Temporal relationship between alterations in the gut microbiome and the development of polycystic ovary syndrome-like phenotypes in prenatally androgenized female mice.

It has been recently recognized that prenatal androgen exposure is involved in the development of polycystic ovary syndrome (PCOS) in adulthood. In addition, the gut microbiome in adult patients and rodents with PCOS differs from that of healthy individuals. Moreover, recent studies have suggested that the gut microbiome may play a causative role in the pathogenesis of PCOS.

Induction of aryl hydrocarbon receptor in granulosa cells by endoplasmic reticulum stress contributes to pathology of polycystic ovary syndrome.

Recent studies have uncovered the critical role of aryl hydrocarbon receptor (AHR) in various diseases, including obesity and cancer progression, independent of its previously identified role as a receptor for endocrine-disrupting chemicals (EDCs). We previously showed that endoplasmic reticulum (ER) stress, a newly recognized local factor in the follicular microenvironment, is activated in granulosa cells from patients with polycystic ovary syndrome (PCOS) and a mouse model of the disease. By affecting diverse functions of granulosa cells, ER stress contributes to PCOS pathology.

Accumulation of advanced glycation end products in follicles is associated with poor oocyte developmental competence.

Advanced glycation end products (AGEs) affect the follicular microenvironment. The close relationship between AGEs, proinflammatory cytokine production and activation of the unfolded protein response (UPR), which involves activating transcription factor 4 (ATF4), is crucial for regulation of various cellular functions. We examined whether accumulation of AGEs in follicles was associated with proinflammatory cytokine production and activation of the UPR in granulosa cells and decreased oocyte developmental competence.

Endoplasmic Reticulum Stress Activated by Androgen Enhances Apoptosis of Granulosa Cells via Induction of Death Receptor 5 in PCOS.

Polycystic ovary syndrome (PCOS) is associated with hyperandrogenism and growth arrest of antral follicles. Previously, we found that endoplasmic reticulum (ER) stress is activated in granulosa cells of antral follicles in PCOS, evidenced by activation of unfolded protein response (UPR) genes. Based on this observation, we hypothesized that ER stress is activated by androgens in granulosa cells of antral follicles, and that activated ER stress promotes apoptosis via induction of the UPR transcription factor C/EBP homologous protein (CHOP) and subsequent activation of death receptor (DR) 5.

Activation of Endoplasmic Reticulum Stress in Granulosa Cells from Patients with Polycystic Ovary Syndrome Contributes to Ovarian Fibrosis.

Recent studies report the involvement of intra-ovarian factors, such as inflammation and oxidative stress, in the pathophysiology of polycystic ovary syndrome (PCOS), the most common endocrine disorder of reproductive age women. Endoplasmic reticulum (ER) stress is a local factor that affects various cellular events during a broad spectrum of physiological and pathological conditions. It may also be an important determinant of pro-fibrotic remodeling during tissue fibrosis.

Evidence of the activation of unfolded protein response in granulosa and cumulus cells during follicular growth and maturation.

The objective of the present study is to investigate whether unfolded protein response (UPR), activated by endoplasmic reticulum (ER) stress, in granulosa cells (GC) and cumulus cells (CC) is involved in the process of follicular growth and maturation. First, to examine the presence of UPR in growing follicles, the expression of spliced form of X-box-binding protein 1 (XBP1(S)) and heat shock 70 kDa protein 5 (HSPA5) mRNA, typical UPR genes, in mice ovaries were examined by in situ hybridization. GC of later stage than large secondary follicles expressed both XBP1(S) and HSPA5 mRNA, which was accompanied with the activation of ER stress sensor proteins, inositol-requiring enzyme 1 (IRE1) and double-stranded RNA-activated protein kinase-like ER kinase (PERK), confirmed by immunohistochemistry.

Bone morphogenetic protein-2 (BMP-2) increases gene expression of FSH receptor and aromatase and decreases gene expression of LH receptor and StAR in human granulosa cells.

Problem: A growing body of evidence indicates that bone morphogenetic protein (BMP) cytokines play a key role in female fertility in mammals. BMP-2 is known to be expressed in the ovary of many species. In the present study, we examined the expression and function of BMP-2 in the human ovary.

Interleukin-4 stimulates proliferation of endometriotic stromal cells.

Several lines of evidence indicate that the Th2 immune response is associated with endometriosis. Although an increased concentration of interleukin (IL)-4, a typical Th2 cytokine, has been reported in endometriotic tissues, the implication of this for endometriosis has not been determined. To investigate a possible role of IL-4 in the development of endometriosis, we examined the presence of IL-4-producing cells in endometriotic tissues and the effect of IL-4 on proliferation of endometriotic stromal cells.

Interleukin (IL)-17A stimulates IL-8 secretion, cyclooxygensase-2 expression, and cell proliferation of endometriotic stromal cells.

IL-17A is secreted from Th17 cells, a discovery leading to revision of the mechanism underlying the role of Th1/Th2 in the immune response. Strong evidence suggests that immune responses associated with inflammation are involved in the pathogenesis of endometriosis. In the present study, we first demonstrated that the presence of Th17 cells in peritoneal fluid of endometriotic women by flow cytometric analysis and IL-17A-positive cells in endometriotic tissues by immunohistochemistry.

The presence of midkine and its possible implication in human ovarian follicles.

Problem: Ovarian follicles undergo a dynamic change to provide a mature ovum, and the process involves angiogenesis, follicular cell proliferation and leukocyte recruitment. Midkine (MK) is a heparin-binding growth factor that has angiogenic, mitogenic, and chemotactic activities. In the present study, we investigated the presence of MK and its possible role in human ovarian follicles.

Metformin suppresses interleukin (IL)-1beta-induced IL-8 production, aromatase activation, and proliferation of endometriotic stromal cells.

Context: Metformin, a widely used treatment for diabetes that improves insulin sensitivity, also has both antiinflammatory properties and a modulatory effect on ovarian steroid production, two actions that have been suggested to be efficacious in therapy for endometriosis.

Objective: To determine whether metformin may be effective for the treatment of endometriosis, we evaluated the effects of this agent on inflammatory response, estradiol production, and proliferation of endometriotic stromal cells (ESCs).

Design: ESCs derived from ovarian endometriomas were cultured with various concentrations of metformin.

Expression of toll-like receptors 2, 3, 4, and 9 genes in the human endometrium during the menstrual cycle.

Innate immunity in the endometrium has fundamental significance for reproduction. Although toll-like receptors (TLRs) play central roles in innate immune responses, their expression in the human endometrium remains to be fully elucidated. We have examined the gene expression of TLR2, TLR3, TLR4, and TLR9 in endometrial tissues by real-time quantitative PCR and in situ hybridization.

The expression and possible roles of chemokine CXCL11 and its receptor CXCR3 in the human endometrium.

IFN-gamma secreted by a human embryo and trophoblast cells during implantation is suggested to play an important role in implantation and pregnancy. In the present study, we explored expression and possible functions of CXCL11, a CXC chemokine strongly induced by IFN-gamma, and its receptor CXCR3 in the human endometrium. Secreted CXCL11 protein was not detected in cultured endometrial stromal cells (ESC) but was detected in cultured endometrial epithelial cells (EEC).

Possible involvement of thrombin/protease-activated receptor 1 system in the pathogenesis of endometriosis.

Endometriosis is known to be associated with local inflammatory reactions. Given the emerging concept of thrombin and its specific receptor, protease-activated receptor 1 (PAR1), as important players in inflammation and cell proliferation, we investigated whether thrombin and PAR1 might be involved in the pathophysiology of the disease, using a primary cell culture system of endometriotic tissues. PAR1 mRNA was expressed in primary endometriotic stromal cells (ESCs).

Evidence for the presence of protease-activated receptor 2 and its possible implication in remodeling of human endometrium.

Protease-activated receptor 2 (PAR2) is activated by various proteases released from the leukocytes, such as neutrophils and mast cells. Because these leukocytes reside in the endometrium, we speculated that PAR2 might be activated there. In this study, we investigated the presence and possible roles of PAR2 in the endometrium.

Identification of surrogate ligands for orphan G protein-coupled receptors.

We prepared fusion proteins with an alpha subunit of G protein Gi (Gi1alpha) of 26 orphan G protein-coupled receptors (GPCRs) and with Gsalpha of 10 orphan GPCRs, most of which had been identified from the human genome previously [FEBS Lett 520 (2002) 97]. Ligands for these fusion proteins were screened from a library consisting of approximately 1000 authentic compounds by measuring their effect on [35S]GTPgammaS binding to membrane preparations of insect Sf9 cells expressing these fusion proteins. Eleven compounds were found to act as surrogate agonists for a GPCR-Gsalpha and four GPCR-Gialpha fusion proteins, a compound as an inverse agonist for two GPCR-Gsalpha fusion proteins, and a compound as an endogenous agonist for a GPCR-Gialpha fusion protein.

Possible roles of thrombin-induced activation of protease-activated receptor 1 in human luteinized granulosa cells.

The presence of thrombin and its receptor, protease-activated receptor 1 (PAR 1), in the ovary suggests that thrombin may regulate ovarian function. In particular, to address the possible role of thrombin in ovulation, a phenomenon displaying mimicry of inflammation, we investigated the effects of thrombin and PAR 1 on the production of inflammation-related substances in human luteinized granulosa cells (LGC). Thrombin stimulated the production of IL-8 and monocyte chemoattractant protein-1 by cultured LGC.