Progesterone differentially affects the transcriptomic profiles of cow endometrial cell types

In this study, whole transcriptome changes induced by P4 were analysed by RNAseq following laser capture microdissection (LCM) of endometrial biopsies to isolate LE, GE and ST cells. The study was performed in cows without any sign of uterine disease (as assessed by uterine cytology). At 45 days postpartum, the presence of a Corpus Luteum (CL) assessed by ultrasonography and plasma P4 concentrations were used to categorise healthy cows at 45 days postpartum determine if cows were in luteal phase (CL, P4 concentrations =1 ng/ml; n=4) or not (no CL, P4 concentrations < 1ng/ml; n=9). Overall, endometrial LE, GE, and ST cells shown specific transcriptomic profiles with different proportions and type of genes expressed over 10 tpm. Most of the genes differentially expressed (DEGs) in response to P4 were cell type-specific (93.9%). Genes involved in cell cycle and nuclear division were under-expressed in presence of P4 in GE and LE, highlighting the anti-proliferative action of P4 in epithelial cells. Elevated P4 concentrations were also associated with the under-expression of estrogen receptor 1 (ESR1) in GE and of oxytocin receptor (OXTR) in GE and ST. In ST, transcription factors such as SOX17 and FOXA2 , as well as interferon related genes which are known to regulate uterine epithelial–stromal crosstalk conveying to endometrial receptivity for embryo implantation, were over-expressed under P4. The results from this study show that progesterone regulates endometrial function in a cell type specific way, which looks independent of the expression of its main receptor PGR. These novel insights into uterine physiology, stand the cell compartment, rather than the whole tissue, as a physiological unit. Overall design: High-yielding dairy cows from Holstein herd were submitted to uterine biopsy at 44 ± 0.7 days postpartum (DPP). The uterine status of all the cows included in this study (n = 13) was assessed as healthy, with no clinical signs of endometritis. The cut-off value used to define cows with elevated P4 concentrations was 1 ng/mL. The three endometrial cell types: luminal (LE), glandular (GE) epithelium and stroma (ST) were collected by laser microdissection from endometrial biopsies.