Activated Platelets Induce Estrogen Receptor β Expression in Endometriotic Stromal Cells

Abstract

Background/Aims: Endometriosis is viewed first and foremost as an estrogen-dependent disease, featuring not only excessive estrogen production but also aberrant expression of estrogen receptors (ERs), particularly ERβ, that mediate the estrogen action. ERβ is the predominant ER in mediating estrogen action in endometriosis, and estrogen plays a vital role in the development of endometriosis; thus, ERβ is viewed as a strong candidate for therapeutic targeting. Given our recent finding that platelets aggregate in endometriotic lesions, we sought to investigate whether activated platelets can upregulate ERβ. Methods: Using primary endometriotic stromal cells derived from patients with ovarian endometriomas and platelets harvested from healthy donors, we performed real-time RT-PCR analysis of mRNA abundance (n = 8) and Western blot analysis of protein expression (n = 8) of ERα and ERβ when co-cultured with phosphate-buffered saline, platelets, thrombin alone, and platelets plus thrombin for 48 h. Results: Treatment of endometriotic stromal cells with activated platelets resulted in the upregulation of ERβ gene and protein expression. Conclusion: In the presence of aggregated and thus activated platelets in endometriotic lesions, ERβ, but not ERα, is upregulated in endometriotic stromal cells. Our result suggests that the use of antiplatelet therapy may have potential in the treatment of endometriosis.

In vitro evidence that platelet-rich plasma stimulates cellular processes involved in endometrial regeneration

“…In vitro, PRP upregulated the gene expression of ERalpha, ERbeta, and the progesterone receptor in cultured bovine endometrial cells [65], leading the authors to suggest that intrauterine infusion of PRP in cattle may improve their fertility [65,73]. Activated platelets also induced ERbeta (the predominant ER in mediating estrogen action in endometriosis), mRNA, and protein expression in endometriotic stromal cells from ovarian endometrioma [74]. In our study, we did not observe differential expression of estrogen or progesterone receptor transcripts in response to PRP or PPP treatment likely due to species differences and different source of human cells used compared to above studies.…”

Anti-platelet therapy is efficacious in treating endometriosis induced in mouse

“…Indeed, it has recently been shown that platelets can promote angiogenesis and cellular proliferation (Ding et al, 2015), and platelet depletion and the treatment with a recombinant P-selectin can effectively reduce lesion area in murine models of endometriosis (Ding et al, 2015;Guo et al, 2015a). Platelets also induce the expression of oestrogen receptor β (ERβ) in endometriotic stromal cells (Zhang et al, 2015), which has shown recently to modulate apoptosis complexes and the inflammasome to drive the pathogenesis of endometriosis (Han et al, 2015). Consistent with the role of platelets in endometriosis, it has recently been reported that women with endometriosis are in a hypercoagulable state, featuring elevated platelet activation in their peripheral blood (Wu et al, 2015).…”

Platelets induce increased estrogen production through NF-κB and TGF-β1 signaling pathways in endometriotic stromal cells

“…And this may explain as why ERβ, but not ERα, is overexpressed in endometriosis 35,36 . Incidentally or not, we have shown previously that ERβ expression can also be upregulated by activated platelets 73 .…”

“…cell culture and reagents. Endometriosis-derived primary human endometriotic stromal cells (HESCs) were isolated and cultured as reported previously 23,73 . Briefly, the endometriotic tissues were minced into small pieces of about 1 mm³ in size, after washing with DMEM/F-12 medium (Dulbecco's modified Eagle's medium/ Ham's F-12 medium, Hyclon, Logan, UT, USA) supplemented with 100 IU/mL penicillin and 100 mg/ml streptomycin (Invitrogen, Paisley, UK).…”

“…Preparation of platelets. Platelets, donated by healthy male volunteers who denied taking any medications for at least two weeks prior to donation after informed consent, were isolated from the whole blood samples by centrifugation at room temperature as reported previously 23,73 . The blood was first centrifuged at 150 g for 10 min, the supernatant platelet rich plasma (PRP) was then centrifuged at 300 g for 5 min, and the supernatant PRP was harvested again and then centrifuged at 1000 g for 14 min.…”