Chemokine Ligand 20: A Signal for Leukocyte Recruitment During Human Ovulation?

Ovarian microenvironment: challenges and opportunities in protecting against chemotherapy-associated ovarian damage

BACKGROUND

Chemotherapy-associated ovarian damage (CAOD) is one of the most feared short- and long-term side effects of anticancer treatment in premenopausal women. Accumulating detailed data show that different chemotherapy regimens can lead to disturbance of ovarian hormone levels, reduced or lost fertility, and an increased risk of early menopause. Previous studies have often focused on the direct effects of chemotherapeutic drugs on ovarian follicles, such as direct DNA damage-mediated apoptotic death and primordial follicle burnout. Emerging evidence has revealed an imbalance in the ovarian microenvironment during chemotherapy. The ovarian microenvironment provides nutritional support and transportation of signals that stimulate the growth and development of follicles, ovulation, and corpus luteum formation. The close interaction between the ovarian microenvironment and follicles can determine ovarian function. Therefore, designing novel and precise strategies to manipulate the ovarian microenvironment may be a new strategy to protect ovarian function during chemotherapy.

OBJECTIVE AND RATIONALE

This review details the changes that occur in the ovarian microenvironment during chemotherapy and emphasizes the importance of developing new therapeutics that protect ovarian function by targeting the ovarian microenvironment during chemotherapy.

SEARCH METHODS

A comprehensive review of the literature was performed by searching PubMed up to April 2024. Search terms included 'ovarian microenvironment' (ovarian extracellular matrix, ovarian stromal cells, ovarian interstitial, ovarian blood vessels, ovarian lymphatic vessels, ovarian macrophages, ovarian lymphocytes, ovarian immune cytokines, ovarian oxidative stress, ovarian reactive oxygen species, ovarian senescence cells, ovarian senescence-associated secretory phenotypes, ovarian oogonial stem cells, ovarian stem cells), terms related to ovarian function (reproductive health, fertility, infertility, fecundity, ovarian reserve, ovarian function, menopause, decreased ovarian reserve, premature ovarian insufficiency/failure), and terms related to chemotherapy (cyclophosphamide, lfosfamide, chlormethine, chlorambucil, busulfan, melphalan, procarbazine, cisplatin, doxorubicin, carboplatin, taxane, paclitaxel, docetaxel, 5-fluorouraci, vincristine, methotrexate, dactinomycin, bleomycin, mercaptopurine).

OUTCOMES

The ovarian microenvironment shows great changes during chemotherapy, inducing extracellular matrix deposition and stromal fibrosis, angiogenesis disorders, immune microenvironment disturbance, oxidative stress imbalances, ovarian stem cell exhaustion, and cell senescence, thereby lowering the quantity and quality of ovarian follicles. Several methods targeting the ovarian microenvironment have been adopted to prevent and treat CAOD, such as stem cell therapy and the use of free radical scavengers, senolytherapies, immunomodulators, and proangiogenic factors.

WIDER IMPLICATIONS

Ovarian function is determined by its 'seeds' (follicles) and 'soil' (ovarian microenvironment). The ovarian microenvironment has been reported to play a vital role in CAOD and targeting the ovarian microenvironment may present potential therapeutic approaches for CAOD. However, the relation between the ovarian microenvironment, its regulatory networks, and CAOD needs to be further studied. A better understanding of these issues could be helpful in explaining the pathogenesis of CAOD and creating innovative strategies for counteracting the effects exerted on ovarian function. Our aim is that this narrative review of CAOD will stimulate more research in this important field.

REGISTRATION NUMBER

Not applicable.

New insight into the role of macrophages in ovarian function and ovarian aging

Macrophages (MΦs) are the most abundant leukocytes in mammalian ovaries that have heterogeneity and plasticity. A body of evidence has indicated that these cells are important in maintaining ovarian homeostasis and they play critical roles in ovarian physiological events, such as folliculogenesis, ovulation, corpus luteum formation and regression. As females age, ovarian tissue microenvironment is typified by chronic inflammation with exacerbated ovarian fibrosis. In response to specific danger signals within aged ovaries, macrophages polarize into different M1 or M2 phenotypes, and specialize in unique functions to participate in the ovarian aging process. In this review, we will focus on the physiologic roles of MΦs in normal ovarian functions. Furthermore, we will discuss the roles of MΦs in the process of ovarian senescence, as well as the novel techniques applied in this field.

Exposure to a phthalate mixture disrupts ovulatory progesterone receptor signaling in human granulosa cells in vitro†

Exposure to phthalates disrupts ovarian function. However, limited studies have investigated the effects of phthalate mixtures on ovulation, especially in women. Human granulosa cells were used to test the hypothesis that exposure to a phthalate mixture (PHTmix) disrupts progesterone (P4)/progesterone receptor (PGR) signaling, which is a crucial pathway for ovulation. In addition, progestin and cyclic adenosine 3', 5'-monophosphate (cAMP) supplementation were tested as methods to circumvent phthalate toxicity. Granulosa cells from women undergoing in vitro fertilization were acclimated in culture to regain responsiveness to human chorionic gonadotropin (hCG; clinical luteinizing hormone analogue). Granulosa cells were treated with or without hCG, and with or without PHTmix (1-500 μg/ml; dimethylsulfoxide = vehicle control) for 0.5-36 h. In the supplementation experiments, cells were treated with or without R5020 (stable progestin), and with or without 8-Br-cAMP (stable cAMP analogue). Exposure to hCG + PHTmix decreased P4 levels and mRNA levels of steroidogenic factors when compared to hCG. This was accompanied by decreased mRNA levels of PGR and downstream P4/PGR ovulatory mediators (ADAM metallopeptidase with thrombospondin type 1 motif 1 (ADAMTS1), C-X-C motif chemokine receptor 4 (CXCR4), pentraxin 3 (PTX3), and regulator of G protein signaling 2 (RGS2)) in the hCG + PHTmix groups compared to hCG. Exposure to hCG + PHTmix 500 μg/ml decreased cAMP levels and protein kinase A activity compared to hCG. Supplementation with progestin in the hCG + PHTmix 500 μg/ml group did not rescue toxicity, while supplementation with cAMP restored PGR levels and downstream P4/PGR mediator levels to hCG levels. These findings suggest that phthalate mixture exposure inhibits P4/PGR signaling in human granulosa cells via decreased steroidogenesis, cAMP levels, and protein kinase A activity. Restored P4/PGR signaling with cAMP supplementation provides a potential cellular target for intervention of phthalate-induced ovulatory dysfunction in women.

Cortisol/glucocorticoid receptor: a critical mediator of the ovulatory process and luteinization in human periovulatory follicles

STUDY QUESTION

Do cortisol/glucocorticoid receptors play an active role in the human ovary during ovulation and early luteinization?

SUMMARY ANSWER

The ovulatory hCG stimulation-induced glucocorticoid receptor signaling plays a crucial role in regulating steroidogenesis and ovulatory cascade in human periovulatory follicles.

WHAT IS KNOWN ALREADY

Previous studies reported an increase in cortisol levels in the human follicular fluid after the LH surge or ovulatory hCG administration. However, little is known about the role of cortisol/glucocorticoid receptors in the ovulatory process and luteinization in humans.

STUDY DESIGN, SIZE, DURATION

This study was an experimental prospective clinical and laboratory-based study. An in vivo experimental study was accomplished utilizing the dominant ovarian follicles from 38 premenopausal women undergoing laparoscopic sterilization. An in vitro experimental study was completed using the primary human granulosa/lutein cells (hGLC) from 26 premenopausal women undergoing IVF.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study was conducted in a private fertility clinic and academic medical centers. Dominant ovarian follicles were collected before the LH surge and at defined times after hCG administration from women undergoing laparoscopic sterilization. Primary hGLC were collected from women undergoing IVF. hGLC were treated without or with hCG in the absence or presence of RU486 (20 µM; dual antagonist for progesterone receptor and glucocorticoid receptor) or CORT125281 (50 µM; selective glucocorticoid receptor antagonist) for 12 or 36 h. The expression of genes involved in glucocorticoid receptor signaling, steroidogenesis, and ovulatory cascade was studied with RT-quantitative PCR and western blotting. The production of cortisol, corticosterone, and progesterone was assessed by hormone assay kits.

MAIN RESULTS AND THE ROLE OF CHANCE

hCG administration upregulated the expression of hydroxysteroid 11-beta dehydrogenase 1 (HSD11B1), nuclear receptor subfamily 3 group C member 1 (NR3C1), FKBP prolyl isomerase 5 (FKBP5), and FKBP prolyl isomerase 4 (FKBP4) in human ovulatory follicles and in hGLC (P < 0.05). RU486 and CORT125281 reduced hCG-induced increases in progesterone and cortisol production in hGLC. The expression of genes involved in glucocorticoid receptor signaling, steroidogenesis, and the key ovulatory process was reduced by RU486 and/or CORT125281 in hGLC.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The role of cortisol/glucocorticoid receptors demonstrated using the hGLC model may not fully reflect their physiological roles in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

Successful ovulation and luteinization are essential for female fertility. Women with dysregulated cortisol levels often suffer from anovulatory infertility. Deciphering the functional role of glucocorticoid receptor signaling in human periovulatory follicles enhances our knowledge of basic ovarian physiology and may provide therapeutic insights into treating infertility in women.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by P01HD71875 (to M.J., T.E.C., and M.B.) and R01HD096077 (to M.J.) from the Foundation for the National Institutes of Health and the BTPSRF of the University of Kentucky Markey Cancer Center (P30CA177558). The authors report no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

A single-cell gene expression atlas of human follicular aspirates: Identification of leukocyte subpopulations and their paracrine factors

Leukocytes are in situ regulators critical for ovarian function. However, little is known about leukocyte subpopulations and their interaction with follicular cells in ovulatory follicles, especially in humans. Single-cell RNA sequencing (scRNA-seq) was performed using follicular aspirates obtained from four IVF patients and identified 13 cell groups: one granulosa cell group, one thecal cell group, 10 subsets of leukocytes, and one group of RBC/platelet. RNA velocity analyses on five granulosa cell populations predicted developmental dynamics denoting two projections of differentiation states. The cell type-specific transcriptomic profiling analyses revealed the presence of a diverse array of leukocyte-derived factors that can directly impact granulosa cell function by activating their receptors (e.g., cytokines and secretory ligands) and are involved in tissue remodeling (e.g., MMPs, ADAMs, ADAMTSs, and TIMPs) and angiogenesis (e.g., VEGFs, PGF, FGF, IGF, and THBS1) in ovulatory follicles. Consistent with the findings from the scRNA-seq data, the leukocyte-specific expression of CD68, IL1B, and MMP9 was verified in follicle tissues collected before and at defined hours after hCG administration from regularly cycling women. Collectively, this study demonstrates that this data can be used as an invaluable resource for identifying important leukocyte-derived factors that promote follicular cell function, thereby facilitating ovulation and luteinization in women.

In vitro effects of PPAR gamma ligands on gene expression in corpus luteum explants in non-pregnant pigs - Transcriptome analysis

The corpus luteum (CL) is a temporary endocrine structure in the female ovaries that develops cyclically in mature females during luteinization. This study aimed to determine the in vitro effects of peroxisome proliferator-activated receptor gamma (PPARγ) ligands on the transcriptomic profile of the porcine CL in the mid- and late-luteal phase of the estrous cycle using RNA-seq technology. The CL slices were incubated in the presence of PPARγ agonist - pioglitazone or antagonist - T0070907. We identified 40 differentially expressed genes after treatment with pioglitazone and 40 after treatment with T0070907 in the mid-luteal phase as well as 26 after pioglitazone and 29 after T0070907 treatment in the late-luteal phase of the estrous cycle. In addition, we detected differences in gene expression between the mid- and late-luteal phase without treatment (409 differentially expressed genes). This study revealed a number of novel candidate genes that may play a role in controlling the function of CL by regulating signaling pathways related to ovarian steroidogenesis, metabolic processes, cell differentiation, apoptosis, and immune responses. These findings become a basis for further studies to explain the mechanism of PPARγ action in the reproductive system.

The effects of endocrine-disrupting chemicals on ovarian- and ovulation-related fertility outcomes

Exposure to endocrine-disrupting chemicals (EDCs) is unavoidable, which represents a public health concern given the ability of EDCs to target the ovary. However, there is a large gap in the knowledge about the impact of EDCs on ovarian function, including the process of ovulation. Defects in ovulation are the leading cause of infertility in women, and EDC exposures are contributing to the prevalence of infertility. Thus, investigating the effects of EDCs on the ovary and ovulation is an emerging area for research and is the focus of this review. The effects of EDCs on gametogenesis, uterine function, embryonic development, and other aspects of fertility are not addressed to focus on ovarian- and ovulation-related fertility issues. Herein, findings from epidemiological and basic science studies are summarized for several EDCs, including phthalates, bisphenols, per- and poly-fluoroalkyl substances, flame retardants, parabens, and triclosan. Epidemiological literature suggests that exposure is associated with impaired fecundity and in vitro fertilization outcomes (decreased egg yield, pregnancies, and births), while basic science literature reports altered ovarian follicle and corpora lutea numbers, altered hormone levels, and impaired ovulatory processes. Future directions include identification of the mechanisms by which EDCs disrupt ovulation leading to infertility, especially in women.

Single-Cell Sequencing Reveals an Intrinsic Heterogeneity of the Preovulatory Follicular Microenvironment

The follicular microenvironment, including intra-follicular granulosa cells (GCs), is responsible for oocyte maturation and subsequent ovulation. However, the functions of GCs and cellular components of the follicular microenvironment in preovulatory follicles have not been extensively explored. Here, we surveyed the single-cell transcriptome of the follicular microenvironment around MII oocytes in six human preovulatory follicles in in vitro fertilization. There were six different cell types in the preovulatory follicles, including GCs and various immune cells. In GCs, we identified nine different functional clusters with different functional transcriptomic profiles, including specific clusters involved in inflammatory responses and adhesive function. Follicular macrophages are involved in immune responses, extracellular matrix remoulding and assist GCs in promoting the oocyte meiotic resumption. Interestingly, we observed that the specific terminal state subcluster of GCs with high levels of adhesive-related molecules should result in macrophage recruitment and residence, further contributing to an obvious heterogeneity of the immune cell proportion in preovulatory follicles from different patients. Our results provide a comprehensive understanding of the transcriptomic landscape of the preovulatory follicular microenvironment at the single-cell level. It provides valuable insights into understanding the regulation of the oocyte maturation and ovulation process, offering potential clues for the diagnosis and treatment of oocyte-maturation-related and ovulation-related diseases.

Hydroxysteroid 17-Beta Dehydrogenase 6 Is a Prognostic Biomarker and Correlates with Immune Infiltrates in Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a common malignancy worldwide with poor outcomes. Therefore, it is important to identify a valuable prognostic biomarker for HCC. The present study aimed to identify novel prognostic biomarkers for HCC and evaluate the potential role of hub genes in HCC.

METHODS

Weighted gene co-expression network analysis and protein-protein interaction analysis were performed to identify important potential prognostic genes. The expression of hub genes was confirmed by the GEPIA, Oncomine, UALCAN, and HPA database. Furthermore, survival analysis of hub genes was performed using the Kaplan-Meier plotter database. Finally, we investigated the association between hub genes and immune factors in HCC through GSEA, the TIMER, and TISIDB database.

RESULTS

HSD17B6 expression was significantly lower in HCC than in normal tissues. Low HSD17B6 expression is associated with poorer overall survival and progression-free survival in HCC patients, particularly at medium disease stages (stage II and III or grade III). HSD17B6 showed a strong correlation with tumor-infiltrating B cells, CD4 + and CD8 + T cells, macrophages, neutrophils, and dendritic cells. Somatic copy number alteration might be the main cause of the negative correlation between HSD17B6 expression and immune infiltration. HSD17B6 expression in HCC negatively correlated with the expression of several immune cell markers, including exhausted T cell markers, PD-1 and CTLA-4, suggesting its role in regulating tumor immunity.

CONCLUSIONS

HSD17B6 is a potential prognostic biomarker that determines cancer progression and is correlated with tumor immune cells infiltration in HCC.

Ovulatory upregulation of angiotensin-converting enzyme 2, a receptor for SARS-CoV-2, in dominant follicles of the human ovary

OBJECTIVE

To determine the temporal expression of angiotensin-converting enzyme 2 (ACE2), a receptor for SARS-CoV-2, in dominant follicles throughout the periovulatory period in women and the regulatory mechanisms underlying ACE2 expression in human granulosa/lutein cells (hGLC).

DESIGN

Experimental prospective clinical study and laboratory-based investigation.

SETTING

University Medical Center and private in vitro fertilization center.

PATIENT(S)

Thirty premenopausal women undergoing surgery for tubal ligation and 16 premenopausal women undergoing in vitro fertilization.

INTERVENTION(S)

Administration of human chorionic gonadotropin (hCG) and harvesting of preovulatory/ovulatory follicles by timed laparoscopy, and collection of granulosa/lutein cells and cumulus cells at the time of oocyte retrieval.

MAIN OUTCOME MEASURE(S)

Expression and localization of ACE2 in granulosa cells and dominant follicles collected throughout the periovulatory period of the menstrual cycle and in hGLC using quantitative polymerase chain reaction, immunoblotting, and immunohistochemistry.

RESULT(S)

ACE2 expression (mRNA and protein) is up-regulated in human ovulatory follicles after administration of hCG. ACE2 expression was higher in cumulus cells than in granulosa cells. hCG increased the expression of ACE2 in primary hGLC cultures; the increase was inhibited by RU486 (an antagonist for progesterone receptor and glucocorticoid receptor) and CORT125281 (a selective glucocorticoid receptor antagonist), but not by AG1478 (an EGF receptor tyrosine kinase inhibitor) or by dexamethasone.

CONCLUSION(S)

The hormone-regulated expression of ACE2 in granulosa cells suggests a potential role of ACE2 in the ovulatory process. These data also imply the possible impact of COVID-19 on a vital cyclic event of ovarian function and thus on women's overall reproductive health. However, SAR-CoV-2 infection in ovarian cells in vivo or in vitro has yet to be determined.

The FOS/AP-1 Regulates Metabolic Changes and Cholesterol Synthesis in Human Periovulatory Granulosa Cells

FOS, a subunit of the activator protein-1 (AP-1) transcription factor, has been implicated in various cellular changes. In the human ovary, the expression of FOS and its heterodimeric binding partners JUN, JUNB, and JUND increases in periovulatory follicles. However, the specific role of the FOS/AP-1 remains elusive. The present study determined the regulatory mechanisms driving the expression of FOS and its partners and functions of FOS using primary human granulosa/lutein cells (hGLCs). Human chorionic gonadotropin (hCG) induced a biphasic increase in the expression of FOS, peaking at 1 to 3 hours and 12 hours. The levels of JUN proteins were also increased by hCG, with varying expression patterns. Coimmunoprecipitation analyses revealed that FOS is present as heterodimers with all JUN proteins. hCG immediately activated protein kinase A and p42/44MAPK signaling pathways, and inhibitors for these pathways abolished hCG-induced increases in the levels of FOS, JUN, and JUNB. To identify the genes regulated by FOS, high-throughput RNA sequencing was performed using hGLC treated with hCG ± T-5224 (FOS inhibitor). Sequencing data analysis revealed that FOS inhibition affects the expression of numerous genes, including a cluster of genes involved in the periovulatory process such as matrix remodeling, prostaglandin synthesis, glycolysis, and cholesterol biosynthesis. Quantitative PCR analysis verified hCG-induced, T-5224-regulated expression of a selection of genes involved in these processes. Consistently, hCG-induced increases in metabolic activities and cholesterol levels were suppressed by T-5224. This study unveiled potential downstream target genes of and a role for the FOS/AP-1 complex in metabolic changes and cholesterol biosynthesis in granulosa/lutein cells of human periovulatory follicles.

Two waves of transcriptomic changes in periovulatory human granulosa cells

STUDY QUESTION

How does the human granulosa cell (GC) transcriptome change during ovulation?

SUMMARY ANSWER

Two transcriptional peaks were observed at 12 h and at 36 h after induction of ovulation, both dominated by genes and pathways known from the inflammatory system.

WHAT IS KNOWN ALREADY

The crosstalk between GCs and the oocyte, which is essential for ovulation and oocyte maturation, can be assessed through transcriptomic profiling of GCs. Detailed transcriptional changes during ovulation have not previously been assessed in humans.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study comprised 50 women undergoing fertility treatment in a standard antagonist protocol at a university hospital-affiliated fertility clinic in 2016-2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

From each woman, one sample of GCs was collected by transvaginal ultrasound-guided follicle aspiration either before or 12 h, 17 h or 32 h after ovulation induction (OI). A second sample was collected at oocyte retrieval, 36 h after OI. Total RNA was isolated from GCs and analyzed by microarray. Gene expression differences between the five time points were assessed by ANOVA with a random factor accounting for the pairing of samples, and seven clusters of protein-coding genes representing distinct expression profiles were identified. These were used as input for subsequent bioinformatic analyses to identify enriched pathways and suggest upstream regulators. Subsets of genes were assessed to explore specific ovulatory functions.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified 13 345 differentially expressed transcripts across the five time points (false discovery rate, <0.01) of which 58% were protein-coding genes. Two clusters of mainly downregulated genes represented cell cycle pathways and DNA repair. Upregulated genes showed one peak at 12 h that resembled the initiation of an inflammatory response, and one peak at 36 h that resembled the effector functions of inflammation such as vasodilation, angiogenesis, coagulation, chemotaxis and tissue remodelling. Genes involved in cell-matrix interactions as a part of cytoskeletal rearrangement and cell motility were also upregulated at 36 h. Predicted activated upstream regulators of ovulation included FSH, LH, transforming growth factor B1, tumour necrosis factor, nuclear factor kappa-light-chain-enhancer of activated B cells, coagulation factor 2, fibroblast growth factor 2, interleukin 1 and cortisol, among others. The results confirmed early regulation of several previously described factors in a cascade inducing meiotic resumption and suggested new factors involved in cumulus expansion and follicle rupture through co-regulation with previously described factors.

LARGE SCALE DATA

The microarray data were deposited to the Gene Expression Omnibus (www.ncbi.nlm.nih.gov/gds/, accession number: GSE133868).

LIMITATIONS, REASONS FOR CAUTION

The study included women undergoing ovarian stimulation and the findings may therefore differ from a natural cycle. However, the results confirm significant regulation of many well-established ovulatory genes from a series of previous studies such as amphiregulin, epiregulin, tumour necrosis factor alfa induced protein 6, tissue inhibitor of metallopeptidases 1 and plasminogen activator inhibitor 1, which support the relevance of the results.

WIDER IMPLICATIONS OF THE FINDINGS

The study increases our understanding of human ovarian function during ovulation, and the publicly available dataset is a valuable resource for future investigations. Suggested upstream regulators and highly differentially expressed genes may be potential pharmaceutical targets in fertility treatment and gynaecology.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by EU Interreg ÔKS V through ReproUnion (www.reprounion.eu) and by a grant from the Region Zealand Research Foundation. None of the authors have any conflicts of interest to declare.

Macrophages: an indispensable piece of ovarian health

Macrophages are the most abundant immune cells in the ovary. In addition to their roles in the innate immune system, these heterogeneous tissue-resident cells are responsive to tissue-derived signals, adapt to their local tissue environment, and specialize in unique functions to maintain tissue homeostasis. Research in the past decades has established a strong link between macrophages and various aspects of ovarian physiology, indicating a pivotal role of macrophages in ovarian health. However, unlike other intensively studied organs, the knowledge of ovarian macrophages dates back to the time when the heterogeneity of ontogeny, phenotype, and function of macrophages was not fully understood. In this review, we discuss the evolving understanding of the biology of ovarian tissue-resident macrophages, highlight their regulatory roles in normal ovarian functions, review the association between certain ovarian pathologies and disturbed macrophage homeostasis, and finally, discuss the technologies that are essential for addressing key questions in the field.

Neurotensin: a neuropeptide induced by hCG in the human and rat ovary during the periovulatory period†

Neurotensin (NTS) is a tridecapeptide that was first characterized as a neurotransmitter in neuronal cells. The present study examined ovarian NTS expression across the periovulatory period in the human and the rat. Women were recruited into this study and monitored by transvaginal ultrasound. The dominant follicle was surgically excised prior to the luteinizing hormone (LH) surge (preovulatory phase) or women were given 250 μg human chorionic gonadotropin (hCG) and dominant follicles collected 12-18 h after hCG (early ovulatory), 18-34 h (late ovulatory), and 44-70 h (postovulatory). NTS mRNA was massively induced during the early and late ovulatory stage in granulosa cells (GCs) (15 000 fold) and theca cells (700 fold). In the rat, hCG also induced Nts mRNA expression in intact ovaries and isolated GCs. In cultured granulosa-luteal cells (GLCs) from IVF patients, NTS expression was induced 6 h after hCG treatment, whereas in cultured rat GCs, NTS increased 4 h after hCG treatment. Cells treated with hCG signaling pathway inhibitors revealed that NTS expression is partially regulated in the human and rat GC by the epidermal-like growth factor pathway. Human GLC, and rat GCs also showed that Nts was regulated by the protein kinase A (PKA) pathway along with input from the phosphotidylinositol 3- kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways. The predominat NTS receptor present in human and rat GCs was SORT1, whereas NTSR1 and NTSR2 expression was very low. Based on NTS actions in other systems, we speculate that NTS may regulate crucial aspects of ovulation such as vascular permeability, inflammation, and cell migration.

Ovulation is Inhibited by an Environmentally Relevant Phthalate Mixture in Mouse Antral Follicles In Vitro

Phthalates are solvents and plasticizers found in consumer products including cosmetics, food/beverage containers, housing materials, etc. Phthalates are known endocrine-disrupting chemicals that can directly target the ovary, potentially causing defects in ovulation and fertility. Women are exposed to multiple different phthalates daily, therefore this study investigated the effects of an environmentally relevant phthalate mixture (PHTmix) on ovulation. Ovulation is initiated by the luteinizing hormone (LH) surge, which induces prostaglandin (PG) production, progesterone (P4)/progesterone receptor (PGR) signaling, and extracellular matrix (ECM) remodeling. We hypothesized that the PHTmix would directly inhibit ovulation by altering the levels of PGs, P4/PGR, and enzymes involved in ECM remodeling. Antral follicles from CD-1 mice were treated with vehicle control alone (dimethylsulfoxide, DMSO), hCG alone (LH analog), and hCG+PHTmix (1-500μg/ml), and samples were collected across the ovulatory period. The PHTmix decreased ovulation rates at all doses tested in a dose-dependent manner when compared to hCG. PG levels were decreased by the PHTmix when compared to hCG, which was potentially mediated by altered levels of PG synthesis (Ptgs2) and transport (Slco2a1) genes. The PHTmix altered P4 and Pgr levels when compared to hCG, leading to decreases in downstream PGR-mediated genes (Edn2, Il6, Adamts1). ECM remodeling was potentially dysregulated by altered levels of ovulatory mediators belonging to the matrix metalloproteases and plasminogen activator families. These data suggest that phthalate exposure inhibits ovulation by altering PG levels, P4/PGR action, and ECM remodeling.

Harmful and beneficial effects of inflammatory response on reproduction: sterile and pathogen-associated inflammation

In reproduction, inflammatory processes play important roles in the development of many pregnancy complications such as preterm labor/birth, recurrent pregnancy loss, recurrent implantation failure, and preeclampsia. Inflammation can be initiated by both microbial and non-microbial causes. Bacterial infection in the feto-maternal interface and uterus can provoke preterm labor/birth, miscarriage, and chronic endometritis. By contrast, inflammation without infection, or 'sterile inflammation,' can also lead to many kinds of complications, such as preterm labor/birth, miscarriage, or preeclampsia. Aberrant inflammation is facilitated by immune cells such as macrophages, dendritic cells, natural killer cells, and invariant natural killer T cells. In addition, cytokines, chemokines, and several kinds of inflammatory mediators are involved. On the other hand, appropriate inflammation is required for a successful offspring during the progression of the entire pregnancy. Herein, we discuss the relation between pregnancy and inflammation with immunological alterations. Understanding the role of inflammation in complications during pregnancy may establish new perspectives of the progress of normal pregnancy as well as treatments during pregnancy complications.

Granulosa cell proliferation is inhibited by PGE2 in the primate ovulatory follicle

Prostaglandin E2 (PGE2) is a key paracrine mediator of ovulation. Few specific PGE2-regulated gene products have been identified, so we hypothesized that PGE2 may regulate the expression and/or activity of a network of proteins to promote ovulation. To test this concept, Ingenuity Pathway Analysis (IPA) was used to predict PGE2-regulated functionalities in the primate ovulatory follicle. Cynomolgus macaques underwent ovarian stimulation. Follicular granulosa cells were obtained before (0 h) or 36 h after an ovulatory dose of human chorionic gonadotropin (hCG), with ovulation anticipated 37–40 h after hCG. Granulosa cells were obtained from additional monkeys 36 h after treatment with hCG and the PTGS2 inhibitor celecoxib, which significantly reduced hCG-stimulated follicular prostaglandin synthesis. Granulosa cell RNA expression was determined by microarray and analyzed using IPA. No granulosa cell mRNAs were identified as being significantly up-regulated or down-regulated by hCG + celecoxib compared with hCG only. However, IPA predicted that prostaglandin depletion significantly regulated several functional pathways. Cell cycle/cell proliferation was selected for further study because decreased granulosa cell proliferation is known to be necessary for ovulation and formation of a fully-functional corpus luteum. Prospective in vivo and in vitro experiments confirmed the prediction that hCG-stimulated cessation of granulosa cell proliferation is mediated via PGE2. Our studies indicate that PGE2 provides critical regulation of granulosa cell proliferation through mechanisms that do not involve significant regulation of mRNA levels of key cell cycle regulators. Pathway analysis correctly predicted that PGE2 serves as a paracrine mediator of this important transition in ovarian structure and function.

Human Chorionic Gonadotropin-Mediated Immune Responses That Facilitate Embryo Implantation and Placentation

Human chorionic gonadotropin (hCG) serves as one of the first signals provided by the embryo to the mother. Exactly at the time when the first step of the implantation process is initiated and the blastocyst adheres to the maternal endometrium, the embryonic tissue starts to actively secrete hCG. Shortly thereafter, the hormone can be detected in the maternal circulation where its concentration steadily increases throughout early pregnancy as it is continuously released by the forming placenta. Accumulating evidence underlines the critical function of hCG for embryo implantation and placentation. hCG not only regulates biological aspects of these early pregnancy events but also supports maternal immune cells in their function as helpers in the establishment of an adequate embryo-endometrial relationship. In view of its early presence in the maternal circulation, hCG has the potential to influence both local uterine immune cell populations as well as peripheral ones. The current review aims to summarize recent literature on the participation of innate and adaptive immune cells in embryo implantation and placentation with a specific focus on their regulation by hCG.

The endogenous hydrogen sulfide generating system regulates ovulation

The generation of free-radicals such as nitric oxide has been implicated in the regulation of ovarian function, including ovulation. Tissues that generate nitric oxide typically generate another free-radical gas, hydrogen sulfide (H₂S), although little is known about the role of H₂S in ovarian function. The hypothesis of this study was that H₂S regulates ovulation. Treatment with luteinizing hormone (LH) increased the levels of mRNA and protein of the H₂S generating enzyme cystathionine γ-lyase (CTH) in granulosa cells of mice and humans in vivo and in vitro. Pharmacological inhibition of H₂S generating enzymes reduced the number of follicles ovulating in mice in vivo and in vitro, and this inhibitory action was reversed by cotreatment with a H₂S donor. Addition of a H₂S donor to cultured mouse granulosa cells increased basal and LH-dependent abundance of mRNA encoding amphiregulin, betacellulin and tumor necrosis alpha induced protein 6, proteins important for cumulus expansion and follicle rupture. Inhibition of CTH activity reduced abundance of mRNA encoding matrix metalloproteinase-2 and -9 and tissue-type plasminogen activator, and cotreatment with the H₂S donor increased the levels of these mRNA above those stimulated by LH alone. We conclude that the H₂S generating system plays an important role in the propagation of the preovulatory cascade and rupture of the follicle at ovulation.

Genetic Diversity of Indigenous Pigs from South China Area Revealed by SNP Array

Simple Summary

The pig is one of the most important livestock animals, providing the majority of protein for humans. The population genetics analysis of pigs not only helps humans understand the domestication of the pig but also helps breeders in the genetic improvement of pigs. In this study, the population genetics of 11 pig breeds of South China were analyzed with the help of single nucleotide polymorphism (SNP) chips. The results showed that the genetic diversity of South China indigenous pigs is declining rapidly, and gene introgression from commercial pigs to indigenous pigs was detected. Selection signature analysis showed differences among South China indigenous pig breeds, commercial pig breeds, and wild pig breeds were present for meat quality and growth. Our study deepened understanding of the conservation status and selection mechanisms of Chinese indigenous pigs.

Abstract

To investigate the genetic diversity, population structure, extent of linkage disequilibrium (LD), effective population size (Ne), and selection signatures in indigenous pigs from Guangdong and Guangxi in China, 226 pigs belonging to ten diverse populations were genotyped using single nucleotide polymorphism (SNP) chips. The genetic divergence between Chinese and Western pigs was determined based on the SNP chip data. Low genetic diversity of Dahuabai (DHB), Luchuan (LC), Lantang (LT), and Meihua (MH) pigs, and introgression of Western pigs into Longlin (LL), MH, and Yuedonghei (YDH) pigs were detected. Analysis of the extent of LD showed that indigenous pigs had low LD when pairwise SNP distance was short and high LD when pairwise SNP distance was long. Effective population size analysis showed a rapid decrease for Chinese indigenous pigs, and some pig populations had a relatively small Ne. This result indicated the loss of genetic diversity in indigenous pigs, and introgression from Western commercial pigs. Selection signatures detected in this study overlapped with meat quality traits, such as drip loss, intramuscular fat content, meat color b*, and average backfat thickness. Our study deepened understanding of the conservation status and domestication of Chinese indigenous pigs.

Human granulosa cells function as innate immune cells executing an inflammatory reaction during ovulation: a microarray analysis

Ovulation has been compared to a local inflammatory reaction. We performed an in silico study on a unique, PCR validated, transcriptome microarray study to evaluate if known inflammatory mechanisms operate during ovulation. The granulosa cells were obtained in paired samples at two different time points during ovulation (just before and 36 hours after ovulation induction) from nine women receiving fertility treatment. A total of 259 genes related to inflammation became significantly upregulated during ovulation (2-80 fold, p<0.05), while specific leukocyte markers were absent. The genes and pathway analysis indicated NF-KB-, MAPK- and JAK/STAT signalling (p<1.0E-10) as the major pathways involved in danger recognition and cytokine signalling to initiate inflammation. Upregulated genes further encoded enzymes in eicosanoid production, chemo-attractants, coagulation factors, cell proliferation factors involved in tissue repair, and anti-inflammatory factors to resolve the inflammation again. We conclude that granulosa cells, without involvement from the innate immune system, can orchestrate ovulation as a complete sterile inflammatory reaction.

Ovulation: Parallels With Inflammatory Processes

The midcycle surge of LH sets in motion interconnected networks of signaling cascades to bring about rupture of the follicle and release of the oocyte during ovulation. Many mediators of these LH-induced signaling cascades are associated with inflammation, leading to the postulate that ovulation is similar to an inflammatory response. First responders to the LH surge are granulosa and theca cells, which produce steroids, prostaglandins, chemokines, and cytokines, which are also mediators of inflammatory processes. These mediators, in turn, activate both nonimmune ovarian cells as well as resident immune cells within the ovary; additional immune cells are also attracted to the ovary. Collectively, these cells regulate proteolytic pathways to reorganize the follicular stroma, disrupt the granulosa cell basal lamina, and facilitate invasion of vascular endothelial cells. LH-induced mediators initiate cumulus expansion and cumulus oocyte complex detachment, whereas the follicular apex undergoes extensive extracellular matrix remodeling and a loss of the surface epithelium. The remainder of the follicle undergoes rapid angiogenesis and functional differentiation of granulosa and theca cells. Ultimately, these functional and structural changes culminate in follicular rupture and oocyte release. Throughout the ovulatory process, the importance of inflammatory responses is highlighted by the commonalities and similarities between many of these events associated with ovulation and inflammation. However, ovulation includes processes that are distinct from inflammation, such as regulation of steroid action, oocyte maturation, and the eventual release of the oocyte. This review focuses on the commonalities between inflammatory responses and the process of ovulation.

An optimized model for hCG stimulation of human mural granulosa cell culture

Ovarian follicular development and ovulation in mammals is a highly-regulated process. Most of the current knowledge of ovarian processes was obtained from the studies of non-human models. Molecular studies on human ovarian processes suffer from lack of material and appropriate research tools. Mural granulosa cells (MGCs) culture is a major tool for studying the effect of different substances but a major problem for using these primary MGCs is their unresponsiveness to hCG stimulation at the time of oocyte retrieval. It is acceptable that MGCs regain responsiveness during days in culture but when the best time is and how to accelerate the regenerative process are unknown. The aim of the current study was to establish an optimized protocol which will provide a practical and efficient tool to examine the effect of LH/hCG on different downstream targets in luteinized MGCs. hCG effects were examined according to days in culture and hCG stimulation time. As read-out, we analyzed the gene expression of known hCG targets, protein production, and progesterone secretion. Our results show that with a daily medium exchange, the strongest effect was achieved already 4 days after seeding. On day 4, hCG stimulation triggers two major patterns of gene expression. Early induced genes were highly expressed 6-8 h after hCG, while 24 h of hCG stimulation was needed for late induced genes. Based on our results, we suggest daily medium exchange for 4 days before adding hCG and examine its effect 6 and 24 h later.

FOS, a Critical Downstream Mediator of PGR and EGF Signaling Necessary for Ovulatory Prostaglandins in the Human Ovary

Context

Fos null mice failed to ovulate and form a corpus luteum (CL) even when given exogenous gonadotropins, suggesting that ovarian Fos expression is critical for successful ovulation and CL formation. However, little is known about FOS in the human ovary.

Objectives

To determine the expression, regulation, and function of FOS in human periovulatory follicles.

Design/Participants

Timed periovulatory follicles were obtained from normally cycling women. Granulosa/lutein cells were collected from in vitro fertilization patients.

Main Outcome Measures

The in vivo expression after human chorionic gonadotropin (hCG) administration and in vitro regulation of FOS, JUN, JUNB, and JUND was evaluated at the mRNA and protein level. Binding of progesterone receptor (PGR) and FOS to their target genes was assessed by chromatin immunoprecipitation analyses. Prostaglandin E2 (PGE2) and progesterone were measured.

Results

The expression of FOS, JUNB, and JUND drastically increased in ovulatory follicles after hCG administration. In human granulosa/lutein cell cultures, hCG increased the expression of FOS and JUN proteins. Inhibitors of PGR and epidermal growth factor (EGF) receptors reduced hCG-induced increases in the expression and phosphorylation of FOS. PGR bound to the FOS gene. A selective FOS inhibitor blocked hCG-induced increases in PGE2 and the expression of prostaglandin (PG) synthases and transporters (PTGES, SLCO2A1, and ABCC1). FOS bound to the promoter regions of these genes.

Conclusions

The increase of FOS/activator protein 1 in human periovulatory follicles after hCG administration is mediated by collaborative actions of PGR and EGF signaling and critical for the upregulated expression of key ovulatory genes required for the rise in ovulatory PG in human granulosa cells.

Ovulatory Induction of SCG2 in Human, Nonhuman Primate, and Rodent Granulosa Cells Stimulates Ovarian Angiogenesis

The luteinizing hormone (LH) surge is essential for ovulation, but the intrafollicular factors induced by LH that mediate ovulatory processes (e.g., angiogenesis) are poorly understood, especially in women. The role of secretogranin II (SCG2) and its cleaved bioactive peptide, secretoneurin (SN), were investigated as potential mediators of ovulation by testing the hypothesis that SCG2/SN is induced in granulosa cells by human chorionic gonadotropin (hCG), via a downstream LH receptor signaling mechanism, and stimulates ovarian angiogenesis. Humans, nonhuman primates, and rodents were treated with hCG in vivo resulting in a significant increase in the messenger RNA and protein levels of SCG2 in granulosa cells collected early during the periovulatory period and just prior to ovulation (humans: 12 to 34 hours; monkeys: 12 to 36 hours; rodents: 4 to 12 hours post-hCG). This induction by hCG was recapitulated in an in vitro culture system utilizing granulosa-lutein cells from in vitro fertilization patients. Using this system, inhibition of downstream LH receptor signaling pathways revealed that the initial induction of SCG2 is regulated, in part, by epidermal growth factor receptor signaling. Further, human ovarian microvascular endothelial cells were treated with SN (1 to 100 ng/mL) and subjected to angiogenesis assays. SN significantly increased endothelial cell migration and new sprout formation, suggesting induction of ovarian angiogenesis. These results establish that SCG2 is increased in granulosa cells across species during the periovulatory period and that SN may mediate ovulatory angiogenesis in the human ovary. These findings provide insight into the regulation of human ovulation and fertility.

The expression of CXCR4 is induced by the luteinizing hormone surge and mediated by progesterone receptors in human preovulatory granulosa cells

The chemokine CXC motif ligand 12 (CXCL12) and its cognate receptor, CXCR4, have been implicated in the ovulatory process in various animal models. However, little is known about the expression and regulation of CXCL12 and CXCR4 and their functions during the ovulatory period in the human ovary. In this study, we characterized the expression patterns of CXCL12 and CXCR4 in preovulatory follicles collected before the luteinizing hormone (LH) surge and at defined hours after hCG administration in women with the regular menstrual cycle. The levels of mRNA and protein for CXCR4 were increased in granulosa cells of late ovulatory follicles, whereas CXCL12 expression was constant in follicles throughout the ovulatory period. Both CXCR4 and CXCL12 were localized to a subset of leukocytes around and inside the vasculature of human preovulatory follicles. Using a human granulosa cell culture model, the regulatory mechanisms and functions of CXCL12 and CXCR4 expression were investigated. Human chorionic gonadotropin (hCG) stimulated CXCR4 expression, whereas CXCL12 expression was not affected, mimicking in vivo expression patterns. Both RU486 (progesterone receptor antagonist) and CoCl2 (HIFs activator) blocked the hCG-induced increase in CXCR4 expression, whereas AG1478 (EGFR inhibitor) had no effect. The treatment with CXCL12 had no effect on granulosa cell viability but decreased hCG-stimulated CXCR4 expression.

The Ovarian Cycle

The "ovarian cycle" is an exquisite and dynamic endocrine system that includes ovarian events, hypothalamic-pituitary interactions, uterine endometrial and myometrial changes during implantation and pregnancy, cervical alterations in structure, and breast development. The ovarian cycle and the steroid hormones produced by the ovary also impact epithelial cancer development in the ovary, uterus, cervix, and breast. This chapter provides a personal view of recent developments that occur in this complex endocrine environment.

Ovarian Follicular Theca Cell Recruitment, Differentiation, and Impact on Fertility: 2017 Update

The major goal of this review is to summarize recent exciting findings that have been published within the past 10 years that, to our knowledge, have not been presented in detail in previous reviews and that may impact altered follicular development in polycystic ovarian syndrome (PCOS) and premature ovarian failure in women. Specifically, we will cover the following: (1) mouse models that have led to discovery of the derivation of two precursor populations of theca cells in the embryonic gonad; (2) the key roles of the oocyte-derived factor growth differentiation factor 9 on the hedgehog (HH) signaling pathway and theca cell functions; and (3) the impact of the HH pathway on both the specification of theca endocrine cells and theca fibroblast and smooth muscle cells in developing follicles. We will also discuss the following: (1) other signaling pathways that impact the differentiation of theca cells, not only luteinizing hormone but also insulinlike 3, bone morphogenic proteins, the circadian clock genes, androgens, and estrogens; and (2) theca-associated vascular, immune, and fibroblast cells, as well as the cytokines and matrix factors that play key roles in follicle growth. Lastly, we will integrate what is known about theca cells from mouse models, human-derived theca cell lines from patients who have PCOS and patients who do not have PCOS, and microarray analyses of human and bovine theca to understand what pathways and factors contribute to follicle growth as well as to the abnormal function of theca.

Detection of dendritic cells and related cytokines in follicular fluid of patients with polycystic ovary syndrome

PROBLEM

The presence of dendritic cells (DCs) and associated cytokines in follicular fluid (FF) from patients with polycystic ovary syndrome (PCOS) remains unknown.

METHODS OF STUDY

FF was collected from PCOS patients and patients with severe male factor infertility (control) at the day of transvaginal oocyte retrieval. Phenotypes of DC were detected by flow cytometry, and TNF-α, IL-6, IL-10, and IL-23 were assessed by ELISA.

RESULTS

A significant decrease in the percentage of DC was found in patients with PCOS (16.22±5.5%) compared with control (21.27±5.5%, P<.01). E₂ on the day of hCG administration was correlated positively with the mean fluorescence intensity of HLA-DR (r=.75, P<.01) and reversely correlated with the concentration of TNF-α in FF (r=-.69, P<.01). The level of TNF-α, IL-6, and IL-10 increased significantly but IL-23 decreased in FF from patients with PCOS.

CONCLUSION

The decrease of DC and disturbance of associated cytokines in FF from PCOS patients indicates a disorder of immunological microenvironment of the ovarian follicle, which might be involved in the dysfunction of folliculogenesis.

Coordinated Regulation Among Progesterone, Prostaglandins, and EGF-Like Factors in Human Ovulatory Follicles

CONTEXT

In animal models, the luteinizing hormone surge increases progesterone (P4) and progesterone receptor (PGR), prostaglandins (PTGs), and epidermal growth factor (EGF)-like factors that play essential roles in ovulation. However, little is known about the expression, regulation, and function of these key ovulatory mediators in humans.

OBJECTIVE

To determine when and how these key ovulatory mediators are induced after the luteinizing hormone surge in human ovaries.

DESIGN AND PARTICIPANTS

Timed periovulatory follicles were obtained from cycling women. Granulosa/lutein cells were collected from in vitro fertilization patients.

MAIN OUTCOME MEASURES

The in vivo and in vitro expression of PGR, PTG synthases and transporters, and EGF-like factors were examined at the level of messenger RNA and protein. PGR binding to specific genes was assessed. P4 and PTGs in conditioned media were measured.

RESULTS

PGR, PTGS2, and AREG expressions dramatically increased in ovulatory follicles at 12 to 18 hours after human chorionic gonadotropin (hCG). In human granulosa/lutein cell cultures, hCG increased P4 and PTG production and the expression of PGR, specific PTG synthases and transporters, and EGF-like factors, mimicking in vivo expression patterns. Inhibitors for P4/PGR and EGF-signaling pathways reduced hCG-induced increases in PTG production and the expression of EGF-like factors. PGR bound to the PTGS2, PTGES, and SLCO2A1 genes.

CONCLUSIONS

This report demonstrated the time-dependent induction of PGR, AREG, and PTGS2 in human periovulatory follicles. In vitro studies indicated that collaborative actions of P4/PGR and EGF signaling are required for hCG-induced increases in PTG production and potentiation of EGF signaling in human periovulatory granulosa cells.

Regulation of interleukin-11 expression in ovulatory follicles of the rat ovary

The aim of the present study was to examine the regulation of interleukin (IL)-11 expression, as well as the role of IL-11, during ovulation in gonadotropin-primed immature rats. Injection of equine chorionic gonadotropin (eCG), followed by human CG (hCG) to induce superovulation stimulated expression of the Il11 gene in theca cells within 6 h, as revealed by northern blot and in situ hybridisation analyses. Real-time reverse transcription–polymerase chain reaction analysis showed that the IL-11 receptor, α subunit gene was expressed in granulosa and theca cells and that injection of hCG had no effect on its expression. IL-11 protein expression was stimulated in theca cells by hCG. LH-stimulated increases in Il11 mRNA levels in cultured preovulatory follicles were inhibited by protein kinase A and mitogen-activated protein kinase kinase inhibitors. Toll-like receptor (TLR) 2 and TLR4 were detected in preovulatory follicles, and the TLR4 ligand lipopolysaccharide, but not the TLR2 ligand Pam3Cys, increased Il11 mRNA levels in theca cells, but not in granulosa cells. Treatment of preovulatory follicles with IL-11 stimulated progesterone production and steroidogenic acute regulatory protein (Star) gene expression. Together, these results indicate that IL-11 in theca cells is stimulated by mitogen-activated protein kinase signalling and TLR4 activation, and increases progesterone production during ovulation.

Enhanced Inflammatory Transcriptome in the Granulosa Cells of Women With Polycystic Ovarian Syndrome

CONTEXT

Polycystic ovarian syndrome (PCOS), the most common endocrine disorder of reproductive-aged women, is associated with systemic low-grade inflammation.

OBJECTIVE

We propose that increased or altered intrafollicular inflammatory reactions also occur in periovulatory follicles of PCOS patients.

DESIGN

Gene profiling and quantitative PCR (qPCR) analyses in granulosa-lutein cells (GCs) collected from PCOS and non-PCOS women undergoing in vitro fertilization were compared with serum and follicular fluid (FF) levels of cytokines and chemokines.

SETTING

This was a university-based study.

PATIENTS

Twenty-one PCOS and 45 control patients were recruited: demographic, hormone, body mass index, and pregnancy outcomes were abstracted from patient data files.

INTERVENTIONS

GC cytokine/chemokine mRNAs were identified and analyzed by gene-chip microarrays/qPCR before and after culture with human chorionic gonadotropin, DHT, IL-6, or IL-8; serum/FF cytokine levels were also analyzed.

MAIN OUTCOME MEASURES

Relative serum/FF cytokine levels and GC cytokine expression before and after culture were compared and related to body mass index.

RESULTS

The following results were found: 1) PCOS GCs express elevated transcripts encoding cytokines, chemokines, and immune cell markers, 2) based on gene profiling and qPCR analyses, obese PCOS patients define a distinct PCOS disease subtype with the most dramatic increases in proinflammatory and immune-related factors, and 3) human chorionic gonadotropin and DHT increased cytokine production in cultured GCs, whereas cytokines augmented cytokine and vascular genes, indicating that hyperandrogenism/elevated LH and obesity in PCOS women augment intrafollicular cytokine production.

CONCLUSIONS

Intrafollicular androgens and cytokines likely comprise a local regulatory loop that impacts GC expression of cytokines and chemokines and the presence of immune cells; this loop is further enhanced in the obese PCOS subtype.