The Interaction of lncRNA XLOC-2222497, AKR1C1, and Progesterone in Porcine Endometrium and Pregnancy

Abstract

The endometrium is an important tissue for pregnancy and plays an important role in reproduction. In this study, high-throughput transcriptome sequencing was performed in endometrium samples of Meishan and Yorkshire pigs on days 18 and 32 of pregnancy. Aldo-keto reductase family 1 member C1 (<i>AKR1C1</i>) was found to be a differentially expressed gene, and was identified by quantitative real-time PCR (qRT-PCR) and Western blot. Immunohistochemistry results revealed the cellular localization of the AKR1C1 protein in the endometrium. Luciferase activity assay demonstrated that the <i>AKR1C1</i> core promoter region was located in the region from -706 to -564, containing two nuclear factor erythroid 2-related factor 2 (NRF2) binding sites (antioxidant response elements, AREs). <i>XLOC-2222497</i> was identified as a nuclear long non-coding RNA (lncRNA) highly expressed in the endometrium. <i>XLOC-2222497</i> overexpression and knockdown have an effect on the expression of <i>AKR1C1</i>. Endocrinologic measurement showed the difference in progesterone levels between Meishan and Yorkshire pigs. Progesterone treatment upregulated <i>AKR1C1</i> and <i>XLOC-2222497</i> expression in porcine endometrial epithelial cells. In conclusion, transcriptome analysis revealed differentially expressed transcripts during the early pregnancy process. Further experiments demonstrated the interaction of XLOC-2222497/AKR1C1/progesterone in the endometrium and provided new potential targets for pregnancy maintenance and its control.