Deoxyribonucleic acid methyltransferases and methyl-CpG-binding domain proteins in human endometrium and endometriosis

Objective: To determine [1] expression levels of both DNA methyltransferases (DNMTs) and methyl-CpG-binding domain proteins (MBDs) in human endometrium throughout the menstrual cycle and in eutopic and ectopic endometrium of patients with endometriosis and [2] hormone responsiveness of DNMT and MBD expression in explant cultures of proliferative phase endometrium. Design: In vitro study. Setting: Academic medical center. Patient(s): Premenopausal women with and without endometriosis. Intervention(s): Explant cultures of proliferative phase endometrium were treated with vehicle, 17 beta-E(2), or a combination of E(2) and P (E(2) + P) for 24 hours. Main Outcome Measure(s): Expression levels of DNMT1, DNMT2, and DNMT3B and MBD1, MBD2, and MeCP2 with use of real-time quantitative polymerase chain reaction. Result(s): Expression levels of DNMT1 and MBD2 were significantly higher in secretory-phase endometrium compared with proliferative endometrium and menstrual endometrium. In explant cultures, treatment with E(2) + P resulted in significant up-regulation of DNMT1 and MBD2. Expression levels of several DNMTs and MBDs were significantly lower in endometriotic lesions compared with eutopic endometrium of women with endometriosis and disease-free controls. Conclusion(s): These findings suggest a role for DNMTs and MBDs in the growth and differentiation of the human endometrium and support the notion that endometriosis may be an epigenetic disease. (Fertil Steril (R) 2011;95:1421-7.