Methionine in bovine uterine luminal fluid during early pregnancy — ASN Events
  1. Schedule
  2. Joint Poster Session
  3. Methionine in bovine uterine luminal fluid during early pregnancy

Methionine in bovine uterine luminal fluid during early pregnancy (#506)

Soraya Campbell 1 , Danna de Sagun 1 , Margot Day 1 , Laura Lindsay 1
  1. University of Sydney, Sydney, NSW, Australia

Background

Uterine luminal fluid (ULF) surrounds the developing bovine blastocyst in the uterine cavity and is composed of factors that are needed for successful implantation. The composition of ULF changes significantly throughout pregnancy especially during maternal recognition of pregnancy which is initiated by embryo-derived interferon-tau (IFN-τ). The mechanism by which IFN-τ modulates ULF composition including amino acids (AAs) remains unknown. 

Methods and Results

Using an in vitro culture system, bovine uterine epithelial cells (BUECs) were cultured with 100nM IFN-τ for 1 hour and culture media was analysed using mass spectrometry for common amino acids. Methionine concentration was significantly increased (p<0.05) in IFN-τ treated cells, with no other essential amino acids showing significant changes.

Methionine, a key methyl-donor for epigenetic regulation, may influence gene activation during early development of the bovine blastocyst. To assess its role in blastocyst development, day 10 bovine blastocysts were cultured to day 14 in media containing 0-150µM methionine. At day 12 blastocysts cultured with no methionine were significantly smaller than those cultured with methionine. At day 14 all blastocysts cultured with no methionine underwent embryo degeneration whilst those exposed to methionine were mainly still alive, suggesting that methionine is essential for development of the bovine blastocyst. In future experiments immunofluorescence microscopy will be used to evaluate methionine-dependent effects on inner cell mass differentiation into epiblasts and hypoblasts.

Conclusion

Evidence from other species has found that methionine may regulate receptivity through the release of blastocyst derived secretions(1). Future experiments will focus on the potential link between the blastocyst secretions released in response to methionine and upregulation of receptivity adhesion molecules in BUECs. Methionine may play a key role in improving uterine receptivity and blastocyst competence both of which are required for successful implantation and pregnancy.

 

 

  1. Cai, S., Xue, B., Li, S., Wang, X., Zeng, X., Zhu, Z., Fan, X., Zou, Y., Yu, H., Qiao, S., & Zeng, X. (2025). Methionine regulates maternal-fetal immune tolerance and endometrial receptivity by enhancing embryonic IL-5 secretion. Cell Rep, 44(2), 115291. https://doi.org/10.1016/j.celrep.2025.115291