Dickkopf-related protein 1 is a progestomedin acting on the bovine embryo during the morula-to-blastocyst transition to program trophoblast elongation

Abstract

Progesterone regulates the endometrium to support pregnancy establishment and maintenance. In the ruminant, one action of progesterone early in pregnancy is to alter embryonic development and hasten the process of trophoblast elongation around day 14–15 of pregnancy, which is required for maternal recognition of pregnancy. Here we demonstrate that the WNT antagonist DKK1, whose expression is increased by progesterone treatment, can act on the bovine embryo during day 5 to 7.5 of development (the morula to blastocyst stage) to promote embryonic elongation on day 15 of pregnancy. Embryos were produced in vitro and exposed to 0 or 100 ng/ml recombinant human DKK1 from day 5 to 7.5 of culture. Blastocysts were transferred into synchronized recipient cows on day 7.5 (n = 23 for control and 17 for DKK1). On day 15, cows were slaughtered and embryos recovered by flushing the uterus. Embryo recovery was n = 11 for controls (48% recovery) and n = 11 for DKK1 (65% recovery). Except for two DKK1 embryos, all embryos were filamentous. Treatment with DKK1 increased (P = 0.007) the length of filamentous embryos from 43.9 mm to 117.4 mm and the intrauterine content of the maternal recognition of pregnancy signal IFNT (P = 0.01) from 4.9 µg to 16.6 µg. Determination of differentially expressed genes (DEG), using the R environment, revealed 473 DEG at p < 0.05 but none at FDR < 0.05, suggesting that DKK1 did not strongly modify the embryo transcriptome at the time it was measured. However, samples clustered apart in a multidimensional scaling analyisis. Weighted gene co-expression analysis of the transcriptome of filamentous embryos revealed a subset of genes that were related to embryo length, with identification of a significant module of genes in the DKK1 group only. Thus, several of the differences between DKK1 and control groups in gene expression were due to differences in embryo length. In conclusion, DKK1 can act on the morula-to-blastocyst stage embryo to modify subsequent trophoblast elongation. Higher pregnancy rates associated with transfer of DKK1-treated embryos may be due in part to enhancements of trophoblast growth and antiluteolytic signaling through IFNT secretion. Given that progesterone can regulate both timing of trophoblast elongation and DKK1 expression, DKK1 may be a mediator of progesterone effects on embryonic development.

Application of multi-omics data integration and machine learning approaches to identify epigenetic and transcriptomic differences between in vitro and in vivo produced bovine embryos

“…Thus, inadequate elongation of IVP conceptuses could be a major contributing factor to early embryonic death seen during the peri-implantation period [ 73 ]. Predictions performed in the dataset obtained from the study of Tribulo et al [ 49 ] indicate that treatment of IVP embryos with DKK1 between days 5 and 7.5, just before embryo transfer, could induce epigenomics modifications during the morula to blastocyst transition to regulate subsequent trophoblast elongation. Treatment with DKK1 significantly increased the length of filamentous conceptuses from 43.9 mm to 117.4 mm and the intrauterine content of interferon tau from 4.9 μg/ml to 16.6 μg/ml.…”

“…GSE126680: this dataset corresponds to a study in which IVP embryos were treated or not with 100 ng/ml of recombinant human Dickkopf-related protein 1 (DKK1) from day 5 to 7.5 of culture [ 49 ]. After transfer, conceptuses were recovered at day 15 of gestation and their lengths were measured.…”

Atlas of receptor genes expressed by the bovine morula and corresponding ligand‐related genes expressed by uterine endometrium

“…There was also high expression of the canonical WNT antagonist DKK1 by both the endometrium and embryo. Treatment of bovine embryos with DKK1 can block the inhibitory actions of canonical WNT activators, increase TE formation, trophoblast elongation and competence of embryos to survive to term after transfer into recipients (Denicol et al, 2013(Denicol et al, , 2014Tríbulo et al, 2017Tríbulo et al, , 2019. The most highly expressed receptor for DKK1 in the embryo was CKAP4, which signals through AKT to increase cell proliferation (Kikuchi et al, 2017).…”

The Levels of Serum Periostin on the Day of Frozen-thawed Embryo Transfer Affect the Pregnancy Outcomes

“…Moreover, periostin greatly contributes to cell adhesion, migration, proliferation, and gene regulation, particularly in the development and metastasis of tumors. In tumor metastasis, periostin can enhance the Wnt signaling pathway, which is also involved in the development of the preimplantation embryo and embryo implantation [28,29]. It is also a ligand for ανβ 3 -and ανβ 5integrins to promote cell movement [30].…”