The Chemokine SDF-1/CXCL12 Contributes to T Lymphocyte Recruitment in Human Pre-ovulatory Follicles and Coordinates with Lymphocytes to Increase Granulosa Cell Survival and Embryo Quality

Disturbed Follicular Microenvironment in Polycystic Ovary Syndrome: Relationship to Oocyte Quality and Infertility

Polycystic ovary syndrome (PCOS) is a common endocrine disorder associated with infertility and poor reproductive outcomes. The follicular fluid (FF) microenvironment plays a crucial role in oocyte development. This review summarizes evidence elucidating the alterations in FF composition in PCOS. Various studies demonstrated a pronounced proinflammatory milieu in PCOS FF, characterized by increased levels of cytokines, including but not limited to interleukin-6 (IL-6), tumor necrosis factor α, C-reactive protein, and IL-1β, concomitant with a reduction in anti-inflammatory IL-10. T lymphocytes and antigen-presenting cells are dysregulated in PCOS FF. PCOS FF exhibit heightened reactive oxygen species production and the accumulation of lipid peroxidation byproducts, and impaired antioxidant defenses. Multiple microRNAs are dysregulated in PCOS FF, disrupting signaling critical to granulosa cell function. Proteomic analysis reveals changes in pathways related to immune responses, metabolic perturbations, angiogenesis, and hormone regulation. Metabolomics identify disturbances in glucose metabolism, amino acids, lipid profiles, and steroid levels with PCOS FF. Collectively, these pathological alterations may adversely affect oocyte quality, embryo development, and fertility outcomes. Further research on larger cohorts is needed to validate these findings and to forge the development of prognostic biomarkers of oocyte developmental competence within FF. Characterizing the follicular environment in PCOS is key to elucidating the mechanisms underlying subfertility in this challenging disorder.

Roles of immune microenvironment in the female reproductive maintenance and regulation: novel insights into the crosstalk of immune cells

Female fertility decline is an accumulative consequence caused by complex factors, among them, the disruption of the immune profile in female reproduction stands out as a crucial contributor. Presently, the effects of immune microenvironment (IME) on the female reproductive process have attracted increasing attentions for their dynamic but precisive roles. Immunocytes including macrophages, dendritic cells, T cells, B cells and neutrophils, with diverse subpopulations as well as high plasticity functioned dynamically in the process of female reproduction through indirect intercellular communication via specific cytokine release transduced by molecular signal networks or direct cell-cell contact to maintain the stability of the reproductive process have been unveiled. The immune profile of female reproduction in each stage has also been meticulously unveiled. Especially, the application of single-cell sequencing (scRNA-seq) technology in this process reveals the distribution map of immune cells, which gives a novel insight for the homeostasis of IME and provides a research direction for better exploring the role of immune cells in female reproduction. Here, we provide an all-encompassing overview of the latest advancements in immune modulation within the context of the female reproductive process. Our approach involves structuring our summary in accordance with the physiological sequence encompassing gonadogenesis, folliculogenesis within the ovaries, ovulation through the fallopian tubes, and the subsequent stages of embryo implantation and development within the uterus. Our overarching objective is to construct a comprehensive portrayal of the immune microenvironment (IME), thereby accentuating the pivotal role played by immune cells in governing the intricate female reproductive journey. Additionally, we emphasize the pressing need for heightened attention directed towards strategies that focus on immune interventions within the female reproductive process, with the ultimate aim of enhancing female fertility.

Poor ovarian response in assisted reproductive technology cycles is associated with anti-ovarian antibody and pro-inflammatory immune responses

Anti-ovarian antibody (AOA) could be considered an independent marker for autoimmune ovarian disease and predicting future premature ovarian failure (POF). This study aims to investigate if AOA is associated with poor ovarian response (POR) and pro-inflammatory immune responses in women undergoing assisted reproductive technology (ART) cycles. Two hundred forty-eight women undergoing ART cycles were divided into four groups based on AOA test results and the presence of POR: POR(-)/AOA(-) group (N = 148), POR(+)/AOA(-) group (N = 34), POR (-)/AOA(+) group (N = 44), POR(+)/AOA(+) group (N = 22). The POR patients have a significantly higher prevalence of AOA than non-POR patients (P < 0.05). Peripheral blood CD56 + natural killer (NK) cell level (%), NK cytotoxicity, CD19 +CD5 + B-1 cell level (%), and IFN-γ/IL-10 producing T helper (Th) 1/Th2 cell ratios were significantly higher in POR(+)/AOA(+) group than those of other groups (P < 0.001, P < 0.005, P < 0.01, P < 0.05, respectively). TNF-α/IL-10 producing Th1/Th2 cell ratio of POR(+)/AOA(+) group was significantly higher than those of POR(+)/AOA(-) and POR(-)/AOA(-) groups (P < 0.05, respectively). Homocysteine and vitamin D levels of the POR(+)/AOA(+) group were significantly lower than those of other groups (P < 0.005, respectively). Plasminogen activator inhibiter-1 (PAI-1) level of POR(+)/AOA(+) group was significantly higher than that of POR(-)/AOA(-) group (P < 0.05). In the POR(+)/AOA(+) group, the prevalence of antiphospholipid antibodies was significantly higher than that of the POR(+)/AOA(-) group (P = 0.005). Women with autoimmune POR (POR(+)/AOA(+)) have dysregulated pro-inflammatory immune responses and metabolic factors. The diagnostic and therapeutic approaches for autoimmune POR should be differentiated from those for non-autoimmune POR.

Association between immunity and different clinical symptoms in patients with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a disease with endocrine and metabolic disorders. The main symptoms are hyperandrogenemia (HA), insulin resistance (IR), and ovulation disorder. However, the pathogenesis and pathophysiological process of these major symptoms in PCOS are still not well defined. In recent studies, the chronic low-grade inflammatory state has become one of the factors affecting PCOS. Some alterable immune factors in PCOS, such as interleukin-15 and interleukin-1, have been identified to be related to androgen synthesis and insulin resistance in PCOS. In addition, a disturbed immune microenvironment in the ovary leads to impaired follicular growth and ovulation. Previous studies have roughly reviewed the relationship between immunity and PCOS. However, the link between the different clinical manifestations of PCOS and immunity has not been well explored and analyzed. The clinical presentation of each patient is diverse, and symptomatic treatment is mainly used. Therefore, this article reviews several representative immunological factors that affect these three symptoms to explore the underlying mechanism, which will be beneficial for developing new treatment strategies.

Ethnic disparities in the immune microenvironment of triple negative breast cancer and its role in therapeutic outcomes

In 2020, newly diagnosed breast cancer (BC) cases surpassed that of lung cancer among women, making it the most common female cancer globally. In spite of recent increases in incidence rates, mortality due to BC has declined since 1989. These declines have been attributed to advancements in treatment modalities as well as increased mammography surveillance. Despite these advances, African American (AA) women are 40% more likely to die from BC than Caucasian women. Multifactorial etiology has been implicated in the disparity of BC mortality rates among AA women. As an example, AA women have a disproportionate incidence of triple negative breast cancer (TNBC), which has a poor prognosis and marginal treatment options. Increasingly, the tumor microenvironment (TME) has gained relevance as it relates to primary tumor progression, metastasis and treatment possibilities. The treatment outcomes or pathological complete response (pCR) in TNBC among AA women are affected by differences in TME. The TME of AA women exhibit several variances in acellular and cellular components associated with pro-tumorigenic effects. For example, increased levels of the adipocyte-related hormone, resistin, the pro-inflammatory cytokine, IL-6, and the CC chemokine, CCL2, within the TME of AA women gives rise to an increased density of M2 macrophages, also known as tumor-associated macrophages. Elevated levels of vascular endothelial growth factor in the TME of AA women increase the vascular density or vascularity, which facilitate aggressive tumor growth and metastasis. Furthermore, a pro-tumorigenic TME is supported by increased levels of the CXC chemokine, CXCL12 that results in the recruitment of regulatory T lymphocytes (Tregs ). Due to these and other differences in the TME of AA women, precision oncology can target specific aspects of the TME that may contribute to a poorer prognosis. In addition to the discrepancies in the TME, AA women face socio-economic barriers that limit their ability to access state-of-the-art, novel therapies against metastatic TNBC. In this review, we will provide a brief overview of the tumor immune microenvironment, immune-based treatment options for TNBC and their potential to decrease health disparities due to ethnicity.

Dysregulation of immune response in PCOS organ system

Polycystic ovary syndrome (PCOS) is the most common reproductive endocrine disorder affecting women, which can lead to infertility. Infertility, obesity, hirsutism, acne, and irregular menstruation are just a few of the issues that PCOS can be linked to. PCOS has a complicated pathophysiology and a range of clinical symptoms. Chronic low-grade inflammation is one of the features of PCOS. The inflammatory environment involves immune and metabolic disturbances. Numerous organ systems across the body, in addition to the female reproductive system, have been affected by the pathogenic role of immunological dysregulation in PCOS in recent years. Insulin resistance and hyperandrogenism are associated with immune cell dysfunction and cytokine imbalance. More importantly, obesity is also involved in immune dysfunction in PCOS, leading to an inflammatory environment in women with PCOS. Hormone, obesity, and metabolic interactions contribute to the pathogenesis of PCOS. Hormone imbalance may also contribute to the development of autoimmune diseases. The aim of this review is to summarize the pathophysiological role of immune dysregulation in various organ systems of PCOS patients and provide new ideas for systemic treatment of PCOS in the future.

Immune Dysfunction in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-aged individuals with ovaries. It is associated with anovulation and increased risk to fertility and metabolic, cardiovascular, and psychological health. The pathophysiology of PCOS is still inadequately understood, although there is evidence of persistent low-grade inflammation, which correlates with associated visceral obesity. Elevated proinflammatory cytokine markers and altered immune cells have been reported in PCOS and raise the possibility that immune factors contribute to ovulatory dysfunction. Because normal ovulation is modulated by immune cells and cytokines in the ovarian microenvironment, the endocrine and metabolic abnormalities associated with PCOS orchestrate the accompanying adverse effects on ovulation and implantation. This review evaluates the current literature on the relationship between PCOS and immune abnormalities, with a focus on emerging research in the field.

Global gene expression analysis of the turkey hen hypothalamo-pituitary-gonadal axis during the preovulatory hormonal surge

The preovulatory hormonal surge (PS) consists of elevated circulating luteinizing hormone (LH) and progesterone levels and serves as the primary trigger for ovarian follicle ovulation. Increased LH and progesterone, produced by the pituitary and the granulosa layer of the largest ovarian follicle (F1), respectively, result from hypothalamic stimulation and steroid hormone feedback on the hypothalamo-pituitary-gonadal (HPG) axis. The hypothalamus, pituitary, F1 granulosa, and granulosa layer of the fifth largest follicle (F5) were isolated from converter turkey hens outside and during the PS and subjected to RNA sequencing (n = 6 per tissue). Differentially expressed genes were subjected to functional annotation using DAVID and IPA. A total of 12, 250, 1235, and 1938 DEGs were identified in the hypothalamus, pituitary, F1 granulosa, and F5 granulosa respectively (q<0.05, |fold change|>1.5, FPKM>1). Gene Ontology (GO) analysis revealed key roles for metabolic processes, steroid hormone feedback, and hypoxia induced gene expression changes. Upstream analysis identified a total of 4, 42, 126, and 393 potential regulators of downstream gene expression in the hypothalamus, pituitary, F1G, and F5G respectively, with a total of 63 potential regulators exhibiting differential expression between samples collected outside and during the PS (|z-score|>2). The results from this study serve to increase the current knowledge base surrounding the regulation of the PS in turkey hens. Through GO analysis, downstream processes and functions associated with the PS were linked to identified DEGs, and through upstream analysis, potential regulators of DEGs were identified for further analysis. Linking upstream regulators to the downstream PS and ovulation events could allow for genetic selection or manipulation of ovulation frequencies in turkey hens.

Endocrine and molecular factors of increased female reproductive performance in the Dummerstorf high-fertility mouse line FL1

The Dummerstorf high-fertility mouse line FL1 is a worldwide unique selection experiment for increased female reproductive performance. After more than 190 generations of selection, these mice doubled the amount of offspring per litter compared to the unselected control line. FL1 females have a superior lifetime fecundity and the highest Silver fecundity index that has been described in mice, while their offspring show no signs of growth retardation. The reasons for the increased reproductive performance remained unclear. Thus, this study aims to characterize the Dummerstorf high-fertility mouse line FL1 on endocrine and molecular levels on the female side. We analyzed parameters of the hypothalamic pituitary gonadal axis on both hormonal and transcriptional levels. Gonadotropin-releasing hormone and follicle-stimulating hormone (FSH) concentrations were decreased in FL1 throughout the whole estrous cycle. Luteinizing hormone (LH) was increased in FL1 mice in estrus. Progesterone concentrations were decreased in estrus in FL1 mice and not affected in diestrus. We used a holistic gene expression approach in the ovary to obtain a global picture of how the high-fertility phenotype is achieved. We found several differentially expressed genes in the ovaries of FL1 mice that are associated with different female fertility traits. Our results indicate that ovulation rates in mice can be increased despite decreased FSH levels. Cycle-related alterations of progesterone and LH levels have the potential to improve follicular maturation, and interactions of endocrine and molecular factors lead to enhanced follicular survival, more successful folliculogenesis and therefore higher ovulation rates in female FL1 mice.

Chemerin Impact on Alternative mRNA Transcription in the Porcine Luteal Cells

Chemerin participates in the regulation of processes related to physiological and disorder mechanisms in mammals, including metabolism, obesity, inflammation, and reproduction. In this study, we have investigated chemerin influence on alternative mRNA transcription within the porcine luteal cell transcriptome, such as differential expression of long non-coding RNAs (DELs) and their interactions with differentially expressed genes (DEGs), differences in alternative splicing of transcripts (DASs), and allele-specific expression (ASEs) related to the single nucleotide variants (SNVs) frequency. Luteal cells were collected from gilts during the mid-luteal phase of the oestrous cycle. After in vitro culture of cells un-/treated with chemerin, the total RNA was isolated and sequenced using the high-throughput method. The in silico analyses revealed 24 DELs cis interacting with 6 DEGs and trans-correlated with 300 DEGs, 137 DASs events, and 18 ASEs. The results enabled us to analyse metabolic and signalling pathways in detail, providing new insights into the effects of chemerin on the corpus luteum functions related to inflammatory response, leukocyte infiltration, the occurrence of luteotropic and luteolytic signals (leading to apoptosis and/or necroptosis). Validation of the results using qPCR confirmed the predicted expression changes. Chemerin at physiological concentrations significantly modifies the transcription processes in the porcine luteal cells.

Hypoxia: Role of SIRT1 and the protective effect of resveratrol in ovarian function

Background

Ovarian function is closely related to the degree of vascular network development surrounding the ovary. Maternal aging‐related construction defects in this vascular network can cause ovarian hypoxia, which impedes oocyte nutrient supply, leading to physiological changes in the ovaries and oocytes. The anti‐aging gene Sirtuin 1 (SIRT1) senses and adapts to ambient stress and is associated with hypoxic environments and mitochondrial biogenesis.

Methods

The present study is a literature review focusing on investigations involving the changes in SIRT1 and mitochondrial expression during hypoxia and the cytoprotective effects of the SIRT1 activator, resveratrol.

Main findings

Hypoxia suppresses SIRT1 and mitochondrial expression. Resveratrol can reverse the hypoxia‐induced decrease in mitochondrial and SIRT1 activity. Resveratrol suppresses the production of hypoxia‐inducible factor‐1α and vascular endothelial growth factor proteins.

Conclusion

Resveratrol exhibits protective activity against hypoxic stress and may prevent hypoxia‐ or aging‐related mitochondrial dysfunction. Resveratrol treatment may be a potential option for infertility therapy.

CXCL12 May Drive Inflammatory Potential in the Ovine Corpus Luteum During Implantation

Adequate corpus luteum (CL) function is paramount to successful pregnancy. Structural and functional CL integrity is controlled by diverse cell types that contribute and respond to the local cytokine milieu. The chemokine ligand 12 (CXCL12) and receptor, CXCR4, are modulators of inflammation and cell survival, but little is understood about CXCL12-CXCR4 axis and CL functional regulation. Corpora lutea from control nonpregnant ewes (n = 5; day 10 estrous cycle (D10C)) and pregnant ewes (n = 5/day) on days 20 (D20P) and 30 (D30P) post-breeding were analyzed for gene and protein expression of CXCL12, CXCR4, and select inflammatory cytokines. In separate cell culture studies, cytokine production was evaluated following CXCL12 treatment. Abundance of CXCL12 and CXCR4 increased (P < 0.05) in pregnant ewes compared to nonpregnant ewes, as determined by a combination of quantitative PCR, immunoblot, and immunofluorescence microscopy. CXCR4 was detected in steroidogenic and nonsteroidogenic cells in ovine CL, and select pro-inflammatory mediators were greater in CL from pregnant ewes. In vitro studies revealed greater abundance of tumor necrosis factor (TNF) following CXCL12 administration (P = 0.05), while P4 levels in cell media were unchanged. Fully functional CL of pregnant ewes is characterized by increased abundance of inflammatory cytokines which may function in a luteotropic manner. We report concurrent increases in CXCL12, CXCR4, and select inflammatory mediators in ovine CL as early pregnancy progresses. We propose CXCL12 stimulates production of select cytokines, rather than P4 in the CL to assist in CL establishment and survival.

Intraovarian injection of platelet-rich plasma in assisted reproduction: too much too soon?

The prospect of ovarian rejuvenation offers the tantalising prospect of treating age-related declines in fertility or in pathological conditions such as premature ovarian failure. The concept of ovarian rejuvenation was invigorated by the indication of the existence of oogonial stem cells (OSCs), which have been shown experimentally to have the ability to differentiate into functional follicles and generate oocytes; however, their clinical potential remains unknown. Furthermore, there is now growing interest in performing ovarian rejuvenation in situ. One proposed approach involves injecting the ovary with platelet rich plasma (PRP).

PRP is a component of blood that remains after the in vitro removal of red and white blood cells. It contains blood platelets, tiny anucleate cells of the blood, which are responsible for forming athrombus to prevent bleeding. In addition, PRP contains an array of cytokines and growth factors, as well as a number of small molecules.The utility ofPRP has been investigatedin a range of regenerative medicine approaches and has been shown to induce differentiation of a range of cell types, presumably through the action of cytokines.

A handful ofcasereports have described the use of PRP injections into the ovaryin the human, and while these clinical data report promising results, knowledge on the mechanisms and safety of PRP injections into the ovary remain limited.In this article, we summarise some of the physiological detail of platelets and PRP, before reviewing the existing emerging literature in this area. We then propose potential mechanisms by which PRP may be eliciting any effects before reflecting on some considerations for future studies in the area. Importantly, on the basis of our existing knowledge, we suggest that immediate use of PRP in clinical applications is perhaps premature and further fundamental and clinical research on the nature of ovarian insufficiency, as well as the mechanism by which PRP may act on the ovary, is needed to fully understand this promising development.

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.

Engineered Three-Dimensional Tumor Models to Study Natural Killer Cell Suppression

A critical hurdle associated with natural killer (NK) cell immunotherapies is inadequate infiltration and function in the solid tumor microenvironment. Well-controlled 3D culture systems could advance our understanding of the role of various biophysical and biochemical cues that impact NK cell migration in solid tumors. The objectives of this study were to establish a biomaterial which (i) supports NK cell migration and (ii) recapitulates features of the in vivo solid tumor microenvironment, to study NK infiltration and function in a 3D system. Using peptide-functionalized poly(ethylene glycol)-based hydrogels, the extent of NK-92 cell migration was observed to be largely dependent on the density of integrin binding sites and the presence of matrix metalloproteinase degradable sites. When lung cancer cells were encapsulated into the hydrogels to create tumor microenvironments, the extent of NK-92 cell migration and functional activity was dependent on the cancer cell type and duration of 3D culture. NK-92 cells showed greater migration into the models consisting of nonmetastatic A549 cells relative to metastatic H1299 cells, and reduced migration in both models when cancer cells were cultured for 7 days versus 1 day. In addition, the production of NK cell-related pro-inflammatory cytokines and chemokines was reduced in H1299 models relative to A549 models. These differences in NK-92 cell migration and cytokine/chemokine production corresponded to differences in the production of various immunomodulatory molecules by the different cancer cells, namely, the H1299 models showed increased stress ligand shedding and immunosuppressive cytokine production, particularly TGF-β. Indeed, inhibition of TGF-β receptor I in NK-92 cells restored their infiltration in H1299 models to levels similar to that in A549 models and increased overall infiltration in both models. Relative to conventional 2D cocultures, NK-92 cell mediated cytotoxicity was reduced in the 3D tumor models, suggesting the hydrogel serves to mimic some features of the biophysical barriers in in vivo tumor microenvironments. This study demonstrates the feasibility of a synthetic hydrogel system for investigating the biophysical and biochemical cues impacting NK cell infiltration and NK cell-cancer cell interactions in the solid tumor microenvironment.

Expression and function of the stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) in the swine ovarian follicle

The most characterized stromal cell-derived factor-1 (SDF-1) variants are the isoform α, which is the predominant one but undergoes rapid proteolysis, and the β isoform, which is more resistant. Through the interaction with a specific chemokine receptor called CXCR4, SDF-1 is able to regulate different physiological processes. The aim of this study was to verify the expression and potential functional role of SDF-1 and CXCR4 in the porcine ovary. Firstly, the expression of SDF-1 and its receptor in different ovarian districts was verified for the first time. Thereafter, the effect of SDF-1 β isoform (51-72) fragment on functional parameters, such as proliferation, metabolic activity, redox status, nitric oxide production, and steroidogenic activity, was assessed on granulosa cells collected from follicles. In addition, the potential effect of this protein in vascular events was verified through investigations on porcine aortic (AOC) endothelial cells, such as the production of nitric oxide and viability tests. The proliferation and metabolic activity were not affected by treatment with the cytokine. As regard to steroidogenesis, the peptide stimulated both estrogen (P = 0.049) and progesterone production (P = 0.039). Redox status was affected by the examined substance since superoxide anion was inhibited (P = 0.001), while antioxidant power (P = 0.034), as well as nitric oxide generation, were stimulated (P = 0.034). Tests performed on AOCs showed significant stimulation of nitric oxide production (P = 0.004) by the examined peptide, while cell viability was unaffected. Therefore, the potential role of cytokine in the mechanisms involved in the regulation of follicular function can be hypothesized.

Immunophenotypic Profiles in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) a long-known endocrinopathy and one of the most common endocrine-reproductive-metabolic disorders in women, which can lead to infertility. Although the precise etiology remains unclear, PCOS is considered as a complex genetic trait, with a high degree of heterogeneity. Besides, hormones and immune cells, including both innate and adaptive immune cells, are reportedly a cross talk in PCOS. Chronic low-grade inflammation increases autoimmune disease risk. This proinflammatory condition may, in turn, affect vital physiological processes that ultimately cause infertility, such as ovulation failure and embryo implantation. Here, we review the accumulating evidence linking PCOS with inflammatory status providing an overview of the underlying hormone-mediated dysregulation of immune cells. We mainly focus on the correlational evidence of associations between immune status in women and the increased prevalence of PCOS, along with the specific changes in immune responses. Further recognition and exploration of these interactions may help elucidate PCOS pathophysiology and highlight targets for its treatment and prevention.

Ovarian and endometrial immunity during the ovarian cycle

Immune tolerance is crucial for the successful pregnancy, while immune effectors and their products are required to safeguard a fetus from the infectious pathogens. The key immune effectors, such as T, B, and natural killer (NK) cells, monocytes, macrophages, and dendritic cells take part in regulating the immune responses at the maternal-fetal interface. The immune effectors become involved in intraovarian reproductive processes as well, such as ovulation, production of corpus luteum (CL) and its degeneration and determine the quality and evolution of the oocyte during the folliculogenesis. In the cycling endometrium, NK cells are rapidly infiltrated into the endometrium after ovulation and participate in angiogenesis and spiral artery remodeling process. In this study, we reviewed the characteristics and action mechanisms of immune effectors and their products in the peripheral blood, ovary, and endometrium during the ovarian cycle, since a comprehensive understanding of immune responses during the ovarian cycle and the time of implantation can help us to predict the pregnancy outcome and take effective measures for the prevention of potential obstetrical complications.

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.

Concentration of stromal cell-derived factor-1 (SDF-1/CXCL12) in the follicular fluid is associated with blastocyst development

PURPOSE

To study the association between stromal cell-derived factor-1 (SDF-1/CXCL12) and vascular endothelial growth factor (VEGF) concentrations in individual human ovarian follicles and IVF outcomes.

METHODS

Concentrations of SDF-1 and VEGF in 261 follicular fluid samples were measured with enzyme-linked immunosorbent assay. IVF outcome parameters were included in fertilization rate, cleavage rate, embryo morphology on day 3, and blastocyst morphology on day 5.

RESULTS

The follicular concentration of SDF-1 and VEGF was not significantly associated with fertilization and cleavage outcome, and embryo morphology. The rates of full blastocysts and good-quality blastocysts were significantly higher in follicles with an SDF-1 concentration of 275-350 pg/mL than in the follicles with SDF-1 concentrations of <200 and ≥350 pg/mL (P < 0.05). The follicular concentration of VEGF was not associated with the blastocyst morphology.

CONCLUSION

Our findings showed that follicular concentration of SDF-1, and not VEGF, may be a valuable biochemical marker of blastocyst development.

Supplementation with CTGF, SDF1, NGF, and HGF promotes ovine in vitro oocyte maturation and early embryo development

The strategies for improving the in vitro maturation (IVM) of domestic animal oocytes focus on promoting nuclear and cytoplasmic maturation. The identification of paracrine factors and their supplementation in the culture medium represent effective approaches for oocyte maturation and embryo development. This study investigated the effects of paracrine factor supplementation including connective tissue growth factor (CTGF), nerve growth factor (NGF), hepatocyte growth factor (HGF), and stromal derived factor 1 (SDF1) on ovine oocytes and early parthenogenetic embryos using an in vitro culture system. First, we identified the optimal concentrations of CTGF (30 ng/mL), SDF1 (10 ng/mL), NGF (3 ng/mL), and HGF (100 ng/mL) for promoting oocyte maturation, which combined, induced nuclear maturation in 94.19% of oocytes. This combination also promoted cumulus cell expansion and inhibited oocyte/cumulus apoptosis, while enabling a larger proportion (33.04%) of embryos to develop into blastocysts than in the controls and prevented embryo apoptosis. These novel findings demonstrate that the paracrine factors CTGF, SDF1, NGF, and HGF facilitate ovine oocyte and early parthenogenetic embryo development in vitro. Thus, supplementation with these factors may help optimize the IVM of ovine oocytes and early parthenogenetic embryo development strategies.

Stroma cell-derived factor 1 and connexins (37 and 43) are preserved after vitrification and in vitro culture of goat ovarian cortex

This study aimed to evaluate the follicular morphology and development (follicular activation, cell proliferation, and hormone production), as well as the distribution pattern of Connexins 37 and 43 and SDF-1α after vitrification and in vitro culture of goat ovarian tissue. The study involved four experimental groups: fresh control, vitrified control, fresh culture and vitrified culture. The ovarian fragments were vitrified by a solid surface technique using the Ovarian Tissue Cryosystem and subsequently in vitro cultured for 7 days. The percentage of normal preantral follicles was similar between vitrified control and vitrified culture. However, both vitrified control and vitrified culture treatments showed a significant reduction of morphologically normal follicles in comparison to fresh control. A higher percentage of developing follicles (transition, primary and secondary) was observed in both fresh culture and vitrified culture treatments. Progesterone and estradiol production decreased (P < 0.05) during in vitro culture. SDF-1α and Cx37 proteins were detected in oocytes and granulosa cells from all the treatments. However, in vitrified cultured tissue, only granulosa cells were labeled with Cx37. Connexin 43 was detected in the granulosa, theca cells and zona pellucida in all the treatments. In conclusion, in vitro culture of vitrified goat ovarian cortex was able to promote follicle survival and did not alter the expression of SDF-1α and 43. However, the expression of Cx 37 was modified after in vitro culture of vitrified tissue.

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.

Supplementation of freezing media with stromal cell-derived factor-1α preserves human sperm from cryodamage

The destructive effects of sperm cryopreservation result in reduced sperm motility and increased apoptosis. Oocytes, endometrium, and follicular fluid express stromal cell-derived factor-1 alpha (SDF-1α) or C-X-C motif chemokine ligand 12 (CXCL12) while its specific receptor chemokine, CXC motif receptor 4 (CXCR4) is expressed in the head of sperm. SDF-1α can increase sperm motility and preserve normal mitochondrial status. The present study intends to investigate whether the addition of SDF-1α to freezing extender can facilitate cryosurvival of spermatozoa and how SDF-1α protects spermatozoa against damages during cryopreservation. In this study, we collected 22 semen samples from healthy donors and treated them with different concentrations of SDF-1α, followed by cryopreservation for one month. We measured sperm motility by CASA, mitochondrial ROS generation by flow cytometry using the probe MitoSOX Red™ (MSR) to measure mitochondrial superoxide anion (O2^-•), DNA fragmentation by flow cytometry according to the TUNEL kit, and expressions of Bcl-2 and Bax by RT-qPCR in freeze-thawed sperm. The results showed that SDF-1α attenuated mitochondrial ROS generation at different doses, particularly the 250 ng/ml treated samples which, in turn, reduced the expressions of pro-apoptotic genes such as Bax. Eventually, SDF-1α reduced DNA fragmentation and ameliorated sperm motility in the 1-100 ng/ml treated samples during cryopreservation. The present study, for the first time, demonstrated that SDF-1α dose-dependently moderated oxidative stress injury in human sperm by reduction of mitochondrial ROS generation. It could subsequently cause a decrease in apoptosis during freeze-thawing and protect human spermatozoa from cryodamage.

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.

X-linked lymphocyte regulated gene 5c-like (Xlr5c-like) is a novel target of progesterone action in granulosa cells of periovulatory rat ovaries

Progesterone (P4), acting through its nuclear receptor (PGR), plays an essential role in ovulation by mediating the expression of genes involved in ovulation and/or luteal formation. To identify ovulatory specific PGR-regulated genes, a preliminary microarray analysis was performed using rat granulosa cells treated with hCG ± RU486 (PGR antagonist). The transcript most highly down-regulated by RU486 was an EST (expressed sequence tag) sequence (gb: BI289578.1) that matches with predicted sequence for Xlr5c-like mRNA. Since nothing is known about Xlr5c-like, we first characterized the expression pattern of Xlr5c-like mRNA in the rat ovary. The level of mRNA for Xlr5c-like is transiently up-regulated in granulosa cells of periovulatory follicles after hCG stimulation in PMSG-primed rat ovaries. The transient induction of Xlr5c-like mRNA was mimicked by hCG treatment in cultured granulosa cells from preovulatory ovaries. We further demonstrated that the LH-activated PKA, MEK, PI3K, and p38 signaling is involved in the increase in Xlr5c-like mRNA. The increase in Xlr5c-like mRNA was abolished by RU486. The inhibitory effect of RU486 was reversed by MPA (synthetic progestin), but not by dexamethasone (synthetic glucocorticoid). Furthermore, mutation of SP1/SP3 and PGR response element sites in the promoter region of Xlr5c-like decreased Xlr5c-like reporter activity. RU486 also inhibited Xlr5c-like reporter activity. ChIP assay verified the binding of PGR and SP3 to the Xlr5c-like promoter in periovulatory granulosa cells. Functionally, siRNA-mediated Xlr5c-like knockdown in granulosa cell cultures resulted in reduced levels of mRNA for Snap25, Cxcr4, and Adamts1. Recombinant Xlr5c-like protein expressed using an adenoviral approach was localized predominantly to the nucleus and to a lesser extent to the cytoplasm of rat granulosa cells. In conclusion, this is the first report showing the spatiotemporally regulated expression of Xlr5c-like mRNA by hCG in rat periovulatory ovaries. P4/PGR mediates the LH-induced increase in Xlr5c-like mRNA. In turn, Xlr5c-like is involved in regulating the expression of specific ovulatory genes such as Snap25, Cxcr4, and Adamts1, possibly acting in the nucleus of periovulatory granulosa cells.

Epithelial and stromal-specific immune pathway activation in the murine endometrium post-coitum

The endometrium is a dynamic tissue, demonstrating cyclical growth/remodelling in preparation for implantation. In mice, seminal constituents trigger mechanisms to prepare the endometrium, a process dubbed 'seminal priming' that modifies immune system components and mediates endometrial remodelling in preparation for pregnancy. An array of cytokines has been reported to mediate this interaction, although much of the literature relates to in vitro studies on isolated endometrial epithelial cells. This study measured changes in immune-related gene expression in endometrial epithelial and stromal cells in vivo following natural mating. CD1 mice were naturally mated and sacrificed over the first 4 days post-coitum (n=3 each day). Endometrial epithelial and stromal compartments were isolated by laser capture microdissection. Labelled cRNA was generated and hybridised to genome-wide expression microarrays. Pathway analysis identified several immune-related pathways active within epithelial and stromal compartments, in particular relating to cytokine networks, matrix metalloproteinases and prostaglandin synthesis. Cluster analysis demonstrated that the expression of factors involved in immunomodulation/endometrial remodelling differed between the epithelial and stromal compartments in a temporal fashion. This study is the first to examine the disparate responses of the endometrial epithelial and stromal compartments to seminal plasma in vivo in mice, and demonstrates the complexity of the interactions between these two compartments needed to create a permissive environment for implantation.

Human chorionic gonadotropin increases serum progesterone, number of corpora lutea and angiogenic factors in pregnant sheep

Early gestation is a critical period when implantation and placental vascularization are established, processes influenced by progesterone (P4). Although human chorionic gonadotropin (hCG) is not endogenously synthesized by livestock, it binds the LH receptor, stimulating P4 synthesis. We hypothesized treating pregnant ewes with hCG would increase serum P4, number of corpora lutea (CLs) and concepti, augment steroidogenic enzymes, and increase membrane P4 receptors (PAQRs) and angiogenic factors in reproductive tissues. The objective was to determine molecular alterations induced by hCG in pregnant sheep that may promote pregnancy. Ewes received either 600 IU of hCG or saline i.m. on day 4 post mating. Blood samples were collected daily from day 0 until tissue collection for serum P4 analysis. Reproductive tissues were collected on either day 13 or 25 of gestation and analyzed for PAQRs, CXCR4, proangiogenic factors and steroidogenic enzymes. Ewes receiving hCG had more CL and greater serum P4, which remained elevated. On day 25, StAR protein production decreased in CL from hCG-treated ewes while HSD3B1 was unchanged; further, expression of CXCR4 significantly increased and KDR tended to increase. PAQR7 and CXCR4 protein was increased in caruncle tissue from hCG-treated ewes. Maternal hCG exposure influenced fetal extraembryonic tissues, as VEGFA, VEGFB, FLT1, and ANGPT1 expression increased. Our results indicate hCG increases serum P4 due to augmented CL number per ewe. hCG treatment resulted in greater PAQR7 and CXCR4 in maternal endometrium and promoted expression of proangiogenic factors in fetal extraembryonic membranes. Supplementing livestock with hCG may boost P4 levels and improve reproductive efficiency.

Impact of CD4+ lymphocytes and HIV infection on Anti-Müllerian Hormone levels in a large cohort of HIV-infected and HIV-uninfected women

PROBLEM

Effects of HIV infection on ovarian function and aging are unclear.

METHOD OF STUDY

Anti-Müllerian Hormone (AMH) levels were analyzed in 2621 HIV-infected and 941 uninfected participants using left-censored longitudinal models.

RESULTS

Age-adjusted AMH levels were 16% lower in women with undetectable viraemia and 26% lower in detectable viraemia, relative to uninfected women. Current CD4 count associated with higher AMH in both HIV-infected and HIV-uninfected women. After controlling for current and nadir CD4, AMH was ~15% higher in HIV-infected relative to uninfected women, regardless of HIV viraemia. Gravidity, amenorrhea, and nadir total lymphocyte counts associated with higher AMH; hormonal contraceptive use and past weight loss associated with lower AMH.

CONCLUSIONS

CD4 +  lymphocyte counts were associated with AMH in both HIV-infected and uninfected women. After adjustment for CD4 counts and age, HIV infection was associated with higher AMH. CD4 T cells and cellular activation may influence ovarian granulosa cell function.

Expression and regulation of stromal cell-derived factor-1 (SDF1) and chemokine CXC motif receptor 4 (CXCR4) in equine and bovine preovulatory follicles

The interaction between stromal cell-derived factor-1 (SDF1) and chemokine CXC motif receptor 4 (CXCR4) has been implicated in leukocyte attraction, tissue remodeling and angiogenesis. The objective of the present study was to characterize the expression and regulation of SDF1 and CXCR4 in equine follicles during the ovulatory process. Equine preovulatory follicles were isolated during estrus 0-39h after hCG treatment. Follicle wall preparations (theca interna with attached granulosa cells) and isolated preparations of granulosa cells and theca interna were obtained, and total RNA extracts were analyzed by RT-PCR/Southern blot. Results showed that levels of CXCR4 transcripts were induced by hCG in follicles at 36 h post-hCG (P<0.05 vs 0 h), with the induction observed in both granulosa and theca cells. Immunoblotting and immunohistochemical analyses confirmed an increase in CXCR4 protein in follicles after hCG treatment. In contrast, levels of SDF1 transcripts were very low in granulosa cells but high in theca interna cells throughout most of the ovulatory period. Studies in vivo performed with bovine preovulatory follicles collected 0-24h post-hCG revealed a marked and significant up-regulation of CXCR4 transcripts after hCG (P<0.05), as observed in equine follicles. A similar pattern of CXCR4 mRNA up-regulation was observed in cultures of bovine granulosa cells treated with forskolin (P<0.05). This forskolin-dependent induction of CXCR4 mRNA was suppressed by co-treatment with inhibitors of PKA, ERK1/2 and EGFR, and by the progesterone receptor antagonist RU486 (P<0.05), underscoring the contribution of multiple signaling pathways. In complementary studies, treatment of bovine granulosa cells with EGF or the hypoxia mimetic cobalt chloride significantly increased CXCR4 transcript levels, whereas co-treatment with forskolin and a CXCR4 antagonist repressed the expression of several ovulation-related genes. Collectively, this study describes for the first time the gonadotropin-dependent up-regulation of CXCR4 transcript in ovarian follicles of large monoovulatory species, provides some insights into the regulation of CXCR4 gene expression in granulosa cells, and identifies a potential link between follicular SDF1/CXCR4 activation and the regulation of ovulation-related genes.

CXCL12 inhibits cortical neuron apoptosis by increasing the ratio of Bcl-2/Bax after traumatic brain injury

CXCL12 and its physiologic receptor CXCR4 are involved in controlling cell survival, proliferation and migration in adult tissues. This study aimed to investigate the effects of CXCL12 on cortical neuron apoptosis in rats after traumatic brain injury (TBI) and the potential mechanisms involved. At 3 days after TBI, in situ terminal transferase d-UTP nick-end labeling assay (TUNEL) showed that the apoptotic index (AI) deceased significantly in the CXCL12 treatment group compared with the control group (p < 0.05). Immunofluorescence double-labeled staining revealed that most of the TUNEL positive cells were NeuN positive neurons. The change trends of active caspase-3 expression were similar as those of the AI. The Bcl-2:Bax ratio was upregulated in the CXCL12 group compared with the control group. However, the effect of CXCL12 could be partially reverted by the additional use of AMD3100 (a kind of antagonist of CXCR4) (p < 0.05). Our results indicated that after TBI in rats CXCL12 combing CXCR4 receptors could inhibit the caspase-3 pathway by upregulating Bcl-2:Bax ratio, which protect neurons from apoptosis.

Effects of CXCR4 gene silencing by lentivirus shRNA on proliferation of the EC9706 human esophageal carcinoma cell line

CXCL12/CXCR4 has been studied as an important biomarker for many human malignancies, but studies are limited for esophageal squamous cell carcinoma (ESCC). In this study, an effective RNAi sequence targeting the CXCR4 gene was selected, a lentiviral shRNA vector was constructed to specifically silence CXCR4 expression in the EC9706 ESCC cell line, and the effects of CXCR4 silencing on cell growth in vitro and tumour growth in nude mice were then evaluated. The expression of CXCR4 in EC9706 was significantly downregulated after transfection with a lentiviral shRNA vector. The expression of the apoptosis-related gene Bcl-2 was decreased. In addition, after CXCR4 inhibition, cell growth was considerably inhibited, increased apoptosis in the EC9706 cells was found, the G0/G1 percentage was significantly increased, and the number of cells in S phase was reduced. Moreover, tumour growth in nude mice was inhibited. In conclusion, the downregulation of CXCR4 expression by transfection with a lentiviral shRNA vector in ESCC cells could inhibit tumour proliferation. Our data may provide an avenue for finding new ESCC treatments.

The concentration of human follicular fluid stromal cell-derived factor-1 is correlated with luteinization in follicles

Stromal cell-derived factor-1 (SDF-1/CXCL12) and vascular endothelial growth factor (VEGF) are angiogenic factors that have possible roles in ovarian function. The objectives of this study were to investigate the association between the individual concentrations of SDF-1 and VEGF and sex steroid hormones in human preovulatory follicles and to verify the SDF-1 expression in ovarian follicles. Follicular fluid (FF) and luteinizing granulosa cells (LGCs) were collected from follicles at the time of oocyte retrieval. The concentrations of SDF-1, VEGF, estradiol (E₂) and progesterone (P₄) were determined by biochemical assay. The expression levels of SDF-1 mRNA and protein were analyzed by RT-PCR and immunohistochemical analysis, respectively. A total of 177 follicles were analyzed. The FF concentrations of SDF-1 and VEGF positively correlated with P₄ concentrations (r = 0.457 and p < 0.01, r = 0.698 and p < 0.01, respectively), but did not correlate with E₂ concentrations in FF. Furthermore, we confirmed that SDF-1 mRNA was expressed in LGCs and SDF-1 protein is present in the granulosa cells of the human ovary. Our findings suggest that SDF-1, as well as VEGF, may play important modulatory roles in early luteinization of human preovulatory follicles.

An important role of blood and lymphatic vessels in inflammation and allergy

Angiogenesis and lymphangiogenesis, the growth of new vessels from preexisting ones, have received increasing interest due to their role in tumor growth and metastatic spread. However, vascular remodeling, associated with vascular hyperpermeability, is also a key feature of many chronic inflammatory diseases including asthma, atopic dermatitis, psoriasis, and rheumatoid arthritis. The major drivers of angiogenesis and lymphangiogenesis are vascular endothelial growth factor- (VEGF-)A and VEGF-C, activating specific VEGF receptors on the lymphatic and blood vascular endothelium. Recent experimental studies found potent anti-inflammatory responses after targeted inhibition of activated blood vessels in models of chronic inflammatory diseases. Importantly, our recent results indicate that specific activation of lymphatic vessels reduces both acute and chronic skin inflammation. Thus, antiangiogenic and prolymphangiogenic therapies might represent a new approach to treat chronic inflammatory disorders, including those due to chronic allergic inflammation.

Gene expression differences induced by equimolar low doses of LH or hCG in combination with FSH in cultured mouse antral follicles

In a natural cycle, follicle growth is coordinated by FSH and LH. Follicle growth stimulation in Assisted Reproductive Technologies (ART) requires antral follicles to be exposed to both FSH and LH bioactivity, especially after GNRH analog pretreatment. The main aim was to detect possible differences in gene expression in granulosa cells after exposing the follicle during antral growth to LH or hCG, as LH and hCG are different molecules acting on the same receptor. Effects of five gonadotropin treatments were investigated for 16 genes using a mouse follicle culture model. Early (day 6) antral follicles were exposed to high recombinant FSH combined or not with equimolar concentrations of recombinant LH (rLH) or recombinant hCG (rhCG) and to highly purified human menopausal gonadotropin (HP-hMG) for 6 h, 12 h, or 3 days. Expression differences were tested for genes involved in steroidogenesis: Mvk, Lss, Cyp11a1, Hsd3b1, Cyp19a1, Nr4a1, and Timp1; final granulosa differentiation: Lhcgr, Oxtr, Pgr, Egfr, Hif1a, and Vegfa; and cytokines: Cxcl12, Cxcr4, and Sdc4. Lhcgr was present and upregulated by gonadotropins. Nr4a1, Cxcl12, and Cxcr4 showed a different expression pattern if LH bioactivity was added to high FSH in the first hours after exposure. However, no signs of premature luteinization were present even after a 3-day treatment as shown by Cyp19a1, Oxtr, Pgr, and Egfr and by estrogen and progesterone measurements. The downstream signaling by rhCG or rLH through the LHCGR was not different for this gene selection. Granulosa cells from follicles exposed to HP-hMG showed an enhanced expression level for several genes compared with recombinant gonadotropin exposure, possibly pointing to enhanced cellular activity.

Expression of SDF-1α and leptin, and their effect on expression of angiogenic factors in mouse ovaries

OBJECTIVE

Ovarian angiogenesis plays an important role in folliculogenesis. However, little is known about the expression of angiogenic factors during follicular development according to female age. Stromal cell derived factor-1α (SDF-1α) plays a role in granulosa cell survival and embryo quality as an angiogenic chemokine. Leptin is also involved in folliculogenesis and angiogenesis. This study examined expression of SDF-1α and leptin, and their effects on the expression of angiogenic factors in the ovary during follicular development according to female age.

METHODS

Ovaries were collected from C57BL mice of two age groups (6-9 weeks and 24-26 weeks) at 6, 12, 24, and 48 hours after 5 IU pregnant mare's serum gonadotropin (PMSG) injection. The expression of ovarian SDF-1α and leptin mRNA was evaluated by RT-PCR. In the organ culture experiment, the ovaries were cultured in transwell permeable supports with Waymouth's medium treated with various doses of SDF-1α (50-200 ng/mL) or leptin (0.01-1 µg/mL) for 7 days. Then, mRNA expression of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), and visfatin were examined in the cultured ovaries.

RESULTS

Expression of SDF-1α and leptin in the ovary was significantly lower in the aged mouse group compared to the young mouse group (p<0.05). Expression of these two factors increased with follicular development after PMSG administration. SDF-1α treatment stimulated visfatin expression in a dose-dependent manner, while leptin treatment significantly increased eNOS expression.

CONCLUSION

These results suggest that decrease of ovarian SDF-1α and leptin expression may be associated with aging-related reduction of ovarian function. SDF-1α and leptin may play a role in follicular development by regulating the expression of angiogenic factors in mouse ovaries.

CXCL12 expression by healthy and malignant ovarian epithelial cells

Background

CXCL12 has been widely reported to play a biologically relevant role in tumor growth and spread. In epithelial ovarian cancer (EOC), CXCL12 enhances tumor angiogenesis and contributes to the immunosuppressive network. However, its prognostic significance remains unclear. We thus compared CXCL12 status in healthy and malignant ovaries, to assess its prognostic value.

Methods

Immunohistochemistry was used to analyze CXCL12 expression in the reproductive tracts, including the ovaries and fallopian tubes, of healthy women, in benign and borderline epithelial tumors, and in a series of 183 tumor specimens from patients with advanced primary EOC enrolled in a multicenter prospective clinical trial of paclitaxel/carboplatin/gemcitabine-based chemotherapy (GINECO study). Univariate COX model analysis was performed to assess the prognostic value of clinical and biological variables. Kaplan-Meier methods were used to generate progression-free and overall survival curves.

Results

Epithelial cells from the surface of the ovary and the fallopian tubes stained positive for CXCL12, whereas the follicles within the ovary did not. Epithelial cells in benign, borderline and malignant tumors also expressed CXCL12. In EOC specimens, CXCL12 immunoreactivity was observed mostly in epithelial tumor cells. The intensity of the signal obtained ranged from strong in 86 cases (47%) to absent in 18 cases (<10%). This uneven distribution of CXCL12 did not reflect the morphological heterogeneity of EOC. CXCL12 expression levels were not correlated with any of the clinical parameters currently used to determine EOC prognosis or with HER2 status. They also had no impact on progression-free or overall survival.

Conclusion

Our findings highlight the previously unappreciated constitutive expression of CXCL12 on healthy epithelia of the ovary surface and fallopian tubes, indicating that EOC may originate from either of these epithelia. We reveal that CXCL12 production by malignant epithelial cells precedes tumorigenesis and we confirm in a large cohort of patients with advanced EOC that CXCL12 expression level in EOC is not a valuable prognostic factor in itself.

Trial Registration

ClinicalTrials.gov: NCT00052468

Pathophysiological roles of chemokines in human reproduction: an overview

Chemokines are a group of small cytokines that have an ability to induce leukocyte migration. Chemokines exert their functions by binding and activating specific G protein-coupled receptors. Studies have unveiled pleiotropic bioactivities of chemokines in various phenomena ranging from immunomodulation, embryogenesis, and homeostasis to pathogenesis. In the mammalian reproductive system, chemokines unexceptionally serve in multimodal events that are closely associated with establishment, maintenance, and deterioration of fecundity. The aim of this review is to update the knowledge on chemokines in male and female genital organs, with a focus on their potential pathophysiological roles in human reproduction.

The interface of the immune and reproductive systems in the ovary: lessons learned from the corpus luteum of domestic animal models

The dynamic changes that characterize the female reproductive system are regulated by hormones. However, local cell-to-cell interactions may mediate responsiveness of tissues to hormonal signals. The corpus luteum (CL) is an excellent model for understanding how immune cells are recruited into tissues and the role played by those cells in regulating tissue homeostasis or demise. Leukocytes are recruited into the CL throughout its lifespan, and leukocyte-derived cytokines have been found in corpora lutea of all species examined. The proinflammatory cytokines inhibit gonadotropin-stimulated steroidogenesis, profoundly stimulate prostaglandin synthesis by luteal cells, and promote apoptosis. However, there is mounting evidence that leukocytes and luteal cells communicate in different ways to maintain homeostasis within the functional CL. Domestic animals have provided important information regarding the presence and role of immune cells in the CL.

Influence of ovarian stage on transcript profiles in fathead minnow (Pimephales promelas) ovary tissue

Interpretation of toxicogenomic experiments conducted with ovary tissue from asynchronous-spawning small fish species is complicated by background variation in the relative abundance and proportion of follicles at different stages within the ovary tissue sample. This study employed both real-time quantitative polymerase chain reaction and a 15,000 gene oligonucleotide microarray to examine variation in the fathead minnow (Pimephales promelas) ovarian transcriptional profile as a function of quantitative and qualitative differences in ovarian histology. The objectives were to provide data that could potentially aid interpretation of future toxicogenomics experiments, identify putative stage-related transcriptional markers, and generate insights into basic biological regulation of asynchronous oocyte development. Multiple lines of evidence from the present study indicate that variation in the transcriptional profile is primarily dependent on the relative abundance of previtellogenic versus vitellogenic follicles in the ovary. Due to the relatively small proportions of mature ovulated follicles or atretic follicles in the overall follicle population, few potential transcriptional markers of maturation, ovulation, or atresia could be identified. However, among the 460 differentially expressed genes identified in the present study, several targets, including HtrA serine peptidase 3 (htra3), tissue inhibitor of metalloproteinase 3 (timp3), aquaporin 8 (aqp8), transgelin 2 like (tagln2), Nedd4 family interacting protein 2 (ndfip2), chemokine ligand 12a (cxcl12a), midkine-related growth factor (mdka), and jagged 1b (jag 1b) exhibited responses and functional properties that support them as candidate molecular markers of significant shift in gross ovarian stage. Genes associated with a diversity of functions including cellular development, morphogenesis, coated vesicle transport, sexual reproduction, and neuron development, among others, were statistically enriched within the list of 460 genes differentially expressed among different ovarian classes. Overall, results of this study provide insights into background variation in ovary transcript profiles that should aid and enhance the interpretation of toxicogenomic data generated in experiments conducted with small, asynchronous-spawning fish species.

SDF-1alpha/CXCL12 enhances GABA and glutamate synaptic activity at serotonin neurons in the rat dorsal raphe nucleus

The serotonin (5-hydroxytryptamine; 5-HT) system has a well-characterized role in depression. Recent reports describe comorbidities of mood-immune disorders, suggesting an immunological component may contribute to the pathogenesis of depression as well. Chemokines, immune proteins which mediate leukocyte trafficking, and their receptors are widely distributed in the brain, mediate neuronal patterning, and modulate various neuropathologies. The purpose of this study was to investigate the neuroanatomical relationship and functional impact of the chemokine stromal cell-derived factor-1alpha/CXCL12 and its receptor, CXCR4, on the serotonin dorsal raphe nucleus (DRN) system in the rat using anatomical and electrophysiological techniques. Immunohistochemical analysis indicates that over 70% of 5-HT neurons colocalize with CXCL12 and CXCR4. At a subcellular level, CXCL12 localizes throughout the cytoplasm whereas CXCR4 concentrates to the outer membrane and processes of 5-HT neurons. CXCL12 and CXCR4 also colocalize on individual DRN cells. Furthermore, electrophysiological studies demonstrate CXCL12 depolarization of 5-HT neurons indirectly via glutamate synaptic inputs. CXCL12 also enhances the frequency of spontaneous inhibitory and excitatory postsynaptic currents (sIPSC and sEPSC). CXCL12 concentration-dependently increases evoked IPSC amplitude and decreases evoked IPSC paired-pulse ratio selectively in 5-HT neurons, effects blocked by the CXCR4 antagonist AMD3100. These data indicate presynaptic enhancement of GABA and glutamate release at 5-HT DRN neurons by CXCL12. Immunohistochemical analysis further shows CXCR4 localization to DRN GABA neurons, providing an anatomical basis for CXCL12 effects on GABA release. Thus, CXCL12 indirectly modulates 5-HT neurotransmission via GABA and glutamate synaptic afferents. Future therapies targeting CXCL12 and other chemokines may treat serotonin related mood disorders, particularly depression experienced by immune-compromised individuals.

A differential cytokine expression profile is induced by highly purified human menopausal gonadotropin and recombinant follicle-stimulating hormone in a pre- and postovulatory mouse follicle culture model

OBJECTIVE

To compare the differential effects of highly purified (HP) hMG or recombinant FSH (rFSH) on cytokine expression before and after ovulation in an in vitro mouse ovarian follicle model.

DESIGN

A prospective laboratory in vitro study.

SETTING

A university-based reproductive biology laboratory. MATERIAL(S): Mechanically isolated mouse preantral follicles from 14-day-old prepubertal mouse ovaries (F1 hybrids: C57BL/6JxCBA/ca).

INTERVENTION(S)

Randomly distributed mouse early preantral follicles were exposed to two hyperstimulation conditions with either HP-hMG or rFSH. An ovulatory stimulus was given using hCG/epidermal growth factor. Conditioned media from the two culture conditions were collected on the days before and after in vitro ovulation. Conditioned media were compared for their relative cytokine profile content as measured by a cytokine antibody array analysis.

MAIN OUTCOME MEASURE(S)

Relative concentrations of 62 cytokines in conditioned media before and after ovulation.

RESULT(S)

Statistically significant increase in the production of a number of cytokines was found after HP-hMG stimulation compared with rFSH: 14 and 24 pre- and post-rhCG, respectively. Cytokines with the largest significant difference (more than 5 times) before and after ovulation included thymus-expressed cytokine (TECK), sTNFRI, and SDF-1alpha. The cytokines that are most strongly related to oocyte and embryo quality and implantation and that have been related to oocyte yield and maturation were significantly higher with HP-hMG.

CONCLUSION(S)

The significant differences in follicular cytokine production induced by HP-HMG and rFSH before and after in vitro ovulation might explain the difference in treatment outcome.

Oligosaccharides as anti-angiogenic agents

BACKGROUND

Several studies of drugs that inhibit tumour angiogenesis have shown improvements in the survival of cancer patients, thus validating angiogenesis as a clinically relevant target. Both intracellular and extracellular approaches have shown promising results in clinical situations.

OBJECTIVES

To compare and contrast oligosaccharide therapies and other anti-angiogenic compounds for their benefits and toxicity.

METHODS

Analysis of the relevant literature including presentations at recent conferences.

RESULTS

Receptor tyrosine kinase inhibitors are orally available but have a broad spectrum of activity which is associated with toxicity. Antibodies are associated with different toxicities, however, they are administered parenterally. Oligosaccharides that act as competitive inhibitors of heparan sulfate (HS) are in the early and late phases of clinical development. The advantage of oligosaccharides should be that they can be designed to target several angiogenic molecules, that they are relatively safe and that they can be administered subcutaneously at home. The key questions concerning their development focus on whether compounds with sufficient affinity and relative specificity can be generated, whether they are active at doses that do not perturb the coagulation cascade to a clinically dangerous level, whether the synthetic routes are scalable and, whether the current Phase III trials will yield positive results.

CONCLUSIONS

Saccharides represent a novel and exciting therapeutic approach that targets a spectrum of angiogenic molecules that cannot be inhibited through established drug development programmes.