Expression of genes associated with luteolysis in peripheral blood mononuclear cells during early pregnancy in cattle

The conceptus-derived signals that initiate maternal recognition of pregnancy act primarily on the endometrium to inhibit the development of luteolysis, thus modifying the expression of genes in the corpus luteum. The involvement of peripheral blood mononuclear cells (PBMCs) in the formation of this anti-luteolytic mechanism during early pregnancy is uncertain. In this study, PBMCs from non-pregnant and early-pregnant cows were sampled to explore the expression of genes associated with luteolysis, including AKR1B1 (aldo-keto reductase family 1, member B1; a bovine prostaglandin F synthase), PTGFR (PGF2α receptor), OXT (oxytocin), PTGES (PGE synthase), PTGER1 (PGE2 receptor 1), and PGR (progesterone receptor). OXT and PTGFR transcript abundance was low in PBMCs at Day 18 in pregnant individuals. PGR and PTGER1 mRNA abundance was significantly higher at Day 30 in pregnant individuals. AKR1B1 and PTGES transcript abundance was significantly higher at Day 18 in PBMCs from non-pregnant individuals, yet AKR1B1 and PTGES protein abundance was elevated at Day 30 in pregnant individuals-although AKR1B1 dimer may be significantly higher at Day 18 in non-pregnant PBMCs. In conclusion, changes in bovine PBMC gene expression are associated with luteolysis during early pregnancy, which implicate the influence of circulating blood components in controlling luteolysis. Mol. Reprod. Dev. 83: 509-515, 2016. © 2016 Wiley Periodicals, Inc.