Preliminary functional inquiry of lncRNA ENST00000433673 in embryo implantation using bioinformatics analysis

Long non-coding RNAs (lncRNAs), a class of non-coding RNA, have been shown to be essential in many diseases, such as infertility. Here, we found three candidate lncRNAs, ENST00000414116, ENST00000433673, and ENST00000448179, that are highly expressed in the uterus endometrial tissues of normal patients compared to the tissues of patients with adenomyosis, endometriosis, and recurrent implantation failure. lncRNAs ENST00000414116 and ENST00000433673 showed high expression in endometrial stromal cells (ESCs) and endometrial epithelial cells (EECs), respectively, and lncRNA ENST00000448179 was specifically expressed in ESCs. The bioinformatics analysis results indicated that the target mRNAs of lncRNA ENST00000433673 were related to biological adhesion. Interestingly, intercellular adhesion molecule 1 (ICAM1), an interacting mRNA of the target mRNA integrin subunit alpha L (ITGAL), has been reported be an important regulator of embryo implantation. Further studies found that the target mRNA ITGAL and the interacting mRNA ICAM1 were highly expressed in the uterus endometrial tissues and EECs of normal patients. Based on our results, our study indicates that lncRNA ENST00000433673 might mediate the high expression of the target mRNA ITGAL, thereby promoting the expression of the interacting mRNA ICAM1 and the adhesion of EECs, which facilitates adhesion and implantation between the embryo and the mater. Abbreviations: AMs: adenomyosis; EMs: endometriosis; RIF: recurrent implantation failure; miRNAs: microRNAs; lncRNAs: Long non-coding RNAs; RT-qPCR: real-time quantitative PCR; ESCs: endometrial stromal cells; EECs: endometrial epithelial cells; BFE: free binding energy; PCDHB9: protocadherin beta 9; PARVG: parvin gamma; MAPK6: mitogen-activated protein kinase 6; LAF1: lymphocyte function-associated antigen 1.