DNA Methylation Changes in Endometrium and Correlation with Gene Expression During Ovarian Hyper-stimulation

Abstract

Persistent supraphysiological serum estradiol (E2) levels during controlled ovarian hyper-stimulation (COH) have a detrimental effect on endometrial receptivity. In this study, we explored RNA expression and DNA methylation profiles from patients’ endometrium. The patients were divided into two groups: the COH cycle (n=3, hCG+7) group and normal cycle group (n=3, LH+5). Quantitative RT-PCR was used to validate the expression of selected differentially expressed genes (DEGs). Comparing natural and stimulated endometrium transcriptome profiles revealed 640 DEGs, with a > 2-fold change (FC) and p < 0.01. The DEGs were reported to be involved in endometrial receptivity and epithelial-mesenchymal transition (EMT). The expression of IGFBP-1, MMP9, FGF9, LIF, WNT4, HAND2, and immune system-related genes were significantly up-regulated. By clustering and KEGG pathway analysis, molecules and pathways associated with endometrial receptivity (PI3K-Akt signaling pathway) were identified. DNA methylation was partially correlated to gene expression. In conclusion, RNA-seq COH affected endometrial receptivity and EMT/MET process by accelerated the decidualization process and broken the balance of estrogen and progesterone receptors expression. However, this was not associated with changes in DNA methylation.