Placental insufficiency and heavier placentas in sheep after suppressing CXCL12/CXCR4 signaling during implantation†

During implantation, trophoblast cell invasion and differentiation is predominantly important to achieving proper placental formation and embryonic development. The chemokine, C-X-C motif chemokine ligand 12 (CXCL12) working through its receptor C-X-C motif chemokine receptor 4 (CXCR4) is implicated in implantation and placentation but precise roles of this axis are unclear. Suppressing CXCL12/CXCR4 signaling at the fetal-maternal interface in sheep reduces trophoblast invasion, disrupts uterine remodeling, and diminishes placental vascularization. We hypothesize these negative impacts during implantation will manifest as compromised fetal and placental growth at midgestation. To test, on day 12 postbreeding, osmotic pumps were surgically installed in 30 ewes and delivered intrauterine CXCR4 inhibitor or saline for 7 or 14 days. On day 90, fetal/maternal tissues were collected, measured, weighed, and maternal (caruncle) and fetal (cotyledon) placenta components separated and analyzed. The objectives were to determine if (i) suppressing CXCL12/CXCR4 during implantation results in reduced fetal and placental growth and development and (ii) if varying the amount of time CXCL12/CXCR4 is suppressed impacts fetal/placental development. Fetal weights were similar; however greater placental weight and placentome numbers occurred when CXCL12/CXCR4 was suppressed for 14 days. In caruncles, greater abundance of fibroblast growth factor 2, vascular endothelial growth factor A, vascular endothelial growth factor A receptor 1 (FLT-1), and placental growth factor were observed after suppressing CXCL12/CXCR4. Similar results occurred in cotyledons except less vascular endothelial growth factor in 7 day group and less fibroblast growth factor in 14 day group. Our data underscore the importance of CXCL12/CXCR4 signaling during placentation and provide strong evidence that altering CXCL12-mediated signaling induces enduring placental effects manifesting later in gestation.

PS-2 Early Intrauterine Suppression of CXCL12-CXCR4 Alters Expression of Placental Inflammatory Profile at Mid-to-Late Gestation

A proper balance of inflammatory cytokines at the fetal-maternal interface is crucial for successful embryo implantation and placental formation. Chemokine ligand 12 (CXCL12) and receptor CXCR4 are expressed by fetal and maternal placental tissues and implicated in cytokine synthesis. However, mechanisms controlling the axis and placental inflammatory profile are not well characterized. Using an in-vivo sheep model, we previously demonstrated suppressing CXCL12-CXCR4 signaling at the fetal-maternal interface during implantation yielded dysregulated production of inflammatory cytokines in the placenta. Our objective was to determine if disrupting the cytokine profile during implantation alters the placental inflammatory profile at mid-to-late gestation. Day 12 post-breeding, osmotic pumps were surgically installed in 37 ewes to deliver CXCR4 inhibitor (1.5X dose, n = 8; 1X dose, n = 8; 3X dose, n = 8) or saline (n = 13) into the uterine lumen ipsilateral to the corpus luteum for 14 days. On days 90 and 135 of gestation, placental tissues were collected; maternal (caruncle) and fetal (cotyledon) placenta components were then separated and analyzed. Real-time qPCR was used to measure gene expression of pro-inflammatory cytokines tumor necrosis factor (TNF), interferon-γ (IFNγ), interleukin-12 (IL12), and anti-inflammatory cytokines interleukin-10 (IL10) and transforming growth factor-β (TGFβ). Gene expression for TGFβ from tissues ipsilateral to the pump on day 90 increased (P < 0.03) in caruncles from 3x treated ewes compared to control ewes while IL10 mRNA decreased (P < 0.02) in cotyledons from 1.5x compared to 3x treatment. Furthermore, analysis of day 135 1x treated ewes showed greater expression (P < 0.03) of IL12 in caruncles ipsilateral compared to contralateral of the pump; meanwhile IL10 showed decreased expression (P < 0.02) in cotyledons ipsilateral compared to contralateral of the pump. High levels of TGFβ, IFNγ (whose production is promoted by increased IL12), and TNF along with decreased levels of IL10 have been associated with preeclampsia in women. The changes in gene expressions of ovine immune cytokines with a disrupted CXCL12-CCR4 axis may be related to preeclamptic events. Ultimately, modulating CXCL12-induced actions is a novel approach to manipulating the fetal-maternal environment when most pregnancy losses occur and may reveal methods to improve reproductive success and fetal health in livestock.

PSI-2 Disruption of CXCL12-CXCR4 Axis at Fetal-Maternal Interface During Implantation Alters Ovine Angiogenic Expression at Mid-to-Late Gestation

Placental dysfunction originates during placental development, specifically the events of placentation. Vascularization is a key component of placentation due to its role in fetal-maternal exchange. Cytokines are regulators of placental development; signaling of chemokine ligand 12 (CXCL12) and its receptor (CXCR4) drives placental vascularization. Utilizing an in vivo sheep model, we demonstrated that suppressing CXCL12-CXCR4 signaling at the fetal-maternal interface reduces placental vascularization. We hypothesized these negative impacts early in gestation would result in compromised placental development and vascularization at mid to late gestation. On day 12 post-breeding, osmotic pumps were surgically installed in 37 ewes and delivered either CXCR4 inhibitor (AMD3100) at 1x dose (n = 8),1.5X dose (n = 8), or 3X dose (n = 8) or saline (n = 13) into the uterine lumen ipsilateral to the corpus luteum for 14 days. On day 90 and day 135 placental tissues were collected and maternal (caruncle) and fetal (cotyledon) placenta components were separated and analyzed. Gene expression of angiogenic factors were analyzed using Real-time qPCR. Gene expression was significantly altered by AMD3100 treatment for the vascular endothelial growth factor receptors (FLT-1 and KDR) primarily in day 90 placenta contralateral to the corpus luteum. Significant decreases in KDR were seen in 3x compared to control (P < 0.03), 3x compared to 1.5x (P < 0.008), and 3x contralateral compared to ipsilateral (P < 0.01); however, FLT-1 significantly increased (P < 0.02) from control to 1.5x. Day 90 caruncle tissue had significant increases in FLT-1 from control to 3x (0.02), 1.5x to 3x (P < 0.03); however, 1.5x treatment FLT-1 significantly decreased (P < 0.02) ipsilateral to contralateral. Fibroblast growth factor 2 increased in both contralateral 3x compared to control cotyledon (P < 0.03) and caruncle (P < 0.03). Our data underscore the importance of CXCL12-CXCR4 signaling during placentation and provide strong evidence that altering CXCR4-mediated signaling during early placentation induces enduring effects altering vascular development later in gestation. A greater understanding of CXCL12/CXCR4 functions may reveal methods to improve reproductive success and fetal health.

PSIII-1 Late-Breaking: Fighting Fetal Morbidity at the Fetal-Maternal Interface One Chemokine Access at a Time

Improper placentation is the root cause to intrauterine growth restriction (IUGR) and fetal mortality in livestock. This study aims to further characterize the importance of the C-X-C motif chemokine receptor 4 (CXCR4) and its ligand CXCL12 on placentation and fetal growth through potential impacts on the insulin-like growth factors (IGF) and their binding proteins (IGFBP1-3). CXCR4 and CXCL12 are implicated in placentation though the exact roles are unclear. The peptides insulin-like growth factors 1 and 2 have impacts on fetal growth, placental development, and trophoblast differentiation and if the IGFs are down regulated, a corresponding decrease in placenta and fetus size has been observed. The roles of the IGFs and their binding proteins in disease states like IUGR are not completely known but studies have demonstrated them to be contributing factors. Using an in-vivo sheep model we surgically inserted osmotic pumps on day 12 (d12) of gestation ipsilateral to the corpus luteum to deliver treatments into the uterus of bred ewes. Pumps delivered either saline (control) or AMD3100, the CXCR4 inhibitor at a 1x, 1.5x, or 3x dose into the uterine lumen over the course of 14 days. Our objective was to determine if disrupting the CXCL12/CXCR4 axis during implantation alters the expression of IGFs and their binding proteins in the placenta at mid and late gestation. At midgestation (d90) and late gestation (d135) placental and fetal samples were obtained for analysis. Of the targets tested, mRNA expression was significantly decreased by AMD3100 treatment for both IGF-1 (P = 0.05) and IGF-2 (P = 0.02) compared to control primarily in maternal placenta tissues on d135. For fetal tissue samples, d90 mRNA expression for IGF-1 (P = 0.04) IGFBP-2 (P = 0.02) and IGFBP-3 (P = 0.03) increased in the 3x AMD3100 treated group compared to the control while in d135 samples, IGF-1was significantly decreased (P = 0.04) by the 1x treatments compared to control. Our preliminary data show an importance of the CXCL12- CXCR4 signaling on placentation and that impairment of this axis may alter IGFs in multiple tissue types later in gestation. Insights into this chemokine axis will lead to a greater understanding of placental development and its importance to the health of mother and offspring.

PSI-9 Disrupting Cxcl12-Cxcr4 Chemokine Axis at the Fetal-Maternal Interface During Implantation Results in Altered Expression of Angiogenic and Insulin-Like Growth Factors in Ovine Placenta Midgestation

Placental dysfunction is a fundamental cause of intrauterine growth restriction, and fetal morbidity and mortality in livestock. Though causes of placental dysfunction are not well characterized, origin of disease transpires during placental development (placentation). The C-X-C motif chemokine ligand 12 (CXCL12) working through its receptor CXCR4 is implicated in placentation but precise roles of this axis are unclear. Using an in vivo sheep model, we demonstrated that suppressing CXCL12-CXCR4 signaling at the fetal-maternal interface reduces placental vascularization. We hypothesized these negative impacts early in gestation would result in compromised placental development and vascularization at midgestation. To test, onday 12 post-breeding, osmotic pumps were surgically installed in 22 ewes and delivered either CXCR4 inhibitor (AMD3100) at 1.5X dose, (n=8) or 3X dose (n=8) or saline (n=6) into the uterine lumen ipsilateral to the corpus luteum for 14 days. On day 90 placental tissues were collected and maternal and fetal placenta components separated and analyzed. The objectives were to determine if suppressing CXCL12-CXCR4 actions at the fetal-maternal interface during implantation results in reduced placental and vascular development at midgestation. Gene expression for angiogenic factors and members of the insulin-like growth factor family were analyzed using Real-time qPCR. Of the targets tested, mRNA expression was significantly altered by AMD3100 treatment for the vascular endothelial growth factor receptors (FLT-1 and KDR) primarily in maternal placenta. Expression of insulin-like growth factors 1 and 2, IGF-binding protein 3, and placental lactogen were significantly altered in fetal placenta with AMD3100 treatment compared to control. Our preliminary data underscore the importance of CXCL12-CXCR4 signaling during placentation and provide strong evidence that altering CXCL12-mediated signaling during early placentation induces enduring placental effects manifesting later in gestation. A greater understanding of CXCL12/CXCR4 functions may reveal methods to improve reproductive success and fetal health.

PSII-A-11 Suppressing the Cxcl12-Cxcr4 Chemokine Axis at the Fetal-Maternal Interface During Implantation Results in Altered Expression of Inflammatory Cytokines in Ovine Placenta at Midgestation

A proper balance of pro and anti-inflammatory cytokines at the fetal-maternal interface is crucial for successful embryo implantation and placental formation (placentation) during early gestation. However, mechanisms controlling this inflammatory profile are not well characterized. The C-X-C motif chemokine ligand 12 (CXCL12) and its receptor CXCR4 are expressed by fetal and maternal placental tissues and implicated in cytokine synthesis; roles of this axis during placentation are unclear. Using an in vivo sheep model, we demonstrated that suppressing CXCL12-CXCR4 signaling at the fetal-maternal interface during implantation results in dysregulated production of inflammatory cytokines in the placenta. The objective of the current study was to determine if the disrupted cytokine profile from suppressing CXCL12-CXCR4 signaling early in gestation would result in altered placental inflammatory profile at midgestation. On day 12 post-breeding, osmotic pumps were surgically installed in 37 ewes and delivered either CXCR4 inhibitor (AMD3100) at 1X dose, (n=8), 1.5X, (n=8), or 3X, (n=8) or saline (n=13) into the uterine lumen ipsilateral to the corpus luteum for 14 days. On days 90 and 135, placental tissues were collected, and maternal and fetal placenta components separated and analyzed. Gene expression for select cytokines were analyzed in the placenta using Real-time qPCR. On day 90, mRNA expression was significantly altered by AMD3100 treatment for tumor necrosis factor (TNF), interleukin 12 (IL-12), and transforming growth factor beta (TGFB) in fetal placenta. Expression of TGFB in fetal placenta was also altered by AMD3100 treatment compared to control on day 135 whereas IL-12 expression was significantly altered in maternal placenta on day 135. In conclusion, modulating CXCL12-induced actions is a novel approach to manipulating the fetal-maternal environment when most pregnancy losses occur. Increasing our understanding of CXCL12-induced actions controlling the placental inflammatory environment will hopefully reveal methods to improve reproductive success and fetal health in livestock.

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.

Inhibition of the C-X-C Motif Chemokine 12 (CXCL12) and Its Receptor CXCR4 Reduces Utero-Placental Expression of the VEGF System and Increases Utero-Placental Autophagy

The placenta, a unique organ that only develops during pregnancy, is essential for nutrient, oxygen, and waste exchange between offspring and mother. Yet, despite its importance, the placenta remains one of the least understood organs and knowledge of early placental formation is particularly limited. Abnormalities in placental development result in placental dysfunction or insufficiency whereby normal placental physiology is impaired. Placental dysfunction is a frequent source of pregnancy loss in livestock, inflicting serious economic impact to producers. Though the underlying causes of placental dysfunction are not well-characterized, initiation of disease is thought to occur during establishment of functional fetal and placental circulation. A comprehensive understanding of the mechanisms controlling placental growth and vascularization is necessary to improve reproductive success in livestock. We propose chemokine C-X-C motif ligand 12 (CXCL12) signaling through its receptor CXCR4 functions as a chief coordinator of vascularization through direct actions on fetal trophoblast and maternal endometrial and immune cells. To investigate CXCL12–CXCR4 signaling on uteroplacental vascular remodeling at the fetal–maternal interface, we utilized a CXCR4 antagonist (AMD3100). On day 12 post-breeding in sheep, osmotic pumps were surgically installed and delivered either AMD3100 or saline into the uterine lumen ipsilateral to the corpus luteum for 14 days. On day 35 of ovine pregnancy, fetal/placental and endometrial tissues were collected, snap-frozen in liquid nitrogen, and uterine horn cross sections were preserved for immunofluorescent analysis. Suppressing CXCL12–CXCR4 at the fetal–maternal interface during initial placental vascularization resulted in diminished abundance of select angiogenic factors in fetal and maternal placenta on day 35. Compared to control, less vascular endothelial growth factor (VEGF) and VEFG receptor 2 (KDR) were observed in endometrium when CXCL12–CXCR4 was diminished. Less VEGF was also evident in fetal placenta (cotyledons) in ewes receiving AMD3100 infusion compared to control. Suppressing CXCL12–CXCR4 at the fetal–maternal interface also resulted in greater autophagy induction in fetal and maternal placenta compared to control, suggestive of CXCL12–CXCR4 impacting cell survival. CXCL12–CXCR4 signaling may govern placental homeostasis by serving as a critical upstream mediator of vascularization and cell viability, thereby ensuring appropriate placental development.

CXCR4 signaling at the fetal-maternal interface may drive inflammation and syncytia formation during ovine pregnancy†

Early pregnancy features complex signaling between fetal trophoblast cells and maternal endometrium directing major peri-implantation events including localized inflammation and remodeling to establish proper placental development. Proinflammatory mediators are important for conceptus attachment, but a more precise understanding of molecular pathways regulating this process is needed to understand how the endometrium becomes receptive to implantation. Both chemokine ligand 12 (CXCL12) and its receptor CXCR4 are expressed by fetal and maternal tissues. We identified this pair as a critical driver of placental angiogenesis, but their additional importance to inflammation and trophoblast cell survival, proliferation, and invasion imply a role in syncytia formation at the fetal-maternal microenvironment. We hypothesized that CXCL12 encourages both endometrial inflammation and conceptus attachment during implantation. We employed separate ovine studies to (1) characterize endometrial inflammation during early gestation in the ewe, and (2) establish functional implications of CXCL12 at the fetal-maternal interface through targeted intrauterine infusion of the CXCR4 inhibitor AMD3100. Endometrial tissues were evaluated for inflammatory mediators, intracellular signaling events, endometrial modifications, and trophoblast syncytialization using western blotting and immunohistochemistry. Endometrial tissue from ewes receiving CXCR4 inhibitor demonstrated dysregulated inflammation and reduced AKT and NFKB, paired with elevated autophagic activity compared to control. Immunohistochemical observation revealed an impairment in endometrial surface remodeling and diminished trophoblast syncytialization following localized CXCR4 inhibition. These data suggest CXCL12-CXCR4 regulates endometrial inflammation and remodeling for embryonic implantation, and provide insight regarding mechanisms that, when dysregulated, lead to pregnancy pathologies such as intrauterine growth restriction and preeclampsia.

CXCR4 signaling at the ovine fetal-maternal interface regulates vascularization, CD34+ cell presence, and autophagy in the endometrium†

Placenta development is characterized by extensive angiogenesis and vascularization but if these processes are compromised placental dysfunction occurs, which is the underlying cause of pregnancy complications such as preeclampsia and intrauterine growth restriction. Dysregulation of placental angiogenesis has emerged as one of the main pathophysiological features in the development of placental insufficiency and its clinical consequences. The signaling axis initiated by chemokine ligand 12 (CXCL12) and its receptor CXCR4 stimulates angiogenesis in other tissues, and may be central to placental vascularization. We hypothesized that CXCL12-CXCR4 signaling governs the pro-angiogenic placental microenvironment by coordinating production of central angiogenic factors and receptors and regulates endometrial cell survival essential for placental function and subsequent fetal longevity. The CXCR4 antagonist, AMD3100, was used to elucidate the role of CXCL12-CXCR4 signaling regarding uteroplacental vascular remodeling at the fetal-maternal interface. On day 12 postbreeding, osmotic pumps were surgically installed and delivered either AMD3100 or PBS into the uterine lumen ipsilateral to the corpus luteum. On day 20, endometrial tissues were collected, snap-frozen in liquid nitrogen, and uterine horn cross sections preserved for immunofluorescent analysis. In endometrium from ewes receiving AMD3100 infusion, the abundance of select angiogenic factors was diminished, while presence of CD34+ cells increased compared to control ewes. Ewes receiving AMD3100 infusion also exhibited less activation of Akt/mTOR signaling, and elevated LC3B-II, a marker of cellular autophagy in endometrium. This study suggests that CXCL12-CXCR4 signaling governs placental homeostasis by serving as a critical upstream mediator of vascularization and cell viability, thereby ensuring appropriate placental development.

Abstract P6-05-03: Exogenous steroid hormone exposure and the biology of lobular breast cancer

Introduction. Invasive lobular carcinoma (ILC) accounts for 10-15% of breast cancer diagnoses and is characterized by a high rate of estrogen and progesterone receptor (ER and PR) expression, low rate of HER2 amplification, and a defining lack of e-cadherin expression. Multiple population-based, observational studies have shown that the risk of ILC is significantly elevated with the intake of combined estrogen/progestin (E+P) hormone replacement therapy (HRT) but not with estrogen-alone (E alone) HRT. In addition, recent studies have revealed that ILCs might respond differently to hormone therapies than IDCs. We sought to understand the influence of exogenous hormone exposure in the form of HRT on biological pathways in ILCs compared to the more common histologic subtype, ER+ invasive ductal carcinoma (IDC).

Specimens and Methods. We assessed 297 ER+/HER2- FFPE breast carcinomas, 165 IDCs and 132 ILCs, previously collected from an epidemiological study of HRT use and breast cancer in post-menopausal women. These tumors were characterized for histopathological features and protein marker expression by immunohistochemistry along with the extensive clinical and demographic data, including HRT use, collected in the parent study. Using the Nanostring nCounter assay, we measured expression of ~1000 genes representing canonical cancer-promoting pathways and steroid hormone-associated pathways to determine the relationship between HRT use and pathway alterations in ER+ breast cancer subtypes.

Results. From the histopathological assessment, we observed that ILCs had lower overall lymphocyte response than IDCs (p=0.005), but HRT use shifted the lymphocyte response higher than what was observed in ILCs from never/former HRT users (p=0.002). In the gene expression analysis, we found that IDCs and ILCs have distinct expression profiles after adjusting for HRT use, including genes in cell cycle, steroid hormone-response pathways, and cytokine/cytokine receptor interactions, with increased signaling seen in the IL6/12-like family. When comparing gene expression between the HRT-use groups, adjusting for histology, we observed that E+P and E alone are both associated with down-regulation of cell cycle and DNA repair genes compared to the never/former use group. When we focused on expression patterns specific to progestin exposure, (i.e., E+P versus all others), we found decreased expression of genes related to DNA replication initiation and G1/S transition and WNT4. Unsupervised hierarchical clustering revealed additional subgroups within each histologic subtype including a group of low-grade, low-proliferating IDCs enriched for E+P exposure, which clusters with the majority of the ILCs. While many gene expression changes with HRT use are shared across the tumors, we observed alterations that are specific to either ILCs or IDCs, suggesting different steroid hormone-responsive pathways between the subtypes.

Conclusions. Our study demonstrates there are potentially specific pathways differentially activated between ILCs and IDCs dependent on the type of hormone exposure. Further, while our study is focused on tumor molecular pathways modulated in response to HRT use, steroid hormone exposure can come from multiple sources, and we propose that the results from this study can provide insight into hormonally-driven breast cancers that develop with excess estrogen and/or progesterone exposure. This could have implications in clinical management of ILCs and IDCs that arise in HRT users.

Citation Format: Jamie Guenthoer, Isaac C Jenkins, Beti Thompson, Mei-Tzu C Tang, Nancy E Davidson, Ryan L Ashley, Christopher I Li, Li Hsu, Peggy L Porter. Exogenous steroid hormone exposure and the biology of lobular breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-05-03.

Intrauterine inhibition of chemokine receptor 4 signaling modulates local and systemic inflammation in ovine pregnancy

PROBLEM

Chemokines help coordinate inflammation within the fetal-maternal microenvironment during gestation. The chemokine CXCL12 signaling through its receptor CXCR4 regulates inflammatory activity, but this phenomenon is not well understood during pregnancy, and there are no reports exploring the role of this pair in peripheral immune tolerance during gestation. Herein, we hypothesize that intrauterine CXCL12-CXCR4 signaling governs local and systemic immunomodulatory dynamics during early gestation in ewes.

METHOD OF STUDY

Osmotic pumps were surgically installed for intrauterine infusion of a CXCR4 inhibitor, AMD3100, beginning on day 12 post-breeding in sheep. Endometrial tissues were collected on day 35 of gestation and evaluated for inflammatory potential, Akt pathway activation, and autophagy induction. Demonstrative of peripheral immune activity, levels of select cytokines were assessed in daily blood samples collected throughout the study, as well as in corpus luteum and spleen on day 35.

RESULTS

Anti-inflammatory IL10 was primarily localized to endometrial glandular epithelium with lower abundance when CXCR4 was antagonized. Inhibition of CXCR4 at the fetal-maternal interface resulted in less activation of Akt in endometrium, while evidence of autophagy induction was greater. Corpora lutea from ewes receiving intrauterine AMD3100 exhibited lower interferon-gamma (IFNG) expression. Blood inflammatory potential was differentially altered in a temporal fashion throughout infusion. IL10 abundance in spleen was greater following CXCR4 inhibition at the fetal-maternal interface, while IFNG was less.

CONCLUSION

Intrauterine CXCL12-CXCR4 signaling governs endometrial and systemic inflammation; disruption of this axis may have detrimental impacts on offspring and maternal health.

Neuropeptidome of the Hypothalamus and Pituitary Gland of Indicine × Taurine Heifers: Evidence of Differential Neuropeptide Processing in the Pituitary Gland before and after Puberty

Puberty in cattle is regulated by an endocrine axis, which includes a complex milieu of neuropeptides in the hypothalamus and pituitary gland. The neuropeptidome of hypothalamic-pituitary gland tissue of pre- (PRE) and postpubertal (POST) Bos indicus-influenced heifers was characterized, followed by quantitative analysis of 51 fertility-related neuropeptides in these tissues. Comparison of peptide abundances with gene expression levels allowed assessment of post-transcriptional peptide processing. On the basis of classical cleavage, 124 mature neuropeptides from 35 precursor proteins were detected in hypothalamus and pituitary gland tissues of three PRE and three POST Brangus heifers. An additional 19 peptides (cerebellins, PEN peptides) previously reported as neuropeptides that did not follow classical cleavage were also identified. In the pre-pubertal hypothalamus, a greater diversity of neuropeptides (25.8%) was identified relative to post-pubertal heifers, while in the pituitary gland, 38.6% more neuropeptides were detected in the post-pubertal heifers. Neuro-tissues of PRE and POST heifers revealed abundance differences ( p < 0.05) in peptides from protein precursors involved in packaging and processing (e.g., the granin family and ProSAAS) or neuron stimulation (PENK, CART, POMC, cerebellins). On their own, the transcriptome data of the precursor genes could not predict the neuropeptide profile in the exact same tissues in several cases. This provides further evidence of the importance of differential processing of the neuropeptide precursors in the pituitary before and after puberty.

In the ovine pituitary, CXCR4 is localized in gonadotropes and somatotropes and increases with elevated serum progesterone

The pituitary is the central endocrine regulator of reproduction and in addition to various hormones regulating its actions, other molecules, such as chemokines, influence pituitary physiology as well. Despite reports over 2 decades ago that chemokines regulate the pituitary, much of the basic biology discerning chemokine action in the pituitary is unclear. A small number of chemokines and their receptors have been localized to the pituitary, yet chemokine ligand 12 (CXCL12) and its receptor, CXCR4, have received the most attention as both are increased in human pituitary adenomas. This chemokine duo was also reported in normal human and rat pituitary, suggestive of a functional role and that this chemokine axis might function in pituitaries from other mammalian species. To date, reports of CXCL12 and CXCR4 in pituitary from livestock are lacking, and research on pituitary during pregnancy in any mammalian species is limited. Moreover, progesterone regulates CXCR4 expression in a tissue-dependent manner, but whether differing concentrations of progesterone reaching the pituitary modulate CXCL12 or CXCR4 is not known. To address these gaps, our first objective was to determine if CXCL12 and CXCR4 expression and protein abundance differ in sheep pituitary during early gestation (days 20, 25, and 30 of gestation) compared to nonpregnant ewes. The second objective was to determine if CXCL12 or CXCR4 production was altered in the ovine pituitary when circulating progesterone concentrations are elevated. The expression of CXCL12 messenger RNA decreased on day 20 of gestation compared to nonpregnant ewes; CXCL12 protein was similar across all days tested. In nonpregnant and pregnant ewes, CXCR4 was localized to somatotropes and gonadotropes on all days tested. Abundance of CXCR4 increased in the pituitary tissue of pregnant ewes with elevated circulating progesterone compared with pregnant ewes with normal circulating progesterone concentrations (control). The present study details CXCL12 and CXCR4 in normal ovine pituitary and reveals that gonadotropes and somatotropes may be regulated by CXCL12/CXCR4, underscoring this signaling axis as a potential new class of modulator in endocrine functions.

Inhibition of chemokine (C-X-C motif) receptor four (CXCR4) at the fetal-maternal interface during early gestation in sheep: alterations in expression of chemokines, angiogenic factors and their receptors

Chemokine (C-X-C motif) ligand 12 (CXCL12) and its receptor, chemokine (C-X-C motif) receptor 4 (CXCR4), are involved in significant biological processes associated with early pregnancy including increasing trophoblast invasion and stimulating placental vascularization. To further elucidate functions of CXCL12-CXCR4 signaling during early gestation, our objective was to inhibit CXCR4 in vivo using a CXCR4 antagonist, AMD3100. We hypothesized that inhibition of CXCR4 would negatively affect chemokine and angiogenic factor regulation imperative for placental development in sheep. Osmotic pumps containing PBS (control) or AMD3100 (CXCR4 antagonist) were surgically installed ipsilateral to the corpus luteum on d 12 of gestation and administered treatments directly into the uterine lumen. Maternal (caruncle and intercaruncle) and fetal membrane tissues were collected on d 23 of gestation and mRNA and protein expression were analyzed for vascular endothelial growth factor (VEGF), kinase insert domain receptor (KDR), fms related tyrosine kinase 1 (FLT1), fibroblast growth factor 2 (FGF2), angiopoietin 1 (ANGPT1), hypoxia inducible factor 1 ɑ subunit (HIF1A), CXCL12, and its corresponding receptors (CXCR4 and CXCR7). Immunohistochemical procedures were performed for analysis of CXCL12 and cell proliferation. In caruncle tissue ipsilateral to the pump, mRNA for KDR, ANGPT1, HIF1A, and CXCL12 increased (P < 0.05) in treated ewes compared to control, whereas caruncle tissue contralateral to the pump had increased expression (P < 0.05) of KDR, and CXCL12 in treated ewes. In fetal membrane, CXCR4 mRNA and protein decreased (P < 0.05), while VEGF protein decreased (P < 0.05) in caruncle and fetal membrane tissue from treated ewes. Results from this study highlight the importance of CXCL12-CXCR4 signaling at the fetal-maternal interface. Inhibiting this axis may disrupt typical regulation of angiogenic factors needed for placental development and embryo growth.

Citrullination regulates the expression of insulin-like growth factor-binding protein 1 (IGFBP1) in ovine uterine luminal epithelial cells

There are five peptidylarginine deiminase (PAD) isozymes designated as PADs 1, 2, 3, 4 and 6, and many are expressed in female reproductive tissues. These enzymes post-translationally convert positively charged arginine amino acids into neutral citrulline residues. Targets for PAD-catalyzed citrullination include arginine residues on histone tails, which results in chromatin decondensation and changes in gene expression. Some of the first studies examining PADs found that they are localized to rodent uterine epithelial cells. Despite these findings, the function of PAD-catalyzed citrullination in uterine epithelial cells is still unknown. To address this, we first examined PAD expression in uterine cross-sections from pregnant ewes on gestation day 25 (d25). Immunohistochemistry revealed that the levels of PADs 2 and 4 are robust in luminal and glandular epithelia compared with those of PADs 1 and 3. As PADs 2 and 4 have well-characterized roles in histone citrullination, we next hypothesized that PADs citrullinate histones in these uterine cells. Examination of caruncle lysates from pregnant ewes on gestation d25 and an ovine luminal epithelial (OLE) cell line shows that histone H3 arginine residues 2, 8, 17 and 26 are citrullinated, but histone H4 arginine 3 is not. Using a pan-PAD inhibitor, we next attenuated histone citrullination in OLE cells, which resulted in a significant decrease in the expression of insulin-like growth factor-binding protein 1 (IGFBP1) mRNA. As IGFBP1 is important for the migration and attachment of the trophectoderm to uterine endometrium, our results suggest that PAD-catalyzed citrullination may be an important post-translational mechanism for the establishment of pregnancy in ewes.

Progestin-mediated activation of MAPK and AKT in nuclear progesterone receptor negative breast epithelial cells: The role of membrane progesterone receptors

Progesterone (P4), a steroid produced during estrous cycles and gestation for maintenance of pregnancy, also plays key roles in breast development to allow lactation post-parturition. Progestins (P4 and related steroids) are also implicated in breast cancer etiology. Hormone replacement therapy containing both estrogen and progestins increases breast cancer incidence while estrogen hormone therapy lowers breast cancer risk. P4 signaling via nuclear P4 receptors (PRs) has been extensively studied in breast cancer, however, progestin signaling via non-classical membrane bound progestin receptors (MPRs and PGRMC1) remains unclear. Moreover, P4 metabolites and synthetic progestins may bind membrane progestin receptors. We hypothesized that PR-negative breast epithelial cells express non-classical progestin receptors, which activate intracellular signaling pathways differently depending on nature of progestin. Therefore, our objectives for the current study were to determine expression of MPRs and PGRMC1 in two PR-negative non-tumorigenic breast epithelial cell lines, assess progestin-mediated signaling and biological functions. We determined five MPR isoforms and PGRMC1 were present in MCF10A cells and all progestin receptors but MPRβ in MCF12A cells. MCF10A and MCF12A cells were treated with P4, select P4 metabolites (5αP and 3αHP), medroxyprogesterone acetate (MPA), or a specific MPR-Agonist (MPR-Ag) and phosphorylation of ERK, p38, JNK, and AKT was characterized following treatment. To our knowledge this is the first report of ERK and JNK activation in MCF10A and MCF12A cells with P4, P4 metabolites, MPA, and MPR-Ag. Activation of ERK and JNK in cells treated with MPR-Ag implicates MPRs may serve as the receptors responsible for their activation. In contrast, p38 activation varied with cell type and with progestin treatment. P4 and MPA promoted AKT phosphorylation in the MCF12A cell line only whereas no activation was observed in MCF10A cells. Interestingly, cellular proliferation increased in MCF10A cells treated with MPA or 5αP, while MPR-Ag tended to slightly decrease proliferation. Collectively, our data highlights the importance of investigating the effects of synthetic progestins in breast cancer biology. Our results add to the understanding that various progestins have on breast epithelial cells and underscores the importance of considering both membrane bound receptors and progestin type in breast cancer development.

Placental development during early pregnancy: Effects of embryo origin on expression of chemokine ligand twelve (CXCL12)

The aim was to localize chemokine ligand twelve (CXCL12) in sheep placental tissues during early gestation and after assisted reproductive technologies (ART). Uteri were collected from naturally (NAT) mated ewes and ewes receiving embryo transfer (ET), in vitro fertilization (IVF) or in vitro activation (IVA). CXCL12 was immunolocalized to endometrial stroma, glands, and trophoblast. Greater CXCL12 immunoreactivity was present in trophoblast on day 22 and 24 and in NAT ewes compared to IVF and IVA. Increased CXCL12 expression suggests CXCL12 promotes implantation and placentation. Decreased CXCL12 in IVF and IVA embryos, may compromise pregnancy establishment when utilizing ART methods.

Temporal Release, Paracrine and Endocrine Actions of Ovine Conceptus-Derived Interferon-Tau During Early Pregnancy

The antiviral activity of interferon (IFN) increases in uterine vein serum (UVS) during early pregnancy in sheep. This antiviral activity in UVS collected on Day 15 of pregnancy is blocked by anti-IFN-tau (anti-IFNT) antibodies. Conceptus-derived IFNT was hypothesized to induce IFN-stimulated gene (ISG) expression in endometrium and extrauterine tissues during pregnancy. To test this hypothesis, blood was collected from ewes on Days 12-16 of the estrous cycle or pregnancy. Serum progesterone was >1.7 ng/ml in pregnant (P) and nonpregnant (NP) ewes until Day 13, then declined to <0.6 ng/ml by Day 15 in NP ewes. A validated IFNT radioimmunoassay detected IFNT in uterine flushings (UFs) on Days 13-16 and in UVS on Days 15-16 of pregnancy. IFNT detection in UF correlated with paracrine induction of ISGs in the endometrium and occurred prior to the inhibition of estrogen receptor 1 and oxytocin receptor expression in uterine epithelia on Day 14 of pregnancy. Induction of ISG mRNAs in corpus luteum (CL) and liver tissue occurred by Day 14 and in peripheral blood mononuclear cells by Day 15 in P ewes. Expression of mRNAs for IFN signal transducers and ISGs were greater in the CL of P than that of NP ewes on Day 14. It is concluded that: 1) paracrine actions of IFNT coincide with detection of IFNT in UF; 2) endocrine action of IFNT ensues through induction of ISGs in peripheral tissues; and 3) IFNT can be detected in UVS, but not until Days 15-16 of pregnancy, which may be limited by the sensitivity of the IFNT radioimmunoassay.

Placental development during early pregnancy in sheep: estrogen and progesterone receptor messenger RNA expression in pregnancies derived from in vivo-produced and in vitro-produced embryos

Sex steroids are important regulators of angiogenesis and growth in reproductive tissues, including the placenta. In experiment (exp.) 1, to examine the expression of a suite of sex steroid receptors throughout early pregnancy, maternal (caruncular [CAR]) and fetal (fetal membranes [FM]) placental tissues were collected on days 14 to 30 after mating and on day 10 after estrus (nonpregnant controls). In exp. 2, to examine the hypothesis that assisted reproductive technology would affect the expression of the same suite of sex steroid receptors, pregnancies were achieved through natural mating (NAT) or transfer of embryos from natural mating (NAT-ET), in vitro fertilization (IVF), or in vitro activation (IVA), and CAR and FM were collected on day 22. In exp. 1, for CAR messenger RNA (mRNA) expression of estrogen receptors (ESR) 1 and 2, nuclear (n) progesterone receptors (PGR) and membrane (m) PGRα, β, and γ were affected (P < 0.02) by pregnancy stage, as were ESR1, nPGR, and mPGRα, β, and γ for FM (P < 0.03). In exp. 2, for CAR, mRNA expression of ESR1 and nPGR was decreased (P < 0.001) in NAT-ET, IVF, and IVA groups compared with NAT. For FM, mRNA expression of ESR1 tended to be greater (P = 0.10) in the IVA group compared with NAT and NAT-ET, and GPER1 was greater (P < 0.05) in NAT-ET and IVF compared with NAT. These data establish the normal pattern of sex steroid receptor mRNA expression in maternal and fetal placenta during early pregnancy in sheep, and in addition, suggest that altered expression of placental sex steroid receptors may be an early event leading to poor placental vascularization and growth after assisted reproductive technology.

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.

Embryo mortality in Isg15-/- mice is exacerbated by environmental stress

The interferon-stimulated gene 15 (Isg15) encodes a ubiquitin-like protein that is induced in the endometrium by pregnancy in mice, humans, and ruminants. Because ISG15 is a component of the innate immune system, we hypothesized that development of the embryo, fetus, and postnatal pup may be impaired in mice lacking Isg15 (Isg15(-/-)) and that this development would be further impaired in response to environmental insults such as hypoxia. The number of implantation sites, resorption sites, dead embryos, and the changes in overall gross morphology of the uterus were evaluated in Isg15(-/-) mice on Days 7.5 and 12.5 postcoitum (dpc). Postnatal development also was monitored from birth to 12 wk of age. On 7.5 dpc, the number of implantation sites and serum progesterone concentrations were similar. However, embryo mortality increased (P < 0.05) in Isg15(-/-) dams by 12.5 dpc, resulting in smaller litter sizes (4.26 ± 0.21 embryos; n = 83 litters) compared to Isg15(+/+) females (7.78 ± 0.29 pups; n = 47 litters). Embryo mortality in Isg15(-/-) mice was further exacerbated to 70% when dams were stressed through housing under hypoxic conditions (PB = 445 mmHg; 6.5-12.5 dpc). Transmission electron microscopy revealed lesions in antimesometrial decidua as well as trophoblast cells adjacent to decidual cells on 7.5 dpc. ISG15 was localized to mesometrial decidua on 7.5 dpc. By 12.5 dpc, ISG15 was intensely localized to the labyrinth of the placenta. By 7.5 dpc, uterine natural killer cell migration into the mesometrial pole was diminished by 65% and was less prevalent in Isg15(-/-) compared to Isg15(+/+) deciduum. Postnatal growth rate of offspring that survived to birth from Isg15(-/-) and Isg15(+/+) dams was not different. Embryo mortality occurs in pregnant Isg15(-/-) mice, is exacerbated by environmental insults like maternal hypoxia, and might result from impaired early decidualization, vascular development, and formation of the labyrinth.

Activation of the CXCL12/CXCR4 signaling axis may drive vascularization of the ovine placenta

Early pregnancy, when most embryonic losses occur, is a critical period in which vital placental vascularization is established. Vascular endothelial growth factor (VEGF) is a potent inducer of angiogenesis, and factors that regulate VEGF function, expression, or both may ultimately affect vascularization. Activation of the C-X-C chemokine receptor type 4 (CXCR4) by its cognate ligand, C-X-C chemokine ligand 12 (CXCL12), increases VEGF synthesis and secretion, which in turn stimulates CXCL12 and CXCR4 production and this synergistic regulation may influence placental vascularization. We hypothesized that expression of CXCL12, CXCR4, select angiogenic factors, and their receptors would increase in placental tissues during early pregnancy and that treatment of ovine trophectoderm cells with CXCL12 would increase production of angiogenic factors. To test this hypothesis, maternal caruncle (CAR) and fetal extraembryonic membrane (FM) tissues were collected on days 18, 20, 22, 25, 26, and 30 of pregnancy and on day 10 of the estrous cycle (control, NP) to determine relative mRNA or protein expression of CXCL12 and CXCR4 and selected angiogenic factors. In CAR, expression of mRNA for CXCR4 increased on day 18, 20, 22, and 25 and CXCL12 increased on day 18 and 20 compared with NP ewes. CXCL12 protein followed a similar pattern in CAR tissue, with greater levels on day 20 than in NP tissue. Greater levels of fibroblast growth factor 2 (FGF2) mRNA was observed in CAR on day 20 of gestation than on day 30. In FM, CXCL12, CXCR4, angiopoietin 1, VEGF, and VEGF receptor 1 were enhanced with advancing pregnancy, whereas FGF2 and kinase insert domain receptor (or VEGF receptor 2) peaked on day 25. An increase in protein levels occurred on day 25 compared with day 20 in FM for CXCL12 and CXCR4, as well as a similar tendency for FGF2 protein. Both CXCL12 and CXCR4 are specifically localized to trophoblast cells and to the uterine luminal and glandular epithelium. Treatment of ovine trophectoderm cells with CXCL12 increased mRNA expression for VEGF and FGF2. The relationship between VEGF, FGF2, and the CXCL12/CXCR4 signaling underscores the potential role for this chemokine axis in driving placentation.

The chemokine receptor CXCR4 and its ligand CXCL12 are activated during implantation and placentation in sheep

BACKGROUND

The progression of implantation and placentation in ruminants is complex and is regulated by interplay between sex steroids and local signaling molecules, many of which have immune function. Chemokines and their receptors are pivotal factors in implantation and vascularization of the placenta. Based on known critical roles for chemokine receptor 4 (CXCR4) during early pregnancy in other species, we hypothesized that CXCR4 and its ligand CXCL12 would increase in the endometrium and conceptus in response to implantation in ewes. The objectives of the current study were to determine if CXCL12 and CXCR4 were upregulated in: endometrium from pregnant compared to non-pregnant ewes and in, conceptuses, cotyledons, caruncles and intercaruncular tissue.

METHODS

Tissues were collected from sheep on Days 12, 13, 14, and 15 of either the estrous cycle or pregnancy and from pregnant ewes on Days 35 and 50. Blood samples from jugular and uterine vein were also collected on all days. Conceptuses were collected from mature ewes on Days 13, 15, 16, 17, 21 and 30 of gestation. Real time PCR was used to determine relative mRNA concentrations for CXCL12 and CXCR4 and Western blot analysis was employed to confirm protein concentration.

RESULTS

Differences described are P < 0.05. In the endometrium, CXCR4 mRNA and protein was greater on Day 15 of pregnancy compared to the estrous cycle. CXCL12 and CXCR4 mRNA in conceptuses was greater on Days 21 and 30 compared to earlier days. CXCL12 mRNA was greater in cotyledons on Day 35 compared to Day 50. On Day 35 of gestation, CXCR4 was greater compared to Day 50 in caruncle and intercaruncular tissue. White blood cells obtained from jugular and uterine vein collection had the greatest mRNA concentration of CXCL12 on Day 35 of pregnancy.

CONCLUSIONS

A comprehensive analysis of CXCL12 and CXCR4 expression in fetal and maternal tissues during early pregnancy is reported with noteworthy differences occurring during implantation and placentation in sheep. We interpreted these data to mean that the CXCL12/CXCR4 pathway is activated during implantation and placentation in sheep and is likely playing a role in the communication between trophoblast cells and the maternal endometrium.

Deletion of the Isg15 gene results in up-regulation of decidual cell survival genes and down-regulation of adhesion genes: implication for regulation by IL-1beta

The ubiquitin homolog interferon stimulated gene 15 (ISG15) is up-regulated in the endometrium in response to pregnancy in primates, ruminants, pigs, and mice. ISG15 covalently attaches to intracellular proteins (isgylation) and regulates numerous intracellular responses. We hypothesized that ISG15 depletion (Isg15(-/-)) alters decidual tissue gene expression and that IL-1beta induces ISG15 expression and isgylation in cultured murine decidual explants and human uterine fibroblasts (HuFs). After studying the reproductive phenotype, contrary to earlier reports, up to 50% of the fetuses die between 7.5 and 12.5 d post coitum (dpc) in Isg15(-/-) mothers when mated to Isg15(-/-) fathers. Using microarray analysis, over 500 genes are differentially regulated in 7.5 dpc deciduas from Isg15(-/-) compared with Isg15(+/+) mice. The gene for interferon-inducible protein 202b, which functions in cell-survival mechanisms, was up-regulated (mRNA and protein) in deciduas from Isg15(-/-) mice. Culture of Isg15(+/+) mouse decidual explants (7.5 dpc) with IL-1beta decreased Isg15 mRNA but increased free and conjugated ISG15. In predecidual HuF cells, IL-1beta treatment increased ISG15 mRNA and isgylation. Additionally, IL-1beta up-regulated expression of enzymes (HERC5, UBCH8) that coordinate the covalent conjugation of ISG15 to target proteins, as well as the gene that encodes the deisglyation enzyme UBP43 in HuF cells. In conclusion, deletion of Isg15 gene results in 50% fetal loss after 7.5 dpc, which can be explained through differential decidual gene expression that is functionally tied to cell survival and adhesion pathways. This fetal death also might relate to impaired IL-1beta signaling, because ISG15 and isgylation are induced by IL-1beta in human and murine endometrial stromal cells.

Membrane-initiated actions of estradiol (E2) in the regulation of LH secretion in ovariectomized (OVX) ewes

BACKGROUND

We demonstrated that E2 conjugated to BSA (E2BSA) induces a rapid membrane-initiated inhibition of LH secretion followed hours later by a slight increase in LH secretion. Whether these actions of E2BSA are restricted to the pituitary gland and whether the membrane-initiated pathway of E2BSA contributes to the up-regulation of the number of GnRH receptors during the positive feedback effect of E2 were evaluated here. We have shown that the suppression of LH secretion induced by E2 and E2BSA is the result of a decreased responsiveness of the pituitary gland to GnRH. In this study we further tested the ability of E2BSA to decrease the responsiveness of the pituitary gland to GnRH under the paradigm of the preovulatory surge of LH induced by E2.

METHODS

For the first experiment GnRH and LH secretions were determined in samples of pituitary portal and jugular blood, respectively, in ewes treated with 12 mg E2BSA. In the second experiment, the number of GnRH receptors was quantified in ewes 12 h after administration of 25 micrograms E2 (the expected time for the increase in the number of GnRH receptors and the positive feedback effect of E2 in LH secretion) or 12 mg E2BSA. In the third experiment, the preovulatory-like surge of LH was characterized in ewes injected with 25 micrograms E2 alone or followed 8 h later (before the beginning of the LH surge) with 60 mg E2BSA.

RESULTS

a) the decrease in LH secretion induced by E2BSA was not accompanied by changes in the pulsatile pattern of GnRH, b) E2BSA increased the number of GnRH receptors, and c) the presence of E2BSA in E2-treated ewes delayed the onset, reduced the length, and decreased the amount of LH released during the preovulatory surge of LH.

CONCLUSIONS

a) the rapid suppression of LH secretion induced by E2BSA is mediated only via a direct action on the pituitary gland, b) E2 acting via a membrane-initiated pathway contributes to increase the number of GnRH receptors and, c) administration of E2BSA near the beginning of the pre-ovulatory surge of LH delays and reduces the magnitude of the surge.

Binding characteristics of the ovine membrane progesterone receptor alpha and expression of the receptor during the estrous cycle

BACKGROUND

Classically, progesterone has been thought to act only through the well-known genomic pathway involving hormone binding to nuclear receptors and subsequent modulation of gene expression. However, there is increasing evidence for rapid, non-genomic effects of progesterone in a variety of mammalian tissues and it is possible that a membrane PR (mPR) is causing these events. We recently isolated and characterized an ovine mPR referred to as mPR-alpha, distinct from the nuclear PR. Based on predicted structural analysis, the ovine mPR-alpha possesses seven transmembrane domains typical of G protein-coupled receptors. Despite the homology to other reported mPRs, information pertaining to the steroid binding characteristics of the ovine mPR-alpha was lacking. Additionally, the ovine mPR-alpha transcript has been identified in the hypothalamus, pituitary, uterus, ovary and corpus luteum, yet changes in expression of the ovine mPR-alpha in these tissues were not known. Consequently, the purpose of this work was to determine the steroid binding characteristics of the ovine mPR-alpha and to investigate possible changes in expression of the ovine mPR-alpha in reproductive tissues throughout the estrous cycle.

METHODS

Binding studies were performed using crude membrane fractions from CHO cells expressing the mPR-alpha. Using quantitative Real-time PCR we determined the expression pattern of mRNA for the ovine mPR-alpha during the ovine estrous cycle in tissues known to express the mPR-alpha. Jugular blood samples were also collected and analyzed for serum concentrations of P4 to ensure ewes were at the appropriate stage of their cycle.

RESULTS

Only progesterone, 20alpha-hydroxyprogesterone and 17alpha-hydroxyprogesterone were able to displace binding of 3H-P4 (P < 0.001) to membrane fractions from CHO cells expressing ovine mPR-alpha. The average B-max and Kd values for three separate experiments were 624 +/- 119 fmol/micro gram protein and 122 +/- 50 nM, respectively. Significant changes in expression of mRNA for the mPR-alpha during the estrous cycle were noted in the corpus luteum and uterus.

CONCLUSION

The mPR-alpha specifically binds progestins and its expression was correlated to progesterone secretion during the ovine estrous cycle. Results from the present studies suggest that mPR-alpha may have an important physiological role during the ovine estrous cycle.

Expression of interferon (IFN)-stimulated genes in extrauterine tissues during early pregnancy in sheep is the consequence of endocrine IFN-tau release from the uterine vein

The ruminant conceptus synthesizes and secretes interferon (IFN)-tau, which presumably acts via an intrauterine paracrine mechanism to signal maternal recognition of pregnancy. The aims of this study were to determine whether IFN-stimulated genes (ISG) such as ISG15 and OAS-1 are differentially expressed in blood cells circulating in the uterus of ewes; whether extrauterine components of the reproductive tract such as the corpus luteum (CL) also express mRNA for these ISG, and whether antiviral activity is greater in uterine vein than in uterine artery during early pregnancy. The concentrations of mRNA for both ISG were significantly greater (P < 0.0001) in endometrium and jugular blood of 15-d pregnant ewes than in nonpregnant ewes. ISG15 and OAS-1 mRNA concentrations were also greater (P < 0.05) in CL from 15-d pregnant ewes than in nonpregnant ewes. Immunohistochemistry revealed intense staining for ISG15 in large luteal cells on d 15 of pregnancy. Blood cells from uterine artery and vein of 15-d pregnant ewes had similar ISG15 and OAS-1 mRNA concentrations, suggesting that these cells were not conditioned by IFN-tau within the uterus. By using an antiviral assay, uterine venous blood was found to contain 500- to 1000-fold higher concentrations of bioactive IFN-tau than in uterine arterial blood on d 15 of pregnancy. It is concluded that uterine vein releases IFN-tau, which induces ISG in extrauterine tissues such as the CL during the time of maternal recognition of pregnancy.

Cloning and characterization of an ovine intracellular seven transmembrane receptor for progesterone that mediates calcium mobilization

Classically, progesterone has been thought to act only through the well-known genomic pathway involving hormone binding to nuclear receptors (nPR) and subsequent modulation of gene expression. However, there is increasing evidence for rapid, nongenomic effects of progesterone in a variety of tissues in mammals, and it seems likely that a membrane PR (mPR) is causing these events. The objective of this study was to isolate and characterize an ovine mPR distinct from the nPR. A cDNA clone was isolated from ovine genomic DNA by PCR. The ovine mPR is a 350-amino acid protein that, based on computer hydrophobicity analysis, possesses seven transmembrane domains and is distinct from the nPR. Message for the ovine mPR was detected in hypothalamus, pituitary, uterus, ovary, and corpus luteum by RT-PCR. In CHO cells that overexpressed a mPR-green fluorescent protein fusion protein, the ovine mPR was localized to the endoplasmic reticulum and not the plasma membrane. Specific binding of 3H-progesterone to membrane fractions was demonstrated in CHO cells that expressed the ovine mPR but not in nontransfected cells. Furthermore, progesterone and 17 alpha-hydroxy-progesterone stimulated intracellular Ca2+ mobilization in CHO cells that expressed ovine mPR in Ca2+-free medium (P < 0.05) but not in CHO cells transfected with empty vector. This rise in intracellular Ca2+ is believed to be from the endoplasmic reticulum as intracellular Ca2+ mobilization is absent when mPR transfected cells are first treated with thapsigargin to deplete Ca2+ stores from the endoplasmic reticulum. Isolation, identification, tissue distribution, cellular localization, steroid binding, and a functional response for a unique intracellular mPR in the sheep are presented.

A population based study of herpes simplex virus 2 seroprevalence in rural Costa Rica

OBJECTIVES

To determine seroprevalence and determinants of herpes simplex virus 2 (HSV-2) seropositivity, in a random sample of a population based cohort of 10 049 women of Guanacaste, Costa Rica, using a highly sensitive and specific serological assay.

METHODS

Seroprevalence was determined by a type specific HSV-2 ELISA assay in an age stratified random sample of 1100 women. Univariate and multivariate logistic regression was used to calculate odds ratios and 95% confidence intervals for risk factors of seropositivity.

RESULTS

Overall age adjusted HSV-2 seroprevalence was 38.5% (95% CI, 37.5 to 39.5), and it was strongly associated with increasing age (p(Trend<0.0001)), both among monogamous women and women with multiple sexual partners. A greater number of lifetime sexual partners increased the risk of seropositivity, with a 28.2% (95% CI, 24.4 to 32.2) seroprevalence among monogamous women and 75% (95% CI, 65.6 to 83.0) seroprevalence for those with four or more partners (OR = 7.6 95% CI, 4.7 to 12.4 p(Trend<0.0001)). Barrier contraceptive use was negatively associated with HSV-2 seropositivity (OR 0.54, 95% CI, 0.31 to 0.94). Women with antibodies against HPV 16, 18, or 31 were 1.6 times more likely to be HSV-2 seropositive (OR 1.6, 95% CI, 1.2 to 2.1).

CONCLUSIONS

HSV-2 infection is highly endemic in Guanacaste, even among lifetime monogamous women, suggesting a role of male behaviour in the transmission of the infection. Until vaccination against HSV-2 is available, education to prevent high risk sexual behaviour and the use of condoms appear as preventive measures against HSV-2.

Sorting out the new HSV type specific antibody tests

This review will delineate performance characteristics and limitations, as far as they are known, of the new glycoprotein G based, type specific HSV serologies. Several of these tests have been FDA approved in the United States for use in adults. With the departure of Gull/Meridian from the HSV serology market, it is important for clinicians to understand the sources and claims of the remaining type specific tests. Moreover, inaccurate tests using crude antigen preparations remain on the market. These tests are identified based on product insert information provided by company representatives.

Prospective study of the natural history of infectious mononucleosis caused by Epstein-Barr virus

BACKGROUND

Knowledge regarding the clinical characteristics and natural history of acute infectious mononucleosis is based largely on older, often retrospective, studies without systematic follow-up. Differences in diagnosis, methodology, or treatment between historical and current practice might affect an understanding of this illness.

METHODS

Using a prospective case series design, we enrolled 150 persons with an acute illness serologically confirmed as Epstein-Barr virus infection. The goal of the study was to assess symptoms, physical examination findings, laboratory tests, and functional status measures during the acute presentation and 1, 2, and 6 months later.

RESULTS

Acutely, infectious mononucleosis was characterized by the symptoms of sore throat and fatigue and substantial functional impairment. Objective physical and laboratory examination findings included pharyngitis and cervical lymphadenopathy, a moderate absolute and atypical lymphocytosis, and mildly elevated transaminase levels. The traditional signs of fever and splenomegaly were relatively uncommon. By 1 month, most symptoms and signs and all laboratory tests had returned to normal. Fatigue, cervical lymphadenopathy, pharyngitis, and functional health status improved more slowly.

CONCLUSIONS

In contemporary practice most of the classical illness features of infectious mononucleosis are observed. Symptoms, signs, and poor functioning might be protracted in some patients.

Human papillomaviruses and cervical cancer in Bangkok. III. The role of husbands and commercial sex workers

Between September 1991 and September 1993, husbands of women with and without cervical neoplasia and commercial sex workers in one brothel and one massage parlor in Bangkok, Thailand, were interviewed; serologic tests for sexually transmitted infections were performed; and cervical and penile scrapings were tested for human papillomavirus (HPV) DNA. The risks of cervical carcinoma in monogamous women and of oncogenic HPV in their husbands were associated with the men's having unprotected intercourse with prostitutes. The prevalence of oncogenic HPV was higher in commercial sex workers than in women attending gynecologic and family planning clinics. Oncogenic HPV prevalence declined with age in human immunodeficiency virus (HIV)-negative, but not in healthy HIV-positive, commercial sex workers and was weakly associated with hepatitis B antigenemia, suggesting that persistence of HPV infection is due to subtle changes in immunity. Associations of HPV with recent pregnancy and oral contraceptive use suggest that hormonal factors may increase the risk of cervical neoplasia by enhancing persistence of HPV infection. The prevalence of high-grade squamous intraepithelial lesions was strongly related to oncogenic HPV types and weakly to HIV infection only in their presence. Commercial sex workers in Bangkok are reservoirs of oncogenic HPV, and cervical cancer in monogamous Thai women develops in part as a result of transmission of these viruses to them by their husbands from prostitutes.

Human papillomaviruses and cervical cancer in Bangkok. II. Risk factors for in situ and invasive squamous cell cervical carcinomas

To identify risk factors for progression of intraepithelial cervical lesions, 190 women with invasive cervical cancer were compared with 75 women with in situ disease diagnosed in Bangkok, Thailand, between September 1991 and September 1993. Polymerase chain reaction-based assays for type-specific human papillomavirus (HPV) DNA in cervical scrapings revealed oncogenic types in 79% of invasive and 57% of intraepithelial tumors. Types 16 and 18, but not types 31/33/35/39, were more common in invasive than intraepithelial tumors, and untyped HPV DNA was found more commonly in the in situ lesions, suggesting that in situ disease is four times more likely to become invasive if due to type 16 or 18 than to other causes, and that tumors with only untyped HPV are not at increased risk of progression. After controlling for HPV type, the risk of developing invasive diseases, compared with the risk of developing intraepithelial lesions, was not related to any of a large number of sexual and hormonal factors considered or to smoking, suggesting that any cofactors these variables represent act before the development of in situ carcinoma. Two indices of socioeconomic status were associated with a reduced risk of only invasive disease, suggesting the existence of unknown protective factors that operate after intraepithelial lesions develop.

Human papillomaviruses and cervical cancer in Bangkok. I. Risk factors for invasive cervical carcinomas with human papillomavirus types 16 and 18 DNA

Personal interviews, tests for antibodies to herpes simplex virus type 2, Treponema pallidum, and hepatitis B, tests for hepatitis B surface antigen (HBsAg), and polymerase chain reaction-based assays for human papillomavirus (HPV) DNA in cervical scrapings were obtained from 190 women with squamous cell and 42 women with adenomatous cervical carcinoma and from 291 hospitalized controls diagnosed in Bangkok, Thailand, between September 1991 and September 1993. Risk was strongly associated with oncogenic HPV types, with types 16 and 18 predominating in squamous and adenomatous lesions, respectively. The 126 cases with HPV-16 and the 42 cases with HPV-18 were compared with 250 controls with no evidence of any HPV. The risk of both viral tumor types increased with decreasing age at first intercourse in this predominantly monogamous population, which may be explained by more visits to prostitutes by the husbands of cases with early than late age at first intercourse. HPV-16 tumors were weakly associated with HBsAg carrier state and smoking. The risk of tumors of both viral types increased with parity and use of oral contraceptives but not with injectable progestogens. Factors that may predispose to persistent, oncogenic HPV-16 or -18 infection may include estrogens or progestins in the presence of estrogens, immunosuppression, and smoking, but other factors related to low socioeconomic status are also involved.

Prevalence and risk factors for herpes simplex virus type 2 infection among middle-age women in Brazil and the Philippines

BACKGROUND

Data comparing type-specific herpes simplex virus type 2 (HSV-2) seroprevalence and risk factors between comparable populations are largely unavailable, particularly from less-developed countries.

GOAL

To examine the seroprevalence of HSV-2 infection and the risk factors for this infection among women in São Paulo, Brazil, and Manila, the Philippines.

STUDY DESIGN

Altogether, 552 middle-aged women participating as control subjects in two cervical cancer studies were screened for type-specific HSV-2 antibodies.

RESULTS

Herpes simplex virus type 2 seroprevalence was higher in Brazil (42%) than in the Philippines (9.2%). The mean ages of Brazilian (n = 181) and Filipino (n = 371) women were 52.4 and 46.6 years, respectively. Brazilian participants had more lifetime sexual partners, less education, and more often a husband with other sexual partners than Filipino women. Herpes simplex virus type 2 was independently associated with younger age at first intercourse in both countries. More than one lifetime sexual partner, a husband with other sexual partners, urban/semi-urban residence, and no history of condom use were HSV-2 risk factors in Brazil, but not in the Philippines, where long-term hormonal contraceptive use was associated with increased risk.

CONCLUSIONS

The higher HSV-2 seroprevalence in Brazil than in the Philippines may be explained largely by differences in the sexual behavior of women and their husbands. Herpes simplex virus type 2 seroprevalence data may be used as a marker of past sexual behavior for the direct comparison of different population groups.

Parotid salivary basic proline-rich proteins inhibit HIV-I infectivity

OBJECTIVE

The objective of this study was to investigate the molecular nature, spectrum of activity and mechanism(s) of action of those human parotid basic proline-rich proteins that exhibit anti-HIV-I activity.

DESIGN

Fractions containing the basic proline-rich proteins were obtained from human parotid saliva of presumed HIV-I non-infected human subjects and characterized with respect to their purity, apparent molecular size and their ability to inhibit the infectivity of T-tropic and M-tropic strains of HIV-I.

SUBJECTS, MATERIALS AND METHODS

Stimulated parotid saliva samples were collected from human subjects who denied having any risk factors for HIV-I infection and whose parotid salivas inhibited HIV-I infectivity. Such samples were subjected to affinity, molecular sieve and ion exchange chromatography to isolate individual salivary components. Those fractions demonstrating anti-HIV-I activity were analyzed by SDS-PAGE in order to assess their purity and determine their apparent molecular weights. HIV-I inhibitory activity was determined using HIV-I strains LAI and BaL in a Hela cell-derived multinuclear activation of a galactosidase indicator (MAGI) assay. Amino acid analyses were performed on some fractions.

RESULTS

Recombinant gp120-CH-Sepharose chromatography of one subject's parotid saliva revealed specific binding of human parotid basic proline-rich proteins, most prominently one with an apparent molecular weight of 37 kDa. Molecular sieve and cation exchange chromatography yielded a fraction greatly enriched in this protein which amino acid analysis confirmed was proline-rich. A similar fraction from two other subjects also contained basic proline-rich proteins of similar molecular size. These fractions inhibited both T-tropic and M-tropic strains of HIV-I when assayed in the MAGI system. Since SLPI activity is not observable in the MAGI assay, this inhibition was not due to SLPI. The presence of thrombospondin-I (TSP-I) in the active fractions was precluded on the basis of SDS-PAGE examination.

CONCLUSIONS

Specific basic proline-rich proteins in human parotid saliva possess significant anti-HIV-I activity independent of that attributable to SLPI or TSP-I. Since the inhibition is detectable with the MAGI assay, its mechanism of action involves virus-host cell interaction prior to the introduction of the tat gene product into the host cell and may be through the binding of the basic proline-rich proteins to the HIV-I gp120 coat of the virus.

Use of a glycoprotein G-based type-specific assay to detect antibodies to herpes simplex virus type 2 among persons attending sexually transmitted disease clinics

BACKGROUND

Most genital herpes simplex virus type 2 (HSV-2) infections are unrecognized, thus, strategies to reduce the sexual transmission of HSV-2 are partly dependent on serologic screening.

GOAL

To define performance characteristics of the Gull/ Meridian glycoprotein G-based HSV-2 enzyme-linked immunosorbent assay among sexually transmitted disease clinic attendees and correlates of test acceptance.

STUDY DESIGN

The cross-sectional study was conducted during two periods. Serologic testing was offered at a US $15 charge during the first period and at no charge during the second period. Sera were tested by a type-specific glycoprotein G enzyme-linked immunosorbent assay and Western blot analysis, with the latter test used as the reference standard.

RESULTS

Acceptance of HSV-2 testing was associated with free testing (odds ratio, 7.5; 95% CI, 6.0-9.9), older age, and white race. Sensitivity of the HSV-2 assay was 80.5% and specificity was 98.5%. The HSV-2 positive and negative predictive values were 95.8% (95% CI, 91.6-98.0%) and 92.2% (95 % CI, 89.6 -94.2%), respectively. Antibodies to HSV-2 were detected in 25.9% of 606 persons with no history of genital herpes.

CONCLUSION

Acceptance of HSV-2 serologic testing was cost sensitive. In this high-prevalence population, the positive predictive value of the enzyme-linked immunosorbent assay was sufficient to warrant its use without a confirmatory test. This assay could be useful in the screening of sexually active adults to detect unrecognized HSV-2 infection.