Decidualization of the endometrium and endometriosis involves the morphological and biochemical reprogramming of the estrogen-primed proliferative stromal compartment under the continuing influence of progesterone. Here, we evaluated the involvement of microRNA in the decidualization processes of normal endometrial stromal cells (NESCs) and endometriotic cyst stromal cells (ECSCs). In vitro decidualization of NESCs and ECSCs was induced by long-term culture with a combination of 0.5 mmol/L of dibutyryl cyclic adenosine monophosphate and 100 nmol/L of dienogest. We investigated the effect of in vitro decidualization on the microRNA and messenger RNA (mRNA) expression profiles of the NESCs and ECSCs using global microarray techniques and an Ingenuity Pathways Analysis. Decidualization differentially enhanced the miR-30a-5p expression in the NESCs and the miR-210 expression in the ECSCs. The enhanced miR-30a-5p expression in the NESCs correlated with the increased mRNA expression of Krüppel-like factor 9 and period circadian clock 3 as well as the decreased mRNA expression of tolloid-like 1, tolloid-like 2, and paired-like homeodomain 1. The enhanced expression of miR-210 in the ECSCs correlated with the decreased mRNA expression of growth hormone receptor and thymidine kinase 1. Although there is no direct evidence, we speculate that the loss of miR-30a-5p-mediated mechanisms of decidualization and the acquisition of miR-210-mediated mechanisms of decidualization may be involved in the progesterone resistance in endometriosis. Further investigations are necessary to test this speculation.
Keywords: decidualization; endometriosis; endometrium; insulin-like growth factor 1; microRNA; prolactin.