Bovine pregnancy-associated glycoproteins (boPAGs) are extensively glycosylated secretory proteins of trophoblast cells. Roughly 20 different boPAG members are known but their distribution patterns and degree of glycosylation during pregnancy are not well characterized. The objective of the present study was the development of a parallel reaction monitoring-based assay for the profiling of different boPAGs during pregnancy and after gestation. Furthermore, we investigated the effects of N-glycosylation on our analytical results. BoPAGs were purified from cotyledons of four different pregnancy stages. The assay detects 25 proteotypic peptides from 18 boPAGs in a single run. The highest abundances were found for boPAG 1 in both, glycosylated and deglycosylated samples. Strongest effects of glycosylation were detected during mid and late pregnancy as well as in afterbirth samples. Furthermore, we identified different boPAG-clusters based on the observed relative protein abundances between glycosylated and deglycosylated samples. A linkage between the impact of glycosylation and potential N-glycosylation sites or phylogenetic relation was not detected. In conclusion, the newly developed parallel reaction monitoring-based assay enables for the first time a comprehensive semi-quantitative profiling of 18 different boPAGs during pregnancy and post-partum on protein level, thereby investigating the influence of glycosylation. The results of this study provide new and important starting points to address further research on boPAGs to better understand their physiological role during pregnancy and for the development of new pregnancy detection tests.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Female
  • Glycoproteins* / metabolism
  • Glycosylation
  • Phylogeny
  • Placenta* / metabolism
  • Pregnancy
  • Trophoblasts / metabolism

Substances

  • Glycoproteins

Grants and funding

“This work was supported by the H. Wilhelm Schaumann Stiftung, Hamburg, Germany (https://www.schaumann-stiftung.de/; received TK) and the Landwirtschaftliche Rentenbank, Frankfurt am Main, Germany [grant number 785745] (https://www.rentenbank.de/; received TK, JT). Furthermore, the authors acknowledge support by the Open Access Publication Funds of the University of Goettingen. The H. Wilhelm Schaumann Stiftung provided support in form of salaries for the author TK. The Landwirtschaftliche Rentenbank provided support in the form of salaries for authors [TK] and research material [TK, JT]. The Open Access Publication Funds of the University of Goettingen only cover the publication costs. The funders of the study did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the "author contributions’" section. There was no additional external funding received for this study.”