Comprehensive RNA sequencing of healthy human endometrium at two time points of the menstrual cycle.

Endometrial receptivity is crucial for implantation and establishment of a normal pregnancy. The shift from proliferative to receptive endometrium is still far from being understood. In this paper, we comprehensively present the transcriptome of the human endometrium by comparing endometrial biopsies from proliferative phase with consecutive biopsies 7-9 days after ovulation. The results show a clear difference in expression between the two time points using both total and small RNA sequencing. A total of 3,297 messenger RNAs (mRNAs), 516 long noncoding RNAs (lncRNAs), and 102 small noncoding RNAs were identified as statistically differentially expressed between the two time points. We show a thorough description of the change in mRNA between the two time points and display lncRNAs, small nucleolar RNAs, and small nuclear RNAs not previously reported in the healthy human endometrium. In conclusion, this paper reports in detail the shift in RNA expression from the proliferative to receptive endometrium.