ACE inhibitors on ACE1, ACE2, and TMPRSS2 expression and spheroid attachment on human endometrial Ishikawa cells.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters cells via receptor angiotensin-converting enzyme 2 (ACE2) and co-receptor transmembrane serine protease 2 (TMPRSS2). However, patients with SARS-CoV-2 infection receiving ACE1 inhibitors had higher ACE2 expression and were prone to poorer prognostic outcomes. Until now, information on the expression of ACE1, ACE2, and TMPRSS2 in human endometrial tissues, and the effects of ACE inhibitors on embryo implantation are limited.

Expression of membrane protein disulphide isomerase A1 (PDIA1) disrupt a reducing microenvironment in endometrial epithelium for embryo implantation.

Various proteins in the endometrial epithelium are differentially expressed in the receptive phase and play a pivotal role in embryo implantation. The Protein Disulphide Isomerase (PDI) family contains 21 members that function as chaperone proteins through their redox activities. Although total PDIA1 protein expression was high in four common receptive (Ishikawa and RL95-2) and non-receptive (HEC1-B and AN3CA) endometrial epithelial cell lines, significantly higher membrane PDIA1 expression was found in non-receptive AN3CA cells.