The microenvironment of a preimplantation embryo can influence changes in development that affect postnatal phenotypes. One of the potential mediators of this effect in many species is colony-stimulating factor (CSF2), which can increase an embryo's ability to establish pregnancy after its transfer into recipients. Exposure of embryos to CSF2 during early development can also affect the pattern of development later in pregnancy in a sex-dependent manner. We therefore hypothesized that treatment of in vitro-produced embryos with CSF2 in culture would alter birth weight and postnatal growth of the resultant calf. Body weight and withers height were measured for Holstein heifer calves produced in vitro with or without 10 ng/ml CSF2 and for calves produced by artificial insemination. There were no differences in birth weight between groups; thereafter, however, calves from the CSF2-treated group experienced greater increases in body weight through 13 months of age, with only small differences in withers height. These results support the model that an embryo's postnatal characteristics can be programmed during the preimplantation period, and that CSF2 is one of the embryokines through which programming is directed. Mol. Reprod. Dev. 82: 892-897, 2015. © 2015 Wiley Periodicals, Inc.

The reproductive tract secretes bioactive molecules collectively known as embryokines that can regulate embryonic growth and development. In the present study we tested four growth factors expressed in the endometrium for their ability to modify the development of the bovine embryo to the blastocyst stage and alter the expression of genes found to be upregulated (bone morphogenetic protein 15 (BMP15) and keratin 8, type II (KRT8)) or downregulated (NADH dehydrogenase 1 (ND1) and S100 calcium binding protein A10 (S100A10)) in embryos competent to develop to term. Zygotes were treated at Day 5 with 0.01, 0.1 or 1.0nM growth factor. The highest concentration of activin A increased the percentage of putative zygotes that developed to the blastocyst stage. Connective tissue growth factor (CTGF) increased the number of cells in the inner cell mass (ICM), decreased the trophectoderm:ICM ratio and increased blastocyst expression of KRT8 and ND1. The lowest concentration of hepatocyte growth factor (HGF) reduced the percentage of putative zygotes becoming blastocysts. Teratocarcinoma-derived growth factor 1 increased total cell number at 0.01nM and expression of S100A10 at 1.0nM, but otherwise had no effects. Results confirm the prodevelopmental actions of activin A and indicate that CTGF may also function as an embryokine by regulating the number of ICM cells in the blastocyst and altering gene expression. Low concentrations of HGF were inhibitory to development.

Colony-stimulating factor 2 (CSF2) is an embryokine that improves competence of the embryo to establish pregnancy and which may participate in developmental programming. We tested whether culture of bovine embryos with CSF2 alters fetal development and alleviates abnormalities associated with in vitro production (IVP) of embryos. Pregnancies were established by artificial insemination (AI), transfer of an IVP embryo (IVP), or transfer of an IVP embryo treated with 10 ng/ml CSF2 from day 5 to 7 of development (CSF2). Pregnancies were produced using X-sorted semen. Female singleton conceptuses were collected on day 86 of gestation. There were few morphological differences between groups, although IVP and CSF2 fetuses were heavier than AI fetuses. Bicarbonate concentration in allantoic fluid was lower for IVP than for AI or CSF2. Expression of 92 genes in liver, placenta, and muscle was determined. The general pattern for liver and placenta was for IVP to alter expression and for CSF2 to sometimes reverse this effect. For muscle, CSF2 affected gene expression but did not generally reverse effects of IVP. Levels of methylation for each of the three tissues at 12 loci in the promoter of insulin-like growth factor 2 (IGF2) and five in the promoter of growth factor receptor bound protein 10 were unaffected by treatment except for CSF2 effects on two CpG for IGF2 in placenta and muscle. In conclusion, CSF2 can act as a developmental programming agent but alone is not able to abolish the adverse effects of IVP on fetal characteristics.

BackgroundColony stimulating factor 2 can have multiple effects on the function of the preimplantation embryo that include increased potential to develop to the blastocyst stage, reduced apoptosis, and enhanced ability of inner cell mass (ICM) to remain pluripotent after culture. The objective of the current experiment was to identify genes regulated by CSF2 in the ICM and trophectoderm (TE) of the bovine blastocyst with the goal of identifying possible molecular pathways by which CSF2 increases developmental competence for survival. Embryos were produced in vitro and cultured from Day 6 to 8 in serum-free medium containing 10 ng/ml recombinant bovine CSF2 or vehicle. Blastocysts were harvested at Day 8 and ICM separated from TE by magnetic-activated cell sorting. RNA was purified and used to prepare amplified cDNA, which was then subjected to high-throughput sequencing using the SOLiD 4.0 system. Three pools of amplified cDNA were analyzed per treatment.ResultsThe number of genes whose expression was regulated by CSF2, using P < 0.05 and >1.5-fold difference as cut-offs, was 945 in the ICM (242 upregulated by CSF2 and 703 downregulated) and 886 in the TE (401 upregulated by CSF2 and 485 downregulated). Only 49 genes were regulated in a similar manner by CSF2 in both cell types. The three significant annotation clusters in which genes regulated by ICM were overrepresented were related to membrane signaling. Genes downregulated by CSF2 in ICM were overrepresented in several pathways including those for ERK and AKT signaling. The only significant annotation cluster containing an overrepresentation of genes regulated by CSF2 in TE was for secreted or extracellular proteins. In addition, genes downregulated in TE were overrepresented in TGFβ and Nanog pathways.ConclusionsDifferentiation of the blastocyst is such that, by Day 8 after fertilization, the ICM and TE respond differently to CSF2. Analysis of the genes regulated by CSF2 in ICM and TE are suggestive that CSF2 reinforces developmental fate and function of both cell lineages.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-016-2038-y) contains supplementary material, which is available to authorized users.

Plasma lipoproteins play critical roles in energy metabolism and inflammation. Concentrations of high-density lipoproteins (HDL) are linked to reproductive outcomes and milk yields in dairy cattle. Low-density lipoproteins (LDL), which are enzymatically formed in the blood from very low-density lipoproteins (VLDL) following secretion by the liver, have been used as a surrogate marker of liver function due to the rapid influx of circulating VLDL into the lactating mammary gland. In humans, the composition of plasma lipoproteins is reflected in lipoprotein particle size distribution, and both of these parameters are highly predictive of disease development and related health outcomes. Bovine HDL are overall larger, less dense particles compared to human HDL. Lipoprotein particle size distribution in both health and disease is understudied in the bovine. We hypothesize that a more detailed analysis of lipoproteins could hold diagnostic and/or prognostic value in the study of dairy cattle health and production. In this study, we took the first steps in this characterization and used a high-resolution polyacrylamide gel electrophoretic assay to better define LDL and HDL at the subfraction level in Holstein cows at different stages of lactation. We extensively characterized the lipoprotein particle size distribution in healthy lactating dairy cattle. We identified subfractions of LDL that were prominent only in the dry period and subfractions of HDL that were highest in cows during mid-lactation. Use of this method could be informative in the study of multiple herds and management strategies, including longitudinal evaluation of animals and production parameters.