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Background: Endometriosis is a complex syndrome characterized by an estrogen-dependent chronic inflammatory process that affects 10% of women of reproductive age. Ovarian endometriosis (OE) is the most common lesion in endometriosis and may cause infertility, in addition to dysmenorrhea. Hormonal treatments, which are the conventional treatment methods for endometriosis, suppress ovulation and hence are not compatible with fertility. The inflammasome is a complex that includes Nod-like receptor (NLR) family proteins, which sense pathogen-associated molecular patterns and homeostasis-altering molecular processes. It has been reported that the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing (NLRP) 3 inflammasome, which contributes to the activation of interleukin-1 beta (IL-1β), might be related to the progression of endometriosis. Therefore, the aim of the present study was to evaluate non-hormonal therapies for OE, such as inhibitors of the NLRP3 inflammasome. Methods: The expression of NLRP3 was measured in the eutopic endometrium (EM) of patients with and without endometriosis and OE samples, as well as stromal cells derived from the endometrium of patients with and without endometriosis and OE samples (endometrial stromal cells with endometriosis [ESCs] and cyst-derived stromal cells [CSCs]). The effects of an NLRP3 inhibitor (MCC950) on ESCs and CSCs survival and IL-1β production were evaluated. We then administered MCC950 to a murine model of OE to evaluate its effects on OE lesions and ovarian function. Results: NLRP3 gene and protein expression levels were higher in OE and CSCs than in EM and ESCs, respectively. MCC950 treatment significantly reduced the survival of CSCs, but not that of ESCs. Moreover, MCC950 treatment reduced the co-localization of NLRP3 and IL-1β in CSCs, as well as IL-1β concentrations in CSCs supernatants. In the murine model, MCC950 treatment reduced OE lesion size compared to phosphate-buffered saline treatment (89 ± 15 vs. 49 ± 9.3 mm3 per ovary; P < 0.05). In the MCC950-treated group, IL-1β and Ki67 levels in the OE-associated epithelia were reduced along with the oxidative stress markers of granulosa cells. Conclusions: These results indicated that NLRP3/IL-1β is involved in the pathogenesis of endometriosis and that NLRP3 inhibitors may be useful for suppressing OE and improving the function of ovaries with endometriosis. [ABSTRACT FROM AUTHOR]

Several features exist that distinguish endometriotic cells from eutopic endometrial cells. Progesterone resistance is one of the main distinguishing features, although how progesterone resistance affects the phenotype of endometriotic cells is not fully elucidated. Heart and neural crest derivatives expressed 2 (HAND2) is a transcriptional factor that plays an important role in maintaining endometrial function in a progesterone-dependent manner. Therefore, we explored whether progesterone-dependent HAND2 is implicated in the progression of endometriosis. HAND2 was less expressed by endometriotic tissues compared to endometrial tissues. Suppression of HAND2 expression induced fibroblast growth factor 1 (FGF1), FGF2, and FGF9 in endometriotic stromal cells and consequently enhanced migration and invasion capacity. AZD4547, a FGF receptor inhibitor, diminished the migration and invasion of endometriotic cells in vitro. In the murine model of endometriosis, AZD4547 showed suppressive effects on the development of endometriotic lesions at a relatively low concentration. In conclusion, we demonstrated that FGF1, FGF2, and FGF9 are downstream effectors of HAND2 in endometriotic cells. Since HAND2-dependent FGFs play roles in enhancing invasive capacity of endometriotic cells, our results suggest that FGF receptor inhibitors, such as AZD4547, can be promising therapeutic targets for endometriosis. [ABSTRACT FROM AUTHOR]

A reduced response to progesterone in the eutopic endometrium with endometriosis and in endometriotic tissues is considered to be the underlying factor for endometriosis. CD10 is known to be expressed by endometrial and endometriotic stromal cells and may be induced by progestins, although the function of CD10 is not fully revealed in endometrial or endometriotic tissues. In the current study, the expression of CD10 was significantly increased by treatment of the cells with progesterone, 17β-estradiol, and dibutyryl cyclic adenosine monophosphate (cAMP) in the endometrial stromal cells. On the other hand, the expression of CD10 following treatment with progesterone, 17β-estradiol, and dibutyryl cAMP was not significantly increased in endometriotic stromal cells. The adhesion assay for endometrial and endometriotic stromal cells to hyaluronan using 5- or 6-(N-succinimidyloxycarbonyl)-fluorescein 3', 6'-diacetate–labeled cells demonstrated that the CD44-dependent adhesion of stromal cells was inhibited by CD10. As far as the induction of CD10 is concerned, the effect of progesterone was different between endometrial stromal cells and endometriotic stromal cells. CD10 might be involved in the development of endometriosis due to its influence on CD44-dependent cell adhesion. [ABSTRACT FROM PUBLISHER]