Estradiol concentration at estrus is associated with the uterine luminal transcriptome in the subsequent luteal phase in beef cows

The uterine environment influences early embryonic development, affecting the establishment of pregnancy. Estradiol is one of the main modulators of uterine functions, affecting uterine receptivity to the embryo. Therefore, our objective was to compare the post-estrus uterine luminal epithelial transcriptome of cross-bred beef cows that displayed estrus and ovulated spontaneously but had a wide range in the concentration of estradiol at estrus. Forty cross-bred beef cows received a CIDR and GnRH injection on d -9 and a CIDR removal followed by a PGF 2α injection on d -2. The manifestation of estrus behavior (d 0) was observed twice daily after PGF 2α , followed by ovarian ultrasonography and blood collection for E2. On days 4, 7, and 14, ovarian ultrasonography and blood collections were performed for E2 and P4, and luminal epithelial cells were harvested for RNAseq. The concentrations of estradiol at estrus ranged from 1.14 to 7.62 pg/mL and averaged 4.14 ± 0.62 pg/mL. Overall, the greater concentration of estradiol was negatively associated with genes related to cell proliferation and positively associated with genes involved in cell differentiation on day 4, negatively associated with transcription and translation-related processes and positively associated with pathways involved in the modulation of Toll-like receptor cascades and in cytokines responsible for regulating immune responses on day 7, and negatively associated with integrin-linked kinase signaling on day 14 (Benjamini–Hochberg adjusted P-value ≤ 0.05). In summary, the concentration of estradiol at estrus is associated with a long-lasting alteration in gene expression of uterine luminal epithelial cells despite all cows displaying estrus and having spontaneous ovulation.