Endometrial transporters and cytochrome P450 family member in endometriosis

Purpose To investigate expression of molecular transporters and CYP4B1 in endometrium from women with and without endometriosis. Methods Expression of genes encoding proteins: ATP-binding cassette sub-family G member 1 (ABCG1), aquaporin 3 (AQP3), solute carrier family 16, member 6 (monocarboxylic acid transporter 7) (SLC16A6), and transmembrane emp24 protein transport domain containing 6 (TMED6), as well as a member of the cytochrome P450 family 4 subfamily B, polypeptide 1 (CYP4B1) were assessed by quantitative (Q)RT-PCR in proliferative (PE) and early secretory (ESE) endometrium from 27 normoovulatory women with and without endometriosis. Cellular localization of these proteins was determined by immunohistochemistry. Results In eutopic endometrial tissue from women without endometriosis, mRNA expression of ABCG1, CYP4B1, and SLC16A6 was significantly up-regulated in the PE to ESE transition. CYP4B1 mRNA in endometrium from women with disease increased significantly compared to samples from women without disease, while there was no change in ABCG1 and SLC16A6 mRNA levels. However, immunodetection of ABCG1, AQP3, and TMED6 was similar across cycle phases, and there was no significant difference in immunostaining intensity or localization between women with and without endometriosis. Conclusions Molecular transporters and CYP4B1 are expressed in human endometrium, and a role for transporters and CYP4B1 in normal endometrial function and in women with endometriosis remains to be determined.