146. MACROPHAGES ARE ESSENTIAL FOR MAINTENANCE OF EARLY PREGNANCY THROUGH REGULATION OF CORPUS LUTEUM FUNCTION

Macrophages are abundant within the ovary, and have been identified in the corpus luteum (CL) of most species studied, including in rodents and human. Through their secretory products, macrophages are thought to be involved in ovarian tissue remodelling, including luteinization, and in regulating steroidogenesis [1, 2]. Macrophages co-cultured with granulosa or luteal cells act to stimulate progesterone secretion [3]. To determine the impact of macrophage ablation during early pregnancy, we utilised the macrophage specific CD11b-DTR diphtheria toxin receptor (DTR) transgenic mouse to cause transient systemic ablation of macrophages via the administration of DT (25 ng/g). The effects of macrophage ablation during the pre-implantation phase of pregnancy were evaluated and implantation sites were counted. Ablation of macrophages on day 1 pc (n=13 wild-type; n=9 CD11b-DTR) or day 4 pc (n=6 CD11b-DTR; n=9 wild-type) caused complete pregnancy loss in all DT-treated CD11b-DTR mice, while wild-type mice maintained viable pregnancies [mean ± SEM implantation sites = 5.0 ± 1.4 (day 1 treated), and 6.0 ± 1.9 (day 4 treated)]. Serum progesterone was analysed 24 h following macrophage ablation. A single DT injection on day 3 pc significantly reduced serum progesterone (P4) levels [n=7 wild-type P4 (ng/ml)= 29.6 ± 3.3; n=8 CD11b-DTR = 11.1 ± 2.1]. The administration of exogenous P4 (2 mg) on each of day 4-7 pc prevented fetal loss in DT-treated CD11b-DTR mice (n=6; implantation sites = 7.8 ± 1.6), while no pregnancies remained viable in DT-treated mice administered vehicle only (n=9). In conclusion, luteal insufficiency appears to be the cause of pregnancy failure following macrophage ablation. These data indicate a critical role for macrophages in corpus luteum function in early pregnancy.

111. LIF REGULATION OF EPITHELIAL CELL FUCOSYLTRANSFERASE EXPRESSION IN MOUSE ENDOMETRIUM DURING EARLY PREGNANCY

Fucosyltransferase (FUT) enzymes are key regulators of glycosylated structures mediating embryo attachment to uterine epithelial cells at implantation. The identity of local regulatory signals is unknown. We have previously shown that macrophage co-culture significantly increases epithelial cell FUT2 and FUT4 mRNA expression in vitro, and the effect of co-culture is replicated with macrophage conditioned media. We aimed to define the identity of macrophage-secreted agents active in regulating FUT expression in mouse uterine epithelial cells, and to investigate the importance of macrophages for FUT expression in vivo. FUT1, FUT2, and FUT4 mRNAs were measured by qRT-PCR and data was normalised to β-actin mRNA in mouse uterine epithelial cells after culture with cytokines known to be secreted by macrophages. mRNA was also quantified in luminal epithelium laser-microdissected from mouse uterus on day 4 after mating with intact males or seminal vesicle deficient (SVX) males, to induce normal or depleted uterine macrophage populations respectively. Lectin staining on day 4 pc was quantified using ImageJ software in an alternate model of transient, systemic macrophage ablation following diphtheria toxin administration to CD11b-DTR transgenic mice. Epithelial FUT2 mRNA expression was specifically enhanced in vitro by addition of rLIF (2 ng/ml) (mean relative expression ± SEM, control 100 ± 5.6; rLIF 162.1 ± 11.5). Depletion of macrophages by mating with seminal vesicle deficient males reduced epithelial FUT2 mRNA expression on day 4 pc (intact 100 ± 9.1; SVX 73.5 ± 8.6). Depletion of macrophages in the CD11b-DTR mouse model caused a 30% reduction in the expression of the resulting glycoprotein epitope (α1,2 fucose) as observed by intensity of endometrial epithelial UEA-1 staining (control 100 ± 10; CD11b-DTR 72 ± 9) 24 hr post diphtheria toxin administration. In conclusion, these data demonstrate that endometrial epithelial FUT2 mRNA synthesis in preparation for embryo implantation is mediated via LIF and potentially other factors secreted from macrophages recruited during the inflammatory response to insemination. Uterine macrophage abundance and phenotype may thus be a determinant of receptivity to implantation.

412. The role of macrophages in regulating uterine epithelial cell proliferation

During the oestrous cycle, uterine epithelial cells respond to ovarian steroid hormones by producing an array of cytokines and chemokines that cause macrophage recruitment into the uterus and regulate macrophage activation phenotype. In turn, growth factors and cytokines synthesised by macrophages potentially impact epithelial cell proliferation, secretory function and receptivity to embryo attachment. To investigate the hypothesis that uterine macrophages are essential contributors to the proliferation of uterine epithelial cells, we have used an ovariectomy and steroid replacement model in CD11b-DTR ‘Mac-terminator' mice. These mice are engineered for CD11b promoter-driven expression of the monkey diphtheria toxin (DT) receptor, allowing acute systemic ablation of macrophages by administration of human diphtheria toxin (DT). CD11b-DTR mice were ovariectomised, then 2–4 weeks later were primed with E 2, followed by administration of DT (25 ng/g, ip) to effect macrophage depletion, and BrDU to label proliferating cells. Control mice were given PBS instead of DT. Uterine tissues were stained with F4/80 to detect macrophages, and anti-BrDU to detect BrDU+ epithelial cell nuclei. DT treatment was associated with a depletion of >90% of F4/80+ uterine macrophages. However, the numbers of BrDU+ epithelial cells and the architecture of the luminal epithelial surface and abundance of epithelial glands were similar in control and DT-treated uterine tissues. These data suggest that resident macrophages may not be essential for oestrogen-driven uterine epithelial cell proliferation. In ongoing experiments we are assessing the effect of macrophage depletion on epithelial cell expression of functional markers including those involved in regulation of embryo attachment.

Seminal plasma regulates ovarian progesterone production, leukocyte recruitment and follicular cell responses in the pig

Seminal plasma (SP) acts to influence the uterine endometrium after mating, activating synthesis of embryotrophic cytokines and inflammatory changes that condition the tract for embryo implantation and establishing pregnancy. The objective of this study was to investigate in pigs whether the ovary might also be responsive to SP exposure. Prepubertal gilts were synchronised with exogenous gonadotrophins and received transcervical treatment with pooled boar SP or PBS; then the ovarian tissue was recovered at 34 h (preovulation) and on days 5 and 9 after treatment. The ovarian response was assessed by measuring ovulation rate, number and size of corpora lutea, ovarian leukocyte populations, progesterone production in vivo, as well as responses of retrieved granulosa cells cultured in vitro. In SP-treated gilts, leukocyte recruitment into the ovarian tissues was increased fourfold at 34 h, with macrophages comprising the most abundant cell lineage. There was no effect of SP on the number of oocytes ovulated; however, the weight of corpora lutea was increased in SP-treated gilts. SP also induced an increase in plasma progesterone content seen from day 5 to at least day 9 after treatment. In addition, granulosa cells and thecal tissue retrieved from preovulatory follicles of SP-treated gilts were more responsive in vitro to growth factor- and gonadotrophin-stimulated cell proliferation and progesterone synthesis. These results suggest that uterine exposure to SP influences immune cell trafficking in the ovary and enhances steroidogenesis in early pregnancy. The effects of SP on ovarian function potentially contribute to reproductive success in the pig.

Ovarian leukocyte distribution and cytokine/chemokine mRNA expression in follicular fluid cells in women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) affects 5-10% of reproductive-aged women and is commonly associated with anovulatory infertility. Leukocytes, together with granulosa cells, may contribute to the pathogenesis of PCOS via their ability to secrete an array of cytokines implicated in follicle growth. The aim of this study was to examine leukocyte subtypes in follicular phase ovaries and to quantify cytokine and chemokine mRNA expression in follicular fluid cells obtained at the time of oocyte retrieval before IVF in women with and without PCOS.

METHODS

Ovaries were immunostained for various leukocyte markers [CD3, CD4, CD14, CD15, CD45, CD45RA, CD45RO, CD57 and major histocompatibility complex (MHC) class II]. In addition, follicular fluid cells were subjected to quantitative RT-PCR to evaluate colony-stimulating factor-1 (CSF-1), granulocyte-macrophage (GM)-CSF, interleukins (IL-1beta, IL-6, IL-8 and IL-10), monocyte chemotactic protein (MCP-1) and tumour necrosis factor (TNFalpha) mRNA expression relative to beta-actin.

RESULTS

CD45RO+ cells (activated/memory T lymphocytes) were reduced by 60% in the theca layer of follicles from PCOS women. The relative abundance of macrophages and neutrophils was unchanged. Cytokine and chemokine mRNA transcripts examined were not affected by PCOS status. There was an association between high BMI and high TNFalpha and low IL-6 mRNA expression in follicular cells. IL-6 expression was higher in women who subsequently achieved pregnancy.

CONCLUSIONS

T lymphocytes potentially play a role in the local pathological mechanisms of PCOS. Further studies are required to identify their contribution to the aetiology of this common condition.

242. LIF expression is induced in the mouse oviduct following activation by seminal factors

A precisely regulated sequence of molecular and cellular changes occurs in the female reproductive tract in early pregnancy to facilitate development of the embryo and its successful implantation. Cytokine–leukocyte networks are integral in the tissue remodelling and immuno-regulatory processes underpinning successful implantation. Seminal factors are implicated in activating expression of cytokine genes and inflammatory leukocyte recruitment in the uterus, but whether semen-induced effects extend to the oviduct to influence blastocyst development has not been examined. The aim of this study was to quantitate the expression of mRNA encoding epidermal growth factor (EGF), granulocyte-macrophage colony-stimulating factor (GM-CSF), heparin-binding epidermal growth factor-like growth factor (HB-EGF), insulin-like growth factor (IGFII), leukaemia inhibitory factor (LIF), tumour necrosis factor (TNFα), transforming growth factor (TGFα) and TGFβ from oviducts collected from mice at oestrus and on day 1 of pregnancy, after mating with intact, seminal plasma deficient (svx) and vasectomised (vas) mice. Total RNA was extracted, DNAse treated, reverse transcribed into cDNA, and quantified by real-time PCR using SYBR Green chemistry. All cytokine-specific primers were designed using GenBank sequences and data were normalised to β-actin mRNA expression. Expression of LIF mRNA was induced following mating with intact or vas males, but not svx males, showing that LIF mRNA is induced by factors present in seminal plasma. mRNAs encoding EGF, GM-CSF, HB EGF, IGFII, TNFα, TGFα and TGFβ were all detected in oviduct cDNA collected from oestrus and day 1 mice. These data support the proposal that cytokine-leukocyte networks shown previously to be operative in the uterus extend to the oviduct, and are influenced by exposure to seminal plasma at mating. The cytokines expressed in the oviduct during early pregnancy are likely to be key regulators of embryo growth and development.

Seminal plasma regulates endometrial cytokine expression, leukocyte recruitment and embryo development in the pig

In pigs, uterine exposure to the constituents of semen is known to increase litter size but the underlying physiological mechanisms remain undefined. Studies in rodents and humans implicate immune modulating moieties in seminal plasma as likely candidates, acting through enhancing the receptivity of the female tract. In this study, the acute and longer term effects of seminal plasma on cytokine expression and leukocyte abundance in the pig endometrium during early pregnancy have been characterised. The reproductive tracts of gonadotrophin-primed pre-pubertal gilts treated with intrauterine infusions of either pooled seminal plasma or phosphate-buffered saline (PBS) were retrieved at 34 h, or on day 5 and day 9 after treatment. Seminal plasma elicited an endometrial inflammatory infiltrate comprised of predominantly macrophages and major histocompatibility complex class II+-activated macrophages and dendritic cells. The abundance of these cells was greatest at the pre-ovulatory (34 h) time-point and their increase relative to PBS-treated tissues was maintained until day 9 after seminal plasma treatment. Seminal plasma induced the expression of the cytokines, granulocyte macrophage colony-stimulating factor, interleukin-6 and monocyte chemoattractant protein-1, and the eicosanoid-synthesising enzyme cyclo-oxygenase-2. Expression was maximal 34 h after treatment but altered expression patterns as a consequence of seminal plasma induction persisted through early pregnancy. These changes were accompanied by altered dynamics in pre-implantation embryo development with an increase in the number of embryos and in their viability after seminal plasma treatment. Together, these findings implicate factors in seminal plasma in programming the trajectory of uterine cytokine expression and leukocyte trafficking during early pregnancy and in regulating pre-implantation embryo development in the pig.

226.Regulated expression of adhesion and anti-adhesion molecules in mouse endometrium during early pregnancy

To implant and establish the connections that are vital for further development, the early embryo must attach to and then breech the barrier posed by the epithelium of the maternal tract. Expression of adhesion and anti-adhesion molecules in the luminal epithelium of the endometrium are thought to fluctuate in a temporal pattern to 'frame' the implantation site, with their expression regulated by endocrine and paracrine factors. Anti-adhesion molecules, such as members of the mucin family, provide a barrier to implantation in sites or at times unsuitable for embryo development. Expression of adhesion molecules, or specific integrins, are thought to aid in the adhesion of the embryo, allowing it to induce changes in the underlying tissue promoting embryo invasion and pregnancy. The aim of this study was to quantitate the expression of mRNA encoding the integrins αυ, α4 and β3 and MUC1 and MUC4 from Day 0 (oestrous) to Day 4 of pregnancy (implantation) using quantitative real time RT-PCR. Uterine tissues were collected at oestrous and at Days 1, 2, 3 and 4 of pregnancy (Day 1 corresponding to the presence of a vaginal plug), total RNA was extracted, DNAse treated, reverse transcribed into cDNA, and quantified by real-time PCR using SYBR Green chemistry. All specific primers were designed using GenBank sequences and data were normalised to β-actin mRNA expression. Expression of MUC1 and MUC4 mRNAs was dramatically reduced, with mean values 20-fold and 100-fold less than at oestrous respectively, by Day 4 of pregnancy. In contrast, expression of mRNAs encoding integrins αυ, α4 and β3 was detected throughout early pregnancy. These data demonstrate that adhesion and anti-adhesion molecules are differentially expressed in the murine uterus during early pregnancy and may be key mediators in embryo implantation, promoting attachment of the embryo to the luminal epithelium in an environment conducive to embryo growth and development. Supported by a Clive & Vera Ramaciotti Project Grant to MJ Jasper.

261.Probiotic Lactobacillus in seminal plasma

Commensal bacteria of the Lactobacillus genus are implicated in beneficial 'probiotic' roles in the gut and other mucosal tissues. Their presence reduces the incidence of pathogenic infections, both passively and via production of antimicrobial substances, and through Toll-like receptor-mediated activation of cytokine expression in host tissues. Lactobacilli are present in the female reproductive tract but have not been examined in the male. This study aimed to investigate, by selective culture techniques and real-time quantitative PCR, the prevalence in boar seminal plasma of Lactobacilli compared with other pathogenic bacteria. Using acidified Rogosa Agar, Lactobacilli were cultured from 3/3 fresh semen samples and were found to be most prevalent in the first fraction of the ejaculate. For PCR, DNA was extracted from reference bacterial cultures and archived seminal plasma samples from 40 healthy boars. Bacterial species-specific primers targeting Lactobacillus 16s and 16s-23s rDNA sequences, and Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus-specific Sau3AI, oprL, and 16s rDNA genes respectively, were used in real-time PCR assays employing SYBRgreen (Applied Biosystems) technology. Lactobacilli were detected in 22/40 (55%) of seminal plasma samples, while pathogenic bacteria were detected in <10% of samples (Staphylococcus aureus, 1/40; Pseudomonas aeruginosa, 2/40; and Bacillus, 3/40). The Lactobacillus content of individual boars ranged from 1.5 to 15 × 106 cells/mL, and within boars, content varied within 30% of the mean value in successive samples over a 6-month period. We conclude that Lactobacilli are present in abundance in boar seminal plasma compared to other potentially pathogenic bacteria. These bacteria may protect the male tract from pathogen infection, and after ejaculation, may influence the female immune response to male antigens. Ongoing studies will investigate whether Lactobacilli abundance in seminal plasma correlates with boar fertility, and examine the potential value of improving reproductive performance in pigs and other species by administration of probiotic agents.

Granulocyte-macrophage colony-stimulating factor promotes glucose transport and blastomere viability in murine preimplantation embryos

Granulocyte-macrophage colony-stimulating factor (GM-CSF) secretion from epithelial cells lining the female reproductive tract is induced during early pregnancy by ovarian steroid hormones and constituents of seminal plasma. In this study we have investigated the influence of GM-CSF on development of preimplantation mouse embryos. Blastocyst-stage embryos were found to specifically bind (125)I-GM-CSF and analysis of GM-CSF mRNA receptor expression by reverse transcriptase-polymerase chain reaction indicated expression of the low-affinity alpha subunit of the GM-CSF receptor, but not the affinity-converting beta subunit (beta(c)), or GM-CSF ligand. GM-CSF receptor mRNA was present in the fertilized oocyte and all subsequent stages of development, and in blastocysts it was expressed in both inner cell mass and trophectoderm cells. In vitro culture of eight-cell embryos in recombinant GM-CSF accelerated development of blastocysts to hatching and implantation stages, with a maximum response at a concentration of 2 ng/ml (77 pM). Blastocysts recovered from GM-CSF-null mutant (GM-/-) mice on Day 4 of natural pregnancy or after superovulation showed retarded development, with the total cell number reduced by 14% and 18%, respectively, compared with GM+/+ embryos. Blastocysts generated in vitro from two-cell GM-/- and GM+/+ embryos were larger when recombinant GM-CSF was added to the culture medium (20% and 24% increases in total cell numbers in GM+/+ and GM-/- blastocysts, respectively). Incubation of blastocysts with recombinant GM-CSF elicited a 50% increase in the uptake of the nonmetabolizable glucose analogue, 3-O-methyl glucose. In conclusion, these data indicate that GM-CSF signaling through the low-affinity GM-CSF receptor in blastocysts is associated with increased glucose uptake and enhanced proliferation and/or viability of blastomeres. Together, the findings implicate a physiological role for maternal tract-derived GM-CSF in targeting the preimplantation embryo, and suggest that defective blastocyst development contributes to compromised pregnancy outcome in GM-CSF-null mutant mice.

Increased adhesiveness in cultured endometrial-derived cells is related to the absence of moesin expression

Human endometrial epithelial cells (EECs) are nonadhesive for embryos throughout most of the menstrual cycle. During the so-called implantation window, the apical plasma membrane of EECs acquire adhesive properties by undergoing a series of morphological and biochemical changes. The human endometrial-derived epithelial cell line, RL95-2, serves as an in vitro model for receptive uterine epithelium because of its high adhesiveness for trophoblast-derived cells. In contrast, the HEC-1-A cell line, which displays poor adhesive properties for trophoblast cells, is considered to be less receptive. The ezrin, radixin, and moesin protein family members, which are present underneath the apical plasma membrane, potentially act to link the cytoskeleton and membrane proteins. In the present study, we have further investigated the adhesive features in these two unrelated endometrial-derived cell lines using an established in vitro model for embryonic adhesion. We have also analyzed the protein pattern and mRNA expression of ezrin and moesin in RL95-2 cells versus HEC-1-A cells. The results demonstrate that RL95-2 cells were indeed more receptive (81% blastocyst adhesion) compared with HEC-1-A cells (46% blastocyst adhesion). An intermediate adhesion rate was found in primary EECs cultured on extracellular matrix gel, thus allowing a partial polarization of these cells (67% blastocyst adhesion). Furthermore, we found that moesin was absent from RL95-2 cells. In contrast, ezrin is expressed in both cell lines, yet it is reduced in adherent RL95-2 cells. Data are in agreement with the hypothesis that uterine receptivity requires down-regulation or absence of moesin, which is a less-polarized actin cytoskeleton.

Characterization of ovarian function in granulocyte-macrophage colony-stimulating factor-deficient mice

During the estrous cycle and early pregnancy, lymphohemopoietic cytokines and chemokines contribute to the regulation of ovarian function by orchestrating the recruitment and activation of leukocytes associated with the ovulatory follicle and corpus luteum. The purpose of this study was to investigate the physiological role of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the ovary, utilizing mice genetically deficient in GM-CSF. Our results show that the mean duration of the estrous cycle in GM-CSF-deficient (GM-/-) mice was extended by 1.5 days (mean +/- SE, 4.9 +/- 0.3 vs. 6.5 +/- 0.5 days for GM+/+ and GM-/- mice, respectively). Similar ovulation rates were observed in immature superovulated mice (31.8 +/- 7.7 vs. 28.9 +/- 6.4 oocytes per mouse) and adult naturally cycling mice (10.4 +/- 0.8 vs. 10.3 +/- 0.8 oocytes per mouse). Furthermore, comparable numbers of oocytes were released from GM+/+ and GM-/- ovaries in an in vitro perfusion model. However, ovaries in pregnant GM-/- mice were found to comprise fewer cells and synthesize less progesterone (141.6 +/- 10.3 vs. 116.5 +/- 6 nM plasma), although the duration of pseudopregnancy was unaltered by GM-CSF deficiency (11.0 +/- 0.2 vs. 11.0 +/- 0.5 days). Immunohistochemical staining of leukocytes in the ovary during the periovulatory period indicated that the size and composition of ovarian leukocyte populations were unaltered in the absence of GM-CSF. However, an effect of GM-CSF deficiency on the activation phenotype of ovarian leukocytes was indicated by a 57% increase in mean secretion of nitric oxide in in vitro-perfused GM-/- ovaries, and diminished major histocompability complex (MHC) class II (Ia) expression in ovarian macrophages and/or dendritic cells (30.5 +/- 7. 2% vs. 9.1 +/- 1.8% positive stain in GM+/+ and GM-/- ovaries, respectively). Furthermore, ovarian macrophages and neutrophils were diminished in number after parturition, with significantly decreased CD11b+ (Mac-1) staining in the stromal region of postpartum GM-/- ovaries (6.7 +/- 0.6 vs. 3.6 +/- 0.7% positive stain). In summary, GM-CSF does not appear to be essential for ovarian function but may play a role in fine-tuning the activation status and adhesive properties of ovarian myeloid leukocytes. Aberrant activation of these cells appears to compromise the luteinization process and the steroidogenic capacity of the corpus luteum during early pregnancy in GM-CSF-deficient mice.

Granulocyte-macrophage colony-stimulating factor: presence in human follicular fluid, protein secretion and mRNA expression by ovarian cells

In recent years it has become evident that a leukocyte-cytokine network contributes to the paracrine regulation of ovarian function. The objectives of this study were to examine the presence of a potent lympho-haemopoietic cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF), in tissues and fluids from human ovaries. In a prospective study, follicular fluid and plasma were collected from naturally cycling women and women undergoing hyperstimulation for in-vitro fertilization (IVF). Granulosa-lutein cells were collected at the time of oocyte recovery for IVF and corpora lutea were collected at the time of hysterectomy for non-ovarian reasons. Culture supernatants from ovarian cell and tissue cultures were harvested on completion of a 48 h incubation. Immunoactive GM-CSF was measured by enzyme-linked immunosorbent assay, and was found to be present at statistically significantly higher levels in follicular fluid (8.9 +/- 0.7 pg/ml) and plasma (11.3 +/- 0.8 pg/ml) of women undergoing hyperstimulation compared to follicular fluid (5.3 +/- 0.3 pg/ml) and plasma (7.1 +/- 0.5 pg/ml) from naturally cycling women. Immunoactive GM-CSF was also detected in culture supernatants of granulosa-lutein cells (47.6 pg/10(5) cells), early luteal phase corpora lutea (0.52 pg/microgram DNA) and mid-luteal phase corpora lutea (0.98 pg/microgram DNA). Furthermore, transcripts for GM-CSF, and both the alpha and beta subunits of the GM-CSF receptor, were detected by reverse transcription polymerase chain reaction (RT-PCR) in granulosa-lutein cell culture preparations and corpora lutea collected during the early, mid- and late luteal phase of the menstrual cycle. These results show that GM-CSF is expressed and secreted by cells within the human ovary, and, together with the finding of expression of mRNA for GM-CSF receptor, suggest a role for GM-CSF in the local regulation of ovarian events.