Deciphering the Role of PGRMC1 During Human Decidualization Using an In Vitro Approach

Abstract

Context Non-classical membrane progesterone receptor (mPRs) and PGRMC1 expression have been detected in endometrium, but their role in decidualization was not yet investigated. We previously demonstrated PGRMC1 downregulation in receptive endometrium and that its overexpression inhibits decidualization. Furthermore, during decidualization, PGRMC1 mainly interacts with proteins involved in biosynthesis, intracellular transport and mitochondrial activity. Objective To determine PGRMC1 and mPRs signaling role during decidualization. Design and Interventions Isolated primary endometrial stromal cells (EnSC) were in vitro decidualized in presence of classic stimuli (E2+P4), PGRMC1 inhibitor (AG205), or membrane-impermeable P4 (P4-BSA). Setting and Participants Endometrial biopsies from 19 fertile oocyte donors attending IVI-Valencia IVF clinic. Main Outcome Measure(s) EnSC decidualization was evaluated by prolactin ELISA and F-actin immunostaining. Progesterone receptor localization was evaluated by immunofluorescence. EnSC transcriptomic profiles were analyzed by microarray technology. Result(s) PGRMC1 inhibition during EnSC decidualization (AG205dEnSC) does not interfere with EnSC cytoskeletal rearrangements and prolactin secretion. However, global transcriptional profiling revealed more differentially expressed genes in AG205dEnSC than in dEnSC, compared with non-decidualized EnSC (ndEnSC). In silico analysis showed that PGRMC1 inhibition upregulated more genes related to metabolism, molecular transport, and hormonal biosynthesis compared to control dEnSC. EnSC decidualized in the presence of P4-BSA showed a similar behavior as ndEnSC in terms of morphological features, absence of prolactin secretion, and transcriptomic pattern. Conclusion(s) Our findings associate PGRMC1 to hormonal biosynthesis, metabolism, and vesicular transport—important cellular functions for dEnSC supporting pregnancy. Activation of membrane P4 receptor signaling alone was unable to induce downstream effects needed for proper decidualization.

AG-205 Upregulates Enzymes Involved in Cholesterol Biosynthesis and Steroidogenesis in Human Endometrial Cells Independently of PGRMC1 and Related MAPR Proteins

“…In both tested cells lines-T-HESC cells from fibroblastic origin and HEC-1A from epithelial origin-the most striking effect of AG-205 highlighted by our transcriptomic analyses was increased mRNA concentration of several enzymes involved in cholesterol biosynthesis, the sterol-sensitive regulator INSIG1 and specific enzymes involved in steroidogenesis. Our results are in global agreement with the reported effects of AG-205 in the culture of primary stromal cells induced to decidualize in response to combined estradiol and progesterone [14]. However, these effects were produced in the absence of progesterone, suggesting that they are not relevant to decidualization, and, most importantly, they were not mimicked by siRNA-mediated down-regulation of PGRMC1 or any other related MAPR (PGRMC2, NENF or CYB5D2).…”

“…In the human endometrium, progesterone is a critical inducer of modifications occurring to favour blastocyst implantation and pregnancy, including decidualization, i.e., a specific differentiation of the endometrial stromal cells. PGRMC1 is expressed in the human endometrium and its potential contribution to decidualization was recently reported [14]. Interestingly, the addition of AG-205 to endometrial stromal cells undergoing artificial decidualization in response to progesterone (combined with estradiol) upregulated expression of genes related to metabolism, molecular transport and hormonal biosynthesis.…”

PGRMC1 Regulates Cellular Senescence via Modulating FOXO1 Expression in Decidualizing Endometrial Stromal Cells

“…We and others previously demonstrated that endometrial PGRMC1 expression decreases during the secretory phase of the menstrual cycle and the small interfering RNA (siRNA)-mediated knockdown and inhibition of PGRMC1 promotes ESC decidualization in vitro [ 26 , 27 ]. However, the relationship between the PGRMC1 expression and cellular senescence in ESCs during decidualization has not been explored.…”

Functional Implications of Estrogen and Progesterone Receptors Expression in Adenomyosis, Potential Targets for Endocrinological Therapy

“…It is well known that progesterone stimulates the endometrium to directly synthesize prolactin [ 48 , 49 ]. We detected the upregulation of prolactin secretion in adenomyosis in the same pattern as in the normal endometrium, mediated by both cAMP and progesterone.…”